Patent GB-255487-A (GB)
Title: Improvements in or relating to record-card-controlled statistical machines
Filed: 1926-07-17
Abstract: 255,487. British Tabulating Machine Co., Ltd., (Assignees of Lake, C. D.). July 18, 1925, [Convention date]. Statistical machines. - A statistical machine is provided with a duplex counter adapted to receive both positive and negative items and to display the balance irrespective of sign. The counter comprises two sets of numeral wheels 20, 120 loose on their shafts and geared each to each by spur wheels 36, 136, so that they turn in opposite directions. The lower set of wheels is driven directly when the amount entered is positive, the drive being effected from a driven shaft 33 through the intermediary of clutches controlled by levers 26 tripped by the armatures of magnets 21 in circuit with the card brushes. Negative amounts are distinguished on the cards by a particular perforation which permits the energization of the circuit of a magnet 94. The armature 95 of this magnet is thus raised to register with a notch 96 in a spring-controlled bail 97 pivoted at 98 with the result that the bail is swung counterclockwise to break contacts 91 and close contacts 101. An upper set of clutch-controlling magnets 121 is consequently thrown into circuit and effects through clutch levers 126 the entry of the negative amount into the upper set of numeral wheels, the lower set of wheels therefore being rotated to similar extents but in the reverse direction. An interlock is provided to ensure that the sets of counteroperating clutches cannot be simultaneously in action and for this purpose a notched plate 270 is controlled in position by the bail 97 so that, when for example, the lower clutches are in operation, the movement of the clutch-restoring plate 42 is not interfered with, but otherwise, with the upper clutches functioning, the plate 42 is held to the left and the lower clutches maintained disengaged. Similar control of the upper clutches is exercised through the restoring plate 142. A bail 281 is controlled by the counter-resetting cam 286 so as to hold the resetting clutches out of engagement with the resetting shaft, except when the cam is out of normal position. The lower numeral wheels are each furnished with lateral pins 287 engaged lightly by detent fingers of a bail 289 except during zeroizing when the displacement of recess 291 by the rotation of cam 286 removes the fingers to permit free movement of the numeral wheel. The bail 289 also has connection at 292 with a lever 293 controlled by a cam 296 timed so that during the clutch-restoring operations of plates 42, 142 the fingers are pressed more firmly against the pins to ensure alignment of the numeral wheels. The result of a tabulation is read from the lower wheels 20 when positive and from the upper wheels when negative. To control the windows accordingly upper and lower orificed shutters 220, 221, Fig. 5. are slidably arranged behind the windows and are connected by a lever 224 so as to move oppositely. When the highest wheel of the upper set of numeral wheels passes from 9 to 0 a cam 233 upon it displaces a latch 235 to free a lever 228 pivoted at 229, this lever under the action of a spring 231 thereupon through a. connection at 227, swinging the shutters to the position shown in Fig. 5 so that the lower numerals only are exposed. When the upper highest wheel, due to the return of the lower set of wheels to the positive condition, passes back from 0 to 9, the cam 233 rocks the lever 228 back to reverse the position of the shutters the lever being then again held by the latch. Inasmuch as the numerals on the upper wheels are the true complement (that is to base 10) of those on the lower wheels a negative result read at the upper windows will only be correct up to and including the first significant digit. To rectify this, therefore, the upper wheels bear two series of numerals side by side, each numeral on the right being one less than its neighbouring digit, and a number of auxiliary shutters 252 are provided in order to expose only those digits that should be read. These shutters, pivoted at 251, have orifices to expose one or other digit and are spring-controlled so as to tend to swing to the right, bearing against one another by projections 256. At the lower end each shutter has a nose 258 engaging a rim or a recess on the left of the numeral wheel to the right, the result being that when any wheel passes from 0 it presses the shutter bearing against it to the left and consequently all higher shutters also so that they expose the right hand digits instead of the left ones to exhibit the corrected amount. Transfer mechanism. - Transfer is effected, after the adding operation, by the engagement, through the counter-operating magnets, of the actuating clutches to effect additional rotation of the higher wheel or wheels. The means employed are similar to those described in Specification 168,311 with the addition, as illustrated in Figs. 2 and 8, of a second set of contacts and their controlling means to provide for transfer when the upper counting-wheels are in operation. This second set of contacts is controlled by cam 202 on the numeral wheel and by bail 158 rocked by the lower and corresponding bail 58.