Patent GB-935846-A (GB)
Title: Improvements in or relating to web feeding apparatus
Inventor: DAVIS ROGER ARTHUR
Filed: 1960-09-13
Abstract: 935,846. Typewriters. INTERNATIONAL COMPUTERS & TABULATORS Ltd. Aug. 22, 1961 [Sept. 13, 1960], No. 31488/60. Class 100 (4). In apparatus in which a laterally-perforated web 1 is passed through a printing head 25 by first and second feed means 4, 26 disposed respectively before and after the head and intermittently driven, the means 4 is of the pin wheel type, the means 4, 26 are positively driven from a power source when a clutch is engaged in response to a feed signal, and the means 26 are also driven at all times through a friction coupling from the power source to maintain the web under tension. The web may be of the multi-ply type, separate feed means and printing heads being provided for each ply. Feed means 4 (Fig. 3). Each of a pair of pin wheels 5 is mounted in a cage 11 which is adjustable along a bar 13 (Fig. 1), to vary the spacing between the wheels. The wheels may have integral pins or pins may be carried on a band trained round a wheel or the driven wheel of a plurality. The wheels 5 are mounted slidably but non-rotatably on a splined tube 6 driven by belt 23 from the driven member 78 of the clutch. Web supports 57 are located between the wheels 5. Feed means 26 (Figs. 1 and 4). A belt 35 drives intermittently from driven member 78 of the main clutch a pair of tubes 26 through oneclutch 34 and gearing 27. The main motor 63 continuously tends to drive these tubes through a belt 42, friction clutch 39 and gear 36. The web 1 passes through the nip between lower tube 26 and friction discs 43 driven by engagement with upper tube 26 so that it is intermittently advanced by belt 35 and continuously tensioned by belt 42. Discs 43 are pivotally mounted in supports 47 slidably mounted on bars 48 so that the spacing of the discs can be altered. By depressing pin 51 the disc is pivoted in its support and swung up from the path of the web to facilitate threading. Main clutch (Figs. 1 and 6). Motor 63 through belt 67 continuously drives a driving member 68 of the clutch. A ratchet wheel 73 has eight rollers 74 located in the annular space between a peripheral flange 73 on the inner face of driving member 68 and an octagonal projection 71 on the corresponding face of driven member 78. The wheel is urged by a spring so as to jam each roller 74 between the flange 73 and a face of projection 71 to engage the clutch but is normally held in non-engaging position by detents 102 intercepting the teeth 91 of the ratchet wheel. These detents are moved into and out of engagement by selectively energizable electromagnets 99, holding permanent magnets being also provided. Driven member 78 is coupled to a fixed projection 88 by a oneway spring clutch 90 which stops member 78 as soon as the main clutch is disengaged. Variable line spacing (Figs. 1 and 6). Each space between adjacent teeth on the ratchet wheel 73 corresponds to half an inch of web feed. By disposing successive detents 102 in alignment with a tooth, a third of the way between teeth, and two-thirds of the way between teeth, the second may be interposed and the first retracted to give a one line feed of a sixth of an inch or the third may be interposed and the first retracted to give a two-line feed of a third of an inch. Similarly, interposition and retraction of two similarly-located detents will allow a three-line feed of half an inch. Suitable location of the detents can provide an eighth of an inch line spacing with a choice of one, two, three or four steps at each operation. Stationary contacts 87 are wiped by contacts 83 on the driven member 78 of the main clutch and actuate a programme device after which feed step to operate the magnets 99 so that they set the detents in the desired position for the next feed step. Alternatively, these contacts send a read-out signal after each step to a programme store controlling the magnets. The read-out signals may alternatively be derived from a photo-electric detector co-operating with a notched wheel rotating with the pin wheels 5 feeding the web.