A

PROJECT REPORT
ON

“Design the transmission system for an overhead crane assuming

Submitted by: Guided by:

Session 2017-2018
DEPARTMENT OF MECHANICAL ENGINEERING
BHILAI INSTITUTE OF TECHNOLOGY
Bhilai House, G.E. Road, Durg – 491001(C.G.), India
 CERTIFICATE

This is to certify that the mini project work entitled “Design the
transmission system for an overhead crane assuming suitable
data” has been carried out by BE 6th SEMESTER Students during
the session Jan.-May 2018, Bhilai Institute Of Technology (BIT)
Durg(C.G.), and has been prepared under my guidance.

Project guide:
Dr. (Mrs.) Shubhrata Nagpal
Professor (Mechanical Engineering)
 ACKNOWLEDGEMENT
This Project Work is a combined effort of all the team members under
the able leadership of a project guide.
We express our sincere thanks to Dr. (Mrs.) Shubhrata Nagpal, for
giving us the opportunity to study on the topic “Design the transmission
system for an overhead crane assuming suitable data”
We would like to extend our gratitude to Dr. Arun Arora (Principal, BIT
Durg) for providing us with such an opportunity to show our best. We
expect that our sincere effort would bring some worth that will
encourage us for further better work in the fore coming days.

Project Members:
 Sameer Bara
 Shahrukh Khan
 Shivam Sinha
 Surya Prakash
 V. Aditya
 CONTENTS

1. INTRODUCTION
2. LITERATURE REVIEW
3. DESIGN
4. ANALYSIS
5. CONCLUSION
ABSTRACT
Machine design is a subject that helps students to study about the theory of machine and
design the mechanism. In this course, we are requested to do a group project. In this project,
students are given a task to design a Single Girder Overhead Crane Gear-Box. The task required
us to design a gear-box which consists of spur gears, rolling element bearings, shafts, keys or
press fits, seals and housing.
In order to investigate the mechanism, knowledge that we learn in static, dynamic mechanic of
material, theory of machine is used. We start with the design of the housing and determine the
length of the shaft. With that, we can then determine the factor of safety of the shaft. After we
got all the data and values, we can start to design the gear, bearing and the key. Then, we can
determine that the output key is the weakest.
Other than manual calculation, some computer program also being used to make to
progression of work faster. Those computer programs that used by student are programs that
we learned before. We used Microsoft Excel in our calculation, PTC Creo Parametric for the
design and drawing of the gears, shaft, bearings and also the housing. With the help of this
software, we can get more accurate results and a better design of the gear-box.

OBJECTIVE
The objective of the project is to allow us to have a chance to design a suitable dimension for a
gear-box that suit to be used in a Single Girder Overhead Crane Gear-Box. A good or a poor
design is depends on the safety factor. When the safety factor is too low, the mechanism will
reach failure and break. Thus, in order to achieve a successful designing of mechanism, the
mechanism must have a safety factor of 1 or higher than 1.
Other that designs the dimension, another objective of this experiment is to choose a suitable
material for this mechanism. By choosing a stronger material, a higher ultimate strength can be
obtained and consequently a higher safety can be obtained too. Another advantage of choosing
the suitable material is cost efficiency. It is better to choose a cheap material that provide
desired safety factor than choose an expensive material that provide over high safety factor
which will cause over designed.
INTRODUCTION
A crane is a type of machine, generally equipped with a hoist, wire ropes or chains, and sheaves
that can be used both to lift and lower materials and to move them horizontally. It is mainly
used for lifting heavy things and transporting them to other places. It uses one or more simple
machines to create mechanical advantage and thus move loads beyond the normal capability of
a human. Cranes are commonly employed in the transport industry for the loading and
unloading of freight, in the construction industry for the movement of materials and in the
manufacturing industry for the assembling of heavy equipment. One of the most commonly
used crane example is “single girder overhead crane”.
This type of crane is a “Top Running Overhead Cranes” or Bridge Cranes are the most effective
lifting solution as we can cover more ground for moving items. We choose the single girder
overhead crane compared to the double girder is just because it provide us with a better value
for our application, lower production cost and therefore lower price. Other than that, top
running overhead cranes are low dead weight and more headroom by using a low headroom
monorail hoist. It is the most economical solution in buildings with a span over 90 ft. Single
girder design allows us to be cost effective without reducing its performance. Over the lifetime
of the crane, we will have saved up on a new support structures as it has reduced wheel loads
which will allows us to add more lifting capabilities to our runway structure without upgrading.
A crane main functionally part is the gearbox. Gearbox is assembly of parts including the speed-
changing gears and the propeller shaft by which the power is transmitted from an engine to a
live axle. It uses gears and gear trains to provide speed and torque conversions from a rotating
power source to another device. The gearbox in a single girder overhead crane consists of a
train gear, three shafts, six bearings and three keys. Figure 1 below shows an example of a
single girder overhead crane which is a Top Running Overhead Cranes.
1) Bridge - The main travelling structure of the crane which spans the width of the bay and
travels in a direction parallel to the runway. The bridge consists of two end trucks and one or
two bridge girders depending on the equipment type. The bridge also supports the trolley and
hoisting mechanism for up and down lifting of load.
2) End trucks - Located on either side of the bridge, the end trucks house the wheels on which
the entire crane travels. It is an assembly consisting of structural members, wheels, bearings,
axles, etc., which supports the bridge girder(s) or the trolley cross member(s).
3) Bridge Girder(s) - The principal horizontal beam of the crane bridge which supports the
trolley and is supported by the end trucks.
4) Runway - The rails, beams, brackets and framework on which the crane operates.
5) Runway Rail - The rail supported by the runway beams on which the crane travels.
6) Hoist - The hoist mechanism is a unit consisting of a motor drive, coupling, brakes, gearing,
drum, ropes, and load block designed to raise, hold and lower the maximum rated load. Hoist
mechanism is mounted to the trolley.
7) Trolley - The unit carrying the hoisting mechanism which travels on the bridge rails in a
direction at right angles to the crane runway. Trolley frame is the basic structure of the trolley
on which are mounted the hoisting and traversing mechanisms.
8) Bumper (Buffer) - An energy absorbing device for reducing impact when a moving crane or
trolley reaches the end of its permitted travel, or when two moving cranes or trolleys come into
contact. This device may be attached to the bridge, trolley or runway stop.

A gear box is a machine which consists of a power source and a power transmission system,
which provides controlled application of the power. Merriam-Webster defines transmission as
an assembly of parts including the speed-changing gears and the propeller shaft by which the
power is transmitted from an engine to a live axle. Often transmission refers simply to the
gearbox that uses gears and gear trains to provide speed and torque conversions from a
rotating power source to another device. A gear train is formed by mounting gears on a frame
so that the teeth of the gears engage. Gear teeth are designed to ensure the pitch circles of
engaging gears roll on each other without slipping; this provides a smooth transmission of
rotation from one gear to the next. Transmission shafts, or just shafts, are used in virtually
every piece of rotating machinery to transmit rotary motion and torque from one location to
another part of machine.
DESIGN SPECIFICATIONS
Motor: 5 hp, with 1800 rpm
Capacity: 1360 kg. (Maximum amount of weight it can carry, plus some safety factor)
Lift height: 10 meters (Height at which the crane will be placed)
Lift speed: 10 m/min (Speed at which the weight will be lifted upwards)

We choose the “single grider overhead crane” for our project because it is the most suitable
overhead crane design for this project compared to the other design. The single girder
overhead crane is normally used in light duty load which is perfect for this project since the load
capacity is only 1360kg. Secondly, The it is the crane with the least component and simple parts
which makes it the cheapest among the other design .
The gear box design will be a gear box that have an input from a 5hp motor with a 1800rpm.
The output must be able to lift a 1360kg loads with a speed of 10m/min and a safety factor
more than one. All of the specifications are been verified in our calculations below.