GB1059730A - Thermally responsive electrical switch - Google Patents

Abstract

1,059,730. Thermal switches. TEXAS INSTRUMENTS Inc. Dec. 19, 1963 [Jan. 2, 1963], No. 50201/63. Heading H2B. A switch 10 comprises a snap-acting element 20 (more fully described in Specification 1,045,771) attached at 35 to the end 18 of a rod 14, the end 18 also being fixed at 19 to a supporting frame 100, and end (42) of tongue (30) of element 20 (Fig. 1, not shown) being attached at (130) to a supporting frame 140, such that temperature changes cause differential expansion between rod 14 and tube 12 and relative movement between supporting end 18 and supporting frame 140 to stress element 20 and cause snap-actuation of the switch contacts 44, 162, limiting means being provided to prevent overstressing of the element 20. An angle member having legs 108, 110, is bent from frame 100 and is secured by leg 108 to an adjustment lever member 80, which has a tab 90 to which a tab 144 of frame 140 is secured at 146. A tab 116 projects from frame 100 through a slot in leg 84 of lever 80 and has notches (118), (120) (Fig. 6, not shown) giving a lost motion connection between frame 100 and leg 84 of lever 80. Adjustment of a screw (180) (Fig. 4, not shown) sets the initial stress in element 20 through lever 80 and frame 140. Overtravel in one direction causes the stress in element 20 to be shunted by frame 100 to rod 14, and in the other direction causes frames 100 and 140 to move together to maintain the spacing of supports 140 and 18 constant.