System for controlling gear change of e.g. manual gear box of motor vehicle, has disengagement nuts prohibiting free movement of control cam, in disengagement position, for prohibiting control of backward gear ratio and action of calipers

摘要

The system has an interlocking device activating calipers (22A, 22B) of control nuts (22, 23). Disengagement nuts (42) authorize a control of backward gear ratio by enabling free movement of control cams (32, 34) in the calipers of the nuts, in a selection position. The disengagement nuts prohibit the free movement of the control cam, in the disengagement position, during the disengagement of high forwards gear ration, for prohibiting the control of the backward gear ratio and the action of the calipers.