EASY CLUTCH MECHANISM

FIELD OF THE INVENTION

[0001] The present subject matter is related, in general to a clutch, and in particular, but not exclusively to an easy clutch mechanism for aiding the effort in actuating a clutch in a two and three wheeled vehicle with a four stroke internal combustion engine.

BACKGROUND OF THE INVENTION

[0002] A motor vehicle typically includes an internal combustion engine which imparts power to a transmission for driving the vehicle. The transmission has several gear ratios which an operator of the vehicle may put to use depending on the driving conditions. A clutch typically provides a mechanical coupling between the engine and transmission, and aids transfer of power and torque from the engine to the transmission by helping in shifting among various gear ratios. It coordinates smooth engagement of the spinning engine to the non-spinning transmission by controlling the slippage between them and hence allows the vehicle to stop without killing the engine.

[0003] The clutch can either be in engaged position or in disengaged position. When the clutch is engaged i.e. connected to a crankshaft of the engine, the transmission transfers a driving torque from the engine crankshaft to one or more wheels of the vehicle. When the clutch is disengaged i.e. disconnected to the crankshaft, the transmission is decoupled from the engine and does not transfer the driving torque to the wheel(s).

[0004] Conventional clutches include a friction type clutch that is normally held in engaged position by a clutch spring. The clutch is actuated through a manually operated clutch operating lever, usually operated by left hand thereof. The clutch operating lever is pivotally mounted to a handle bar of the vehicle adjacent to a hand grip on the handle bar and is connected to clutch by means of a clutch cable. The manual operation requires an operator to grip the clutch lever and pull it back towards him. The pullback operation actuates the clutch to the disengaged position. After selecting a desired gear ratio, the operator releases his grip upon the clutch lever and the clutch gets engaged again. This manual operation provides a sense of controlling the operation of the vehicle to the operator and hence forms a necessary part of a majority of vehicles.

[0005] In developing countries, motor vehicles specially two and three wheeled vehicles are a significant mode of public transportation in rural and urban areas. The clutch operating lever in these vehicles is put to heavy use owing to various road as well as traffic conditions. If the vehicle stops at a traffic signal, the operator may shift the transmission into neutral and leave the clutch disengaged. But this is hardly practiced. Usually the operator keeps the clutch disengaged by keeping the clutch operating lever retracted so that he may shift the vehicle to a suitable gear as soon as the traffic signal turns green to enjoy a swift acceleration from a stop condition. However the continuous retraction of the clutch operating lever corresponds to a continuous manually applied force. Repetitive retraction and release of clutch lever to disengage and engage the clutch leads to severe hand fatigue to the operator. More such actions subsequently result in an uncomfortable, painful and tiresome riding experience.

[0006] To reduce the operator fatigue, an ergonomic clutch actuator has been previously proposed in the U.S Patent No. 7,150,348 to reduce the manual force necessary to operate the clutch operating lever. It discloses a clutch actuator assembly having a clutch actuator mechanism driven by the clutch cable so that when the cable is drawn, the clutch actuator mechanism biases the clutch shaft and disenaages the clutch and when the cable is released, the clutch shaft returns to engaged position. The input force by the operator first increases and subsequently decreases as the clutch is disengaged. However this mechanism is housed inside to the crankcase thereby consuming unnecessary space in the-engine and is complex.

[0007] A need therefore exist for a simple, operator friendly mechanism that assists the force required to be applied by the operator upon the clutch operating lever and which can be easily mounted on the vehicle.

[0008] The present invention is directed to overcoming all or any of the problems as set forth above and obviate the lacunae in the prior art. Hence it is one of the objects of the present subject matter to provide a novel and improved clutch mechanism that assists and thereby reduces the manual clutch operating force by the vehicle operator and can be used by him effortlessly and conveniently.

[0009] Another object of the present invention is to provide an easy clutch mechanism that can be mounted with the present clutch system without major modifications in the vehicle configuration.

[00010] Yet another object of the present invention is to disclose an easy clutch mechanism where the input manual force applied for actuating the clutch is assisted thereby reducing the operator fatigue during long drives and providing better driving comfort.

SUMMARY OF THE INVENTION

[00011] To this end, the present subject matter discloses a retractable easy clutch mechanism comprising: a clutch assisting means; a rotatable cam lever mechanically connected to a clutch operating means, the cam lever supported by a clutch release arm and in contact with the clutch assisting means; and a holding means for supporting the clutch assisting means; wherein the said easy clutch mechanism is operable through the clutch operating means pivotally mounted on a handle bar of the said vehicle and connected to the clutch release arm, and wherein further the easy clutch mechanism assists the clutch operating force applied manually by an operator of the vehicle to operate a clutch.

[00012] According to an aspect of the present subject matter, the clutch assisting means provided in the easy clutch mechanism comprises of a spring contained in a spring housing, an actuating lever, a pivot shaft, a roller and a pin and the clutch assisting means is in direct contact with the cam lever through the roller.

[00013] According to another aspect of the present subject matter, the clutch operating means is provided with a free play zone and the clutch assisting means is operable after the free play zone is overcome.

[00014] According to yet another aspect of the present subject matter, the components of the easy clutch mechanism are held outside of and supported on a crankcase of the vehicle.

[00015] Further, the present subject matter also relates to an easy clutch mechanism supported outside of a crankcase of a vehicle, the easy clutch mechanism comprising: a clutch operating lever for manually operating a clutch; a clutch cable mechanically connecting the clutch operating lever to a clutch release arm; an adjustable cam lever pivotable at one end about a clutch rod and supported by the clutch release arm; a clutch assisting means comprising of an actuating lever rotatable about a pivot shaft, a spring contained in a spring housing, a roller in contact with the cam lever and a pin; and a holding bracket supporting the clutch assisting means; wherein when a manual force is applied on the clutch operating lever by an operator, the clutch cable is pulled and rotates the said clutch release arm which in turn rotates the cam lever through the clutch rod, and after a free play zone provided therein is overcome, the roller applies additional torque on the clutch rod through the cam lever in the direction of the clutch cable pull thereby assisting the manual force applied by the operator; and when the clutch operating lever is released by the operator, the cam lever reverts to its original position due to preload on the clutch release arm through a clutch spring.

[00016] The foregoing objectives and summary provide only a brief introduction to the present subject matter. To fully appreciate these and other objects of the present subject matter as well as the subject matter itself, all of which will become apparent to those skilled in the art, the ensuing detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. The summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in limiting the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[00017] The above and other features, aspects, and advantages of the present subject matter will be better understood with regard to the following description, appended claims and accompanying drawings where:

Figure 1 shows a perspective view of a vehicle, particularly a typical three wheeled vehicle.

Figure 2 shows a front view of the three wheeled vehicle with coverings and side panels removed.

Figure 3 shows a rear view of the three wheeled vehicle showing an internal combustion engine mounted at a posterior portion of the vehicle.

Figure 4 shows a perspective view of an easy clutch mechanism, according to an implementation of the present subject matter.

Figure 5 depicts a detailed view of the easy clutch mechanism, according to an implementation of the present subject matter.

Figure 6 shows a top view of the easy clutch mechanism mounted on a crankcase, according to an implementation of the present subject matter.

Figure 7 shows a side view of the easy clutch mechanism, according to an implementation of the present subject matter.

Figure 8 shows a sectional view of a clutch assisting means provided in the easy clutch mechanism along A-A axis.

Figure 9 shows a perspective rear view of the clutch assisting means provided in the easy clutch mechanism.

Figure 10 shows a perspective front view of the clutch assisting means provided in the easy clutch mechanism.

Figure 11 shows a detailed view of the clutch assisting means provided in the easy clutch mechanism.

Figure 12 presents a clutch operating torque graph comparing the presence and absence of the easy clutch mechanism in the clutch operation.

[00018] In the figures, the same reference numerals are given to members and parts performing the same functions.

DETAILED DESCRIPTION OF THE INVENTION

[00019] The subject matter described herein relates to an easy clutch mechanism for a vehicle. Various other features and embodiments of the mechanism according to the present subject matter will be discernible from the following further description thereof, set out hereunder. In the ensuing exemplary embodiments, the vehicle is a three wheeled vehicle generally used as a passenger carrier. However it is contemplated that the concepts of the present invention may be applied to other types of vehicles within the spirit and scope of this invention including a motorcycle. It is to be noted that the detailed explanation of the constitution of parts other than the subject matter which constitutes an essential part has been omitted at suitable places.

[00020] Figure 1 describes a side view of a typical three wheeled vehicle, referenced by the numeral 100, driven by an internal combustion engine. It is commonly used as a passenger carrier. It has a front panel 101 along with a windscreen 102. The lower portion of the front panel is connected to a front wheel 104 with a wheel cover 103 stationed in between. A handle bar assembly 109 is present behind the front panel 101 which is used to operate the said three wheeled vehicle 100. The vehicle is laterally divided into two halves, along the line X-X, the first half having the driver's seat 107 while the second half has a long passenger seat 108 with a seating capacity of minimum three passengers. The rear panel 106 along with the second half of the vehicle containing the passenger seat 108 is supported on a pair of rear wheels 105 located on either side of the longitudinal axis of the vehicle 100. In this view, a steering tube assembly is not visible to an onlooker of the vehicle. Below the passenger seat, an internal combustion engine 300 is located used to power the vehicle.

[00021] Figure 2 illustrates the front view of the three wheeled vehicle with the side panels, coverings and styling parts removed. The said three wheeled vehicle 100 is supported on a frame structure spanning from the first half to the second half of the vehicle. A front fork steering column assembly is connected to the front wheel 104 and comprises a steering column assembly, front suspension 203 and a trailing arm 204. The steering column assembly comprises of a steering column tube 202, rotatably supporting the front wheel 104 and acting as a mechanical link between a handle bar 109 and the front wheel 104. The steering column tube 202 is engulfed by a head pipe 205 on all sides and welded or secured to the head pipe. The head pipe usually houses bearings that allow the steering tube to turn freely. A clutch operating means is pivotally mounted at a distal end of the handle bar 109 preferably on the left side thereof, such that the user may grip the handle bar and concurrently operate the easy clutch mechanism by retracting and releasing the clutch operating means. According to an aspect of the present subject matter, the clutch operating means includes a clutch operating lever 410.

[00022] Figure 3 shows the rear view of the three wheeled vehicle 100 with the rear panel removed and hence showing the otherwise invisible internal combustion engine 300 mounted on a posterior portion of the vehicle frame below the passenger seat 108. The internal combustion engine 300 produces the necessary power which is then transferred to the transmission through a clutch (not shown). The engine 300 is covered with a crankcase 301 at the rear which forms an outer surface of the engine. The engine power is transferred to the wheels through a clutch. Since the basic construction of a clutch is known to those versed in the art, the details have been omitted.

[00023] Figure 4 illustrates an easy clutch mechanism which comprises of a clutch assisting means 420, a rotatable cam lever 430 and a holding means 440 for supporting the said clutch assisting means 420. The easy clutch mechanism is held outside of the crankcase 301 of the vehicle 100.

[00024] Figure 5 depicts a detailed view of the easy clutch mechanism, according to an implementation of the present subject matter. The easy clutch mechanism is operational through the clutch operating means 410 which is connected to a clutch release arm 401 through a clutch cable (not shown). In the original position of the clutch release arm 401, the clutch is engaged. After the temporary disengagement of the clutch, the clutch release arm 401 is retractable to its original position through a clutch spring (not shown) located inside to the crankcase 301. The cam lever 430 is mechanically connected to the clutch operating means 410 through the clutch release arm 401. One end of the cam lever 430 and one end of the clutch release arm 401 is pivotable about a clutch rod 403 preloaded through a clutch release spring 402. The other end of the cam lever 430 is in direct contact with the clutch assisting means 420 whereas the other end of the clutch release arm 401 supports the cam lever 430.

[00025] An adjusting provision 431 is provided in the cam lever 430 through which the position of the cam lever 430 vis-a-vis the clutch assisting means 420 can be adjusted. One end of the clutch release arm 401 supports the cam lever 430 through a bolt 432 and a washer 434 traversing through the adjusting provision 431. Therefore the adjusting provision 431 helps the clutch release arm 401 in supporting and adjusting the cam lever 430.

[00026] The clutch assisting means is now described mainly through the Figures 7-11. Figure 7 shows a side view of the easy clutch mechanism with the clutch assisting means 420. A sectional view of the clutch assisting means along the A-A axis is illustrated in Figure 8. The clutch assisting means 420 comprises a spring 421 contained in a spring housing 422, an actuating lever 423, a pivot shaft 424, a roller 425 and a pin 426. According to a preferred embodiment of the present subject matter, the spring 421 includes a torsion spring. The actuating lever 423 is pivotable about the pivot shaft 424 while the pin 426 holds the roller 425. The clutch assisting means 420 remains in direct contact with the cam lever 430 through the roller 425. The roller 425 is capable to move around the cam lever profile 433.

[00027] Further, the clutch assisting means is supported on the crankcase 301 through the holding means. According to an aspect of the present invention, the holding means includes a holding bracket 440. As shown in Figure 10, the holding means 440 comprises of a plurality of crankcase mounting provisions 441, 443 through which the holding means is held onto the crankcase 301. The actuating lever 423 is held through an actuating lever bracket 445 which is further connected to the holding bracket 440. The holding bracket 440 also includes a stopper 442 shown in Figure 11 for holding the cam lever 430 in its original position due to which the movement of the cam lever 430 towards the holding bracket 440 is restricted.

[00028] According to an aspect of the present invention, a free play is provided in the easy clutch mechanism. The cam lever 430 is marked with an initial setting mark after adjusting the free play of clutch lever at handle bar. In a preferred embodiment, the cam lever top surface is marked with 0 to 5 degrees in decreasing order. The clutch operating means and hence the cam lever is initially set at 5 degrees. The cam lever profile 433 is such that it does not change when the cam lever 430 rotation is within 5 degrees. No additional torque assists the manual force applied by the operator on the clutch operating means 410 in this zone. However after 5 degrees of free play zone is overcome, the clutch assisting means 420 starts assisting the torque required at the clutch rod 403. This assistance is carried out through the roller 425 which rolls along the cam lever profile 433 and the clutch assisting means 420 start pulling the cam lever 430 in the direction of clutch cable pull when the roller reaches 0 degrees.

[00029] The working of the easy clutch mechanism is now explained. When the clutch operating lever 410 is operated at the handle bar, the clutch cable pulls the clutch release arm 401 which rotates and cause a rotation of cam lever 430. Till the cam lever rotation is within 5 degrees, no assistance is provided to force applied by the vehicle operator i.e. no additional torque is applied at the clutch rod 403 in this region. However after the free play zone is overcome and the operator further pulls the clutch operating lever 410, the actuating lever 423 of the clutch assisting means 420 applies additional torque over the clutch rod 403 with the help of the roller 425 rolling over the cam lever profile 433 due to the preload of the spring 421. The clutch assisting means 420 thus provides additional torque in the direction of the clutch cable pull which helps to reduce the effort applied by the operator. Further the easy clutch mechanism is retractable. When the clutch operating lever 410 is released by the operator, the cam lever 420 reverts to its original position due to preload of the clutch spring. The free play zone will not be affected by the preload of torsional spring.

[00030] Figure 12 provides a graph where the torque at clutch rod (clutch operating torque) is measured alongside the clutch release arm rotation angle. The torque acting on the clutch rod was calculated at different clutch release arm angles. This torque is an indicator of the force that needs to be applied on the clutch operating means. The graph shows that the torque at the clutch release arm is less with the easy clutch mechanism after the clutch arm rotates 5 degrees compared to that without the easy clutch mechanism. Thus the effort by the operator on the clutch operating means is assisted and reduced and hence leads to better operator comfort. While the total force required to disengage the clutch remains same, the assisting force generated aids the manual force applied by the operator due to which the operator has to apply lower force after the free play zone is overcome.

[00031] The present subject matter and its equivalent thereof offer many advantages, including those which have been described henceforth. The easy clutch mechanism reduces the clutch operating force manually applied by the vehicle operator to actuate the clutch. The mechanism provides a free play zone due to which the easy clutch mechanism is actuated only after a certain degree of rotation of the clutch operating means. The roller and cam lever mechanism involves less frictional forces to operate the clutch. The mounting of the easy clutch mechanism outside of the crankcase causes easy installation with no space consumption inside the engine. Further the easy clutch mechanism reduces the operator fatigue particularly during long distance travel and allows him to effortlessly manoeuvre the vehicle during high traffic conditions.

[00032] According to an aspect of the present subject matter, the easy clutch mechanism as aforementioned is best suited for a motorcycle or a three wheeled vehicle.

[00033] The present subject matter is thus described. The description is not intended to be exhaustive nor is it intended to limit the invention to the precise form disclosed. It will be apparent to those skilled in the art that the disclosed embodiments may be modified in light of the above description. The embodiments described are chosen to provide an illustration of principles of the invention and its practical application to enable thereby one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore the forgoing description is to be considered exemplary, rather than limiting, and the true scope of the invention is that described in the appended claims.

We claim:

1. An easy clutch mechanism for a vehicle comprising:

a clutch assisting means,

a rotatable cam lever mechanically connected to a clutch operating means, the cam lever supported by a clutch release arm and in contact with the said clutch assisting means,

a holding means for supporting the said clutch assisting means,

wherein the said easy clutch mechanism is operable through the said clutch operating means pivotally mounted on a handle bar of the said vehicle and connected to the clutch release arm, and wherein further the said easy clutch mechanism assists the clutch operating force applied manually by an operator of the vehicle to operate a clutch.

2. The easy clutch mechanism as claimed in claim 1, in which the said clutch assisting means comprises of a spring contained in a spring housing, an actuating lever, a pivot shaft, a roller and a pin, the clutch assisting means being in direct contact with the said cam lever through the said roller.

3. The easy clutch mechanism as claimed in claim 2, wherein the said spring is a torsional spring.

4. The easy clutch mechanism as claimed in claim 1, wherein the said clutch operating means is provided with a free play zone and the said clutch assisting means is operable after the free play zone is overcome.

5. The easy clutch mechanism as claimed in claim 1 and claim 2, wherein upon the release of the said clutch operating means, the said cam lever reverts to its original position due to preload on the said clutch release arm through a clutch spring.

6. The easy clutch mechanism as claimed in claim 1, wherein the said easy clutch mechanism is held outside of and supported on a crankcase of the vehicle.

7. An easy clutch mechanism supported outside of a crankcase of a vehicle comprising a clutch operating lever for manually operating a clutch and a clutch cable mechanically connecting the said clutch operating lever to a clutch release arm, wherein the said easy clutch mechanism comprises:

an adjustable cam lever pivotable at one end about a clutch rod and supported by the said clutch release arm,

a clutch assisting means comprising of an actuating lever rotatable about a pivot shaft, a torsion spring contained in a spring housing, a roller in contact with the said cam lever and a pin, a holding bracket supporting the said clutch assisting means; wherein further when a manual force is applied on the clutch operating lever by an operator, the clutch cable is pulled and rotates the said clutch release arm which in turn rotates the said cam lever through the said clutch rod, and after a free play zone provided therein is overcome, the said roller applies additional torque on the said cam lever in the direction of the clutch cable pull; and when the clutch operating lever is released by the operator, the said cam lever reverts to its original position due to preload on the said clutch release arm through a clutch spring.

8. A vehicle comprising an easy clutch mechanism as claimed in any of the preceding claims, the vehicle including a two wheeled and a three wheeled vehicle.

9. An easy clutch mechanism substantially as herein described with reference to, and as illustrated in, the accompanying drawings.