GB622783A - Improvements in electromagnetic relays - Google Patents

Abstract

622,783. Electromagnetic switches. GENERAL ELECTRIC CO., Ltd., COLLYER, J. E., and ROSE, W. R. April 8, 1947, No. 9285. [Class 38(v)] In a frequency relay wherein a switch member such as a cam 24, is rotated successively through N steps by subjecting N tuned reeds such as 4, 5 to successive alternating currents of frequencies corresponding to that of the reeds, the reeds are mounted parallel to the axis of a permanent magnet 1 one pole of which is in contact with a U-shaped laminated yoke 2 provided with an operating coil 6. In the form shown N equals two and the two reeds 4, 5 act on spring pawls 13 engaging ratchet wheels 11, 12 fixed on a spindle 10 which through pinions 20, 21 drives a shaft 14 which in turn through pinions 18, 17 drives an assembly of cams 22, 23 loosely mounted on the spindle 10 and also through pinions 25, 26 drives the contactoperating cam 24. The cams 22, .23, 24 each consist of a wide portion extending over 180 degrees and a narrow portion of the same extent and the cams 22, 23 are oppositely arranged, and adapted in turn to push a pawl out of engagement with its ratchet wheel. In operation, superimposed current, of suitable frequency operates one of the reeds 4, 5 which rotates its ratchet wheel, say 11 till the cam 23 has moved through 180 degrees and pushes the pawl out of engagement. During this movement the cam 24 closes the switch contacts. Later, current of another frequency operates the other reed which is now able to drive its ratchet wheel till the cam 22 pushes its pawl away. During this movement the cam 24 opens the switch contacts. Specification 521,052 is referred to.