Patent GB-217910-A (GB)
Abstract: 217,910. Burroughs Adding Muchine Co., (Assignees of Mueller, F. O.). June 18, 1923, [Convention date]. Adding and subtracting apparatus.-In an adding machine, for example, of the Hopkins type, wherein subtraction by the complementary method is performed, an attempt to subtract a larger from a smaller number results in the display of a warning signal and the locking of the motor release means. A specific manipulation by the operator must then be performed in order to free the release-means preparatory to the performance of the requisite succeeding operation. The invention is set forth as applied to the Hopkins machine described in the U.S.A. Specification 1,206,113 wherein during an operation effecting an overdraft, parts are positioned so that in the succeeding operation to print the result the printing mechanism is disabled and a bell sounded. The means whereby the parts were positioned are employed in slightly modified form in the present case but the signalling and locking effects occur during the operation producing the overdraft. As shown in Fig. 9, the transfer-effecting toothed sector 129 belonging to the highest denomination wheel 268 of the rear or minuend totalizer has, associated with it, two similar but toothless sectors 129<a>, 129<b> and all three sectors are under the control of springs 132. Secured to the wheel 268 is a cam disc 420 having a nose 421 circumferentially displaced with reference to the transfer tooth 120 of the wheel 268. A pawl 121<a> similar to the trip pawl 121 is bevelled (at one corner only) and the arrangement is such that when the wheel 268 stands at 0 the pawl 121<a> is displaced by the nose 421 as shown in Fig. 9 but when the wheel is at 9 the pawl occupies the position shown in Fig. 12. When an ordinary, subtraction takes place, the addition to the minuend on the rear totalizer of the complement (plus one) of the subtrahend. results in the highest wheel 268 passing to 0 and consequently the lever 124 associated with the trip pawl 121 is thrust forward and its bevelled end 127<c> raises a pin 554 on a latch lever 127<a> so that a shoulder 127<d> is freed from the comb plate 128 and the lever advances to the position shown in Fig. 9. The immediately following engagement of the nose 421 with the pawl 121<a> shifts the lever 124<a> having a pin 126a underlying the latch lever 127<a> but this is an idle movement inasmuch as the latch lever has already been raised and tripped by the passage of wheel 268 to 0. When subtraction resulting in an overdraft takes place, the wheel 268 will stand at 9 and therefore the latch levers 127, 127<a> will remain latched. The depression of the subtraction key positions a cam 455, Fig. 1, on the main shaft 81, and also slides a shaft 220 axially so that the cam may act upon the lever 425 connected by a link 424 with a lever 422 connected by a slot and pin 129<c> with the sector 129b. In a normal subtracting operation the lever 425 is rocked by the cam 455, and the link 424 through lever 422 moves the latch lever 127<a> rearwardly until it again latches, thus holding the lever 425 depressed until when the wheel 268 passes to 0 the action of latch lever 127 again trips lever 127<a>. If, however, the subtraction is abnormal, the wheel 268 stands at 9 and so lever 127 is not moved to displace lever 127<a> and therefore the lever 425 remains depressed throughout the operation of the machine. As described below, the machine is locked as the. result of this, and a particular manipulation is necessary to enable it again to operate. If this manipulation is performed with the " P " key depressed, the incorrect result on the minuend totalizer is transmitted to the pendants and the totalizer zeroized, and the printing mechanism is disabled by a connection through a link 423 with the lever 422. The zeroizing of the totalizer results in displacement of the trip pawl 121<a>, Fig. 9, and, through its lever 124<a> and pin 126<a>, the unlatching of lever 127<a> so that levers 422, 425 may return to normal position. If the subtraction key is then depressed and the machine operated, the complement of the amount on the pendants, that is the correct negative difference is transmitted to the rear totalizer and, by depression of the " overdraft " key and operation of the machine, may be printed in red. Locking the machine when abnormal subtraction occurs. The machine is normally released for operation by depression of a motor bar 79 carried by a pair of connected pivoted arms 529, the left one of which has a lug 532 projecting over a neighbouring bell-crank lever 522 connected to a link 523 adapted to release the motor. A spring-controlled sliding bar 520 has a lug 520<a> normally standing at the left of the bell-crank 522. In an abnormal subtraction, as stated above, the lever 425 remains depressed throughout the operation, and this, through a bell-crank lever 505, link 508 and lever 509 causes a bar 513 to advance and, by means of a wedge 517 thereon and a pin 519 on the bar 520, shift the. latter to the right to position the lug 520<a> below the bellcrank 522 and so lock it against depression for effecting the next operation of the machine. Releasing the machine after locking. The bar 513 is connected with the lever 509 by a pin 511 on the latter engaging the vertical portion of an L-shaped slot 512 in the bar. To release the machine after the locking due to abnormal subtraction has occurred, an error key 544 is pushed in. This causes a bent bar 546 to slide to the right against spring action and by means of a wedge-shaped lug 553 raise the rear end of bar 513 until the horizontal arm of its slot is on a level with the pin 511. The bar is then free to, move rearwardly under the pull of its spring 514 and withdraw the wedge 517 from pin 519 so that bar 520 can slide to the left and release the bell crank 522. Visibly indicating the performance of an abnormal subtraction. The link 508, moved towards the rear and retained in that position throughout, an abnormal subtraction operation, is connected by a collar 537 and pivoted yoke 538 with a vertically slidable bar 500 adapted when raised to expose a sign such as the letters " O.D." to indicate that an overdraft is in the machine. This sign remains visible until the, following operation with the " P " key depressed,. since the release of the machine by the use of the error key 544 does not affect the position of levers 509, 505 and link 508. Alternative release of machine by additional motor bar. When it is desired to release the machine and at the same time to disable the tabulating mechanism for single column work, a second motor bar 570 is depressed. This bar is supported by arms 571, 572 the latter of which has an upstanding arm 572<a> connected by link 576 with the tabulating mechanism. The rear part 572<b> of the arm 572 is connected by a pin and slot and link 579 with the rear end of the motor release lever 522. The arrangement is such that, motor bar 79 ma.y be depressed without affecting the motor bar 570 and vice versa, the lever 522 in each case being depressed to start the motor. Specifications 18320/08 and 18321/08 also are referred to.