GB467178A - Automatic telephone exchange switching systems - Google Patents

Abstract

467,178. Automatic exchange switches. AITKEN, W. Dec. 11, 1935, No. 34289. [Class 40 (iv)] A panel switch is designed so that the group sizes may be adjusted by moving the wipers on the wiper shaft. As shown the panel is built up from continuous strips having projections which are twisted through 90‹ to form the terminals and the wipers are arranged to bridge the spaces between the terminals and vertical bars. The wipers which are relatively displaced angularly and axially are adjustably secured to the shaft 15 by means of screws 33. In use, a particular set of wipers is first selected by delivering impulses to the rotary magnet 16 controlling a ratchet 27 keyed to the wiper shaft. Magnets 18 are then actuated to move the wiper shaft laterally against the springs 23, 24 so that the wipers (or, preferably, the test wiper only,) engage their terminals. In a modification, Figs. 4 and 5 (not shown) this lateral movement is imparted by a steel tape instead of by direct stepping of the carriages 21. The wiper shaft is then moved vertically by the magnet 17 and when an idle or wanted line is found the lateral movement of the wiper shaft is completed if necessary. In the case of numerical stepping by the magnet 17 any lateral movement may be deferred until the end of such movement. Upwardly and downwardly hunting switches may be arranged on opposite sides of the panel and may share some or all of the trunks. For example in a group of ten outlets, the first three trunks encountered by each type of switch may be individual and the remaining four, common.