192 clutches and power-stop control – Clutches – Operators
Reexamination Certificate
1999-10-15
2001-05-08
Marmor, Charles A (Department: 3681)
192 clutches and power-stop control
Clutches
Operators
C192S085060, C192S090000
Reexamination Certificate
active
06227342
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates generally to motorcycles, and more particularly to a motorcycle clutch system.
2. Description of Related Art
An existing motorcycle clutch system includes a clutch lever located at the handlebar and means for mechanically coupling movement of the clutch lever to the clutch assembly located at the engine. It does so with a clutch cable that spans the distance between the clutch lever and the clutch assembly. The clutch cable is of known design, having an inner wire disposed coaxially within a tubular flexible outer casing so that the inner wire can move axially within the outer casing to mechanically couple movement of the clutch lever to the clutch assembly.
Pulling the clutch lever toward the handlebar pulls the inner wire of the clutch cable away from the clutch assembly to thereby disengage the clutch. Releasing the clutch lever allows the inner wire of the clutch cable to move back toward the clutch assembly to thereby allow the spring-biased clutch to re-engage.
Motorcycle racing enthusiasts and other owners know that various drawbacks accompany the clutch cable design. For one thing, the clutch cable causes parasitic drag. In addition, it degrades and must be replaced. Furthermore, it requires frequent readjustment to compensate for swelling of the clutch plates and for wear. Thus, motorcycle racing enthusiast and other owners and manufacturers seek some way to address those concerns.
SUMMARY OF THE INVENTION
This invention addresses the concerns outlined above by providing a hydraulic motorcycle clutch system that can be retrofitted to an existing motorcycle originally manufactured with a clutch cable. The retrofit hydraulic clutch system includes (i) a handlebar mountable clutch lever assembly with a master hydraulic cylinder, (ii) a slave hydraulic cylinder assembly adapted to be mounted on the engine and attached to the clutch assembly, and (iii) a hydraulic line adapted to span the distance between the master and slave hydraulic cylinders in order to maintain them in fluid communication.
Thus, the invention alleviates many concerns associated with clutch cables by providing a hydraulic clutch system that is suitable in its broader aspects for retrofitting to many existing motorcycles. It causes less parasitic drag. It is less prone to degrade. It is easier and more sensitive to operate. It allows clutch lever positioning, immediate clutch response, and unchanged clutch lever feel as the clutch gets hot. It eliminates frequent readjustment to compensate for swelling of the clutch plates and for wear. It actually self adjusts.
To paraphrase some of the more precise language subsequently presented in the claims, a motorcycle clutch assembly constructed according to the invention for a motorcycle having a handlebar, a clutch lever, a clutch cable, an engine, and a clutch, includes (i) a master hydraulic cylinder assembly, (ii) a slave hydraulic cylinder assembly, and (iii) a hydraulic line adapted to communicate hydraulic fluid pressure between the two hydraulic cylinder assemblies. The master cylinder assembly is adapted to be mounted on the handlebar of the motorcycle in place of the clutch lever and it includes a integral clutch lever portion that is adapted to actuate a master cylinder portion of the assembly. The slave hydraulic cylinder assembly is adapted to be mounted on the engine of the motorcycle, to be attached to the clutch arm, and to pull on the clutch in the place of the clutch cable so that it pulls in the same general direction that the clutch cable was designed to do. The hydraulic line is adapted to communicate hydraulic fluid pressure between the master cylinder assembly and the slave hydraulic cylinder assembly so that pulling the moveable lever actuates the slave hydraulic cylinder assembly and causes it to pull on and disengage the clutch.
One embodiment takes the form of a retrofit kit that includes replacement cylinder head mounting nuts for securing a mounting bracket to the engine of a YAMAHA KF400FK1 forward of the clutch arm (or pushlever) in the place of the original clutch cable. The slave hydraulic cylinder mounting bracket supports the slave hydraulic cylinder so that it functions the same as a clutch cable from the viewpoint of the clutch assembly, in the sense that it pulls the clutch arm on the YZ400FK1 clutch assembly in the same relative direction as the clutch cable it replaces. Another embodiment retrofits on various HONDA, SUZUKI, and YAMAHA models having a clutch arm within an engine case. The slave cylinder assembly includes a piston pull rod adapted to extend through a clutch cable entranceway in the engine case so that the slave cylinder assembly bears against the case in order to thereby retain it in place without additional mounting hardware. The following illustrative drawings and detailed description make the foregoing and other objects, features, and advantages of the invention more apparent.
REFERENCES:
patent: 3899057 (1975-08-01), Carre
patent: 3935930 (1976-02-01), Kine
patent: 4560049 (1985-12-01), Uchibaba et al.
patent: 4566577 (1986-01-01), Tsuboi
Mangura HS-22 Classic Hydra Stop Brake, Bike Pro Catalog, 1996, p. 63.
Armbruster Frederick K.
Neal, III William A.
Hanson Loyal McKinley
Marmor Charles A
Rodriguez Saul
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