GB942106A - Fluid pressure actuated electric switch device - Google Patents

Abstract

942,106. Thermal switches. RANCO Inc. Jan. 10, 1962 [Jan. 10, 1961], No. 911/62. Heading H2B. A relatively slim snap-action switch which may be mounted between the closely spaced surfaces of an insulated wall of a refrigerator comprises a housing having terminal lugs at one end and a tube 38 (containing thermally responsive fluid) extending from the opposite end. An insulating member 14 provides a side wall 14b of the housing and also an end wall 14c which forms two recesses to accommodate two terminal lugs respectively. A rigid conductor 15 is secured to wall 14b and extends into recess 14d forming a terminal 15c, while a similar terminal is provided by a conductor 22 extending into a corresponding recess behind 14d. A fixed contact 22a is carried by conductor 22 and a moving contact 20b is carried on a beryllium copper strip 20 secured to the inner end 15d of conductor 15. Strip 20 has an aperture to receive snap-action mechanism comprising a toggle-bar 25 and C-spring 26. A spring arm 28 secured to end 15d has a depending tongue 28c embracing toggle bar 25 and is depressible by an insulating member 35 secured to a lever 32 which is pivoted on a spindle 34 extending across the housing. Lever 32 has a raised central portion 32d arranged to be acted on by capsule 36 connected to the tube 38. A spring 42 extends between the free end 32b of lever 32 and a lever 40 which is pivoted on the spindle 34 and bears against a cam 47 rotatable by knob 49 for adjusting the operating temperature. A screw 30, threaded in conductor 15, engages toggle bar 25 to control the temperature differential of the switch. The switch may be rendered inoperative by turning cam 47 such that an extra high part 47b engages lever 40 causing an arm 40c thereof to rise and prevent movement of lever 32 regardless of pressure changes in capsule 36. A cover 50 of flexible insulating material is provided to prevent conductor 20 or rivet 16 from contacting a conductive panel of the refrigerator wall.