Patent GB-446104-A (GB)
Title: Improvements in or relating to record-card-controlled printing mechanism
Filed: 1934-10-23
Abstract: 446,104. Typewriters &c. BRITISH TABULATING MACHINE CO., Ltd., Vernon Place, Southampton Row, London, and KEEN, H. H., 25, Sollershott East, Letchworth, Hertfordshire. Oct. 23, 1934, No. 30406. [Class 100 (iv)] Relay type-wheel actions.-In record-card controlled printing-mechanism of the kind comprising two reciprocating controlling-members which are differentially arrested in positions determined by holes in the main and subordinate parts of a column, and jointly determine the position of a setting-member for a type-carrier, the setting-member is connected to the typecarrier by movement-multiplying gearing, the arrangement enabling the strokes of the members, and consequently the dimensions of the mechanism, to be reduced. In the mechanism shown in the Figure, each type-wheel 66 of a set is provided with alphabetical and numeral types and is associated with primary and secondary controlling-racks 23, 41 co-operating with stop-pawls 30, 49 controlled by magnets RPM, FPM which are energized when one of the holes 0 .. 9 and one of the holes X, Y in the record-card are read respectively. A pinion 65 on the type-wheel gears with a setting-rack 53 pivoted at 54 to a differential lever 55 which is pivoted to the rack 23 and has pin-and-slot connection 56, 57 to a bell-crank 58, 62 which has pin-and-slot connection 60, 61 to the rack 41. The racks 23, 41 are mounted on cross-heads 20, 38, a cam 33, 34 for operating the cross-head 38 being so arranged that the cross-head is stationary until the latter part of the stroke of the cross-head 20. The pawl 30 and a stop 52 determine eleven positions of the rack 23, and the pawl 49 and a stop 51 determine three positions of the rack 41. When the rack 23 rises, the rack 53 rotates the type-wheel forwardly, a one-tooth movement of the rack causing three types to pass the printing line. When the rack 41 advances, the rack 53 rotates the type-wheel backwardly and causes one, two, or three types to pass the printing line. To maintain, during movement of the lever 55, uniform transmission ratios between the racks 23, 41 and the rack 53, the slot 57 is inclined with respect to the normal to the rack 53, and is non-radial to the pivot 59 of the bell-crank 58, 62, the arrangement causing the pin 56 to ride up and down the slot 57 during movement of the racks. The bell-crank arms 58, 62 are relatively adjustable. The set of type-wheels revolve on separate bushings 67 mounted with lateral freedom on a common spindle 68. A rocking frame 70 carrying the spindle is mounted on a shaft 71 and is held in contact with adjustable stops 73 by springs 74. Spring- plungers 75 on the frame 70 hold the racks 53 in engagement with the pinions 65. When the type-wheels have been set, the frame 70 is rocked by means of cams 77 on discs 78, and the type-wheels are yieldingly advanced to print on a strip passing over a platen 32, the free mounting of the bushings 67 enabling the spindle to advance slightly after arrest of the type-wheels. Aligning-means, described below, co-operate with the type-wheels. The types on each type-wheel include a full stop which is printed when there are no holes in the associated columns of the record-card. The shaft 103 of the discs 78 is provided with a one revolution clutch controlled by a magnet which is energized only during cycles in which the type-wheels are required to print. The record-cards are read by upper and lower brushes associated with relays and contacts for establishing the circuits of the magnets RPM, FPM. A set of type-bars for printing numerals only may be controlled directly by the racks 23. Aligning for impression.-Aligning-pawls 82, co-operating with teeth 80 on the type-wheels, are pivoted in a frame 84 and are held in contact with a cross-bar 86 of the frame by means of springs 86. The frame 84 is pivoted in the rocking frame 70, a spring 90 normally holding a lug 91 on the frame 84 in contact with an adjustable stop 92. Immediately before the frame 70 is rocked by the cams 77, a pin 94 on a disc 194 rocks the frame 84, and the teeth 93 of the pawls are permitted to enter partly into the spaces 81 between the teeth 80. When the frame 70 is rocked, the racks 53 rise slightly and the type-wheels make a slight clockwise movement, thereby permitting the teeth 93 to enter fully into the tooth-spaces 81. The teeth 80 are formed with inclined and radial faces, and the teeth 93 are similarly shaped.