Textiles: cloth finishing – Expanding device for textile webs – Spreader
Patent
1994-04-26
1995-10-10
Chapman, Jeanette E.
Textiles: cloth finishing
Expanding device for textile webs
Spreader
26 87, D06C 306
Patent
active
054559928
DESCRIPTION:
BRIEF SUMMARY
THE PRESENT INVENTION relates to a widening device and more particularly a widening device for increasing the width of a moving web of material.
DE-PS 30 067 discloses a widening or width-extending device in which a textile web of material is unwound from a roll, conveyed through the nip between co-operating profiled rollers, and rewound. A width-stretching device can be disposed in front of and behind the nip. The co-operating rollers have their periphery formed with a helical relief extending from the centre of the rollers outwards to both sides and with a constant pitch, but opposite on either side of the centre. This relief meshes with a corresponding relief on the co-operating roller, so that the peaks of the relief on one roller engage in the troughs between the peaks of the relief on the other roller. The two rollers can be adjusted relative to one another in a controlled manner.
For the purposes of the following description, the term "width-extending or extension" means transverse stretching, i.e. a change in the dimensions of the web of material in the width direction, and is associated with considerable stretching forces exerted across the material. In contrast the term "width stretching" is used to describe the operation where a web which is not completely flat is simply spread out and flattened, when only relatively small forces are exerted across the web.
The "width-extending" effect, in the present sense, of the known device is based on the fact that the web, which would normally be flat when running through the nip, is pressed by the peaks on one roller into the troughs the peaks on the other roller. In the process it is held by friction against neighbouring peaks, so that penetration is opposed by a force which results in stretching. The web extends in a zigzag in the nip, and where there is no substantial change in the position of the edges, the result is, of course, a greater extension of the web in the width direction, i.e. the web is transversely stretched. The amount of transverse stretching depends on the extent to which the helical reliefs on the two co-operating rollers engage in one another. If the engagement is deep, the web may quite possibly be torn into longitudinal strips.
The aim of the known device is to equalise the locally attainable width extension across the web. Another width-extending device is a tentering frame having tenterhooks which engage the edges of the web and pull them apart. This however results in an approximately hyperbolic variation in stretch across the width. The stretching at the edge is greatest and there the weft density of the finished product is considerably smaller. These differences in stretching also show up when the web has been treated, e.g. in the colour shade.
In the case of the width-extending device of DE-PS 30 067, stretching occurs at a number of places uniformly distributed across the web between each pair of peaks, which are separated by about 1 to 2 cm. The forces are applied, not at widely distant places but in the immediate neighbourhood of each place under consideration. The conditions are the same at all places, at least within the width of the web. The resulting stretching is correspondingly constant. The places where force is applied are much less stressed than in the tentering frame, because instead of forces being applied at two locations, (at the edge of the web), it is applied at about a hundred positions following one another in line along the width-extending nip.
DE-PS 30 067 dates from the year 1884. In the meantime the effect attainable by the device has been given new importance by the "micro-elongation" (abbreviation ML) process (see Textilbetrieb 95 (1977), pages 58 to 60). The aim is to increase the width of the product without reducing the length, or to retain a given width in order to counteract shrinkage during the various textile wet-treatment processes. The intention is to increase the area of the high-finished final product by a small percentage. The ML process is performed on a device substantially similar to t
REFERENCES:
patent: 634307 (1899-10-01), Neidhardt
patent: 679425 (1901-07-01), Kertesz
patent: 3499185 (1970-03-01), Schmidt et al.
patent: 3652002 (1972-03-01), Dennis
patent: 4087226 (1978-05-01), Mercer
patent: 4116892 (1978-09-01), Schwarz
patent: 4368565 (1983-01-01), Schwarz
Sonderdruck Aus Textilbetrieb, Vogel-Verlag, Wuerzburg, Germany, vol. 95, No. 1/Feb. 1977: Das ML-(Mikrolangungs-) Verfahren.
Kadagies Klaus
Kurschatke Wolfgang
Meyer Christian
Schneider Axel
von Harten Gunter
Chapman Jeanette E.
Eduard Kusters Maschinenfabrik GmbH & Co. KG
Vanatta Amy Brooke
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