Patent GB-653961-A (GB)
Title: Improvements in or relating to electromagnetic contact-making mechanisms
IPC: H01H67/26
Filed: 1948-01-15
Abstract: 653,961. Automatic exchange switches. ERICSSON TELEPHONES, Ltd., and CROWE, D. C. Jan. 15, 1948, No. 1218. [Class 40 (iv)] In a switch comprising a plurality of contact sets, electromagelectromagneticallyselecting means and electromagnetically - controlled operating means, the selected contact set is operated by the release of both the operating and the selecting means and is released by the reoperation of the operating means. A crossbar switch, Figs. 1, 2, has five rows of contact sets mounted on shelves 10 fixed between the main frame members 9, each row being formed of two groups of six contact sets on either side of an operating magnet 49. Two groups of six selecting magnets having armatures 12 and a relay magnet having an armature 4 are mounted in common blocks of magnetic material 14 above and below the contact banks. The magnets are similar to those described in Specification 627,952, [Group XXXVII]. Select. ing rods 6 carry projections 18 engaging the armatures 12 and claws 8 for selecting the required contact set, and also serve to operate an additional group of contact sets 1 situated above the upper block 14. Spacing blocks 25, Fig. 5, mounted on the shelves 10 at the ends and between the contact sets support members 55, Fig. 6, of insulating material to which are riveted contact bus-bars 38 connected by wires 37 to the terminals at the rear of the switch, and also support the fixed members 60 of contact-springs 26 similar to those described in Specification 576,608, [Group XXXVII]. The contact assemblies are enclosed by plates 32, and secured by screws 35 and locating-pins 36. The actuating mechanism for each row is shown in Figs. 2, 3, 7. A tray 11, hinged at the rear to the shelf 10, is lifted to a normal position by springs 23 secured to the fixed block of the operating magnet 49 and is operatively connected by a strip 22 to the magnet armature 24. Two plates 15, pivoted to the front of the tray 11, are urged to an upright position by coil-springs 61 and are, for the greater part of their length, cut away and flanged to form retaining catches 51. A cranked setting- member 34 positioned under each contact set is attached to a flexible spring-plate 65 clamped between blocks 46, 47, fixed to the tray 11 and a detent 50 is stamped out from each member 34 and is normally positioned below the associated retaining catch 51. Energization of a selecting magnet lifts a rod 6 and positions its claws 8 immediately beneath the setting members 34 of the selected column. Subsequent energization of an operating magnet 49 causes the relevant armature 24 and tray 11 to pivot downwards, and during this movement the armature 24 engages and rotates a U-sectioned link 21 mounted on screws 41 secured to the magnet block, and a U-shaped arm 16 pivoted on the link 21 slides forward along a guideplate 45 to engage the plates 15 to displace the retaining catches 51. Near the end of the downward movement of the tray 11, the plates 15 disengage from the arm 16 and return to their normal position relative to the tray, and one of the retaining catches 51 is now positioned underneath the detent 50 of the selected setting  member 34 which, owing to a raised claw 8 has been retained in its normal position. The selecting magnet may be released for a fresh selection to be made. When the operating magnet is de-energized the tray 11 is returned to its normal position by the spring 23 and the retaining catch 51 lifts the selected setting member to operate the required contact set. Re-operation of the operating magnet actuates the arm 16 to release the retaining catch 51, thus permitting the raised setting member to resume its normal position relative to the tray 11, to release the operated contact set.