Pedal crank drive for a bicycle
First Claim
1. A pedal crank drive for a bicycle, comprising two pedal cranks which are non-rotatable interconnected by a pedal crank shaft, a chain sprocket, which has at least one gear ring and is mounted to be rotatable relative to the pedal crank shaft, and at least one force-transmitting spring, which is disposed between the chain sprocket and that pedal crank which is adjacent to the chain sprocket, and said spring is adapted to be biased by a forward rotation of the pedal cranks as well as a damping spring, which is prestressed in a sense to bias the force-transmitting spring, is provided between the chain sprocket and the adjacent pedal crank, characterized in that the initial stress of the damping spring is adjustable in dependence on the spring excursion of the force-transmitting spring.
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Accused Products
Abstract
In a pedal crank drive for a bicycle, comprising two pedal cranks (4a, 4b) which are non-rotatably interconnected by a pedal crank shaft (3), a chain sprocket (5), which has at least one gear ring (6) and is mounted to be rotatable relative to the pedal crank shaft (3), and at least one force-transmitting spring (10), which is disposed between the chain sprocket (5) and that pedal crank (4a) which is adjacent to the chain sprocket (5), and said spring (10) is adapted to be biased by a forward rotation of the pedal cranks (4a, 4b), it is proposed to improve the distribution of the torque during a revolution of the chain sprocket in that a damping spring (15), which is prestressed in a sense to bias the force-transmitting spring (10), is provided between the chain sprocket (5) and the adjacent pedal crank (4a).
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Citations
5 Claims
- 1. A pedal crank drive for a bicycle, comprising two pedal cranks which are non-rotatable interconnected by a pedal crank shaft, a chain sprocket, which has at least one gear ring and is mounted to be rotatable relative to the pedal crank shaft, and at least one force-transmitting spring, which is disposed between the chain sprocket and that pedal crank which is adjacent to the chain sprocket, and said spring is adapted to be biased by a forward rotation of the pedal cranks as well as a damping spring, which is prestressed in a sense to bias the force-transmitting spring, is provided between the chain sprocket and the adjacent pedal crank, characterized in that the initial stress of the damping spring is adjustable in dependence on the spring excursion of the force-transmitting spring.
Specification