Patent GB-1214147-A (GB)
Title: Meter reading unit
Inventor: DRANSFIELD DESMOND
IPC: G06M1/27
Filed: 1966-12-16
Abstract: 1214147 Indicators for meters UNITED GAS INDUSTRIES Ltd 4 Dec 1969 [16 Dec 1966] 55148/67 Divided out of 1213125 Headings G4D and D6Y A unit for indicating the reading of a meter of the kind having a selector switch for each digit of the reading with connections from the wiper and ten contacts of each selector switch, has means adapted to be coupled to these connections and means for causing an indicator to indicate the digit set up on the corresponding meter switch. Corresponding output leads from the switches are connected in common to a terminal block outside the building so as to be accessible to the reading unit. The switch wipers are also connected separately to the terminal block. The meter reader has a unit 37, Fig. 2, plugging into the terminal block. A potential divider 63 is energized by battery 61, the voltage of which is stabilized at 51. The ten terminals 21-30 are connected to the tappings of the potentiometer, a voltage being picked off by the wiper of each switch according to its position and presented at the terminals 31-34. Switch 56 in its unoperated position connects these terminals to corresponding voltmeters 57-60 which indicate the digital values in the four decades. When switch 56 is operated the full voltage is applied across the voltmeters for calibration purposes. In another form four stepping switches are connected to the ten output leads. When the unit is plugged in a relay associated with the first stepping switch is energized and a circuit completed to the wiper of the highest-decade switch of the meter. The stepping switch is then driven by a pulse generator until the wiper finds the lead connected to the corresponding meter switch. The relay then falls out and a second relay is energized to connect the next decade switch and step the next stepping switch. The process is repeated until all the stepping switches correspond with the decode switches. Numeral wheels rotating with the stepping switches indicate the digit values of each decode. Means are provided for repeating the reading when the last digit is "0" to avoid errors due to higher denomination values changing while lower values are being read, for example if 2999 changes to 3000 after the first digit has been read a value of 2000 will be obtained. The second reading corrects this. In the form of Fig. 4 the meter unit contains a resistor chain 141 so that each decade value is represented only by a resistance value presented at the corresponding terminal 160-163. A selector switch 171 connects these terminals in turn to a bridge circuit of which the other arm 179 is changed to give a balance. While the bridge is unbalanced a signal is applied to a pulse generator 183 causing a corresponding counter 186-189 (selected by switch 195) to step the associated wiper 200-203 (selected by switch 209). When a balance is reached the switches 171, 195, 209 which are all ganged together, step to the next position and the next digit is balanced. The four digits are thereby set up in the four counters 186-189 and associated numeral wheels indicate the digits.