Patent GB-535891-A (GB)
IPC: G06F7/44
Abstract: 535,891. Typewriters &c. NATIONAL CASH REGISTER CO. July 19, 1939, No. 20946. Convention date, July 21, 1938. [Class 100 (iv)] [Also in Group XIX] An electrical calculating machine particularly for use in billing, posting and classification work comprises a number of registers each including a plurality of electrical digit relays and digit representing contacts actuated thereby, one or more travelling record material carriages to record the digits successively in accordance with the numerical values set up and with the results of a calculation, and means automatically to tabulate the carriage in dependence upon the values and results. The machine, in the form shown for making out an invoice, consists of three essential units ; a typewriter on which the invoice is made out with a digit and control keyboard, a second typewriter to carry the ledger card with the customer's old balance, and an electrical calculating unit or assembly of electromagnetic relays and interconnected leads which automatically perform various kinds of calculations such as addition, subtraction and multiplication under control of the keys. The electrical connections are also arranged to permit the transmission and storage of results in various registers for the purpose of taking totals, sub-totals, classification totals, balances, and net amounts involving discounts. In operation the text of the invoice, Fig. 83 (not shown), consisting of the name, address and necessary code or other information is recorded by operation of the type keys. The first factor is then introduced, by depression of the numeral keys, into a primary register and upon depression of an appropriate control key it is automatically recorded on the invoice. The second factor is similarly entered and recorded and the control key is again depressed to initiate the computing operation. Other items are entered and recorded in succession. The invoice may be divided into sub-divisions, pertaining to various classifications, and at the end of each sub-division the sub-total key is depressed to print the sub-total. Discount is computed on depression of the discount key and automatically subtracted, by complementary addition, to give the net total. When the net grand total has been computed the balance key and total key are depressed to initiate a machine operation whereby the net total is printed on the ledger card in the second typewriter and is added to or subtracted from the old balance initially set up on the ledger card and the new balance is computed and printed. Calculating unit.-The relays and registering devices are similar to those described in Specifications 211,137 and 314,026, [both in Class 106 (i)]. The relays are of the multi-contact type with free and/or locking armatures. The registering devices, Figs. 1A, 1B, 2A and 2B, comprise locking relays LKI ... LKO with actuating and control relays W, U, X1, V2, V1 and X2. The armatures of the LK relays cooperate with hooks K1, Fig. 4, pivoted on denominational locking bars Ml, M2 &c. connected by insulating links N1, N2 &c. to thrust bars MM1, MM2 &c. The thrust bars carry levers O1, 02 &c. with co-operating detents R1, R2 &c. and pins Sl, S2 &c. T1, T2 &c. T'2, T'3 &c. so that when a thrust bar is operated the next higher bar is prepared for operation. The alternate operation is controlled by the relays V1, V2 after the register has been prepared by the release relay U which sets the lowest denomination lever O1. The register is cleared by the operation of the relay W. The thrust bars are provided with projections on the underside to co-operate with the armatures of the relays U, X1 and X2 to hold their armatures away from their fixed contacts. Keyboard construction.-The entry of an item is effected by depression of numeral keys KF, Figs. 28 and 30. Each key comprises a body part or lever suspended on a rounded edge KC and formed with a slot which receives a spring and roller on a pair of arms KL that carries a second roller KN for co-operation with spring contacts KQ on a bus-bar KP. The arms KL carry a pawl KS which operates to impart a snap action to close the contacts KQ, KW. The keyboard is formed with a ball race containing balls and rollers to prevent depression of more than one key at a time. A lock, full stroke, and release means for the keys comprises a notched part on the key lever and a latch KHH pivoted on a bail KJJ. Release of the keys is effected by the armature KNN of a release relay acting upon lugs on the bail KJJ. The relay remains operative until the key circuit is broken so that it is not possible to depress a new key or to operate a released key a second time. Recording apparatus.-The preferred form of recorder is a standard automatic typewriter as shown in Fig. 32. The apparatus has a constantly running shaft TS driven by an electric motor and depression of a key manually or by energizing one of a number of electromagnets TPM pulls down a pawl TP which, by engaging splines on the shaft TS, is carried forward to raise its associated type bar TB. Letter-spacing; tabulating stops.-The letterspacing mechanism comprises the usual escapement wheel TPP and spring-controlled band TD<SP>1</SP>. For tabulating purposes stops TA, Figs. 32, 36 and 40, are provided for co-operation with adjustable carriage stops TF, TF' and TF". The tabulator stops TA are loosely mounted on a shaft TO and are formed'with triangular slots through which passes a rod TJ supported in a slidable block TM embracing the stops and an arm TT secured to the shaft TO. Raising a tabulating stop by energizing a tabulating magnet TTM rocks the shaft TO to free the carriage escapement mechanism. During the tabulating movement the block TM is thrust sideways to signal the end of the tabulating movement by opening a switch. The action of the magnets TTM is aided by a magnet THM energized on the initial movement of the shaft TO by the closure of a switch THS. To reduce the current holding the armatures of the magnets TTM a relief switch TMS, actuated by the shaft TO, is provided to introduce a resistance into the circuit. To change certain of the tabulating stops at will the stops TF' and TF<SP>11</SP> are connected to arms TEM and TEN rotatable with and slidable along a shaft TEH operatively connected to an arm TEL loose on the shaft TO. Energization of a magnet TSO throws out all stops TF' and throws in stop TF". These stops are changed when the magnet TS1 is energized. This principle may be extended by the use of additional magnets and auxiliary shafts TEH. Case-shift mechanism.-A cam clutch dish TAN, Fig. 47, can be coupled to the splined shaft TS on depression of a shift key TBE or the energization of magnet TSK to operate an associated linkage TAW, TAY, TBC to raise the carriage frame. Carriage return mechanism; line spacing.- The carriage return is effected by depression of a return key TCK or energization of magnet TCR, Fig. 51, which lowers the left-hand end of a horizontal bar TCF and frees it from a fixed stop TCG. Upon release the bar is displaced by its connection with a spring-controlled arm TCE, TCA, and couples a dog clutch TBS, Fig. 55, to the shaft TS to wind up the belt TBX and return the carriage. The carriage takes along a stop TCP until it strikes an abutment on the bar TCF to arrest the movement. To avoid operation of the return mechanism when the carriage is already in its right-hand position, the stop TCP depresses the free end of a lever TCQ and operates a lever TCW to prevent depression of the return key. Line spacing is effected during the return movement of the carriage by the action of a link TCY, Fig. 53, attached to the belt TBX and a linkage which presses on a thrust bar TDG to cause a pawl TDH to feed a ratchet wheel TDK, Fig. 56, on the platen. One of the levers of the linkage has a projecting handle TDC for manual operation. Ink-ribbon mechanism.-A thrust bar TDV, Figs. 32 and 57, actuated by the type bars rocks a lever TDX and through a link TDY pulls on a hanging arm TEB to rock its shaft. This shaft carries an arm TEC connected by a link TRC to a rockable arm TRD which raises the arm TRE and ribbon holder to operative position. To shift the ribbon a magnet TRS is energized to raise a bar TEA and lift the link TDY so that when it is operated it rocks the arms TEC, TRD through a greater angle to raise the ribbon holder a greater distance. Circuit arrangements and operation.-On depression of the item keys entry is effected in the primary register from left to right and after the entry an operation or control key, e.g. decimal, add, multiply &c. is depressed to initiate the typewriter tabulating movement and the successive control of timing relays which start the printing operation digit by digit through circuits which include the locked armatures of the primary register. The rate of sending out impulses with the rate of actual printing is synchronized by means of a wheel-operated switch which governs the timing relays. To perform a computation the number stored in the primary register is transmitted to a secondary register ; this is effected through reversing relays so as to present the number to the addition relays of the secondary register in their proper denominational order. In the process the number may be added to or subtracted from a number already stored in the secondary register by depression of an add key or an-add key and subtract key. The circuits include transfer or non-transfer indicating or preparing relays in association with transfer relays and subtraction relays. The contacts of the register relays are connected with the wires in the outgoing cables so that they represent numbers equal to the unit digit of the sum of the number of the incoming lead and the number of the relay, subtraction being effected by the addition of the complement. Clearing of the primary register to correct an error is initiated by depression of a clearing key ; in the ca