Patent GB-952955-A (GB)
Title: Detent
IPC: E02F9/22
Filed: 1962-04-09
Abstract: 952,955. Shovelling machines; releasable fastenings. NEW YORK AIR BRAKE CO. April 9, 1962 [May 10, 1961], No. 13537/62. Headings E1F and E2A. [Also in Divisions F1 and F2] In detent mechanism particularly for two manually-operated valve plungers 18, 21, Fig. 1, controlling fluid motors 4, 5 actuating the bucket 6 of a loader, a rod 33, Fig. 2, longitudinally movable in a fixed sleeve 24 and centrally biased by a spring 19 is surrounded by detent balls 34 housed between conical surfaces on a fixed collar 25 and a spring-loaded stepped sleeve 27. When the rod 33 is moved to the right the spring 37 acts on the sleeve 27 to urge the balls 34 into a reduced diameter portion 41 of the rod. The detent can be manually overridden but is normally released when pressure fluid is applied to an inlet 43 comminicating with a groove 28 in the sleeve 27, the side walls of the groove having diameters differing by the thickness of the skirt 32 on fixed collar 25 so that the sleeve 27 is moved to the left against spring 37. The collar 25, or the skirt 32 thereof, may be made in one piece with the sleeve 24. The construction shown, however, facilitates changing the differential area on which the detent unlatching acts. The rod 33 is fixed to the valve plunger 18. The plunger 21 is coupled through a universal joint 44 to a second detent rod 33<SP>1</SP> similar to rod 33 but having two reduced-diameter portions 41<SP>1</SP>, 45. The valve plungers 18, 21 are hollow and connect conduits 12, 13, 16, 17 either to a pump 1 or to a sump 2. In order to tilt bucket 6 plunger 18 is manually moved to the right, supplying fluid to the left hand end of motor 5, and is held by the detent balls 34 while the bucket 6 is moved clockwise about its pivot 52. Groove 28 is vented to sump 2 via passage 43, conduit 48, shuttle valve 49 and conduit 51. At a predetermined position of the bucket 6a cam 53 shifts valve 49 upwards to supply pressure fluid to groove 28 and thus release the detent, whereupon plunger 18 returns to the "hold" position shown. When desired plunger 18 may be moved to the left to cause motor 5 to swing the bucket 6 counterclockwise, thereby lowering valve 49 to reconnect groove 28 to sump. In order to raise the bucket 6, plunger 21 is moved to the right, supplying fluid through conduit 16 to the lower end of motor 4, and is held by the detent balls 34<SP>1</SP> engaging portion 411. Conduit 16 is in continuous communication with inlet 43<SP>1</SP> so that when motor 4 reaches the end of its stroke and the pressure accordingly rises a relief valve 46, Fig. 2, opens and fluid flows to sump 2 through a restricted passage 47 and conduit 54. The back pressure then developed in groove 28<SP>1</SP> shifts sleeve 27<SP>1</SP> to release the detent balls 34<SP>1</SP> so that plunger 21 returns to the "hold" position shown. In order to raise the bucket plunger 21 is moved and manually held to the left, bringing the balls 34<SP>1</SP> near to, but not in, the portion 45. If desired, the plunger 21 may be moved further to the left to a "float" position, bringing detent balls 34<SP>1</SP> into portion 45, in which position the conduits 16, 17 and the pump 1 and sump 2 are interconnected.