Forming fabric for use in a paper machine, and method and apparatus for manufacturing such a forming fabric - Patents

Forming fabric for use in a paper machine, and method and apparatus for manufacturing such a forming fabric
Patent Agent: Berenato, White & Stavish, LLC - Bethesda, MD, US
Patent Inventors: Walter Best, Christian Molls, Paul Wales
Applicaton #: 20070028997
Class: 13938300R (USPTO)
02/08/07

The present invention relates to a forming fabric (2), for use in the sheet-forming section of a paper machine, having or comprising a textile planar structure in which, in order to enhance inherent stability, crossing yarns (5, 6, 7) are engaged into one another at crossing points (14) and in which yarns (5, 7) additionally are fused to one another, which is characterized in that the planar structure comprises crossing first and second yarns (5, 7), the first yarns (7) having the property that they absorb laser energy and can be brought, by absorbed laser energy, to melting temperature at least at the surface; and that first and second yarns (5, 7) are fused to one another at at least some of their crossing points (14).

SUMMARY OF THE INVENTION
[0010] It is the object of the invention to manufacture a forming fabric of the kind cited initially more economically, preferably without producing structural changes. A further object is to make available a method suitable for manufacture, and an apparatus therefor.
[0011] The first object is achieved, according to the present invention, by a forming fabric in which the planar structure comprises crossing first and second yarns, the first yarns having the property that they absorb laser energy and can be brought, by absorbed laser energy, to melting temperature at least at the surface; and in which first and second yarns are fused to one another at at least some of their crossing points. For many situations it is sufficient if only some of the first and second yarns are welded to one another, and those only at some of their crossing points.
[0012] The basic idea of the invention is therefore to use for some of the yarns, in the context of a forming fabric, particular yarns which are distinguished by the fact that they absorb laser light. In this fashion, the textile planar structure can be additionally stabilized by the fact that the first yarns are heated by means of a laser to melting temperature, and at at least some of the crossing points (if not at all) a fused join is thus produced with the second yarns, which absorb only little or no laser light.This manner of producing the fused join is substantially less time-consuming and energy-intensive than the known methods, especially since the first yarns themselves require little additional cost. A further advantage consists in the fact that the dimensional stability can be individually adapted to particular requirements by correspondingly varying the number of first yarns as well as the number of crossing points at which welding or fusing is performed. This is because in many cases, a forming fabric that is too stiff and therefore insufficiently adaptable is also disadvantageous.
[0013] In an embodiment of the invention, provision is made for the yarns otherwise not to be joined to one another, i.e. for no further joint to exist beyond the mutual engagement of the yarns and their single-point welding at crossing points.
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