Patent GB-904555-A (GB)
Title: Computing and recording apparatus
IPC: G06C11/08
Filed: 1959-12-22
Abstract: 904,555. Calculating-machines. ADDO A.B. Dec. 22, 1959 [Dec. 24, 1958], No. 43572/59. Class 106 (1). A calculating or other machine with ten digit keys and a starting key by which the machine is caused to perform a cycle of operation has a checking device controlled by the digit keys and arranged when the digit keys depressed fulfil a specified condition, to withdraw a blocking member from the starting key so as to permit a cycle of operation. The invention is applied to a ten-key calculating machine for ensuring the correct setting of an account number including, in its units order, a checking digit. The latter is such that the sum of the units digit and every other higher order digit plus the sum of weighted values of the tens digit and every other higher order digit is equal to, or a multiple of, ten. The weighted values are obtained by doubling the digits and, in the case of digits 5-9, subtracting 9. On depressing a digit key 38, Figs. 1 and 3, a lever 65 is rocked so as to set a corresponding pin 160 in the pin-carriage, move a hook on its end into the path of a corresponding projection 62b of a set of discs 62 and rock a bail 137 to close a switch 136, Fig. 13, to energize a solenoid 52 which rocks a frame 63 carrying the discs 62 to the left. A wheel 71, Fig. 11, fast with the discs is thus moved into contact with a constantly driven sleeve 70 and a pinion 76 into mesh with a pinion 77 on a shaft 80a. The discs 62 and shaft 80a are thus frictionally driven until the appropriate disc 62 engages the set lever 65. The shaft 80a is rotated in this way an amount corresponding to the digit key 38 or to the weighted value of that digit; a weighted value is introduced by energizing a solenoid 53 to shift the discs 62 axially to bring into effective position an interspersed alternative set of discs 62, the projections on which are positioned according to the weighted values. The solenoid 53 is controlled by a switch 89, alternately closed and opened by a toothed bar 87 which moves with the pin-carriage, and by a switch 313 set by a key 313a according to whether the number of digits is odd or even. After a number has been set, the shaft 80a is thus positioned in accordance with the sum of the appropriate actual and weighted values of the digits. If this sum is a multiple of ten, a notch 82 in a disc 80 allows the starting key 39 to be depressed. Moreover, one of two switches 79a, 79b on the shaft 78 lights a pair of lamps 47 at the bottom of a group of lamps, arranged in the same manner as the digit keys, to indicate a correct setting of the number. If a digit of the account number is not known, instead of depressing a digit key when that digit is to be set, keys 311a and 312a are depressed together with the zero key. Switches 311, 312 closed by the keys 311a, 312a then complete a circuit for the digit indicating lamps and, if that order corresponds to a weighted digit value, a relay 314. When the last digit has been set, one of the switches 79a, 79b, depending on whether or not the relay 314 has been energized, lights that one of the lamps 47 corresponding to the unknown digit. The setting mechanism is then cleared and re-set. A slide 41 secured to the pin-carriage is moved to the right to re-set the mechanism. The slide rocks a lever 164, Fig. 5, to close a switch 166 and place a hook 167 in the path of a tooth 168 of a disc 163 on the shaft 78 geared to the shaft 80a, Fig. 11. The switch 166 energizes the solenoid 52 to cause the shaft 78 to be driven until it is arrested in zero position by the engagement of the tooth 168 against the hook 167. On the return of the discs 62 they are driven to zero position as determined by the abutment of a tooth against a fixed stop 69.