GB202403A - Improvements relating to selecting devices for telephone systems - Google Patents

Abstract

202,403. Siemens Bros. & Co., Ltd., Petithory, E. A., and Collyer, J. E. May 18, 1922. Automatic exchange selectors.-In a panel type selector the bank terminals are used -for holding a brush set in the desired position and for sending revertive impulses. As shown in Fig. 2, an insulated pawl 7 pivoted to the brush carriage engages the test terminals so as to support the carriage when it comes to rest. The tail 9 of the pawl opens and closes spring contacts 8 as the pawl passes over the terminals. A similar pawl (not shown) co-operates with additional terminals in the bank or with extensions of the appropriate line terminals so as to send an impulse for every group of (say) ten terminals. These additional terminals may be pivoted so as to be put out of engagement with the pawl if the number in a group is altered, or they may be arranged as shown in Fig. 7 on movable bars 19 so that this adjustment may be made in one operation for a number of selectors. Both pawls are disengaged by energization of a magnet 6. More than one terminal may take part in supporting the brush-carriage, and the supporting terminals may be thickened and shaped as shown in Fig. 4. In a modification, the carriage carries two wheels of hard insulating material and having ten teeth which engage with the bank terminals. The teeth in one wheel rock a lever so as to interrupt a spring set as each terminal is passed, and a pin on the other operates a similar lever so as to interrupt a second spring set for every ten terminals. A similar device for use as a group selector has only one wheel which has twenty-five teeth and causes an impulse to be sent once in each revolution.