Patent GB-466861-A (GB)
Title: Improvements in numerical time indicators
IPC: G04G9/10
Filed: 1935-12-07
Abstract: 466,861. Electric time indicators. SHIPTON, E. Dec. 7, 1935, No. 33970. [Class 139] Time-indicating apparatus in which the (hour and minute) numerals are formed from a field of lamps or strips by illuminating the latter in various combinations, comprises a rotary switch having contact banks and associated wipers which are advanced by a stepping magnet, the contacts being connected to illuminate various combinations of lamps according to the positions of the wipers, and means (cam 9 driven by a synchronous motor) for giving regular timed impulses to the stepping magnet. There are three indicators 4, 5, 6 for the units of minutes, tens of minutes, and units of hours respectively, each being of the eight bar type shown in Specification 317,271, [Class 118 (ii)], Figs. 6 and 7 : a fourth indicator 7 for the tens of hours has only two bars A and B. For the indicators 4, 5, 6 the eight illuminable bars A, B, ... H are wired through terminals a1, b1 .... h1, a2, b2 ... h2, a3, b3 ... h3 to the contacts of three rotary switches 1, 2, 3 of the type used for automatic telephony ; the eight wipers 11 ... 1<8>, or 21 ... 2<8>, or 31 ... 3<8> of each switch being advanced (vertically on the drawing) by a stepping magnet M1 or M2 or M3. Terminal ab4 of indicator 7 is wired as shown to the contacts of switch 3. Each magnet M1 ... M3 is so arranged that when energized it moves its pawl over a tooth of the ratchet wheel against spring pressure, whereby on de-energization of the magnet the spring and pawl advance the ratchet and the associated wipers. A mains-energized synchronous electric motor rotates a cam 9 to close contacts 8 once per minute ; the latter, through slowacting relay 10, close contacts 11 to energize magnet M1 over lines 12 and 13 and advance the wipers 1<1> .... 1<8>. If the latter rest on, say, the fourth horizontal row of contacts, wipers 11, 1<5>, 1', 1<8> are connected to terminals dl, e<1>, g<1>, M to light the lamps D, E, G, H in the shape of figure "4". In the units of minutes, if the wipers are on the "9" row of contacts and an impulse is sent by contacts 11, the circuit 12, 13 energizes the magnet M1 and a parallel circuit 12, 15, wiper 1<4>, contact "9," and. line 16 energizes the tens of minutes magnet M2. When contacts 11 open, the pawls of both magnets M1 and M2 advances the wipers 1<1> .... 1<8> and 2<1> .... 2<8>, one step. Similarly wiper 2<4> and the " 5 " contacts of switch 2, energize magnet M3 each time switch 2 passes from the " 5 " to " 6 " position. Indicator 7 for the tens of hours is wired to contacts 10, 11, 12 of wiper 3<4> in switch 3 so that lamps A and B of indicator 7 are lit for the hours 10, 11, 12 only. Alternatively for the eleventh hour, lamps A and B of indicator 6 could be lit for the tens denomination of the hours. The apparatus may include a stepdown transformer and rectifier giving 12 or 34 volts for the lamps and the whole arranged in a single casing with a plug connection for A.C. mains. The control unit may operate a number of numerical time indicators in various parts of a building. The switches may control relays which in turn control the current supplied to the lamps. The latter may be neon lamps of strip form.