FORM-2
THE PATENT ACT. 1970
(39 OF 1970)
&
THE PATENT RULES, 2003
PROVISIONAL SPECIFICATION
[SECTION 10; RULE 13]


"IMPROVED SYNCHROMESH MANUAL SHIFT GEAR BOX FOR A
VEHICLE"

VOLTAS LIMITED, AN INDIAN LIMITED LIABILITY COMPANY INCORPORATED UNDER THE INDIAN COMPANIES ACT, 1913, HAVING OUR REGISTERED OFFICE AT VOLTAS HOUSE 'A' DR. BABASAHEB AMBEDKAR ROAD, CHINCHPOKLI, MUMBAI 400033
THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION:


INTRODUCTION
This invention relates to an improved synchromesh manual shift gear box for a vehicle. More particularly, it relates to an improved synchromesh manual gear box for an industrial vehicle such a forklift truck.
PRIOR ART
Synchromesh gear box have the advantage of offering smooth, noise free gear shifting and easy operation as compared to a conventional sliding mesh manual shift gear box and therefore are in use in light vehicles as also in heavy vehicles like Lorries and Buses which generally have more forward gears i.e. more than one gear allowing the vehicle to move/travel in forward direction at varying speeds including at higher speed but have only one un-synchromesh reverse gear i.e. only one gear allowing the vehicle to move/travel in backward direction, preferably at slow speed. Such vehicles are designed to travel at various speeds including at high speeds in the forward direction. However, as such vehicles are not required to travel at various speeds and particularly at high speeds in the reverse or backward direction, they are provided with only one un-synchromesh gear to move the vehicles in the reverse or backward direction at slow speed. In contrast a forklift truck travels half the time in forward direction and the remaining half time in reverse/backward direction and hence it is designed to have more than one number of reverse gears or at times equal number of forward and reverse gears. Also it is designed to travel only at slow speed both in forward and reverse direction as it is primarily used inside a factory or a warehouse which is full of people, machinery, raw-material or unfinished/ finished goods and therefore it has to be driven very carefully at slow speed. Often material handling


vehicles cris cross path of the forklift truck. It is also required to turn right, left, backward and forward all the time. The gear box of fork lift truck is therefore designed to be rugged and compact and at the same time having more than one number of gears for the reverse/backward movement if not equal number of gears in forward as well as reverse direction.
Due to the above basic differences between light vehicles or heavy vehicles like lorries, buses, etc. on one hand and fork lift truck on the other hand, a synchromesh gear box known in the prior art and used in the aforesaid other automotive vehicles cannot be adopted in the forklift truck. Further, though desired forklift truck known in the prior art is not provided with Synchromesh gear box in the reverse direction.
SUMMARY OF THE INVENTION
According to this invention, a synchromesh gear box has two similar clusters of gear instead of one cluster of gear in synchromesh manual shift gear box, hereinafter called the gear box, and known in the prior art. This provides equal or near equal torque transmission capacities in forward as well as reverse directions.
In a preferable embodiment there are two locking arrangements viz. Pin and Groove type and Ball and Spring type, to lock the gears in neutral as well as forward/reverse positions, unlike a locking arrangement used in the gear boxes known in the prior art. In the gear box according to this invention the rods and forks both move to change the gears, unlike in the gear box known in the prior art wherein the rods are stationary and


only the forks move to change the gear. This makes the aforesaid double locking system possible in the gear box according to this invention.
Further, the gear box according to this invention comprises of the Hypoid Gear. Pinion and the Differential (that drives the wheels) all integrated with the gear box. unlike in the prior art, wherein the Hypoid Gear, Pinion and Differentia! all are not integrated with the gear box but are separately located. Consequently, the same oil can be used for lubricating the gears as well as the differential in the gear box according to this invention, unlike in the gear box known in the prior art.
Still further, in the gear box according to this invention, the input gear shaft which connects the engine to gear box for the purpose of power transmission, is integrated with the gear box and it is independent of the main shaft, unlike in the gear box known in the prior art wherein the input gear shaft is not integrated with the gear box but is directly associated with the main shaft.
In a preferable embodiment according to this invention, the gear shifting linkage for the forward as well as reverse gears is integrated on the top plate of the gear box to make it compact, unlike in the gear box known in the prior art wherein the gear shifting linkage is complicated and elaborate. Further, the axle of the fork lift truck according to this invention, is integrated with the gear box and is provided with an arrangement for mounting the mast which lifts the payload to be carried by the fork lift truck, unlike in the fork lift trucks known in the prior art.


In yet another preferable embodiment according to this invention, the clutch and/or fluid coupling housing is integrated with the gear box, unlike in the gear box known in the prior art where the clutch and/or fluid housing are not integrated with the gear box but is a part of the engine.
Further, the input gears of the gear box according to this invention, are spur gears. unlike the helical input gears in the gear box known in the prior art.
DESCRIPTION OF THE INVENTION
The invention will now be described with reference to the accompanying drawings wherein the same numerals are used to denote the same parts. However, the said drawings are only illustrative and in no way limit the invention.
In the accompanying drawings:
Figure I shows exploded perspective view of the gear box.
Figure 2 shows exploded perspective view of forward cluster of gears (input) in the gear box.
Figure 3 shows exploded perspective view of reverse cluster of gears (input) in the gear box.
Figure 4 shows exploded perspective view of cluster of gears (output) together with the differential assembly in the gear box.


Figure 5 shows perspective view of gear shifting assembly with two locking arrangements, viz. Pin and Groove type and Ball and Spring type.
Figures 6(A), 6(B) and 6(C) show top view of the pin and groove type locking arrangement in the gear box, in its neutral. lst gear and 2nd gear positions, respectively.
Figures 7(A), 7(B) and 7(C) show top perspective view of ball and spring type locking arrangement in the gear box. in its neutral. lst gear and 2nd gear positions, respectively.
Figure 8 shows top perspective view of main housing of the gear box containing forward and reverse cluster of gears (input).
Figure 9 shows perspective view of cluster of gears (output) and the differential assembly integrated with the gear box.
Figure 10 shows perspective view of axle, housing cluster of gears (output) and the differential gear assembly(both not seen in this figure but shown in fig. 9). having mast mounting arms to lift the pay load to be carried out by the fork lift, integrated with the gear box.
Figures 11 (A) and 11(B) show perspective view of the lower casing of the gear box.


Figure 12 shows perspective view of the main housing of the gear box with the transmission drive pinion shaft and forward and reverse clusters of gears (input).
Figure 13 shows front view of two forks of the gear box.
Figure 14 shows perspective view of the wall extension built on the axle of the gear
box.
Figure 15 shows perspective view of the top cover of the gear box. Figure 16 shows perspective view of the main casing of the gear box.
Figure 17 shows sectional view of the main casing of the gear box shown in figure 16.
along line A-A.
In figure 1, the gear box assembly has main casing(I) comprising of transmission gear box housing with pedestal cap, forward cluster of gears (input) (2), differential bearing retainer (3), bearing single row radial ball (4). transmission drive pinion shaft (5), bearing.support cap (6), hexagonal head screw (7), lower casing (8), axle (9), oil level plug (10), magnetic drain plug (11); air vent (12), clutch throughout lever & bearing assembly (13), hexagonal head bolt (14), hexagonal head screw (15), top cover (16), interlock assembly (17), hexagonal head strew (18), oil plug (19), gear shifter assembly (20), gear shifter bar left hand (21), gear shifter bar right hand (22),


ball (23), spring (24), spring follower (25), interlocking pin (26), bushing (27), clutch throughout shafts (28) hexagonal head, (29), lube fitting (30), vent cover (31). lock washer (32), hexagonal head screw (33), lever (34). hexagonal head screw (35). hexagonal nut (36), gear shifter fork right hand (37), gear shifter fork left hand (38), set screw (39), cotter pin (40), dowel pin (4l),cluster of gears (output) and the differential assembly(42),hexagonal head screw (43), hexagonal screw (44) and reverse cluster of gears (input) (45).
In figure 2, the forward cluster of gears (input) (2), has transmission intermediate shaft (2A), bearing single row radial ball (2B), synchronizing sleeve (2C), double needle roller bearing (2D) and (2T), transmission high gear (2E). synchronizing cones (2F) and (2S). collor bush (2G), transmission low gear (2H), snap ring (2J), gear changer (2K), changer locking block (2L), changer locking spring (2M), changer locking pin (2N), transmission intermediate gear (2P) and gear stopper (2R).
In figure 3. the reverse cluster of gears (input) (45), has transmission intermediate shaft (45A), bearing single row radial ball (45B), synchronizing sleeve (45C), double needle roller bearing (45D) and (45T), transmission high gear (45E), synchronizing cones (45F) and (45S), collor bush (45G), transmission low gear (45H). snap ring (45J), gear changer (45 K). changer locking block (45 L), changer locking spring (45M), changer locking pin (45N), transmission intermediate gear (45P) and gear stopper (45R).


In figure 4, cluster of gears (output) and the differential assembly (42) has ring (hypoid)
gear (42A), pinion (42B). pinion bearings (42C) and (42G), pinion shaft spacer (42D), snap ring (42E), key (42F), keyed washers (42H) and (42J), bearing lock nut (42K), transmission dual gear (42L), differential bearing (42M), hexagonal head screws (42N), and side gear thrust washer (42R), differential case short (42S), differential case long (42T), bevel gear (42U), pinion thrust washer (42V), differential spider (42W) and bevel gear (42X).
In figure 5, gear shifting assembly (20) is provided with ball and spring locking arrangement L-l(Ref figure 7) and pin and grove locking arrangement L-2 (Ref figure 6) and gear shifter lever (20A). In the said figure, the arrow marked A-B shows movement of gear shifter bars (21) and (22) with gear shifter forks (37) and (38).
In figure 6, pin and groove locking arrangement L-2 comprises of gear shifter bar left hand (21) having grooves (21 A). (21B) and (21C) on the top and (21D) on the inner side and the gear shifter bar right hand (22) having grooves (22A)T (22B) and (22C) on the top and (22D) on the inner side.
In figure 7, ball and spring locking arrangement L-l comprises of gear shifter bars left hand (21) and right hand (22) having on top balls (23B) and (23A) respectively and on inner side balls (23D) and (23C) respectively.


In figure 9. cluster of gears (output) and the differential assembly (42) is integrated with the gear box wherein connecting flange fluid coupling/clutch housing is made up of upper part (16 A) and lower part (8A) which is bolted together.
In figure 10, axle (9) has mast mounting arms 9A-9A which carry the pay load (not shown) of the fork lift truck.
In figure i 1 A & I IB, (8B) are housing for supporting bearings single row radial ball (2B) and (45B) and pinion bearing (42G). The said housings are closed at (8C) inside the lowercasing (8).
In figure 12, X and Y are the limited width and length of the main gear box housing within which the assembly of transmission drive pinion shaft (5) and forward and reverse clusters of gears (input) (2) and (45) are required to be accommodated.
In figure 13, gear changer (2K) is in forward cluster of gears (input) (2) and gear changer (45 K) is in reverse cluster of gears (input) (45) gear shifter forks (37) & (38) need lo hold {at least 90 degree to 180 degree } periphery of gear changers (2K) & (45 K) lo change the gears.
In figure 14, wall extension (9B) is built on axle (9) to serve as the gear box front end cover.
In figure 15, top cover (16) is provided with ribs (16B) to strengthen its base (16C).


In figure 16 & 17, main casing (1) of the gear box has tapered profile (IE) to minimize if s envelop and at the same time to reduce its weight.
WORKING OF THE INVENTION
Jn the neutral condition, From Engine / Flywheel the power is transmitted to transmission drive pinion shaft (5). This shaft drives the Transmission Intermediate Gear (2P), which in turns drives Transmission Intermediate Gear (45P). These gears provide drive to Transmission Intermediate Shafts (2A) & (45A) respectively. The Transmission Intermediate Gears (2P) & (45P) are sitting on Transmission Intermediate Shafts (2A) & (45A) respectively and so are the Synchronizing Sleeves (2C) & (45C) and Collor Bush (2G) & (45G). Thus Transmission Intermediate Gears (2P) & (45P) continuously rotate Transmission Intermediate Shafts (2A) & (45A) which in turn rotate Synchronizing Sleeves (2C) & (45C) and Collor Bush (2G) & (45G) respectively. The Transmission High Gears (2E) & (45E) sit over the Double Needle Roller Bearings (2T) & (45T) which sit on Synchronizing Sleeves (2C) & (45C) respectively. The Transmission Low gears (2H) & (45H) sit over the Double Needle Roller Bearings (2D) & (45D)on top of Collar Bush (2G) & (45G) respectively. Thus the Transmission High Gears (2E) & (45E) and the Transmission Low gears (2H) & (45H) free wheel on the double needle roller bearings (2D), (2T), (45D) and (45T) unless they are engaged. The Gear Changers (2K) & (45K) sit on top of Synchronizing Sleeves (2C) & (45C) respectively and it has Synchronizing Cones (2S)/(45S) and (2F)/(45F) on its either side which move with it. At this stage no


power is transmitted to cluster of gears (output) and the differential assembly (42) as no gear is engaged. Thus vehicle remains stationary-
Whenever a gear is selected by moving gear shifter lever (20A)which is the part of the Gear Shifter Assembly (20) the Cluster of Gears (output) and the Differential assembly(42) gets the power from the chain of gear drives Forward Cluster of Gears (input) assembly (2) and Reverse Cluster of Gears (input) Assembly (45).
When we select the forward first gear from the Gear Shifter lever (20A). in pin and groove type locking arrangement (L2) the Gear Shifter Bar Right Hand (22) shifts in forward direction, the ball (23C) comes out of groove (22D) (ref figure 6B & 7B) and in Ball and Spring type locking arrangement (LI) the ball(23A) shifts to backward groove (22C) (Ref figure 6B & 7B ). These two movements occur simultaneously. Both these positioning create heavy resistance to movement of the fork and so the double locking takes place. The Gear Shifter Fork Right Hand (37) is bolted to Gear Shifter Bar Right Hand (22). The Gear Shifter Fork Right Hand (37) sits over Gear Changer (2K). When Gear Shifter bar Right Hand (22) moves along with Gear Shifter Fork Right Hand (37), it shifts the Gear Changer (2K) towards Transmission Low Gear (2H) through Synchronizing Cones (2S). The taper male surface in Synchronizing Cone (2S) first engages with the taper female surface in Transmission Low Gear (2H). This causes a slow and gradually increasing of contact between the moving Synchronizing Cone (2S) and stationary Transmission Low Gear (2H). So the Transmission Low Gear (2H) slowly begins to pick up power and motion due to the gradually increasing frictional contact between Synchronizing Cone (2S) and

Transmission Low Gear (2H) till the speed of rotation of Transmission Low Gear (2H) becomes same as the speed of rotation of Synchronizing Cone (2S). Then the internal synchro gear in Gear changer (2K) meshes smoothly with the external synchro gear (not the main gear teeth) of Transmission Low Gear (2H) and at this stage full power can be transmitted from Transmission Intermediate Gears (2P) to Transmission Intermediate Shafts (2A) through Synchronizing Sleeves (2C) & Gear Changer (2K). This Transmission Low Gear (2H) is always meshed with Transmission Dual Gear (42L). This way the power is transferred to the cluster of gears (output) and the differential assembly (42), which drives the vehicle.
When we select the second gear by the Gear Shifter Assembly (20), in pin and groove type locking arrangement (L2) the Gear Shifter Bar Right Hand (22) shifts in backward direction the ball (23C) comes out of groove (22D) (ref figure 6C & 7C) and in Ball and Spring type locking arrangement (LI) the ball (23A) shifts to forward groove (22A) (Ref figure 6C & 7C). Both these positioning create heavy resistance to movement of the fork and so the double locking takes place. The Gear Shifter Fork Right Hand (37) is bolted to Gear Shifter Bar Right Hand (22). The Gear Shifter Fork Right Hand (37) sits over Gear Changer (2K). When Gear Shifter bar Right Hand (22) moves along with Gear Shifter Fork Right Hand (37), it shifts the Gear Changer (2K) towards Transmission High Gear (2E) through Synchronizing Cones (2F). This Transmission High Gear (2E) is always meshed with Transmission Dual Gear (42L). The transmission of power from Transmission Intermediate Gear (2P) to Transmission Dual Gear (42L) takes place in exactly the same way through synchronizing arrangement as described earlier. This way the power is transferred to


the cluster of gears (output) and the differential assembly (42), which drives the vehicle.
For reverses lst & 2ncf Gear working is same as described above only the changes are
1. In the Pin and groove type locking arrangement (L2) & Ball and spring type
locking arrangement (LI), Gear Shifter Bar Left Hand (21) moves and Gear Shifter
Bar Right Hand (22) remains locked in neutral location.
2. The power is transmitted through the cluster of gears (input) (45). As the cluster of
gears (input) (2) and (45) are identical the procedure of the gear shifting and power
transmission remains similar to that described above.

H.W.Kane Applicant's Agent
To
The Controller of Patents Mumbai Branch Mumbai-400037