GB1329592A - Suspension devices - Google Patents

Abstract

1329592 Hoists; spring drum apparatus BROOM & WADE Ltd 3 Nov 1971 [9 Nov 1970] 53260/70 Headings B8B and B8M A load suspending device comprises a load rope drum 14 rotatably mounted on a shaft 13 rotatably mounted in a support 10, 11, 12, a spiral spring 16 connecting the drum and shaft for urging the drum in a rope winding direction on the shaft, a releasable holding means 23 between the support and the shaft, a stop lever 30 being provided between the support and the drum to prevent unwinding rotation of the drum due to failure of the holding means 23 or spring 16. The holding means 23 comprises a helical spring having coils permitting the shaft 13 to be rotated relative to the support 10 to wind up the spiral spring 16 and wind rope 21 on to the drum but frictionally locking the spindle against opposite rotation unless the friction is released by opening the coils by spring end 27. The stop lever 30, pivoted to the support 10 and spring biased into an operative position, is normally held inoperative by an end 24 of the holding spring 23 extending through apertures in the support and the lever 30 to apply a torque to the lever in opposition to its spring bias, this torque being relaxed upon breakage of the spring 23 or spring 16 and the lever 30 is pivoted into locking engagement with stops 35 on the drum. In operation, a load placed on the rope 21 descends and winds up the spiral spring 16 until it is balanced thereby and the shaft 13 may then be wound by handle to raise the load to a desired level, the locking action of the spring 23 maintaining the load at such level.