GB407205A - Improvements in and relating to electric control switches - Google Patents

Abstract

407,205. Rocking-bar controllers; switches held set and freed mechanically. INTERNATIONAL GENERAL ELECTRIC CO., Inc., 120, Broadway, New York, U.S.A.- (Assignees of Allgemeine Elektricitats-Ges. ; 2, Friedrich Karl-Ufer, Berlin.) April 6, 1933, No. 10348. Convention date, April 6, 1932. [Classes 38 (iii) and 38 (v).] An electric switch has a contact normally operated by a principal cam, but alternatively operated by an independent auxiliary cam moving from a condition in which it is previously set in response to operation of the switch contact by the principal cam. The invention is described with reference to a railway motor control switch. Upon rotation of a shaft 1 and cam 3, to close contacts 10, 11, a roller 13, situated on the curved surface of a freely mounted cam 5, causes the latter to rotate and raise a piston working in a cylinder 8, so that, upon overload, no-voltage, or release of a deadmans handle, the piston is returned to the position shown, by compressed air, and the cam 5 is rotated to open the contacts 10, 11, independently of the position of the cam 3. In a constructional example, a detent 6 by which the cam 5 is coupled to the piston, is so shaped that its outer surface forms the co-operating surface for the roller 13. The release mechanism 8, 5, may be locked in its operated position, so that the compressed air supply to the cylinder 8 need not be maintained. This locking may be released by energization of a magnet through contacts closed only between the zero and first positions of the main controller, and contacts closed only when the locking mechanism is in its effective position. As applied to a tapped transformer control system, several switches are provided, all released by a common pneumatic drive.