GB270843A - Electromagnetic relays - Google Patents

Abstract

270,843. Tyer & Co., Ltd., and Punter, J. W. Feb. 26, 1926. Electromagnetic switches; switches, latching and unlatching; contact-making relays.-A relay for energizing an electromagnetic device such as the lock of a lever or tablet in railway working has an armature which has a restricted movement on the reception of a weak current and completes its movement on the reception of a succeeding stronger current. As shown in the Figure the electromagnet 2 when energized by a weak current attracts its armature 4 against the spring 5 so causing a contact 6 to engage a contact 12 carried by a lever 8 pivoted at 9. The engagement of contacts 6, 12 completes through contacts 16, 17 the energizing circuit of an electromagnet 20 which attracts its armature 21 so removing the hooked end 22 out of the path of the hooked end 23 of the arm 7 carrying the armature 4. When a succeeding stronger current passes through the electromagnet 2 the arm 8 is moved against the end of a pivoted arm 30 overcoming the resistance of springs 10 and 5 and of an adjustable spring 31 acting on the arm 30 and causing engagement of contacts 32, 33 to complete the energizing circuit of the electromagnetic device. During the intermediate position of the armature 4 a bell circuit is completed at contacts 25, 26. If the stronger current is not preceded by a weak current the contacts 16, 17 disengage before the latching electromagnet 21 can be moved and the bell contacts 25, 26 are arranged to remain in contact while the armature 4 is held against further movement. With currents of intermediate strength the spring 31 is sufficiently strong to prevent the complete movement of the levers 7 and 8 even if the armature 21 has been attracted.