GB734612A - Electromagnetic relay - Google Patents

Abstract

734,612. Electromagnetic switches; switch contacts. ALLIED CONTROL CO., Inc. Jan. 6, 1953 [Feb. 28, 1952], No. 394/53. Class 38 (5). An electromagnetic switch comprises an operating coil 10 enclosed by two cup-shaped pole-pieces 12, 14 whose outer edges meet at 16, the inner edges being spaced apart to form a gap 18. A pole-piece bushing 22 fixed in the pole-piece 14 slidably receives an insulating switch actuator 42, whilst a brass liner 24 in the pole-piece 12 slidably receives a cup-shaped armature 26. The armature is urged away from the pole-piece 22 by a tension spring 28 connected between crimps 30 on the armature and the head of a screw 32 initially adjustable in a brass plate 34. A bracket 50 spot-welded to the pole-piece 14 has four depending arms 56 whose ends engage peripheral notches in an end plate 48 (Fig. 7, not shown), to space the latter from the pole-piece. The plate 48 carries in glass inserts 64 an inner and an outer circle of terminals 62, 60, respectively, there being two terminals 60 for each terminal 62. The inner terminals 62 support U-shaped movable contacts 79, the free end of each contact 79 being positioned between a pair of fixed contacts 80, 82 supported by an adjacent pair of terminals 60 situated one to each side of the contact 79. The drawing shows six sets of contacts 79, 80, 82. Normally, the contacts 79 engage the upper contacts 82 but on energization of the coil 10 through a pair of further terminals 66, 68, the actuator 42 is moved against its spring 46 by the armature 26 and a flange 44 on the actuator moves the contacts 79 away from contacts 82 to engage the lower contacts 80. The contacts 79 are curved along the line 4, 4 to impart rigidity, Fig. 3. Each contact 79 80 or 82 is connected to its terminal by sliding a sleeve 94 of appropriate length over the terminal and passing an extension 96 of the sleeve through an aperture in the contact whereupon the extension is riveted over to hold the contact against a sleeve flange 95, solder 98 then being applied, Figs. 1, 9. A magnetic outer casing 84 is sealed by solder 40 around an opening for the screw 32 and by solder 86 to the end plate 48. Before applying the solder 40 the casing may be evacuated and then filled with an inert gas, the gases leaking past the screw 32. Specification 734,670 is referred to.