GB662428A - Improvements in or relating to electric switches suitable for telegraph transmitters - Google Patents

Abstract

662,428. Retractive switches. TELETYPE CORPORATION. Dec. 30, 1949. [Jan. 13, 1949] No. 33364/49. Class 38 (v). A switch for use in a high-speed telegraph transmitter comprises a pair of movable contacts 38 carried by a T-shaped conducting lever 36 pivoted at 44 to an arm 43 urged about a pivot 41 by a spring 46. The lever 36 is normally held in an extreme position by an operating lever 37 so that only one pair of contacts 34, 38 is engaged. On movement of lever 37 to close the open pair of contacts 34, 38, both pairs are closed for a short interval and then the appropriate contact 38 pivots on its fixed contact 34. The arrangement minimises contact-bounce. To further minimise bounce, the lever 36 may have a heavy mass. A pointer 48 facilitates setting the switch. In use the +ve battery terminal may be connected to one of the contacts 34 and the output taken from the T-lever 36. The Specification as placed open to inspection under Sect. 91 also describes a construction, Fig. 3 (Cancelled), in which a pair of movable contacts 18 are soldered to a flexible conducting strap 16 secured to an insulating block 11 having stationary contact pins 13. A block 19 secured to the strap 16 is urged against a dome-shaped support 28 by a pin 21 freely extending therethrough and connected to a spring 22. The contacts 13, 18 are normally open, but on movement of a lever 24, fixed to the block 19 from the central position, the block 19 first rocks on the support 28 until a pair of contacts 13, 18 engage, whereupon on continued movement of the lever the contact 18 pivots on its fixed contact 13 and is urged thereagainst by the spring 22. In a modification, Fig. 1 (Cancelled, not shown), the support 28 is omitted. This subject-matter does not appear in the Specification as accepted.