DESIGN AND FABRICATION OF HYDRAULIC SCISSOR LIFT Mohd. Shivali1 , Lal Mohan Bind2 , Anand Prakash Yadav3 Savindra

Kumar Vaghela4 Prof. Manoj Kumar Solanki5

1, 2,3,4 ME Final Year Students, 5 Associate Professor

Krishna Engineering College ,Mohan Nagar

ABSTRACT

The following paper describes the design as well as analysis of a hydraulic scissor lifthaving two levels. Conventionally a scissor lift or jack is used for lifting a vehicle tochange a tire, to gain access to go to the underside of the vehicle, to lift the body toappreciable height, and many other applications .A Scissor lift is the type platform thatcan usually move vertically. This mechanism is achieved by the use of link, foldingsupport in crisscross pattern known as a Pantograph. The upward motion is achieved by theapplication of pressure to outside of the lowest set of support elongating the crossingpattern and propelling the work platform vertically. This paper describes the completestudy of components (Hydraulic cylinder, scissor arms, spacing shaft and platform),selection of materials and analyze the dimensions of components along with their sketcheswith the help of design software CATIA V5 followed by stress analysis on COMSOL. Furtherfabrication of all the parts and assembly is carried out . This technology is urgentlyneeded to increase the efficiency of lifting load and to reduce the complexity ofconstruction work. A Scissor lift is used for Arial works in industries, used formaintenance at high altitude. The design described in the paper is developed keeping inmind that the lift can be operated by mechanical means so that the overall cost of thescissor lift is reduced. Also such design can make and much suitable for medium the liftmore compact scale work.

Keywords: Hydraulic scissor lift; Pantograph; Hydraulic cylinder; Trusses; Von Misses stress.

1. Introduction: A scissor lift is a type of platform which moves in verticaldirection. The mechanism incorporated to achieve this function is the use oflinked, folding supports in a criss-cross 'X' pattern, known as a pantograph. Theupward motion is achieved by the application of pressure to the outside of thelowest set of supports, elongating the crossing pattern, and propelling the workplatform vertically upwards. The platform may also have an extending 'bridge' toallow closer access to the work area (because of the inherent limits of onlyvertical movement). The operation of the scissor action can be obtained byhydraulic, pneumatic or mechanical means (via a lead screw or rack and pinionsystem). Depending on the power system employed on the lift, it may require nopower to enter 'descent' mode, but rather a simple release of hydraulic orpneumatic pressure. This is the main reason that these methods of powering the

lifts are preferred, as it allows a fail-safe option of returning the platform tothe ground by release of a manual valve. It enables access to elevated work areasby raising a deck with a scissor mechanism. Scissor lift are widely used inconstruction industries, used for maintenance at high altitude.

Figure 1

2. Methods

2.1 Material selection Material selection is an important aspect in designing and manufacturingscissor lift. All the components are made of different component havingdifferent tensile strength and properties.

S.NO Components Material1. Upper platform Mild steel

2. Scissor arms Mild steel3. Spacing shaft Silver steel4. Lower platform Mild steel

2.1.1 Upper platform (Mild Steel)Mild steel is ductile material having high yield strength. Mild steel isone of the common of all metals and one of the least expensive steelused. It is used in manufacturing industries because of followingproperties:-

Least expensive Highly ductile Contains .05-.015% of carbon Tensile strength =240 Mpa Easily weldable Surface hardness can be increased by carburising. High machinability Easily available

UPPER PLATFORM

LOWER PLATFORM

SCISSOR ARM

HYDRAULIC CYLINDERSLOT

Principal alloying elements by weight are :- carbon (0.16%) ,Silicon(0.03%), copper(0.01%), nickel(0.01%),chromium(0.01%),manganese (0.32%) and iron .

2.1.2 Spacing shaft (silver steel)

hand tools. silver steel or high-carbon bright steel are used toproduce knives ,razor ,drill bits

Composition: carbon (1%), chromium(0.4%),manganese(0.35%), silcon(0.3%).

Properties of silver steel:-

very high wear resistance high machinability brittle in nature

3. Design: The parts of the scissor lift are drafted on CATIA V5 .

3.1 Design of upper platform

Figure 2 Dimension of upper platform (All dimension in mm)

3.2 Design of scissor arm

510

180

7 0 Φ 15 5 0

Figure 3 Dimension of scissor arm(All dimension in mm)

SPECIFICATIONStrength = 314mpaC. S area= 100 mm2

Maximum force= 31400 NActing force= 62.872 NFOS= 31400/62.872 = 499

3.3 Design of spacing shaft

Figure 4 Dimension ofspacing shaft (Alldimension in mm)

Specification of spacing shaft

Strength=540mpaArea = πd2/4= 113.97 mm2

Maximum force= 61072.38NActing force = 206.01N FOS= 61072.38/206.01 = 246.45

Specification of actuating rod

25

4101

10

80

185

15

33 Φ 12

Strength= 540 mpa Area = πd2/4 = 78.53 mm2

Maximum force = 42406.2 N Acting force = 414.69 N FOS = 102.26

Specification of hydraulic cylinder

Maximum pressure = 1 N/mm2

4. Calculation and Analysis

4.1 Reaction forces in members

F1 35.92N TensileF2 35.92N TensileF3 50.897N CompressiveF4 50.897N CompressiveF5 50.897N Tensile

A B

C

D E

F

G H

W/4 W/4

F1 F2

F3F4

F5 F6

F7 F8

83.385N

103.005N

F6 50.897N TensileF7 68.872N CompressiveF8 68.872N Compressive

4.2 Assembly of scissor lift designed on CATIA V5

Figure 5

5. Result Of Analysis

S.NO1. Maximum height 830 mm2. Maximum load 12-15 kg3. Maximum force

acting on arm68.872 N

4. Maximumactuating force

414.69 N

5. Factor of safety 2.01

5.1 Analysis of upper platform

6. Fabrication Process

6.1 Fabrication of upper platform and lower platform;- First of all mildsteel sheet of thickness 4mm is fabricated of dimension (510x420) with the helpof grinder , then it is bent with help of hydraulic press . secondly slots weremade in the bent portion at both sides along with hole of dia 1.5 mm. 6.2 Fabrication of scissor arm :- for this stripes were fabricated ofdimension (410x25x4) after that hole were drilled using drilling machine andfinally the stripes were filed.

6.3 Fabrication of spacing shaft: - For this rods of silver steel of length330mm and diameter (12mm) were prepared by parting operation on lathe. Secondlyrods were grooved at specified point with help of grooving operation performedon lathe.

7. Conclusion

This paper describes the complete study of design and analysis of hydraulicscissor lift for two level.With such a design of an hydraulic scissor lift, thecomplexities in the design can be reduced. Also with such design parameters, themanufacturing time of an aerial scissor lift can be reduced. So such a design canbe used for production in industries. The analysis on COMSOL has also shown thatthe design is safe under certain accepted parameters. Also further modificationscan be implemented for optimizing the design and further analysis can also becarried out by finding other important parameters related to aerial

References:

[1] US PATENT ,patent no. 5722513,inventor Richard T Rowan.

[2] Mathematical analysis of scissor lift, a technical document by H.M Spackman.

[3] US PATENT , patent no. 3785462, inventor George L. Coad.

[4] [5] Callister William D., “Material Science and Engineering: An Introduction” eighth edition, John Wiley & Sons Inc.

[6] Rao PN, “Manufacturing Technology” Volume-1 Second edition, Mc Graw- Hill Publication 2003.

[7] Rao PN, “Manufacturing Technology” Volume-2 Second edition, Mc Graw- Hill Publication 2011.

[8] Rattan SS, “Strength of Materials” (Second edition), Mc Graw- Hill Publication 2013.

[9] Bhandari VB, “Design of Machine Elements” (Third edition).Mc Graw -Hill Publication 2013.

[10] K. Mahadevan, K. Balaveera Reddy. “Design Data Hand Book” (third edition). CBS Publishers & Distributers Pvt. Ltd. 2011.

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