Patent GB-252226-A (GB)
Title: Improvements in railway-platform and other like indicators
IPC: B61L25/04
Filed: 1925-02-06
Abstract: 252,226. Relay Automatic Telephone Co., Ltd., Johnson, B. B., and Inman, T. M. Feb. 6, 1925. Apparatus for signalling any of a number of possible indications.-Relates to railway platform or the like indicators wherein the times of departure and arrival, the number of the platform and other data may be selectively displayed. Each indicator D11, D 12 &c., Fig. 1<a>, which shows the general arrangement of departure " indicators, has a number of display panels PP which are selectively associated by relays P1R controlled by keys at the control office with a " decoder " TD1, TD2, &c. common to all the panels of an indicator and connected to a common transmitter or "coding " apparatus at the control office. Each panel PP is divided into sections in which the platform number and time are displayed. Each station name may be illuminated by a lamp controlled by a separate switch but the platform numbers and " departure " times are selected from a central control point by means of manually operated cams which select different combinations of line wires depending upon the cam settings and thereby operate relay selecting mechanism. This mechanism marks contacts on step-by-step hunting switches which adjust the display apparatus to the desired position. Several indicators are located at different points of a railway station and the arrangement is such that the same indications are displayed in corresponding panels on all the indicators. Figs. 3, 4 and 5 show in detail the circuits associated with the " departure " indicator. " Departure indicator." Assuming that a departure indication is to be displayed in corresponding platform panels on all the indicators, the hour, minute tens and minute units cams TCC, Fig. 3, are set in the appropriate positions. Figs. 3, 4 and 5 show mechanism for indicating time only, but the apparatus for selecting platform numbers is similar. Alternatively, the platform numbers may be invariable. Each set of cams TCC selects a particular line or combination of lines and the corresponding relay or relavs R1 - - R4 in the groups of relays HD, MtD, MuD, Fig. 4. Keys PPK1, PPK2, &c. at the control point serve to associate the time coding apparatus with the corresponding panels in all the indicators. When the key PPK1, PPK2, &c. which corresponds to the panels to be selected is operated, the corresponding relay HR1, HR2, &c. is energized to (1 lock up, (2) illuminate the corresponding lamp PPL1, PPL2, &c., (3) operate the selected relays in the groups HD, MtD, MuD and (4) operate the relays P1R and thereby sedect the corresponding panels on which the indication is to be displayed on all the indicators. The relay P1R1, Fig. 5, is connected in parallel with similar relays associated with the remaining indicators. When the relays of the groups HD, MtD, MuD are operated, the relays SRH, SRt, SRu are connected to contacts on the switching mechanism A, B, C, Fig. 5, which correspond to the selected numerals of the coding apparatus at the control point. When the relays, such as P1R1, are operated, the relays CH, CMt, CMu close the circuits of the switch stepping magnets SMH, SMMt, SMMu, which energize slowrelease magnets SMH, STt, STu to de-energize the relays CH, CMt, CMu and consequently the magnets SMH, SMMt, SMMu. When these magnets are released the wipers of the switches are moved one step. Upon de-energization of the stepping magnets, the relays STH, STt, STu release their armatures after an interval of time and energize the relays CH, CM, CMu to again operate the stepping magnets and slowacting relays and thereby operate the switches through a second step. This operation continues until the wipers reach the selected contacts, when circuits are completed over the relays SRH, SRt, SRu through the selected contacts to the slow-acting relays STH, STt, STu, so that although the stepping magnets have released their amatures, the circuits of the slow-acting relays are maintained and the step-by-step movements of the wipers are stopped. The indicators, which may comprise display plates mounted on an endless chain, are moved into their required positions by the switches. The relays SRH, SRt, SRu and the corresponding relays in the other indicators complete a circuit for a relay SR which opens the locking circuit of the operated relay in the group HR1, HR2, &c. and restores the apparatus to normal. The corresponding lamp in the groups PPL1, PPL2, &c. is extinguished to inform the operator that the indications are correctly displayed. Arrival indicator. The arrival indicator, although having different display equipment operates in a similar manner to the departure indicator. Provision is made for the display of the time of arrival, the station names, the arrival platforms, and the minutes late. The indicator is controlled from a distant point by apparatus similar to that provided for the departure indicator. Several of the panels may be associated with invariable origins. In this case, the origin coding cams, when in their normal position, short-circuit the contacts of the " origin " supervisory relay, the function of which is similar to that of the relays SRH, SRt, SRu, Fig. 4, so as to ensure the release of the control mechanism. Instead of operating the panels having variable station names by coding cams, each panel may be associated with a number of keys bearing an origin label. Each key, in addition to performing the functions described with reference to the keys PPK1, PPK2, &c., connects a different combination of " coding " wires to the selecting relays. Specifications J.M,322 and 240,217 are. referred to.