Patent GB-621390-A (GB)
Title: Differential setting mechanism for the indicating wheels of cash registers and the like accounting machines
IPC: G06C11/02
Filed: 1946-04-26
Abstract: 621,390. Cash registers. CENTRE D'ETUDES M.B.A. (MECANIQUE, BALISTIQUE, ARMEMENT). April 26, 1946, No. 12590. Convention date, Feb. 9, 1945. [Class 106 (il)] Differential setting mechanism for the indicating wheels of cash registers and similar accounting machines, comprises a plurality of selecting units, each of which corresponds to a row of keys of the same denominational order, characterized in that each unit comprises a driving member which has a drive-transmitting connection with a stepped cylindrical cam, through a ball and a locking cam, the latter being fixed to a second and similar cylindrical stepped cam, the said cylindrical cams being capable of a slight relative rotational movement as the operation of the mechanism is initiated to bring the locking cam into engagement with the ball and thereby positively lock the said drive-transmitting connection. Each selecting unit, Fig. 4 and 6, comprises a driving disc 11 on a hollow shaft 12 and three disc plates 8, 14 and 14<SP>1</SP>, which are riveted to one another and carried by a sleeve 13 loose on the shaft 12. Integral with the intermediate disc 14 is a stepped cylindrical cam 16 inside of which is a similar stepped cylindrical cam 17 carrying a locking cam 18 which co-operates, as described later, with a ball 19 located in a recess 20 in the cam 17, in a hole 21 in the disc 141 and in a sloping guideway 22 in the disc 11. Normally the cam 18 is out of engagement with the ball 19, Fig. 12. A spring 23, having one end fixed to a pillar 24 on the disc 14<SP>1</SP>, encircles the sleeve 13 and bears against the cam 18, urging a pin 34 against one arm of a lever 32 carried by a setting member 25, Fig. 6, rigidly secured between the two discs 8 and 14<SP>1</SP>. The member 25 has a recess 26 which is engaged by the tail 27 of a  tongue 28 against which the other arm of the lever 32 bears. Secured to the disc 141 is a wheel 36 which meshes with a toothed wheel 37, Fig. 1, on an indicating wheel 38 visible through an opening 39. The discs 8 and 14 and the member 25 are provided with recesses 40 normally engaged by the forward end of a release lever 9. On a drive shaft are two toothed wheels 41 and 43, Fig. 9, the latter being driven either directly from a hand-crank 44 or from an electric motor through a pinion 45 on a shaft 56. Between the crank 44 and the wheel 43 is a plate 48 urged counter-clockwise by a spring 49 and engaging with play a stud 50, not shown, on the wheel 43. The wheel 43 meshes with a transmission wheel 54, which in turn meshes with a wheel 55 loose on the shaft 56. The pinion 55 is rigid with a wheel 57 having teeth over half its periphery and the wheel 45 is rigid with a wheel 58 also provided with teeth over half its periphery. The wheels 57 and 58 mesh alternately with the wheel 41. Depression of a key on the keyboard causes, as described in copending Specification 617,346, a corresponding bar 1, Fig. 1, to rise inside the cams 16 and 17 and the release of corresponding unit 2. Rotation of the wheel 43, Fig. 9, causes through the plate 48 and the lever 52 the rocking of all the levers 9 to release all the units 2. Continued rotation of the wheel 43 for two revolutions causes through the above-described gear train one clockwise revolution of the wheel 41 and one counterclockwise revolution thereof. Upon the release of the particular unit 2, the disc 14<SP>1</SP> and the member 25, Fig. 10, move until the member 25 abuts the tail of the member 28, Fig. 12, during which movement the lever 32 is rocked counter-clockwise by the action of the spring 23 and the stud 34. This movement of the lever 32 effects a relative movement of the cylindrical cams 16 and 17 to lock the cam 18 against the ball 19. The disc 11 then continues to drive the complete unit 2 until the cams 16, 17 are arrested by their appropriate steps engaging the raised bar 1. The latter part of the rotation of the cam 16 is effected relatively to the cam 17 severing the lock formed by the cam 18 and the ball 19. During this rotation the indicator wheel 38 is brought to the corresponding position. The various components of the unit 2 are brought back to their initial positions during the reverse rotation of the disc 11.