Patent GB-739747-A (GB)
Abstract: 739,747. Calculating-apparatus. NATIONAL CASH REGISTER CO. Dec. 30, 1953 [Jan. 26, 1953], No. 36243/53. Class 106 (1). The calculating machine described in Specification 648,389 in which as a result of an operation producing a negative balance or overdraft in the balance totalizer, the total-taking keys are rendered ineffective and totals can be taken only by depressing a total key in conjunction with an overdraft key, but in which further postings of checks and deposits can be performed without depressing the overdraft key, is so modified that in addition to the total taking keys the Check and Deposit keys are also rendered ineffective so that every time an overdraft stands on the totalizer the overdraft key has to be depressed before any further postings can be effected and before totals can be taken. In the present machine, the occurrence of an overdraft in the totalizer primes a locking mechanism which is fired by either (a) depressing any total-taking key or (b) depressing either the Check or Deposit key. In the event of (a), the locking mechanism is released by depressing the Overdraft key and the machine will proceed with the operation associated with the particular total taking key depressed, and in the event of (b) the amount key release knob has to be operated to release the detent holding down the particular key depressed, which operation also reprimes the locking mechanism so that the machine is restored to its former potentially looked state, and to effect a further posting the Overdraft key has to be depressed simultaneously with either the Check or Deposit key. As described in Specification 648,389, upon a " Check " posting resulting in an overdraft, a hook-shaped piece 466, Fig. 9, on a shaft 412 rocks clockwise and releases a pin 471 on a lever 472 on which is a second pin 474 engaging a bifurcated lever 475. The raising of arm 466 constitutes priming the locking mechanism and but for a latching device, in the form of a square stud 481, Fig. 8, on a lever 480 integral with the lever 472, the stud engaging a latching lever 483, the lever 472 would be free to be rocked about a shaft 390 by a spring 473 to rock lever 475 and cause a surface 477 on the lever 475 to block the machine release shaft 30. The latching lever 483 is rocked to release or fire the primed locking mechanism by either (a) depressing any total-taking key 163, 164, 165 or 168, Fig. 8, which causes bar 102 to move to the left and rock a lever 111 free on a shaft 77 and to disengage the lever 483 from the stud 481 or (b) depressing either the Check or Deposit key 157 or 159, Fig. 5, which causes a bar 511 carrying a stud 517 to disengage lever 483 from the stud 481. The depression of a total key, Fig. 8, also causes a link 114 attached to a lever 115 free on a shaft 30 to actuate a plunger 119 of a switch 118 which operates a solenoid to rock the machine release shaft 30, which, in turn, starts the machine driving motor, but the clearance between the link 114 and the switch plunger 119 is so adjusted that the stud 481 is released before the switch is operated, and thus the shaft 30 is blocked before the switch is operated and is unable to start the machine. In the event (a), depression of the Overdraft key 158, Fig. 7, cams a bar 421 to the left which, via a stud 420 and a lever 418, moves a stud 417 to push the lever 475, Fig. 9, anticlockwise and free the machine release shaft 30 which can then start the machine. If the Overdraft key is depressed before the total-taking key the stud 417 prevents the lever 475 blocking the machine release shaft 30. In the event (b), the amount key release knob 521, Fig. 14, has to be operated to release the depressed check or deposit key which operation also rocks a lever 527 fixed to the shaft 30 anti-clockwise and thus causes a second lever 492, Fig. 10, also fixed to the shaft 30, to rock anti-clockwise and, by means of a pitman 493 and the lever 472 integral with the lever 480, restore the stud 481 to its latched position and the lever 475 to its normal position where it does not block rocking of the machine release shaft 30. The locking mechanism is thus again primed and to effect a further posting either the Check or Deposit key has to be depressed simultaneously with the Overdraft key.