SE328049B - - Google Patents

Abstract

1,175,997. Fluid actuation of switches; snap-action switches. PATINVEST PATENTUND INVESTMENT A.G. 7 July, 1967 [12 July, 1966], No. 31495/67. Heading H1N. An electric pressure-controlled snap switch having at least one contact spring 10 projecting between fixed contacts 13, 14 and the operation of which may be controlled by the movements of an element which is subjected to the pressure of a liquid or gas and then acts on an intermediate control lever 5 which is connected to contact spring 10 by a snap spring 17 and is also acted on by an adjusting spring 6 has the bearing points 18, 19 for snap spring 17 disposed relative to the pivot arms 26 of control lever 5 so that the torque M s exerted by snap spring 17 on the control lever is opposed at least within the area adjacent to the snap-over points to the torque M, exerted by adjusting spring 6 on control lever 5. Torque M s equals the product of snap spring pressure S and distance b. Torque M j equals the product of adjusting spring pressure J and distance a. Pressure from a diaphragm is applied by a tappet at D on control lever 5. The strength of spring 6 may be adjusted by a set-screw. A graph is given (Fig. 6, not shown) for M s , M j, M s + M j for high and low initial tension of spring 6 against distance of travel of control lever 5. The position of fixed contact 13 may be adjusted by a set-screw. Contact spring 10 is highly elastic at least between contact 11 and bearing 18 to assist the snap-action, and to have a cleaning and anti-chattering effect on the contacts. The snap spring may be a coil spring or barrel spring. The switch described is a three-phase switch having one diaphragm actuating three switch systems each comprising a contact spring, a pair of associated fixed contacts and a control lever and adjacent switch systems are disposed in reversed positions to each other.