Patent GB-1186006-A (GB)
Title: Improvements in Power-Operated Printing Calculators
IPC: G06C15/08
Filed: 1967-04-12
Abstract: 1,186,006. Programme control devices. FACIT A.B. 12 April, 1967 [21 April, 1966], No. 16730/67. Heading G4B. A power-operated printing calculator is provided with a plurality of programme bars having stepped profiles, whereby a selected programme bar may be moved into an operative position upon operation of a corresponding function key, to control the various units of the calculator. When the operations controlled in one position of the programme bar are accomplished, the programme bar is stepped into a second operative position and so on, until it reaches its inoperative position. The programme bars 1 have stepped profiles along their upper and lower edges and are slidably mounted on cross-bars 24, 25. Spring- loaded arms 33 engage the rear ends of the programme bars to urge them against stops 30, 31. Operation of a function key moves a stop 30 or 31 whereby the corresponding programme bar is released. Movement of a programme bar is arrested by a stop bail 2. The latter is pivotally mounted on a support 3 and normally held in an upper position by a spring. A setting bail 4 engaging the stop bail through a pin- and-slot connection 4a, is moved by linkage, on depression of a function key, to adjust the vertical position of the stop bail. The abutment surfaces 1a, 16 of the programme bars are staggered so that different positions of the stop bail arrest the programme bars in different operative positions. The stop bail moves about 2 millimetres before the motion of a programme bar is arrested. This movement of the stop bail is transmitted by a system of levers to close a switch completing the circuit of an electric drive motor and to couple two cam assemblies to the motor drive shaft. A number may be entered into the calculating mechanism from a pin carriage or from a further mechanism in which a constant value is set, on depression of one and the same function key. To distinguish automatically between the two operations, the pin carriage actuates an arm 21 when a number is entered therein to displace the stop bail rearwardly through a lever 5. Pivoted U-shaped sensing members are provided along the top and bottom edges of the programme bars. A spring- loaded plate 34 is moved rearwardly under the control of cam-operated lever 208 to move the sensing members into engagement with the programme bars. A cam-operated member 39 engages the programme bars to prevent a second programme bar being operated. Transverse rods 108b secured to the sensing members control the various units of the calculating machine through series of links, levers and cams described in detail in the Specification. Functions controlled by sensing members.- Sensing member 101 is movable into three positions to control function key release, function key release and pin carriage sensing and clearing, or pin carriage sensing. Sensing member 102 controls the multiplier mechanism and product register. Sensing member 103 arrests the cam assemblies during calculating and controls operation of the calculating mechanism. Sensing members 104, 105 control two columns of symbol printing. The quotient register is controlled by sensing member 106. The complement of a negative result is stored in the product register and " reversed " before printing under the control of sensing members 107, 109. The type of calculation is set by sensing member 108. Sensing member 110 controls the ink ribbon shift whereby negative amounts are printed in red. Sensing member 111 controls a cipher wheel 265 described below. Sensing member 112 is movable into three positions to feed the paper two steps, two steps and print, or one step and print. Sensing members 113, 114 and 116 are concerned with preventing errors such as the capacity of the calculator being exceeded. In the event of an error occurring or a multiplication being set up which will exceed the capacity of the calculator, the selected programme is interrupted. A correction key must be operated to bring in a special correction programme. The programme bar is returned stepwise to its initial position under the control of sensing member 115 actuating a member 41 co-operating with teeth along the upper edge of the programme bar. Errors preventing and correcting.-Numbers entered into the calculator are set up on racks 248 forming part of the printing mechanism. In their initial positions, the racks prevent movement of sensing levers 249 through co-operating noses 248a, 249a. On entering a number, the corresponding sensing levers are freed and pivot counterclockwise when a check . bar 250 is rotated clockwise. Projections 249b on the sensing levers strike the surface 252a of a stepped cylinder 252. Thus the leftmost sensing lever will prevent the cylinder 252 rotating an amount corresponding to the number of digits in a set-up numeral. A rotating cam 255 causes the cylinder 252 to rotate clockwise one full revolution. The cylinder is returned towards its initial position by spring means until arrested by the leftmost sensing lever. A cipher wheel 265 is moved to engage a toothed wheel 266 by the sensing member 111. The check bar 250 is rotated counterclockwise to free cylinder 252 which completes its return movement driving the toothed wheel 266 through coupling 262. The number of digits is now entered in the cipher wheel. The cipher wheel moves clear of toothed wheel 266 and into engagement with toothed wheel 287. An apertured plate 293 is moved adjacent sensing fingers 314, 315, 316 under the control of sensing member 113. The sensing fingers move to engage the plate 293 and on penetrating an aperture 293a continue moving until one or more of the sensing fingers engage the cipher wheel through their upper edge. The position of the lower edges 314a of the sensing fingers are sensed by a member 299 which lifts sensing member 116 out of engagement with a programme bar when the capacity of the calculator has been or will be exceeded by the calculation in progress. The sensing member 116 acts through linkage to latch camoperated lever 208 so that the remaining sensing members are prevented from engaging the programme bar. For division, the dividend is shifted to the extreme left-hand end of the register. The cipher wheel engages the toothed wheel 266 before the stepped cylinder starts its counterclockwise rotation and disengaged when the stepped cylinder comes to rest against a sensing lever 249. In this case, the number of digits stored in the cipher wheel indicates the number of places the dividend must be shifted to the left. This action is carried out under the control of sensing lever 114.