Patent GB-190906999-A (GB)
Title: Improvements in or relating to Adding Machines.
Inventor: VINCENT JESSE GURNEY
Filed: 1909-03-23
Granted: 1910-03-23
Abstract: 6999. Vincent, J. G. April 6, 1908, [Convention date]. Adding and subtracting apparatus with printing - mechanism. - Adding- machines, especially those of the Burroughs type as described in Specifications 17,126/93, 27,874/03, 20,728/46, and 6114/08, are provided with means for effecting subtraction, such means being rendered operative by the depression of a special key ; with this exception, subtraction is carried out by the operator in the same manner as is addition. During subtraction the registering - wheels are rotated in a reverse direction to that in which they are turned for addition, the usual transfer devices are therefore considerably modified so as to be capable of operation in either direction of rotation of the wheels, and their usual function as zero stops is carried out by additional members. Special type are provided to distinguish totals, subtotals, subtracted items, and those " eliminated," i.e. neither added nor subtracted, and means are employed to ensure a blank stroke of the operating- handle before a totalling or subtotalling operation is performed. Subtracting.-The depression of the subtraction key A lowers the usual pitman 914, Fig. 2, in the same manner as the operation of the total key, but as the foot of the link 911 is now slotted, this depression can be effected without causing the total key or subtotal key to be simultaneously operated. When depressed, the key A is engaged by a detent I, which is, however, disengaged by a pin i<1> on the link 216 when either the total or subtotal key is depressed. The lowering of the pitman causes the registering- pinions 916 to remain in gear with their actuating- racks when these move downwards, but to be disengaged during the upward stroke. Transfer-mechanism.-The transfer pawls 413 are swung rearwards, so as to release the studs 6<c>, Fig. 4, upon the racks 610, by the studs 9 upon the registering-wheels, irrespective of the direction of rotation of the wheels, the lower end of the pawls being provided with a pivoted cam-piece B capable of rocking into two positions. In an adding- operation, the additional upward movement thus given to the racks rotates the corresponding wheels as usual one tooth forwards at the termination of the operation. In subtraction, in which the registering-wheels are disengaged from the racks during their upward stroke, the necessary backward rotation at transfer is given to the wheels while they are engaged with their racks at the restoration of the latter to normal position at the commencement of the ensuing operation. To provide for a continued "borrowing" across the machine in the case of subtraction, simultaneously with the movement of any wheels to zero position studs 9 thereon rock latches E so as to release studs D upon the next lower transfer latches 411. If now the wheels corresponding to these latches rotate backwards through zero, they rock their transfer pawls 413, the latches 411 are pulled rearwards, and their studs D trip the next higher transfer pawls 413 by means of hooks D' thereon. The tripping of transfer pawls thus continues until a wheel is reached the latch E of which has not been rocked so as to allow the next lower transfer latch 411 to undergo its full rearward swing. In this case, however, the movement of the latch 411 is sufficient to lock its transfer pawl so as to permit the corresponding rack to partake of the usual excess upward movement. The latches 411 are restored at the commencement of each operation by a bail 902, which is rocked by a wipe-plate 821<a>, Fig. 2, actuated somewhat similarly to the usual wipe-plate 821. When the subtraction key is released, a toothed hail F<1> is moved rearwards by a pin-and-slot connexion f, g with the lever G and throws the latches E out of the paths of the studs 9 upon the wheels. At the same time, owing to the engagement of a stud h upon the frame of the bail 902 with the lower rear edge of the lever G, the bail is prevented from moving sufficiently far to the rear to allow the studs D upon the transfer latches 411 to engage the hooks D<2> upon the transfer pawls. Distinguishing - marks. - The printing of the special characters is effected in each case by the disabling of the pawl of the additional set of printing-devices, and the consequent release of the corresponding printing-hammer by the cam-edges s, Fig. 10, of an arm 229, which is rocked rearwards by the elimination, total or subtotal, and subtraction keys, whichever one is depressed, by means of suitable connexions. In the first case the arm S carrying the special type and pivoted at its forward end remains in its normal position, Fig. 10. In the second case, the rocking of the key-releasing bail by a link connected thereto turns the arm T, and a roller t thereupon engages the inclined edge of a projection S' and thus rocks the rearward end of the arm S downwards so as to position the uppermost of the three special type opposite the printing- point. In the third case, a lever is rocked by a stud upon the subtraction key, and its rearward foot engaging the roller q rocks the arms 229, 229<a> further to the rear than in either of the preceding cases and pushes the thrust-bar Y so that its camshaped projection y may press a pin y' and thus rock the arm S. The middle one of the three type is thus positioned opposite the printing-point. Printing totals and subtotals.-At the completion of a series of operations, the total and subtotal keys are locked against depression to ensure a blank stroke of the operating-handle by the bails 424, which as usual are moved rearwards on the depression of amount keys by detent strips 214. Where continued borrowing has taken place in an operation in subtraction, and the latches 411 have undergone their full swing to the rear, they prevent the restoration of the bails 424, and thus keep the upper end of the bail positioned beneath a stud 27 on the total key. The restoration of the latches 411 during the next stroke of the operating-handle is followed by the restoration of the bails 424, whereupon the total, or subtotal, key can be depressed. In operations for subtraction, this locking of the total and subtotal keys is only necessary where continued borrowing, i.e. affecting, more than one denomination or bank of figures, has taken place in the last itemizing operation of the machine. The functions of either of these keys is to rock forwards a toothed frame R into the paths of the studs 9 by means of a link r, bellcrank 14<a>, 14<b>, and link 14<c>, and thus to furnish zero-stops for the registering-wheels.