GB436619A - Improvements in electromagnetic relays - Google Patents

Abstract

436,619. Light current relays and electromagnetic switches. RICHTER, M. B., (trading as TELEFON FABRIK AUTOMATIC VED M. B. RICHTER), 7, Amaliegade, Copenhagen) Dec. 22, 1934, Nos. 36829 and 36830. Convention dates, Dec. 22, 1933 and Aug. 10, 1934. [Class 38 (v)] An electromagnetic telephone relay in which the contacts are acted upon by a member which is held by a locking pawl in a latched position after an attraction of the armature and which member is returned to the unlatched position by spring action on the next attraction of the armature is provided on this member with an arm which co-operates with the armature to move the member to the latched position on the first attraction of the armature and to release the pawl upon the second attraction of the armature, the position of the arm with respect to the armature being determined by the position of the pawl when in the released and the latched position. As shown in Figs. 4-6 the armature 17 has a springy angleshaped metal plate 22 secured to it near its pivotal point (not shown), the bent-over portion of the member 22 supporting a latching member 26 and a releasing arm 24 on which bear blade springs 31, 32. The member 22 bears against a fixed stop 29 in the unattracted position of the armature and a contact-operating projection 23 engages a contact spring 20<a> in this position. On energization of the electromagnet 18 the armature 17 is attracted and causes a groove 25 in an operating projection to engage the end of the arm 24 and drive down also the springy member 23. In the fully attracted position, Fig. 5, the shaped end of the latching member 26 moves behind a fixed latching shoulder 27 so that on de-energization of the electromagnet the armature returns partially but the springy member 22 remains held by the latching member, Fig. 6. During this partial return of the armature, however, the end of the operating member 24 is released from the groove 24 and the movement of the armature with relation to the springy member 22 causes the pawl 26 and the operating member 24 to be swung slightly to the right. Thus, on a succeeding energization, the end of the member 24 bears on the inclined end face of the operating projection so that the latching member is moved to the right and released from the latching shoulder 27, the springy member immediately returning to its initial position. As shown, the sequence of contact operation during the successive stages of operation of the relay is : contact x closed and contact y open, both contacts x and y open, and contact x open and contact y closed. In a modified arrangement a cam is provided which is operated by the movements of the member 23 to ensure correct sequence of operation of the contacts. The energizing circuit of the relay may be completed over its controlled contacts the coil circuit being completed over different contacts during the various stages of its operation.