Patent GB-190810119-A (GB)
Title: Improvements in or relating to Calculating Machines
Inventor: TODD JAMES GUICHARDE
Filed: 1908-05-09
Granted: 1909-05-06
Abstract: 10,119. Todd, J. G. May 9. Calculating - apparatus; counting - apparatus; ticket clips and punches.-In calculating-apparatus employing manually operated sliding members which are moved distances proportional to the amount to be added or subtracted, means are provided for adapting the apparatus for computations in different scales, and the application of the device to ticket-punching apparatus is described. The apparatus comprises a series of weight-controlled rack-bars B, Figs. 1 and 3, suspended in an approximately vertical frame, each rack-bar being provided with an adjustable plate E' bearing a catch or projection E and index-plate F. Each index-plate carries two vertical columns of figures as shown, the left-hand columns being used for addition and the right-hand for subtraction, the resultant figures of one or other set appearing in the recesses G<1> of a sliding plate H. In operation, a stylus is inserted between the teeth of one of the computing-bars B by the aid of fixed index-plates J, and moved downwards into contact with the cover-plate H. Backward motion is prevented by the pawl B<5>, Fig. 8, carried by the frame. Carrying is performed by the tappet B<6> of one bar coming into contact with and driving the weightcontrolled suspended tappet-plate C which carries the pawl C<1> engaging the rack of the next higher computing-bar, the slot C<5> in the tappet-plate which engages the pivot of the pawl B<5> allowing motion to the extent of one tooth of the bar only. At the limit of movement of the computing-bar, e.g. when a total 10 is reached, the pin B<7> operates the weight-controlled pawl-releasing bar D, Figs. 4 and 5, shoulders D<6>, D<7> of which disengage the pawls B<5>, C' respectively from the bar B which is then returned to normal position by its controlling- weight. The bar D is held in its releasing position by the friction between its spring D<8> and the bar A<10> of the frame until it is returned to normal position by the projection E on the computing-bar engaging the pin D<5>, but, should a number, say 7, be added to a number, say 5, thus making a total greater than 10, the computing-bar reaches the limit of its movement, as determined by the transfer tappet B<6> and tappet plate C, when the stylus is the space of two teeth distant from the cover-plate H, and on the return of the computing- bar, in which the stylus is left inserted, the stylus strikes against the projecting lower end of a stopplate N adjustably secured to the bar D by a nut D<10>, restoring the releasing-bar and allowing the pawls B<5> and C' to engage with the computing-bar at a point the space of two teeth lower than would have been the case if the projection E had been allowed to engage the pin D<5>. The number 2 on the lower bar is thus exposed to view through the opening G', and the position of the next higher bar, the reading of which is 1, is unaffected by the return of the lower bar. A positive lock for the pawl-releasing bar D in place of the friction lock is shown in Fig. 11, and consists of the weighted or spring-controlled latch M, the pin M<5> of which engages in the notch D<3*> of the bar D on its depression by the pin B<7>. On the return of the computing-bar, the projection E engages the face of the cam M<4> on the latch and rocks the latch until the pin M<5> is clear of the notch D<2*>, when the projection E engages the pin D<5> of the bar D and restores the latter to normal position. As before, when e.g. the total of two numbers is greater than 10, the stylus, which is left inserted in the computing-bar, engages the shoulder M<8> of the latch M and frees the bar D. Calculations in different scales may be performed by altering the position of the adjustable projection E which is controlled by the claw E', and so altering the point at which transfer takes place. To zeroize the apparatus, a bar K, Fig. 1, normally supported by springs is depressed by means of the thumb-pieces K<1> at its ends and engages pins K<3> at the lower ends of all of the computing-bars, which are carried downwards to the full extent of their movement, thus operating the pawl-releasing bars D and disengaging all the pawls from the computing-bars. The bar K is then released and all the computing- bars travel back together to their zero positions. As at each depression of a tappet bar C its computing-bar will be displaced through the space of one tooth, the apparatus may be used as a counter, in which case a tappet-bar on the extreme right may be provided with a projection extending through the cover H<1> whereby it may be readily operated. This tappet bar may be combined with a ticket punch. Springs may be used instead of weights to control the rack-bars &c., and the apparatus may be disposed in a horizontal position.