The housing of the indexing head is fastened to the reciprocating table of the machine. Keyed to shaft 12 and turning about axis A, are forked lever 2, extending from the side of the head, and bevel gear 1. In the reciprocation of the head, lever 2, outside the housing, engages fixed pin d, secured to the machine base, and is turned through a definite angle. Bevel gear 3 is rigidly attached to arm 4 which rotates freely on shaft 13 about axis B and carries spring-loaded pawl 6. This pawl engages ratchet wheel 7 which is keyed on bevel gear 8. Locking ring 11 is keyed to ratchet wheel 7 and is engaged by spring-actuated plunger 10 in the housing. Cam 5 is pinned to arm 4. Plunger 10 is wide enough so that it contacts cam 5 and is lifted by the cam out of engagement with locking ring 11. When the head travels to the right, lever 2 is turned clockwise, gear 3, arm 4 and cam 5 are also turned clockwise. Pawl 6, engaging a tooth of ratchet wheel 7 turns it together with bevel gear 8 through the required angle. This rotation is transmitted by gearing (not shown) to worm wheel 9 and shaft 13, to the left end of which the workpiece is fastened. The shaft is held in its indexed position by plunger 10 and the workpiece is machined while the head travels to the left. Near the end of this stroke, lobe a of cam 5 lifts plunger 10 out of engagement with locking ring 11 just before pawl 6 engages the next tooth on ratchet wheel 7.
$3356$CR,FD$