Machine element or mechanism – Alternate manual or power operators
Reexamination Certificate
1999-05-21
2001-05-15
Estremsky, Sherry (Department: 3681)
Machine element or mechanism
Alternate manual or power operators
C180S206500, C180S220000
Reexamination Certificate
active
06230586
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electric drive device for a bicycle, and the device comprising a first unidirectional means connected between a rotatable tube and a drive gear, and a second unidirectional means connected between the rotatable tube and a crank axle in the rotatable tube.
BACKGROUND OF THE INVENTION
A conventional electric bicycle uses a motor to drive the sprocket mounted to the crank axle and a chain connected between the sprocket and the rear wheel sprocket so that when the sprocket is rotated by the motor, the rear sprocket is rotated by the chain and the bicycle moves forward. Although the motor provides the mechanical force to assist the rider to power the bicycle, the rider's feet on the pedals of the crank have to rotate with the rotation of the crank. This is inconvenient for some older riders, and when the rotational speed of the crank is raised, the rider will feel uncomfortable and unsafe because they feel that the bicycle cannot be well controlled by them. Furthermore, the rider's feet rotating with the crank makes the rider feel tired within a short period of time of operation.
The present invention intends to provide an electric drive device for a bicycle wherein the crank will not rotate with the rotatable tube when the bicycle is powered by the motor so that the shortcoming mentioned above can be resolved.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, an electric drive device for a bicycle comprises a motor having a drive shaft with a first gear mounted to the shaft. A speed reduction device has an output shaft with a second gear mounted to the output shaft. The second gear is engaged with the first gear. A bevel gear is connected to the distal end of the output shaft and engaged with an annular gear.
A rotatable tube extends through the bottom bracket of the bicycle and a crank axle rotatably extends through the rotatable tube. The annular gear is mounted to the rotatable tube, and a first unidirectional means is connected between the rotatable tube and the annular gear. The annular gear is engaged with the bevel gear and has a plurality of notches defined in the inside thereof.
The first unidirectional means has a socket and a plurality of pawls pivotally connected to the outside of the socket. The pawls are disengagably engaged with the notches when the motor is actuated to rotate the rotatable tube.
A second unidirectional means is connected between the crank axle and the rotatable tube so that when the rotatable tube is rotated by the first unidirectional means, the crank axle is disengaged with the rotatable tube by the second unidirectional means.
The main object of the present invention is to provide an electric drive device for a bicycle wherein the device occupies a limited space so that the configuration of the bicycle frame changes very few.
Another object of the present invention is to provide an electric drive device for a bicycle wherein the rider's feet need not rotate with the crank when the bicycle is powered by the motor.
Further objects, advantages, and features of the present invention will become apparent from the following detailed description with appropriate reference to the accompanying drawings.
REFERENCES:
patent: 5570752 (1996-11-01), Takata
patent: 5829546 (1998-11-01), Tseng
patent: 5845727 (1998-12-01), Miyazawa et al.
patent: 5901807 (1999-05-01), Tseng
patent: 5937964 (1999-08-01), Mayer et al.
patent: 0-907379 (1999-04-01), None
Estremsky Sherry
Gardere Wynne & Sewell LLP
Lewis Tisha D.
Warren, Jr. Sanford E.
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