Improvements in snap action electric relays

摘要

850,983. Thermal switches. SIGNALSTAT CORPORATION. May 29, 1958 [June 6, 1957], No. 17224/58. Class 38 (5). A snap-action relay comprises a vane 20 of resilient metal having a pair of deformations 21 along one diagonal making it into a shallow inverted vee about the said diagonal, and a metal strip 30 attached to the ends of the said diagonal so as to stress the vane into an erect vee about the other diagonal as shown in Fig. 2. Expansion of strip 30, due to heating by high-resistance wire 35, allows the vane 20 to snap back into the preformed vee condition. The vane 20 is mounted at 28 on a bracket 22 fixed to an insulating base 10 at 23 and connected to terminal 11. A contact 27 on the vane co-operates with a contact 25 insulatingly carried on the bracket 22 and connected to terminal 12. One end of heater wire 35 is connected to terminal 13 via a bracket 31, and the other end is secured to a contact 40 insulatingly mounted on a corner of the vane 20 so as to engage contact 45 connected to terminal 14 by bracket 46. Contacts 25, 27 are normally open and contacts 40, 45 normalled closed (as in Fig. 2), these conditions being reversed with a snap action when strip 30 is heated. Specifications 761,713 and 769,505 are referred to.