Patent GB-601375-A (GB)
Abstract: 601,375. Calculating-apparatus. FELT & TARRANT MANUFACTURING CO. July 23, 1943, No. 12027. Convention date, Aug. 8, 1942. [Class 106 (i)] In a dividing machine having an actuator for each order of the totalizer, each actuator being controlled by a respective column of keys, means are provided for causing the automatic operation of any actuators below that of the highest order in which a digit key has been depressed. To perform division, the dividend is entered, a division key is depressed followed by the depression of digit keys representing the divisor multiplied by a power of ten to bring its highest figure adjacent the highest or next highest figure of the dividend. The machine then functions in a key-responsive manner to subtract the dividend (by adding its complement, modified as stated below) from the divisor. The complement differs from that added in normal substraction in that nines are not entered in denominations higher than that of the highest significant figure of the divisor (multiplied by a power of ten if necessary). Nines are added in denominations below that of the lowest significant divisor figure, excepting that ten is added in the units denomination. The depression of the divisor digit keys is repeated until the figure in the highest changing denomination in the totalizer is equal to the number of depressions and is continued (if necessary) until the amount represented by the totalizer figures adjacent 'the divisor denominations being depressed are less than the divisor. The operations are then repeated with the divisor multiplied by one less power of ten, and so on. Ultimately, the quotient and remainder will be registered on the totalizer. The invention is shown embodied in a machine of the kind described in Specifications 344,868 and 566,376 in which in adding operations depression of a digit key 24, Fig. 2, depresses a bar 48 connected to an actuation control bar 55 whereby the latter is moved downward and to the right. A dog 67 in the bar 48 depresses a lever 72 to lower a hook 58 into engagement with a continuously-rotating driving wheel 73. The hook 58 is pivoted to a link 59 so that when the driving wheel engages the hook the link is pulled to the left to drive a sector 42 through a yieldable clutch 63. The extent of movement of the sector 42 is controlled by a differential bar 112, Fig. 3, which contacts the stem of the depressed digit key, the totalizer driving pinions 26 being engaged with the sectors 42 during the return stroke of the latter. Subtraction. This mechanism is similar to that described in Specification 566,376. Depression of the " minus '' key 86, Figs. 3 and 4, changes the method of operating of the machine from key-responsive to key-set and subsequently operated, the key 86 depressing a lever 96, Fig. 4, carrying a pawl 99 to rock anticlockwise a shaft 107 to lower lock arms 108, Fig. 3, into the path of lugs 111 on the hooks 58 to prevent engagement of the latter with the driving wheels 73. The minus key 86 also rocks an arm 119 on a shaft 121 carrying arms 123, 124 which move the normal differential bars 112 laterally across the machine away from the digit key stems and bring ninescomplemental bars into operative positions in all denominations excepting the lowest where a tens-complemental bar is provided. The subtrahend is now set and an " equals " key 87 depressed. This operates a lever 128 to rock the pawl 99 to release the lock arms 108 and allow the hooks 58 to engage the driving wheels 73 to add the complement of the subtrahend into the totaliser pinions 26. The lever 128 also operates mechanism which effects the addition of nine (ten in the units order) in those orders in which no digit keys have been depressed. An overflow wheel is provided above the normal highest order totaliser wheel. Depression of the minus key operates mechanism whereby nine is added into the overflow wheel during the subsequent operation of the machine. Division. The division key 301, Fig. 3, rocks the shaft 121 to bring into operation the nines-complemental differential bars (tenscomplemental. in the units denomination) as described under " subtraction above. The division key also shifts a rod 311, Fig. 12, to the left to slide levers 315 into the paths of pins 141 on the actuation control bars 55. The levers overlap in such a way that all control bars 55 to the right of that of the highest significant divisor figure are moved to cause the addition of nine (ten in the units denomination) in any such denomination in which a digit key has not been depressed. To relieve the stress on these connections the movement of the bars 55 is assisted by cams 325 on the clutches 63 driven by the driving wheels 73 engaging rollers 326 on the bars 55. Key latching and releasing mechanism. Error correcting. The dog 67 and hence the bars 48, 55 are held depressed by a latch 66 pivoted on the bar 55. The hooks 58 and links 59 are supported on arms 60 pivoted at 50. A pin 77 on each arm 60 releases the corresponding latch 66 at the end of the outward stroke of the link 59. The digit keys are latched by bars 81 having lugs 82. When the bars 48 are depressed the bars 81 move to the left and the lugs 82 engage slots in the keystems. If a key is held depressed, relatching of the dog 67 and continued operation of the machine are prevented by the engagement as the link 59 completes its return movement to the right of a shelf 71 on the lever 72 with the tail 69 of the still-depressed dog 67. Relatching is also prevented (and the keys allowed to rise) while operation is still in progress by a lever 327 pivoted at 328 and urged clockwise by a spring 333 into contact with the pin 77 on the arm 60, the lever 327 engaging the tail 79 of the latch 66 to hold this inoperative until the pin 77 depresses the lever 327 at the end of the return stroke of the arm 60. The dogs 67 are also unlatched and depressed digit keys released when the zeroizing lever is operated, this lever rocking a shaft 343, Fig. 19, to pull to the right a link 339 engaging a pin 352 on the dog 67 to rock the latter free of its latch 66. In the highest denomination, the dog 67 is freed by a link 361, Fig. 4, pulled to the right when a lock arm 365 is turned clockwise about its pivot 366 by the rocking of the shaft 343 operated by the zeroizing lever. The rocking of the shaft 343 to release depressed digit keys is also effected by depressing a release key 371, Fig. 15, which rocks a lever 374 about it pivot 375 to move to the right a link 379 pivoted to an arm 344 on the shaft 343. Operation of the release key or of the zeroizing lever moves a link 345 to the right, Fig. 18, and this by a cam surface 413 and roller 420, rocks a crank 419 normally connected by a latch 416 and pin 414 to a lever 412 operating a bar 391 having an arm 392, Fig. 2, which rocks the crowding latches 390 to prevent depression of numeral keys and to unlatch the division key as described below. When the minus key is depressed, the connection between the crank 419 and lever 412 is broken by the action of a crank 424 which is rocked clockwise to disengage the latch 416 from the pin 414, the crank being operated by a link 429 controlled from the minus key. When the equals key is depressed, the shaft 138 is rocked clockwise whereby a bellcrank 436 positions a pawl 443 behind a pin 451 on the lever 412. Release of the equals key thus causes the pawl 443 to engage the pin 451 to rock the lever 412 and bar 391 to move to the left, Fig. 21, a bar 394 which removes a latch 406 from a slot in the stem of the depressed minus key 86. The division key 301, Fig. 4, is locked down by a projection 382 on the lock arm 365, this locking being released when that arm is rocked by the shaft 343 operated by the zeroizing lever or by the release key. Upward movement of the division key is effected by a cam surface 385 on the arm 365. Key interlocks. (1) Depression of the minus key 86, Fig. 4, interposes a lug 386 beneath the stem of the division key 301. (2) Depression of the division key blocks the lug 386 to prevent depression of the minus key. (3) Preventing depressions of minus or division keys 86, 301 when digit keys are depressed. The depression of any digit key causes latches 390, Fig. 21, to rock to engage and lock up the remaining keys in the denomination concerned. The end latch 390 of each denomination rocks a bar 391 to move to the right a link 394 to place latches 406 into locking engagement with the stems of the minus key 86 and division key 301. (4) Preventing rocking of zeroizing lever or depression of a release key when the " equals " key is depressed, and vice versa. Depression of the " equals " key 87, Fig. 4, rocks clockwise a shaft 138, Fig. 18, carrying an arm 439 the end 440 of which is thus interposed beneath a roller 420 on a crank 419. A link 345 connected to the zeroizing lever and to the release key is thus prevented from movement to the right and operation of the lever or key is inhibited. Operation of the zeroizing lever or release key moves the link 345 to depress the roller 420 into the path of the arm 439 and thus prevent depression of the " equals " key or operation of the zeroizing lever. (5) The release key 371 and the zeroizing lever cannot be operated simultaneously with digit keys, since operation of the former moves to the left the link 345, Fig. 18, to rock clockwise the bar 391. This rocking is, however, inhibited by the crowding latches 390 if any digit key is depressed.