Patent GB-497588-A (GB)
Title: Improvements in or relating to calculating machines
Filed: 1937-06-19
Abstract: 497,588. Calculating - apparatus ; statistical machines. BALDWIN, R. E. June 19, 1937, No. 17091. [Class 106 (i)] Statistical apparatus; adding and subtracting apparatus. - A calculating machine comprises means for entering an amount into an accumulator and means for reducing the amount by the algebraic sum of a series of other amounts, each time the algebraic sum becomes negative with respect to the sign of the amount in the accumulator. The invention is shown as applied to a record card controlled tabulating machine of the kind having an algebraic accumulator and control mechanism therefor as described in Specification 405,666, and includes means for entering positive and negative amounts read from the record into the algebraic accumulator, means for entering the amount read from the first of a group of records into another accumulator and for suppressing the entry of this amount into the algebraic accumulator, means for determining at each machine cycle the sign of the balance in the algebraic accumulator, means operative under the control of the sign-determining means to transfer the balance in the algebraic accumulator to the other accumulator and to zeroize the algebraic accumulator each time the balance becomes negative, and means for causing the other accumulator to print the amount it holds when a change in group designation occurs. Specification 271,935, [Class 106 (i)], also is referred to. Positive and negative amounts are sensed, set up in sectors, and entered into the rear algebraic accumulator in known manner. The present machine is modified to cause an amount representing a balance read from the first card of a group to be entered into the front accumulator 151. A card punched only to actuate the wire 183, Fig. 2, is inserted between each group and causes a bell-crank 181 to be rotated. An arm 301 on the same shaft lowers a reciprocating pawl 302 into engagement with one of two symmetricallyplaced low teeth 306 on a twelve-toothed ratchet 303 thereby causing the latter to be stepped round until the next low tooth is reached. A bell-crank 307, Fig. 4, is influenced by a cam 300 turning with the ratchet 303, whereby its upper arm 308 is moved anticlockwise to prevent the return of an arm 309, Fig. 2, moved to an upper position (shown dotted) by rotation of the back total shaft 141 whereby the algebraic accumulator is held out of engagement with the sectors in a known manner. Moreover, the arm 308, through a link 310, rotates a lever 311 about its pivot 178, and a block 311a engages a pin 172a to rotate a known bell-crank 171 and cause the amount set up in the sectors to be added to the front accumulator. A member N, Fig. 2, is displaced as in the known machine when the sign of the total in the algebraic accumulator becomes negative. The position of the member N is sensed at each cycle by a spring-urged arm 313 linked by a member 317, Figs. 2 and 7, to an arm 318 pivoted at 319 and actuated by a cam 314. The arm 313 is obstructed by the member N when the latter is in the positive position as shown, but when a change of sign occurs the member 313 is given free movement and lifts the link 317 to cause an obstructor 312, linked to the arm 318, to move into the path of a pin 322 on the total testing lever T thereby initiating an operation transferring the total in the rear accumulator to the front accumulator. To prevent this operation from interfering with the sensing of the following card, an additional card, blank except for the designation punching, is inserted after each record card. At the end of a group of cards, change of designation in the known machine initiates an operation tending to transfer the total in the rear algebraic accumulator to the front accumulator. According to the invention this operation is necessary only when the amount is negative. To this end, a pin 327, Fig. 3, on a member 326, Figs. 3 and 7, which is periodically moved by a T-shaped member 328-329-335 pivoted at 319 and influenced by a cam 330, engages a short lever 324 and moves the member 153 into a neutral position to prevent the engagement of the front accumulator with the sectors. If, however, a negative amount is to be transferred, a pin 312a on the obstructor 312 prevents movement of the arm 335 of the T-shaped member whereby the link 326 is not moved, the total is entered into the front accumulator and total-taking and printing proceeds in the normal manner. Since the wheels of the algebraic accumulator will be left at negative zero after total-taking, the member N will be in a position to initiate further total-taking. To prevent this, a slotted link 341, Fig. 2, is arranged, upon rotation of the back total shaft 141, to pull a latch 343 over a pin 345 on the link 317. Specifications 371,849 and 426,054 are referred to in the Provisional Specification.