GB978224A - Electromagnetic relay - Google Patents

Abstract

978,224. Electromagnetic relays. OTIS ELEVATOR CO. May 3, 1961, No. 16051/61. Heading H2B. An electromagnetic relay has means for adjusting the position of all the contact springs and of the armature relative to the core, without affecting the spacial relationship between the stationary and the movable contact springs and the armature. The embodiment described comprises a contact pile up assembly 10, a magnetic frame 11, energizing coil 13 mounted on a removable core 14, and an armature 15. Contact assembly 10 comprises two spring pile ups, one each side of the relay, clamped on to a base member 37 by an insulated screw 38 so as to form an interchangeable assembly, each of which comprises a number of co-operating moving and fixed contacts 40, 41 respectively. Insulated washers 42 are interposed between contact springs, locking washers 39 and a base member 37, and have projections 46 which pass through apertures in the contact springs and fit into indentations 47 in the adjacent insulating washers and base member 37, thereby locking the washers and contact springs. A hinge leaf spring 50 riveted to an armature 49 has a portion raised to form a retaining tongue 53 in an armature slot 54. A portion of base member 37 acts as an armature stop. A moving contact driver 60 of insulated material having spaced contact positioning slots 61, is removably secured to armature 49. Two slot apertures in the armature, one shorter than the other, Fig. 4 (not shown), have their centre lines intersecting at 45 degrees. Horizontal slots 62 with slightly convex edges in the driver 60 are inserted into the longer slot and is then rotated into a locked position in the shorter aperture. The driver is prevented from further rotation by the edges of cut-outs 67 in the movable contact springs 40 which are inserted into driver slots 61 and thus actuated by the armature 2. Fixed contact springs 41 have cut-outs with clearance for the driver 60. A fixed contact positioner 68 of insulating material and having a plurality of peripheral grooves is threaded over a threaded stud 69 fastened to a frame flange portion 18. Fixed contact springs 41 are bent and fitted into respective grooves in the positioner 68, which may be raised or lowered by rotating it on the stud 69 by means of a screwdriver slot 73, after which it is locked into position by a nut 74. The armature 49 is bifurcated to engage between vertically spaced shoulders 79, 80 on positioner 68. An armature biasing spring 82 is fitted to the stud 69 by a washer 86 and a self-locking nut 87, and is attached to an annular shoulder 83. Thus any alteration of the armature to pole face gap does not change that of the contact gaps and hence the relay is suitable for voltage or current sensitive operation. The armature to polepiece gap may be reduced so that residual polepiece magnetism retains the armature in its operated position. Connecting a condenser so as to discharge through the relay operating coil enables the relay to be used as a timing relay.