Hydraulic dynamometer US 2452550 A

DESCRIÇÃO

Nov. 2, 1948. E. L. CLINE 2,452,550

HYDRAULIC DYNAMOMETER Filed may 20, 1942 5 Sheets-Sheet 1 E. L. CLINE HYDRAULIC

DYNAMOMETER Nov. 2, 1948.

5 Sheets-Sheet 2 Filed May 20, 1942 Nov. 2, 1948.

E. L. CLINE ummumc DYNAMOMETER 5 Sheets-Sheet 4 Filed May 20, 1942 Nov. 2, 1948. E.

CLINE 2,452,550

I HYDRAULIC DYNAHOMETER Filed May 20, 1942 5 Sheets-Sheet 5 by, "'im/ atented T

HYDRAULIC DYNAMOMETER Edwin H... Cline, Pasadena, Calif assignor to Clayton

Manufacturing Company, Alhambra, Calif.

Application May 20, 1942, Serial No. 443,833

This invention relates to dynamometers for general use in testing motor vehicle and engine

hydraulic dynamometer is the provision of a closed, uninterrupted or continuous circulating

system for the liquid employed in the hydraulic brake unit. This liquid in most instances is water

because of its cheapness and ready availability, .but it will be understood that any other suitable

liquid may be employed. Prior known hydraulic dynamometers have employed water and other

liquid mediums in a brake unit, but the arrangement was usually such that the liquid flowed

continuously through the brake unit and discharged into a container open to the atmosphere, or

to waste, the rate of flow being regulated manually by ordinary hand valves. The inherent defect

of such arrangement is that it is impossible to maintain a constant load on the engine and to

substantially duplicate the same load in repeating or making further tests on the engine. Another

factor that has rendered prior hydraulic dynamometers unsatisfactory is that the liquid used

therein was usually water under pressure from a city service line, the water obviously being

subject to fluctuations in flow depending upon the demand, as will be readily understood, so that

it was furtherimpossible to maintain a. constant dynamometer load.

In marked contrast, the present invention comprises a hydraulic brake unit having a housing or

casing, a shaft rotatably mounted in the casing and a rotor wheel in the casing secured to said

shaft. The casing of the brake unit is interconnected by elements of a. piping system in an endless

circuit with a heat exchanger containing relatively small tubes through which the brake liquid is

passed. Cooling water flows through the heat exchanger in contact with the exterior of the small

tubes and effects cooling of the brake liquid before it is returned to the brake housing. The rotor

of the brake unit acts, in efiect, like a centrifugal pump, causing rapid circulation of the brake liquid

through the small 41 Claims. (Cl. 188-90) tubes of the heat, exchanger. The volume of brake

liquid in the housing can be varied, but in normal use it contains sufiicient brake liquid to maintain

a desired load on the engine being tested and, of course, the heat exchanger is completely filled

with the brake liquid so that as the rotor is rotated it forces a portion of the brake liquid out of the

housing and into the heat ex changer, and an equal volume is forced out of the 'heat exchanger

and returned to the housing. Thus, a closed circulating system is provided for the brake liquid,

and the volume of brake liquid in the housing is maintained constant for any given load and,

therefore, the load imposed by the brake liquid also remains constant.

The piping system aforementioned also includes a service line and a drain line connected with

the brake unit, and valves, preferably remotely controlled, are connectedin said piping so that the

dynamometer operator can open one valve to admit water into the brake housing to increase the

volume of liquid in the brake and thereby increase the load absorption capacity of the brake unit,

or operate another valve to drain water from the brake unit to reduce the load absorption capacity

of said brake unit. Once the desired loading of the brake unit has been attained, it is normally

impossible for water to either get into or out of the closed system without further operation of the

valves and, hence, the load absorption capacity of the brake unit will remain constant. It will be

readily apparent that by varying the volume of water in the housing of the brake unit, a vehicle

may be tested at any desired load corresponding to any road speed, for example, 10 to miles/hour

or more.

The brake unit itself embodies a novel vane construction and is not limited to dynamometer use.

On the contrary, the brake unit is useful, for example, as a vehicle brake and the housing and

rotor can be readily associated with any rotating element, such as a truck propeller shaft to retard

its rotation and slow down the vehicle, especially .on hills. The effectiveness of the brake can be

varied by controlling the'volume of liquid in the housing by remote control means such as

disclosed herein and the liquid can be cooled by circulating the same through any suitable heat

exchanger. Hence, the brake unit is claimed broadly herein in combination with a heat exchanger

and closed circulating system.

A very important factor contributing to the success of the present chassis dynamometer is the

provision for high circulating velocity of the brake liquid through the tubes of the heat exchanger.

A high circulation velocity is desirable, not merely for the purpose of adequately cooling the brake

liquid, but primarily to prevent the brake unit from being subjected to variations or pulsations in

load which would defeat the accuracy of the dynamometer. More explicitly, it was discovered

during the development of this invention that there is a tendency for the rotor of the brake unit

when rotating to force or beat air into the brake liquid, much the same as air is beaten into cream

to make whipped cream. If air is thus introduced into the brake liquid and the mixture of air and

liquid is circulated through a heat exchanger, there is a tendency'for the small air bubbles to

collect and form relatively large pockets or slugs of air. As these air pockets reach the low

pressure side of the brake housing the air actually enters the brake housing to, in effect, take the

place of the air and liquid mixture that is being continuously forced out of the brake housingby the

rotor into the tubes of the heat exchanger. Hence, the volume of liquid in the brake unit is

momentarily slightly reduced and the load absorption capacity of the brake unit is correspondingly

reduced. Immediately following the introduction of the air slug or pocket into the brake housing, a

mixture of air and liquid, or liquid alone, will then be. introduced into the housing so that the volume

of brake liquid in said housing is momentarily slightly increased, producing a correspondingly

slight increase in the load absorption capacity of the brake unit. The intermittent or successive

introductions of air and liquid into the brake housing produce objectionable fluctuations in load

which prevent a constant load from being applied to the engine undergoing test.

In arriving at the present construction, it was found that the use of a suitable number of small

tubes in the heat exchanger together with a high circulating velocity prevented air from collecting

in slugs or pockets in the brake liquid as it was circulated through said tubes. With air pockets

thus excluded from the brake liquid, the brake unit is rendered capable of maintaining any desired

constant load upon the engine being tested. In addition, the high circulating velocity of the brake

liquid effected by the action of the rotor and the consequent rapid cooling of said liquid in the heat

exchanger keeps the brake liquid cool enough to make it feasible to use a closed system for the

brake liquid.

The heat exchanger for the hydraulic brake unit is constructed so that it can be conveniently

mounted in the frame of the dynamometer. This heat exchanger is preferably cooled by water

under pressure drawn from a service pipe and circulated through the heat exchanger. However,

any conventional cooling means such as a fan, blower, etc, (not shown) may obviously be used

with the heat exchanger in lieu of water. The dynamometer frame, which carries the piping

associated with the hydraulic brake unit. has suitable couplings adapted to be connected to a

service line and drain line at the location where the dynamometer is set up. In the heat exchanger,

the cooling water is preferably circulated in a direction opposite to the flow of the liquid to be

cooled.

One of the more important objects of the invention is to provide a chassis dynamometer suitable

for testing all types of motor vehicles'under conditions simulating as nearly as possible those

encountered on the road.

A more specific object of the invention is to provide a dynamometer of the hydraulic type

particularly adapted for use in automobile servicing establishments, breaking-in engines, in

petroleum absorption capacity of the brake unit can be mainvide a closed" system in which the

brake liquid tained constant, and whichcapacity can be varied by the dynamometer operator,

preferably by an electrical remote control device which can be conveniently held in the hand and

actuated by the operator while seated behind the steering wheel, or while standing beside the

vehicle.

Still another object of the invention is to provide a hydraulic dynamometer in which the liquid

employed in the brake unit, or power absorption unit, is circulated through a heat exchanger,

cooled during its passage through said heat exchanger, and then returned to said unit, the unit

and heat exchanger being interconnected to prois circulated.

Another object of the invention is to provide a hydraulic brake unit constructed so that a high

speed rotor can be used for power or energy absorption, and whereby quick loading and

unloading, together with great lugging-down ability are provided.

Still another object of the invention is to provide a hydraulic dynamometer including a brake unit

and a heat exchanger arranged to provide a closed" circulating system for the brake liquid and

wherein the brake liquid has a high circulation velocity to prevent the formation of air pockets or

slugs in said brake liquid which would cause fluctuations in the load absorption capacity of the

brake unit.

Still another object of the invention is to provide a dynamometer that can be unloaded quickly at

a predetermined rate simulating acceleration conditions on the road.

A somewhat broad object of the invention is to provide a power or energy absorption device in

the form of a hydraulic brake adapted for general use. That is to say, a hydraulic brake device

adapted for use in a dynamometer to absorb the power delivered by an engine shaft; on a motor

vehicle (for example, a heavy truck) to serve as a brake to slow down the vehicle; etc.

Still another object of the invention is to provide dynamometer apparatus that can be operated by

one person who can also make any adjustments on the engine or replacements that may be

necessary.

Still another object of the invention is to provide a complete chassis dynamometer apparatus

which is compact, relatively simple in construction, low in cost, and which can be readily

transported from one locality to another, if desired.

Further features, advantages and objects of the invention will be apparent from the following

description taken in conjunction with the accompanying drawings in which:

Fig. l is a perspective view of a complete, portable chassis dynamometer apparatus including a

dynamometer unit, an instrument stand, ramps and chocks;

Fig. 2 is a plan view of the chassis dynamometer unit shown in Fig. 1;

Fig. 3 is an enlarged view partially in section taken on the line 3-3 of Fig. 2, and particularly

illustrating the dynamometer unit supported by its casters, with the hydraulic brake unit in

elevation aseacso providing a direct reading of the horsepower be--' ing developed by the engine

undergoing test;

Fig. 8 is an enlarged view through the hydraulic brake unit taken on the line 33 of Flg. 4:

1'18. 7 is a sectional view taken on the line 1-1 of Fig. 6 showing the vane arrangement in one of

the sections of the brake housing;

Fig. 8 is a side elevational view of the rotor or power absorption wheel of the brake unit shown in

P18. 6; 1

Fig. 9 diagrammatically illustrates the hydraulic brake unit, the load control means therefor and

the heat exchanger associated therewith through which the, brake liquid is circulated and cooled;

Figs. 10 and 11 are enlarged sectional views through the heat exchanger taken on the lines Ill-ill

and il--l l, respectively, of Fig. 9; and

Figs. 12 and 13 are enlarged sectional views through the heat exchanger taken on the lines l2-lt

and l3-l3, respectively, of Fig. 9.

Referring now to Figs. 1 to 4 of the drawings, the portable chassis dynamometer frame is

rectangular in plan and is generally identified by the numeral l. The frame 8 comprises

longitudinally extending side members 2 and 3 spaced apart and interconnected by transverse

end members d and E and an intermediate transverse member 6. All of the members 2 to 6 are

preferably made of structural steel generally O-shaped in cross-section. The transverse members

d and d are connected by a longitudinally extending section l, and the section l is connected to

the side member 3 by a short transverse member ii. The frame i, as a whole, is stiffened by six

gusset plates 9 positioned on the underside of the frame at each corner thereof and adjacent the

transverse member 6. The parts 2 to d, inclusive, are preferablywelded together and provide a

very rigid frame structure; However,--it will be understood that these parts may be riveted or

otherwise secured together, if desired.

A pair of dynamometer rolls ill and ii is mounted horizontally within the frame i between the

transverse members 5 and 8. The rolls i0 and H are of a length sufllcient to be engaged by both

rear wheels of a motor vehicle, whereby the natural frequency of vibration of the rolls is reduced

somewhat, thus avoiding resonance. The rolls are also balanced to avoid dynamic vibration during

rotation. The roll It is an idler and is supported at its opposite ends in bearing blocks it, one of

which is secured to the end members by bolts l3 and the other of which is secured to the

intermediate transverse member 6 by bolts id. The roll it serves as a driver or power take-oil for

transmitting the power from the rear wheels of a motor vehicle to the brake unit B .of the

dynamometer. The roll H is mounted in bearing .blocks l5 similar to the bearim blocks l2. One of

the bearing blocks i5 is secured to the end member 5 by bolts l6 and the other bearing block is

secured to the intermediate transverse member 6 by bolts i1.

'18. 3 illustrates indetail themannerinwhich the rolls are. supported in the bearing blocks. All of

the bearing blocks l2 and I! are similar in construction and hence a description of one will sumce

for all. Each of the rolls is supported at its opposite ends in ball bearings II, the inner element ll of

which is carried on a reduced extension 20 of the rolls lO-l land the outer element 2! of which is

received ina rubber grommet 22 carried by the bearing blocks 12, II and serving as an insulating

material. As is shown, the grommet 22. is generally U-shaped in cross-section and partially

surrounds the outer ball bearing element 2|. The use of the. rubbermounted ball bearings at the

opposite ends of the rolls is conducive to .very quiet operation of the rolls.

A pair of ramp members 23 is provided to enable the vehicle to bebacked onto the rolls l0 and II

for test purposes. Each of the ramps 23 includes an inclined portion 24 and a substantially

horizontal portion 25, the latter portion resting upon the upper edge of the side member 3 and

having an extremity in close proximity to theperiphery of the roll I l. The ramps 23 are maintained

in operative relation to the side member 3 by means ofremovable screws 26 which enable the

ramps 23 to be readily detached when desired.

Ordinarily no dliliculty is experienced in backing a vehicle onto the rolls l0 and ii. However, in order

to drive the vehicle oil? the rolls it is necessary to lock at least one roll against rotation. To

accomplish this, each of the rolls l0 and l i carries a ratchet wheel 21 at the end thereof near the

frame member 5 adapted to'be engaged by a manually operable pawl 28 pivotally mounted upon

a pin 29 and having an integral arm 36 adapted to be grasped by the operator to eifect

engagement or disengagement of the pawl.

In view of the possibility that the floor surface upon which the portable dynamometer is to be used

may not be substantially level, the frame I carries three pairs of adjustable feet, one pair being

secured to the-frame members 2 and 3 ad- Jacent each of the ends of the rolls iii and ii and a

third pair being secured adjacent the left extremity of the frame, as best shown in Fig. 2. Each

pair of feet is associated with a pair of brackets M, 32 and 33 secured to the side membars 2 and

301- the frame I by bolts 34. The feet associated with the pairs of brackets 32 and 33 are each

provided with a rubber pad 38 adapted tc engage the floor and serve to prevent vibration noises.

In contrast, the pair of brackets 39 carries metal feet 39 directly engaging the ground to serve as

stabilizing feet for the brake end of the dynamometer.

The end frame members land 5 of the frame l I a each carry a pair of brackets 43 to receive

retractable swivel casters M: The casters M are removed or retracted to enable the feet 38 and

33 to support the framed when the unit is in use. The frame I, brackets 40, casters M and feet 88

and 39 are described and illustrated in greater detail, and claimed, in a divisional application Serial

No. 775,767, filed September 24, 1947.

The brake or power absorption unit of the dynamometer is generally indicated by the letter B and

is probably best shown in Figs. 3, 4 and 6. This unit includes a drum-like casing or housing 50

consisting of two sections 5i and 52 having annular portions terminating in radially extending new

form a seal. A brakeshaft I extends through the housing sections it and 52. The section Ii carries

a bracket 51 in which is mounted a ball bearing 58 providing a support for one end of the shaft 55

and the section 52 carries a somewhat similarvbracket 5! in which is mounted a ball bearing 60

forming a support for the opposite end of said shaft. through an opening 5| (Fig. 6) in the side wall

SI of the section 5! and is surrounded by packing 53 held in place by a packing gland 84. The

shaft 55 also extends through an opening 65 in the side wall 66 of the casing 52 and is surrounded

by packing 1 held in place by a gland 65. Thus, the shaft 56 is packed in each of the housing

sections 5| and 52 so that no fluid can escape from the housing" along said shaft.

Each of the housing sections 5i and 52 is pro-v vided with integral vanes ll extending tangentially

from a central hub portion ll (Figs. 6 and 7) to the inner periphery of the annular wall portion of the

respective housing sections. It will be clear from Fig. '7 that nine tangential vanes iii are provided

in each housing section. The vanes 10 are of uniform axial height for about twothirds of their

length and hen increase in height as indicated by the inwardly inclined portions 12 (Fig. 6). In

addition to the tangential vanes, each of the housing sections II and 52 carries transverse inwardly

extending webs 13, one of which is disposed between each two adjacent tangential vanes III.

A dynamically balanced power absorption rotor or brake wheel 14 (Figs. 6 and 8) is disposed in

the housing 5J-between the sections 5i and 52 and is secured to the shaft 58 by a key 15 received

in a keyway I5 cut in said shaft. Set screws I'l extend through a hub portion 18 of the rotor II and

retain said rotor in a central position on the shaft 55.

The rotor M has a central circular web I9 extending radially from the hub I8 to a pointadjacent the

innermost edge of the webs I3. Upon each side of the central web 19 is disposed a series of

radially extending substantially equally spaced vanes 80 which project from the hub 18 to the

periphery of the rotor. The vanes 80 are of uniform axial height for about two-thirds of their length

and then taper, as indicated at 8!, toward the peripheral portion of the wheel, as is best shown in

Fig. 6, said vanes terminating in end portions 82 flush with the periphery of the central web 19.

The tapered portions 8| are disposed at about the same distance from the axis of the shaft 55 as

the inwardly inclined portions 12 of the tangential vanes I0. However, as will be observed from

Fig. 6, the inclined' vane portions I2 and 8i are not parallel but diverge outwardly relative to each

other to give more linear action of loading.

It will be noted from the foregoing description that the brake housing sections 5| and 52 con tain

an odd number of vanes, to-wit, nine on each side wall, whereas the brake or rotor M has an even

number of vanes, to-wit, eight on each side of the central web 19. For the purposes of the present

invention, the relationship could be reversed. That is to say, the rotor ll could have the odd number

of vanes and the casing or housing sections 5| and 52 an even number of vanes. Similarly, the

tangential vanes could be formed on the rotor instead of on the housing, as will be readily apparent

without further illustration or description. The object in having one of the cooperating parts

provided with tangential vanes The shaft 58 extends rotor vanes cooperate to form a "working

circuit for the brake liquid, as is well understood. The brake unit 5!! is mounted upon the frame I i

by hearing brackets and 86 (Figs. 3 and 8),

the bearing bracket 85 being secured to the short transverse frame member 8 by bolts 81 and the

bearing bracket 86 being secured to the transverse end member' I by bolts 88. The bearing

brackets 85 and 86 support the brake unit 50 with the axis of the shaft 56 disposed upon an angle

relative to the axis of the drive roll II. as best illustrated in Fig. 3. The disposition of the shaft 56

upon an angle makes it possible to provide a chassis dynamometer which does not require a pit,

or the raising of the dynamometer frame and rolls to a substantial height above the level of the

floor. I As is shown in Fig. 6, the outer end of the shaft 56 carries a ball bearing 89 which is

mounted in a rubber grommet or insulator 90 in the bearing bracket 85. The opposite end of the

shaft 56 is similarly mounted in a ball bearing 9! and rubber grommet 92 in the bearing bracket

85.

The brake shaft 56 (Fig. 3) carries one element 93 of a universal joint at its lowermost end and

this element is connected to a cooperating element 94 carried by one end of an intermediate shaft

95. The opposite end of said intermediate shaft also carries one element 85 of a universal joint

which is operatively connected to another universal joint element 91 secured to the extension 20

of the dynamometer drive roll H. Thus. it will be apparent that rotary motion imparted to the roll H

by the driven wheels of a vehicle will be transmitted to the brake rotor ll through the intermediate

shaft 95 and the brake shaft 55.

The housing section ii is provided with a threaded opening Hi0 (Figs. 6 and 7) adjacent the hub II

or low pressure zone of the brake .unit B in which is mounted an elbow Iili connected to a section

of hose I02, whereby water or other brake liquid can be returned to the housing after passing

through a heat exchanger, as will be explained more fully hereinafter. The housing section 52 has

a threaded opening I03 (Fig. 6) into which is threaded a pipe nipple I04 having one end of a hose

I05 connected thereto. The housing. sections have registering depressions providing a pocket I!!!

adjacent the opening M3 to facilitate displacement of the brake liquid by the rotor ll during

unloading and for circulation through the heat exchanger referred to above. The hose section I05

serves as an inlet hose for the heat exchanger and in addition is associated with water supply,

drain piping and valves for effecting loading and unloading of the brake unit B, as will also be

described more fully hereinafter. The housing section 52 has a petcock I08 (Fig. 3) mounted

therein at the pocket I03 to permit complete draining of the brake unit when not in use. The

housing section 5| has an air check valve Hi6 mounted in. the side wall 52 thereof to permit air to

enter the brake unit and prevent the formation of a vacuum therein whenever water is drained

from the brake unit B. In some constructions it is also desirable to include an air bleed opening It

in the housing 50 on the leeward side of one of the stator vanes iii to provide atmospheric pressure

in the brake unit so that no water into said housing.

substantial pressure will be The housing section I carries a torque arm I01 (Figs. 4 and 5). One

end I08 of the torque arm I01 is secured to said housing section by bolts I09 and the opposite

end of said torque arm is connected to the threaded end III of a rod II2 by a self-locking nut II3.

The rod H2 is part of a torque brid e device I I4 for, in effect, "weighing" the torque produced by

the engine undergoing test. The rod II2 carries an arm I28 (Fig. 9) having a rounded contact finger

I32 which normally engages a potentiometer coil I28. The coil I28 is arranged in a circuit, not

essential to the invention claimed herein, to give a direct meter reading of the horsepower

developed by the engine undergoing test, the readings being dependent upon the amount of

vertical movement of the rod H2, which changes the position of the finger I32 with respect to the

potentiometer coil I28 so as to vary the amount of current which will flow through said coil to a

horsepower meter 35I (Fig. 1) mountedupon a stand 8. A plug I38 (Fig. 4) electrically connects

the torque bridge II4 with a generator G to be briefly described later.

The torque bridge device I I4 carries a dependent boss I39 (Fig. 5) which has a stud I40 mounted

therein. The stud I40 is secured to a bracket I42 on one of the gusset plates 9 by a self-locking

nut I40.

The bracket 59 on the housing section 52 carries a laterally extending arm I45 (Figs. 4 and 5)

constituting one element of the generator G, the inner end of which is secured to said bracket by

bolts I48. The opposite end of the arm I45 ter- I41 carries a generator stator coil assembly I48

mounted upon a stem I49 which projects ithroug the portion I41 and is adjustably held in plac 245'

by nuts I50 disposed uponopposite sides of said portion I41. A cooperating generator rotor I is

required to introduce eign matter from gaining'entrance into the system. The pipe line I8I also

includes a solenoid valve I85 interposed between the strainer I84 and the four-way fitting I52. The

valve I58 serves as a "loading valve for admitting water into the brake unit housing 50 to increase

the load imposed by thebrake unit and is adapted to be operated by a remote control device I51

(Figs. 1 and 9) including a push button switch I58 marked "On" which maintains the circuit closed

so long as the button is held depressed by the operator. The actuation of the button switch I58

causes the solenoid valve I85 to open and thereby admit water through the hose I05 into the

brake unit B to increase the volume of liquid therein and correspondingly increase the

power'absorptlon capacity thereof.

As will be apparent from Fig. 9, when the button I58 is depressed, a circuit to the solenoid valve

I85 is completed as follows: through lead wire I 89, push button switch I88, line I10, through the

solenoid coil of the valve I85 and through the line IN to the other lead wire I12.

An outlet coupling overlying the frame member 2 is indicated at I13 (Fig. 4) and is adapted to be

connected to a drain or sewer line D. The outlet coupling I13 is connected to a drain pipe line I14

which includes a solenoid valve I18 communicating with an opening of the four-way fitting I82 and

serving as an unloading valve. As will be apparent, the solenoid valve I18 controls communication

between the hose I05 and the drain line I14. Thus, when the valve I18 is,..energized, it will permit

draining of fluid from the brake unit B through the multi-purpose hose I05 and the pipe line I14,

thereby reducing the volume of liquid in the housingof the brake unit secured to the brake shaft

55 by a key I55 so that which successively pass the ends of a permanent horseshoe magnet I58.

The rotor I55, in cooperation with the coil assembly I48, acts as a generator to generate voltage

in proportion to the-speed of the brake shaft 55. The generator coil assembly I48 is connected in.

a circuit (not shown) with the potentiometer coil I28 and to suitable meters 359 and 35I (Fig. 1)

for giving a direct reading of thespeed and horsepower, respectively, that would be developed b

the vehicle under test, if it were operating on the road. The manner in which the generator G is

connected in circuit with the potentiometer coil I28, speed meter 350, horsepower meter 35I, etc.,

is fully disclosed, and claimed, in a continuation-in-part application Serial No. 775,765, filed

September 24, 19437.

As has been stated hereinbefore, the hydraulic brake unit 3 is associated with a closed system

including a heat exchanger for cooling the brake liquid which absorbs the power in the brake unit.

Referring now to Figs. 4 and 9, the numeral I50 indicates a pipe coupling overlying the frame

member 2 (Fig. 4) and adapted to be connected to a water supply line L at the location where the

dynamometer is to be used. The coupling I5!) is associated with a pipe line I8I which includes a

four-way fitting I52, one opening of which has a pipe nipple I53 mounted therein and to which is

connected one end of the multi-purpose hose I05, previously referred to. The pipe line I5I includes

and correspondingly reducing the load absorption capacity of said unit. The solenoid valve I18,

like the solenoid valve I55, is adapted to be controlled from a remote point by the remote control

device I51. When the operator desires to unload the brake unit, that is to say, reduce the load

absorption capacity thereof, a push button switch I11 (Fig. 9) marked Oil is depressed, thereby

completing the circuit to the valve I15 through the lead I59, push button switch I11, line I18,

through the coil of the solenoid valve I15, through lines I19 and I" back to the lead wire I12.

It will be apparent from the foregoing that the control device I81 enables the operator to control

the valve I88 or the valve I18 to respectively raise or lower the level in the brake unit B from a

remote point, whereby to vary the volume of brake liquid in said brake unit to determine the load

absorption capacity thereof. The control I81 is adapted to be conveniently held in the hand of the

operator and can be operated, for example, when the operator is seated at the wheel of the car

and is depressing the accelerator pedal with his foot.

The hose connection I05, in addition to serving as a conduit means for loading and unloading the

hydraulic brake unit B, also serves as a part of the closed circulating system through which the

brake liquid from the housing 50 passes from the lowest point of the system to a heat exchanger

generally indicated by the numeral I80. The heat exchanger [I preferably comprises two lengths

of brass pipe I 8| and I82 adapted'to be disposed parallel to each other and to be received within

the hollow portion of the C-shaped side I (seven) of relatively small copper tubes I99.

11 channel member 2 of the frame I. As is shown in 2. the heat exchanger -I99-is secured to the

member 2 by suitable clamping means I99.

One end ofthe pipe III is sweated into'an angle header fitting I99 and the opposite end of said

pipe is sweated into a manifold or return flow fitting I94. Similarly, one end of the pipe I92 is

sweated into an angle header fitting I99 and its opposite end is sweated into the reverse fiow

fitting I94. Pipe I9I contains a series The tubes I99.are mounted at one end in leakproof relation

"in a plug I91 having an opening for each tube, and the plug itself is mounted in the fitting I 99 in

sealed relation to the inner walls of said fitting. The opposite end of the tubes I99 is received in

openings I99 (Fig. 13) formed in the reverse or return flow fitting I94, the ends of the tubes being

soldered or otherwise mounted in said openings so as to prevent leakage along said tubes

through said openings. In a similar manner, a series (seven) of copper tubes I99 is received in

the pipe I92 with one end of said tubes I99 sealingly received in openings in a plug "I (Fig. mounted

in the fitting I99 and with the opposite end of said tubes received in openings I92 in the fitting I94.

It will be understood that the plugs I91 and I9I are arranged to allow fiow only through the tubes

associated therewith and that the fiow from the set of tubes I99 to the set of tubes I99 is permitted

by a passage I92 in. the fitting I94. It will be further understood that the flow of cooling water along

the exterior of the tubes I99 and I99 through the pipes IN and I92 is in nowise restricted and that

the cooling water from the pipe I9I can pass into the pipe I92 through a second passageway I94

in the fitting I94.

It will be noted from Figs. 4 and 9 that the four-way fitting I92 is connected by a pipe line I99 with

an end of the angle fitting I91 and that the fitting I99 carries a pipe nipple I99 to which is connected

the return hose section I92, previously referred to. Thus, the fluidin the brake housing 99 is

adapted to be introduced through the hose I99 and pipe line I98 into the copper tubes I99 from

whence it flows through the passage I99 into the copper-tubes I99, to be eventually returned

through the hose I92 to the brake housing 59. It will be further noted that cooling water from the

inlet pipe line IBI is adapted to be diverted through a pipe line 299 and introduced into the fitting

I95. This water fiows through the pipe I 92 in a direction opposite to that of the brake liquid, enters

the passage I94 in the fitting I84, returns through the pipe I9I (cooling the liquid contained in the

tubes I99 and I99) and is then discharged through a pipe line 29I and suitable fittings into the

drain pipe I14. A manually operated valve 292 is inter! posed in the line 29I to control the rate of

discharge of the cooling water from the heat exchanger I99.

As is best shown in Fig. 4, the pipe line I9I terminates in a male coupling 294 and a pipe line 29!

forms a continuation of the pipe line 29l and terminates in a female coupling 299. The couplings

294 and 295 are located at a height slightly above the top of the side member 2 and are adapted

to be connected to hose sections 299 and 213 provided with coupling elements 29I and 214,

respectively, for connection with an auxiliary radiator liquid cooling means, which it is unnecessary

to describe herein in detail, mounted in the instrument stand S.

However. the auxiliary engine cooling means and the method involved are fully disclosed, and

claimed, in a divisional application Serial No. 775,766, filed September 24. 1941.

The power absorption unit B and the various piping and related mechanism shown in Fig. iare

enclosed by a hood 299, as is best shown in Figs. 1 to 3. The transverse bottom edges of the

hood are turned inwardly as indicated at 291 (Fig. 3) and are adapted to rest upon the end frame

member 4 and the intermediate transverse frame member 9. The hood 299 can be secured in

place upon the frame I in any suitable manner. for example, by conventional spring hood clamps

(not shown). The hood 293 is provided with an opening 299 (Fig. 3) in the zone of the coupling

elements I99 and I19 and an opening 299 (Fig. 1) in the zone of the coupling elements 294 and

299, whereby to provide ready access to these couplings without requiring removal of said hood.

The instrument stand 8 comprises a cabinet 2I2 mounted upon legs 2" and 2I9 secured to cabinet

side walls H9 and 2, respectively. The lower portion of each of the legs H1 and 2I9 ,includes a

triangular section generally designated by the numeral 22I, the sides of the triangular portion

extending beyond the base of said triangular portion and being provided with casters 222 enabling

the instrument stand S to be readily moved from one location to another.

The cabinet 2I2 carries a bracket 229, Fig. i, which serves as a convenient mounting means for

the electrical remote control I91, previously described, for controlling the loading and unloading

valves I99 and I19, respectively. associated with the brake unit 13.

The present hydraulic brake unit B is designed to meet the testing requirements of vehicles of

average weight, so as to provide the widest possible field of eilicient use for the unit in service

stations, etc. However, in some instances it may be desirable to increase the capacity of the

dynamometer, or to conduct certain tests requiring more accurate compensation for the exact

weight of the vehicle, and this can be done by providing a flywheel and inertia weights (not shown)

which will increase the inertia of 'the brake shaft 59. Dynamometers including flywheels provided

with inertia weights are fully disclosed, and claimed, in a continuation-impartapplication Serial No.

775,768, filed September 24, 1947.

The portable type of dynamometer, which has been thus far described, has the advantage that it

can be set up for use in a comparatively short period of time, usually not more than about thirty

minutes. In order to set up the dynamometer for operation, it is usually necessary only to connect

the coupling I99 to a source of water supply L and the coupling I13 to a suitable drain D, to connect

the female coupling element 29I of the hose line 299 of the instrument stand to the male coupling

element 294 and to connect the male coupling element 214 of the hose line 213 to the female

coupling element 295. The use of the male and female couplings in the manner disclosed

prevents the hose lines 299 and 213 from being improperly connected. When the described

connections have been made, all of the necessary water and drain connections are complete.

The only necessary electrical connections that need be made can be made through a suitable

extension cord E (Fig. 4) having a plug adaptcd to be mounted in a receptacle box 493 secured

to the frame member 9 by bolts 494 to bring current to the dynamometer frame. The ramps 23,

of course, must be secured is t to the side member 3 of the main frame I by the screws'26 before

driving a-car onto the rolls Ill and II.

Once the dynamometer apparatus has been set up, the general procedure in preparing a motor

vehicle for test to determine faulty and/or malfunctioning parts of the engine and/or vehicle is to

back the vehicle onto the chassis dynamometer unit so that the rear wheels are cradled between

the rolls l and IL, The rear tires are inflated to the proper pressure and pawls 28 are checked to

see that they are disengaged from the ratchets 21. The chocks Y are placed in front of the front

wheels as a precautionary measure to prevent the vehicle from inadvertently leaving the rolls l0

and H, but with the present design normally the chocks are wholly unnecessary inasmuch as

there is no tendency whatever for the wheels to ride up on the rolls during a test, regardless of

the speed at which they are driven.

The valve 202 for controlling the flow of coolingwater through the heat exchanger I80 should also

be opened. The vehicle engine is then started in the conventional manner, the main clutch is

disengaged and the transmission is shifted into high gear. The main clutch is then engaged and

the rear wheels of the vehicle will now drive the dynamometer rolls i0 and H. Driving of the roll i I

will cause the rotor 14 of the brake unit B to turn at the-same speed.

The first-step in the actual testing of the engine is to open the loading valve I66 by depressing the

On" button lfit'of the remote control device I61. This may be done by the operator while seated

behind the steering wheel or while standing beside the vehicle. Opening of the valve I56, as

previously explained herein, admits water into the brake'housing 50 through the hose I05. As the,

water flows into the housing 50 a resistance is built up to absorb the power delivered by the

vehicle wheels to the dynamometer rolls l0 and l I. The vehicle can then be operated at any

desired speed and, depending upon the brake resistance, at any desired throttle opening.

However, in analytical work with the present dynamometer it is preferable to load the brake unit

B so that it will pull down the speed of the vehicle to 20 or 25 miles per hour at wide open throttle,

at which time the corresponding horsepower developed by the vehicle is noted from the

horsepower meter 35| and a record made thereof on a chart. If desired, readings of vacuum and

carburetor eiliciency can also be noted.

placed from the brake housing and circulated I through the closed cooling system, previously

described herein. including the heat exchanger I80 containing the small tubes I86 and I90 and

that a volume equal to that displaced will be continuovsly'returned to said housing by the action

of the rotor ll, so that there is no tendency for the brake liquid to seriously heat up during the tests

just described and, moreover, a desired constant volume of liquid is thus maintained in the brake

housing assuring a desired constant load.

It will also be understood that the heat exchanger 180 and the conduit means'connectlng the

same with the brake housing provide a circulating system for the brake liquid, arranged by way

of example exteriorly of the working circuit, which is normally closed to the atmosphere and

normally under pressures in excess of atmospheric pressure. It will be further understood that the

circulating system may possibly be considered to be open to the atmosphere during unloading, i.

e., at times when brake liquid is being drained from the system to reduce the torque absorption

capacity of the brake unit, but that in the normal use of the brake unit the brake liquid is confined

to' circulation in the closed system and cannot flow to the atmosphere or into an open tank or the

equivalent.

The next step in testing the engine preferably is to subject the engine to a predetermined indexing

load, or cruising load,by reducing the power absorption capacity of the dynamometer to a point

equal to the load that would be required to drive the test vehicle along a practically level road at

a predetermined speed. This indexing load may be taken, for convenience, as the load at which

the engine is developing 17 horsepower at a vehicle speed of 40 miles per hour. The necessary

loading of the brake unit B for these con ditions can be easily obtained by noting the speed and

horsepower meters350 and 355i and controlling the amount of water in the brake housing through

the remote control device I61. Once the desired cruising load has been placed upon the engine,

the load will remain constant inasmuch as no liquid can enter or leave the closed circulating

system of the brake unit without The next step in using the present dynamometer preferably is to

release'the load on the brake unit B by depressing the "Off button ill of the remote control I51 to

thereby actuate the unloading valve M6 to permit the water to be drained from the brake'housing

50 and thereby decrease the resistance offered by the brake unit B. The "05 button 811 is

maintained depressed until the vehicle speeds up to about 40 miles per hour with wide-open

throttle. whereupon the horsepower is again noted, and the vacuum readine and exhaust gases

again c ecked, if desired. These two tests are usually sufficient to determine the general condition

of the vehicle under severe duty, or wide-open throttle operation. It is usually under such cond

tions that any misfiring of the en ine, faulty valve operation. transmission and differential noises.

etc., may be noted by the operator for later correction or adjustment.

It will be understood that a portion of the liquid of the brake unit absorbing the power developed

by the engine will be continuously disfurther manipulation of the control device I61 by the operator.

The vehicle can then be operated at any speed from 10 to miles per hour by merely varying the

throttle opening. Speeds above 60 miles per hour at level road conditions may be obtained on the

dynamometer by a gradual decrease in the power absorption load of the dynamometer unit.

Again, for test purposes, it will be found sufflcient to test the vehicle at cruisine speeds

corresponding to those at which the vehicle was tested with wide-open throttle, namely. at 20 and

40 miles per hour, respectively. The horsepower developed at these speeds under cruisin

conditions can be noted from the horsepower meter 545i and tabulated on the chart. In addition.

the vacuum in the intake manifold can he recorded together with the exhaust gas analysis data.

Durin the tests under cruising load. it is po s ble to further detect malfunctioning parts of th motor

and drive mechanism.

The foregoing tests are those required for the vast majority of analytical work on the

dvnamometer. However. the operation of the dynamometer obviously is not restricted to these

speciflc tests. In some instances it is desirable to test the accelerating capacity of' the vehicle and

such acceleration tests may be conveniently made after the cruising load tests. For example,

at 60 miles per hour and the brake unit B loaded by depressing the "On" button I of the

remotecontrol, I" to load the brake and pull the vehicle down to a speed of 15 miles per hour at

wideopen throttle.

The loadingis left at this point by releasing the "On" button I" and the throttle opening is reduced

until the speed meter"! indicates a speed of 10 miles per hour. The throttle is then opened

simultaneously with theactuation of the unloading or "01! button ll! of the remote control so that

the brake unit B can unload. The brake unit is so designed that it will unload at a rate simulating

the normal acceleration rate of a vehicle on a levelroad. This feature of the dynamometer is

achieved by the restriction to the flow of the outlet liquid leaving the brake housing offered by the

solenoid valve I" which has a 55-inch orifice. During the unloading, interval that it takes the brake

unit 13 to unload and the acceleration capacity of the engine can be gauged from the behavior of

the engine and said time interval.

The data obtained from the foregoing tests are compared with standard performance ratings for

the particular vehicle tested to aid in determining when necessary adustments or replacements

are to be made, and in determining what part of the vehicle should be repaired or adjusted. Thus,

the prescribed dynamometer tests subject the parts of the engine and running gear to various

conditions of operation corresponding to their most severe road use. Hence, if faulty parts exist,

they will make themselves known to the operator during the test under which they are subjected

to their severest duty. The operator's knowledge enables him to determine what parts are

subjected to their severest duty during the various tests and to make such adjustments or repairs

as to place the parts in maximum operating efflciency. After the analysis has been made and the

difllculties corrected, final adjustments can be. made while the car is still 'on the dynamometer

and in actual operation so that it can be readily determined whether or not the parts have been

adjusted to develop their maximum or best performance by comparing the meter readings after

adjustments have been made with readings of similar tests made before said adjustments. It is

normally desired to test the engine on the fuel that will actually be used in the car and to adjust

the carburetor, spark, etc., for best operation under the altitude at which average driving is to take

place.

While the hydraulic brake unit B has been shown associated with a chassis dynamometer, it is to

be understood that the same can be mounted upon any suitable stand (not shown) and used in

making engine tests with the engine mounted upon any suitable block (not shown). Likewise, the

brake unit B is not limited to dynamometer use but can be used as a vehicle brake, as generally

described hereinbefore.

It will also be understood that various changes may be made in the, construction and arrangement

of the parts shown herein without departing from the spirit of the invention or the scope of the

appended claims.

I claim:

1. Load absorption means comprising: a hollow drum-like housing; a shaft rotatably mounted in

said housing; a rotor in said housing secured in said shaft, said housing having a hub the operator

can note the time portion on the interior thereof and a series of straight vanes arranged

s"bstantially tangential to said hub portion and extending from said hub portion to the periphery

of said housing forming a series of pockets between said vanes, said rotor having a hub portion

and a plurality of radially outwardly extending vanes forming a series of pockets confronting the

pockets of said housing; and means for admitting liquid into and for draining liquid from said

housing.

2. Torque absorption means comprising: a housing having opposed side walls and a Perlpheral

wall, each of said side walls having a central hub portion and a plurality of straight vanes extending

substantially tangentially from said hub portion to said peripheral wall; a. shaft rotatably mounted

in'the hub portions of said side walls; a rotor within said housing secured to said shaft, said rotor

comprising a hub portion, a .web extending centrally from said hub portion to a point adjacent

said peripheral wall and a series of vanes on each side of said web extending outwardly from said

hub portion to the periphery of said web; and means for admitting liquid into and for exhausting

liquid from said housing.

3. Torque absorption means comprising: a drum-like housing having opposed side walls and a.

peripheral wall, each of said side walls having a central hub portion and a plurality of straight

vanes extending substantially tangentially from said hub portion to said peripheral wall; a shaft

rotatably mounted in the hub portions of said side walls; a rotor within said housing secured to

said shaft, said rotor comprising a hub portion, a web extending centrally from said hub portion to

a point adjacent said peripheral wall and a series of vanes on each side of said web extending

radially outwardly from said hub portion but terminating short of said peripheral wall;

'and means for admitting liquid into and for exhausting liquid from said housing.

4. Means for absorbing power comprising: a drum-like housing having opposed side walls and a

peripheral wall, each of said side walls having a central hub portion and a plurality of vanes

extending from said hub portion to said peripheral wall, said peripheral wall having inwardly

projecting transverse webs staggered circumferentially with respect to said vanes; a shaft

rotatably mounted in the hub portions of said side walls; a rotor within said housing secured to

said shaft, said rotor comprising a hub portion, a web extending centrally from said hub portion to

a point adjacent the inner edge of said transverse webs and a series of vanes on each side of

said web extending outwardly from said hub portion; and means for admitting liquid into and for

exhausting liquid from said housing.

5. Means for absorbing power comprising: a drum-like housing having opposed side walls and a

peripheral wall, each of said side walls having a central hub portion and a plurality of vanes

extending from said hub portion to said peripheral wall and extending axially toward each other

from said side walls, but terminating with their inner edges in spaced relation to each other to

provide a series of pockets open at their inner sides for the full radial length of said vanes; a shaft

rotatably mounted in the hub portions of said side walls; a rotor within said housing secured to

said shaft, said rotor comprising a hub portion, a flat web of substantially uniform thickness

extending centrally from said hub portion to a point adjacent said peripheral wall and a series of

vanes on eachside of said web extend I ing outwardly from said hub portion to the outer periphery

of said web but terminating short of said peripheral wall, the number of vanes on the housing

being different from the number of vanes on-the rotor; whereby harmonic vibrations are

prevented; and means for. admitting fluid into and for exhausting fluid from said housing.

6..Means for absorbing power comprising: a drum-like housing having opposed side walls and a

peripheral wall, each of said side walls having a. central hub portion and a plurality of vanes

extending substantially tangentially from said hub portion to said peripheral wall; a shaft rotatably

mounted in the hub portions of .said side walls; a rotor within said housing secured to said shaft,

said rotor comprising a hub portion, a flat web of substantially uniform thickness extending

centrally from said hub portion to a point adjacent said peripheral wall and a series of vanes on

each side of said web extending substantially radially outwardly from said hub portion to the outer

periphery of said web but terminating short of said peripheral wall, the number of vanes on the

housing being different from the number of vanes on the rotor, whereby harmonic vibrations are

prevented; and means for admitting fluid into and for exhausting fluid from said housing.

'7. Means for absorbing power comprising: a drum-like housing having opposed side walls and a

peripheral wall, each of said side walls having a central hub portion and a plurality of vanes

extending substantially tangentially from said hub portion to said peripheral wall, said peripheral

wall having transverse webs extending inwardly therefrom between the vanes of said side walls;

a shaft rotatably mounted in the hub portions of said side walls; a rotor within said housing secured

to said shaft, said rotor comprising a hub portion, a web extending centrally from said hub portion

to a point adjacent the innermost edge of the transverse webs of said peripheral wall and a series

of vanes on each side of said web extending substantially radially outwardly from said hub portion

and terminating at the periphery of said central web, the number of vanes on said side walls being

difierent from the number of vanes on the rotor, whereby harmonic vibrations are prevented; and

means for admitting liquid into and for exhausting liquid from said housing.

8. Means for absorbing power comprising: a drum-like housing having opposed side walls, and a

peripheral wall of substantially uniform thickness, each of said side walls having a central hub

portion and a plurality of vanes extending outwardly from said hub portion to said peripheral wall

and extending axially toward each other with the edges of said vanes confronting each other in

spaced apart relation throughout their length; a shaft rotatably mounted in the hub portions of said

side walls; a rotor within said housing secured to said shaft. said rotor com-' prising a hub portion,

a web extending centrally from said hub portion between said vanes to a point adjacent said

peripheral wall and a series of vanes on each side of said web extending outwardly from said hub

portion to the outer periphery of said web but terminating short of said peripheral wall, the

outermost portions oi said housing vanes being of increased axial depth and being a maximum

at said peripheral wall, and the outermost portions of said rotor vanes being of reduced axial

depth; and means for admitting fluid into'and for exhausting fluid from said housing.

"9. Means for absorbing power comprising: a drum-like housing having opposed side walls and a

peripheral wall, each of said side walls having acentral hub portionand a plurality of vanes

extending from said hub portion to said peripheral wall, said peripheral wall-having transverse

webs extending inwardly therefrom between the vanes of said side walls: a shaft rotatably

mounted in the hub portions of said side walls; :a rotor within said housing secured to said shaft,

said rotor comprisinga hub portion, a web extending centrally from said hub portion to a point

adjacent the innermost edge of the transverse webs of said peripheral wall and a series ofvanes

on eachside of said web extending outwardly from said hub portion and terminating at the

periphery of said central web, the number of vanes on said side walls being different from the

number of vanes on the rotor, whereby harmonic vibrations are prevented; and means for

admitting liquid into and for exhausting liquid from said housing.

10. A power absorption device comprising: a closed housing havingopposed circular side walls

and a substantially cylindrical peripheral wall spacing said side walls apart, each of said side walls

having a central hub portion and a plurality of vanes extending outwardly from said hub portion to

said peripheral wall and extending axially toward each other, but with their inner edges terminating

in spaced relation to each other and providing a series of pockets on each side wall open at the

inner sides thereof for the full radial length of said vanes, a power absorption shaft rotatably

mounted in the hub portions of said side walls; a rotor secured to said shaft in said housing, said

rotor including a hub portion. a central radial web of uniform thickness and radially extending

vanes on the opposite sides of said web providing a plurality of pockets on each side of said web

confronting said peripheral wall and the pockets in said side walls, the total number of pockets in

said side walls being different from the total number of pockets in said rotor; check valve means

for venting said housing to the atmosphere; and means for admitting liquid into and for exhausting

liquid from said housing.

11. A liquid brake device comprising: a housing including two sections, each of said sections

comprising a central hub portion, a radially extending side wall and an axially extending peripheral

wall, the peripheral walls of said sections projecting toward each other and being secured together

in fluid-tight relation, each of said sections being provided with a series of internal vanes extending

tangentially from their respective hub portions toward their respective peripheral walls and also

having a series of internal webs carried by their peripheral walls with oneweb disposed between

each two adjacent tangential vanes; a shaft mounted in the hubs of said housing sections; a rotor

secured to said shaft between said housing sections, said rotor having a hub portion and a

plurality of series of vanes extending radially outwardly from said hub portion; and means for

admitting liquid into and for draining liquid from said housing.

12. Fluid brake means comprising: a housing having a substantially cylindrical peripheral wall and

opposed side walls, each of saidside walls having a hub portion formed interiorly of the housing

and having a series of vanes extending substantially tangentially from said hub portion to said

peripheral walland providing confronting pockets .open for the entire length of said vanes, the

outer portions of said tangential vanes being inclined along the inner edges thereof and extending

toward but terminating in spaced relation to'each other; a shaft rotatably mounted in the hub

portions of said side walls; a rotor secured to said shaft within said housing, said rotor having a

hubportion and a iiat central web of substantially uniform thickness extending outwardly from said

hub portion to a point in close proximity to the inner surface of the peripheral wall of said housing,

said rotor also having a plurality of vanes on the opposite sides of said central web, said vanes

extending radially outwardly from said hub to the outer peripheral portion of said web, the

outermost portions of the vanes of said rotor being of reduced axial width and including a portion

beveled outwardly and inwardly toward said web and being disposed in a zone opposite to the

inclined portions of the tangential vanes of said housing; and means for admitting liquid into and

for draining liquid from said housing.

13. A dynamometer comprising: a hydraulic brake unit for absorbing the power developed by

an'engine being tested, said brake unit including a housing adapted to contain water for use as a

brake liquid, a brake shaft *rotatably mounted in said housing, and a rotor within said housing

mounted upon said brake shaft; a heat exchanger having an inlet and an outlet; conduit means

connecting said inlet and outlet with said housing and establishing an uninterrupted flow path

between the interior of said housing and said heat exchanger normally under superatmospheric

pressure, said heat exchanger containing a plurality of tubes arranged so that the brake liquid in

traversing said heat exchanger must flow through said tubes, said rotor serving to cause forced

circulation of the brake llquidthrough said heat exchanger and conduit means in a manner to

return liquid from said heat exchanger to said housing at the same rate at which said rotor forces

liquid out of said housing and into said heat exchanger; a supply pipe for supplying water to said

housing to increase the load absorption capacity of said brake unit, said supply pipe having a

valve connected therein; and a drain pipe for discharging water to waste from said housing to

decrease the load absorption capacity of said brake unit, said drain pipe being connected with

said supply pipe at a point between said housing and said valve, said drain pipe having a valve

connected therein adjacent its point of connection with said supply pipe.

14. A dynamometer comprising: a hydraulic brake unit for absorbing the power developed by an

engine being tested, said brake unit including a housing adapted to contain water for use as a

brake liquid, a brake shaft rotatably mounted in said housing, and a rotor within said housing

mounted upon said brake shaft; a heat exchanger having an inlet and an outlet; conduit 'means

respectively connecting said inlet and outlet with said housing to form an endless circuit for said

brake liquid normally closed to the atmosphere, said heat exchanger containing a plurality of tubes

arranged so that the brake liquid in traversing said heat exchanger must flow through said tubes,

said rotor serving to cause forced circulation of the brake liquid from said housing at a given flow

rate and into and through said heat exchanger and back to, said housing at the same flow rate; a

supply pipe for supplying water to said housing to increase the load absorption capacity of said

brake unit. said su ply pipe having an electromagnetic loading valve connected therein: a drain

pipe for discharging water to waste from said housing to decrease the load absorption capacity

of said brake unit, said drain pipe being connected with said supply pipe at a point between said

housing and said valve, said drain pipe having an electromagnetic unloading valve connected

therein adjacent its point ofconnectlon with said supply pipe; and remote control means for

controlling the operation of said valves.

15. A dynamometer comprising: a hydraulic brake unit for absorbing the power developed by an

engine being tested, said brake unit including a housing adapted to contain water for use as a

brake liquid, a brake shaft rotatably mounted in said housing, and a rotor within said housing

mounted upon said brake shaft; a heat exchanger having an inlet and an outlet; conduit means

connecting said inlet and outlet with said housing and forming a circulating system for the brake

liquid normally-under superatmospheric pressure, said heat exchanger containing a plurality of

tubes arranged so that the brake liquid in traversing said heat exchanger must flow through said

tubes, said rotor serving to cause forced circulation of the brake liquid through said heat

exchanger; 9. supply pipe for supplying water to said housing to increase the load absorption

capacity of said brake unit, said supply pipe having a loading valve connected therein; a drain

pipe for discharging water to waste from said housing to decrease the load absorption capacity

of said brake unit, said drain pipe being connected with said supply pipe at a point between said

housing and said valve, said drain pipe having an unloading valve connected therein adjacent its

point of connection with said supply pipe; means for admitting cooling water to said heat

exchanger for contact with the exterior of said tubes including a conduit connecting said heat

exchanger with said supply pipe at a point ahead of said loading valve; and means for discharging

cooling water from said heat exchanger including a conduit connected to said drain pipe at a point

on the discharge side of said unloading valve.

16. A device for absorbing the power of a driven member, comprising: a hydraulic brake unit

including a housing adapted to contain any given volume of brake liquid within its capacity, and a

rotor in said housing adapted to be connected with said driven member, said housing and rotor

having vanes cooperable to form a working circuit for said brake liquid;'means for varying the

volume of brake liquid in said working circuit at will to vary the load absorption capacity of said

brake unit; a heat exchanger having an inlet and an outlet and normally being full of brake liquid;

means having a passage establishing communication between the working circuit of said

hydraulic brake unit and the inlet and outlet,

respectively, of said heat exchanger, said last-' mentioned means also normally being full of brake

liquid, whereby to provide a closed circulatng and cooling system for the brake liquid normally

closed to the atmosphere in which any given volume of brake liquid displaced from said working

circuit by said rotor and forced by said rotor into said heat exchanger is simultaneously replaced

by an equal volume of brake liquid formed out of said heat exchanger by the action of said rotor

and returned to said working circuit, so that a constant volume of brake liquid is maintained in

said work ng circut for any given load regardless of the speed of the rotor.

17. A device for absorbing the power of a driven member, comprising: a hydraulic brake unit

inassasso 21 eluding a stator adapted to contain any given volume of brake liquid within its

capacity, and a rotor in said stator adapted to be connected with said driven member, said stator

and rotor havin means cooperable to form a working circuit for said brake liquid; a heat exchanger

having inlet and outlet means in open communication with the working circuit in the interior of said

stator and normally being filled with brake liquid, said rotor being adapted, as it is rotated, to

positively displace brake liquid from said working circuit, force the displaced brake liquid into and

through said heat exchanger, and back into said working circuit, whereby to provide a closed

circulating and cooling system for the brake liquid normally operating under superatmospheric

pressure and in which any given volume of brake liquid dis- I continuously force brake liquid out

or said workplaced from said working circuit by said rotor and forced into said heat exchanger is

simultaneously replaced by an equal volume of brake liquid forced out of said heat exchanger

and returned to said working circuit, so that a constant volume of brake liquid is maintained in

said stator for any given load regardless of the speed of the rotor.

18. A device for absorbing the energy of a driven member, comprising: a hydraulic brake unit

including a stator adapted to contain brake liquid, and a rotor in said stator adapted to be

connected with said driven member, said stator and rotor having means forming a working circuit

for said brake liquid; a heat exchanger for cooling said brake liquid, said heat exchanger having

inlet and outlet means for said brake liquid; and passage means having a substantially uniform

cross-sectional area interconnecting said working circuit and said inlet and outlet means of said

heat exchanger and cooperable therewith to provide an interrupted circulating system for said

brake liquid normally closed to the atmosphere, said rotor serving to chest iorced circulation of

said brake liquid by continuously forcing a given volume of said brake liquid from said working

circuit, into said heat exchanger and continuously forcing an equal volume oi said brake liquid out

of said heat exchanger and back into said working circuit, whereby the volume of brake liquid in

said working circuit is maintained constant.

19. A device for absorbing the energy of a driven member, comprising: a hydraulic brake unit

including a stator adapted to contain a brake liquid, and a rotor in said stator adapted to be

connected with said driven member, said stator and rotor having means providing a working circuit

for said brake liquid; and means including a heat exchanger communicating with said working

circuit at diflerent points and providing a continuous, uninterrupted flow path for brake liquid

exteriorly of said working circuit, said flow path being completely filled with brake liquid under

hydraulic pressure normally above atmospheric pressure when said brake unit is in operation,

said rotor serving as an impeller when rotating to continuously force brake liquid out of said

working circuit into and through said flow path including said heat exchanger, and back into said

working circuit, whereby the volume of brake liquid in said working circuit is maintained constant

regardless of the speed of said rotor.

20. A device for absorbing the energy or a driven member, comprising: a hydraulic brake unit

including a stator adapted to contain a brake liquid, and a rotor in said stator adapted to be

connected with said driven member, said'stator ing circuit into and through said flow path including

said heat exchanger, and back into said working circuit, whereby the volume of brake liquid in

said working circuit is maintained constant regardless of the speed oi said rotor:- and means

operable at will to vary the volume of brake liquid in said working circuit to change the load

absorption capacity or said'brake unit as desired.

21. A device for absorbing the energy of a driven member, comprising: a hydraulic brake unit

including a stator adapted to contain brake liquid, and a rotor in said stator adapted to be

connected with said driven member, said stator having an inlet opening and an outlet opening' for

brake liquid, and said stator and rotor having means forming a working circuit for said brake liquid;

a heat exchanger for cooling said brake liquid, said heat exchanger having an inlet and an outlet

for said brake liquid; a conduit connected at one end to said outlet opening of said stator and

connected at its opposite end with said inlet or said heat exchanger; and another conduit

connected at one end with said outlet of said heat exchanger and connected at its opposite end

to, said inlet opening of said stator, whereby said conduits are cooperable with said stator and

heat exchanger to provide an uninterrupted circulating system iorsaid brake liquid normally

maintained under superatmospheric pressure.

22.- A device for absorbing the energy of a driven member, comprising: a hydraulic brake unit

including a stator adapted to contain brake liquid, and a rotor in said stator adapted to be

connected with said driven member, said stator having an inlet opening and an outlet opening

connected at its opposite end with said inlet of said heat exchanger; another conduit means

connected at one end with said outlet 0! said heat exchanger and connected at its opposite end

to said inlet opening of said stator, whereby said conduit means are cooperable with said stator

and heat exchanger to provide a closed, uninterrupted circulating system for said brake liquid and

means for varying at will the volume of brake liquid in said system to change the load absorption

capacity of said brake unit.

23. A device as defined in claim 22, in which the means operable at will for varying the volume of

brake liquid in the closed system comprises, a manually operable loading valve and a manually

operable unloading valve arranged to admit brake liquid into said system and to drain brake liquid

from said system, respectively.

24. A device'as defined in claim 22, in which the means operable at will for varying the volume of

brake liquid in the closed system comprises, a loading valve and an unloading valve arranged for

admitting brake liquid into said system andfor draining brake liquid from said system,

respectively;. and a manually operable remote control device connected'with said valves for

controlling the operation thereof.

25. A device as defined in claim 22, in which the means operable at will for varying the volume of

brake liquid in the closed system comprises, an electromagnetic loading valve for admitting brake

liquid into said system and an electromagnetic unloading valve for draining brake liquid from said

system and a remotecontrol device connected with said electromagnetic valves'and including two

switches, one for eflecting opening of each of said valves. a

' 26.1A device as defined in claim 22, in which the means operable at will for varying the volume

of brake liquid in the closed system comprises, an electromagnetic loading valve for admitting

brake liquid, into said system and an electromagnetic, unloading valve for draining brake liquid

from said system; and a portable remote control device connected with said electromagnetic

valves and adapted to be held in the hand of the operator, said remote control device including

two switches, one for effecting opening of each of said valves;

27. A device for absorbing the energy of a drivenn ember, comprising: a hydraulic brake unit

including a stator adapted to contain a brakeliquid, and'a rotor in said stator adapted to be

connected withsaid driven] member, said stator having an outlet and an inlet; and means

includinga heat exchanger for cooling said brake liquid connecting said outlet with; said inlet and

providing an uninterrupted fiowjpath of fixed volume for brake liquid exteriorly, of said stator, said

fiow path being completely filled with a continuous stream of brake liquid under hydraulic pressure

normally above atmospheric pressure when said, brake unit is in operation, said 'rotor serving as

an impeller when rotating to continuously force brake liquid out of said stator at a given rate into

and through said flow path including'said heat exchanger, and back into said stator at the same

rate, whereby the volume of brake liquid in said stator is maintained constant regardless of the

speed of said rotor.

28. Adevice for absorbingthe energy of a driven member, comprising: a hydraulic brake unit

including a stator adapted to contain a brake liquid, and a rotor in said stator adapted to be

connected with said driven member, said stator having an outlet and an inlet; means including a

heat exchanger for cooling said brake liquid connecting said outlet with said inlet and providing

an uninterrupted flow path of fixed vol-. ume for brake liquid exterior-1y of said stator, said flow

path being completely filled with a continuous stream of brake liquid under hydraulic pressure

normally above atmospheric pressure when said brake unit .is in operation, said rotor serving as

an impeller whenrotating to continuously force brake liquid out of said stator at a given rate into

and through said flow path including said heat exchanger, and back into said stator at the same

rate, whereby the volume of brake liquid in said stator is maintained constant regardless of the

speed of said rotor; and means operable at will to vary the volume of brake liquid available for

circulation by said rotor to change the load absorption capacity of said brake unit as desired.

29. In combination, a devicefor absorbing the 24 energy of a rotating'element, comprising: a drum-

likestator adapted to contain a liquid, saidstator having a central hub portion, a shaft rotatably

mounted in said hub portion and adapted to be connected with said rotating e1e-,

. ment, and a rotor in said stator secured to said shaft; a heat'exchanger for cooling the liquid of

saidenergy absorption device, said heat exchanger havingan inlet and an outlet for, said liquid;

and a pair of conduits interconnecting'said energy absorption device and said heat exchanger for

circulation of said brake liquid through said heat exchanger, by said rotor, one of said conduits

connebtingsaid inlet of said heat exchanger with said stator and communicating with the interior

of said stator at a point adjacent the periphery thereof and theother of said conduits connecting

said 'outletof said heat exchange? with said stator and communicating with the interior of said

stator at a point adjacent thehub portion thereof, said conduits and. heat exchanger normallybeing

closed to the atmosphere.

30. Ir comblnation, a device for absorbing the energy of a rotating element, comprising; a drum-

like casing adapted .to contain a liquid, said casing having a central hub portion, a shaft rotatably

mounted in said hub portion and adapted to be connected with said rotating element, and a rotor

in said casing secured to said shaft; a heat exchanger for cooling the liquid of said energy

absorption device, said heat exchanger liavingan inlet and an outlet for said liquid; 9. pair of

conduits interconnecting said energy absorption device and said heat exchanger arranged to form

a circulating system normally closed to the atmosphere, one of said conduits connecting said inlet

of said heat exchanger with the interior of said casing adjacent the periphery thereof and the other

of said conduitsconnecting said outlet of said heat exchanger with the interior of said casing

adjacent the hub portion thereof; and means for controlling and varying the volume of liquid in

said system, whereby to maintain the capacity of said energy absorption device constant or to

vary the same,

, as desired.

31. The method of absorbing the torque of a rotating element, comprising the steps of: introducing

a sufiicient volume of brake liquid into a low pressure area of the working circuit of a hydraulic

brake to impose a desired load upon said rotating element; eflecting the withdrawal of brake liquid

from a relatively high pressure.

area of said working circuit at a given rate; circulating the withdrawn brake liquid through a system

normally closed to the atmosphere but in direct communication with said areas; cooling the brake

liquid while it is circulating through said system; and returning the cooled brake liquid from said

system to said ,working circuit at a rate equal to that at which it is being withdrawn from said

working circuit, whereby to maintain a constant volume of brake liquid in said working circuit and

a constant load upon said rotating element.

32. The method as defined in claim 31, including the step of circulating the withdrawn brake liquid

through the closed system under hydraulic pressure above atmospheric pressure.

33. The method as defined in claim 31, including the step of varying, at will, the total volume of

brake liquid to be circulated through said system to vary the load imposed upon the rotating

clement.

34. The method of absorbing the torque of a 25 rotating element, comprising the steps of:

introducing a suilicient volume of brake liquid into the working circuit of a hydraulic brake to

impose-a desired load upon said rotating element; effecting the withdrawal of brake liquid from

said working circuit at a given rate; circulating the withdrawn brake liquid through a system having

an inlet and an outlet communicating directly with said working circuit and being under hydraulic

pressure above atmospheric pressure; cooling the brake liquid while it is circulating through said

system; and returning cooled brake liquid to said working circuit at a rate equal to that at which it

is .being withdrawn from said working circuit, whereby to maintain a constant volume of brake

liquid in said working circuit and a constant load upon said rotating element.

35. The method of absorbing the torque of a rotating element, comprising the steps of: introducing

a suflicient volume of brake liquid into the working circuit of a hydraulic brake to impose a desired

load upon said rotating element;

effecting the flow of brake liquid from said working circuit at a given rate, directly into the inlet of

an uninterrupted flow system normally maintained under superatmospheric pressure while

preventing flow of the brake liquid to the atmosphere; circulating the brake liquid through said

system; cooling the brake liquid while it is circulating through said system; and returning cooled

brake liquid from the outlet of said system to said working circuit at a rate equal to that at which it

is being withdrawn therefrom, whereby to maintain a constant volume of brake liquid in said

working circuit and a constant load upon said rotating element.

36. The method of absorbing the torque of a rotating element, comprising the steps of: introducing

a sufllcient volume of brake liquid into the working circuit of a hydraulic rotor-type brake to impose

a desired load upon said rotating element; utilizing the impelling action of the rotor to continuously

displace brake liquid from said working circuit at a given rate and to force the same through a

zone normally closed to the atmosphere and back into said working circuit at a rate equal to that

at which the brake liquid is displaced from said working circuit, whereby to maintain a constant

volume of brake liquid in said working ciicuit and a constant load upon said rotating element; and

cooling the brake liquld while it is circulating through said zone.

37. The method of absorbing the torque of a rotating element, comprising the steps of: introducing

a suilicient volume of brake liquid into the working circuit of a hydraulic rotor-type brake to impose

a desired load upon said rotating element; utilizing the impelling action of the rotor to continuously

displace brake liquid from said working circuit at a given rate and to force the same through a

zone normally maintained under superatmospheric pressure, while preventing flow oi the brake

liquid to the atmosphere, and back into said working circuit at a rate equal to that at which the

brake liquid is displaced from said working circuit, whereby to maintain a constant volume of brake

liquid in said working circuit and a constant load upon said rotating element; and cooling the brake

liquid while it is circulating through said zone.

' 38. The method of absorbing the torque of a rotating element, comprising the steps of:

introducing a sumcient volume of brake liquid into a low pressure zone of the working circuit of a

hydraulic brake to impose a desired load upon said rotatig element; eifectlng the withdrawal of

brake liquid from a relatively high pressure zone of said working circuit at a given rate; conducting

the withdrawn brake liquid in the form of a continuous stream from said high pressure zone

through a predetermined flow path; cooling the brake liquid while it is circulating through said

path; and returning cooled brake liquid-to said working circuit at a rate equal to that at which it is

being withdrawn therefrom. whereby to maintain a constant volume of brake liquid in said working

circuit and a constant load upon said rotating element.

39. A dynamometer, comprising: a hydraulic brake unit for absorbing power developed by an

engine being tested, said brake unit including a housing adapted to contain water for use as a

brake liquid, a brake shaft rotatably mounted in said housing, and a rotor within said housing

mounted upon said brake shaft; a heat exchanger having an inlet and an outlet for said brake

liquid; conduit means connecting the respective ends of said heat exchanger with said housing

and providing a closed circulating system for the brake liquid normally closed to the atmosphere,

said heat exchanger containing a plurality of tubes arranged so that the brake liquid in traversing

said heat exchanger must flow through said tubes, said rotor serving to cause forced circulation

of the brake liquid from said housing at a given flow rate and into and through said heat exchanger

and back into said housing at the same flow rate; supply pipe means for supplying cooling water

to said heat exchanger and for supplying water to said brake unit housing; drain pipe means for

discharging the cooling water to waste after it has passed through said heat exchanger and for

discharging water from said housing to waste; a valve arranged in said supply pipe means to

control the admission of water into said brake housing to increase the load absorption capacity of

said brake unit; and a valve arranged in said drain pipe means for controlling the discharge of

water from said brake housing to decrease the load absorption capacity of said brake unit.

40. A dynamometer, comprising: a hydraulic brake unit for absorbing the power developed by an

engine being tested, said brake unit including a housing adapted to contain a brake liquid, a brake

shaft rotatably mounted in said housing, and a rotor within said housing mounted upon said brake

shaft; a heat exchanger having an inlet and an outlet; conduit means connecting said inlet and

outlet with said housing and establishing an uninterrupted flow path between the interior of said

housing and said heat exchanger normally under superatmospheric pressure when in use, said

rotor serving to cause forced circulation of the brake liquid through said heat exchanger and

conduit means in a manner to return brake liquid from said heat exchanger to said housing at the

same rate at which said rotor forces brake liquid out of said housing and into said heat exchanger;

a supply pipe for supplying brake liquid to said housing to increase the load absorption capacity

of said brake unit, said supply pipe having a valve connected therein; and a drain pipe for

discharging brake liquid from said housing to decrease the load absorption capactiy of said brake

unit, said drain pipe being connected with said supply pipe at a point between said housing and

said valve, said. drain pipe having a valve connected therein adjacent its point of connection with

said supply pipe.

41. A dynamometer, comprising: a hydraulic brake unit for absorbing the power developed by an

engine being tested, said brake unit includin a housing adapted to contain a brake liquid, a brake

shaft rotatably mounted in said housing. and a rotor within said housing mounted upon said brake

shaft; a heat exchanger having an inlet header, an outlet header, a return flow manifold, a pipe

connecting said inlet header with said manifold, another pipe connecting said outlet header with

said manifold, and a plurality of tubes in each of said pipes interconnecting said headers and

manifold; conduit means connecting said inlet and outlet headers with said housing and

establishing an uninterrupted flow path between the interior of said housing and said heat

exchanger normally under superatmospheric pressure when in use, said rotor serving to cause

forced circulation of the brake liquid through said heat exchanger and conduit means in a manner

.to return brake liquid from said heat exchanger to said housing at the same rate at which said

rotor forces brake liquid out of said housing and into said heat exchanger; a supply pipe for

supplying brake liquid to said housing to increase the load absorption capacity of said brake unit,

said supply pipe having a'valve connected therein; and a drain pipe for discharging brake liquid

from said housing to decrease the load absorption capacity of said brake unit, said drain pipe

being connected with said supply pipe at a point between said housing and said valve, said drain

pipe having a valve connected therein adjacent its point of connection with said supply pipe.

EDWIN L CLINE.

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Number Country Date 11,267 Great Britain 1911 361,587 Great Britain Nov. 26, 1931 OTHER

REFERENCES Pages 22, 23, 34 and 35 of Dynamometers-' Fraude and Keenan-Fell, catalogue

No. S /1, Dec. 1927 published by Heenan 8: Fraude Ltd., Worcester, England.