Pin wheel 1 rotates about fixed axis A and carries pins a which consecutively engage helical slot b of link 2. Link 2 rotates about fixed axis B which crosses axis A. When link 2 rotates continuously, pin wheel 1 rotates intermittently with dwells. The law by which the angular velocity of link 1 varies depends upon the shape of helical slot b.
$2652$PG,GW$