Patent GB-582052-A (GB)
Abstract: 582,052. Calculating - apparatus. AKTIEBOLAGET FACIT. May 30, 1944, No. 10402. Convention date, May 19, 1943. [Class 106 (i)] In a power-operated calculating-machine with automatic step shifting in multiplication in dependence of the restoring motions of the kind of operation keys (multiplication and division keys or motor keys), the step shifting mechanism is under the control of an impulse member 69 which is under the action of the keys 75, 76 so that the impulse member is disconnected when one of the keys is depressed, but is again engaged and starts the step shifting mechanism when the depressed key is released and returns to its position of rest. The machine is a modification of that described in Specification 551,311. Specifications 351,276, 431,623, 431,627, 574,000 and 575,100 also are referred to. Multiplication. The control levers (not shown) are set as described in Specification 551,311, the multiplicand is entered into the actuator in known manner and the multiplication key 75 (Fig. 1) depressed.' An arm 85 of this key rocks a lever 331 about its fulcrum 333 and closes contacts 334 to start the driving motor. The motor (not shown) drives gears 12a, 12b (Fig. 1) integral with'cam 25, 26 (Fig. 4), the gears driving, directly and through an idler gear 17 (Fig. 1) respectively, two gears 14, 15 rotating freely in opposite directions on a shaft 16. The cams 25, 26 (Fig. 4) oscillate a lever 23 about its pivot 24 (see also Figs. and 2). Depression of the key 75 disengages a projection 79 on the key from the edge 68 of a coupling rod 28 (Fig. 2) which is then pulled upwards by a spring 32 until its upper end is caught by the oscillating lever 23, thus shifting the rod 28 and associated parts-in particular a rectangular cam-plate 36 (Fig. 7)-laterally to the left in Fig. 2, the cam-plate sliding on a shaft 37 against the action of a spring 40. A projection 41 holds the plate 36 in its displaced position by engaging a projection 42 on an arm 44, controlled by a spring-urged member 45. Displacement of the cam-plate 36 moves a pawl 18 (Fig. 1), positioned in the neck of the cam-plate and pivoted to a block secured to the shaft 16, into engagement with a shoulder (not shown) on one or other of the oppositely rotating gears 14, 15 (15 in this case, 14 in the case of division). Thus, the shaft 16, which is geared to the actuator shaft 58, starts to rotate in a positive direction for multiplication, the point of the pawl 18 sliding along one side of a guide rail 22. Displacement of the cam-plate 36i also displaces a pin 48 (Figs. 1 and 6), gripped between shaped rollers 49, 50 on the ends of actuator stop pawls 51, 52, pivoted on a shaft 53, and, against theaction of a spring 501, forces the rollers apart and so lifts the pawls out of engagement with shoulders 54, 55 on buffer discs 56, 57, thus allowing the actuator to be rotated. Secured to the shaft 58 (Fig. 1) is a disc with an eccentric cam slot in which runs a roller 65 journalled on a three-armed member 310 (Fig. 5) pivoted on a pin 67. As the actuator rotates, the member 310 is rocked in a clockwise direction and its arm 66 (Fig. 2) engages the edge 68 of the raised coupling rod 28 and presses it down. A hook 81 (Fig. 1), pivoted to the depressed key member, is pulled by its spring 82 until the point 84 of the hook engages the edge 68 of the coupling rod 28, thus holding the rod down while the key 75 is in its depressed position. As the member 310 rocks about its pivot 67 (Fig. 5), the hook 69, pivoted at its end 70, is spring-urged against a pin 72, and also, since the multiplication key 75 (Fig. 1) is depressed, a bent portion 73 on the hook engages a striking surface 74 on the key. This disengages the hook from the pin 72 so that its toe 69a clears a tongue 89 of a lever 86 (Fig. 5). But when the key 75 is returned to its upper position, the toe 69a engages and rocks the lever 86 anticlockwise, whereby a tongue 92 pushes the lever 45 (Fig. 2) forward and thus disengages the projection 42 from the projection 41 on the cam-plate 36, allowing the latter to be returned to its central position by the spring 40. The point of the pawl 18 (Fig. 1) is then cammed into its central (inoperative) position. This movement of the cam-plate also restores the pin 48 to its central position and so releases the stop pawls 51, 52 to engage the buffer discs 55, 56. These roughly semicircular discs are loose upon the shaft 58 and are pressed into engagement with an adjustable bush 60 by a buffer spring 59. The buffer discs are loosely coupled to a notched disc 107 (Fig., 11) by pins 108, 109 on the disc which project through larger holes 110, 111 in the buffer discs. The disc 107 is fixed to the actuator shaft 58. By this arrangement the kinetic energy of the actuator is absorbed in the buffer spring 59 after the engagement of the stop pawls, and the proper engagement of the pawls is ensured. The rocking of.the lever 86 (Fig. 5) disengages a tongue 90 from the point 93 of a spring-urged arm 271 allowing it to rise. This brings into operation the step-shifting mechanism as described in Specification 551,311. The arm 271 is restored by a pin 273 which, moving to the left, engages a sloping surface on the arm and presses it down to be engaged once again by the tongue 90. The pin 273 also moves in a slot 99 (Fig. 1) of a member 95, pivoted at 96, pressing it down so that a bent portion 97 (see also Fig. 2) engages the ends 98 of the coupling rods 28, 29, thus ensuring that the actuator cannot be started whilst a shifting operation is being carried out. When the key 75 is returned to its upper position, the contact lever 331 is maintained in its operative position by a pin 103 on a link 100 which has tongues 101 overlying the stop pawls 51, 52 and so preventing the opening of the driving motor circuit until the pawls drop into engagement with the shoulders 54, 55. Division. The operation is similar to that for multiplication excepting that the division key 76 raises the coupling rod 29 and the actuator is driven in a negative direction. The setting of the machinefor division (see Specification 551,311) brings a slide 241 into the path of the hook 69 preventing it from acting upon the lever 86. Thus, the actuator continues its negative rotations until the capacity of the results register is exceeded and the carry mechanism, in known manner, rocks a lever 102 (Fig. 5) clockwise. This movement acts upon the lever 86 and initiates the stopping and shifting of the actuator and the continuance of the automatic division in known manner and as described in Specification 551,311. Subtraction. The lever 358a (Fig. 11). is pressed down, the division key is depressed and the machine operates as described in Specification. 551,311. The clearing key 406 (Fig. 11) slides on a pin 400a and is pivotally connected to a coupling arm 392 controlling the driving motor. A projection 400c on the key stem rides on the edge of the disc 107 and prevents depression of the clearing key until a notch 107a comes opposite the projection 400c.