Patent GB-611539-A (GB)
Title: Improvements in or relating to cash registers and similar accounting machines
IPC: G06C7/10
Filed: 1946-03-21
Abstract: 611,539. Typewriters &c. NATIONAL CASH REGISTER CO. March 21, 1946, No. 8767. Convention date, July 21, 1944. [Class 100(iv)] [Also in Group XIX] A calculating machine has linearly-reciprocating totalizer-actuating racks positively driven in both directions and gear wheels between the racks and a printing means, the axis of each gear wheel being moved by a member having a constant excursion to transmit the setting of the racks to the printing means, the arrangement being such that the printing means are moved directly from one setting to the next without first returning to an initial position. This mechanism for driving the printing means is called a " minimum movement mechanism." Differential mechanism. A key-stopped slide 124, Figs. 2, 7. is geared to the totalizer-actuating rack 135 which is driven to the left by a pin 141 engaging an inclined slot 140 in the rack and protruding from a differential latch 142, Figs. 5, 11, pivoted to a latch slide 143. The differential latch has a tooth 147 engaged by a shoulder 148 in a driving plate 149 reciprocated by a cam on the main shaft. As the driving plate 149 moves to the left, it takes with it the differential latch 142, the latch slide 143 and, by the pin 141, the actuating rack 135, until this last is stopped by the engagement of a lug on the key-stopped slide 124 with the stem of a depressed amount key 72. The inclined slot 140 in the rack 135 forces the pin 141 upwards to rock the differential latch 142 to disengage the tooth 147 from the shoulder on the driving plate 149, this last then continuing its movement, the latch being retained in this disengaged position by a ledge 148 on the edge of the driving plate. A latch-retaining plate 145, Figs. 7, 11, is connected to the rack 135 by a spring 146 and a slot 144 which pushes the pin 141 and the differential latch 142 back to normal position. The latch slide 143, differentially positioned as described above, drives printing wheels through a " minimum movement mechanism " which moves direct from one setting to the next without first returning to an initial position. A beam rack 188, Fig. 5, is slidably carried on upward, extension 189 of the latch slide 143 and is moved one step left relative to the latch slide as the latter makes its initial movement left by a lever 192 pivoted on the latch slide and operated by a roller 217 engaging a fixed cam track. The beam rack 188 meshes with a beam gear wheel 194 pivoted to a beam slide 196, Fig. 6, connected by a link 197 to a pivoted arm 198. The beam gear 194 also engages a printing- wheel positioning rack 203. Differential movement to the left of the latch slide 143 and beam rack 188 rolls the beam gear over the printing-wheel positioning rack 203, the beam slide 196 carrying the gear also moving left until a face 202 on said beam slide 194 engages a fixed member 156. Further movement of the latch slide 143 drives the beam gear to drive the printing- wheel positioning rack 203. If the beam slide 196 has not reached the fixed member 156 when the latch slide 143 is differentially arrested, the movement of the beam slide 196 is completed by the engagement of a pin 201, Figs. 5, 11, on the next higher driving plate 149 with the pivoted arm 198, Fig. 6, linked to the beam slide, the beam slide and the axis of the beam gear thus having a constant excursion. The latch slide 143 is returned to its initial position by a stud 176, Fig. 5, on the driving plate 149 as the latter makes its return stroke to the right, the beam gear 194 rolling over the printing-wheel positioning rack and leaving this in its adjusted position. Printing mechanism. The printing-wheel positioning rack 203, Fig. 2, drives a toothed ring 206 geared to a type wheel 209. Internal teeth on the ring engage a pinion 215 on a shaft 216 to which is fixed a second pinion meshing with a second toothed ring which positions a second type wheel to repeat the printing in a further column. Control of zero printing. The lever 223, Fig. 12, connected to the beam rack 188 for the highest denomination and pivoted to the highest latch slide (not shown) has a pin 224 underlying a zero latch 227. If no digit is set in the highest denomination, the latch slide and lever 223 move a small step left but the zero latch 227 still overlies the pin 224 and the beam rack 188 does not move far enough to bring a zero to the printing position. If a digit is set, the pin 224 moves left from beneath the zero latch and the lever 223 is rocked anti-clockwise by the action of a fixed cam (not shown in ,Fig. 12) on the pin 224 to shift the beam rack to initial printing position. The pin 224 also rocks clockwise a latch 233 which rocks counter-clockwise the lever 192 connected to the beam rack (not shown in Fig. 12) of the second highest denomination, thus positioning the rack to zeroprinting position. A pin 217 on this second lever 192 similarly moves the beam rack of the next lower denomination to zero-pointing position, and so on. If, say, the third highest denomination is the highest one containing a digit, the zero latch 227 retains the two highest beam racks in non-printing positions.