Flange 1 (shown at the left by a dash line) is keyed to shaft 8 which rotates about fixed axis A of the machine. Cam 2 rotates freely on shaft 8 but its motion is limited by pins 3 and 4, press-fitted in flange 1 and sliding along concentric slots of cam 2. One end of spring 6 is attached to pin a of cam 2 and the other end to the base. When shaft 8 rotates counterclock- wise, flange 1 rotates cam 2 in the same direction. When the projection of cam 2 deflects follower 5 to the left about fixed axis B, the machine is switched off and the shaft 8 stops. At this time, pin a is in its lowest position, corresponding to maximum tensioning of spring 6. Then spring 6 begins to contract and turns cam 2 further counterclockwise. At this, follower 5 is swung to the right by spring 7 and the machine is switched on again.
$3104$SmC,SE$