Patent GB-621755-A (GB)
Abstract: 621,755. Calculating-apparatus. AKTIEBOLAGET FACIT. Aug. 8, 1946, No. 23569. Convention date, July 17, 1945. [Class 106 (i)] A calculating machine has settable calculating members comprising, for each order, two rigidly connected parallel discs which on their external peripheries have abutments or steps, the angular distances of said steps from a common origin representing logarithmically all the numbers obtained by multiplying two digits together, while the heights of the steps represent directly the digits 0-9, the steps on one disc representing the units of the product and the steps on the other disc representing the tens. Thus, on turning a pair of discs through two angular distances, a step corresponding to the product of the two individual numbers is reached and this result is fed into a totalizer by means of a feeler mechanism. Steps representing 1x0, 2 x 0, &c. are also provided on the discs. In operation, a number is fed into settable members and successively operated on by an operations mechanism to give partial products which are added and fed to the totalizer. A common keyboard may be used for the settable members and operations mechanism, but the invention is described with reference to two keyboards, nine keys 151 for the operations mechanism being shown in Fig. 6. Setting-mechanism.-This includes the pairs of discs 101, 102 (Fig. 2) which are rigidly united with a curved numeral plate 103, each of them being rockably journalled on a ring 104. Cups 105 between the rings each have an inwardly extending pin 106 (Fig. 1) entering an axial slot in a tube 107 journalled on a main shaft 108 which is pivoted in the frame of the machine. A disc 110, having a tab 111 which engages in an axial slot in a rail 112, is fixed on one end of the tube 107, and the rail is fixed to a disc 141 rigidly fastened on the main shaft (Fig. 2). Thus, the whole unit is axially displaceable with respect to the main shaft. On the internal periphery of each disc 102 are ten steps 102a-k, the distances of the steps 102b-k from the step 102a representing the logarithms of the numbers 1-9, and a spring 119 engages a projection 120 on the disc 101 and presses the step 102a into engagement with a projection 114b on a slide 114. When a number is set up, the slide 114 is moved inwards against the action of a spring 116 to an amount corresponding with the numeral key pressed and a pawl 118, operated by the other end of the spring 119, engages one of a series of teeth 114a. The discs are thus rotated by the spring 119 until an abutment (102a-k) strikes the projection 114b. The unit is also shifted one step axially. Operations mechanism.-The disc 141 has nine recesses 141a-i and is secured to the main shaft, while a disc 143 having nine steps 143a-i is loosely mounted thereon, the recesses and steps being spaced logarithmically (Fig. 6). When a numeral key is depressed, a slidable stop rail 144 is moved and the disc 143 is turned until the step corresponding to the number engages an abutment 144a which is positioned by the slidable rail. A peg 142 on the disc 143 turns the disc 141, and thus the main shaft, against the action of a spring 163. The turning of the disc 143 is effected as follows. The driving shaft 152 (Fig. 7) rotates through one revolution and a cam slot 155a in a cam 154 lifts a roller 156 on a pivoted arm 157. The arm is swung clockwise and, via a spring 159, moves a lever 160 which has a curved rack 161 (Fig. 6) at one end in mesh with a gear-wheel 162 connected with the disc 143. Feeler mechanism.-A carriage 121 (Fig. 2) movable towards the main shaft has numeral wheels rotatable on a shaft 122, each numeral wheel comprising a gear-wheel 123, a toothed disc 124 and a numeral cup 125 united together. The shaft 122 is displaceable in slots in the carriage walls and in its upper position every gear-wheel 123 engages teeth on a feeler rack 126 which is opposite the corresponding disc 101, while in the lower position every gearwheel engages teeth on a feeler rack 127 opposite the corresponding disc 102. Tension springs 128 press each rack 126, 127 against pins 130 (Fig. 3) which are each secured to a hook 131 pivoted on a shaft 132, there being one hook for each order of the totalizer. Torsion springs 133 around the shaft 132 rock the hooks 131 clockwise (Fig. 1) so that projections 131c each strike one of three abutments 134a or 124b or 134c on hooks 135 pivoted on a displaceable shaft 136 and urged by a torsion spring 137 to engage the projection 131c. When the gear-wheels 123 are being moved from one feeler rack to another, a rail 138 secured to a movable shaft 138a engages the toothed discs 124 and locks them in position, while when the carriage 121 moves forward (to position A) comb-shaped locking rails 146, 147 are moved laterally, by the co-operation of cam slots 202 with a stationary pin 203, to lock the racks 126, 127 and prevent a tens transfer which would otherwise occur. A crossrail 139 and a shaft 140 are arranged so as not to move with the carriage 121 and a pusher 149 on the shaft has two cams 149a, 149b, one (149a) co-operating with abutments 131a and 131b of the hook 131 (Fig. 1) and the other with abutments 126a, 127a of the racks 126, 127. After the partial rotation of the disc 141 has been completed, as previously described, a cam slot 168 in the cam 154 (Fig. 7) operates, via a roller 1450, a pivoted arm 1451 and arms 1453, 1454 pivoted at 1455, to cause a locking pin 145 to enter a recess 141a-i and lock the disc 141. Another cam slot 155b of the cam 154 moves a roller 169 which is secured to one of two arms 170 pivoted on a stationary shaft 171. Pins 172 on the carriage 121 are held in slots in the arms 170 and thus as the arms are rotated by the roller the carriage is moved to position A. Multiplication.-To calculate, say, the product 109 x 92, 109 is first set up in the discs 101, 102, and the numeral key 2 on the keyboard 151 is pressed, displacing the slidable rail 144 correspondingly and, as explained, rotating the main shaft 108 via the disc 141 which is then locked by the pin 145. The following steps are then in alignment with the feeler racks 126, 127 of the corresponding orders: in the lowest order, the step for 18; in the next order, the step for 2 Î 0; in the highest order, the step for 2. The shafts 122, 136 enter cam slots in discs 174a, 174b which are pivoted at 175 and the discs may be coupled with either of two cams on the tube 153, one being for addition and multiplication and the other (not shown) for subtraction and division, the change-over being effected by a link (Fig. 8, not shown). For addition, when the cam 154 has rotated almost a half revolution, the shafts 122, 136 are moved downwards to a position in which the numeral wheels 123-125 are disconnected from the feeler racks 126, 127, while the racks are moved backwards. Then the discs 174a, 174b move the numeral wheels upwards and caues the gear-wheels 123 to mesh with the racks 126, while the feeler racks 126, 127 are moved forward, as explained above, to strike the discs 101, 102. In the highest order, the rack 126, in the example given, is pushed inwards by its disc 10<SP>1</SP> and rotates its numeral wheel two steps, while the rack 127 moves fully forward. In the next order, neither of the racks are pushed inwards. In the lowest order the rack 126 strikes the step for 18 and its numeral wheel is rotated eight steps; the rack 127 moves inwards one step, but is not in mesh with a numeral wheel. Further rotation of the cam 154 moves the numeral wheels into mesh with the racks 127, and the carriage 121 returns to its back position, while the spring 128 draws the rack 127, which has previously been moved one step, to engage the pin 130, thus rotating the corresponding numeral wheel one step. After the pin 145 has locked the disc 141 in position 2 in the above example, the disc 143 returns to its initial position and the 9 key may then be depressed. When the carriage 121 returns to its rear position, the pin 145 unlocks the disc 141 which then rotates towards its initial position while the disc 143 is moving counterclockwise towards the stop rail 144. Simultaneously, the unit carrying the discs is shifted one step axially, so that three operations occur together, viz. tens transfer, moving the unit to a position corresponding to the next numeral of the multiplier and shifting it axially. A cam disc (not shown) moves a clearing rail 187 to clear the discs 101, 102 which rotate counter-clockwise (Fig. 1) until a projection 188 strikes the rail. Pins 189 release the hooks 118 and allow the slides 114 to return. Transfer mechanism.-One of two diametrically opposed transfer teeth 148 on the disc 124 rocks the hook 135 outwards, thus causing the spring 133 to rock the hook 131, in the next higher order, clockwise. When, therefore, the racks are pulled back by the springs 128, as just described, the numeral wheel in the order which is receiving a tens transfer will be rotated an additional step. A pushing member 149 operates at each such transfer to assist the springs 128. Two tens transfers may be effected during one rotation of the machine, in case a numeral higher than two remains accumulated from a prior operation, as the tens transfer the numeral wheels are moved upwards to mesh with the racks 126. A restoring bail 150 is movable to restore the hooks 131 and thus the racks 126, 127. Addition, subtraction and division.-For addition, each item is set up in the discs 101, 102 and entered into the totalizer by multiplying by 1. For subtraction, the link previously mentioned (Fig. 8, not shown) is operated, while for division the dividend is set in the discs, which is shifted to its extreme left (Fig. 2), 'then multiplied by 1 to transfer it to the numeral cups 125. The divisor is then set in the discs and subtracted a sufficient number of times.