Patent GB-836041-A (GB)
Title: Method and apparatus for finding faults in a plurality of conductors
IPC: G01R31/02
Filed: 1957-02-18
Abstract: 836,041. Electric tests. NEILL, O. S. Feb. 18, 1957 [March 19, 1956], No. 5359/57. Class 37. The connections between input and output ends of a device are tested by apparatus under the control of a succession of record bearing members, such as punched cards, each of which selects one terminal at the input and one at the output, applies various tests to these terminals and indicates whether the correct circuit has been established in the apparatus and, if desired, its condition. General operation (Fig. 14) test signal source A feeds a signal voltage to the ends of a conductor B under test. The conductor may be connected to any of the terminals C of the connectors D placed selectively in circuit by devices E and F controlling the connections at the output and input ends respectively. The terminal selection is made by a sensing device G which controls selecting devices E, F, in response to information entered on a punched card H. Sensing device B forms part of the return circuit of the source A and is stopped if the circuit is incomplete or held in any of the tests applied to it. Indicating means are connected to each terminal to show failure of a particular connection or circuit. Elementary circuit (Fig. 3) shows a test on a single wire 60 terminating at connectors 61 and 62 and having applied to it a continuity test and a current carrying capacity test. Motor 63 is set in operation by manual switch 65 and drives through a magnetically-operated clutch 67 a sensing device 69, pulse generating cam 71, holding voltage cam 72, and test cams 73, 74. The sensing drum connects pulses provided by pulsing cam 71 to brushes 76, 77 when they enter holes in a card, punched to indicate the terminal to be selected at the input and output ends. The instant of location of these pulses operate relays 80, 81 at the input and output ends respectively to select the appropriate terminals (Fig. 6) at connectors 61, 62. These relays are locked by holding cams 72 and the further cams 73, 74 apply the two tests in succession to the selected circuit. If the circuit has been correctly established lamps 88, 89 are operated and the test current is enabled to maintain clutch 67 operated, Fig. 4, see below, so that motor 63 continues to operate, the next test card is in circuit and a further pair of terminals is examined. Terminal selecting device (Figs. 6 and 7). An arrangement shown in Fig. 6 replaces each of relays 80, 81 in the simplified arrangement of Fig. 13. Fig. 7 shows the selecting card used in which apertures 138, 139 represent the selection of terminal A of the output and apertures 128, 129 of terminal K at the input. Motor 65 drives in addition to the cams already detailed, a series of cams 127(1) . . . 127(12) which sequentially close the circuits of associated relays 110(1) ... 110(12). If at the instant of closure of the circuit by the cam a card aperture is sensed, a pulse from cam 71 operates the appropriate relay. Each letter is indicated by a two-part code which involves selection of one of the first three relays 110(1) ... 110(3) with subsequent selection of one of 110(9) ... 110(12). Thus to select terminal K the punched card first selects relay 110(2) which prepares a circuit for the second of three banks of series controlled switches associated with relays 110(4) . . . 110(12). The card then selects relay 110(5) which interrupts the circuit of the second bank at terminal K to apply the test to the line connected to that terminal. Cams 73, 74 then apply the appropriate test over line 106. The testing current operates lamp 137 indicating which terminal has been selected. The clutch control device (Fig. 4) comprises a clutch cam 92 driven by motor 63 to close the circuit of clutch-operating magnet 68 immediately after the application of the first test to the selected terminal by cam 73. Relay 94 operates to prepare the circuit of relay 98. If the test is received from line 90 (c.#. Fig. 3) relay 98 prevents energization of a relay 100. If not, relay 100 operates and breaks the circuit of clutch-operating magnet 68 which can only be restored by operating switch 103. Thus the stopping of the machine indicates that, for some reason, the return signal has not been received. Multiple connector-multiple group system (Fig. 8). Fig. 8 shows the selection of a particular terminal of a particular group, for example lower case or upper case in a particular one of a set of connectors. In this arrangement the terminals are divided among ten connectors each of which contain ten groups of ten terminals. The record card must carry information for selecting the terminal, group, and connector. The test signal from line 140 is distributed by a terminal selector 142 to a selected terminal line 144. A group selector 145 energized from group pulse line 146 feeds a holding voltage from line 147 to one of ten banks of relays each relay bank having ten terminal switches closed in unison. When the terminal group bank 149 is energized ten individual terminal connectors are closed, each of which connects a terminal 144 to a group bank relay switch 150 to the line 151. The connector is selected by a connector pulse in line 152 to operate connection selector 153 supplying a holding voltage to a bank of connection relays 158 serving all the terminals for the selected connector. Each bank of collector relays comprises 100 relay switches to be closed upon energization of a selected relay bank determined by the connector selector 153. Terminal light 158 for each selected terminal will be energized by the test signal to indicate the selected terminal. Group lights 159 and connector lights 160 are also provided. The cable testing-machine (shown in Fig. 12) uses an information card of the type shown in Fig. 10, wherein columns 175, 176 select the terminal 179, 180 the connector and 177, 178 the upper or lower case of the alphabet. Assume that the information carrier K calls for the selection at the input of terminal K in the upper case alphabet of the fourth connector 236, and at the output of lower case k of the output connectors. Card 173 will be punched at 302, 303 in the information column 176 to close the K alphabet terminals switch as previously described with reference to Fig. 6. A double pulse is sensed by brush 255 energizing group selecting relay 260, closing relay switch 259 and passing the selecting signal through line 248 for selection by the terminal selecting device 247. The K relay switch 249 corresponding to 113/5 of Fig. 6 will be selected and maintained closed by the holding voltage for cam-operated switch 226. Relays 260 and 263 are then operated by an upper case terminal pulse which also lights the appropriate lamp of pair 265, 266 to indicate which alphabet has been selected. The test signal for line 235 will connect through switch 244 to all upper case K relay switches of the series of upper case relay banks 240. The selection of the fourth connector is made by punching card 173 in the connector selecting column 180 at 196, 197. The connector selecting means is energized by the connector pulses and is of the form shown in Fig. 6. The selector applies a holding voltage to the selected connector relay banks 239, 240. Only the upper case bank 240 will receive the signal so that the testing will be communicated to the K terminal of connector 236. A similar process of selection connects a corresponding terminal in the lower case alphabet for the return path except that relays 281, 275 are not operated. Correct receipt of the test signals maintain the magnet clutch operated.