Patent GB-739710-A (GB)
Title: Improved means for 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: 1952-03-28
Abstract: 739,710. Recording-apparatus. SOUTHERN UNITED TELEPHONE CABLES, Ltd. March 27. 1953 [March 28. 1952], No. 7996/52. Addition to 693,369. Classes 106 (1) and 106 (4). [Also in Group XVI] Record-printing apparatus for typing in sequence a series of readings of an instrument in the form of a line of figures in appropriate columns on a record sheet on a step-by-step moving carrier comprises, as in the parent case, a number of electrically-controlled type operating means, a position switch actuated by the carrier and a multi-point switch set for each leading, and, in addition, storage relays selectively operable by the multipoint switch to establish, in conjunction with the position switch, the appropriate typing circuits for a reading, and means for disconnecting the storage relays from the multi-point switch after the type operating circuits are established, whereby the multi-point switch can be set for one reading during the printing of the previous reading. A modified typewriter, whose types for printing the numerals 0 to 9 and the signs + and - can be actuated by magnets TAM, Fig. 4, in addition to manual operation by keys if required, is caused to print in each line of a record sheet first a serial number to identify a group of wires in a telephone cable to be tested and then eleven readings representing out-ofbalance and mutual capacities between different members of the group and between such members and other parts of the cable, the operations of counting, testing and printing being carried out automatically for a number of groups. Four quads SZ, SA, SB, SC, Fig. 2, of a cable are shown plugged into sockets of a connecting box 1 appropriately connected to a socket selector switch SS which comprises five levels 6-10 and associated wipers operated by a common driving shaft 11 through a step-bystep rotary drive 12 in quarter revolutions by a magnet MM. At each step the three wipers in each level 6-9 connect one quad to earth and two quads to eight leads 16, 17 and thence to a rotary test sequence switch TSS with twelve positions providing connections for eleven tests by an automatically balancing bridge 2 with associated pick-up coil 26, amplifier, balance indicator 28 and polarized relay AB as described in Specification 714,201, [Group XXXVI], and also providing connections to an insulation testing unit described in Specification 737,746, [Group XXXVI]. The fourth quad is disconnected awaiting replacement by another quad to be tested. The wipers of all levels of the test sequence switch TSS are operated by a common driving shaft 21 through a step-by-step rotary drive 18, 19, 20 advanced-by twelfths of revolutions by a magnet ML, when released, A multi-point switch MS and storage relays are associated with the adjustable differential condenser 27, Fig. 5, in the bridge 2, the switch MS comprising five banks of contacts MS1 to MS5 co-operating with wipers 30 driven through reduction gearing by the reversible motor driving the adjustable element 5 of the condenser 27 so that when a balance is reached and a catch 36 engages a notch 35 in a disc 34 to lock the condenser 27 and all banks of the switch MS against rotation, the latter remains set in positions representing a reading until an unlocking relay MK is energized to rock the catch 36 and free the condenser, and switch for the next test and setting. The wiper arms 30 of the banks MS1, MS2 make a complete revolution during unit variation of capacity of the condenser 27 where the unit is for instance 100 p.f. and the full range + or - 2,500 p.f. The banks MS1, MS2 '  for negative and positive readings respectively comprise ten fixed contacts 0-9 arranged in opposite senses, each pair of contacts of the same significant figure being connected to a storage relay A-J and corresponding to the " tens " figure in the reading. The next bank MS3 comprises a centre zero contact and 24 contacts each side linked in pairs to storage relays K-T and corresponding to the " hundreds " figure in the reading. The bank MS4 comprises a centre zero contact and a pair of contacts for each significant thousands figure 1 and 2 extending over the ranges 0 to 9, 10 to 19 and 20 to 24 of the bank MS3 and linked to storage relays U, V and W. The final bank MS5 has one " negative " and one " positive " contact linked to storage relays Y, Z. When the unlocking relay MK is deenergized at the end of a test, a circuit is completed through the wipers 30 in the various banks of switch MS to storage relays, appropriate to the reading, which close their own holding switches to establish new circuits through a slow-acting relay X which in due course opens the original circuits at switch X2 making the storage relays independent of the switch MS which is thus freed to take part in the next test while the energized storage relays close corresponding switches among switches A5 to Z5, Fig. 4, to prepare circuits to the appropriate magnets TAM for printing the reading in a column determined sequentially by the position switch PS. The relay X also closes at X1 a circuit through magnet ML and slugged relay A1 which then de-energizes ML to cause the wipers of switch TSS to advance. The position switch comprises two wipers PSW1, PSW2, Fig. 3, moved by the typewriter carriage over two banks of contacts PSB1, PSB2, Figs. 3, 4, covering 60 " spaces " divided into twelve sets each comprising, in PSB1, 5 contacts numbered 1 to 5 and in PSB2, a short and a long contact covering 1 and 4 spacas respectively. In PSB2 all the long contacts are joined and earthed through switch AJ1 or AA7 and each short contact is connected directly or through switching to one of the 12.contacts in level TSS11 whose wiper is permanently earthed. After a test has been initiated and switches AJ5 and AM1 closed, a motor driven cam 45 actuates an impulse switch IS, say 6 times per second, to send impulses through wiper PSW1 over successive contacts in PSB1 and through prepared switches A5-Z5 to space or type magnets TAM, the ensuing movements of the carriage advancing the wipers PSW1, PSW2 and the circuits being completed only so long as the wiper PSW2 is on an earthed contact, thus keeping the switches PS and TSS in step. The serial number of the group of wires under test is printed in the first column of five spaces by magnets TAM selected through a quad counter, Fig. 3, comprising 3 levels QCU, QCT, QCH, and the results of the corresponding tests are printed in the subsequent 11 columns by magnets TAM selected by the storage relays set by the switch MS after each test. Operation. When power is applied to the apparatus with all the parts in initial position as shown, a circuit is completed from earth via the wiper of level TSS11 of the test sequence switch, its contact 1, Fig. 2, switches KC2, KD1, Fig. 3, contact 1 of PSB2, wiper PSW2 and relay AN which operates, closing AM1 so that, provided the carriage is fully home to normal position bringing wiper PSW3 onto contact 46, relay MG operates to unlock switch KA1, Fig. 2. The operator then closes switches KA1 and KL1, one with each hand, and relay AZ closes switch AZ5 to initiate the insulation test. If the insulation is satisfactory, relay BF is excited to close switch BF1 and energize relay AJ, which closes its holding switch AJ2, opens AJ6 to disconnect the insulation testing relay AZ and open the homing circuit to the test sequence switch driving magnet ML, closes AJ1, Fig. 4, to earth the long contacts of PSB2 and the lead through AR1 to the capacity tester, multi-point switch and storage relays and closes AJ5, Fig. 3, to connect contact 1 of impulse switch IS to relay AM which operates as contact 2 of IS is earthed via PSW2. AM5 locks AM and AM1 connects PSW1 to contact 3 of IS so that impulses pass to space magnet MA, in turn via contact 1 of PSB1, contact 2 and the QCH level of the counter and contact 3 and the QCT level, then to magnet M1 to print the numeral 1 via contact 4 and the QCU level energizing relay AK which controls a magnet for advancing the QCU wiper to contact 2 ready for printing the numeral 2 in column 1 of the next line, and the fifth impulse passes to the space magnet MA via contact 5 of PSB1 advancing PSW1 and PSW2 to contacts 1 of column 2 to await the arrival of the earthed wiper of TSS11 on its contact 2 if not already there. Meanwhile, a circuit has been completed via AJ1, AR1, Fig. 4, ML2, Fig. 5, AU1, Fig. 2, to operate relay AT and AT6 has operated the unlocking magnet MK to free the condenser and multi-point switch and pass current via MK3, Fig. 5, to the condenser drive. When a balance is reached, relays AT and MK are released and the condenser and multi-point switch are locked during the setting of the reading into the storage relays after which they are unlocked, the wipers TSS are advanced by magnet ML while ML2 opens and closes to free various relays in the test circuitry, the next test begins and, provided wiper PSW1 has arrived on contact 1 of column 2 in bank PSB1 after completion of printing in column 1, the stored result of the first test is printed in column 2. If there is a significant thousand's figure in the reading, printing circuits are made from the first contact to either magnet M+ or M -, Fig. 4, selected by switch Z5 or Y5, from the second to either magnet M1 or M2 selected by switches V5 or W5, from the third to one of the magnets M0 to M9 selected'by the switches K5 to T5, from the fourth to one of M0 to M9 selected by A5 to J5 and from the fifth to space magnet MA. A relay A0 in the circuit through the fourth contact opens a switch A01 to interrupt the holding circuits to the storage relays and relay X, thus releasing them for storing the next reading. The circuitry is so arranged that if the first significant figure is in the hundred's place the sign is shifted to the thousand's place and if the first significant figure is in the ten's place the sign is shifted to the hundred's place as