GB802780A - Improvements in or relating to apparatus for assembling piston rings on a piston - Google Patents

Abstract

802,780. Assembling piston-rings, GENERAL MOTORS CORPORATION. March 20, 1957 [March 21, 1956], No. 9138/57. Class 83 (4). Apparatus for assembling piston-rings on a piston comprises at least one retainer for a plurality of piston-rings, a receiver for said rings spaced from said retainer, a piston-ring carrier reciprocable between said retainer and said receiver, and a device on said carrier and movable relative thereto for spreading open said rings, said receiver and said spreader device having cooperable members adapted to effect relativemovement between said spreader and said carrier upon movement of said carrier towards said receiver so as to spread open a ring within said receiver and thereafter release said ring. The apparatus has a base-plate 12 mounted on legs 14 and carries piston-ring-retaining arbors 16 arranged in an arc about a recess 18 for receiving a piston 24. Piston-ring carriers 20 transfer the rings 22 from the arbors to the recess 18 where they are spread open to embrace the piston. Each arbor has a ring gap guide rib 26 and each ring carrier includes a guide block 38 carrying a guide plate 42 reciprocable by a piston and cylinder 60 in guideways 40 and 46 in the base-plate. Ring carriers of different heights are provided by using shim plates 48 of different thicknesses. The guide plate is retained in the guide slot 46 by retainers 50 secured by a cover-plate 52. The outer end of each guide-plate is forked to provide arcuate portions 58 for receiving a piston-ring. Secured to each guide-plate 42 and extending between the fork of each plate is a relatively movable member 66 carrying a triangular spreader 70. The recess 18 is formed in part by a member 74 circumferentially slotted at 76 to receive the piston-rings. The travel of the rings through the member 74 is limited by stops 78 and 80. movable along guides 82 and 84 respectively by hydraulic cylinders 86 and 87. Beneath the recess 18 is a device 92 for signalling the receipt of a piston and releasing the spread rings to engage in the piston-ring grooves. This device comprises a sleeve 96 rotatably mounted on the plate 12. A limit switch 100 is secured to the sleeve and a spring-loaded actuator rod 106, which normally projects above the base of the recess 18, is mounted within the sleeve and aligned for engagement with the actuator 104 of the switch 100. Also secured to the sleeve is an arcuate cam 108 having spaced peripheral recesses 110 for receiving rollers 72 carried beneath the spreader 70. A lever arm 112 on the sleeve is connected to an hydraulic cylinder (not shown). In operation, as a ring carrier moves a ring within the recess 18 the spreader roller 72 engages with a cam recess 110 and is stopped. Continued forward movement of the guide-plate moves the piston-ring forwardly relative to the spreader 70 which opens the ring. The receipt of a piston within the recess 18 depresses actuator rod 106 and operates limit switch 100 to signal rotation of cam 108 and the return of the ring carrier 20. Rotation of the cam 108 by the hydraulic cylinder 114 causes the roller 72 to ride out of the recess 110 and thereby retracts the spreader 70 to release the ring which snaps into the piston-ring groove. Immediately following the release of the piston rings the carriers are retracted through the operation of time delay relays (not shown) to a position in which a stop 120 engages a switch 122 to signal a repeat of the operation.