Patent GB-191324928-A (GB)
Title: Improvements in Switching Apparatus for Telephone Exchange Systems.
IPC: H01H67/12
Filed: 1913-11-01
Granted: 1914-07-23
Abstract: 24,928. Western Electric Co., [Woodward, F. T., acting for Western Electric Co.]. Nov. 1. Automatic exchange systems and apparatus. - In a selector in which a longitudinallymoving shaft carries a number of sets of brashes co-operating witb different sections of a vertical row of terminals, the brushes are mounted on flexible arms, and each set is provided with a device by which they are normally spaced apart so as to travel clear of the terminals, as shown in Fig. 3. Means are provided by which, in the initial stage of the movement of the shaft, the spacing- device of one of the sets. of brushes is tripped, so that during the further movement of the shaft, the brushes of the selected set make contact with the terminals over which they move. In the selector described, there are five sets of brushes each co-operating with 100 sets of terminals. The brushes are multipled together by wires which pass through the interior of the shaft, connexion with the external circuits being made by sliding contacts. (1) Brush-choosing mechanism. The spacing-device for holding the brushes cut of contact with the terminals comprises a pair of rollers 30, Fig. 5, carried by a frame which is pivoted on a pin 28. In the preliminary brush-choosing stage of the operation of the selector, when the shaft 8, Fig. 1, has been raised a distance depending on which set of brushes is to be selected, a magnet 45 is energized to rotate a tripping-rod 37. A finger 42, Fig. 6, on the rod 37 engages a lug 31 on the spacing-device of one of the sets of brushes and hooks it with a clip 43, so that the further movement of the shaft 8 rocks the rollers 30 clear of the inbent portions 34 of the brush springs 17, 18, allowing the brushes 1, 2, 3, 4 to move into engagement with the terminals 5, 6, 7. The rod 37 has a tripping-finger 42 for each set of brushes, but these are spaced at different distances above the lugs 31, so that only one set of brushes is released. The fingers 42 have a certain amount of rotative freedom on the shaft 37, so that when a finger 42 which has been stopped by engagement with a lug 31 is released by the lug escaping in its upward travel, the finger moves on, under the influence of a spring 41, Fig. 6, into alinement with the other fingers, so as to be clear of the lugs 31 in the further travel of the shaft 8. When the selector is released, the spacing-rollers 30 are restored to their operative position by the engagement of an arm 32 with a frame plate 10. (2) Driving-mechanism. The upward movement of the shaft 8 is effected by low- and high-speed rollers 54, 54<1> with which the shaft is engaged by means of idler - wheels 56, 56<1> controlled by magnets 65, 65'. The low speed roller is in action during the brush-choosing and units' stages, which are controlled by the interrupters 81, 80, while the high-speed roller is in action during the 'tens' selection, which is controlled by the interrupter 77. A reverse-motion roller 54<11> is brought into action by a magnet 65<11> to restore the shaft to its normal position when the release magnet 86 is energized.