GB292762A - Improvements in slack adjusters for air brakes - Google Patents

Abstract

292,762. Camp, W.S. de. June 7, 1927. Piston-rods.-In a slack-adjusting device for fluid-pressure-actuated brake mechanism the piston-rod is provided with a two-part core of which one part is rigidly secured to the rod and screws into the other part which is connected to the brake rigging, means being provided for turning the rod during the release stroke of the piston if a predetermined application stroke, is exceeded, thereby increasing the effective length of the core. The invention is an improvement upon those described in Specifications 250,532 and 259,077. The piston 23 is screwed on to a socket 24 which receives the tubular outer part 7 of the piston rod and one part 36 of the core, the parts 24, 7, 36 being secured together by a pin 25. The other part 33 of the core which screws into the part 36 is provided with a non- circular socket in which is fitted a correspondingly shaped rod 35 connected to the brake rigging. A ratchet wheel 28 secured by pins 29 to the part 7 of the piston rod is adapted to engage a pawl 48 pivoted at 50 on a bracket 49 fixed to the cylinder 1. A weighted arm 52<a> secured to the pawl spindle tends to bring the pawl into the inclined position shown in full lines in Fig. 10 as determined by a stop-pin 55. As long as the piston stroke is insufficient to carry the ratchet wheel 28 beyond the outer extremity of the pawl the latter remains between the same pair of teeth and there is no action on the ratchet, but if by reason of wear of the brake shoes this stroke is exceeded the pawl assumes the inclined position shown in Fig. 10, and upon the return stroke enters the next space between a pair of teeth 46 whereby the ratchet, the piston, the piston-rod 7 and the part 36 of the core are turned and the part 33 of the core, is moved outwardly. To prevent the returning spring 43 from tending to rotate the piston and piston-rod, it abuts on a collar 44 provided with a tongue (not shown) which projects into a groove in a fixed bushing 16. In a vertically arranged cylinder for lomomotives the return movement of the rod 35 is ensured by the provision of a pin passing through the forked end of the rod and fixed to a collar screwed on the end of the core 33 of the piston rod as described in Specification 259,077.