Speed change device with detent means

摘要

A speed change device for a bicycle comprising an upper fixed transverse support and a lower movable transverse support carrying a chain guide and movable with the lower support to derail a chain with respect to a set of pinions of graduated size on a free wheel to change the gear ratios. An articulated parallelogram linkage connects the upper and lower supports to permit transverse displacement of the lower support; a pivotal member is pivotably mounted on the upper support and is adjustably connected to the lower support and a control cable is attached to the pivotal member at a pair of locations on opposite sides of the pivot axis thereof to pivot the pivotal member under the control of the cyclist and produce transverse displacement of the lower support and the chain guide thereon. The pivotal member and the upper support carry a detent arrangement for establishing stop positions corresponding to the engagement of the chain with the respective pinions on the free wheel. The detent arrangement is constituted by a plurality of recesses in one of the members equal in number to the speed changes and a projection in the form of a spring-loaded member selectively engageable in the recesses as the pivotal member undergoes pivotal movement between speed changes.