MINOR PROJECT REPORTMotorized Scissor LiftSUBMITTED IN PARTIAL FULLFILLMENTFOR THE AWARD OF DEGREE OFBACHELOR OF TECHNOLOGYMECHANICAL ENGINEERING

Under the guidance of: Submitted By: Name: Mr.Piyush Rana Vikas singh(me12/12451)Designation: PROFESSOR Vikas sharma(me/12/12450)Department: ME Sanjay dangi(Me/12/12434) Surinder singh(Me/12/12446) Tanveer saini(Me/12/12447)

[SCHOOL OF ENGINEERING AND TECHNOLOGY-BHADDALPost Office:Mianpur,District:Ropar,Punjab-140001

CERTIFICATE OF PROJECTThis is to certify that Vikas Singh (1234236) , Vikas Sharma (1245235), Tanveer (1245232) , Surinder Singh (1245231) , Sanjay Dangi (1245219) who are the student of bachelor of technology of mechanical engineering department of institute of engineering and technology Bhaddal, Rupnagar affiliated to Punjab technical university, Jalandhar has completed the minor project on Motorized Scissor Lift under the guidance of Mr. Piyush Rana.His Overall performance during the project period was ______________.

Signature:-DATE:- Name:-Designation:-Department:-

AbstractThis paper presents analytical and experimental results of a motorized scissor lift and their suitability for a particular class of complex mechanisms: Robotic lift. In practice, robotic lift usually comprise of multiple segments connected by joints. Some robotic lift provided legged, wheeled or tracked propulsion, and in addition, Scissor type lift to lift loads. It was applied to investigate the effect of scissor structure flexibility on the tip-over potential of the lift, to understand tip-over mechanisms. Scissor lifting mechanism is the first choice for automobiles and industries for elevation work. The system has a one degree of freedom. There are several procedures for deriving dynamic equations of rigid bodies in classical mechanics. The simulation gives a clear idea about motor torque sizing for different link lengths of the mechanism over a linear displacement.

ACKNOWLEDGEMENTI have taken efforts in this project. However, it would not have been possible without the kind support and help of many individuals and organizations. I would like to extend my sincere thanks to all of them.

I am highly indebted to Mr. Piyush Rana for their guidance and constant supervision as well as for providing necessary information regarding the project and also for their support in completing the project.I would like express my gratitude towards my parents, faculty and members of department of mechanical engineering of IET BHADDAL for their kind cooperation and encouragement which help me in completion of this project. I would like to express my special gratitude and thanks to workshop instructors for giving me such attention and time.My thanks and appreciations also go to my fellows in developing the project and people willingly helped me out with their abilities.

Contents GENERAL SAFRTY STATEMENTS MECHATRONICS OBJECTIVE DESCRIPTION BLOCK DIAGRAM AIM/OBJECTIVE OF SCISSOR LIFT LIMITING DEFLECTION IN SCISSOR LIFT INPUT SPECIFICATIONS SWITCH, FUNCTION AND FEATURES CONCLUSIONS AND RECOMMANDATIONS

MotorizedScissorLift

GENERAL SAFETY STATEMENTS To ensure this quality product is safely and correctly utilized, all instructions within this manual must be read and understood prior to equipment start-up. Be aware of all safety labels on machinery. If you do not understand any of the safety instructions or feel there may be safety labels missing, contact your supervisor or product supplier immediately! Para garantizar que este producto de calidad se utilice correctamente y con seguridad, es necesario leer y comprender las instrucciones incluidas en este manual, antes de comenzar a utilizar el equipo. Est atento a todas las etiquetas de seguridad que se encuentran en las mquinas. Si no entiende alguna de las instrucciones de seguridad o considera que faltan algunas etiquetas de seguridad, comunquese inmediatamente con su supervisor o proveedor del product!COMPLIANCE WITH SAFETY STANDARDS Compliance with safety standards, including federal, state and local codes or regulations is the responsibility of the equipment purchaser(s). Placement of guards, safety labels and other safety equipment is dependent upon the area and use to which the system is applied. A safety study should be made of the equipment application by the purchaser(s). It is the purchasers responsibility to provide any additional guards, safety labels or other safety equipment deemed necessary based on this safety study. The information contained in this safety manual is correct at the time of printing. Due to the continuing development of product lines, changes in specifications are inevitable. The company reserves the right to implement such changes without prior notice.If you suspect fire hazards, safety hazards, dangers towards health or any other job safety concerns, consult your federal, state or local codes.Certain safety information in this document was reprinted from ASME B20.1-2000 by permission of The American Society of Mechanical Engineers. All rights reserved. Inspect equipment for safety labels. Make sure personnel are aware of and follow safety instructions.

Maintain an orderly environment in the vicinity of the equipment at all times. Clean up spilled materials or lubricants immediately. All personnel shall be instructed regarding the necessity for continuous care and attention to safety during the operation of the equipment. They must be trained to identify and immediately report all unsafe conditions or practices relating to the equipment and its operation.Know your companys machine specific Lockout / Tagout procedure. Do Not perform maintenance until electrical disconnect has been turned off! Replace all safety devices, guards and guarding prior to equipment start-up.

SAFETY INFORMATION: GENERAL SAFETY LABELSSafety labels have been placed at various points on the equipment to alert everyone of potential dangers. Inspect equipment for proper position of safety labels and make sure all personnel are aware of the labels and obey their warnings. As mentioned in the previous section, a safety study should be made of the equipment application by the purchaser(s). It is the purchasers responsibility to provide any additional guards, safety labels or other safety equipment deemed necessary based on this safety study. The following pages contain typical safety labels that may have been attached to your equipment.

SAFETY INFORMATION: SCISSOR LIFT SAFETY LABELS

SAFETY INFORMATION: INSTALLATIONSAFETY LOADING / UNLOADING Have trained personnel load or unload equipment. The equipment must be properly handled when transferring from the unloading area to final site location to prevent damage.

GUARDS / GUARDING Interfacing of Equipment. When two or more pieces of equipment are interfaced, special attention shall be given to the interfaced area to ensure the presence of adequate guarding and safety devices.

Guarding Exceptions. Wherever conditions prevail that would require guarding under this standard but such guarding would render the equipment unusable, seek guidance from your safety professional.

ANCHORING DO NOToperate equipment unless it is properly anchored. Serious injury or death may result.

SAFETY WARNING Install all safety devices, guards and guarding prior to equipment start-up.

MECHATRONICSMechatronicsis a design process that includes a combination ofmechanical engineering,electrical engineering,control engineeringandcomputer engineering. Mechatronics is amultidisciplinaryfield of engineering, that is to say, it rejects splittingengineeringinto separate disciplines. Originally, mechatronics just included the combination of mechanics and electronics, hence the word is a combination ofmechanics and electronics; however, as technical systems have become more and more complex the word has been "updated" during recent years to include more technical areas.French standard NF E 01-010 gives the following definition: approach aiming at the synergistic integration of mechanics, electronics, control theory, and computer science within product design and manufacturing, in order to improve and/or optimize its functionality".Many people treat "mechatronics" as a modern buzzword synonymous with "electromechanical engineering".However, other people draw a distinction between an "electromechanical component" -- does not include a computer; anelectro-mechanical computer(such as theZ4) -- does not include an electronic computer; vs. a "mechatronic system" -- a computer-controlled mechanical system, including both an electronic computer and electromechanical components.Mechatronics is the synergistic integration of Mechanical Engineering with Electronics and intelligent computer control in the design and manufacture of products and processes & it has futuristic application in the cutting edge technology.Mechatronics system engineering has gained global interest in the past decade from the educational and industrial sectors.This unique inter disciplinary programme is launched for the first time in India at MIT campus in the year 1998.Candidates with a Bachelor's Degree in Electrical and Electronics Engineering,Mechanical Engineering, Electronics and Communication Engineering, Computer Science and Engineering, Electronics & Instrumentation Engineering are eligible for this highly specialized four semester M.E. Programme.Mechatronics is essential in the design of intelligent products; it allows engineers to transform their concepts into reality. Within the next few decades, the trade of intelligent products with improved flexibility, performance, reliability and maintenance will be crucial for the economic vitality of any country.Mechatronics has wide range of applications especially in robotics, industrial & home automation, home appliances, inline assembly of automobiles, engine management system, aerospace, nuclear & marine Engineering.

ObjectiveA jack is mechanical device used to lift heavy loads or apply great forces. A mechanical jack is a device which lifts heavy equipment. Scissor lift usually use mechanical advantage to allow a human to lift a small weight by manual force alone. More powerful lift use hydraulic power to provide more lift over greater distance. The mechanical advantage is the factor by which a mechanism multiplies the force or torque applied to it. An automotive lift is a device used to raise all or part of a vehicle or any materials into the air in order to facilitate repairs or to ease. Most people are familiar with the basic auto lift that was still included as standard equipment . These days, fewer people than ever have had to use a scissor lift. This is due to the continuing improvements in modern tires that have made getting a flat rare. Even so, people who like to lift small weights or want to lift books in liberary to get ease in work can use scissor lift.

Nowadays in this country,By increasing its load capacity it can be used as scissor jack aslo, most of the cars were equipped with the scissor car jack. We found that the scissor car jack were very difficult to be used especially by women because this types of jack needed more strength and energy to operate this jack by turning the lead screw. Thus, we want to develop a product based from the problem faced by the users who drive a car regarding to this issue. To overcome this problem, a research has been conducted to find the solution on how to design a car jack for the car using the simplest and cheapest way while it is energy saving. Although there were many ways to solve this problem, we recommend that the design this car jack system is the practical way when we considered all the factors and consequences especially about the analysis to develop this product.s. The normal car jack we have in the market is operated using bare hands and it is time consuming. It also requires much energy from the person to rotate the jack. Hence, this project had been prepared to recommend the design of the car jack that is user friendly and easier to operate as do not required too much money to develop this product.

DescriptionThis project is about the designing and fabricating the Scissor lift. This can be operating using electricity to lift the load. In case of hydraulic and pneumatic jack a force is applied by the human to lift the small load or car which uses large human efforts and time wasting. So to overcome this limitation an electric lift is used. The main components used in this project are motor jack, connecting wires and switch. In this project the motor is used to lift the jack which is powered through electric source. The direction of jack is controlled through switch.

JackA mechanical jack is a device which lifts heavy equipment. The most common form is a car jack, floor jack or garage jack which lifts vehicles so that maintenance can be performed. Car jacks usually use mechanical advantage to allow a human to lift a vehicle. More powerful jacks use hydraulic power to provide more lift over greater distances. Mechanical jacks are usually rated for a maximum lifting capacity (for example, 1.5 tons or 3 tons).

Design To design is either to formulate a plan for the satisfaction of a specified need or to solve a problem. If the plan results in the creation of something having a physical reality, then the product must be functional, safe, reliable, competitive, usable, manufacturable, and marketable. .These terms are defined as follows:I.Functional: The product must perform to fill its intended need and customer expectation.II.Safe: The product is not hazardous to the user, bystanders, or surrounding property. Hazards that cannot be designed out are eliminated by guarding (a protective enclosure); if that is not possible, appropriate directions or warning are provided.III.Reliable: Reliability is the conditional probability, at a given confidence level, that the product will perform its intended function satisfactorily or without failure at a given age.IV.Competitive: The product is a contender in its market.V.Usable: The product is user friendly accommodating to human size, strength. Posture, reach, force, power and control.VI.Manufacturable: The product has been reduced to a minimum number of parts. Suited to mass production, with dimensions, distortion, and strength under control.VII.Marketable: The product can be bought, and service (repair) is availableIt is important that the designer begin by identifying exactly how to recognize a satisfactory alternative, and how to distinguish between two satisfactory alternatives in order to identify the better. From this, optimization strategies can be formed or selected. Then the following tasks unfold:Invent alternative solutionEstablish key performance metricsThrough analysis and test, simulate and predict the performance of each alternative, retain satisfactory alternatives, and discard unsatisfactory ones.Choose the best satisfactory alternatives discovered as an approximation to optimality.Implement the designThe characterization of a design task as a design problem can introduce the idea that, as a problem, it has solution

Block Diagram

Jack

Mechatronics

Power SupplyWiperMotorSwitch 2

Switch 1

SCISSOR LIFT

A scissor lift is a device used for lifting purposes, its objectives is to make the table adjustable to desirable height.A scissor lift provide the most economic dependable and versatile methods of lifting loads, it has few moving parts, which may only require lubrication. This lift table raises the load smoothly to any desired height. The scissor lift can be used in combination with any of the previously mentioned application, i.e. hydraulic, pneumatic or electrical. In order to reduce the inadequacies of the devices mentioned above, a scissors mechanism is proposed. This mechanism is incorporated with a power screw and the top of the scissors is attached a table platform. This device will make use of the power generated from a power screw to raise or lower a platform manually.AIMS/OBJECTIVES

The aim of this study is to design a scissors lifting device that can be used in the

automobile sector. The design conditions are to meet the following specifications;

a) The device is limited to an average load of 10 kg

b) The device will have a maximum lift of 70 cm

c) This objective is desirable to be achieved through the rotation of the screw to raise or lower the scissor platform.

d) The system must be operated on a flat surface.

Regulated Power Supply

Power supplies are designed to convert high voltage AC mains to a suitable low voltage supply for electronic circuits and other devices. A power supply can be broken down into a series of blocks, each of which performs a particular function.

For example a 5V regulated supply:

Each of the blocks has its own function as described below

1. Transformer steps down high voltage AC mains to low voltage AC.

2. Rectifier converts AC to DC, but the DC output is varying.

3. Smoothing smoothes the DC from varying greatly to a small ripple.

4. Regulator eliminates ripple by setting DC output to a fixed voltage.

Each of the blocks has its own function as described below:

1. Transformer steps down high voltage AC mains to low voltage AC. The step down transformer of 12-0-12, 750mA will be used in our project.

1. Rectifier converts AC to DC, but the DC output is varying. The ripple factor of Bridge rectifier is than the other rectifier circuits. So here in our project we will use bridge rectifier to convert the AC into DC.

1. Smoothing smoothes the DC from varying greatly to a small ripple. A electrolytic capacitor of 1000uF/50V will be used as a filter/smoothing circuit to get pure DC.

1. Regulator eliminates ripple by setting DC output to a fixed voltage. There are two types of regulator series. First is positive voltage regulator series (78XX) and second is negative voltage regulator series (79XX). In our project we need positive voltage (+5V) so we will use 7805 to regulate the voltage.

Transformer

Transformers convert AC electricity from one voltage to another with little loss of power. Transformers work only with AC and this is one of the reasons why mains electricity is AC. The two types of transformers

Step-up transformers increase voltage,

Step-down transformers reduce voltage.

Mostpowersuppliesuse astep-downtransformer to reduce the

dangerously high mainsvoltage (230V in UK)to a safer low voltage. The

input coil is called theprimary and the output coil is called the secondary.

Thereis noelectricalconnectionbetween the two coils, instead they are

linked by analternatingmagneticfield createdin the soft-iron core of the

transformer. The two lines in the middle of the circuit symbol represent the core. Transformers waste very little power so the power out is (almost) equal to the power in. Note that as voltage is stepped down current is stepped up. The ratio of the number of turns on each coil, called the turn ratio, determines the ratio of the

voltages. A step-down transformer hasa large number of turns on its primary

(input) coil which is connected to thehigh voltage mains supply, and a small

number of turnsonits secondary (output) coil to give a low output voltage.

Turns Ratio ==

AndPower Out = Power In

Vs Is=Vp Ip

Where

Vp = primary (input) voltage

Np = number of turns on primary coil

Ip = primary (input) current

Ns = number of turns on secondary coil

Is = secondary (output) current

Vs = secondary (output) voltage

Bridge Rectifier

A bridge rectifier can be made using four individual diodes, but it is also available in special packages containing the four diodes required. It is called a full-wave rectifier because it uses all AC wave (both positive and negative sections). 1.4V is used up in the bridge rectifier because each diode uses 0.7V when conducting and there are always two diodes conducting, as shown in the diagram below. Bridge rectifiers are rated by the maximum current they can pass and the maximum reverse voltage they can withstand (this must be at least three times the supply RMS voltage so the rectifier can withstand the peak voltages). In this alternate pairs of diodes conduct, changing over the connections so the alternating directions of AC are converted to the one direction of DC.

OUTPUT Full-wave Varying DC

SMOOTHING

Smoothing is performed by a large value electrolytic capacitor connected across the DC supply to act as a reservoir, supplying current to the output when the

varying DC voltage from the rectifier is falling. The diagram shows the unsmoothed varying DC (dotted line) and the smoothed DC (solid line). The capacitor charges quickly near the peak of the varying DC, and then discharges as it supplies current to the output.

Note that smoothing significantly increases the average DC voltage to almost the peak value (1.4 RMS value). For example 6V RMS AC is rectified to full wave DC of about 4.6V RMS (1.4V is lost in the bridge rectifier), with smoothing this increases to almost the peak value giving 1.4 4.6 = 6.4V smooth DC.

Smoothing is not perfect due to the capacitor voltage falling a little as it discharges, giving a small ripple voltage. For many circuits a ripple which is 10% of the supply voltage is satisfactory and the equation below gives the required value for the smoothing capacitor. A larger capacitor will give fewer ripples. The capacitor value must be doubled when smoothing half-wave DC.

Smoothing capacitor for 10% ripple, C = 5 Io

Vs f

Where

C = smoothing capacitance in farads (F)

Io = output current from the supply in amps (A)

Vs = supply voltage in volts (V), this is the peak value of the unsmoothed DC F = frequency of the AC supply in hertz (Hz), 50Hz in the UK

REGULATOR

Voltage regulator ICs are available with fixed (typically 5, 12 and 15V) or variable output voltages. They are also rated by the maximum current they can pass. Negative voltage regulators are available, mainly for use in dual supplies. Most regulators include some automatic protection from excessive current (overload protection') and overheating (thermal protection'). Many of the fixed voltage regulator ICs has 3 leads and look like power transistors, such as the 7805 +5V 1A regulator shown on the right. They include a hole for attaching a heat sink if necessary.

Working of Power Supply

Transformer

The low voltage AC output is suitable for lamps, heaters and special AC motors. It is not suitable for electronic circuits unless they include a rectifier and a smoothing capacitor.

Transformer + Rectifier

The varying DC output is suitable for lamps, heaters and standard motors. It is not suitable for electronic circuits unless they include a smoothing capacitor.

Transformer + Rectifier + Smoothing

The smooth DC output has a small ripple. It is suitable for most electronic circuits.

Transformer + Rectifier + Smoothing + Regulator

D11N4007

J1D21000uf

3

2gndC1

1D3V

D4

LM7805

12+5V

VIN VOUT

GND

3

The regulated DC output is very smooth with no ripple. It is suitable for all electronic circuits.

Regulated Power Supply Layout

LIMITING DEFLECTION IN SCISSOR LIFT

Selecting a lift with design capacity greater than required for the application; most scissor lift design for duty at higher capacities will experience less stress in all structural components as well as lower system pressures, at lower, working capacities. Reduced stresses and pressure always result in reduced deflection.

Avoid transfer of load within the first 20% of lift travel: To minimize stress and deflection, at transfer elevations, it is critical to design the conveyor or transfer systemto ensure that these elevations are above the scissor lifts critical zone of the first 20% of the lift available travel.

Transfer load over fixed end of the lift platform: First if possible, load should not be transfer over the sides of a raised scissor lift is much more difficult to control deflection when the load is not shared equally between the two scissor legs pairs. Load transfer should be made over the hinge or fixed end of the lift platform to avoid placing concentrated load on the less supported, over hung end of the platform, provided the platform is equipped with trapped roller or is otherwise capable of withstanding this edge loading without risk of platform tipping up or losing contact with the rollers.

Ensure that the based frame is lagged down and fully supported:

First, base frame should be adequately attached to the surface on which they are mounted. Base frame that are not bolted, welded or otherwise attached to withstand the upward force created by the eccentric loading of the platform will contribute to deflection by bending or moving while resisting such forces. Bases must also be rigidly supported beneath the entire perimeter of the frame in order to withstand without deflection on the four point loads imposed upon the frame from above by the four scissor-legs. Two moving roller and two fixed hinge points.

SUMMARY OFDEFLECTION

Although, there are few literatures on the design of scissors lift, this chapter has highlighted the features and constraints in the design and fabrication of a prototypeunit. ANSI MH29.1 accurately points out that it is the responsibility of the user/purchaser to advise the manufacturer where deflection may be critical to the application. It has been noted that there are industrial best practices which can be applied to reduce the impact or amount of deflection being experience.

INPUT SPECIFICATIONS

Research carried out in the automobile industry reveals that one of the heaviest components of the automobile car is the car engine which is of average weight of 272 kg. By this factor, our control weight would be 280 kg for safer design of the scissor lift table platform for assembly purposes in the auto industry.Switch A switch is used in order to start or stop the entire operation of the screw jack. The type of switch that is used is known as a toggle switch. A toggle switch is a class of electrical switches that are manually actuated by a mechanical lever, handle, or rocking mechanism. Toggle switches are available in many different styles and sizes, and are used in countless applications. Many are designed to provide, e.g., the simultaneous actuation of multiple sets of electrical contacts, or the control of large amounts of electric current or mains voltages. The word "toggle" is a reference to a kind of mechanism or joint consisting of two arms, which are almost in line with each other, connected with an elbow-like pivot. However, the phrase "toggle switch" is applied to a switch with a short handle and a positive snap-action, whether it actually contains a toggle mechanism or not. Similarly, a switch where a definitive click is heard, is called a "positive on-off switch".Function The basic function of a screw jack is to lift a portion of a vehicle. Typically this is used to change a tire although other maintenance is sometimes performed.Features All jacks have safety features to protect the user from accidental injury. Wide bases help to stabilize a jack and prevent tilting or sinking into soft soil. Most car jacks also come equipped with their own handle or cranking mechanism, but alternately many of these also will accept the flat end of a tire tool to jack up a vehicle. When in the extended position, jacks will have a stop point that prevents the user from overextending the jack beyond its rated capabilities. When in the contracted position, jacks that are provided by the manufacturer will have a storage area specially formed or designed for the jack to rest in when not in use.

APPLICATIONS OF SCISSOR LIFT

Shopping malls (Big Bazar, Vishal Megamart, etc) Library Paper Printing Wood working

CONCLUSIONS AND RECOMMENDATION

CONCLUSIONS

The design of a portable work platform elevated by the turning effect of a horizontal screw spindle was carried out successfully meeting the required design standards. The portable work platform is operated by turning a handle attached to the horizontal spindle. The scissor lift is only for average load, because the higher the load the higher the effort required. The screw operated scissor lift is simple in use and does not require much maintenance. For the present dimension we get a lift of 70cm, the scissor lift can lift a load of 10kg. 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. The device affords plenty of scope for modifications for further improvements and operational efficiency, which should make it commercially available and attractive. Hence, it should have a wide application in engineering industries and not just automotive industry alone. Thus, it is recommended for the engineering industry and for commercial production.RECOMMENDATIONS

It is recommended that the screw and thread should be lubricated frequently so as to reduce the amount of effort required to operate the system. This also reduces the amount of wear between the screw and the nut. It is also suggested that the spindle and nut should not be exposed to moisture so that it would not be susceptible to corrosion thereby reducing.