GB587111A - Improvements in or relating to thermostats - Google Patents

Abstract

587,111. Thermostats. THERMEGA, Ltd., and SINGLETON, S. A. Dec. 15, 1943, Nos. 21065/43 and 24428/44. [Class 64 (ii)] [Also in Group XXXVII] A thermostat comprises two bimetallic strips 1, 2 movable in opposite directions on change in temperature, an electrical contact 4 on strip 1 and a blade spring 5 mounted parallel to and separately from the strips and having a cooperating contact 6 under the control of the strip 2 or of both strips. The bimetallic strips 1, 2 are mounted on opposite sides of an insulating holder 3, and adjacent and outside the strip 2 (Fig. 1) is mounted the blade spring 5 which presses the contacts together until, when the strips move apart on change of temperature in a given direction, the blade 5 first follows the strip 1 and later, when pressed by the strip 2, the blade moves away to open the contacts. In Fig. 4 the spring blade 5 is mounted between the strips and is bent at 17 to press at a point intermediate its length on a projection 18 on the strip 2 so that on a change of temperature in a given direction, the strips move apart and the blade also moves to open the contacts. The strip 2 is connected by a resilient strip 19 to the holder 3, and an adjustment screw 20 on a bracket 21 bears on the strip 2 to adjust the initial tension on the blade 5 and the distance apart of the contacts 4, 6 to regulate the temperature at which the contacts open. The contact 4 is adjustably screwed into the blade 1. The members 1, 2, 5 are held on the holder 3 by bolts 10 with insulating sleeves 12 and mica strips 13. The holder 3 carries terminals 16 and resilient strips 14 bent to hold the thermostat centrally in a glass tube, which may be evacuated or contain an inert gas.