GB1224004A - Improvements in or relating to snap-action switching arrangements - Google Patents

Abstract

1,224,004. Fluid-pressure control valves &c. DRAYTON HYDROFLEX Ltd. 10 July, 1968 [18 Aug., 1967], No. 38222/67. Heading F2V. [Also in Division H1] A switching arrangement includes a movable member 9 having first and second operating positions, an actuating means 12 and a freely seated diaphragm spring 10, the actuating means 12 being moved linearly in response to temperature or pressure variations such that after a predetermined displacement of the actuating means 12, the movable member 9 is carried by an over-centre snapping movement of the spring 10 from its first to its second operating position. Spring 10 comprises a rim 14 with spokes 11 carrying moving contact 9 at its centre. Actuating means 12 comprises a carrier with a lip 22 located behind conducting ring 15 riveted to housing 2 and having slots with knife-edges 13 bearing on spokes 11 and securing rim 14 against conducting ring 15. A temperature or pressure-responsive device such as a bellows, diaphragm or rod and tube type temperature sensor acts through member 17 on blade 16 secured to carrier 12 to snap over spring 10. Blade 16 is adjustable to vary the operating temperature or pressure by means of screw 18 reached by a screwdriver through opening 19 in housing 2. Fixed contact 4 is adjustable and its position determines whether spring 10 snaps back when the temperature or pressure reduces or whether it must be manually reset by a pin (not shown). It is stated the switching arrangement may operate a valve.