Patent GB-739712-A (GB)
Title: Improved means for automatically obtaining and recording the readings of an instrument, or group of instruments, suitable for the testing of the circuits of electric communication cables
Inventor: MEADOWS STANLEY GEORGE
IPC: G01R13/00
Filed: 1952-05-23
Abstract: 739,712. Recording apparatus. SOUTHERN UNITED TELEPHONE CABLES, Ltd. May 22, 1953 [May 23, 1952], No. 13147/52. Class 106 (4). [Also in Group XXXVI] Apparatus for automatically obtaining the reading of an instrument or a group of instruments and for printing the readings as columns of figures on a record sheet, comprises a number of type-operating electromagnets in combination with a carrier for the record sheet and means for producing relative step-by-step movement between the carrier and a printing position, a set of relays arranged to act in sequence and in steps to establish a circuit or circuits for the electromagnets appropriate for each reading, a position switch actuated by the relative step-by-step movement of the carrier to establish circuits determined by the position of the carrier, and the circuits so established at each relay setting and associated position of the position switch coacting to actuate the appropriate electromagnets to print a part of the reading. A modified typewriter, whose types for printing the numerals 0 to 9, signs + and - and " spaces " can be actuated by magnets M0 to MS2, Fig. 5, in addition to manual operation by keys if required, is caused to print on each line of a record sheet in the typewriter carriage the result of two capacity tests and two resistance tests automatically carried out in sequence on the quads of a telephone cable. Four quads are connected at one end to sockets ST1 to 4, Fig. 2, and at their other ends to sockets SB1 to 4. The sockets ST1 to 4 are connected to bus-bars X1 to 4, Y1, 2 through switches controlled by relays CA to D, Fig. 3, selected at the first level RLS1 by an automatically operated multi-level selector switch whose wiper arms are mechanically ganged to move in unison. The bus-bars are also connected to an insulation tester IS, a capacity bridge network and a resistance bridge network by switches controlled by relays CE to I selected at the second level RLS2 of the selector switch. At appropriate stages in the sequence of operations, preparations are made for the capacity and resistance tests by the actuation of switches controlled by relay CJ and CK, CL, CLS, selected at the third level RLS3 of the selector switch, the preparations including switching a voltage comparator VC into the appropriate bridge and selecting A.C. or D.C. current. Each of the capacity and resistance tests is initiated at level RLS4 through relay CM closing switch CM2, Fig. 2, to energize a three-position sensitive relay BA in the voltage comparator VC. An initial unbalanced condition causes switch BA1 to energize " negative " or " positive " relay BB or BC and by energizing relay BE, Fig. 4, or not to select type magnet M- or M+, Fig. 5. Switch BA1 also energizes relay BH to close switch BH1, Fig. 4, while BB3 or BC3 energizes BD and BD1, energizes BI to close BI1, thus completing a circuit to a first bridge adjusting relay A which adds a unit of 10 p.f. at A3, Fig. 2, in the capacity bridge, or, at A4 in the resistance bridge, makes a unit change of 0.1 per cent. The bridge adjusting relays comprise four sets : (a) relays A to I each adapted to add or subtract one unit in the bridge circuit adjustment; (b) relays J, JA to D which effect the transference from the units group to the tens group and from the tens group to the hundred relay, clearing all relays of the lower denomination at each transfer ; (c) relays K to S each representing 10; (d) relay T representing 100. Each relay excites its own holding circuit and the next relay, the process continuing automatically until, when balance is attained, the voltage comparator VC releases relay BA and BH1 opens to arrest further bridge adjustment, the established value being held until recorded. If balance is not achieved before the maximum value that can be measured is reached, relays Sand T will be energized at the same time and prepare at S2, T2, a circuit to an excess value relay JE which will be energized when J1 closes at the next tens transfer, JB6 being off-normal and JE2, JE3 will break the earth circuits to bring the apparatus to rest, to be restored by manually opening the holding switch KO. Operation is initiated by switching on various current and voltage supplies so that, provided the position switch wiper PSW, Fig. 5, which moves with the carriage, is on the first of its 21 contacts, an electromagnetic lock releases keys for the operator at each end of the cable to depress when lamps LT1, LB1 indicate the quads are correct in the sockets. Depression of the keys energizes relay DA, Fig. 3, and switch DA2, Fig. 2, initiates the insulation test and if the test is satisfactory relay DE closes switch DE1 to energize relay DF and release DA. Typewriter relay CQ, Fig. 5, is then energized and CQ2 earths wiper PSW energizing relay CU and stepping magnet TS for the rotary switch RLS. CU6 closes causing a space to be printed and wiper PSW to move to contact 2. At each movement of the typewriter an interrupter switch IR opens and closes. Thus relay CQ de-energizes opening CQ2 to disconnect PSW from earth. Magnet TS releases to advance the rotary switch to second position. This releases DF, opens DF1 and releases CU. The capacity bridge is brought into circuit by relay CF from level RLS2 and balancing is initiated by relay CM from level RLS4. Switch BH1 closes in the operating circuit of the bridge adjusting relays which select appropriate type-actuating magnets and hold them at balance when BH1 opens. BB7 and BC6 now being normal and BD holding BD6 closed, relay CQ is re-energized to close CQ2. A printing circuit is thus completed through wiper PSW and contact 2 of the position switch to the selected type-actuating magnet. The typewriter is moved automatically step-by-step by the usual mechanism into the positions corresponding to position switch contacts 3, 4, 5 and 6, operating a type magnet in each position. In the sixth position, relay CU is again energized since BI2 is closed by relay BI held at BD1 by relay BD. Relay CM is released by CU4, the bridge adjusting relays are released by CU1 and spacing magnet is operated by CU6. Meanwhile, mag. net TS steps the rotary switch tc third position to energize relay CG from level RLS2. With the position switch on contact 7, the next test proceeds and operations con tinue until all the tests have beer made and recorded and the wiper PSW is on the final contact 21. Again a space is printed by magnet MS2 and the magnet TS steps the rotary switch to its sixth position while the carriage is returned by hand or automatically to initial position where the contact between wiper PSW and contact 1 will allow testing to begin on the next quad connected by relay CB. This will be repeated with relays CC, CD connecting the remaining quads in turn until the wiper PSW engages the contact 21 for the fourth time and the rotary switch moves to its 21st position to energize a relay CS from the level RLS1 for homing the rotary switch to first position. When the operators have connected new quads to the sockets the complete cycle of tests is repeated. The type operated to print in the 2nd to 5th columns of each record are determined by the co-operation of the position switch and bridge adjusting relays as follows : (a) contacts 5, 10, 15 and 20 of the position switch are normally connected to print any value from 0-9 according to the setting of the units relay switches A6-I6 ; (b) contacts 4, 9, 14 and 19 are normally connected to print a sign dependent upon the position of switch BE6. When the record contains two significant figures, the tens relay K has moved switch K3 to connect these contacts to the appropriate magnet M1-M9 as selected by the tens relay switches L3-R3 and S6. If relay T operates and no tens relay then magnet MO is connected over switches T8, K6 ; (c) contacts 3, 8, 13 and 18 are normally connected over T6 and K8 to space magnet MS1. With two significant figures and K8 off normal, a sign magnet is connected and with three significant figures T6 connects M1 ; (d) contacts 2, 7, 12 and 17 are normally connected to MS1 by T5, but with three significant figures and T5 off normal they are connected to a sign magnet. If a bridge is balanced at the beginning of a test, relay BA does not operate, but, after a short interval from the closing of switch CM5, a slugged relay BF, Fig. 4, operates and adds a small capacity, or resistance to one arm of the appropriate bridge at BF3 or BF4 and by energizing relay BG through BF1 opens the bridge-adjusting relay circuit at BG2 so that as switch BA1 moves to positive position to operate relays BH and BC, the bridges will not be adjusted but relay BD will operate and disconnect relay BF at BD3 so that balance is resumed while the closing of switch BD6 will operate the typewriter relay CQ and cause the result +0 to be printed. Arrangements may be made for eliminating the first three tests or the last two tests through manual switches S/S and CU in conjunction with level RLS5 of the rotary switch, the typewriter stepping through corresponding positions without printing and the test initiating functions of the relay CM being inhibited. In order to check the operation of the apparatus, a switch KS1 is closed manually to operate a relay CP which by closing a switch group CP1-CP6 connects to the bus-bars X1-Y2 a circuit network STD simulating a standard cable. Specifications 737,743 and 737,746, [both in Group XXXVI], are referred to.