GB263185A - Improvements relating to spring balancing devices - Google Patents

Abstract

263,185. Chicago Pneumatic Tool Co., (Assignees of Benedict, W. H.). Dec. 17, 1925, [Convention date]. Spring-drum apparatus for adjustable suspension. - In spring means for supporting heavy objects at any desired height having a flexible connection to a member rotated by the spring, variations in the tension of the spring are compensated as the weight is raised or lowered, so as to obtain a constant supporting force; means are also provided to lock the rotary member if the spring breaks, to lock the rotary member in any position by gravity catches, and to adjust the spring tension. The heavy object is supported by a cable 21, Figs. 2 and 3, which runs in a groove of varying diameter in a sheave 32 connected by screws 33 to a drum 13 so that the sheave may be readily changed for another one of different size. The drum is rotated by the spiral spring 15, the inner end of which is connected to a fixed spindle 11 supported by the casing 34 and by its detachable cover 22, the cover having a slot for the cable 21. A supporting lug 8 is provided on the casing. The interior of the casing is formed with a number of ratchet teeth which are engaged, in the event of breakage of the spring, by the spring attachment pin 18 or by a pin 35, which is normally held clear of the teeth by a light spring 37, as shown in full lines, but may be forced outwardly, as shown by dotted lines, by the expansion of the broken spring 15. The hub of the drum 13 is formed with radial holes 38, Figs. 2 and 4, containing balls 39, the uppermost of which may engage the uppermost of the one way teeth 40 on the fixed spindle 11 if the speed of the drum is' low. The balls fly outwards when the drum rotates quickly and they may also be retained clear of the teeth 40 by pins 42 the ends of which engage a circular groove 44 in the hub of the drum. The weight may thus be raised at any speed and may be lowered quickly, but is locked and retained in position if lowered slowly for a short distance. The spindle 11 is formed with a square end 12, Figs. 2 and 5, with holes 27 for a locking pin 26 and with a retaining pawl 29 so that it may be held in any position to which it may be adjusted to vary the tension of the spring 15.