GB562645A - Improvements in or relating to relays for amplifying small forces - Google Patents

Abstract

562,645. Relays for amplifying movements to indicating apparatus. NEGRETTI, H. N., NEGRETTI, P. E., and GREENING. E. F. Oct. 9, 1942, No. 14217. [Class 118 (ii)] [Also in Groups I, XVIII, XIX, XX. and XXXVI] A relay for amplifying small forces comprises a pivoted lever to be loaded with the small force and adapted to transmit the load to a pallet against the pressure of a fluid from a nozzle, affording a small escape, in a tapping from a fluid pressure supply line, leading to means for directly operating an indicator, recorder and/or an instrument of control, so that a small movement of the pallet due to change of loading varies the escape and causes the pressure in the supply line to build up or subside to a valve balancing at the nozzle the load transmitted to the pallet. As shown in Fig. 1, the invention is applied to the amplification of the difference between the external and internal pressures acting on a capsule 1, which may be of the type described in Specification 561,220, [Group XIX]. The boss of the capsule is connected to a lever 5 by a flexing strip 9 and by a compression spring 8 which prevents overloadiiig. Expansion of the capsule is limited by an adjustable stop 13. A bimetallic strip 15, adjustable lengthwise, is connected by a light compression spring 17 to one of several notches 18 in the lever 5, so as to compensate for temperature changes within the casing. The lever 5 is fulcrummed to a flexible diaphragm seal 6 and is acted on at its other end by a tension spring 19, finely adjustable, Fig. 2 (not shown). A dashpot 26 damps vibrations in the lever. A bearing block 27 is frictionally adjustable along the lever and bears on a strut 28 acting on a block 29 bearing a pallet 30 controlling the escape of pressure fluid from a nozzle 33, tapped off a pipe-line with a constriction, Figs. 2 and 3 (not shown), so that the pressure builds up or subsides quickly to control an indicator, recorder or controlling device. In Fig. 5, the force applied to the lever 5 is derived from a temperaturesensitive element connected to a Bourdon tube. In Fig. 6, humidity is measured by a hygroscopic element 47 through a light tension spring 48. Fig. 7 shows an indicating instrument operating the lever 5 through a spring 52, lever 5], and cam 50. The invention is applied to a weighing device in Fig. 8, and Fig. 9 shows an electrical meter in which a solenoid 57 is actuated by a coil 58. Specifications 226,137, [Class 106 (ii)], and 341,365, [Group XIX], also are referred to.