Patent GB-190815094-A (GB)
Title: Improvements in or relating to Calculating Machines.
Inventor: LEMAIGNEN ROBERT BERTIN AUGUST
Filed: 1908-07-16
Granted: 1909-07-15
Abstract: 15,094. Lemaignen, R. B. A. July 16. Calculating-apparatus. - In a keyoperated calculati n g - machine, a n indicator consisting of a single drum or sector is provided, which shows at each operation of the machine the amount registered during that operat i o n , and thus forms a check for the operator upon the key struck, and the completeness or otherwise of its stroke. The invention is shown as applied to the adding-machine described in Specification No. 15,095, A.D. 1908. The depression of a key o f t h e machine rocks the shaft 9', Fig. 3,thereby rotating the ratchetwheel a, fixed thereto, which drives the spring- controlled plate b, loosely pivoted upon the shaft 9', by means of the pivoted pawl a<1>. A tappet g<1> fixed to the pawl a<1> is adapted, upon the rotation of the plate b, to engage with a corresponding tappet g<2>, Fig. 2, upon a spring - controlled pawl e<1> and to raise it out of engagement with the ratchetteeth e of a spring- controlled sector-plate c, which is adjacent to the plate b and loosely pivoted upon the shaft 9<1>. The pawl el is thereupon held by the spring-controlled catch e<3> fixed to the shaft 17, and the plate c, being released, rotates in a clockwise direction under the action of its spring c' until the pin f<2> meets the pin f upon the plate b, whereupon the plate b carries round the plate c in the opposite direction. The depressed key is adapted at the end of its downward stroke to rock the shaft 17, thereby releasing the pawl e' which re-engages with the teeth e and holds the plate c in the position to which it has been carried by the plate b. The shaft 17 also carries an arm i which, striking a pin i<1> upon a lever h pivoted at h<1>, causes the lever to wipe the pawl a<1> out of engagement with the ratchet-wheel a by means of a pin h<2>, and so allows the plate b to return to its original position as determined by the stop b<2>. A toothed wheel d<2>, attached to an indicating drum d' gears with teeth d upon the plate c, and thus causes a figure to be displayed by the drum corresponding to the actual rotation imparted by the key to the shaft 9<1>. If a key be depressed insufficiently to rotate the shaft 17, the catch e<3> will remain in engagement with the pawl e\ and the lever i will not be operated to disengage the pawl a<1> from the ratchet-wheel a. The plate b will consequently not be restored by its spring b<1>, but will hold the sector-plate c in the position it has reached by means of the pins f<1>, f<2>. At the next operation of the machine the number corresponding to the rotation given to the shaft 9<1> will be added upon the indicator to the number already shown thereon, and the figure displayed will be greater than the value of the depressed key, or, if the sum of the two numbers be greater than the number of teeth e upon the plate c, the whole machine will be brought to a standstill by this plate striking the stop b<2>. In this case, the spindle 17 may be rotated by means of an external driver (not shown) to release the pawl a<1> and plate b. When the same key is operated twice running, and the second depression takes place before the key has completed its full upward stroke, then the rotation imparted to the shaft 9<1> in the two cases differs, and the numerals successively shown by the indicator will differ also. In a modification, shown in Fig. 4, the tail of the pawl a' bearing the tappet g<1> is replaced by a pivoted arm j provided with a cam-shaped projection k<1>, which is adapted to engage a correspondingly-shaped cam-piece k<2> on the pawl e<1> and disengage the pawl from the sector-plate c, as before, in one direction of rotation, and in the other to slide over and be raised by the cam-piece k<2>. In the form shown in Fig. 6, the plate c is adapted to act directly as the indicator, a blade l suitably numbered being attached thereto.