GB1214031A - Improvements in or relating to safety catch means for rotatable handles - Google Patents

Abstract

1,214,031. One-way-acting detents. C. J. R. FYSON & SON Ltd. 7 Jan., 1969 [1 Feb., 1968], No. 5235/68. Heading F2E. [Also in Division B8] A rotatable handle and safety catch mechanism comprises a shaft 4 journalled for rotation in a supporting structure, a radial handle 10 on the shaft, a handgrip 12 rotatably mounted on a rod 11 fixed to the radial handle, a stop means 7 secured on the supporting structure, a detent 17 movably mounted on the radial handle 10 and positioned for releasable engagement with the stop means, and linkage 14, 13 coupling the detent to the handgrip so that force exerted on the handgrip tending to rotate it in one direction causes the detent to be urged into engagement with the stop means, and force exerted on the handgrip in the reverse direction causes the detent to be urged out of engagement with the stop means. As shown, the invention is applied to a handoperated rope winch for raising or lowering a conveyer run 1, Fig. 1, of a motorized belt conveyer C, relative to wheels 2. When the handgrip 12 is grasped to rotate the radial handle 10 in the clockwise direction, Fig. 4, to raise the conveyer, the handgrip 12 itself tends to be rotated in the counterclockwise direction, so the tie rod 14 linked to it forces downwards the pawl 17 (assisted by a spring 21) into engagement with the fixed ratchet 7. (The pawl 17 is pivoted at 16 to the radial handle 10). The " winding-up " action is not prevented by this engagement. When the handgrip 12 is grasped to rotate handle 10 to lower the conveyer, handgrip 12 tends to be rotated clockwise in the sense of Fig. 4, so pawl 17 is withdrawn from ratchet 7 against the force of spring 21 and the conveyer may be lowered freely. The spring 21 is an optional feature to ensure re-engagement of the pawl and ratchet whenever the handgrip is released.