Tenter unit

Details Tenter unit Tenter unit

1997-11-25

1998-10-13

Vanatta, Amy B.

Textiles: cloth finishing

Expanding device for textile webs

Spreader

26 91, 26 96, D06C 306

Patent

active

058193820

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

The invention relates to a device for stretching the width of a web of material and more particularly to a width stretching unit having axially spaced needle discs, each of which rotates about an axis that pivots to provide a zone of reduced width between the needle discs and a zone of increased width between the needle discs.


BACKGROUND OF THE INVENTION

The term "needle discs" denotes discs similar to wheels which rotate with the web of material, usually consisting of metal, with their peripheral edges being provided all round with closely set needles of identical lengths. The needle points extend radially outward and penetrate the edges of the web of material to tension the same or keep it tensioned in the direction of the width.
A width stretching unit of this type is known from DE-PS 480 155. A web of material runs onto two obliquely disposed needle discs in the zone where the needle discs have a reduced axial distance between them at their needle edge. The web passes around the needle discs through approximately 240.degree., the edges of the needle discs moving axially apart so that the web of material engaged by the needles at the selvedges is stretched width-wise. The web leaves the needle discs in a plane offset by an angle of about 90.degree. to the entry plane. The needle discs are adjustable in respect of their angular position and transverse distance and are driven jointly.
DE 41 41 779 Al discloses an apparatus for levelling a web of material, such apparatus also operating with two needle discs, the angular position of which is variable. The purpose of this apparatus is to level a web of material with much less expense than a conventional tentering frame and yet achieve a treatment equivalent to the levelling of a tentering frame.
A common feature of the known devices having relatively pivotable needle discs disposed on a common axis is that the treated web of material is released after it leaves the needle discs. If such apparatus is used in mercerizing and similar plants, the web of material tends to shrink again after width stretching. After leaving the needle discs it immediately contracts in the transverse direction.


OBJECTS AND SUMMARY OF THE INVENTION

An object of the invention is to develop a width stretching unit in which the width stretching effect achieved is maintained positively over a certain travel of the web of material. The width stretching unit is of the type having a first needle disc unit having first and second needle discs disposed along a first axis at an axial distance corresponding to a width of the web of material, the first and second needle discs having a multiplicity of peripherally distributed needles pointing radially outward. The multiplicity of needles are intended for insertion into selvedges of the web of material. The stretching unit also includes a pivoting mechanism for pivoting a first rotational axis and a second rotational axis of the first and second needle discs, respectively, in a pivoting plane passing through the first axis. The stretching unit further includes a pinning mechanism for pinning the web of material by its edges onto the multiplicity of needles of the first and second needle discs in a region of reduced axial distance between edges of the first and second needle discs.
Maintaining the width stretching effect over a certain travel of the web of material is achieved by the present invention which includes a second needle disc unit associated with the first needle disc unit, the second needle disc unit having a second axis parallel to the first axis and situated in the pivoting plane, the second needle disc further having third and fourth needle discs rotatably mounted substantially perpendicular to the second axis, the third and fourth needle discs rotating about the second axis at the same peripheral speed as the first and second needle discs, an axial distance between the third and fourth needle discs being equal to the axial distance between the first and second needle discs in a zone of increased distanc

REFERENCES:
patent: 88505 (1869-03-01), Palmer
patent: 148082 (1874-03-01), Palmer
patent: 4494740 (1985-01-01), Noboru et al.
patent: 5042121 (1991-08-01), Young, Jr.
patent: 5259097 (1993-11-01), Aihara et al.
patent: 5555610 (1996-09-01), Young, Jr. et al.

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