Driven shaft 1 rotates about fixed axis B-B. Handwheel 2 is connected by a screw pair to thread b of shaft 1. Lever 4 turns about fixed axis A and is held in constant contact with hand- wheel 2 by spring 3. The forked end of lever 4 slides along pin a of the hub of friction wheel 5 which can be shifted on feather key d along axis D. Wheel 5 engages friction disk 6 which is keyed to driving shaft 7. The required speed of shaft 1 is obtained by adjusting handwheel 2 along axis B-B, and rotation is transmitted from shaft 7 through friction disk 6, friction wheel 5 and bevel gears 8 and 9 to shaft 1.
$3421$CF,ML$