The mechanism is started and stopped by means of clutch 1 which engages and disengages gear 2 whose rotation is transmitted to shaft A. Keyed to shaft A is cam 3 which actuates lever 4. As lever 4 turns in either direction it depresses one of plungers 5 of pneumatic directional valve 6. Air admitted into one of the ends of cylinder 7 moves piston 8 toward the other end. At this, lever 10 shifts clutch member 9 in one or the other direction. In the left-hand position of clutch member 9, shaft A is imparted a higher speed through gears 11 and 12, and in the right-hand position, through gears 13 and 14, the speed of shaft A is lower.
$4038$THP,SR$