Patent GB-702194-A (GB)
Title: Co-ordinate type electro selector switch
IPC: H01H67/12
Filed: 1948-12-17
Abstract: 702,194. Selector switches. AUTOMATIC ELECTRIC LABORATORIES, Inc. Dec. 17, 1948 [Dec. 18, 1947], No. 32725/48. Class 40 (4) A switching apparatus of the X-Y coordinate type comprises a primary carriage movable in e.g. the X direction, a secondary carriage carried on the primary carriage, and movable relative thereto in the Y direction, the secondary carriage carrying the moving switch contacts, and a common drive for selectively positioning both carriages through a ratchet and pawl transmission and for zeroizing both carriages through a further ratchet and pawl. As shown, Figs. 1, 1B, frame members 401, 402, 403, mount a plurality of switch mechanisms such as that shown at 100B, in a vertical tier for co-operation with a single contact bank 65. Each switch mechanism comprises a base plate 32 mounting a guide rod 31 along which the primary carriage 16 slides in the X direction, the secondary carriage 9 carrying the moving contact spring pairs 1-2, 3-4, 5-6, 7-8 being slidable in the Y direction on the primary carriage. Energization of the drive magnet 75B, Fig. 1B, steps, through a toggle link 119, lever 126 and pawl 127, a ratchet wheel 129, which through a pinion 142 steps a rack-bar 30 to the right. In the normal position of the carriages, the primary carriage is locked to the rack 30 by a spring-biased detent 40, and moves step-bystep with the rack to the right as the drive magnet 75B is pulsed. When the selected position along the X direction is reached, a shift magnet 96B is energized, which, through its armature 148 and links 150, 99, 102, 46 rocks the detent 40, which is pivoted to the primary carriage at 39, to unlock the primary carriage from rack 30 and at the same time lock it against further X movement by means of a detent 41, rigid with 40, which engages in a notched locking plate 44 fixed to the base plate. Subsequent energizations of the drive magnet 75B step rack 30 to the right as before, the rack now stepping the secondary carriage 9 through the coaxial gears 29, 25, Fig. 1, and the rack 24 rigid with the secondary carriage. The shift magnet 96B may be released after the secondary carriage has made one step when the locking detent 41 is held in the operative position by the toothless portion of the rack 30. The carriages are reset (zeroized) by energizing a release magnet 105B, which rocks the spring-biased lever 126 so that the pawl 128 is rendered operative instead of the pawl 127. Subsequent energizations of the drive magnet 75B then step a ratchet wheel 130 coaxial with the ratchet 129 so that the rack bar 30 is stepped to the left to reset the secondary and then the primary carriage. The primary and secondary carriages operate respective off-normal contact sets 47, 52 and the primary carriage in addition operates impulsing springs 58 at each step thereof, and advances a wiper over control contacts in accordance with its X position, Figs. 3, 4 (not shown). The Specification as open to inspection under Sect. 91, also describes another embodiment, Figs. 1A, 2A (not shown), in which the rack bar is stepped to the right against spring bias by the drive magnet. The rack-bar and hence the carriages are reset by energizing a release magnet which disengages the locking and driving pawls so that the rack-bar is returned to normal by its biasing spring. This subjectmatter does not appear in the Specification as accepted. The Specification as open to inspection under Sect. 91 also describes another modification, Figs. 1C, 2C (Cancelled), in which the rack 30 is biased to the right by a spring 179 and moved thereby to set the carriages as before under control of an escapement mechanism operated by permanent operation of a release magnet 105c and intermittent energization of a drive magnet 75c. Energization of the release magnet 105c rocks a U-shaped member 167 anticlockwise, Fig. 1C, to remove a locking detent 169 and the driving pawl 168 of the drive magnet 75c from the teeth 30a of the rack 30 which is however held against movement by detents 176a, 177 engaging in slots 178 of the rack and forming the escapement. Intermittent energization of the drive magnet 75c correspondingly moves the driving pawl 168 to the left against its biasing springs 162a, 191. A lug 170 on the driving pawl 168 correspondingly rocks a U member 172 against its biasing spring 173, a projection 175 on member 172 alternately engaging and releasing the detents 176a, 177 from the slots 178 in the rack, permitting the rack to escape to the right under the action of the spring 179 in a step-by-step manner, one complete step for each energization of the drive magnet. To reset the rack, i.e. to move the carriages back to normal, the release magnet 105c is de-energized, whereupon the U member 167 rocks clockwise under the stress of the spring detent 169, which with the driving pawl 168 re-engages the rack 30a. Intermittent energization of the drive magnet 75c then actuates the pawl 168 to step the rack 30 to the left back to its normal position against the bias of the spring 179. The U member 172 is not actuated by the lug 170 in this case owing to the lateral shift thereof by release of the release magnet. The shift magnet 96c, which functions as in the preceding embodiments to apply the movement of the rack to one or other of the carriages, actuates a further contact spring set 187. This subject-matter does not appear in the Specification as accepted but is included in divisional Specification 702,258.