Patent GB-704764-A (GB)
Title: Improvements in or relating to type-wheel printing mechanisms
Inventor: KEEN HAROLD HALL
Filed: 1950-09-07
Abstract: 704,764. Statistical apparatus. BRITISH TABULATING MACHINE CO., Ltd. Aug. 1, 1951 [Sept. 7, 1950], No. 22084/50. Class 106 (1). [Also in Groups XVI and XXIV] In a record card controlled statistical machine the type wheels are each driven by their own clutch to effect both character selection and resetting, the clutches are engaged under the control of one or more electrical impulses timed according to a character representing code, and the clutches are disengaged at one or more predetermined times, the last disengagement so effected bringing each type wheel into selected position at the printing line ; after printing each clutch is re-engaged and finally disengaged when the type wheels reach a reset position. The type wheels 22, are each arranged at column spaces on their own plate 14 swingable about a shaft 15 to effect impression; alternate wheels 22 being rotated a selective amount by gearing 9, 8, 10; 16, 75, 23, 57 and a clutch mechanism from a shaft 3, and gearing 9, 8, 7, 6, and a clutch mechanism from a shaft 2. The clutch mechanisms (see Fig. 3) comprise a driving ratchet 69 engaged by a pawl 61 pivotally attached through the spokes of a ratchet wheel 55 to a plate 59 allowing a limited relative movement between the wheel 55 and the plate 59. The plate 59 has secured to it the gears 57 (or 6) for rotating the type wheels, the amount of rotation being controlled by a clutch lever 24, Fig. 1, operated by stop and start magnets 25, 26, mounted on plates secured to cross bars 38, 34. There is one pair of stop and start magnets for each type wheel and to effect this they are staggered into four positions supported by additional cross bars 37 ; 35, 33; and 33, 36. When a start magnet 25 is energized armature 45 rocks anti-clockwise pivoting the clutch lever 24 away from a ratchet wheel 55 whereupon it begins to rotate by the pressure of a spring 71 connected to the pawl 61 which then slides down a cam surface 66 and the projection 64 is engaged by a notch in the driving ratchet 69 and the plate 59 and gear 57 are driven until the stop magnet is energized. Ratchet wheel 55 is thereupon arrested but plate 59 continues to revolve due to inertia and the pawl 61 is cammed out of engagement with the ratchet 69 by the surface 66. The clutch lever is held in either position by, a spring detent lever 51, since the operating pulse from a card sensing mechanism or a read-out counter mechanism of a calculating machine is of short duration only. A single pulse is used for digits and a digits impulse plus a second impulse for letters. The digits are arranged four characters apart on the type wheels and in-between each is arranged three letters so that for the selection of a letter a second amount of rotation of the clutch magnet is required. The time available for resetting the type wheels is much less in some cases than the setting time but by means of a differential gear and a Geneva mechanism, Figs. 5, 6 (not shown), the rotation of the type wheels during resetting is speeded up. Hammer impression arrangements. The plates 14, Fig. 1, carrying the type wheels are rocked after the setting of the type wheels by a nose 77 of the plate which drops into a notch 78 on a cyclicly driven shaft 17. Those plates carrying a type wheel which has not been selected are held back by the inwardly placed side edge of a slot 93 engaging a projection 92 on a lever 91 engaging with a cam 89 attached to the gear 76 having a notch in the reset or normal position. When any wheel is selected for printing the lever 91 is rocked moving the projection 92 into the wider part of the slot 93 so swinging of the plate 14 may occur. The swinging of the plates 14 may be locked against operation by hammerlock levers 139 individually settable to move a stop arm 141 into the path of notch 146. The levers 139 are mounted on a rockable assembly 137-138 moved when it is selectively required to release the plates 14. Assembly 137-138 is swung by a link 134, Fig. 4A, a plate 108, link 109, a toggle 109, 110 and a cam 123. Normally the cyclic rotation of the cam has no effect on moving the plate 108 as the end 115 of the toggle is free but if a magnet 122 is energized in combination with the action of a cam 124 engaging the upper tip of a lever 118 a notch 127 moves behind a lever 111 so that when the cam 123 next engages the toggle joint 114 the end 115 is fixed and movement is transmitted to the plate 108. The stop arms 141 may be moved by a lever 144 into engagement with the notches 146 irrespective of the position of the assembly 137-139. Automatic printing of zeroes. Each type wheel in addition to having a zero in its coded position has also a zero at the reset or normal position so that if required it may be printed even if no code impulse is received in that column. The levers 91 which move when a type wheel has moved off normal position are formed with extensions 91a with a side flange 103 at the top in one direction and a side flange 104 at the bottom in the other direction so that when a manually settable slide 96 is in the innermost position as shown in Fig. 1 an interposer 105 lies between the upper flange of one lever 91 and the lower flange of the next; thus movement of one lever 91 is transmitted to the next. The interposer in the other extreme position is quite free of the flanges 103, 104, so no automatic zero printing takes place. In the intermediate position the interposer is selectively made operative by rocking of a slide comb 97 mounted on levers 99 on a shaft 100 actuated by a linkage 107, plate 108 linkage 109, 110 and cam 123, Fig. 4A. When it is required to print a zero in a next but one column as is required when printing monetary values a V-shaped link 129 bridges an intermediate interposer 105 and makes slidable engagement with the two required levers 91. Aligning for impression. The type wheels are aligned for impression by a detent 87 operated by the scissors action of the parts 80-86 as the end 82 leaves the adjustable fixed stop 84. Operation.-Impulses from the card sensing a counter mechanism are plugged into the socket 198, Fig. 8, representing the circuit arrangements for one column and the first impulse representing the digits operates the start magnet 26 and the type wheel is rotated until 171 degrees when cam operated contacts 194 operate the stop magnet. If a letter is to be printed an additional impulse again operates the start magnet and is stopped by cam contacts 195, 196, 197 corresponding to codes O, X, Y. Printing occurs at 225 degrees, and at 234 degrees cam contacts 192 operate the start magnet 26 to effect resetting through contacts 184 and shifted contacts 190. The wheels are stopped at the reset position by operation of the stop magnet 25 through shifted contacts 191 (closed between 240 degrees- 360 degrees) and contacts 183, Fig. 1, which close when a slide 181 is moved to the extreme right by a lever 177 when it engages the high spot of a cam 176, attached to the gear wheel 75 or equivalent, just before reset position. At reset position the slide moves to the left and contacts 183, 184 are opened. Specification 605,132 is referred to.