GB1524989A - Yarn heaters - Google Patents

Abstract

1524989 Thermal switch HEATING ELEMENTS Ltd 14 Oct 1976 [6 Nov 1975] 46005/75 Heading H1N A yarn heater of the type including a hollow member 2 for heating yarn travelling in grooves 6 in its surface 4, liquid sealed inside member 2 for heating its walls, and an electric heater (not shown) for heating the liquid incorporates a normally closed switch which is opened to interrupt a circuit to the electric heater by the distortion of the member 2 due to excess temperature or pressure of the liquid in member 2. The cross-section of the member distorts to the shape shown in dotted lines in Fig. 1. The switch comprises a fixed contact 10 mounted on a stud 14 fixed to the rear surface of member 2 and a trifurcated snap action blade spring 18 carrying the moving contact 16 mounted on a stud 22 fixed to the rear surface of member 2. A bracket 28 compresses the central tongue 26 of spring 18 and a setting screw 32 carried by a U-shaped bracket welded to the sides of member 2 bears on the spring 18 and normally ensures that contact 16 engages contact 10. On distortion of member 2 the studs 14, 22 which are mounted centrally of member 2 rise relative to setting screw 32 so that the contacts 10, 16 open with a snap action. In Figs. 5-7 (not shown) a microswitch with an operating lever is mounted to one side of the rear surface of member 2 and a plate which abuts the lever to prevent movement is mounted on the opposite side. On distortion of member 2, the plate and lever move relatively allowing the microswitch to open. In another embodiment, a lever pivoted to one edge of the rear surface of the member 2 extends across and beyond the rear surface to actuate a switch spaced from member 2 when member 2 distorts. In Figs. 11-13 (not shown) a shaft attached to the near face of the distortable member 2 actuates the plunger of a switch.