ELEVATOR FOR UPPER BERTH IN TRAINS

(1)

Volume 4, Special Issue 1, NCIAR2k17

66

Available online at www.ijiere.com

International Journal of Innovative and Emerging

Research in Engineering

e-ISSN: 2394 – 3343 p-ISSN: 2394 – 5494

ELEVATOR FOR UPPER BERTH IN TRAINS

a

_{Aravind M,}

b

_{Sibianandh R.G,}

b

_{Murali S,}

b

_{Yesvanthraj M,}

b

_{Kowsik R,}

a_Professor,b_{UG Students, Department of Mechatronics Engineering,}

Sri Krishna College of Engineering and Technology,Coimbatore, Tamilnadu

ABSTRACT:

A scissor lift or mechanism is a device used to extend or position a platform by mechanical means. The term “scissor” comes from the mechanic which has folding supports in criss cross “X” pattern. The extension or displacement motion is achieved by the application of force to one or more supports, resulting in an elongation of the cross pattern. The force applied to extend the scissors mechanism may by hydraulic, pneumatic or mechanical (via a lead screw or rack and pinion system). The need for the use of lift is very paramount and it runs across labs, workshops, factories, residential/commercial buildings to repair street lights, fixing of bill boards, electric bulbs etc. expanded and less-efficient, the engineers may run into one or more problems when in use. The paper explains the design of portable lift using scissor lift.

Keywords:Scissor lift ,Mobile elevating platform , Stable scissor lift

I. INTRODUCTION

The name scissors lift originated from the ability of the device to open (expand) and close (contract) just like a scissors. Considering the need for this kind of mechanism, estimating as well the cost of expanding energy more that result gotten as well the maintenance etc. it is better to adopt this design concept to the production of the machine.

The initial idea of design considered was the design of a single hydraulic ram for heavy duty vehicles and putting it underneath, but this has limitations as to the height and stability, and someone will be beneath controlling it. It was rather found out that; there is a possibility of the individual ascending/descending, to be controlling the device himself. Therefore further research was made to see how to achieve this aim.

Before this time scissors lift existing use mechanical or hydraulic system powered by batteries for its operations. Several challenges were encountered in this very design. Some amongst many include; low efficiency, risk of having the batteries discharged during an emergency, extended time of operation, dependent operation, as well as maintenance cost. It is the consideration of these factors that initiated the idea of producing this hydraulically powered scissors lift with independent operator. The idea is geared towards producing a scissors lift using one hydraulic ram placed across flat, in between two cross frames and powered by a pump connected to a motor wheel may be powered by a pump generator. Also, the individual ascending / descending is still the same person controlling it. I.e. the control station will be located on the top frame.

Most importantly, we are grateful to deliver my sincere obligation to Dr. P. BALAMURUGAN, Head of the Department, Mechatronics Engineering, who has been the backbone of our project, thereby extending continuous support anytime we required.

II. STATEMENT OF THE PROBLEM

A problem remains a problem until a solution is proffered. With the limitations encountered in the use of ropes, ladders, scaffold and mechanical scissors lifts in getting to elevated height such as the amount of load to be carried, conformability, time consumption, much energy expended etc. the idea of a hydraulically powered scissors lift which will overcome the above stated limitations is use.

III. SCOPE OF THE STUDY

(2)

67 IV. DESIGN CALCULATION

Total length of platform = 760mm. Total width of plat form = 600mm TOP PLATE DESIGN:

𝑀

𝐼 =

𝜎 𝑦

Where

M= Maximum bending moment = 𝑁𝑚𝑚2 I= Moment of inertia = 𝑚𝑚4

𝜎= Yield stress / FOS = N/m𝑚2 y= distance from neutral axis = mm b= breath of the plate = mm d= thickness of the plate = mm For mild steel yield stress = 248N/m𝑚2 𝜎 = Yield stress / FOS = 248

2 = 124 N/m𝑚 2

𝑀𝑚𝑎𝑥 =

𝑊𝐿2 8 = 2 ∗

7602

8 = 144400 Nmm According to golden ratio

𝑏

𝑑 = 1.618 b = 1.618d

I =𝑏𝑑

3

12 = 1.618𝑑

12 ∗ 𝑑

3

= 1.618𝑑64 12 I = 0.13𝑑4

𝑀

𝐼 =

𝜎 𝑦

144400

0.13𝑑4 =

124 𝑑 144400

0.13𝑑4 =

248 𝑑 144400

32.24 = 𝑑4

𝑑

𝑑3_{= 4478.90} d = 16.48 mm Reaction force,

𝑅𝐴 = 𝑅𝐵 = 𝑊𝐿

2 = 760 ∗2

2 = 760 N

BOTTOM PLATE DESIGN:

𝑀

𝐼 =

(3)

68

𝑀𝑚𝑎𝑥 =

𝑊𝐿2 8

= 4 ∗7602

8 = 288800 Nmm b = 1.618d

I = 0.13𝑑4

288800 0.13𝑑4 =

124 𝑑

2 288800

0.13𝑑4 = 𝑑

3

𝑑3 _{= 8957.81} D = 20.76 mm

Reaction force,

𝑅𝐴 = 𝑅𝐵 = 𝑁𝐿

2 = 4 ∗760

2 = 1520 N

LINKS:

Scissor links

D = 380 mm AB = 380 mm

∑𝑀𝑐 = 0 = w.d+𝑤1(

𝐴𝐵

2) − 𝐷𝑦∗ 𝐴𝐵 = 0

𝐷𝑦 = w.d+ 𝑤1(𝐴𝐵₂)

𝐴𝐵

= 380𝑤

380 +

𝑤1(380₂)

380

𝐷𝑦 = w+0.5𝑤1

∑𝐹𝑜𝑦 = 0

= 𝐷𝑦− 𝐶𝑦− 𝑤1− 𝑤 = 0

𝐶𝑦 = 𝐷𝑦− 𝑤1− 𝑤

𝐶𝑦 = 𝑤 + 0.5𝑤1− 𝑤1− 𝑤

𝐶𝑦 = -0.5𝑤1

∑𝐹𝑜𝑥 = 0

= 𝑃𝑥− 𝐹𝑥 = 0

𝑃𝑥 = 𝐹𝑥

𝐹𝑥 = Pcos𝛽

∑𝐹𝑜𝑦 = 0

= -𝐷𝑦+ 𝑃𝑦− 𝐹𝑦− 𝑤1

2 − 𝑐𝑦 = 0 = 𝐹𝑦 = 𝑃𝑦− 𝐷𝑦−

𝑤₁ 2 − 𝑐𝑦

𝐹𝑦 = 𝑃𝑦− 𝑤 − 0.5𝑤1− 𝑤1

2 + 0.5𝑤1

𝐹𝑦 = 𝑃𝑦− 𝑤 − 0.5𝑤1

𝐹𝑦 = 𝑃𝑠𝑖𝑛𝛽 − 𝑤 − 0.5𝑤1

Rotating around point c, ccw is positive direction ∑𝑀𝑐 = 0

= 𝑤1 2 .

𝐿

2cosα+𝐷𝑦𝐿𝑐𝑜𝑠𝛼 − 𝑃𝑠𝑖𝑛𝛽 ( 𝐿

2+ 𝛼) 𝑐𝑜𝑠𝛼 +

𝐹𝑦 𝐿

2cosα-Pcosβ( 𝐿

2+ 𝑎)𝑠𝑖𝑛𝛼 + 𝐹𝑥 𝐿

2𝑠𝑖𝑛𝛼 = 0 = 𝑤1

2 . 𝐿

2cosα+𝑊𝐿𝑐𝑜𝑠𝛼 + 0.5𝑤1𝐿𝑐𝑜𝑠𝛼 − 𝑃𝑠𝑖𝑛𝛽 ( 𝐿

2+ 𝛼) 𝑐𝑜𝑠𝛼 + 𝑃𝑠𝑖𝑛𝛽

𝐿

2𝑐𝑜𝑠𝛼 − 𝑊

𝐿

2𝐶𝑂𝑆𝛼 − 0.5𝑤1 𝐿 2𝑐𝑜𝑠𝛼 −

𝑃𝑐𝑜𝑠𝛽 (𝐿

2+ 𝑎) 𝑠𝑖𝑛𝛼 + 𝑃𝑐𝑜𝑠𝛽

𝐿

(4)

69 0.5𝑤1𝐿𝑐𝑜𝑠𝛼 + 0.5𝑊𝐿𝑐𝑜𝑠𝛼 − P ∗ a(sin𝛽cos𝛼 + 𝑐𝑜𝑠𝛽𝑠𝑖𝑛𝛼) = 0

0.5Lcosα(w+𝑤1)-P*a(sin𝛽cos𝛼 + 𝑐𝑜𝑠𝛽𝑠𝑖𝑛𝛼) = 0

P = 𝐿𝑐𝑜𝑠𝛼(

𝑤 2+𝑤12)

a∗sin(𝛼+𝛽) We know that,

L = length of the entire link = 755 mm

a = distance between center of link and cylinder pivot = 350 mm

w = weight acting on the elevator = 1500 N

𝑤1 = weight of the link and top plate(approx.) = 500 N

𝛼 = angle between cylinder and link axis = 45° 𝛽 = angle between cylinder axis and bottom plate = 0

P = 755cos45 (

1500 2 +

500 2 )

350[sin(45+0)] P = Force = 2157 N

𝐶𝑦 = 0.5𝑤1 = 0.5 ∗ 1500

= 750 N

𝐷𝑦 = w + 0.5𝑤1 = 1500 + 500 2 = 1750 N

𝐶𝑦𝑥 = cos45° ∗ 750 = 530 N

𝐶𝑦𝑦 = sin45° ∗ 750 = 530 N

𝐷𝑦𝑥 = cos45° ∗ 1750 = 1238 N

𝐷𝑦𝑦 = 1750 ∗ 𝑐𝑜𝑠45° = 1238 N

Sin45°= P𝑦

1

𝑃 P𝑦1_{= Psin45} = 2157 ∗ 𝑠𝑖𝑛45

= 1526 N

Cos45° = P𝑥

1

𝑃 P𝑥1_{= Pcos45} = 1526 N Sin45° = 𝑤1

2y/ 𝑤1

2 = 𝑤1

2y 𝑤1

2sin45°= 250 ∗ 𝑠𝑖𝑛45° = 177 N Cos45° = 𝑤1

2x/ 𝑤1

2x 𝑤₁

2 𝑥 = 𝑤₁

2cos45° = 250 ∗ 𝑐𝑜𝑠45

= 177 N

Force acting on the pin is determined by

(5)

70 F𝑥1₌_{−1238 + 1526 − 177 − 530}₌₋₁₉₄₅

𝐹1₌_√𝐹𝑥

12+ √𝐹𝑦12 = √(−1945)2+ √(−1945)2 = 2750 N Leg Two similar to leg One,

𝐵𝑦𝑥 = C𝑦𝑥 = cos45∗ 750

= 530 N B𝑦𝑦 = C𝑦𝑦 = sin45∗ 750 = 530 N

Sin45° = P𝑦11 𝑃 P𝑦11_{= Psin45} 2157sin45 = 1526 N

Cos45° = P𝑥

11

𝑃 P𝑥11_{= Pcos45}

= 2157cos45 = 1526 N PNEUMATIC CYLINDER:

Pressure = 𝐹𝑜𝑟𝑐𝑒 𝑎𝑟𝑒𝑎

Minimum pressure of hydraulic cylinder = 15 bar

1.5 = 2157 𝜋𝑟2

𝜋𝑟2 ₌2157 1.5

𝜋𝑟2_{= 1438 m}_𝑚2 r = √457.72

r = 21.39 mm d = 42.78 mm For standard 63mm is selected.

BOLT:

Bolt selection, Single shear = 𝐹𝑠

𝐴

𝐹𝑠 =

𝑌𝑖𝑒𝑙𝑑 𝑠𝑡𝑟𝑒𝑠𝑠 2

For mild steel yield stress = 248 N/m𝑚2

𝐹𝑠 =

248 2

= 124 N/m𝑚2

124 = 𝐹

𝜋(3)2

F = 3506.01 N

(6)

71 Automatic motion is obtained by pressing the push buttons that moves the elevator to the desired position placed. The elevator stops at the position that is being sensed by the limit switches placed at bottom plates.

By receiving the control the signals are being sent to the Direction Control Valve (DCV) with is solenoid controlled and moves the piston which tends the elevator to move to the up and down motions.

V. PICMICROCONTROLLER

The PIC16F877A is one of the latest products from Microchip. It features all the components which modern microcontrollers normally have. For its low price, wide range of application, high quality and easy availability, it is an ideal solution in applications such as: the control of different processes in industry, machine control devices, measurement of different values etc.

VI. LIMIT SWITCHES

A limit switch is an electromechanical device that consists of an actuator mechanically linked to a set of contacts. When an object comes into contact with the actuator, the device operates the contacts to make or break an electrical connection. Limit switches are used in a variety of applications and environments because of their ruggedness, ease of installation, and reliability of operation. They can determine the presence or absence, passing, positioning, and end of travel of an object. They were first used to define the limit of travel of an object; hence the name "Limit Switch".

Standardized limit switches are industrial control components manufactured with a variety of operator types, including lever, roller plunger, and whisker type. Limit switches may be directly mechanically operated by the motion of the operating lever. A reed switch may be used to indicate proximity of a magnet mounted on some moving part. Proximity switches operate by the disturbance of an electromagnetic field, by capacitance, or by sensing a magnetic field.

VII. 5/3SOLENOID OPERATED DIRECTION CONTROL VALVE

They are widely used in the hydraulics industry. These valves make use of electromechanical solenoids for sliding of the spool. Because simple application of electrical power provides control, these valves are used extensively.

However, electrical solenoids cannot generate large forces unless supplied with large amounts of electrical power. Heat generation poses a threat to extended use of these valves when energized over time. Many have a limited duty cycle. This makes their direct acting use commonly limited to low actuating forces.

(7)

72 A bi-stable pneumatic valve is typically a pilot valve that is a 3 ported 2 position valve. The valve retains its position during loss of power, hence the bi-stable name.

Bi-stability can be accomplished with a mechanical detent and 2 opposing solenoids or a "magna-latch" magnetic latch with a polarity sensitive coil. Positive opens and negative closes or vice versa. The coil is held in position magnetically when actuated.

VIII. PUSH BUTTON

A push-button (also spelled pushbutton) or simply button is a simple switch mechanism for controlling some aspect of a machine or a process. Buttons are typically made out of hard material, usually plastic or metal. The surface is usually flat or shaped to accommodate the human finger or hand, so as to be easily depressed or pushed. Buttons are most often biased switches, though even many un-biased buttons (due to their physical nature) require a spring to return to their un-pushed state.

LOAD CELLS

The heart of any weighing system is the load cell. Load cells are designed to sense force or weight under a wide range of adverse conditions; they are not only the most essential part of an electronic weighing system, but also the most vulnerable. In order to get the most benefit from the load cell, the user must have a thorough understanding of the technology, construction and operation of this unique device. In addition, it is imperative that the user selects the correct load cell for the application and provide the necessary care for the load cell during its lifetime. Understanding these important issues and properly maintaining the load cells will ensure trouble free weighing for a long period of time.

IX. LOAD CELL SELECTION

Load cell selection in the context of trouble free operation concerns itself primarily with the right capacity, accuracy class and environmental protection, rather then with a particular measuring principle like bending, shear, compression or ring torsion. While saying this, it should also be recognized that a particular measuring principle might offer distinct advantages in terms of overload capabilities or the ease of mounting.

In General careful consideration must be given to any reason for failure. If this has occurred as a result of ingress of water or chemicals, then continued deterioration of any other load cell(s) in the system can be expected, resulting in mechanical failure. This failure can have serious safety and cost consequences. Always remove the load cell with care and attach a label with comments to the problem or mode of failure. Never cut the cable at the gland to facilitate removal; load cells cannot be tested by us without cables.

X. CONCLUSION

The design of a portable work platform elevated by a hydraulic cylinder was carried out meeting the required design standards. The portable work platform is operated by hydraulic cylinder which is operated by a hydraulic power pack. The scissor lift can be design for high load also if a suitable high capacity hydraulic cylinder is used. The hydraulic scissor lift is simple in use and does not required routine maintenance. It can also lift heavier loads. The main constraint of this device is its high initial cost, but has a low operating cost. The shearing tool should be heat treated to have high strength. Savings resulting from the use of this device will make it pay for itself with in short period of time and it can be a great companion in any engineering industry dealing with rusted and unused metals.

XI. FUTURE AND SCOPE

This device affords plenty of scope for modifications for further improvements and operational efficiency, which should make it commercially available and attractive. Hence, its wide application in industries, hydraulic pressure system, for lifting of vehicle in garages, maintenance of huge machines, and for staking purpose. Thus, it is recommended for the engineering industry and for commercial production.

REFERENCES

[1] Ferdinand P.Beer & E.Russell Johnston, “Vector Mechanics for Engineers Statics”, 10th Editon, 2015 by TATA McGraw Hill Publication.

[2] Robert L.Norton, “Design of Machinery”, 2005, Editon by TATA McGraw Hill Publication. [3] “DesignData”, Book for Engineers PSG College of Technology by Kalaikathir Publication, 2013.

[4] Henry W.Saslach JR. and Rowl and W.Armstrong 2005 .“Deformatable Bodies and their Material Behaviour”, John

Wiley and sons inc.

[5] Okolieizunnajude, “Design and construction of hydraulic scissors lift”, 2011.

[6] Jaydeepm. bhatt, milanj. Pandya, “Design and analysis of anaerial scissor lift”, 2012.

(8)

73

[8] Enoch L. Newlin, “Scissor lift mechanism employing telescopable electro-mechanical based lift actuation arrangement”, 2000

[9] Mahmood Ronaghi, John Z. Wu, Christopher S.Pan, James R.Harris, Daniel Welcome, SharonS. Chiou, Brad Boehlerand Ren G.Dong, “Aninitiative to model staticstability”,2009.

[10] Ren G.Dong, Christopher S.Pan, Jared J.Hartsell, Daniel E.Welcome, Tim Lutz, Anne Brumfield, James R.Harris, JohnZ.Wu, Bryan Wimer, Victor Mucino, Kenneth, “An investigation on the dynamics tability of scissorlift”, 2012.