Worm 3 is integral with a sleeve and is rotated about fixed axis A by driving pulley 1 keyed to the right end of the sleeve. On the left end face of the worm sleeve is a clutch tooth which engages clutch member 5. Clutch member 5 slides along a key on shaft 9 which is the driven shaft and rotates freely in worm sleeve 3 about fixed axis B. Worm 3 meshes with worm wheel 4 which rotates about fixed axis D and is rigidly attached to cam 2 carrying cam lobe a. Lobe a periodically turns lever 6 clockwise about fixed axis C, shifting clutch member 5 to the left, out of engagement with worm sleeve 3 and tensioning spring 7. As a result, shaft 9 rotates intermittently with dwells whose length can be regulated by changing cam 2. Band brake 8 has a lined contact surface that exerts a constant pressure on a drum keyed to shaft 9, stopping the shaft rapidly when its dwell periods begin.
$2795$CmG,D$