AUTOMATIC VARIABLE SPEED TRANSMISSION

摘要

A multi-speed transmission mechanism for use on a bicycle, for example, wherein pressure on the pedal by the operator decreases or increases the diameter of the driver sprocket wheel to alter the gear ratio correspondingly. The sprocket is provided with opposed segments which are linked to both the sprocket wheel and an inner control disc. The segments move radially outwardly or inwardly in unison responsive to limited rotation of the control disc independently of rotation of the sprocket. Such rotation is foot controlled by the operator. Pressure on the foot pedal by the operator increases or decreases the working length of the bicycle sprocket chain by making the effective diameter of the sprocket smaller or larger. The position or gear ratio can be indexed by means of a synchronized stepped tooth index to control the required gear diameter and, therefore, the speed. This alters the gear ratio correspondingly. The gear ratio may be maintained without change by a locking device on the sprocket wheel in contact with the control disc.