Patent GB-601122-A (GB)
Title: Improvements in or relating to calculating apparatus
IPC: H03K3/78
Filed: 1945-02-15
Abstract: 601,122. Calculating-apparatus. NATIONAL CASH REGISTER CO. Feb. 15, 1945, No. 3890. Convention date, Dec. 27, 1943. [Class 106 (i)] A multiplying machine comprises an impulse generator which at each cycle of operation produces in each denomination a number of electrical impulses equal to the corresponding digit of the multiplicand, a multiplier unit for causing the generator to perform for each multiplier digit a number of cycles equal to that digit, and a distributer for switching the generated impulses to the appropriate denominations of a totalizer. General operation. The multiplicand is set by depressing keys controlling an impulse generator comprising a number of banks of gas-filled electric-discharge tubes, one bank for each denomination. When a " start " key is depressed, the banks operate from the highest downwards and from each bank is emitted a number of impulses corresponding to the key depressed in that bank. The impulses are passed to a totalizer through a denominational distributer which may change their denominational value. The operation of the impulse generator is repeated a number of times determined by the multiplier keys depressed in a multiplier unit. If 1087 is to be multiplied by 347, in the first phase of the calculation, 1, ,8 and 7, impulses are originated in the thousands, tens and units denominations respectively of the impulse generator and are routed through the denominational distributer to the hundred thousands, thousands and hundreds denominations of the totalizer to enter 1,087,000. This operation is automatically repeated three times. The second phase then follows, the 1, 8 and 7 impulses from the generator being routed to the ten thousands, hundreds and tens totalizer denominations respectively, this occurring four times in succession. This is followed by the third phase, during which the 1, 8 and 7 impulses are routed to the thousands, tens and units denominations of the totalizer respectively, this occurring seven times. The totalizer comprises a number of denominational banks of gas-filled electric-discharge. tubes and at the end of the multiplication the product is found by observing or by determining, e.g., by the means disclosed in Specification 593,682, which tubes are firing. The apparatus can also be arranged for adding and subtracting as described below. Impulse generator. This comprises a number of similar banks, one for each denomination and each having eleven gas-filled electricdischarge tubes. The units bank is shown in Fig. 13. The banks operate from the highest downwards, each emitting on its respective output conductor 108 a number of impulses corresponding to, the digit key 89 depressed in that bank followed by a '' T " impulse which in a denomination other than the units initiates operation of the next lower denomination and in the units denomination is used to control the next step in the calculation. If no key in a bank has been depressed, earth potential is applied through a switch 71 to the grid of a gas-filled discharge tube D to raise the grid potential above the value at which it is normally maintained by a connection through a resistance 99 to a negative-potential line 48, the tube thus being primed to fire upon the arrival of an impulse at an input terminal 78 The cathode of tube D is connected to the grid of a tube T which thus fires upon the firing of tube D to give a " T " impulse at a controlling terminal 115. In higher denominations than the units, the terminal equivalent to 115 is connected to the input terminal 78 of the next lower denomination to set that denomination in operation. If a numeral key has been depressed, a bar 72 has been shifted to the left to change, the switch 71 to apply earth potential to the grid of the " 1 " tube to prime this tube so that, upon the arrival at the input terminal 78 of a starting impulse from the next higher T tube, the 1 tube fires. The potential rise in the cathode of this tube generates an impulse in a line 60 connected to the output terminal 108 and also, through a switch 55, is applied to the grid of the 2 tube which thereupon fires to give another impulse to the output terminal 108 and to fire the 3 tube. Upon the firing of the 2 tube, the initial anode current is great enough to cause a sufficient fall in the anode potential line to extinguish the 1 tube. When eventually the tube corresponding to the depresssed numeral key fires, the cathode impulse is switched to the grid of the D tube, instead of the next ordinary tube, since the depressed key breaks the grid connection 55 and connects the cathode to a common line connected to the grid of the D tube, which thus fires to fire the T tube. Totalizer. This comprises a number, of denominational banks similar to the units bank, Fig. 1, and each having ten gas-filled electricdischarge tubes related to the digits 0 ... 9 and a transfer tube T. A digit standing on the totalizer is represented by the corresponding tube, e.g., 8, being in a fired or conducting state, the cathode circuit being connected from points 1320, 1350 and a switch 1360 to the grid of the 9 tube to prime this whereby, upon the arrival of the next impulse at input terminal 1600, the 9 tube fires, the 8 tube being extinguished and the 0 tube and transfer tube primed. The totalizer is arranged for subtraction by pushing the switch 1430 to the right to change the cathode-grid connections so that the 8 tube now primes the 7 tube, the 0 tube, the 9 and transfer tubes, and so on. Denominational distributer. This comprises a series of gas-filled electric-discharge tubes, Fig. 19, arranged in four stages I ... IV, viz. units, tens, hundreds, thousands. During a multiplication, each stage is primed in turn. The priming of stage IV is accomplished by the application of a priming voltage to a terminal 2260 connected to the grids of the stage IV tubes 1840, 2200, 2220, 2240, this voltage being obtained by the firing of a stage IV control tube 2050, Fig. 20, situated in a stage control unit. Impulses from the units denomination of the impulse generator arrive at input terminal 108 and are applied to the grids of a row of units receiving tubes 1810, 1820, 1830, 1840. Of these, only the last 1840 is primed and is the only one to fire. An impulse is thus given to the thousands output terminal 1650 connected to the thousands denomination. of the totalizer and the fired tube 1840 is extinguished. Impulses from the tens denomination of the generator arrive at the input terminal 109, are applied to the tens-receiving tubes 2100, 2160, 2190, 2200, firing the last 2200, this being the only one of the row which is primed, to give an impulse to the tenthousands output terminal 1660. Hundreds and thousands generator impulses reaching input terminals 110, 111 fire tubes 2220, 2240 respectively to give hundred thousands and. millions impulses at output terminals 1670, 1680. - When all this has been repeated a number of times controlled by the thousands multiplier digit as described below the stage IV control tube 2050, Fig. 20, is extinguished and the stage III control tube 2060 fired to provide potential at a terminal 2250 to prime the stage III distributer tubes 1830, 2190, 2210, 2230. A thousands impulse arriving from the generator at input terminal 111 will now fire the stage III tube 2230 to produce an impulse at the hundred thousands output terminal 1670, other incoming impulses likewise producing output impulses of one hundred times greater in denominational value. When this phase of the calculation is completed, the stage III control tube 2060 is extinguished and the stage II control tube 2070 fired to prime the stage II distributer tubes 1820, 2160, 2170, 2180 so that arriving generator impulses originate totalizer-actuating impulses of ten times the generator impulse denominational value. Stage I tubes 1810, 2100, 2110, 2120, 2130, 2140 are then primed by stage I control tube 1920. During this last phase generator impulses produce totalizer-actuating impulses unchanged in denominational value. Multiplier unit. Stage control unit. Various control circuits. The multiplier is set by keys in a multiplier unit (called a tally impulse generator) consisting of a number of denominational banks of gas-filled electric discharge tubes, the banks all being similar to the thousands bank, Fig. 9. In every denomination in which a key is depressed, a detent bar 301 is displaced to close a switch 311, Fig. 20. To effect multiplication, a multiplying key 290, Fig. 20, is depressed, and then a start key 260. This latter causes the firing of a gas-filled electric-discharge priming tube 263, the resulting rise in cathode potential passing via depressed multiplier key 290 and the highest operated detent bar switch 311 to prime the stage control tube, e.g. tube 2050, stage IV, corresponding to the highest active multiplier denomination. The start key also causes the firing of a start tube 342, the cathode impulse from which is impressed on all the stage control tubes and fires the primed one 2050. This latter fires a companion tube 277 to produce an impulse at a point 375 connected to the thousands multiplier unit to fire the 1 tube thereof. The resulting cathode impulse passes from output terminal 253 to the grid of a relay tube 230, Fig. 22, which causes the firing of a control tube 200 to emit an impulse on a terminal 84 which sets off the thousands bank of the impulse generator. The other denominations of this generator then operate in turn. Impulses equal in number to the thousands, hundreds, tens and units of the multiplicand are thus delivered to the distributer terminals 111, 110, 109, 108 and routed to the millions ... thousands totalizer denominations respectively since stage IV is active because of the application of a priming voltage at the point 2260 from the stage IV control tube 2050. At the end of the operation of the units bank of the gener