Important Features for

Utility Tractors

Herb Willcutt

MSU Ag & Bio Engineering

11/15/06

Goals

• Better understand utility tractor terminology used by manufacturers, sales reps and farmers

• Discuss utility tractor features important for accessibility

Transmissions (in order of $$$)

• Gear or collar shift

• Quick/Power reverser

• Sync Shuttle Shift

• Hydrostatic (Compact tractors under 50 hp)

• Power Quad (power shift within range)

• Power shift (larger tractors)

• IVT (Infinitely Variable Transmission)

Range Control• Most transmissions have 2 or 3 ranges with 3 to 5

“gears” in each range.• I.e. 3 ranges with 4 gears + reverse in each range

provides 12 forward speeds and three reverse speeds.• Ranges usually indicated• as “A”, “B” or “C”• Ranges are used with • other transmission types • for speed flexibility

Gear transmission• Clutch used for speed

or direction changes• Least expensive • Least productive

in loader operations• Usually limited in

speed ranges

Quick/Power Reverse

• Ease of changing from forward to reverse

• Must use clutch to change speed or direction

• Must be stopped to change speed or direction

Synchronized Shuttle Shift

• Provides shifting speeds without fully stopping

Hydrostatic

• Compact tractors under 50 hp

• Infinite speed and direction control– Great for loaders, slow speed operations and

wide range of speeds such as mowing

• Single or dual pedal operated

• Cruise feature to lock speed (release with brake or cruise switch)

Power Quad

• Bump lever control of speed and direction

• Clutch necessary for starting (safety) and range control only

• Each gear change will result in slight “jerk” as speed changes for a constant engine rpm

Full Power Shift

• All speeds and reverse are shifted with hydraulic clutch packs

• Bump lever control

• Forward to reverse without clucthing

• Slight “jerk” for each speed setting change

• Clutch necessary only for starting safety

• Usually an option only on larger tractors

IVT (Infinitely Variable Transmission)

• Infinite transmission speeds form 0 mph to max speed

• Dial in speed setting • European design (and primary use)• Combines hydrostatic and planetary gears

with computer control for smooth “jerk free” and efficient speed control to match the job

Remote Hydraulics• One or two rear valves

– Mechanical actuated with lever

– Electrical actuated with solenoid

• Joystick (loader control)• Placement of controls

– Joystick valves may block right entrance and egress (especially add on loader valves)

PTO (Power Take Off)

• 540 RPM standard at an engine speed• Independent

– Lever to engage shifted with clutch– PTO controlled by hydraulic clutch pack

• Semi independent – Push clutch to control the PTO– Common with hydrostatic transmissions

• Two stage clutch– Push down half way to change gears, all the way to disengage

the PTO– Found on older tractors

Hitches

• Three point – Fixed lower

links– Telescoping

lower links– Quick

hitches

Fixed Drawbar

Lower Link Stabilizer

Parking Brake Actuation

• Push pedal/pull latch

• Automotive lever

• Transmission lock position

Differential Lock

• Locks all drive wheels together

• If one drive wheel slips other side will not stop pulling

• Engaged on the go by depressing a pedal with a heal

• Releases when axle torque on each side returns to near equal

Front Wheel Assist• Provides power to all 4

wheels• Decreases rolling resistance

of front wheels• May increase turning

radius slightly• Better handling, traction

and stability• Superior performance for

loaders where weight shifts from full to empty bucket

• May increase the operator platform height because of tire sizes

Operator Platforms

• Open, two post ROPS

• Open, two post ROPS with canopy– Canopy may limit access height for lifts or

for a person who cannot bend easily

• Four Post ROPS– May limit access

• Cab

Operator Platforms• Flat deck• Straddle mount/Isolated

open• Steps

– Rigid and flex– Step height– Right vs. left cab entrance &

egress

Steering• Power vs manual steering

– Most late model tractors will have power steering even on smaller tractors

• Tilt, telescoping and fixed steering shaft– Tilt & telescope provides greater access– Operator comfort once in seat

Tire Types

R1 Agricultural, Max traction in soft soil

R4 Industrial, loaders, mowers, firm soil stiff sidewalls & ride

R3 Turf, smooth ride

Loader Attachment Methods

Conclusion

• There are many features offered on utility tractors that affect performance, productivity, ease of control, access and price.

• Choose wisely to match the tractor, options, the job and the operator’s abilities for best performance.