BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is in the field of cable pulley clutch levers for any vehicles that use hand operated clutches. Specifically, these vehicles may include motorcycles and all-terrain vehicles (ATV) and the invention pertains particularly to methods and apparatus for reducing the pull force required to operate a clutch lever.

2. Discussion of the State of the Art

Clutch-operated motorcycles and all-terrain vehicles (ATM) have clutches connected to gear boxes for enabling a rider to change gears. Some models have foot operated clutches and gear selectors. Other models have cable operated clutches that use a clutch lever typically mounted on the left handlebar of a motorcycle or an ATV. Typical motorcycle and ATV clutches are friction clutches and include an outer clutch basket or housing driven by a crank shaft. An inner clutch hub fits into a clutch basket and both are connected to an input shaft of a gear box.

A clutch pack containing friction plates and disc plates stacked in alternate order fits into the hub and basket. The friction plates have teeth locking to slots in the outer basket while the steel plates there between have inner teeth that lock to grooves in the inner hub. A clutch pressure plate is installed over the clutch pack to apply pressure to the clutch pack compressing the friction and steel plates together, the pressure plate typically including four to six springs in mounting (one spring per bolt) to put equal pressure (several hundred pounds psi) against the clutch pack causing engagement of the clutch assembly by default.

A cable operated by a clutch lever on the left handlebar of the motorcycle or ATV may be used to disengage the clutch plate releasing the clutch hub from the clutch basket. The process engages a push rod actuator which is machined to act against a push rod toward the clutch assembly to push out the clutch plate against spring tension to disengage the clutch. The clutch lever when depressed disengages the clutch and when released engages the clutch.

Clutches in the current art are of a smaller diameter with a larger number of clutch friction plates and clutch steel plates so the clutch assembly is smaller in diameter but much deeper providing the frictional surface area to fully engage the clutch inner hub and outer basket as a single unit. Typically, a rider grips the lever of the handlebar and the clutch lever in a same grip movement to disengage the clutch to switch gears. The force required to grip and compress the clutch lever may be significant (varying between models) and repetitive operation of a clutch lever may cause strain and even injury to a rider. The difficulty in operating the clutch lever may be different from model to model of motorcycle and ATM due to different frictional pressure ratings of the clutch assembly and whether the assembly is assisted hydraulically or not.

Therefore, what is clearly needed is a clutch lever resistance reducing mechanism that may reduce the amount of force a motorcycle or ATM rider is required to exert when gripping and contracting the clutch lever to the handlebar grip.

BRIEF SUMMARY OF THE INVENTION

According to an embodiment of the present invention, a clutch actuation force reducing apparatus is provided including an annular housing having a bottom wall, a sidewall, and a depth, the housing open at one end, an annular cover plate having a diameter and a plate thickness, the cover plate adapted to close the open end of the housing, a pair of anchor plates having a uniform length, a uniform width, and a uniform plate thickness, one anchor plate fixed to the bottom wall of the housing, the remaining anchor plate fixed to the underside of the cover plate, the anchor plates positionally aligned upon assembly of the cover plate to the housing, a pivot plate assembly including a first pair pivot plates and a second pair of pivot plates, the pivot plates having a uniform length, a uniform width, and a uniform plate thickness, the first pair of pivot plates connected to pivot to one end of the pair of anchor plates, the first pair of pivot plates having a cable connection to a first cable routed through the sidewall of the annular housing and connected to a clutch lever, the second pair of pivot plates connected to pivot to the remaining end of the pair of anchor plates, the second pair of pivot plates having a cable connection to a second cable routed through the sidewall of the annular housing and connected to a clutch actuator in turn connected to a clutch plate of a clutch basket assembly, and a pair of idler plates having a uniform length, a uniform width, and a uniform plate thickness, the idler plates connected to the first and second pair of pivot plates at the unanchored ends of the pivot plates, the idler plates adapted to control pivot motion of the first and second pair of pivot plates. An operator may urge the clutch lever down to a handle grip to pull the first pair of pivot plates to initiate pivoting thereof about the connection at the pair of anchor plates, the pull force translated to the second pair of pivot plates over the pair of idler plates and dividing the stock pull force over the two pivot points at the pair of anchor plates to reduce the amount of physical force required at the clutch lever to actuate disengagement of an engaged clutch assembly.

In one embodiment, the pivot points at the pair of anchor plates are vertical pins extending orthogonally through the anchor plates and through first and second pair of pivot plates respectively and retaining the pivot plates in an aligned stack at respective ends, the anchor plates sandwiching the ends of the first and second pair of pivot plates. In one embodiment, the pivot points at the pair of idler plates are vertical pins extending orthogonally through the idler plates and through the first and second pair of pivot plates respectively and retaining the pivot plates in an aligned stack at respective ends, the idler plates sandwiching the ends of the first and second pair of pivot plates.

In one embodiment, the first and second pair of pivot plates exhibit a hook feature on one side, the hook feature used to retain cylindrical cable ends of the first and second cables. In the embodiment using pins, the pins are retained in the pivot plate assembly at the cable interfacing ends of the pivot plate stacks with circle clips at least at the top end of the pins. In this embodiment, the pins are retained in the plate assembly at the anchor plates by the bottom of the housing and the underside of the cover plate. In a preferred embodiment, the clutch actuation force reducing apparatus is mounted to the left handlebar of a motorcycle or of an all-terrain vehicle (ATV). In one embodiment, the cover plate is installed onto the housing with machine screws.

In the embodiment using pins, the first and second pair of pivot plates are spaced apart at the pivot points with a pair of annular spacers placed over the pins. In a variation of this embodiment, the first and second cable connections to the first and second pair of pivot plates respectively are annular rings having an outside diameter and an inside diameter and a ring thickness, the rings connected in between each pair and over the vertical pins. In one embodiment, the motorcycle is one of a Japanese model or one of an American model wherein specific components of the apparatus are modified to adapt to the Japanese model or the American model. In a variation of this embodiment, the American model is a Harley Davidson™ model, and the Japanese model is one of a Kawasaki™ model a Suzuki™ model, or a Yamaha™ model. In one embodiment, the anchor plates are fixed by welding them to the housing bottom wall and to the underside of the cover plate. In one embodiment, actuation of the clutch assembly is accomplished using a push rod to displace a clutch plate from a clutch basket.

