Patent GB-366595-A (GB)
Title: Improvements in or relating to switching mechanisms for use in telephone or like systems
IPC: H01H67/16
Filed: 1930-11-07
Abstract: 366,595. Automatic exchange switches. AUTOMATIC TELEPHONE MANUFACTURING CO., Ltd., Strowger Works, and SAXBY, R. N., 36, Millersdale Road, Mossley Hill, both in Liverpool. Nov. 7, 1930, No. 33580. [Class 10 (iv).] Several wiper carriages are provided with common driving means for both longitudinal and rotary motion, the driving means being freed after a wiper carriage has been set, and used to move a second wiper carriage into position. The driving means comprises two spring-driven shafts, for longitudinal and rotary motion respectively, the springs being automatically rewound when the tension is reduced to a predetermined low level. Motion of the carriage is uniform, but the actual wipers are arranged to move step by step over the terminals. The carriages are returned to normal by individual spring sets and a toothed rack, mounted in the switch bank, ensures correct centring of the brushes. The wiper carriage is illustrated in Figs. 1, 5, 7, and 8. When a wiper set is seized magnet 10 operates and its armature 19 moves into the position shown in Fig. 1. Plate 11 moves in a clockwise direction allowing arm 22 to engage a slot in the plate 11 and plate 12 swings to allow pin 26 to engage the teeth 88 in hub 27 which is rigidly secured to hollow rotary shaft 28. The plate 11 can move about, but not along, shaft 15 and this shaft is now moved longitudinally taking plate 11 with it, which, through 22, transmits its movement to the wiper carriage. During this motion a helical spring, attached to the carriage at 85 and to the fixed member 30, is extended. When the required level is reached, the shaft 15 stops and shaft 28 begins to revolve. At the first step 22 moves clear of 11 but 89 engages a suitable slot in plate 38 which prevents the carriage restoring. The wipers are mounted on the plate 35 which trails over the rack 36, mounted in the multiple bank. The shaft rotates at a constant speed but the wipers are held by one of the teeth in 36 until the pressure exerted by the spring 37 moves the plate 35 over the top edge of the tooth whereupon the wipers spring forward, at a rate faster than the shaft is moving, until arrested by the next tooth. This arrangement allows the shaft to be rotated at a high speed and still leaves the wipers in connection with the terminals for sufficient time for testing. During rotary motion the spiral spring 33 is wound. When motion ceases, 10 de-energizes, decoupling the wipers from the shaft. The wipers are held in position by the plate 35 and rack 36. When the wipers are to be released magnet 10 re-energizes and the carriage is again coupled to the rotary shaft. When the wipers are moved clear of the bank, plate 89 moves clear of plate 38 and 10 releases. The carriage is then restored in the longitudinal direction by the helical spring referred to previously, the plate 35 trailing along the edge of the plate 36, and when longitudinal restoration is complete, the wipers are restored in the rotary direction by spring 33. The driving means, which is common to a group of wiper carriages and is mounted in the centre of the shaft, is shown in Figs. 9, 10, and 11. The rotary shaft 28 is coupled, by pins 83, to shaft 50 which is driven by spring 53, the extent of movement being controlled by 58, whilst the vertical shaft 15 is coupled to 73 which is driven through sleeve 54a and wheel 71. The edge of 71 is cut as shown in Fig. 10, and this co-operates with rack 72 to impart a longitudinal motion to shaft 73. The extent of movement of the wiper carriage is controlled by two magnets such as 76, one with an armature 77 and the other, mounted behind 76, with an armature 79. The operation of armature 77 releases the four-arm escapement pinion 78 and allows 56a to drive 71 and the longitudinal shaft 73. Armature 79, in addition to releasing the pinion 58 to allow 53 to drive the rotary shaft, moves the rack 72 out of engagement with wheel 71 and the rack 72 is returned to normal by a restoring spring (not shown). If movement is in respect of dialled impulses, armature 77 is shaped as shown in Fig. 12 to allow movement coriesponding to one level for each digit received. The tension of the spring 53 is controlled by magnet 61 and helical spring 63. When the tension of 53 falls below the fixed level, spring 63 pulls armature 60 and enables contact springs 65 to complete a circuit for 61. Magnet 61 operates and attracts armature 60 and at the end of the stroke 69 slips into the notch in arm 67, which pivots about 87 and is controlled by 68 on arm 60. Springs 65 open and 61 releases. As the armature 60 moves away spring 70 opens the circuit of 61 to ensure a full step and 59 winds the spring 53. This action is repeated until the spring 53 is wound to the required tension when the arm 60 is suspended between its extreme positions.