GB434564A - - Google Patents

Abstract

434,564. Electromagnetic switches. LANDIS & GYR AKT.-GES., 1, Hofstrasse, Zug, Switzerland. Aug. 31, 1934, No. 25101. Convention date, Sept. 15, 1933. [Class 38 (v)] In a step-by-step switch, on successive energizations of an operating motor, the operating shaft of a contact device is moved through a definite angle in the same direction against the action of a spring which returns the rotor of the motor to a starting position after de-energization of the motor coil. As shown in Fig. 1 the motor drive comprises an induction disc 5 with driving magnet 4 which rotates toothed gearing 6 the large wheel of which is held against a flat plate 9 secured to a shaft 7 by a spring 8. The rotation of the gearing on energization of an operating motor rotates the shaft 7 against a spring 12 through an angle between fixed limiting stops 14 during which rotation a pawl 19 carried by a cranked member 11 secured to the shaft 7 engages a tooth of a three-toothed ratchet wheel 16 mounted on a contact-operating shaft 15 stepping round an operating cam 17 which in one of its operating positions engages a roller 27, Fig. 4, carried by a spring-supported contact arm 26 and brings contacts 25, 23 out of engagement. The cam member 17 is formed with two operating surfaces 29, 30 so that it may be removed from the contact shaft and reversed so varying the angular position at which operation of the contacts takes place. The contact shaft may be fitted with an external operating handle 18 so that the contact shaft may be rotated manually if the switch has failed to operate and thus fallen out of step with other switches which are energized simultaneously. On cessation of the operating current the shaft 7 and the driving disc are returned by the spring 12 to their initial positions the tooth 19 slipping over a tooth of the ratchet wheel on the contact shaft in readiness for a succeeding operation.