GB1252985A - - Google Patents

Abstract

1,252,985. Spring-and-lever load supports. D. R. ALDRIDGE. 6 March, 1970 [11 March, 1969], No. 12619/69. Heading F2S. In a constant-force spring-and-lever support, e.g. for piping, the lever system consists of crossed toggle linkages and the spring means comprises torsion springs. In Figs. 1 and 2, a load-carrying rod 21 depends from a frame 19 which is pivotally secured by linkages 15, 17 to two levers 7 which in turn are pivotally secured to a frame 3, the latter being fixed in use. The pivotal connections between the frame 3 and levers 7 each incorporate torsion springs in the form of rods 9 which are functionally in series with tubes 11 which surround the rods and are secured to them by means of collars 13. The effective length of the levers 7 may be adjusted by varying the positions of their pivotal connections 23 to the links 15, 17 by means of screws 25. Prior to use, the lever system is forcibly collapsed from its " natural " state, with its springs unstrained (broken lines) to the full-line position shown and temporarily held in this state by a bolt 27. Once the load has been connected, the bolt is released and the apparatus has a substantially constant-force characteristic. In Fig. 3, the rod-and-tube torsion springs of Figs. 1 and 2 are replaced by bars 55 located in slots in the levers 37 (which correspond to the levers 7 of Fig. 1). Like the rods and tubes of Fig. 2, the bars 55 of Fig. 3 project in both directions beyond the levers and, at each end, they are fitted into slotted members 57, Fig. 4 (not shown) which can be slid along the bars to vary their effective length. In Figs. 5 to 7 (not shown), bars as in Figs. 3 and 4 are employed as the torsion springs, but in place of the slidable slotted members which vary the effective length of the bars, like slotted members are fixed to the bars and are arranged to be rotatable to apply a torsional pre-stress to the bars.