GB276641A - Improvements in or relating to electric switches - Google Patents

Abstract

276,641. Scherbius A., and Ritter, E. R., (trading as Scherbius & Ritter). Aug. 26, 1926, [Convention date]. Bases; cases. - A switch has its contacts working in an exhausted vessel and the mechanical movement of the contacts effected by forces outside the switch transmitted to the contacts through the medium of a resilient part of the vessel. In Fig. 2, a copper vessel 1 has a corrugated diaphragm 2 and is fused to a glass foot 4, the whole being evacuated or fitted with a neutral gas so that only minute movements of the contacts are required for breaking large currents. An operating member 15 welded or soldered to the diaphragm acts on an extension of one contact 13 by means of a glass rod 16, but in a simpler form (Fig. 1, not shown) the moving contact is mounted on the diaphragm which is moved by an external hook thereon. Thermal switches.-Such a hook is shown at 25 in Fig. 3 on a switch 18 on a bracket on a plate 19 which also carries an iron bar or a bar 23 of the material known under the registered Trade Mark Invar adjustable by means of a wheel 26. Increase of temperature causes the plate 19 to expand, whereas the bar 23 retains its original length, the hook 24 moves into engagement with the hook 25 to open the switch 18. The Specification sets out in detail the advantages of mounting the thermal elements externally of the switch, such advantages being in brief (1) the use of materials having large expansions but unsuitable for use in a vacuum owing to occluded gases. (2) the use of beat for attaining a high vacuum. (3) the smallness of the vessel. (4) the heat sensitive member can be put in direct connection with the apparatus to be regulated, and (5) the ease of adjustment of the heat sensitive member. Other means of actuation are by air, steam, or water pressure, or by magnetic relays, and the invention is also applicable to vibrating rectifiers, buzzers and other apparatus having a high rate of oscillation, the latter being facilitated by the relatively small movements possible in an evacuated vessel, and consequently small energy required.