GB437826A - Improvements in thermally-operated electric switches - Google Patents

Abstract

437,826. Thermal and magnetic switches. SANDERS, H. C., Somerton Works, Newport, Monmouthshire. May 26, 1934, No. 15718. [Class 38 (v)] A thermally. operated switch has a plurality of switch members which have armatures mounted on the ends of flexible contact-carrying members, a plural. ity of magnets for returning the armatures to close the circuits and an adjustable member which is set in relation to the flexible contact-carrying members to regulate the temperatures at which said switch members cutout. Asshown in Figs. 1 and 2 a rod 5 and sleeve 4 having different coefficients of expansion is adapted to operate two flexible switch arms 7, 8 the anchored ends 9, 10 of which are connected to a common terminal 11. The free ends of the arms 7, 8 are provided with armatures 13, 14 disposed below the poles of permanent magnets 17, 18 contacts 15, 16 on the armatures being adapted to project, as shown in Fig. 4, upwardly between the poles of the permanent magnets into engagement with adjustable fixed contacts 21, 22, carried by bent-over arms 19, 20. Where the flexible switch arms are engaged by the flanged edge of an insulating washer 24 on the rod 5 they are kinked as at 25. The position of this operating projection may be adjusted by a screwed thimble 23 working on the threaded'upper portion of the rod 5, which thus forms a common adjusting means to regulate the temperatures at which the two switch members cut out, each member being also independently adjustable by movement of its relatively fixed contact 21 or 22. The magnets and their co-operating armatures ensure a rapid breaking action of the switch arms. The two contact arms may thus be arranged to control the different circuits at different operating temperatures.