Patent GB-641737-A (GB)
Abstract: 641,737. Calculating-apparatus. FELT & TARRANT MANUFACTURING CO. Nov. 5, 1947, No. 29504. Convention date, Sept. 21, 1940. [Class 106 (i)] In a calculating-machine having denominational orders of actuating mechanism for actuating the accumulator, and denominational orders of digit keys for controlling the actuating mechanisms, settable mechanism is provided which is operable in response to the depression of any one of the digit keys for initiating the operation of the actuating mechanisms in all denominational orders higher than that of the depressed key, whereby nines are added to the accumulator in all these higher orders. General description. The key-responsive, power-driven machine shown is generally of known construction. Each column of digit keys 24 controls the rotation of an accumulator actuating pinion 26 meshing with a rack 42 which has a downward idle stroke controlled by each key. Each rack 42 is connected respectively to a hook 58 by a link 59, and to a movement controlling bar 61 by a link 62. Upon depression of a key 24, the stem 47 thereof depresses a bar 48 of a parallel motion device, which includes a link 55, to cause a dog 64 to move the hook 58 into engagement with a toothed wheel 65 driven by a motor 44. The wheel 65 pulls the link 59 to the left to move the rack 42 downwardly through a compensating device 63. This downward movement is stopped when one of the lugs on the control bar 61 engages the stem 47 of the key 24. The link 59 extends a spring 46, which is connected at one end to the frame 22 of the machine and at the other end to a guide member 60 which is pivoted to the link 59. The hook 58 is automatically released from the wheel 65, and the spring 46 acts through the link 59 to move the rack 42 upwardly to cause an adding movement in the accumulator. Subtraction. Subtraction is by complemental addition, but to prevent tens being added to the left of the highest order of the minuend means is provided for automatically adding nines across the machine in all columns to the left in which the first key of the subtrahend occurs, in order to bring all of the higher denominational wheels to zero position. The left or highest order key of the subtrahend must be depressed first, and after this operation, the means for adding nines is automatically thrown out of operation, and the machine is set for ordinary adding operations. On the left of the keyboard is an " add key 71 and a " subtract " key 72, their stems 73 being pivotally connected to the opposite ends of a walking- beam lever 74, Fig. 2, pivoted at 75. Depression of either key rocks a shaft 78 by means of a link 76 and a disc 77, the latter being located in either of two positions by a spring-pressed lever 79. In each order of keys 24 the shaft 78 has lugs 85, 86, Fig. 8, secured thereto, each lug 86 being adapted, when the " add " key is depressed, to engage an arm 87 pivoted on a U-shaped lever 89 journalled on a transverse shaft 91. A spring 92 connects the other end of the arm 87 to the lever 89. When the " subtract key 72 is depressed, the shaft 78 is rocked to allow the arms 87 to rise and dispose shoulders 93 thereon in the path of the lower ends of pivoted levers 95, Fig. 3. Each lever 95 at its upper end embraces a stud 98 on the associated link 55 which, as described above, moves to the right upon depression of a key 24, whereby the lever 89 is rocked counterclockwise. An arm 99 on each lever 89 then moves a latch 102 to allow a hook 113 on a double-hooked lever 105, pivoted on a vertical pivoted lever 107, to engage a pin 114 on the associated guide member 60. Thus when a key 24 is depressed, hook member 58 engages the rotating wheel 65, link 59 and guide-member 60 are moved to the left, and the upper end 118 of the lever 107 engages the stud 98 on the link 55 of the next higher denominational order. This link 55 is thus moved to the right to impart motion to the parallel motion device in that higher order, and since no key 24 has been depressed in such order, nine is added into the accumulator. The second hook 119 of the lever 105 engages the pin 85 to reset the shaft 78 and rock the lever 74, thus pulling down the " add " key 71 and restoring the " subtract " key 72; the machine is thus reset for adding operations. Means to rock the levers 89 in all other higher orders to cause nines to be added therein, comprises a pin 121 on the lever 107 adapted to engage a finger 122 (not shown) on the lever 89 of the next higher order as the lever 107 of the lower order is swung by the hook 113 and pin 114. This action is repeated successively in all higher orders to the left of that in which the first figure of the subtrahend is introduced. Transfer from the highest denominational order to the overflow numeral wheel is prevented in subtractive operations in machines where there is no actuating mechanism in the highest order. A curved pivoted lever 124, Fig. 2, engages under a lateral extension 127 of the carrying pawl 41, and can be actuated by a link 128 to lift the pawl into inoperative position. The link 128 is secured to an arm 129 on the lever 107 in the highest denominational order.