Patent GB-181043-A (GB)
Title: Improvements in calculating machines
IPC: G06C7/06
Filed: 1921-01-06
Abstract: 181,043. Jackson, W. J. Mellersh-, (Felt & Tarrant Manufacturing Co.). Jan. 6, 1921. Adding and subtracting apparatus with operating-means. - In a power-operated multiplebank keyboard machine applicable for calculating by any of the four rules, the depression of a key in addition produces a differential setting of an actuating-rack which is automatically and positively restored by the pcwer mechanism so as to add the item upon the totalizer. For multiplying, a finger lever is set so as to break the positive connection between the differential members of the keyboard and the actuating- racks and thereupon the machine is no longer immediately operatively responsive to each key manipulation but the whole of the multiplicand is first set up and the operation of the machine then initiated by depression of a single multiplier key, which also determines the number of repetitions of the adding-operation. Keys ; keyboards; differential - mechanism.- Each key-stem is bifurcated, Fig. 18, and slotted at 32 to lock, when depressed, with the interrupted flange 48 of a differential bar 44 (one for each bank) provided with stops 51 at progressively different distances from the corresponding key-stems. The bar is spring-controlled so that, when a key is depressed, it moves forward until stopped by the stem. The bar is normally locked against movement by a catch 63, Fig. 4, engaging a lug 66 on the bar, and raised for release, by portion 72<1> of a swinging yoke 72. This yoke together with a similar one 71 supports a. release bar 69 which tends to occupy a raised position by virtue of a spring 75 connecting the yoke 72 with a. connecting rod 74. The depression of a key however forces the bar 69 downwardly and so releases the catch 63 and permits the differential bar to take up its setting. Each bar is connected by a slotted link 53, Fig. 9, with a lever 57 pivoted at 56 and furnished with a toothed sector 58 engaging a pinion 141 conr.ected by a train of gearing with the numeral wheel of the totalizer 139. Operating by motors.-A source of power is connected with a shaft 91, Fig. 4, which by crank mechanism causes a continuous rocking of a shaft 107. Fixed upon this shaft is a series of double arms 108, 109 provided with pins 112, 127. When a key is depressed and the corresponding actuating lever 57 falls to the prescribed extent, a pivoted dog 116 on the lever comes into the path of oscillation of a spring dog 111 pivoted on the pin 112 of the corresponding rocking arm. The dog 116 is thereupon rocked so that its other end 117 disengages from a notch 121 in a bracket 123 pivoted on the lever 57. The bracket consequently swings anticlockwise until a second notch 122 is engaged by the dog end 117 and an arm 125 of the bracket is brought into position to be engaged by the pin 127 upon the return stroke. The lever 57 is thereupon positively raised to normal position and the item set is thus added upon the totalizer. Multiplying &c. by repetition.-When the finger lever is positioned for multiplication, it releases a spring-controlled shaft 173, Fig. 9, provided with pins to engage and oscillate dogs 178 mounted on levers 179 pivoted at 181. The upper arms of the dogs thereupon engage beneath shoulders 183 on arms of the yokes 72 so that when the release bar 69 referred to above is depressed by a key and this yoke is lowered, the corresponding lever 179 is forced downwardly and a pin 189 carried by it and engaging in the slot 161 in the link 53, causes the latter to descend and so be free of the stop 166 which is carried by the differential bar, and normally occupies a recessed portion of the slot as shown in Fig. 9. The positive connection between the differential bar of the actuating sector is thus broken and the latter is free to be rocked any number of times so as repeatedly to add on the number as set by the key and determined by the position of the stop 166. The links 53 are retained in their lower positions, during multiplying, by latches 187 pivoted at 185 and connected by an universal bar 188. The manner in which the multiplier keys control the number of additions is as follows. A differential bar 191, Fig. 16, similar to the multiplicand bars 44 is set by the multiplier bank and through a link 214 connected with the forward pivotal support of the bar 191, positions a toothed sector 213 pivoted at 56. A lever 202 also pivoted at 56 is connected to a slotted link 203 similar to links 53 and co-operating with a stop 265 carried by the differential bar 191. Under the control of shaft 173 this link is raised or lowered to be free of or engage with the stop 265 by mechanism, including a dog 210, similar to that described above in connection with the links 53 and dogs 178. The sector 213, when in normal position, depresses by means of a pin 242 a hook-shaped arm pivoted on a lever 231, and thus maintains the end of this arm below the path of oscillation of a pin 226 on a double arm 223 rocked by the motor-driven shaft 107 through reducing gearing 219, 222. When the sector 213 has been set however, the arm 228 being thus released is engaged by the pin and driven rearwardly, thus rocking the lever 231 and through a link 237 and the bar 188 releasing all the links 53 hitherto held by the latches 187. The actuating sectors 58 now drop and are then raised by the action of the rocking shaft 107, this operation continuing as many times as desired, according to the value of the multiplier key depressed. The operation is terminated when a pawl 252 mounted upon the lever 202 has worked off the predetermined number of teeth on the sector. This lever 202 is provided with mechanism 247, similar to that described in connection with the operation of the actuating sectors 58 from the shaft 107, so that the lever is rocked at each reciprocation of the shaft and consequently drives the sector 213 upwardly step-by-step. A detent 261 pivoted at 262 prevents return movement of the sector during this action. As the sector makes its penultimate step towards normal position, a projection 266 thereon pushes back the pawl 252 to be subsequently retained by a latch 256. Moreover a dog 289 on the sector bears upon a duplex hooked arm pivoted on a lever coaxial with lever 231, and so brings the arm within the path of movement of a pin on an arm fixed on the shaft 107. Consequently the hooked arm with its lever is pulled forward and through a link rocks the shaft 173 thus releasing the dogs 178, 210 from the arms of the yokes 72 and allowing the links 53, 203 to rise. Hence in the last operation of the actuating sectors, the links in their return movement again engage by their recesses with the stops on the differential bars so that the normal positive connection of the bars with their actuating sectors and the lever 202 again obtains. When the 1 multiplier key is depressed, a more direct action of the parts occurs. The stem of this key rocks a lever 301 connected by a link 305 with a pin on a member 235 pivoted on the lever 231 and provided with a hook-like spring-pressed arm 308 adapted to engage a pin on an arm fixed to shaft 173. When therefore the lever 231 is rocked by the operation of the machine, the shaft 173 is oscillated directly by these connections so as to allow the links to rise and re-engage with the stops on the differential bars.