Patent GB-189808542-A (GB)
Title: Improvements in Arithmometers and in Printing Mechanism therefor.
Inventor: CLIFFORD CHARLES CONDIT
Filed: 1898-04-12
Granted: 1898-11-26
Abstract: 8542. Clifford, C. C. April 12. Type-writers and like machines.-Relates to apparatus for adding and multiplying and printing the process and its result. A series of rows of spring keys B<1> are mounted in a carriage B which can be pushed forward on rollers a, a to effect the registration after the amount to be added has been set up by depressing the keys. When any key is depressed it is held by a spring bar B<3>, Fig. 8, engaging a shoulder b<1> until the return of the carriage, when a slotted bar B<4>, which is so shaped at its end B<6> that it slides under and lifts an abutment in the forward movement, but is thrust to the right by it in passing back, releases all the locking-bars B<3> and allows the keys to be returned to normal position by their springs. In its forward stroke the depressed key in each row strikes one of the steps c on the plate C and moves this plate, and with it the sliding rack bar D, a distance proportional to the value marked on the key, giving a corresponding rotary movement to the registering-wheels D' through the pinions D<1> and a connecting pawl and ratchet. The wheels are not returned with the racks, being held by detents D<6> acting on scallop wheels D<5>, so that each sum set up on the keys is added on the register. Where repeated addition of the same number is required, as in multiplying, an arrangement is provided by which the key-returning mechanism does not act till the required number of strokes has been given. This consists of a dial with 9 teeth turned by hand a distance proportional to the number by which it is desired to multiply ; the dial holds the abutment for the key-releasing bar B<4> out of action until it is returned to normal position, one tooth at a time, by the repeated movement of the carriage. The apparatus is actuated by a lever, not shown, linked to a frame G which is normally locked to the carriage B by a spring latch I<1>. When the complete forward stroke has been made, the projections I<2>, I<3> meet, releasing the frame G (which can travel still further) and engaging the latch I' with the bar P so as to retain the carriage till the return of the frame. A rack and automatically-reversing pawl ensure the complete stroke of the frame. The 'carrying' mechanism of the counter consists of a series of pawls K<3> mounted on spring levers K<1> with latches K' engaging a cross-bar K<5>. Whenever a wheel of the counter passes its zero below the exhibition slit L<1>, a pin J releases the latch K' of the next higher wheel, whereupon the lever K<1> swings so as to engage the pawl K<3> with the next tooth of a ratchet-wheel D' and bring a pin k in front of the pawl I on the frame G. At the next stroke of the frame the lever is returned, moving forward the wheel one unit and re-engaging the latch. While the 'carrying' is incomplete a counterweighted shutter L is moved over the slit L<1> by projections L<2> on the pawls K<3>, and indicates that the carriage must be actuated till the levers K<1> are returned to normal position. The shutter then falls back into place, and the result is displayed. A pneumatic dash-pot is provided to prevent shocks. Sliding type-bars M, Fig. 1, are connected to the stepped plates C so as to be adjusted with them. At each actuation of the apparatus, the lever R<1>, carrying the inking-frame R, is drawn back, the roller N<8> running over a pivoted guide N<6> forced upwards by a spring N'. When the roller is clear of the guide it rises, and with it the paper guide N, and a spring trigger O is then released by a slip pawl, not shown, and takes the impression by means of platens p on spring fingers P. In the return stroke the trigger is drawn back, the paper guide depressed, and the paperfeed roller N' turned by the ratchet N<7> and fixed pawl N<9>. A slight play is given between the stepped plates C and the rack-bars D to allow of the printing of the zeros, say in such numbers as 500, without moving the rack bars and so the register. For this purpose means are provided to give a slight movement to all the stopped plates to the right of any depressed key, so as to bring the zero of its type-bar into printing position. Catches U<3>, U, Fig. 1, may, by moving a thumb-lever, be brought respectively over the trigger 0 and frame R and prevent the action of the printing-mechanism. Also, by rocking the lever S, Fig. 3, the racks D may be thrown out of engagement with the pinions D', and the register prevented from acting.