Face cam 1 has symmetrically located identical curvilinear grooves a and rotates together with the pulley assembly about fixed axis A. Cam 1 is rigidly attached to (or integral with) gear 3 and can be turned about axis A with respect to disk 2 by gear 4 which is connected by turning pair B to disk 2 and meshes with gear 3. After being turned to the required position, gear 4 is locked by means of pawl 5. The rim of the variable-diameter pulley consists of sectors c whose slotted members e carry pins b which slide along grooves a. Slotted members e slide along pins k of disk 2. When cam 1 is turned with respect to disk 2, the grooves of the cam actuate pins b, simultaneously expanding or contracting the pulley by moving sectors c either away from or toward centre A.
$3300$GrC,ML$