Textiles: spinning – twisting – and twining – Apparatus and processes – Covering or wrapping
Reexamination Certificate
2000-02-24
2003-04-08
Worrell, Danny (Department: 3765)
Textiles: spinning, twisting, and twining
Apparatus and processes
Covering or wrapping
C057S003000
Reexamination Certificate
active
06543213
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention is directed to a method for manufacturing ropes, cables or the like, whereby an envelope of a flexible, web-shaped material, for example paper, is produced around at least one central core, for example a conductor, moved in the direction of its longitudinal axis, and the structure that has arisen in this way is stranded in a traditional way while being moved, for example with a SZ stranding, whereby at least one further layer of plastic material can also be applied onto the moving, stranded structure in any case, preferably by extrusion; the invention is also directed to an apparatus for the implementation of the method, i.e. for the manufacture of ropes, cables or the like, comprising a means for moving a central core, for example a conductor, in the direction of its longitudinal axis, delivery means for a flexible, web-shaped material, for example paper, in the immediate proximity of the moving core and parallel thereto, and comprising at least one following guide means for forming a closed envelope of the web-shaped material around the core, as well as a stranding mechanism, for example an SZ stranding mechanism, and, in any case, also at least one extrusion means for applying a further layer of plastic material onto the moving, stranded structure.
There are many applications wherein a rope, a cable or the like must be manufactured in such a way that an envelope is produced around the central core by stranding, whereby an intermediate layer composed of a thin, typically web-shaped material is also provided between this core and the envelope. For instance, the ground conductor in electrical cables is often wrapped with paper, after which the stranding occurs. This can ensue, for example, with the method of SZ stranding, whereby the conductors are conducted through a perforated disk with rapidly changing rotational sense, so that the drums for the fibers of the envelope need not be moved around the central core. There are, however, other methods where this occurs and that thereby produce a stranding with only one rotational sense. In order to then apply the intermediate layer of paper onto the central core or, respectively, the conductor, it has already been proposed to wrap a paper strip around the core oriented obliquely relative to the longitudinal axis of the cable; this, however, causes particular difficulties given extremely high-speed systems. Paper strips that are supplied in longitudinal direction and run with the speed of the cable have likewise been disclosed, these being folded once in length and around the central core. It is thereby disadvantageous that this envelope is not symmetrical around the longitudinal axis of the cable and is also open at one side, so that problems relating to the complete covering of the core derive over and over again, specifically in high-speed systems.
SUMMARY OF THE INVENTION
An object of the present invention was therefore to improve a method of the type initially cited such that, while avoiding the above-described disadvantages and problems of the prior art, a complete and dependable envelope of a central core can be produced before a following stranding, even given systems that run at high speed and continuously and given systems with changing rotational sense of the stranding. A further goal of the invention was to implement an apparatus as initially set forth such that a complete and dependable enveloping of a central core can be produced in a fast and dependable way before a following stranding and such that it is suitable for very fast operation, i.e., fast and continuous throughput of the cable, even with changing rotational sense of the stranding.
For achieving the first object, the initially described method is characterized in that the material for the envelope is supplied in the form of a band with the same speed and, finally, is directed parallel to the core, such that at least two longitudinal structures that are essentially parallel to one another and to the longitudinal axis of the band and that reduce the flexural strength of the band are worked into the band, and such that the band, following the alignment parallel to the core and before the stranding, is automatically bent around the core at least twice at its longitudinal structures such that a closed sheath arises around the central core. Due to the equally fast delivery of the material for the envelope and the parallel alignment, the delivery speed need not be any higher than the throughput speed of the cable through the system, so that very high values thereof can be achieved. Working the longitudinal structures in, which reduces the risk of tearing, is thereby still possible in a relatively simple way. The two-time bending or, respectively, folding of the band in longitudinal direction yields a hollow profile structure, at least a structure with a triangular cross section of the material of the envelope that surrounds the core without gaping regions and, thus, dependably covers it on all sides and that is also not pressed open during the course of the following stranding.
It is provided according to a further feature of the invention that the longitudinal edges of the band lying opposite one another overlap after being bent around the core. The hold of the closed structure completely enveloping the core is thus improved further and a gaping thereof is prevented to the farthest-reaching extent.
The most dependable hold of the hollow structure composed of the structure folded or, respectively, bent around the central core in longitudinal direction is established when the overlapping longitudinal edges of the band are joined to one another at least at points. This can be achieved, for example, by gluing, punctiform as well, or by any other desired joining technique such as basting, sewing, clamping, etc.
The simplest processing for preserving a closed structure around the central core can be achieved in that at least two grooves are produced as longitudinal structures. The band can then be folded twice in the same direction in the region of these grooves, so that a hollow structure with a triangular cross section arises, which, given a corresponding arrangement of the grooves, can also be fashioned symmetrically with respect to its longitudinal axis.
It is advantageously provided according to a further feature of the invention that a plurality of grooves are produced on both sides of the band and the band is multiply folded, and that, during the course of bending the folded band around the core and the overlapping of the longitudinal edges, at least one groove of a longitudinal edge engages into a groove of the longitudinal edge lying opposite. A tighter wrapping of the central core with less unused cross section and, thus, a reduced need for material is thereby possible. Due to the plurality of grooves, the bending and, thus, the stressing of the material in the region of each and every groove is lower, so that a greater protection against damage is established, this being of particular significance given high-speed systems.
Given the aforementioned version of the method, an optimum protection against unwanted unraveling or gaping of the envelope can be achieved in that an overlap of a plurality of grooves is produced at each longitudinal edge. Of course, an at least punctiform, additional joining by gluing, basting, sewing or similar methods is thereby also advantageous and additionally enhances the durability of the envelope.
As provided in an advantageous version of the invention, grooves having a v-shaped cross section can be especially simply and easily formed.
It is provided according to a further feature of the invention that the envelope of the band-shaped material that surrounds the central core and is already closed is guided at essentially all sides between at least one location at which the completely closed configuration has been essentially achieved and the entry into a following stranding device. Particularly for high-speed stranding systems, maintaining the closed configuration and protection against su
Hurley Shaun R
Peter Khu Sondermaschinenbau GmbH
Sonnenschein Nath & Rosenthal
Worrell Danny
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