Patent GB-191113381-A (GB)
Title: Improvements in Calculating Machines.
Inventor: BOOTH HENRY SHEPLEY
Filed: 1911-06-03
Granted: 1912-06-03
Abstract: 13,381. Booth, H. S. June 3. Attachments and connexions to typewriters; adding and subtracting apparatus for monetary values.-Relates to key set and operated computing - attachments for typewriters of the general class to which Specifications 15,709/00 and 9892/02 refer. Differential mechanism; keyboard interlocks. -Depression of one of the typewriter numeral keys draws down the corresponding rod R<1>, Fig. 1, and thence, by a pin-and-slot connexion, a cam-plate C' of which a straight portion C<3> gives differential displacement to an arm A<3>, and thence to a main actuating-sector T<1>. With this cam - plate descends a corresponding guide-plate C<4> and therewith all the other guide-plates, whereupon the springs c of all other rods R<1> force them forwards in the slots of their cam-plates and engage hooks at their upper ends over depending hooked arms C<6>, whereby they are locked against movement. Adding and subtracting; selecting denomination; column-spacing. - There are two masteractuating wheels W<3>, W' mounted in a carriage C<7> adapted, during a prescribed portion of the typewriter carriage movement, to move step by step so as to gear in turn with successive receiving - wheels of the stationary totalizer. Both actuating-wheels are free to slide longitudinally upon their spindles S<3>, S<4>, but the spindle S' is square in order that the wheel W<3> may receive a differential movement upon the return stroke of the sector T', Fig. 8, which first withdraws a pawl P<1> upon the forward stroke, thereby winding a spring, which effects the return movement of both sector and pawl and thus rotates the spindle S' by means of the ratchet-wheel W<2a>. A simple reversing-gear is inserted between the two actuating-wheels upon the carriage, and the selection for addition or subtraction is made by a slight longitudinal movement of the carriage. When the papercarriage arrives at the position assigned to the money columns, lugs P<3>, A<4> engage, and the actuating-wheel carriage is moved to the right under the combined control of a cord d passing over a differential pulley D<2>, a rack R<4>, and pawls P<2>, and when the numeral shift-key is depressed, the paper-carriage escapement rack is thrown out of gear. Transfer mechanism.-Single teeth a on the wheels W<6> engage teeth on wheels W<7> of the totalizer, and give them a slight extra movement which is afterwards corrected by a detent. This mechanism operates equally for addition or subtraction. The wheel W<7> is, however, locked until a lower wheel at the transfer point cams up the lever L', and thus removes a pin thereon from the teeth of the higher wheel. Interlocking; overthrow-preventing mechanism.-The depression of any key draws down the rod R', thereby moving the locking - levers A<6>, L' and allowing the spring detents L<2> to rise. Upon the return of the actuating-sector, the lower arm of the locking-lever L<4> is operated to release the wheel at the actuating point. Means are provided to prevent overrunning of the actuating-train ratchet-wheel W<2a>, and an error-key also co-operates with the same wheel. Varying functions of machine; monetary values, adaptations for. The sector shaft S<2> may be rotated by means of a lever thereon so as to move all the roller-arm levers out of the path of their respective cams and disable the calculating- parts. When the carriage passes into the space for tens-of-shillings, all keys but the ' 1 ' key are automatically locked, and similarly in the tens-of-pence space, in which also the arm A<3> corresponding to the ' 1 ' key is differently connected to the shaft S<2> so as to give an actuation ten times as great. A second pair of actuating- wheels may be added, as shown.