511,438. Cash registers, revolving-barrel locks. NATIONAL CASH REGISTER CO. Feb. 17, 1938, No. 4935. Convention date, March 25, 1937. [Class 106 (i)] [Also in Group XXV] Keyboard mechanism sequence arrangements taking totals and subtotals. A cash register or similar accounting machine is adapted to be conditioned for total or subtotal taking by a key insertable into a lock; full insertion of the key locking the amount keys, and depression of an amount key preventing the full insertion of the key. The invention is described as applied to a machine wherein the kind of operation is controlled by a differential member 36, Fig. 1, positioned by key stems 33, 35 in subtotal and total taking operations. The key stems are now headless and are depressed alternatively upon the rotation of a lock barrel in one direction or the other. Upon the insertion of a key 24, Fig. 6, the barrel is rotatable by the key in counter-clockwise direction only, whereupon a pinion 28 on the barrel, meshing with a rack 29 on a slide 30, shifts the latter downwardly, and by a cam-slot 31, therein, depresses the subtotal key stem 33. Upon the insertion of a key 25, Fig. 5, the barrel is freed for rotation by the key in either direction to shift the slide upwardly or downwardly and thus depress the total key stem 35 or the subtotal key stem 33, respectively. Rotation of the barrel in either direction, by a stud 45 on the slide, rocks a bell-crank 47 clockwise to release the machine. Insertion of either key rocks a crank 52 and, through a slide 54 and link 56, interposes a bail 57 in the path of a series of arms 60, each associated with a detent plate in one of the amount key banks, whereby the amount keys are locked. Conversely, upon the depression of an amount key prior to the insertion of one of the keys 24, 25, an arm 60 is positioned below the bail 57 to prevent the complete insertion of a key 24, 25. Revolving-barrel locks. The lock, Figs. 5 and 6, has a barrel divided into two parts 12, 13 secured-against longitudinal movement by screws 15 and normally held against rotation by pins 19 and tumblers 18. Upon the insertion of key 25, Fig. 5, both parts of the barrel are freed for a rotation by the key of about 90 degrees in either direction, the extent of potation being limited by studs 42 on the part 12 co-operating with a fixed stud 43. However, upon the insertion of key'24, the barrel part 12 only is freed, which part may now be rotated in counter-clockwise direction, rotation in clockwise direction being prevented by an overlapping end part of the barrel part 13.