Patent GB-221167-A (GB)
Abstract: 221,167. Haddan, A. J. H., (National Cash Register Co.). May 30, 1923. Adding-machines ; statistical machines; cash registers ; differential mechanism.-In differential mechanism of the type comprising an invariably moved driving segment and a differentially movable segment adapted to be coupled by means of a latch, each differential segment is provided with an arresting projection adapted to engage a notched plate on the corresponding totalizeractuating rack to lock the rack against rebound from its invariable terminal position whereupon the teeth of the differential segment are disengaged from the rack. The differential segment has a slotted or notched connection with the driving segment so that the latter may move in advance of the differential segment to allow the latch to couple the segments. The differential mechanism, as shown applied to a record-controlled machine for compiling statistics as described in Specification 221,255, comprises, for each totalizer shaft, a constant-excursion driving member 213, Figs. 1 and 6, secured to an oscillatory shaft 190, a differentially movable member 214, and a latch member 219, 220. The latch member, which is pivoted at 218 to the differential member, is under the control of a spring 222 and has pivoted thereto one end of a rack 215 the other end of which is slotted to engage a pin 217 on the differential member. During the initial counterclockwise movement of the shaft 190 the latch is rocked so that a projection 223 on the latch arm 220 enters a notch 231 on the member 213; during the further movement of the member 213 a notch 229 thereof engages a pin 230 on the differential member and causes it to move therewith. On the return movement of the shaft 190 the differential member is carried along with the driving member until a corresponding electromagnet 238 is energized by the perforations on the record sheet as described in the abovementioned Specification whereupon the lever armature 235 is rocked to permit the plate 236 thereon to engage a tooth of the rack 215. This mechanism may be controlled by other means such as depressed keys. The pin-and-slot connection of the rack with the differential member allows the latch to rock to disengage the projection 223 from the member 213 which completes its movement, the differential member 214 being held in the adjusted position by a projection 224 on the latch arm 220 engaging a tooth of a fixed rack 225. If no electromagnet is energized the movement of the differential member is arrested by a pin on the rack 225 engaging the end 227 of the rack 215. Each differential member 214 carries a link 248 pivoted to one end of a beam 247 the other end of which is pivoted to a plate 245 secured to a hub 243 loose on a shaft 198; the hub 243 has secured thereto a segment 244 which engages a rack 181, Fig. 8, slidable on a plate 184 and provided with a hooked lever 179 engaging a pin 177 on the totalizer shaft 176 whereby the lateral movement of the shaft is effected to select the totalizer. The movement of the beam 247 is controlled by a " minimum movement " device constituted by an actuator 250 fixed on a shaft 188 and having a pin 251 engaging the beam 247. The plate 245 is provided with a toothed portion 252 with which co-operates an aligning pawl 253 secured to a shaft 189. The shafts 188, 190 are rocked by means of pairs of cams actuated by gearing from a drive shaft 154. Each differential-selecting mechanism is associated with two banks of contacts similar to those described in Specification 185,075. The differential mechanism for the totalizer actuating racks 277, Figs. 13 and 14, is substantially identical to that described above for totalizer selecting but in the contact banks two short contacts are located between the " L0," "L1 " and the " R0," " R1 " contacts. Integral with each differential actuating member 214 is a segment 299 that engages a corresponding rack 285 associated with a pair of totalizer actuating racks 277 and provided with a notched plate 301 that cooperates with an arresting projection 300 on the segment 299 and which is so arranged that when the teeth of the segment are disengaged from those of the rack 285 the outer surface of the said projection 300 bears against the cut-away portion 302 of the plate 301 and serves as an aligner to hold the rack in its end position. The short contact 274, before mentioned, is placed between the " 0 " and " 1 " contacts to increase the travel of the segment 299 on the return movement to ensure full engagement between the teeth to limit the play of the rack. The shaft 294 to which the driving member 213 is secured carries a segment that gears with another segment adapted to be rocked by a pair of cams actuated by rotation of the main shaft 151.