Patent GB-339254-A (GB)
Abstract: 339,254. Automatic Telephone Manufacturing Co., Ltd., and Simpson, L. M. Aug. 27, 1929. Totalizators.-In an odds indicator the ratio between the total on and against the horse is calculated electrically by a Wheatstone's Bridge in which the two ratio arms include resistances proportional to the grand and an individual horse total respectively ; the third arm contains a fixed resistance, while the fourth arm has a resistance which represents the odds and is varied to maintain the balance, of the circuit by a relay connected across the bridge in the usual manner. Figs. 1 and 2 show the apparatus as used with the totalizator described in Specification 331,500. the Wipers 1, 2, 3, and 4 of the switch HAM, Fig. 1, are driven in synchronism with the corresponding wipers of an individual horse counting switch, and the wipers 21, 31, 41 and 51 of the auxiliary switches PC. TPC. HPC. ThPC are driven by means of the corresponding relays A - - Dand driving magnets PM, TPM, HPM, ThPM, in synchronism with the corresponding wipers of the counting switches 26, 36, 46, 56 of the pool total counting switch TAM. One side of the " Bridge " runs from earth, through wipers 4, 3, 2, 1, conductor 10, wipers 22, 32, 42, 52 and resistance 5 to positive. The other side runs from earth, through a resistance 6, wiper 11, resistance 7, conductor 8, to resistance 5 which is inserted outside of the bridge as a current limiting device. A unit, 10 ohms, is taken to represent ú1 so that when the wipers 4 - - 1 advance one step, additional resistances of 10,000, 1000, 100, 10 ohms respectively are inserted, and similarly when the switch TAM operates, the wipers 52, 42, 32, 22 insert corresponding resistances. Operation. If the betting is such that ú400, say, has been wagered, of which ú100 is on the horse corresponding to the switch HAM. the wiper 3 is rotated over one contact to insert 1000 ohms in its circuit, while the series of wipers 41, 42 of the switch HPC are advanced over four contacts the wiper 42 inserting 4000 ohms in its circuit. The balance of the " Bridge " is now destroyed, current flowing through the control relay CR. This closes at the contact cr1 the circuit of a driving magnet CM which rotates the series of wipers 11 - - 16 of the compensating switch CS until the wipers 11, 12 have inserted sufficient resistance in the fourth arm to again restore the balance. The fixed resistances 6, 7 are 100 ohms each, and the wipers 11, 12 accordingly advance three steps (each step inserting 100 ohms), the 300 ohms thus inserted in series with the resistance 7 giving a ratio 4 : 1. The balance restored, the relay CR is de-energized, stopping the driving magnet CM. The wipers 15, 16 having rotated three steps will indicate odds of 3 : 1 on the units indicator UI which with the tens indicator TI operated by wipers 13, 14 is of the monogram lamp type controlled as described in Specification 331,500. If the odds increase, the wipers 11, 12 will again advance until balance is secured, while if the odds decrease, causing a reverse current to flow through the relay CR, these wipers will have to rotate nearly a whole revolution before balance is again restored, the magnet CM operating to drive the wipers 11, 16 in one direction only. The compensating switch may be arranged to operate in either direction. As the tens leads are multiplied only five times round the banks 13 and 14 odds greater than 50: 1 cannot be indicated, in which case the compensating switch rotates continuously. It could be brought to rest in the limiting position by the use of a polarized relay with the unidirectional switch CM. The extra wipers and banks 23, 25, 33, 35 &c. are for use with odds indicators for the remaining horses, 80 runners being accommodated. Specifications 331,516 and 338,897 are referred to in the Provisional Specification.