Patent GB-672804-A (GB)
Abstract: 672,804. Calculating-apparatus. NATIONAL CASH REGISTER CO., and WINKLER, M. July 18, 1950 [Sept. 19, 1949], No. 24041/49. Class 106 (i). In an accounting machine having more than one add-subtract totalizer, a mechanism normally co-operative with one totalizer for automatically converting complementary overdrafts into true negative form is adapted also to be effective on another of the totalizers. As in Specification 497,640 conversion is initiated by operating an overdraft or suboverdraft key (not shown), whereupon an overdraft cam assembly, in four successive quarter revolutions, effects four successive machine cycles: (1) in which the complement is cleared from the totalizer and added to a retainer; (2) in which the complement is cleared from the retainer and subtracted from the totalizer to give the true overdraft; (3) the true overdraft is cleared from the totalizer and added to the retainer, and (4) the true overdraft is cleared from the retainer and printed. With the suboverdraft key, the true overdraft is also subtracted from the totalizer during cycle (4) to restore the totalizer to its original state. In Specification 497,640 the conversion mechanism is effective only on the No. 1 or balance totalizer; in the present machine its action can be switched to a No. 3 totalizer by pressing an " overdraft 3 " key 2 adjacent the total key 17 for the No. 3 totalizer. A pin on the key stem then rocks a lever 5 counterclockwise to cam leftwardly an arm 7 hinged at 15 to a hub 100 on a rockshaft 8 so as to switch the arm from the No. 1 to the No. 3 totalizer. During cycle (1), shaft 8 is rocked counterclockwise and a plate 14 on the arm 7 actuates the total key latch 13 for the No. 3 totalizer to set pawls 32 and 33 to condition the No. 3 totalizer for total-taking in known manner. Meanwhile the overdraft retainer is selected to receive the complementary overdraft. In cycle (2), shaft 8 rocks further counterclockwise and a finger 9 thereon rocks a subtract control lever 11 to set the pawls 32, 33 to condition the No. 3 totalizer for subtraction, the retainer is selected for totaltaking and the complementary overdraft thereon subtracted from the No. 3 totalizer which then registers the true negative balance. In cycle (3), shaft 8 rocks back sufficiently to release the finger 9 from the subtract lever 11 whilst maintaining the plate 14 in engagement with the total key latch 13, so that the true negative balance is cleared from the totalizer and added to the retainer. The shaft 8 is then restored to release the key latch 13 and No. 3 totalizer and finally, during cycle (4), the true overdraft is cleared from the retainer and printed in red. When the suboverdraft key is operated, the shaft 8 is again rocked in cycle (4) to cause the true overdraft to be subtracted from the No. 3 totalizer which then registeres the original complementary value. The occurrence of an overdraft in the No. 3 totalizer is indicated by locking of the total key 17 and unlocking of the key 2 by means of a pair of interconnected locking levers (not shown) operated by the totalizer overdraft shaft. When the lever 5 is rocked by operating the key 2, its upper arm 4 displaces a slide 74 and this rocks the overdraft shaft of the No. 1 totalizer so as to free the main overdraft and suboverdraft keys to enable the conversion operation to be initiated. Specifications 395,688 and 420,807 also are referred to.