Patent GB-436404-A (GB)
Title: Improvements in manually operable selectors suitable for use in intercommunicating telephone systems
IPC: H04M9/00
Filed: 1934-06-21
Abstract: 436,404. Intercommunication systems. SHIPTON, E., 12, Dartmouth Street, Westminster. June 21, 1934, Nos. 18417 and 22659. [Class 40 (iv)] [See also Group XXXVII] In selecting switches for use in intercommunicating telephone systems and other remote control systems of the type described in Specification 418,388, in order to increase the number of possible lines to which connection may be made, a manually operable selector is provided with one or more wipers which co-operate with two or more groups of contacts, a manually operable selector moving the wiper on to a contact and discriminating means selecting the contact group over which the signal is transmitted. In the arrangement shown diagrammatically in Fig. 5, a single contact wiper is arranged on the first operation of the manual selecting member to engage any selected one of a set of contacts 1 ... 10 and on a subsequent operation, without replacement of the telephone instrument, engages any selected one of a second series of contacts 11 ... 20 which are interleaved between the first series of contacts 1 ... 10. In order to effect this discriminating action in successive operations of the manual selecting member, the driving disc 4, Fig. 3, which is rotated by the fingerhold plate carries a discriminating member 14 which is pivoted thereto. On the first rotation of the finger-hold plate the upturned end 13<a> of the driven member 13 is engaged by a stepped portion 14<b> of the discriminating member so that the contact wiper 15 operated by the driven member stops opposite one of the first series of contacts 1 ... 10. On a second operation, however, the discriminating member is swung to the right by the spring 14<c> so that the driven member is engaged by the advanced leading edge of the discriminating member, the contact wiper then stopping opposite a selected one of the second series of contacts. Automatic locking means released by replacement of the telephone instrument are provided similar to those described in Specification 418,388. These interlocks hold the contact carrier in its displaced position while permitting the return of the finger-hold plate after operation. The contacts 31, 32 which are closed to complete the battery circuit on the return of the finger-hold plate serve also to guide the pin 14d of the discriminating member, moving it against the light spring 14<c> to the left of the slot 4<a> when the parts are in their normal unoperated position so that the sequence of operations already described can take place in successive dialling movements. In a modified arrangement shown in Fig. 6' two separate wipers 60, 61 engage with the two series of contacts 62, 63. A cam 70 operated with the finger-hold plate causes the stepping round of a disc 67 by a pawl 68 on each operation of the finger-hold plate, so moving a contact arm 64 to one or other of a pair of contacts 65, 66. Thus the control of the particular series in which a selected contact is operative is controlled in accordance with the number of operations made by the finger-hold plate. The selection of the particular series of contacts to be brought into circuit may, however, be effected by a directly-operated manual selecting switch.