509,042. Calculating-machines ; typewriters etc.; ink - ribbon mechanism. NATIONAL CASH REGISTER CO. Oct. 8, 1937, No. 27360. Convention date, Oct. 8, 1936. [Class 106 (i)] [Also in Group XVI] A calculating-machine comprising an adding and subtracting totalizer has means for converting a complementary overdraft into its true negative form and printing a subtotal of said true negative form in a distinctive colour during a single operation and means, conditioned during this operation and operative when the totalizer is selected for obtaining a repeat print of the true negative overdraft in a subsequent operation, for causing this repeat print to be in the same distinctive colour. The overdraft conversion and subtotal-taking are effected during a single operation of three cycles. At the end of this operation the overdraft is left standing on the totalizer in true negative form. Other operations involving printing may then be performed on the machine but the printing mechanism remains conditioned as stated above until the said totalizer has again been selected. The invention is shown applied to a machine of the kind described in Specifications 28253/08, [Class 106], and 420,807. Starting machine in normal operations. The machine is started by depressing a starting bar which operates the starting mechanism described in Specification 497,640. Starting machine in overdraft subtotaltaking operations. Depression of the overdraft subtotal key 77, Fig.7, operates, by means of a link 106, the starting mechanism referred to above. A latch 108 moves under spring action over an ear 107 on the stem of the key 77 to hold the key depressed, the latch being con nected by a link 117 to a lever 118 which is thus rocked clockwise to release a detent 120 to engage a stud 110 in the starting mechanism. This prevents the machine being automatically stopped at the end of one cycle. During the third cycle, a cam 122 on a control-cam-shaft 86 restores the lever 118 to release the key 77 and the stud 110 so that the machine stops at the end of the third cycle. Control cams. Depression of the overdraft subtotal key 77, Fig. 20, by means of a pawl 135 rocks a ratchet wheel 137 secured to the control-cam-shaft 86, the shaft being rocked sufficiently to allow a cam 134 thereon to move past a stud 133 on an arm 131, the said arm then being rocked clockwise by a spring 136. A pin 140 on the stem of the overdraft subtotal key 77 lowers a coupler 141 into engagement with a stud on a slide 145, the coupler being pivoted to a crank 142 on the main-shaft 78 so that the slide is reciprocated as the mainshaft is oscillated. Pawls 146, 147 on the slide 145 operate the ratchet-wheel 137 to turn the control-cam-shaft 86 through one rotation during three complete oscillations of the mainshaft. Printing mechanism. The printer shaft 128, Fig. 7, is oscillated from the-main-shaft 78 by means of a printer-operating link 125 normally latched over a stud 124 on an arm 79 secured to the main-shaft. Each type sector 68, Fig. 4, is positioned by a link 180 connected to a segment 171 operated by a differential actuator 166. Initial clockwise rocking of the printer shaft 128 increases the tension in springs 185, each stretched between a bail 213, 211 secured to the shaft and a pawl 210 pivoted on a respective arm 181 free on the printer shaft. A latch 182 later releases a plate 184 connected to the arm 181 whereupon the spring 185 rocks the arm 181 clockwise to bring the type 68 against the platen 67. Preventing printing of zeros. Azero-elimination pawl 186, 190' detains the plate 184 unless the segment 171 moves from zero position, a pin 189 on the segment then engaging the tail 190 of the pawl to rock it to inactive position. The pawls are connected by overlapping devices to operate all pawls below the highest active one. The one-cent and ten-cent pawls are permanently connected. Releasing depressed amount keys. Means similar to those disclosed in Specification 497,640 are described for releasing depressed amount keys at the end of entering operations and at the beginning of total-taking and subtotal-taking operations. Overdraft subtotal-taking operation. Depression of the overdraft subtotal key starts the machine and rocks the control-cam shaft 86 anticlockwise, Fig. 6, as described above to move a control cam 394 past a roller 395 on an arm 296, said arm then rocking clockwise to rock clockwise through connections 397, 398, 406, an arm 400 which engages a pin 801, Fig. 16, on the lower part of a two-part latch 735 and rocks this part anticlockwise so that its end engages known mechanism 737 to cause the totalizer to be engaged in total-taking timing. During the first cycle, the complementary overdraft is withdrawn from the totalizer and entered into a storer as described in Specification 420,807. During the second cycle, the high part of the cam 394 operates mechanism (not shown) to engage the totalizer in subtractive timing so that the amount is taken from the storer and subtracted from the totalizer, this latter then holding the true negative overdraft. At the beginning of the third cycle, the cam 394 again allows the arm 400 to rock to engage the totalizer for total-taking, but during this cycle the cam moves the arm to allow the latch 735 to release the known mechanism 737 so that the totalizer remains engaged during the return of the actuators and a subtotal of the true negative overdraft is thus obtained, the said true negative overdraft remaining in the totalizer. Overdraft total-taking operation. A total of the true negative overdraft can now be taken by depressing the balance key 73 which, through its latch 735 operates the known total-taking control 737 and, through a lever 740 connected to the latch, rocks a shaft 409 to start the machine by means of an arm 742, Fig. 7. Disabling printing mechanism. The printing mechanism is disabled during the first two cycles of an overdraft subtotal-taking operation. The arm 131, Fig. 7, rocked clockwise upon depression of the overdraft subtotal key moves to the right a link 129 which unlatches the printer-operating link 125 from its driving stud 124. The arm 131 is restored by the cam 134 at the end of the second cycle, the printeroperating link 125 being relatched with the stud 124 to cause printing during the third cycle. Printing overdraft subtotal and repeat print of said subtotal in a distinguishing colour. Ink ribbon mechanism. The ink ribbon 50, Fig. 15, is raised to black-printing position by an arm 639 on the printer shaft 128 which moves to the left a link 641 to rock clockwise a cranked lever 636 connected by a link 635 to a ribbonlifting lever 633 pivoted at 634, the black position being defined by the engagement of a stud 643 on the cranked lever 636 with a catch 644. The catch 644 can be moved to ineffective position by the clockwise rocking of a colour shaft 647, the cranked lever 636 then being allowed to rock a greater distance clockwise to lift the ribbon to red-printing position. The colour shaft 647, Fig. 16, is rocked to this red position when the balance totalizer is selected for subtraction. A link 652 is pivoted to the subtraction-control lever 420 to rock clockwise a bell crank 653 having a link 655 which lowers a pull-rod 657 into the path of a stud 666 on the totalizer-engaging link 430 so that, when this link moves to the left, the pull-rod 657 is moved with it and rocks the colour shaft 647 by means of a crank 658. The colour shaft is restored to black position by means operated by the printer shaft and described in Specification 497,640. An overdraft subtotal is printed in red by the following means. A link, 714, Fig. 7, is pivoted to an arm on the colour shaft 647 and is normally lifted at each operation by a pin 713 on an arm on the printer shaft 128 so that the end 716 of the said link 714 is clear of a pin 717 on an arm 164 rocked clockwise at each cycle. During the first two cycles of an overdraft subtotal-taking operation, the printer shaft 128 is disabled as previously described and the link 714 is thus moved to the right to rock the colour shaft to red position so that the overdraft is printed in this colour during the third cycle. The link 117 which releases the overdraft subtotal key latch 108 moves to the left a link 719 which rocks a bail 722, Fig. 9, freely mounted on the colour shaft 647 so that the end of the bail is latched by a latch 723 secured to a shaft 724 carried in a frame 725 also free on the colour shaft 647. The frame 725 is connected by a link 726, Fig. 21, to the balance-totalizer engaging cam 727 so that the next time the balance totalizer is selected for operation, for example, to take the overdraft total, the clockwise rocking of the frame 725 rocks the bail 722 by means of the latch 723 so that an arm 730 secured thereto moves to the right a link 732 to engage and shift a pin 745 connected (by means not shown in Fig. 21) to the colour shaft 647 whereby this shaft is rocked to red position. The link 732 also positions a printing sector 750 to print a symbol against the overdraft total. The latch 723 is released by a link 759, Fig. 7, pivoted to the arm 164 rocked at each cycle, the link abutting and rocking a crank 763 on the shaft 724 after the bail 725 has been rocked clockwise by the link 726 connected to the totalizerengaging cam. Counting number of subtractive items. The machine is provided with the means described in Specification 506,500 for counting the number of subtractive items. Control of item-counting mechanism during overdraft subtotal-taking. Depression of the overdraft subtotal key first causes the controlcam-shaft 86, Fig. 6, to rock anticlockwise as described above, this rocking allowing the roller 395 on the arm 296 to move on to the low part of the control cam 394, the arm thus rocking clockwise to operate the arm 400 through a connection 397, 398, 406, the arm 400, in addition to co