| 摘要 |
<p>1280659 Feeding webs SCHWEIZERISCHE INDUSTRIE GES 3 Dec 1969 [3 Dec 1968] 58926/69 Heading B8R [Also in Divisions B4 and F2] In apparatus for cyclically performing work operations, e.g. cutting and welding, or moving elongate material such as paper, tubing or cables, feeding and processing assemblies are provided, each assembly having a pair of parallel shafts associated with inter-related drive members and couplings so arranged that the shafts of one assembly are rotated at a uniform rate whilst the shafts of the other assembly are rotated alternately at a higher and a lower rate during each cycle of operation. As shown, a paper web 2 from a supply roll mounted on a shaft 1 is fed to a cutting device 13 by means of rollers 4 mounted on two vertically spaced shafts 5 and 6 which are coupled together at one pair of adjacent ends by similar intermeshing gear-wheels 7; at their other ends the shafts 5, 6 are coupled together by way of respective electromagnetic couplings 8, 9 and two intermeshing gear-wheels 10, 11, the gear-wheel 10 having more teeth than the gear-wheel 11. The gear-wheel 10 meshes with a driven gear-wheel 12 which also drives the cutting device 13 constituted by coupled shafts 14, 15 carrying cooperating knife blades 17, 18. Thus, when coupling 9 only is energized the shaft 5 is driven by the gear-wheels 12, 10, 11, the closed coupling 9, the shaft 6 and the gear-wheels 7 at a number of revolutions corresponding to a feeding speed V 1 of the web 2; when coupling 8 only is energized the shaft 5 is driven by gear-wheels 12, 10, and the closed coupling 8, and drives the shaft 6 through the gear-wheels 7 at a speed of rotation corresponding to a feeding speed V 2 of the web 2, V 2 being smaller than V 1 . A control circuit (Fig. 2, not shown), including a cam operated switch 22 asosciated with the cutting device 13 and a photo-electric scanning head 24 responsive to marks 23 on the web 2, controls the energization of the couplings 8, 9 so that the web is advanced alternately at a higher rate and a lower rate during each operating cycle of the cutting device. The Specification explains, with reference to Figs. 3 and 4 (not shown) how this arrangement results in the cutting of the web at predetermined points into pieces having a length equal to the distance a between the marks 23. In a modification (Figs. 5 to 7, not shown) the scanning head 24 is omitted the shafts 5 and 6 are driven at a constant speed and the couplings 8, 9 are associated with the cutting device 13 the shafts of which rotate alternately at a higher rate and a lower rate during each operating cycle as the couplings are selectively energized by a circuit including a cam-controlled switch associated with the shaft 5.</p> |
