GB465941A - Improved spring device - Google Patents

Abstract

465,941. Resilient mountings. GENERAL SPRING CORPORATION. Aug. 13, 1935, No. 22800. Convention date, May 9. [Class 108 (iii)] Relates to a spring support particularly for high temperature equipment such as steam pipes, oil refinery piping, &c. movable through a limited range and comprising main spring means supporting the load through a pivoted member with a variable force transmission ratio and auxiliary spring means adapted to assist or oppose the action of the main spring means to a changing extent during at least part of the movement of the load so as to obtain a supporting force which is substantially equal to that required to support the load in any position in its range of movement. According to the invention means are provided for adjusting the main spring means to increase or decrease the mean force exerted thereby within the range of movement and for adjusting the angle at which the main spring means acts upon the pivoted member. In the spring support shown in Fig. 1 the load is supported by a rod 27 secured to a yoke 26 suspended by pivoted links 35 from levers 24 pivoted at 23 on a fixed frame 22, each lever 24 being connected by main and auxiliary springs 30, 42 to a cross-member 40 of the frame, the spring 42 having a lost-motion connection with the lever 24 so that it comes into action when the yoke 26 is approximately in its mean position and is moving downwardly. The upward and downward movements of the levers 24 are limited respectively by a T-strut 28 and a shelf 25, the latter also acting to support the load should any part of the device break. In order to make the support adjustable to cover as large a range of loads as possible the lower end of the spring 30 is movable in an inclined slot 46 on the lever 24 and its position determined by a screw 47. A turnbuckle 43 or like device connects the spring 42 to its pivot 45. In a modification, Fig. 5 (not shown), the springs 42 are replaced by a tension spring extending between the pivots 45 so that as the yoke passes through its mean position the spring passes dead centre and its action is reversed. In a further modification the main springs are replaced by a single spring 30a, Fig. 4, extending between the levers 24a which are connected by the permanently-acting springs 42a to the fixed frame. In both these modifications the end connections of the main springs are adjustable by screw means such as shown in Fig. 1 or by the provision of a series of holes in each of the levers 24a, Fig.. 4, with any one of which an end of a main spring may be engaged. Fig. 3 shows a construction in which auxiliary springs 53 act partly with and partly against the main springs 30 during the whole travel of the yoke 26, while supplementary springs 63 act with the main springs only during the lower half of the travel of the yoke. The auxiliary springs 53 are fixed at their lower ends 54 to the frame and at their upper ends 52 to one arm of a bell-crank 50 pivoted at 51 to the frame and the other arm of which is pivoted at 55 to a link 56 pivotally connected at its lower end 57 to the lever 24. By means of an eye 58 constituting a lost-motion connection, the link 56 engages one arm 60 of a second, double-armed member rotatable about pivot 51 and having its other arm 61 connected by the springs 63 to the frame. In operation when the lever 24 moves downwardly from its uppermost position the springs 53, as they move in a clockwise direction towards the dead-centre position shown, tend to support the load with a decreasing moment. As the dead-centre position is past the springs 53 reverse their action tending to push down on the load but are over-balanced by the springs 63 which are brought into action due to the link 56 engaging the arm 60, the springs 63 thus providing increasing support. Adjustment of the main springs in this case may be effected in a manner similar to that previously described. The Specification also contains some mathematical discussion.