FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION Fixture and method for bush pressing and caulking operation in gear
box
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Vaij Sanjay Yashawant
Indian nationals of
TATA MOTORS LIMITED,
an Indian company having its registered office
at Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

TITLE OF INVENTION:
Fixture and method for bush pressing and caulking operation in gear box.
FIELD OF INVENTION:
This invention relates to a Fixture and method for bush pressing and caulking operation in gear box more particularly for GBS40 gear box.
BACKGROUND OF THE INVENTION:
Earlier the pressing & caulking operations of the bush into the reverse idler gear was done by using two different dollies. In the first set up, the pressing dolly was mounted on the press and the bush was pressed in the gear. After completing the bush pressing in all gears in the batch, second dolly was mounted for caulking operation and the caulking operation was done in all the gears one by one. The use of those dollies resulted in certain problems such as more cycle time, double work set up, missing of the caulking operation in few gear boxes due to human error, two press strokes for two operations and rework after wrong pressing. Again, the earlier method i.e. existing art was not providing an adequate device for pressing and caulking operation in a single press stroke
OBJECT OF THE INVENTION
The main objective of the present invention is to obviate above mentioned
drawbacks.
Another objective of the present invention is to provide an improved fixture for
bush pressing and caulking operation in gear box.
Yet another objective of the present invention is to provide an improved method for
bush pressing and caulking operation in gear box.
SUMMARY OF THE INVENTION
A fixture for bush pressing and caulking operation in gear box comprising: - an upper half and a lower half guided by pillar and bush,

- a pressing and a caulking dolly mounted with upper half in such a way that pressing dolly is mounted at front side and caulking dolly is mounted at the back side,
- two locations for pressing and caulking operation are created in a single rotary plate on the lower half and at each location one spring loaded locator is provided to locate the gear.
Two hardened round plates are provided below said rotary plate for rigid support while pressing.
A taper roller bearing is provided for the rotary plate for its rotary movement.
Locator pins are fitted inside base plates through said rotary plate.
Compression springs are provided below said locator pins.
A detent pin is fitted in a block with retainer plate provided below rotary plate to .ensure the rotation of the rotary plate by 180° in conjunction with gauge pieces.
The gauge piece is having a V shape slot for locating said detent pin.
Stoppers are mounted on spherical sides of the rotary plate to stop the rotation at desired position of the rotary plate.
Two magnets are fitted in said block to prevent said rotary plate from bouncing back after hitting the stoppers to the block.
Pressing dolly is mounted at front side of plate and caulking dolly 34 at rear side. Method for bush pressing and caulking operation in gear box comprising steps;
- the fixture is mounted on table of hydraulic press,
- the gear is placed on the frontal location and the bush is located in the
corresponding dolly and pressed in the gear,

- the rotary plate is turned 180° and to achieve the perfection in turning 180° stoppers are provided along with the magnet and detent pin,
- the second location comes to front side and the same process as describe above
- while pressing the bush in this gear at front side, the earlier gear is caulked at another location at back side and then the rotary table is turned 180° in reverse direction and the caulked gear is replaced by the new gear.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of the fixture
FIG. 2 is an isometric view of the lower half of the fixture
FIG. 3 is an isometric view of the upper half of the fixture
FIG. 4 is an exploded view of the fixture
FIG. 5 is sectional view taken at the line AA
FIG. 6 is sectional view taken at the line BB
FIG. 7 is an isometric view of the Reverse Idler Gear
FIG. 8 is an isometric view of the Bush
FIG. 9 is an isometric view of the bush and gear assembly
FIG. 10 is an isometric view of the fixture with gear and bush before pressing
operation
DETAILED DESCRIPTION
The current invention provides a method and fixture for pressing and caulking operation of the bush into the reverse idler gear of the gearbox, which permits the successful pressing and caulking operation of the bush into the reverse idler gear. Various features of the invention provide faster and easier pressing and caulking of the bush in a single press stroke.
The invention includes upper and lower half which are guided by pillar and bush. Four enclosed spring posts are provided to retain the upper half to its original position after pressing operation. The pressing and caulking dollies are mounted with the upper half. Pressing dolly is mounted at front side whereas caulking dolly is mounted at the back side. Two locations for pressing and caulking operation are

created in a single rotary plate on the lower half. At each location one spring loaded locator is provided to locate the gear. Two hardened round plates are given below the rotary plate for rigid support while pressing. A taper roller bearing is used for the rotary plate for its rotary movement.
While using this fixture, the fixture is mounted on the table of the one ton hydraulic press. The gear is placed on the frontal location and the bush is located in the corresponding dolly and pressed in the gear. Then the rotary table is turned 1800 by hand. To achieve the perfection in turning 180° stoppers are provided along with the magnet and detent pin. Now the second location comes to front side. Follow the same process as describe above. While pressing the bush in this gear at front side, the earlier gear is caulked at another location at back side. Then the rotary table is turned 180° in reverse direction and the caulked gear is replaced by the new gear and the process is continued.
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same.
LOWER HALF OF THE FIXTURE:-
Two round pillars 13 are press-fitted in the flanged bush 12 and mounted on the plate 11. The pillars are case hardened to make the surface hard and wear resistant. Four spring posts 14 are mounted on the plate at four corners. The spring post is the piece of metal pipe with the rectangular plate welded at its lower end. Four heavy compression springs 26 are inserted in the spring posts. The springs have the enough stiffness to lift up the upper half of the fixture after each bush pressing operation. A centre shaft 15 is mounted exactly at the centre of the plate and a taper roller bearing is fitted on the shaft. The inner race of the bearing is tightly fitted on the center shaft and the outer race is fitted in the rotary plate 21. Two resting pads 17 are mounted on the either side of the centre shaft on the plate and similar two resting pads are mounted on the bottom side of the rotary plate. All these four resting pads should be aligned to each other. These resting pads are case

hardened to make the surface wear resistance and provide rigid support to the rotary plate while pressing and caulking operations. Two round and hardened base plates 25 are mounted on the rotary plate and the locating pins 22 are fitted inside the base plates through the rotary plate. The locating pins are hardened. Compression springs 27 are provided below the locating pins. While pressing the bush the locating pin goes down and when the pressing operation ends it comes up by the spring. A detent pin 19 is fitted in the block 18 with the retainer plate 20. The detent pin ensures the rotation of the rotary plate by 180° in conjunction with the gauge pieces 24. The gauge piece is having a V shape slot for locating the detent pin. The additional stoppers are mounted on the spherical sides of the rotary plate which help to stop the rotation at the desired position of the rotary plate. Two magnets are fitted in the block 18 which prevent the rotary plate from bouncing back after hitting the stoppers to the block.
UPPER HALF OF THE FIXTURE:-
Four spring post covers 31 are mounted on the plate at the corner. The spring post covers are made up of the pipe and a small plate welded at its upper end. The pipe internal diameter is slide fit to the outer diameter of the spring post mounted on the lower half. Pressing and caulking dollies are mounted on the plate. The pressing dolly 33 is mounted at the front side of the plate and caulking dolly 34 at rear side. Both the dollies are aligned with the center of the base plates on lower plate. Two bush holders 32 along with bush bearings 35 are mounted on the lower plate. The bush bearings are press fitted in the bush block and aligned with the guide pillar on the lower plate.
The upper half of the fixture is clamped to the ram plate of the hydraulic press and the fixture is ready for pressing and caulking operations.
DETAILED DESCRIPTION OF THE PRESSING AND CAULKING METHOD
The bush is engaged with the pressing dolly. The pressing dolly has a spring loaded pin which prevents the bush from falling down. The gear is located in the

locating pin on the lower half. The upper half of the fixture is taken down to press the bush inside the gear.
After completion of the pressing operation, the upper half of the fixture is lifted up. The locating pin rises up the gear. Since the step has been provided on the locating pin, it partially engages with the gear while rising up gear.
The rotary plate is rotated by 180°. The gear goes to rear side and another locating pin comes to the front side. Another gear is located in the locating pin at front side and above same process is repeated for pressing the bush in it.
When the bush is getting pressed in the gear at front side, .same time the caulking operation is done at the rear side.
The rotary plate is rotated by 180° in reverse direction. The caulked gear comes at front side. The gear is taken out from the locating pin. Same process is repeated for next gears. Thus both the operations are completed in one press stroke.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

CLAIMS
I claim:
1. A fixture for bush pressing and caulking operation in gear box comprising:
- an upper half and a lower half guided by pillar and bush,
- a pressing and a caulking dolly mounted with upper half in such a way that pressing dolly is mounted at front side and caulking dolly is mounted at the back
side,
- two locations for pressing and caulking operation are created in a single rotary
plate on the lower half and at each location one spring loaded locator is provided to
locate the gear.
2. The fixture for bush pressing and caulking operation in gear box as claimed in claim 1 wherein, two hardened round plates are provided below said rotary plate for rigid support while pressing.
3. The fixture for bush pressing and caulking operation in gear box as claimed in claim 1 wherein, a taper roller bearing is provided for the rotary plate for its rotary movement.
4. The fixture for bush pressing and caulking operation in gear box as claimed in claim 1 wherein, locator pins are fitted inside base plates through said rotary plate
5. The fixture for bush pressing and caulking operation in gear box as claimed in claim 1 and 4 wherein, compression springs are provided below said locator pins.
6. The fixture for bush pressing and caulking operation in gear box as claimed in claim 1 wherein, a detent pin is fitted in a block with retainer plate provided below

rotary plate to ensure the rotation of the rotary plate by 1800 in conjunction with gauge pieces.
7. The fixture for bush pressing and caulking operation in gear box as claimed in claim 6 wherein, said gauge piece is having a V shape slot for locating said detent pin,
8. The fixture for bush pressing and caulking operation in gear box as claimed in claim 1 wherein, stoppers are mounted on spherical sides of the rotary plate to stop the rotation at desired position of the rotary plate.
9. The fixture for bush pressing and caulking operation in gear box as claimed in claim 1 and 6 wherein, two magnets are fitted in said block to prevent said rotary plate from bouncing back after hitting the stoppers to the block.

10. The fixture for bush pressing and caulking operation in gear box as claimed in claim 1 wherein, pressing dolly is mounted at front side of plate and caulking dolly 34 at rear side.
11. Method for bush pressing and caulking operation in gear box comprising steps:

- the fixture is mounted on table of hydraulic press,
- the gear is placed on the frontal location and the bush is located in the corresponding dolly and pressed in the gear,
- the rotary plate is turned 180° and to achieve the perfection in turning 180° stoppers are provided along with the magnet and detent pin,
- the second location comes to front side and the same process as describe above
- while pressing the bush in this gear at front side, the earlier gear is caulked at another location at back side and then the rotary table is turned 180° in reverse direction and the caulked gear is replaced by the new gear.

12. The fixture for bush pressing and caulking operation in gear box substantially as herein above described and as illustrated in accompanying drawings