4/24/2015

BOX TRANSPORT MECHANISM

AWADHESH SINGH YADAV IDEAL INSTITUTE OF ENGINEERING & TECHNOLOGY

BOX TRANSPORT MECHANISM

A Project Report submitted In Partial Fulfillment of the Requirements

for the Degree of

BACHELOR OF TECHNOLOGY

in Mechanical Engineering

by

Awadhesh Singh Yadav (Roll No.- 1102840031) Danveer Saini (Roll No.- 1102840036) Gaurav Sagar (Roll No.- 1102840040) Mayank Kumar Jain (Roll No.- 1102840052) Nitesh Kumar Tripathi (Roll No.- 1102840059)

Under the Supervision of

Mr. Dharmendra Singh

(Professor/ Assistant Professor) Department of Mechanical Engineering

Ideal Institute of Engineering & Technology, Ghaziabad, Uttar Pradesh.

to the

UTTAR PRADESH TECHNICAL UNIVERSITY LUCKNOW (U.P.)

April 2015

i

CERTIFICATE

Certified that Awadhesh Singh Yadav (Roll No. 1102840031), Danveer Saini (Roll No.

1102840036), Gaurav Sagar (Roll No. 1102840040), Mayank Kumar Jain (Roll No.

1102840052) and Nitesh Kumar Tripathi (Roll No. 1102840059) has carried out the project work

presented in this report entitled for the award of Bachelor of

Technology from Uttar Pradesh Technical University, Lucknow, (U.P.) under my supervision.

The report embodies results of original work, and studies are carried out by the students

themselves and the contents of the report do not form the basis for the award of any other degree

to the candidate or to anybody else from this or any other University/Institution.

Signature:

Date:

Mr. Dharmendra Singh

(Professor /Assistant Professor)

Mechanical Engineering Department,

Ideal Institute of Technology, Ghaziabad

ii

ABSTRACT

This project aims for the utilization of kinematic synthesis (type, dimensional and

number) to fabricate a working physical model of an eight link transport mechanism. The

mechanism to be developed in its simplest form would perform the function of transporting

boxes/articles which are being fed onto two rails and are moved ahead one by one. The eight bar

mechanism allows moving more than one article as compared to its four bar counterpart.

Transport mechanisms generally move material and their application lies in various industries-

manufacturing, assembly, packaging etc.

In this project we apply the path generation synthesis and coupler curve synthesis and

study to fabricate our model which is an eight link transporter mechanism. The synthesis would

Chebyschev theorem for cognate linkages and parallel motion

generation where we want the output link of the mechanism to follow a particular path without

any rotation of the link as it moves along the path. The final model will be constructed by

modelling in CAD software solid edge that will eliminate the errors that might have crept in

graphical synthesis. In actual fabrication process the model will be refined as the final fitments

are done by tools and processes like welding, drilling, fitting, grinding. The model then

undergoes trial run and is examined for the prescribed motion characteristics.

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ACKNOWLEDGEMENT

We would like to express my gratitude to all those who gave me the opportunity to

complete this work. We would like to thank, Mr. Dharmendra Singh Assistant Professor (ME),

for giving guidance, stimulating suggestions and moral support. We are grateful to him for

sharing his time and expertise. His faith in us has always made more confident. It had been our

privilege to work under his guidance.

We would also like to thank Mr. Apurv Yadav Assistant Professor, Mechanical

Engineering Department for moral support, interest and valuable hints.

We are also thankful to all the faculty members of mechanical engineering department

and our colleagues for their cooperation.

We would like to thank our family for their continued support throughout this work. Our

parents have always been there for us and provided the best opportunities. No one has been as

motivating and inspirational to us as our parents. Thank you for your consistent help and support.

Awadhesh Singh Yadav (Roll No. 1102840031)

Nitesh Kumar Tripathi (Roll No.1102840059)

Mayank Kumar Jain (Roll No. 1102840052)

Gaurav Sagar (Roll No. 1102840040)

)

Danveer Saini (Roll No. 1102840036)

iv

TABLE OF CONTENTS DESCRIPTIONS PAGE NO.

CERTIFICATE .................................................................................................... i

ABSTRACT ........................................................................................................ ii

ACKNOWLEDGEMENT .......................................................................................................... iii

TABLE OF CONTENTS ...................................................................................... iv

LIST OF FIGURES ..................................................................................................................... vi

CHAPTER 1 ................................................................................................................................ 1

1.1 INTRODUCTION ............................................................................................................. 2

1.2 AIM ..................................................................................................................................... 4

1.3 OBJECTIVE ...................................................................................................................... 4

CHAPTER 2 ................................................................................................................................ 5

2.1 LINKAGE MECHANISM .............................................................................................. 6

2.2 SIMPLE PLANAR LINKAGES .................................................................................... 7

2.3 CRANK-ROCKER MECHANISM ............................................................................... 9

2.4 FUNCTIONS OF LINKAGES ..................................................................................... 10

2.5 FOUR LINK MECHANISMS ...................................................................................... 11

2.6 CLASSIFICATION ........................................................................................................ 15

2.7 TRANSMISSION ANGLE ........................................................................................... 17

2.8 ANALYSIS ...................................................................................................................... 18

CHAPTER 3 .............................................................................................................................. 21

3.1 MATERIAL AND DIMENSIONS .............................................................................. 22

3.2 TOOLS .............................................................................................................................. 26

3.3 PROCEDURE .................................................................................................................. 29

v

CHAPTER 4 .............................................................................................................................. 31

4.1 LOGIC .............................................................................................................................. 32

4.2 FUTURE WORK ............................................................................................................ 32

CHAPTER 5 .............................................................................................................................. 36

CONCLUSION ..................................................................................................................... 37

REFRENCES ....................................................................................................................... 38

APPENDIX ........................................................................................................................... 39

vi

LIST OF FIGURES

Figure 1 Box transport mechanism ................................................................................................. 3

Figure 2 Functions of four basic planar linkage mechanisms ......................................................... 7

Figure 3 Crank rocker mechanism .................................................................................................. 9

Figure 4 Four bar linkage .............................................................................................................. 11

Figure 5 Crank rocker ................................................................................................................... 13

Figure 6 Walking Beam ................................................................................................................ 14

Figure 7 Transmission angle ......................................................................................................... 17

Figure 8 Mechanism ..................................................................................................................... 18

Figure 9 Base structure ................................................................................................................. 22

Figure 10 Transporting link & Connecting rod ............................................................................ 23

Figure 11 Couplers ........................................................................................................................ 24

Figure 12 Crank and Rocker ......................................................................................................... 25

1

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CHAPTER 1

1.1 INTRODUCTION

There has been a serious demand for intermittent movement of packages in the industries

right from the start. Though the continuous movement is more or less important in the same field

the sporadic motion has become essential .The objective of our project is to produce a

mechanism that delivers this stop and move motion using mechanical linkages. The advantage of

our system over the conveyor system is that the system has a time delay between moving

packages and this delay can be used to introduce any alterations in the package or move the

package for any other purpose and likewise. While in conveyor system such actions cannot be

performed unless programmed module is used to produce intermittent stopping of the belt which

basically is costly. The prototype design requires electric motor, shafts and the frame of which

the frame and platform on which the packages are moved is fabricated. All the links are being

made of Wood which reduces the weight of the whole system including the head which has a

direct contact with the boxes being moved. The system is expected to move as heavy packages as

2 - 3kgs approximately.

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Figure 1 Box transport mechanism

The walking beam (in blue) pushes articles (in red) forward, and the material is left

stationary in the return stroke of the walking beam until the next cycle. The mechanism is for

moving articles with intermittent advancement. The eight-bar mechanism allows moving more

than one article, as compared to a four bar walking beam.

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1.2 AIM

The aim of this project is to fabricate the box moving mechanism, which can make easier

to move boxes from one section to the other while processing in the factories.

In a workstation, an assembly line in order to obtain the required production rate and to

achieve a minimum amount of idle time.

1.3 OBJECTIVE

Fabricate a Box transport mechanism which can move things from one place to another

Understand project planning and execution.

Understand the fabrication techniques in a mechanical workshop.

Understand the usage of various mechanical machine tools and also measuring tools.

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CHAPTER 2

2.1 LINKAGE MECHANISM

A linkage is a mechanism formed by connecting two or more levers together. Linkages

can be designed to change the direction of a force or make two or more objects move at the same

time. Many different fasteners are used to connect linkages together yet allow them to move

freely such as pins, end-threaded bolts with nuts, and loosely fitted rivets. There are two general

classes of linkages: simple planar linkages and more complex specialized linkages; both are

capable of performing tasks such as describing straight lines or curves and executing motions at

differing speeds. The names of the linkage mechanisms given here are widely but not universally

accepted in all textbooks and references.

Linkages can be classified according to their primary functions:

ed to the frame

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2.2 SIMPLE PLANAR LINKAGES

Four different simple planar linkages shown in Fig. 8 are identified by function:

Reverse-motion linkage:

Fig. 2, can make objects or force move in opposite directions; this can be done by

using the input link as a lever. If the fixed pivot is equidistant from the moving pivots, output

link movement will equal input link movement, but it will act in the opposite direction. However,

if the fixed pivot is not centered, output link movement will not equal input

link movement. By selecting the position of the fixed pivot, the linkage can be designed to

produce specific mechanical advantages. This linkage can also be rotated through 360°.

Push-pull linkage:

Fig. 8b, can make the objects or force move in the same direction; the output link

moves in the same direction as the input link. Technically classed as a four-bar linkage, it can be

rotated through 360° without changing its function.

Figure 2 Functions of four basic planar linkage mechanisms

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Parallel-motion linkage:

Fig. 2, can make objects or forces move in the same direction, but at a set distance

apart. The moving and fixed pivots on the opposing links in the parallelogram must be

equidistant for this linkage to work correctly. Technically classed as a four-bar linkage, this

linkage can also be rotated through 360° without changing its function. Pantographs that obtain

power for electric trains from overhead cables are based on parallel-motion linkage. Drawing

pantographs that permit original drawings to be manually copied without tracing or

photocopying are also adaptations of this linkage; in its simplest form it can also keep tool trays

in a horizontal position when the toolbox covers are opened.

Bell-crank linkage:

Fig. 2, can change the direction of objects or force by 90°. This linkage rang doorbells

before electric clappers were invented. More recently this mechanism has been adapted for

bicycle brakes. This was done by pinning two bell cranks bent 90° in opposite directions together

to form tongs. By squeezing the two handlebar levers linked to the input ends of each crank, the

output ends will move together. Rubber blocks on the output ends of each crank press against the

wheel rim, stopping the bicycle. If the pins which form a fixed pivot are at the midpoints of the

cranks, link movement will be equal. However, if those distances vary, mechanical advantage

can be gained

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2.3 CRANK-ROCKER MECHANISM FOR BOX TRANSPORT MECHANISM

The four bar linkage is the simplest and often times, the most useful mechanism. As we

mentioned before, a mechanism composed of rigid bodies and lower pairs is called

a linkage (Hunt 78). In planar mechanisms, there are only two kinds of lower pairs --- revolute

pairs and prismatic pairs.

The simplest closed-loop linkage is the four bar linkage which has four members, three

moving links, one fixed link and four pin joints. A linkage that has at least one fixed link is a

mechanism.

Figure 3 Crank rocker mechanism

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This mechanism has four moving links. Two of the links are pinned to the frame which is

not shown in this picture. In Sims Design, links can be nailed to the background thereby making

them into the frame.

How many DOF does this mechanism have? If we want it to have just one, we can

impose one constraint on the linkage and it will have a definite motion. The four bar linkage is

the simplest and the most useful mechanism.

Reminder: A mechanism is composed of rigid bodies and lower pairs called

linkages (Hunt 78). In planar mechanisms there are only two kinds of lower pairs: turning pairs

and prismatic pairs.

2.4 FUNCTIONS OF LINKAGES

The function of a link mechanism is to produce rotating, oscillating, or reciprocating

motion from the rotation of a crank or vice versa (Ham et al. 58). Stated more specifically

linkages may be used to convert:

1. Continuous rotation into continuous rotation, with a constant or variable angular velocity

ratio.

2. Continuous rotation into oscillation or reciprocation (or the reverse), with a constant or

variable velocity ratio.

3. Oscillation into oscillation, or reciprocation into reciprocation, with a constant or variable

velocity ratio.

Linkages have many different functions, which can be classified according on the

primary goal of the mechanism:

Function generation: the relative motion between the links connected to the frame,

Path generation: the path of a tracer point, or

Motion generation: the motion of the coupler link.

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2.5 FOUR LINK MECHANISMS

One of the simplest examples of a constrained linkage is the four-link mechanism. A

variety of useful mechanisms can be formed from a four-link mechanism through slight

variations, such as changing the character of the pairs, proportions of links, etc. Furthermore,

many complex link mechanisms are combinations of two or more such mechanisms. The

majority of four-link mechanisms fall into one of the following two classes:

1. The four-bar linkage mechanism, and

2. The slider-crank mechanism.

Definitions:

In the range of planar mechanisms, the simplest group of lower pair mechanisms are four

bar linkages. A four bar linkage comprises four bar-shaped links and four turning pairs as shown

in figure 4.

Figure 4 Four bar linkage

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The link opposite the frame is called the coupler link, and the links which are hinged to

the frame are called side links. A link which is free to rotate through 360 degree with respect to a

second link will be said to revolve relative to the second link (not necessarily a frame). If it is

possible for all four bars to become simultaneously aligned, such a state is called a change point.

Some important concepts in link mechanisms are:

1. Crank: A side link which revolves relative to the frame is called a crank.

2. Rocker: A side link which does not revolve is called a rocker.

3. Coupler: The link which connect the crank and rocker are called as coupler.

4. Crank-Rocker mechanism: In a four bar linkage if one of the side link revolve and other

side link oscillate then the mechanism known as Crank-Rocker Mechanism where shortest link is

the input link (crank). (fig 4-a)

5. Rocker-Crank Mechanism: if the shortest link is the output link (follower) then the

mechanism known as Rocker-Crank Mechanism.

6. Double-Crank mechanism: In a four bar linkage, if both of the side links revolve, it is

known as Double-Crank Mechanism where the shortest link is the ground link (frame).

7. Double-Rocker mechanism: In a four bar linkage, if both of the side links rock, it is

known as Double-Rocker Mechanism where the shortest link is the floating link (coupler).

Fig 4-a fig 4-b fig 4-c

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WORKING PRINCIPLE:

Crank-Rocker Mechanism: A 4-bar linkage mechanism has a crank that rotates at a

constant angular speed. The crank is connected to the coupler which is connected to the

rocker. The frame does not move.

Fig 5 crank rocker

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Straight-Line Walking Beam Eight-bar Transport Mechanism:

Fig 6 Walking Beam

Info: The walking beam (in blue) pushes articles (in pink) forward, and the material is

left stationary in the return stroke of the walking beam until the next cycle. The

mechanism is for moving articles with intermittent advancement. The eight-bar

mechanism allows moving more than one article, as compared to four bar walking beam.

Source: This Working Model file is adapted from Figure P3.7 on p.150 in Design of

Machinery, 3rd ed. by Norton, R.L., McGraw-Hill, 2004.

Credits: This Working Model file was first developed by Jie (Jeff) Yang.

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2.6 CLASSIFICATION

Before classifying four-bar linkages, we need to introduce some basic nomenclature.

In a four-bar linkage, we refer to the line segment between hinges on a given link as a bar where:

s = length of shortest bar

l = length of longest bar

p, q = lengths of intermediate bar

Grashof's theorem states that a four-bar mechanism has at least one revolving link if

s + l <= p + q

(5-1)

And all three mobile links will rock if

s + l > p + q

(5-2)

The inequality 5-1 is Grashof's criterion.

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All four-bar mechanisms fall into one of the four categories listed in Table 5-1:

Case (l + s varies p + q) Shortest Bar Type

1 < Frame Double-crank

2 < Side Rocker-crank

3 < Coupler Double rocker

4 = Any Change point

5 > Any Double-rocker

Table 1 Classification of Four-Bar Mechanisms

From Table 5-1 we can see that for a mechanism to have a crank, the sum of the length of

its shortest and longest links must be less than or equal to the sum of the length of the other two

links. However, this condition is necessary but not sufficient. Mechanisms satisfying this

condition fall into the following three categories:

1. When the shortest link is a side link, the mechanism is a crank-rocker mechanism. The

shortest link is the crank in the mechanism.

2. When the shortest link is the frame of the mechanism, the mechanism is a double-crank

mechanism.

3. When the shortest link is the coupler link, the mechanism is a double-rocker mechanism.

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2.7 TRANSMISSION ANGLE

In Figure 5, if AB is the input link, the force applied to the output link, CD, is

transmitted through the coupler link BC. (That is, pushing on the link CD imposes a force on the

link AB, which is transmitted through the link BC.) For sufficiently slow motions (negligible

inertia forces), the force in the coupler link is pure tension or compression (negligible bending

action) and is directed along BC. For a given force in the coupler link, the torque transmitted to

the output bar (about point D) is maximum when the angle between coupler bar BC and output

bar CD is /2. Therefore, angle BCD is called transmission angle.

(5-3)

Figure 7 Transmission angle

When the transmission angle deviates significantly from /2, the torque on the output

bar decreases and may not be sufficient to overcome the friction in the system. For this reason,

the deviation angle =| /2- | should not be too great. In practice, there is no definite upper

limit for , because the existence of the inertia forces may eliminate the undesirable force

relationships that is present under static conditions.

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2.8 ANALYSIS

FOR A GIVEN DISPLACEMENT DETERMINE THE RADIUS OF CRANK

Fig 8 mechanism

In the given fig value of d is the predetermined value and we have to determine the

crank radius r for a given radius value of rocker R

Let the oscillation of rocker is Q degree at point B

From the triangle ABC

d = 2 AC

d = 2 R Sin (Q/2) 1

Q/2 = Sin-1(d/2R)

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Q = 2 Sin-1(d/2R)

From Crank and Rocker motion

2 r = R*Q*3.14321/180

On putting the value of Q from equation 1, we get

r = (R*3.14321/180)* Sin-1(d/2R)

Example: Calculate the dimension (radius) of crank for displacement of 215 mm at the rocker

radius of 250 mm.

Solution:

Given that:

R = 250 & d = 215

Put the value of R & d in equation 3

r = (250*3.14321/180)* Sin-1(215/2*250)

r = 111.18 Ans.

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DETERMINING DEGREE OF FREEDOM:

The minimum number of independent variables required to define the position and

motion of the system is known as degree of freedom of the system.

OR

Degree of freedom is the number of input required to get constrained output in a chain.

F = 3(L - 1) - 2J - H

Where

F = degree of freedom

L = no of links

J = no of binary joint

H = no of higher pair

Hence,

F = 3(8 - 1) - 2*10 - 0

F = 1

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CHAPTER 3

3.1 MATERIAL AND DIMENSIONS

All the links are made up of MDF sheet and structure made up of solid wooden block.

The dimension of the different links are as bellow:

Fig 9 Base structure

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Figure 10 Transporting link & Connecting rod

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Figure 11 Couplers

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Figure 12 Crank & Rocker

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3.2 TOOLS

MDF Wooden plate Wooden plate cutter

Welding machine Lathe Machine

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Drill machine Electric motor

Iron angles

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Steel file tool measuring tape

Vices Cutting shearing pliers

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3.3 PROCEDURE

1. First of all we have prepared the drawing for the machine transporter machine.

2. Then we make the measurement for the bed of the box transport machine.

3. We took the wooden block and cut them in the given measurements using the cutting

machine.

4. Then we took that pieces and fitting them in the prepared shaped drawing.

5. After making the fit of wooden block bed for the machine was ready.

6. Then we took the MDF sheet plate and then taking the measurement of box transport

machine we cut the pieces in the given length.

7. After cutting the plate in the given size we put a shaft in the lathe machine for giving it

the shape of shaft.

8. After preparing the shaft, hanger and crank we take it over the drill machine to make the

holes in them as the given dimension in the drawing.

9. After this we had prepared the shaft which is going move the boxes to the next level with

using it edges on the top of it. We cut the MDF sheet plate in the given dimensions and

then edges also, after cutting we make the fitting to attach these edges with the plate on

the given distance dimensions.

10. Now all of the things for the machine are prepared.

11. On this step we took the electric motor and fix that on the bed of the machine on the

given place.

12. After fixing the motor we fixed the crank with it from one side and other side was

attached to the shaft 1.

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13. Then we took the hanger link and attach it with the shaft 1, while the other edge of the

hanger link is attached to the shaft 2.

14. Then both of the shafts were attached to the transporting shaft.

15. Two other hanger links was also attached to the shafts.

16. Other two hanger link and transporting shaft was attached to the top of the bed in the

bearing gear.

17. Out box transporting machine is ready now.

18. We give the current to the electric motor and put the boxes on the top of the machine for

testing it.

19. It was working well and boxes are moving to the next level.

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CHAPTER 4

4.1 LOGIC

The Box transporting machine is a new skill that we have learned to make a Box

transporting machine. At the same time, we learn to use a right tools and materials when doing

work at Box transporting machine. Box transporting machine is also giving us more skills and

preparation when we work outside later. When we see a result from the work that we have done

together, we are very grateful when we have finish our work in a sharp time that have given by

our lecturer.

The talent that our lecturer have given to us is bring us to a new experience about Box

transporting machine. These practical also give us advantage when we work together with our

team and we also can learn many information through share knowledge together.

4.2 FUTURE WORK

APPLICATION:

Transferring the boxes from one place to another for the requirement of worker within the

industry.

Heavy tools easily transport to one work station to another work station.

Creating a balance line in the assembly line.

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What is assembly-line balancing?

To a workstation within an assembly line in order to meet the required production rate

and to achieve a minimum amount of idle time.

Line balancing is the procedure in which tasks along assigning each task the assembly

line are assigned to work station so each has approximately same amount of work.

Steps FOR Balancing an Assembly Line:

1. List the sequential relationships among tasks and then draw a precedence diagram.

2. Calculate the required workstation cycle time.

3. Calculate the theoretical minimum number of workstations.

4. Choose a primary rule that will determine how tasks are to be assigned to workstations.

5. Beginning with the first workstation, assign each task, one at a time, until the sum of the

task times is equal to the workstation cycle time or until no other tasks can be assigned

due to sequence or time restrictions.

6. Repeat step 5 for the remaining workstations until all the tasks have been assigned to a

workstation.

7. Evaluate the efficiency of the line balance.

8. Rebalance if necessary.

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Unbalanced Line and its Effect:

High work load in some stages (Overburden).

Maximizes wastes (over-processing, inventory, waiting, rework, transportation, motion).

High variation in output.

Restrict one piece flow.

Maximizes idle time.

Poor efficiency.

Balanced Line and its Effect:

Promotes one piece flow.

Avoids excessive work load in some stages (overburden).

Minimizes wastes (over-processing, inventory, waiting, rework, transportation, motion).

Reduces variation.

Increased Efficiency.

Minimizes idle time.

W orkS ta tion 1

W orkS ta tion 4

W orkS ta tion 3

W orkS tation 2

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How Can Balancing line help in Organization?

Time Saving.

Money Saving (Time Is Money, make changes in virtual world).

Simplifies complex assembly line balancing problems.

Increased efficiency.

Increased productivity.

Potential increase in profits and decrease in costs.

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CHAPTER 5

CONCLUSION

In this project, we learn about how to prepare the Box transporting machine. Other than

that we also have been teach by our lecturer how to use the lathe machine. Besides that, our

teacher always remains us to stay alert in safety while doing a work before and after finish the

practice. Conclusion is, we want to thanks to lecturer and my friend during learning of Box

transporting machine. However, these practical we will never ever forget because these talents

are bring us to learn new things in our studying at this college.

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REFRENCES

Source: This Working Model file is adapted from Figure P3.7 on p.150 in Design of

Machinery, 3rd ed. by Norton, R.L., McGraw-Hill, 2004.

Credits: This Working Model file was first developed by Jie (Jeff) Yang.

http://www.mekanizmalar.com/transport01.html

http://projectseminars.org/report-box-transport-mechanism-project-report-in-pdf

http://seminarprojects.com/s/box-transport-mechanism

https://www.youtube.com/watch?v=tDLof06nBjU