617,346. Cash registers. CENTRE D' ETUDES M. B. A. (MECANIQUE BALISTIQUE ARMEMENT). April 26, 1946, No. 12589. Convention date, Jan. 27, 1945. [Class 106 (i)] Key-operated mechanism for cash registers and similar accounting machines, comprises a keyboard, the keys of which are arranged in a plurality of rows extending from the front towards the back of the machine, each row of keys being associated with a complementary system of bell-crank. levers disposed in the same plane as the key row, and each of said levers being operable by a complementary key and being positively connected to a complementary setting member, characterised in that the bell-crank levers and the adjacent portions of the setting members are made of sheet metal and that the said adjacent portions are located in the same plane as the bell-crank levers, the levers and the adjacent portions being located between two guide plates and being.pivotally connected together between the said plates, a slidable bar being located externally of, and in contact with, each guide plate and being so constructed that when any one key of a row is depressed, the said bars are disposed to lock the remaining keys of the row against depression. The keyboard includes a series of keys 1, each of which, Fig. 4, is longitudinally slotted at 2 to engage one end of a bell-crank lever 3, Fig. 5, pivoted on a ball 9 housed in a recess 10 between two plates 7 and 8 enclosed in a casing formed by two flange members 11 and 12. The other end of each lever 3 engages a notch 4 in a flange 5 of a transmission bar 6. The flange members 11 and 12 are shaped to provide for the passage of sliding bars 13 and 14 which, as described later, when a key is depressed lock the other keys of the same row and at the end of a machine cycle return the depressed key to its initial position. The rear end of each bar 6 is forked, Fig. 2, the downwardly extending part 17 resting on a roller 18 having flanges 21 at the ends of each group of bars 6 and the upwardly extending part 19 co-operating with the differential setting mechanism as described in Specification 621,390. The bars 6 are constantly urged into the position shown in Fig. 2 by a roller 22 on an arm 24 urged counterclockwise by a spring 23. Each key is provided with a stud 30, Fig. 7, which co-operates with a sloping part 29 on the sliding bar 13 and a stud 32 which co-operates with a notch 31, Fig. 8, on the sliding bar 14. The arrangement is such that when a key is depressed the bar 13 is moved to the right, Fig. 2, and through a double armed lever 27 the bar 14 is moved to the left. In this position the stud 32 on the depressed key is engaged in the adjacent notch 31 so locking the depressed key. At the same time the tops of the bar 14 between the recesses 31 prevent depression of any other key in the row by engaging the studs 32. When the bar 13 moves to the right a pin 36 thereon rocks a lever 37, 39 clockwise to release for rotation a disc 40 of the differential setting mechanism. Depression of a key has also caused, through the associated bell-crank lever 3 and associated member 5, the corresponding transmission bar 6 to move to the left and by means of the engagement of the roller 18 and the part 17 the part 19 is raised into the position in which it co-operates with the differential setting mechanism as described in the above copending application. At the end of a machine cycle a tooth 42 on the disc 40 rocks the lever 37, 39 further clockwise and the arm 37 engages a pin 43 on the bar 14 to reset said bar 14 to its initial position and through the double armed lever 27 the bar 13 is also moved to its initial position and the depressed key is reset by the action of the slope 29 on the pin 30 of the key. The axis 38 of the lever 37, 39 may be provided outside the casing with a key actuation of which, by hand would reset all depressed keys. Each bell-crank 3 has a projection 44 which cooperates with the stud 32 of the adjacent lefthand key to prevent simultaneous depression of two adjacent keys. Each bar 14 has an extension which projects through the front of the casing so that any bar 14 may be manually reset after a "wrong" key has been depressed. A bar 50 is adapted to be operated by the key of the cash drawer and has recesses 49, Fig. 12, co-operating with levers 47 connected to each bar 14 so that said bars 14 may be locked against operation.