vocational training project at Tata motors, jamshedpur. heft cabin fixture is where cross members are attached to longitudinal members

1. Tata Motors
PRESENTED BY
• SAURABH SINGH
• ANURAG AMBASTHA
• AKASH PANDEY
GUIDED BY
Mr Rakesh Cheeli
Manager- Maintenance
Frame Factory

2. Company Profile
TATA MOTORS is India’s largest automobile company. It is the leader by
far in commercial vehicle, and the second largest in passenger car
market with winning products in the compacts, mid-size car, and utility
vehicle segments. The company is the world fifth largest and medium
and heavy bus manufacturer

3. • Company was established in 1945, TATA MOTORS present indeed cuts
across the length and breadth of India. Over 4 million TATA MOTOR vehicle
ply on Indian roads, since the first rolled out in 1954. The company’s
manufacturing base is spread across Jamshedpur, Pune, Pantnagar, Sanand
and Lucknow, supported by a nation-wide dealership, sales, services and
spare parts network comprising about 3500 touch points. The company
also has a strong auto finance operation, TATA MOTORS finance.

4. Frame
It is the structural centre of the vehicle for carrying load, to furnish
supports for transmission system, the body, and other units such as shock
absorbers, springs, shackles
Auxiliary parts required for load carrying and vehicle transmission are
fastened to frame.

5. Diagram representing a typical frame

6. Above figure shows the longitudinal members A and the cross members B for a general vehicle.
C are the brackets supporting the body. E1 are the dumb irons to act as bearings for spring shackles.
Brackets E are meant for mounting the springs.
The extension of the chassis frame ahead of the front axel is called front overhang ,whereas its extension beyond the rear axel
is called the rear overhang.

7. FIXED
Hydraulic
connection
PUSHERS
EXPANDERS
movable
HEFT CABIN FIXTURE(Line 1)

8. • Every pusher has two connections for hydraulic system.
• Expanders are movable horizontally as well as laterally..
• One side of the pushers is fixed and the other side is movable.
• Here the cylinder used is a Double acting cylinder*.
• Double Acting Cylinder: It is a cylinder in which the working fluid
acts alternately on both side of the piston.
HEFT CABIN FIXURE CONSTRUCTION

9. Bend in frames
• During the assembling of frame, there may be some deviation from
what we require and may cause some functional defects.
• In frames, they are usually characterised by exceeding of tolerance
beyond a certain level.
• In our case the acceptable tolerance is from -5mm to +5mm.
The possible causes for bending may be:
• The side members may be bent.
• Cross members may be buckled.
• Some rivets may be loose or broken.

10. PROJECT

11. Problem Statement
Synchronization hydraulic cylinders of *Heft Cabin Fixture in order to
eliminate problem of bend in frames
*Heft Cabin Fixture : Here long members, cross members and
reinforcements are fasten together through nuts, bolts and rivets

13. Sr. No Possible Causes Validation Method Result
1. Different suppliers provide cross-
members with different tolerances
Self-observation and operators’
interview
These defects contribute to
bending
2. Different placement of frame on the
fixture
Self-observation Workers adjust the machines
accordingly and have no effect
on bending
3. Use of plates to ensure contact between
pushers and long members
Self-observation and operators’
interview
They do not contribute
significantly to bending

14. 4. Over tightening of bolts Self-observation and operators’
interview
It does not have major effect on
bending.
5. Unskilled workers Self-observation and operators’
interview
Attributed to some new and
unexperienced workers
6. Lack of knowledge on WIS Workers’ interview It contribute to bending
7. Single common valve for all pushers Analysis of hydraulic system It is a major reason so separate
DC valves for different pusher
should be used
8. Elasticity of spring reduces with time Operators’ interview Lead to non-synchronization of
cylinders which in turn results
into bending

15. Corrective Measures
• Following measures can be suggested to counter the problem of non
synchronization of hydraulic cylinders:
1.Using external mechanical hardware
• This will include racks and pinions, crankshafts, cables and pulleys and
chains and sprockets.
• Accuracy will depends on strength of hardware and the position of
the load
• They can operate at any place without getting out of phase

16. 2.Using Servo valve
• Most accurate method
• Independently control each cylinder with electronic position feedback
and compare each actuator’s position with others
• Also works well with cylinders that never go to a home position
3.Installation of separate flow control valve for different
pushers

17. Use of flow control
valves
Use of external
Mechanical Hardware
• Complicated and
cumbersome method
• Labour intensive
Use of servo valves
• More accurate
• Very expensive
• Simpler method
• Economical
• Accurate
Having a look on the pros and cons of all three methods of synchronising hydraulic
cylinders of the Heft Cabin Fixture, use of flow control valve is a best option by the virtue
of being simpler and economical with appreciable accuracy. It has been implemented and
is under observation.