Patent GB-413205-A (GB)
IPC: G06C23/06
Abstract: 413,205. Calculating-apparatus. AKTIEBOLAGET FACIT, Atvidaberg, Sweden. Dec. 15, 1933, No. 35410. Convention date, March 30. [Class 106 (i).] In machines for the four rules a reversible motor drive for effecting the rotations of the differential actuator is provided wherein one or other of a pair of toothed wheels driven in opposite directions is adapted to be operatively connected to the shaft of the actuator by the lateral rocking movement of a pawl so as to engage a projection on one or other of the wheels. The pawl is under the control of a + or - start key. The invention is described as applied to a machine with actuators of the cam-disc and pin wheel type supported on a main shaft 5, Fig. 1. The electric motor drive is applied to a shaft 8 that gears with a shaft 9, Figs. 1, and 5 on which is secured a pair of wheels 10, 11 ; the wheel 11 gears directly with a wheel 12 while the wheel 10 drives a wheel 13 through an intermediate pinion 14. The wheels 12, 13 are loose on a shaft 15, Figs. 1, and 6 and thus rotate in opposite directions. To the shaft 15 is secured an arm 16 carrying a pin 18 on which is pivoted a coupling arm or pawl 17 adapted when rocked from its mid position to one or other side to engage a projection 20, or 21 on the corresponding wheel 12 or 13 to couple it to the shaft 15. The rotation of the shaft 15 is transmitted through gearing 22-25 to the actuator shaft 5. The direction of rotation is determined by the depression of one or other of a pair of start keys 1, 2 which rock a triangular member 34 to close the motor circuit contacts 35 and through projections 91, Figs. 1, and 4 on the key stems, raises one or other of the push rods 36, 37 into the path of movement of a spring controlled slide 30 on the end of a pivoted lever 29. This lever is oscillated by a cam cylinder 26 on the shaft 9 so as to displace the rod 36, or 37 that has been elevated to the left or right in Fig. 4. Co-operating with the rods 36, 37, through pins 38, is a cam-slotted guide member 39, Figs. 1, and 8, which follows the displacement of the operated rod against the action of a spring 41. The end of the pawl 17 normally engages the cam-slot so that when the member 39 is moved the pawl is rocked into the path of movement of one or other of the projections 20, 21 of the wheels 12, 13 and causes the shaft 15 to rotate accordingly. The pawl is held in its displaced position by a part circumferential guide rail 50. When the depressed key 1 or 2 is released the corresponding rod is lowered and the member 39 returns to its normal mid position whereupon the pawl is rendered inoperative. The member 39 is locked in either of its set positions by a spring controlled rod 45, or 46 connected to corresponding rods 43, 44 co-operating with the keys 1, 2. The shaft 5 is held in its full cycle position by the engagement of pawls 54, 55 with a projection 53 on a disc 52 secured to the shaft. The pawls 54, 55 are controlled by a common spring 60 and are pivoted on spring controlled arms 57, 58, carried by a fixed pin 56. At the beginning of an operation the pawls are released to free the disc 52 by the co-operation of a lever 61 with pins 62 on the pawls, the lever 61 being rocked by one of the pins 38 engaging the cam shaped end of the lever 61. The disc 52 has a cam recess on its periphery and a lever 19 co-operating with the periphery and with a pin on the triangular plate 34 maintains the contacts 35 closed during the rotation of the shaft 5. The restoration of the set pin wheels or other setting members to normal may be effected by known mechanism. This mechanism may be controlled by a zeroizing key 3, Fig. 1, which on being pushed in rocks an irregular shaped plate 70 so as to release a pawl 68 of a one revolution clutch which, by engagement with the tooth 65 secured to the shaft 64 driven from the motor shaft 9, transmits the rotation to the wheel 66 provided with a flange 67 on which the pawl 68 is pivoted. The motion is transmitted to a shaft 74 carrying a cam 77 adapted to rock a follower arm 79 the shaft of which is operatively connected to the resetting mechanism. The plate 70, by co-operation with a pin on the triangular plate 34, closes the contacts 35 to initiate the motor operation and a cam 73, by engaging a nose on the plate 70, ensures the completion of a revolution of the shaft 74. The control of the resetting mechanism may be effected automatically; this operation is desirable after a cycle of operation when performing addition or subtraction. For this purpose an add and subtract lever or slide 7 is provided ; in the add and subtract position shown in full lines Fig. 1 a pin 82 on the lever engages a projection 83a on a lever 83 pivoted to the zeroizing key 3. The free end of the lever 83 carries a cam surface 83b lying in the path of movement of two pawls 85, 86 pivotally mounted on the disc 52. During the rotation of the disc one of the pawls passes by the cam surface and near the end of such rotation the other pawl rocks the lever 82 which swings about the pin 82 and presses in the key 3 to initiate the resetting operation. The key 3 during its rearward movement co-operates with a slide 90 to free the ends of the rods 36, 37 from the projections 91 of the start keys and by means of a pin 92 rocks the looking rods 45, 46 to free the guide member 39 so that the parts return to normal even if the start key is held depressed. The slide 90 at its rear end has a projection 90a engaging a pin 94 on a lever 95 co-operating with a cam dise on the shaft 74 to prevent premature return of the slide 90. This slide 90 is utilized in division operations to stop the machine operation when the highest numeral wheel of the totalizing-counter passes through the " 9 " position; the transfer lever associated with this numeral wheel rocks an arm 102 and through a lever 104 and pin 105 operates the slide 90. British Specification 351,276, U.S.A. Specification 1,927,771, and German Specification 535,576 are referred to.