Patent GB-800570-A (GB)
Abstract: 800,570. Calculating-apparatus; transfer mechanism; zeroizing-mechanism. BELL PUNCH CO., Ltd. April 19, 1955 [May 3, 1954], No. 12861/54. Class 106 (1). A key-actuated or key-responsive calculating machine with actuating mechanism for each denomination has direct subtraction mechanism. The invention is embodied in the key-responsive machine described in Specification 699,914 having, for each of several banks of keys, a curved actuating rack which is moved into engagement with a driving pinion for the totalizer during its return stroke so as always to rotate the pinion in the same direction. Addition and subtraction. Each driving pinion 4 has secured to it a pinion 90 which is connected to a numeral wheel pinion 91 by a single pinion 95 for addition or by a pair of constantly meshing pinions 96, 100 for subtraction. The pinions 95 and 96, 100 are carried by an arm 93 rockable with a shaft 94 operable by a slide 153 carrying at its lower end a roller 156, Fig. 5. The machine is conditioned for subtraction by moving a lever 141, Fig. 7, from a right-hand limb of a U-shaped slot 174 in the casing to the other limb, the lever 141 terminating in a ball 142 held in a socket. The lever 141 is embraced by a lever 165 so arranged that, when the lever 141 is moved to the subtraction position, it moves beneath the roller 156 and lifts the slide 153 against a spring. The slide 153 rocks the arm 93 so as to disengage the pinion 95 and engage the pinions 96, 100. Transfer mechanism. At transfer during addition, one or the other of two followers 110, 111 drops into the depression of a cam 106 driven with the numeral wheel through gears 101, 102. The followers are respectively integral with pawls 114, 115 co-operating with a cam 116 which is urged to rotate counterclockwise by a drive shaft 125 acting through a friction coupling formed by a spring 130 and gears 132, 117. Thus, at transfer, the cam 116 and the gear 117 rotate through one-half of a revolution until held by the other pawl. The gear 117 carries two studs 133 and during the rotation of the gear, one of these advances by one step a wheel 7 fast with the pinion 4 of the next higher order to enter the transfer digit. During subtraction, the numeral wheel is advanced in a reverse direction and for this reason an additional reversely-shaped cam 105 is provided and the followers 110, 111 are shifted from the cam 106 to engage the cam 105. The cam 116 is sufficiently wide to remain in cooperative relationship with the pawls 114, 115. The transfer unit is entered into the pinion 4 in the same sense as in addition, but the numeral wheel is advanced thereby through the reverse gearing employed for subtraction. For shifting purposes, the followers 110, 111 are engaged by bifurcated ends of arms 124 fast on a spindle 135 which is cross-pinned at 151, Fig. 5, to a block 140 on the control lever 141. Thus, when the lever 141 is moved in its slot 174, Fig. 7, the spindle 135 is first slightly rotated so that the arms 124 disengage the cam followers 110, 111, then it is moved axially to move the followers into alignment with the other cam, and finally it is reversely rotated to allow the followers to engage the other cam under the action of a spring 118. Zeroizing. As each driving pinion 4 is rotated, a spring 176, the inner end of which is connected to the wheel 7 fast with the pinion 4 and the outer end of which bears frictionally on a fixed housing, is loaded so that when a detent 175 is disengaged from the pinion 4, the latter will drive the numeral wheel to its zero position as determined by the abutment of the operative transfer cam 105 or 106 with one of the followers 110, 111. Specifications 516,535 and 522,721 also are referred to.