Patent GB-706445-A (GB)
Abstract: 706,445. Calculating apparatus. NATIONAL CASH REGISTER CO. Nov. 19, 1951, No. 27089/51. Class 106 (1) A calculating or similar accounting machine comprises an add-subtract totalizer, an electromagnetically operated clutch for selectively engaging the totalizer with its actuators, and a plurality of electromagnetic relays adapted for selective operation by the control elements of the machine to effect energization and engagement of the clutch at predetermined instants during the operating cycle of the machine as required to effect the selected function. The invention is applied to an Ellis machine, most of the functional control mechanism being replaced by electrical equipment. Each machine function is represented by a relay, i.e. there are separate relays for addition, subtraction and total-taking as regards each totalizer. A relay is energized to initiate a function, either automatically under control of the paper carriage or manually by key depression, and the operations which then ensue are controlled by timing contacts 125, Fig. 9, selected by the relay and operated at appropriate parts of the cycle by cams 124 on a main motor-driven shaft 122. Multi-contact relays are used extensively for interlocking and other purposes. Provision is made for the conversion of complementary overdrafts for repetition of a preceding function with the add/subtract control reversed in order to cancel the entries, and for clearing of all the totalizers in one continuous series of operations. Machine control by paper carriage.-A field of sensing levers 322, Figs. 25, 28, is provided in a frame 300 behind the paper carriage 6, Fig. 2, with the tips of the levers in two rows for engagement with variously toothed selector bars 388, Figs. 2 and 28, arranged in a selector carriage 350 connected by arms 351 for transverse tabular movement with the paper carriage. The sensing levers engage contact springs arranged in upper and lower sets 307, 315, and a spring-loaded bar 331 normally bears down on the levers to maintain the contacts separated. A magnet 336 is energized at the commencement of a machine cycle and its armature raises the bar 331 by means of plungers 330 so that those contact springs whose levers 322 are not obstructed by teeth of the selector bar 388 are permitted to close to control the machine function. One of the levers 322 is fitted with a roller 392 projecting above the level of the tips of the other levers, so that this lever is rocked immediately a selector bar bearing a tooth in register with it reaches the sensing field and closes its contact springs 398 to energize the magnet 336 and initiate operation. The sensing field frame 300 is removable from the machine for adjustment, the wiring to the contact springs being taken through connector jacks 309, 311. Selector bars 388 may be inserted in any tabular position of the carriage 350 and teeth removed from them according to the functions required in these positions. The bars are secured between the notched side members of a frame 353, which is removable from the selector carriage and, when in position on the carriage, can be adjusted longitudinally thereof into three alternative positions to bring different sets of selector bars into the tabular positions of the paper carriage set by the stops 460, Fig. 2. A notched spring-loaded lever 372 on the frame engages a pin 377 oh the selector carriage to secure the frame in adjusted position. By this means the machine can be pre-adjusted for three alternative programmes. Machine release.-When the carriage reaches a tabular calculating position, an initiation relay is energized over the sensing field contacts 398, the circuit also including contacts operated by a stop 460 on the carriage form bar 148 Fig. 2, so as to ensure synchronism of the selector and paper carriages ; if this is not so a warning lamp 147 is illuminated. The relay thereupon (1) energizes the sensing field magnet 336, (2) breaks the circuit of the lamp 147, (3) applies potential to the sensing field contacts, and (4) prepares the circuit of the drive motor clutch. The machine can then be released by the motor bar 38, if not set to do so automatically by the selector bar or by repeated cycling under control of a "repeat" key 133; in either case a pair of main release relays are energized which, inter alia, energize the motor clutch magnet. Automatic release is, however, prevented following tabulation by the typewriter section 12 or operation of a " non-auto " key 139. Totalizer engagement for addition and subtraction.-There are ten totalizers arranged in pairs above and below rearwardly extending differential racks. Each has an associated add relay and eight also have respective subtract relays. Engagement is effected by a constant excursion rack 244, Figs. 15 and 16, operated by a crank 240 on a main rock shaft 50, the rack engaging wheels 245 on engagement control rock shafts 247 of the totalizers. Each wheel 245 is loose on its shaft 247 and is clutched thereto in add or subtract timing by an electromagnetic clutch 246. In subtract operation, a second clutch 260 is also engaged so that mechanism 269, 270 is operated from the shaft 247 to engage the subtract pawls of the totalizer in place of the add pawls. To condition the machine to select a particular totalizer for add or subtract operation in a columnar position, the corresponding tooth is removed from the appropriate selector bar 388. This results in closure of the corresponding sensing field contacts when the columnar position is reached and energization of the add or subtract relay of the selected totalizer. The relay prepares the circuit of the clutch 246 through add or subtract timing contacts 125, Fig. 9, so that, when these latter operate during the ensuing cycle, the clutch is energized and the totalizer engaged in add or subtract timing as selected. There is a delay in engagement of the clutch to allow the flux to build up ; actual engagement occurs when driving dogs on the wheel 245 register with notches in the rim of the clutch casing. The sensing field may be preset for manual selection of addition or subtraction. A relay is energized by the sensing field contacts upon reaching the columnar position where this form of operation has been preset and prepares a circuit which is completed to the add or subtract relay of the No. 1, 3 or 4 totalizer as selected by two-way add/subtract switches 144- 146 for these three totalizers. A "nullify" key 138 is provided to break the holding circuits of set add or subtract relays in order to cancel their settings. Total and subtotal operations.-In columnar positions preset for total taking, a total relay for the selected totalizer is energized, whereupon the clutch 246 is energized over timing contacts 125 to engage the totalizer at the appropriate part of the machine cycle. The zero stops are released by energization of a magnet 411, Fig. 15. A hook 412 is rocked by the magnet into engagement with a crank pin on the main shaft 50, so that a bar 400 carrying the hook is slid rearwardly and operates the amount key detent bars to release the zero stops. The magnet 411, as well as one for controlling symbol printing, is energized over separate sensing field contacts 315. In subtotal operations, a subtotal relay is energized in addition to the total relay, and this changes the timing contacts 125 to modify the timing of engagement accordingly. The sensing field can be preset for manual total-taking of three of the totalizers. A relay for this function is energized and appropriately modifies the connections. Overdraft arrangements.-Mechanism is provided for converting complementary overdrafts on totalizers 1, 3 and 4 into true negative amounts, this involving use of the No. 2 totalizer. When either totalizer 1, 3 or 4 is overdrawn, its overdraft shaft 520, Fig. 16, rocks and closes contacts 526 to energize a corresponding overdraft relay. The relay locks over timing contacts 125, Fig. 9, which conditions the overdrawn totalizer for total-taking and the No. 2 totalizer for subtraction. In two successive cycles which then ensue the complementary amount is first cleared from the overdrawn totalizer and subtracted from the No. 2 totalizer to give a true negative amount which is then cleared from the No. 2 totalizer and printed. The overdrawn totalizer may, alternatively, be subtotalled during the first cycle so leaving the complementary amount standing. Release for the two-cycle operation is effected automatically or manually according to the setting of a two-way switch 512. In one position, operation occurs automatically in a columnar position preset for total-taking if the totalizer selected is overdrawn. In the other position, the machine stops, a lamp 511 marking the overdrawn totalizer is lit and the machine is then released manually. Repeat operation.-Depression of a " repeat " key 140 closes contacts to energize a magnet 430, Fig. 15, whose armature thereupon obstructs a link 433 connected to a pawl 416 by which a crank pin 419 on the main shaft 50 normally displaces the bar 400 rearwardly to release operated amount keys at the conclusion of a cycle. Obstruction of the link 433 results in disengagement of the pawl 416 from the pin 419 so that the amount keys remain set for a further cycle initiated by the " repeat " key depression. The amount keys remain depressed at the end of the repeat operation so that further entries can be made by repeated actuation of the "repeat" key. Reverse operation.-Entries made into one or more totalizers under control of a selector bar may be cancelled by tabulating the carriage back to the position and operating with a " reverse " key 143. This energizes relays which reverse the control, as between the add and subtract relays, exercised by the selector bar so that, upon operation with the same amount entered on the keyboard, the previous entries into the totalizers are canc