Patent GB-288672-A (GB)
Title: Improvements in calculating machines
IPC: G06C7/06
Filed: 1926-12-31
Abstract: 288,672. Ball, W. Dec. 31, 1926. Adding and subtracting apparatus.-In a machine, such as that described in Specification 263,505, wherein a pinion engaging with a normally stationary rack and with a key-controlled rack is connected with an actuating racli, the first-mentioned rack is capable of release for movement at transfer. Provision is also made for subtraction as well as addition. The pinion e<11> connected to the actuating-rack e<13> is moved along the lower stationary rack e<4> and the upper rack e<2> controlled by the keys, by means of a link g<1> slotted at g<3> to engage the pinion spindle frictionally. The link is pin-and-slot connected to a crank arm g oscillated from the operating handle f<1> through the gearing shown. When a key has been depressed and the handle is operated the link draws the pinion along and with it the actuating rack until the end e<16> of rack e<2> meets the depressed liey. Meanwhile the totalizing-counter d is disengaged owing to the frictional action of a slotted link d<5> on the counter-supporting bellcrank d<2>. On the return stroke of the handle the counter is re-engaged to receive the item set up as the rack returns to normal position. When it is desired to subtract instead of add, the timing of engagement of the counter is reversed by the use of a finger-lever t. Fig. 9, connected by a slotted link u with the counter-supporting lever d<2>. By suitably manipulating the finger-lever the control of the counter engagement by the machine is over-ridden and the counter caused to engage only on the forward stroke of the machine. Transfer-mechanism.-With the machine conditioned for addition, the passage of a numeral wheel from 9 to 0 effects through a. lug thereon the counterclockwise displacement of a lever e<6>, Fig. 6. This lever has a notch e<23> normally engaged by a detent pawl h<1>, and its lower turned end e<5> serves to lock the stationary rack e<4> to the frame e by occupying notches e<7>, e<8> in each. When the lever is displaced at transfer to free the rack it is held by engagement of the detent pawl with another notch e<24>. During the return stroke of the machine therefore the stationary rack may move to an extent equivalent to the addition of unity. The parts are restored in the forward stroke of the next operation, a pin d<19> on the supporting bell-crank d<2> rocking the detent pawl to allow the lever e<6> to return to effective position under the pull of a spring e<6*>. When the machine is put in condition for subtracting, the lever e<6> is displaced counterclockwise to a still greater extent by a key and link v<2> and is then held by engagement of the pawl h<1> with a third notch e<25>. (See Fig. 7.). The lever e<6> is connected by a spring x<3> with a coaxial lever w the lower end of which is now drawn into the path of the rack c<4> to limit its movement to the right. At transfer, however, a pin on the lower numeral wheel rocks the lever w clockwise to remove its end from obstructing position so that the rack may move to the necessary extent for transfer. The lever w is held, when tripped, by a pawl x pivoted on the lever wand co-operating with notches on the lever e<6>. Zeroizing-mechanism.-The engagement of the counter with the actuators is controlled for zeroizing by means of a finger-lever r, Fig. 11, pivoted at r<1> and connected by the slotted links r<8>, r<12> with a link r' pivoted to the counter-supporting lever d<2>. By suitably shifting the lever r prior to each of the forward and return strokes the automatic control of the engagement by the machine can be over-ridden and the action of the racks upon the counter reversed.