GB730256A - Improvements in safety devices in rope lifting or hoisting gear - Google Patents

Abstract

730,256. Balancing-devices; guided skip hoists; safety catch gear. JENKINS & CO., Ltd. W. J. Jan. 8, 1954 [June 17, 1953], No. 16659/53. Classes 78 (2) and 78 (3). Catch gear for a skip hoist counterweight which is supported in a loop of the hoisting rope 3, comprises a mechanism which, on breakage of this rope, locks the counterweight thereto by means of a progressively increasing gripping action. A disc 23 secured to a frame 18 on the counterweight has pairs of arms 26 eccentrically pivoted thereon at 24, and on each pair of arms is a fixed jaw 27 and a movable jaw 28 secured to a rod 29 the end of which is normally located in a notch 31 in the disc. The rods 29 are also connected through pins and slots 33, 34 and links 36 with rods 37 which are secured to the pulley axle 21 and are normally urged upwardly by the tension in rope 3 against the action of springs 38. In the event of rope, 3 breaking the springs 38 cause the axle to drop in slots 22 so that, through rods 37 and links 36, the jaws. 28 are moved into light engagement with the rope 3 and the rods 29 are disengaged from notches 31. This effects initial deceleration of the counterweight whereafter the arms 26 pivot and, due to the cam action of the disc 23 on the rods 29, the grip is progressively increased until the counterweight is brought to rest. Downward movement of rods 37 also operates a switch 42 which then de-energizes the hoisting motor 50. The jaws 28 are serrated and the jaws 27 are provided with helical grooves. The invention is stated to be applicable to multi-rope systems. The counterweight is in three parts 11, 12, 13 connected together for lost motion by rods 14, 16. The catch gear is prevented from operating due to slackness in the cable when the counterweight is fully lowered and telescoped, by rods 44, secured to the part 13, which hold the axle 21 at the tops of slots 22.