FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
A gear box main shaft assembly table with fault detecting means and a method of detecting faults in a gear box main shaft assembly
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 Vishant Virupaksha Tarn bade 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 Provisional specification particularly describes the invention and the manner in which it is to be performed.

This invention relates to a gear box main shaft assembly table with fault detecting means. It is particularly though not exclusively applicable in automobile industries for gear box assembly. This device may also be used in other industries where similar operations are required.
In an automobile, gear box plays the vital function of transmitting power from the engine to^the wheels through the rear axle or transfer case. Manufacture of gear box is therefore, very critical and has to be done with utmost care and precision.
Conventional gear box has three sub-assemblies assembled in the gear box housing. They are (1) main shaft, (2) counter shaft and (3) drive shaft, out of these three sub¬assemblies, the main shaft sub-assembly plays a critical role in determining the quality and life of the gear box. In the main shaft sub-assembly needle cage bearings between the bore of the gear and the outside diameter of the synchronizing sleeve / collar bush. This operation is carried out manually. In case one or more of the needle cage bearing is not fitted during the assembly, the assembled gear box gets seized. It is therefore essential to detect the presence or absence of the needle bearings in the sub-assembly before the main shaft is ready for fiirther assembling. The existing assembly procedure which is manual does not have any fool proof method of fault detection. In case, the
operator inadvertently omits to include one or rpore j^K bearing in the assembly, seizure of the gear box is bound to occur leading to warranty problems and customer dissatisfaction.
The main object of this invention is to detect the absence of needle cage bearings prior to the final gear box assembly.

The gear box main shaft assembly table with fault detecting means according to this invention comprises a table provided with two tracks for mounting and moving completed main shaft sub-assembly thereon, each track having an actuatable proximity sensor, a pneumatically actuatable stopper cylinder, and a solenoid valve connected to a make and break relay circuit provided with audio visual signal means.
This invention also includes a method of detecting faults in a gear box main steps of mounting said shaft assembly on two tracks provided on a table top which has two proximity sensors, a pneumatically actuatable cylinder with a piston provided with stopper means, a make and break relay circuit having audiovisual signal means said circuit connected to a solenoid valve, the arrangement being such that when a faulty shaft assembly is mounted on said tracks, the proximity sensors, sense the fault to actuate the pneumatic cylinder, the piston of which provides with stopper means, stops said faulty shaft assembly from rolling out of said table, said proximity sensors also activating said solenoid valve and said relay circuit which breaks contacts to give out audio visual signals enabling manual removal of said faulty main shaft assembly from said table top.
This invention and its method of operation will now be described with reference to Figs. I, II, III, IV and V.
Figs. I and II represent schematic front and side views of the table according to this invention.
Fig. Ill represents a view of the table with the shaft assembly without any fault mounted thereon.

Fig. rV is a view of the machine when a detection shaft assembly is mounted on the tracks and Fig. V is the relay circuit diagram which gives audio visual signals in the event of fault detection.
In Figs. I and II reference numeral 1 stands for the table for gear box main shaft assembly. This table is mounted on four legs. The table top has two tracks welded thereon for facilitating the movement of the main shaft assembly. These tracks are indicated by numeral (3) and the assembled main shaft is mounted on the track for fault detection. Reference number 2 shows this assembly proximity sensors (7) are provided below the tracks which sense any abnormality or faults in the assembly mounted on the tracks. These sensors also command actuation of a pneumatically operable stopper cylinder (6) provided with a stopper means (5) positioned on its piston rod. This stopper when actuated lies in the path of the main shaft assembly. The arrow indicated by numeral (4) shows the direction of movement of the gear box assembly on the table top. Reference numeral (9) shows the solenoid valve which is electrically operated to activate the pneumatic cylinder. Arrow (8) indicates the direction of any inlet to the stopper cylinder activating valve (9). Reference numerals 10 and 11 show the down and up direction of the solenoid coil of this valve. Reference numerals (12) and (13) show audio and visual sensing means such as hooter and glowing lamp respectively.
Fig. Ill shows the position of the proximity sensors when the main shaft assembly placed on the table top does not have any fault and the needle cage bearings are all positioned within the assembly. The proximity sensors do not get activated and the stopper means of the pneumatic cylinder is not energized. The relay circuit is not broken and the signals are not given out.

In Fig. IV, the gear assembly on the table top does not have the needle cage bearing. As a result, the gear drops down and activates the proximity sensors. The pneumatic piston provided with the stopper means comes out thereby stopping the faulty main shaft assembly from rolling out of the table. The faulty work piece is then retrieved from the table to rectify the defect and then subjected to fiirther fault testing.
Fig. V indicates the circuit diagram with audiovisual signal means. When needle cage bearing is not present in the main shaft assembly mounted on the work table. Proximity sensors get actuated closing contacts 1 and 2 and contacts 4 and 5 thereby activating relays RLl and RL2 which is connected to relay RL3. Operation of RL3 closes the contacts 11, 12 which operates the relay RL4 of the solenoid of the pneumatic cylinder. This cylinder thus gets activated to push out the piston cylinder with the stopper means and prevents the faulty main shaft assembly from rolling out of the work table. Audio visual sensing means such as glowing lamp and hooter also get energised to indicate the fault in the job to enable the operator to rectify the same. Push buttons PB are provided to reset the relay once this operation is complete.
Though this invention has been described hereinbefore with a specific embodiment, alteration and modifications known to persons skilled in the art are not excluded from the scope of the appended claims.

WE CLAIM
1. A gear box main shaft assembly device with fault detecting means comprising:
- a table (1) provided with two tracks (3) for mounting and moving main
shaft sub-assembly (2) thereon,
wherein, each track (3) having:-
- an actuatable proximity sensor (7),
- a pneumatically actuatable stopper cylinder (6), and
- a solenoid valve (9)
located below it and connected to a make and break relay circuit provided with audio visual signal means(12,13).
2. The gear box main shaft assembly table as claimed in claim 1 wherein said table has a top mounted on four legs.
3. The gear box main shaft assembly as claimed in claims 1 to 3 wherein said audio visual signals means are a glow lamp (13) and a hooter (12).
4. A method of detecting faults in a gear box main shaft assembly which comprises the steps of mounting said shaft assembly on two tracks provided on a table top (1) which has two actuatable proximity sensors (7), a pneumatically actuatable stopper cylinder (6) with piston provided with stopper means (5), a make and break relay circuit having audio visual signal means (13, 12) said circuit connected to a solenoid valve (9) the arrangement being such that when a faulty shaft assembly is mounted on said tracks, the actuatable proximity sensors sense the fault to activate the pneumatic cylinder, the piston of which provided with stopper means stops said faulty assembly from rolling out of said table, said actuatable proximity sensors also activating said solenoid valve and said relay circuit which breaks to give out audio visual signal enabling manual removal of said faulty main shaft assembly from said table top.

5. A gear box main shaft assembly table with fault detecting means substantially as herein described with reference to the figures in the accompanying drawings.
6. A method of detecting faults in a gear box main shaft assembly substantially as herein described.
Dated this 29 day of December 2003