GB1333763A - Limit stop assembly - Google Patents

Abstract

1333763 Positive detents; stopping at definite positions PEAK ENG CO Ltd 6 Dec 1971 [4 Dec 1970] 57654/70 Heading F2E A limit stop assembly operable to limit rotation of devices such as cranes or turrets of fighting vehicles comprises a fixed sleeve 11, an input shaft 10 rotatable in the sleeve 11, a first detent member 22 rotatable with the shaft 10, at least one (as shown four) intermediate detent members 23, 24, 25, 26 freely rotatable on the sleeve 11 and a locking member 27 which locking member 27 has a first axial position on the sleeve 11 in which it is free to rotate on the sleeve 11 and a second axial position in which it is splined on the sleeve 11 and can be engaged by the detent member 26 to thereby hold the shaft 10 against rotation. The member 27 has a stop 29 engageable by the detent member 26 in both positions. The two positions are defined by engagement of a spring loaded ball 28 with grooves in the member 27. The first detent member 22 is of plate form having a peg 30 projecting from the lower surface thereof and each detent member 23, 24, 25, has a peg 35 secured to the outer periphery to engage the peg below or in the case of detent member 26 the peg 35 is engageable with the stop 29. The locking member 27 comprises an outer easing 37 and a cap 38. The shaft 10 has a gear 18 for driving the shaft 10 through a torque limiting clutch 19 which gear 18 engages the toothed traverse ring of the turret. Thus as the turret is traversed the shaft 10 rotates and the members 22, 23, 24, 25, 26 successively pick each other up until engagement of peg 35 with locking member 27 in its second position locks the shaft 10 against further rotation. The number of detent members may be varied and the assembly is rendered inoperative by moving the locking member 27 to its first position. As shown two detent mechanisms 13, 14 act to control rotation of the shaft 10 in respective opposite directions.