Reverse Gear Shift Mechanism for a Three Wheeled Vehicle

Field of Invention

[0001] The present invention relates to a reverse gear shift mechanism for a three-wheeled vehicle and more particularly to three-wheeled vehicles having handlebar operated gear shift means.

Description of Prior Art

[0002] Conventional three wheeled vehicles have handlebar-operated gear shifting means. Shifting of gears for forward motion is carried out by a known manual gear shifting arrangement provided on the left side of the handlebar. For reversing the vehicle, the user operates an external lever in addition to the gear shifting means provided on the handlebar. The external lever engages an idler gear, which provides reverse motion and the vehicle can be reversed in all gears. In such a reverse gear shift arrangement, there is high possibility that the vehicle moves in reverse direction with more speed than is intended due to selection of a higher gear by the rider, thereby leading to safety concerns. Further in this arrangement, during reverse gear operation, the rider has to lean down to actuate the external lever. This causes inconvenience and fatigue to the rider.

[0003] To overcome the abovementioned drawback, in a known prior art arrangement, an exclusive reverse gear is incorporated in the gear box. In this system, reverse gear operation is done in the same manner as forward gear operation, by way of gear shifting means provided on the handlebar. This mechanism does away the use of the additional external lever and prevents over-speeding of the vehicle while reversing. However, in this particular arrangement, there is a real possibility of the reverse gear getting engaged during forward motion of the vehicle. Such an occurrence would result in torsional failure of gears and would also cause unsafe riding conditions.

[0004] There is therefore a need for an improved reverse gear shift mechanism for three wheeled vehicles, which obviates the various defects and drawbacks in the prior art.

Summary of invention

[0005] The present invention has been conceived in view of the foregoing problems and it is the objective of the present invention to provide a reverse gear shift mechanism for a three wheeled vehicle, which prevents unintentional engagement of reverse gear during forward motion of the vehicle. It is a further objective of the present invention to provide a reverse gear shift mechanism that provides safe riding conditions and that which prevents torsional failure of gears. It is another objective of the present
invention to provide a reverse gear shift mechanism that avoids the use of an external lever for reverse gear actuation.

[0006] The reverse gear shift mechanism for a three vehicle as per the present invention comprises a reverse gear engagement means, a torque transmission means, a gear shift sector, a reverse shifting cam, a follower assembly, a reversing lever, a slider dog gear, a reverse stopper arm, a reverse drive gear, a reverse idler gear, a final drive gear and a differential hub gear. The torque transmission means further comprises a clutch, a primary gear, a primary cluster gear and a clutch gear shaft. Rotary motion of the crankshaft of the three-wheeled vehicle is transmitted by the clutch to the clutch gear shaft through the primary gear and the primary cluster gear. The gear shift sector is connected to the reverse shifting cam which in turn is connected to the follower assembly. One end of the reversing lever is rotatably mounted on the follower assembly in this manner that on actuation of the follower assembly, the other end of the reversing lever moves the slider dog gear towards the reverse drive gear. The slider dog gear is slidably mounted on the clutch gear shaft. The reverse drive gear is meshed to the reverse idler gear which in turn is meshed to the final drive gear which is further meshed to the differential hub gear. The reverse stopper arm extends between the cluster gear shaft and the final drive gear. The reverse gear
engagement means is actuated by the rider by way of a twist grip located on the handlebar of the three wheeled vehicle.

[0007] When the vehicle is stalled and the reverse gear engagement means is actuated, the end of the reverse stopper arm connected to the clutch gear shaft is lifted. This enables the slider dog gear to engage with the reverse drive gear thereby allowing transmission of rotary motion from the cluster gear shaft to the differential hub gear. The slider dog gear is moved by the reversing lever, which in turn is actuated due to the action of the reverse shifting cam. When the rider operates the reverse gear engagement means, the reverse shifting cam pushes the follower assembly resulting in actuation of the reversing lever.

[0008] The reverse stopper arm remains connected to the clutch gear shaft during forward motion of the vehicle. There is therefore no scope for the slider dog gear to engage with the reversing lever hence preventing unintentional actuation of the reverse gear mechanism when the vehicle is in forward motion. Thus there is no possibility of torsional failure of gears due to inadvertent reverse gear engagement. Further, the use of external lever for reverse gear engagement has been avoided thereby improving riding comfort.

[0009] These and other features, aspects, and advantages of the present invention will be better understood with reference to the following description, the appended claims and the accompanying drawings. This summary is not intended to limit the scope of the claimed subject matter.

Brief description of drawings

[0010] The above and other features, aspects, and advantages of the present invention are further illustrated by the accompanying drawings. The drawings are given by way of illustration only and are not limitative of the present invention. A brief description of the drawings is as follows:

Fig. 1 is a side view of a conventional three wheeled vehicle.

Fig. 2 is an isometric view of a power unit of a three wheeled vehicle.

Fig. 3 is a top view of a transmission system having a reverse gear shift mechanism as per the present invention.

Fig. 4 is an isometric view of a transmission system having a reverse gear shift mechanism as per the present invention.

Detailed description of invention

[0011] Hereinafter, a preferred embodiment of the present invention is explained in detail with reference to the drawings.

[0012] Figure 1 illustrates a side view of a conventional three-wheeled vehicle. A driver's cabin 13, which is open from both sides, enables the driver to enter and exit the vehicle. The driver's cabin 13 is provided with a driver's seat 15 and a handlebar 14. Control means for operation of clutch, gear, throttle etc. is provided on the handlebar 14. The vehicle has a front wheel 10 and two wheels 11 at the rear. The vehicle further has a passenger compartment 16 with a passenger seat 17.

[0013] Figure 2 is an isometric view of a power unit of the three wheeled vehicle. The power unit is generally mounted on the chassis 19 near the axis of the rear wheel 11. The power unit is provided with an lockable access door 18 on the vehicle. The power unit comprises an internal combustion engine 20 and a transmission system 21. Power generated by the internal combustion engine 20 is transferred through the transmission system 21 to wheels of the vehicle. The transmission system 21 is constant mesh type and has been illustrated in Figure 3 and Figure 4.

[0014] Referring to Figure 3 and Figure 4, the transmission system 21 of a three-wheeled vehicle receives rotary motion from a crankshaft (not shown in the figures) through a torque transmission means. The torque transmission means comprises a clutch 100, a cluster gear shaft 101, a primary gear 102 and a primary cluster gear 103. Rotary motion of the crankshaft is transmitted to the clutch 100, which in turn transmits it to the cluster gear shaft 101 through the primary gear 102, which is in mesh with the primary cluster gear 103. During forward motion of the vehicle, a plurality of cluster gears 104 mounted on the cluster gear shaft 101, gets engaged with a plurality of drive gears 105 as per the speed requirement. The said drive gears 105 are mounted on a drive shaft 106 and a cross (not shown in the figures) enables choosing of speed gears as per vehicle rider's requirements. The drive shaft 106 is also mounted with a final drive gear 107 that transmits torque to a differential hub gear 108. The differential hub gear 108 is connected to the differential hub, which in turn is connected to the wheel of the vehicle.

[0015] The reverse gear shift mechanism for a three-wheeled vehicle as per the present invention consists of a reverse gear engagement means, a gear shift sector 109, a reverse shifting cam 110, a follower assembly 111, a reversing lever 112, a slider dog gear 113, a reverse stopper arm 114, a reverse drive gear 115 and a reverse idler gear 116. The gear shift sector 109 is cable connected to the reverse gear engagement means. The reverse shifting cam 110 is connected to the gear shift sector 109 by way of a D-Slot through a shaft. The follower assembly 111 is connected to the reverse shifting cam 110 and has a reversing lever 112 rotatably mounted to it. The slider dog gear 113 is slidably mounted on the cluster gear shaft 101. The reverse drive gear 115 is meshed to the reverse idler gear 116 which in turn is in continuous mesh to the final drive gear 107. The reverse stopper arm 114 has its one end 114b connected to the final drive gear 107. The other end 114a of the reverse stopper arm 114 is connected to the cluster gear shaft 101 and is placed in a groove between the slider dog gear 113 and the reverse drive gear 115.

[0016] The three-wheeled vehicle is to be stalled when the rider intends to reverse it. Once the vehicle is stalled and the reverse gear engagement means is actuated, the end 114a of the reverse stopper arm 114 connected to the cluster gear shaft 101 is lifted. This lifting action is due to a counterweight 114c attached to the other end 114b of the reverse stopper arm 114. The lifting of the end 114a of the reverse stopper arm 114 enables the slider dog gear 113 to engage with the reverse drive gear 115. The slider dog gear 113 is moved towards the reverse drive gear 115 due to the action of the gear shift sector 109, the reversing shifting cam 110, the follower assembly 111 and the reversing lever 112. On actuation of the reverse gear engagement means, the gear shift sector 109 rotates which in turn rotates the reverse shifting cam 110. When the reverse shifting cam rotates, a protrusion 110a on it pushes the follower assembly 111 inward. When the follower assembly 111 is moved, the reversing lever 112 is actuated. The reversing lever 112 drives the slider dog gear 113 to engage with the reverse drive gear 115. This mechanism and the mesh arrangement of the reverse drive gear 115, the reverse idler gear 116, the final drive gear 107 and the differential hub gear 108 transmits rotary motion of the cluster gear shaft 101 to the wheels of the vehicle and in this manner the vehicle is reversed. The reverse drive gear 115 is designed for one fixed axial position and need not be engaged or disengaged for transmitting motion. The slider dog gear 113 carries out this function.

[0017] The reverse gear engagement means is operated by the rider by means of a twist grip located on a handlebar of the three wheeled vehicle.

There is a spring arrangement 111a provided on the follower assembly 111 to bring it back into contact with the reverse shifting cam 110 after reverse gear operation. During reverse gear operation, the cross is moved to an isolated position so that it is not engageable with any of the speed gears (cluster
gears 104 and drive gears 105) used for forward motion. The vehicle therefore moves in the reverse direction within a specific safe speed limit.

Further, the reverse stopper arm 114 remains connected to the cluster gear shaft 101 during forward motion of the vehicle. The reverse stopper arm 114 remains connected due to rotary motion of the final drive gear when the vehicle is moving forward. Hence unintentional actuation of reverse gear shift
mechanism during forward motion of the vehicle is prevented.

[0018] The foregoing description is a specific embodiment of the present invention and has been described for the purpose of illustration only. Persons skilled in the art may practice numerous alterations and modifications of the present invention without departing from its spirit and scope. 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.

Description of reference numerals

[0019]

10: Front wheel
11: Rear wheel
13: Driver compartment
14: Handlebar
15: Driver's seat
16: Passenger compartment
17: Passenger seat
18: Lockable access door
19: Chassis
20: Internal combustion engine
21: Transmission system
100: Clutch
101: Cluster gear shaft
102: Primary gear
103: Primary cluster gear
104: Cluster gears
105: Drive gears
106: Drive Shaft
107: Final drive gear
108: Differential hub gear
109: Gear shift sector
110: Reverse shifting cam
111a: Protrusion on the reverse shifting cam
111: Follower assembly
111a: Spring arrangement on the follower assembly
112: Reversing lever
113: Slider dog gear
114: Reverse stopper arm
114a: Reverse stopper arm end connected to the cluster gear shaft
114b: Reverse stopper arm end connected to the final drive gear
114c: Counterweight attached to reverse stopper arm
115: Reverse drive gear
116: Reverse Idler gear

We Claim:

1. A reverse gear shift mechanism for a three-wheeled vehicle comprising:

a reverse gear engagement means;

a torque transmission means further comprising a clutch 100, a primary gear 102, a primary cluster gear 103 and a clutch gear shaft 101;

a reverse drive gear 115 meshed to a reverse idler gear 116 which in turn is meshed to a final drive gear 107; a differential hub gear 108 meshed to the final drive gear 107; a reverse shifting cam 110 connected to a gear shift sector 109, such that when the reverse engagement means is actuated, the said reverse shifting cam 110 pushes a follower assembly 111; a reversing lever 112 rotatably mounted at its one end to the follower assembly 111, such that the other end of the said reversing lever 112 drives a slider dog gear 113 towards the reverse drive gear 115, when the said follower assembly 111 is actuated; and a reverse stopper arm 114 extending between the cluster gear shaft 101 and the final drive gear 107;
wherein on actuation of the reverse gear engagement means, an end 114a of the reverse stopper arm 14 its lifted, the said end 114a connected to the clutch gear shaft 101, which enables the slider dog gear 113 to engage with the reverse drive gear 115, allowing transmission of rotary motion from the clutch gear shaft 101 to the differential hub gear 108;

2. The reverse gear shift mechanism for a three-wheeled vehicle as claimed in claim 1 wherein the slider dog gear 113 is slidably mounted on the clutch gear shaft 101.

3. The reverse gear shift mechanism for a three-wheeled vehicle as claimed in claim 1 wherein rotary motion of a crankshaft is transmitted by the clutch 100 to the clutch gear shaft 101 through the primary gear 102 and the primary cluster gear 103.

4. The reverse gear shift mechanism for a three-wheeled vehicle as claimed in claim 1 wherein the reverse gear engagement means is actuated by a twist grip located on a handlebar of the three wheeled vehicle.

5. The reverse gear shift mechanism for a three-wheeled vehicle as claimed in claim 1 wherein the reverse stopper arm 114 remains connected to the clutch gear shaft 101 during forward motion of the three wheeled vehicle.

6. The reverse gear shift mechanism for a three-wheeled vehicle as claimed in claim 1, wherein the end 114a of the reverse stopper arm 114 connected to the clutch gear shaft 101 is lifted during actuation of reverse gear engagement means, due to action of a counter weight 114c secured at the other end 114b of the reverse stopper arm 114. 7. The reverse gear shift mechanism for a three-wheeled vehicle as hereinabove described in the specification and illustrated in the accompanying drawings.