Ratchet wheel 6 rotates about fixed axis A. Link 3 is connected by turning pair B to link 4, turning about axis A, and by turning pair C to nut a. Pawl 5 is connected by turning pair E to link 4 and engages wheel 6. When link 2 of four-bar linkage DCBA is oscillated by tie-rod 1, pawl 5 turns ratchet wheel 6 intermittently counterclockwise. The rate of feed (angle of rotation of ratchet wheel 6) can be varied by adjusting slider (nut) a along the slot in link 2 by means of screw b and clamping it in the required position.
$1818$LR,6L$