GB696642A - Improvements relating to thermally-actuated electric circuit interrupting devices - Google Patents

Abstract

696,642. Thermal switches. TRICO-FOLBERTH, Ltd. June 19, 1951 [May 30, 1950], No. 13521/50. Class 38 (v) A thermal flasher, e.g. for vehicle direction indicator lamps, comprises a contact-carrying member 3 tending to move in one direction and normally restrained from doing so by a conducting wire 18 which, when heated, expands and allows the member 3 to move in said direction, thereby closing contacts to shunt the wire 18 which thereupon cools, and so on. The member 3 is slotted at 4, 5 to form three strips 3a - 3c, the strip 3a carrying a contact 23, and the strips 3b, 3c, preferably being shortened, as by forming an indentation therein, so as to bow the strip 3a. The wire 18 is fixed at one end to an ear 7 struck up from member 3 and at the other, to an insulator 19 carried by an ear 20 struck up from a strip 11 carrying the co-operating contact 22 and fixed to the base 1, together with an insulating plate 10 and the member 3, by a screw 14, the other end of member 3 being secured with a little play at 9. A resistance 21 is connected between the wire 18 and screw 14. The device may be adjusted by adjusting the resistance 21, or the screw 9, or a screw 13 which secures the turnedover end 12 of the strip 11 to the base, or by an adjustable tension spring stretched between the ear 7 and a rotatable shaft, or by adjustment of the open position of contact 23 by a screw (not shown) bearing against the strip 3a. The member 3 may be in the form of a disc from which two segments are removed to leave an annular part fixed to the base and a diametral strip 3a, Fig. 5 (not shown). One side of the source is connected to the strip 11 either at screw 13 or screw 14, the other side being earthed, and the load is connected to the member 3 either at 9 or at the other end of the member.