Patent GB-672210-A (GB)
Abstract: 672,210. Calculating-apparatus. FELT & TARRANT MANUFACTURING CO. Aug. 7, 1947 [July 16, 1943], No. 21600/47. Class 106 (i). In a power-operated, normally keyresponsive calculating-machine having a register comprising denominational orders of accumulating mechanism, keys controlling the mechanism for both positive and negative forms of calculation, selectively-settable means for converting all the orders except the units order of the accumulator mechanism into key-set mechanism leaving only the units order open to key-responsive operation, there is provided means rendered operative by the last means whereby, when a key of the units order mechanism is depressed, the orders to the left in which keys may have been previously depressed will be power-operated and controlled digitally by such key setting. The machine shown is basically of known type, and enables calculations according to the four rules of arithmetic to be made. The machine can be manually pre-set for key-set operation during negative calculation, and manually pre-set for key-responsive operation during positive calculation, but is automatically reconditioned for positive calculation upon completion of each subtractive calculation. Upon depression of a digital key 36 in any column, its stem engages and depresses a parallel motion bar to operate a power trip mechanism to cause a clutch hook to engage a rotating toothed wheel ; a tension spring is stretched which, when released, acts through a yielding clutch to rotate a gear sector 61 (not shown), engaging a pinion 63 (not shown) in a primary totalizer. Primary and secondary totalizers. The pinion 63 rotates a co-axial lantern wheel 65, Fig. 5, which drives a numeral wheel 73 through gears 66, 68 and 71. The gears 66, 68, 71, the numeral wheels, and a known tens transfer means form the primary totalizer and are in a rock frame comprising spaced plates 78 adapted to rock about a shaft 69 in a clearing or zeroizing action. Similarly, the secondary totalizer includes, in each order, a combined wheel and gear 65<SP>1</SP> which can drive a numeral wheel 73<SP>1</SP> through gears 66<SP>1</SP>, 68<SP>1</SP> and 71<SP>1</SP>, and includes a frame comprising spaced plates 781 adapted to rock about a shaft 69<SP>1</SP> during a zeroizing action. Mounted in each frame section of the primary totalizer, is a transfer gear 79, Figs. 5 and 6, engaging at all times the gear 66 but slidable axially of a shaft 81 to engage also the gear 651 of the secondary totalizer when the frame 78 is rocked. Depression of a transmission or transfer key 92 operates levers 89, 91, 88 to slide a cross bar 86 which moves forks 83 engaging the hubs of the gears 79, and the gears 79 thus also engage the gears 65<SP>1</SP>. The secondary totalizer includes gear sectors, adapted to be driven by the stored energy of coil springs 95 (not shown), engaging the gears 65<SP>1</SP>, but normally prevented from driving these gears by means comprising toothed detent wheels controlled by detents which are unlocked by curved arms 84 on the frame 78 on the rocking of the primary totalizer in a zeroizing action. When this occurs, the gear sectors operate the secondary totalizer to an extent controlled by the distances rotated by the return of the primary numeral wheels to zero. Thus the total transfer key must be depressed at the same time as a zeroizing lever 104, Fig. 10, for the primary totalizer, is depressed. Means to co-ordinate these movements comprises a lever 105, Fig. 10, adapted to move into a notch in the stem of the transfer key if the lever 104 is actuated without depressing the transfer key, so that the latter cannot then be depressed. If the transfer key is depressed first, it is held depressed until zeroizing action is complete. Energy again is stored in coil springs in the secondary totalizer after a transfer operation by a gear 109, Fig. 10, secured on the power drive shaft 55, adapted to be engaged by a gear 111 carried by a pivoted arm connected by toggles 114, 115 which, under the action of a spring swing the arm to mesh the gears. Through a system of linkages 120, 121, Figs. 6 and 10, controlled by depression of the transfer key 92, a pin 123 on a lever 124 of the zeroizing mechanism engages a hook 122 on the link 121 to move it forward to allow the toggles 114, 115, to mesh the gears 109, 111. Rotation of the gear 111 operates a lever 128 through a pitman mechanism to energize the coil springs of the secondary totalizer. The gear 111 has two extra long teeth which assist in breaking the toggle 114, 115. The rock frame 78 of the primary totalizer is returned to active position as soon as a transfer is made, to leave the secondary totalizer wheels free to receive their carrying action. To permit this return there is a jointed linkage 145, 146, Fig. 10, between a clearing lever segment 144 and the lever 124, which linkage is adapted to be broken by the upper arm 149 of a lever 147 which is rocked by a power-operated lever 131. A detaining toggle 154, 155, Fig. 30, for the rock frame is broken before the jointed linkage 145, 146. The arm 149 also engages a transfer lock release lever 168 which moves the lever 105 out of engagement with the stem of the transfer key 92. In extension work dealing with fractions of part of a cent, the lower three orders of the primary totalizer are prevented from making a transfer to the secondary totalizer by depressing a key 174, Fig. 10, which moves a two-armed blocking lever 179 to engage the lug 84, Figs. 5 and 6, of the lowest order, which lug retains a separate slide 183 for the forks of the transfer gears 79 of the three lower orders. The secondary totalizer is zeroized in a manner similar to the primary totalizer. Its rock frame is moved by a zeroizing lever 189, Fig. 1, mounted on a shaft 191, a lever 192, link 196, levers 197, 199 and 201, a rock-shaft 202, and toggle levers. This rock frame has a detaining toggle 212, 214, Fig. 6, controlled by the transfer key 92 through the lever 89. The secondary totalizer frame swings in before the primary totalizer is engaged with the pinions 65<SP>1</SP>. Addition. Positive and negative complemental stop bars 222, 223, respectively, Fig. 3 (not shown), are provided in each order, either of which can be engaged by a link connected to the gear sector 61, Fig. 3 (not shown), this link being controlled from a rock-shaft 243, Fig. 30 ; lock levers ensure that the appropriate bar is selected and actuated. To set the machine for addition, a key 265 is depressed to swing a beam lever 267 which, through a link 269 and lever 258, rocks the shaft 243. Multiplication. This is by repeated entry of the multiplicand as in addition, the keys 36 being struck simultaneously. Division. Depression of a key 275, Fig. 30, rocks the shaft 243 through the link 269 and lever 258 ; toggle links 261, 263 and a spring 274 prevent return of the shaft. The shaft, as described above, operates mechanism to connect the negative stop bars 223 with the gear sectors 61. Nine is added in every order, except the units order, where a cipher appears in the divisor. For subsequent positive calculations, the addition key 265 must be manually depressed, and the division key is then released. Subtraction. The machine becomes key-set operated in all orders except the units order, which will be key-responsive, when a key 285 is depressed. On depressing the key 285, a pivoted three-armed lever 289, Fig. 10, rocks the shaft 243, Fig. 30, to connect the complemental negative stop bars 223 with the gear sectors 61, and also rocks a shaft 302 having a series of lugs thereon, one for each denominational order of the machine. These lugs actuate latch levers co-operating with spring- pressed dogs 313 (not shown), which can prevent the power clutch hooks from engaging the power drive. By this arrangement, all the digital keys 36, except those in the units order, can be depressed without a power action of the machine. Depression of a key in the units order initiates a power drive in that order and progressively throughout the machine. Safety means ensure that units order keys cannot cause a power action unless the key 285 is fully depressed. In the present machine the nines in the subtrahend cannot be ignored, as is usual, on account of the consecutive action across the machine when the units key is depressed- Therefore, to produce continuity of action in all orders the nines keys are depressed, but any action resulting from the depression thereof is blocked, since the corresponding negative stop bars 223 are prevented from movement by levers 359, Fig. 24 (not shown), arranged in the keyboard, which can be engaged by notches in the nines keys when the latter are depressed. These levers are adapted to be moved for key engagement by lugs on a transverse shaft which is actuated through a link 381, Fig. 10, by the three-armed lever 289 controlled by the subtraction key 285. When a cipher occurs in the units order, the equivalent of ten is added by depressing a cipher key 382, which initiates a power action in the units order, and consecutive power actions in all the other orders. Ciphers appearing in the other orders are ignored. The mechanism set by the subtraction key 285 is automatically cleared during the power action, and the positive complemental stop bars 222 are set for addition or multiplication. To subtract a number from a number registered in the secondary totalizer, a key 421, Fig. 30, is depressed, the complement of the subtrahend set up on the keyboard, and a transfer effected by depressing the key 92 and operating the lever 104. The key 421 also prevents carries from taking place to the overflow wheel of either the primary or secondary totalizer. It is adapted to rock the shaft 302 through levers 425, 428, 431, and a disc arrangement on the shaft 302, so that the latter operates as it does when the key 285 has been depressed. The lever 431 rocks the d