Patent GB-653748-A (GB)
Abstract: 653,748. Calculating-apparatus. REMING- TON RAND, Inc. Feb. 17, 1948, No. 4634. Convention date, Sept. 27, 1946. [Class 106 (i)] A calculating- machine for computing and accumulating products comprises, in each order, a logarithmic spiral pair designed to enter on an accumulator products within the range 1 to 81 when the sum of the logarithms of two digits to be multiplied is applied to it. The machine shown has eight orders and eight spiral pairs, the input elements of which are each fast with a gear 113 meshing with a driving rack 130. A pinion 143 on each rack 130 engages between two further racks, the upper 141 being reciprocated at each cycle over a distance proportional to the logarithm of a digit of the multiplicand, and the lower 142 a distance proportional to the logarithm of a multiplier digit. A reciprocation proportional to the sum of these logarithms is thus applied by the main rack 130 to the input spiral L so that the output spiral moves to and fro through an angle proportional to the product. This movement is transmitted through gears 110, 115 to the corresponding one of a series of product wheels 116 for entry on an accumulator 120, the return or forward drive being taken for positive and negative entries respectively according to the direction of rotation of the hand operating shaft 140. The multiplicand is entered on a keyboard 150 covering four orders and the multiplier digit by digit, upon successive turns of the shaft 140, on a single set of nine keys 151, the keyboard 150 being traversed laterally to co-operate with successively higher orders of the racks and spiral pairs, and to enter partial products in four orders simultaneously at each stage. To allow of this the accumulator is of the " crawl-carry " type and is substantially as described in Specification 272,569, [Class 106 (i)]. Reference is made to U.S.A. Specification 1,503,810 in connection with the spiral pair. Specification 608,033 also is referred to. Key setting - mechanism. The racks are moved forwardly by springs 135 and returned by a common restoring bar 137 reciprocated by a cam 230 on the operating-shaft 140. The keys control stop mechanism to the forward movement, but those not opposite the keyboard 150 are locked by pawls 180 engaging the wheels 110. The stems 160 of the multiplicand keys 150 in each order are spaced logarithmically to serve as the stops for the upper rack 141. A locking slide 163 holds a key down until released by operation of another key in the order, or by pushing-in the end of the slide to enter zero in the order, in which case a camslotted bar 168, actuable by any one of the keys, releases a stop 166 to lock both the racks 130 and 141. The nine multiplier keys 151 are connected to transverse bars 205 extending across all eight orders and provided with clearance slots 212 for the lower racks 142. The bars are spaced logarithmically and that of the key depressed acts as a stop to limit rearward movement of the appropriate lower racks 142. A further bar 215 acts similarly to the stop 166 to prevent movement of the main rack 130 if no multiplier key is depressed for zero entry. Each rack 142 normally stands in its 1 position and, when 1 is entered in both multiplicand and multiplier, 1 is entered on the accumulator by movement of the rack 141 alone up to its 1 position and through short (one tooth) non-logarithmic circular extensions 129 of the spirals. Total-taking mechanism. The accumulator is mounted between depending arms of bellcranks 124 rockable about the shaft 125 of the total indicator under the control of a cam 245 on the operating-shaft 140 so as to engage its pinions 122 alternatively with the product wheels 116 or a set of restoring racks 250. These racks are normally held down and inactive, against the action of springs 255, by respective locking levers 302 (Fig. 19) held in position by a restoring bar 308 releasable by depression of a total-taking key 333. Each locking lever, except that for the units order, is also held down by a blocking member 312 tripped by entry of a finger 316 of the locking lever of the next lower order in a notch 408 of its accumulator wheel. Consequently, when the total key 333 is depressed, the racks 250 rise in succession, commencing with the units, to restore the accumulator sections to zero, and apply the amounts entered to indicator wheels 251 or appropriately set printing types 252. General operation. As the hand shaft 140 is turned one revolution anticlockwise to enter the partial product at each position of the keyboard 150, the cam 230 moves the racks forwardly to the key-set positions and then returns them. The cam 245 engages the accumulator with the product wheels on the return stroke to add the partial product into the accumulator. To subtract the partial product, the shaft 140 is turned clockwise and this causes the accumulator to be engaged with the product wheels on the forward stroke instead. After taking a total, the mechanism is restored by turning the hand shaft 140 with no entry on the keys 150, 151 so that the racks 130, 141 and 142 cannot move. A cam 262 on the shaft 140 first relowers the restoring racks 250, so zeroizing the total indicator 251. A further cam then returns the restoring bar 308 into locking engagement with the total key 333 so that the racks 250 are again held down by their locking levers 302.