Stock material or miscellaneous articles – Hollow or container type article – Polymer or resin containing
Reexamination Certificate
1997-10-01
2002-12-17
Nolan, Sandra M. (Department: 1772)
Stock material or miscellaneous articles
Hollow or container type article
Polymer or resin containing
C087S006000, C087S009000, C138S123000, C138S124000
Reexamination Certificate
active
06495227
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to braided tubular structures, processes and machines for manufacturing them, and their applications in the construction of plane armorings for composite material.
2. Background Art
European Patent EP-A-0 113 196 Published Patent Application No. A-0113196 has already disclosed a braided (and nonwoven) tubular structure, which is intended to form a composite tubular part after impregnation with resin and polymerization of the latter. This tubular structure includes longitudinal threads (parallel to the axis of said structure) and helicoidal braiding threads forming two grids of directions oblique in relation to said longitudinal threads, said braiding threads being interlaced with one another, as well as with said longitudinal threads. These longitudinal threads are distributed on a plurality of collars coaxial with the structure and the helicoidal braiding threads follow paths which cause them to pass between the longitudinal threads of one or of a plurality of concentric collars, these paths being such that the projections of said braiding threads onto a plane orthogonal to the axis of the tubular structure are broken lines, all the sections of which are oblique in relation to the thickness of the wall of said tubular structure.
It is possible in this way to obtain braided tubular structures of considerable wall thickness. However, in spite of this, the mechanical wall characteristics of the tubular composite parts constructed from these tubular structures are relatively low, since these tubular structures exhibit numerous voids due to the intersections of the paths of the helicoidal threads of one and the same direction.
BROAD DESCRIPTION OF THE INVENTION
The object of the present invention is to remedy this disadvantage.
To this end, according to the invention, the braided tubular structure including longitudinal elongate elements distributed on a plurality of collars coaxial with the structure and braiding threads forming two grids of directions oblique in relation to said longitudinal elongate elements and interlaced with said longitudinal elongate elements, said braiding threads following paths which cause them to pass between said longitudinal elongate elements, is noteworthy in that said braiding threads of each one of said grids form an assembly of superposed layers in which said braiding threads are parallel from one layer to the next.
Thus, said parallel braiding threads, which form layers which are superposed in the direction of the thickness of the wall of said tubular structure, permit the minimization of the intersections and thus the imparting of excellent mechanical properties to said wall.
Said longitudinal elongate elements may be threads as in the European published patent application identified hereinabove. They may likewise be composed of thread rovings, of cables, of rods, of tubes, etc . . . .
In order to be able to construct such a tubular structure, it is advantageous, in accordance with the present invention, to braid it by means of a plurality of braiding threads which are wound off from so many spools which are displaceable through a succession of elementary paths that said braiding threads should become interlaced with elongate elements which are parallel to one another and distributed on a plurality of coaxial collars. According to the invention, this process is noteworthy in that said spools are displaced with the aid of three types of elementary paths, that is to say first elementary paths of direction orthogonal in relation to said coaxial collars, second elementary paths of direction circumferential in relation to the latter and third elementary paths, each one of which associates a first and a second elementary path inter se.
Thus, said first elementary paths permit said braiding threads to be caused to pass around said elongate elements of different collars, that is to say within the thickness of the wall of said tubular structure, while said circumferential second paths permit the constitution of said superposed layers formed of threads which are parallel from one layer to the next.
It will be noted that, by varying the sequence of said elementary paths, it is possible to vary the braiding “mesh”. Thus numerous sequences of different elementary paths are possible and, by virtue of the invention, it is possible to obtain a large number of different “meshes” for the tubular structure of the present invention.
For the implementation of such a process, the present invention advantageously provides a braiding machine including a set of identical multiindented wheels, mounted on a fixed support and driven in rotation to cause the circulation of spindles carrying spools of braiding threads, said multiindented wheels being disposed in parallel and equidistant lines. In order to be capable of executing the three types of elementary paths which are characteristic of said process, this machine is, according to the invention, noteworthy:
in that, in said set of multiindented wheels:
the multiindented wheels belonging to a line are spaced from one another, so that two consecutive multiindented wheels belonging to one and the same line cannot cooperate directly with one another;
a multiindented wheel belonging to one line is disposed between two multiindented wheels belonging to an adjacent line and cooperates with said two multiindented wheels; and
in that, in the spaces between the consecutive multiindented wheels of a line, there are provided passages for said longitudinal elongate elements of said braided tubular structure.
The result is accordingly a quincuncial arrangement for the multiindented wheels and for said passages, said quincunces of multiindented wheels being overlapped with said quincunces of said passages. Within such quincunces, the distance between the centers of two consecutive multiindented wheels of a line is equal to the distance between two consecutive passages of a line, these distances being equal to twice the distance between two adjacent lines of multiindented wheels and of passages.
By virtue of such a quincuncial arrangement, it is possible to cause the circulation of said spindles transversely and parallel to said lines of multiindented wheels, and also to cause them to turn about the center of a multiindented wheel, so that it is possible to execute the three types of elementary paths mentioned hereinabove.
To do this, according to another feature of the present invention, in said spaces between the consecutive multiindented wheels of a line, there are further provided rhomboidal needles of controlled orientation which are intended to direct said spindles to cause them to pass from one multiindented wheel to another belonging to an adjacent line (first and second elementary paths) or to maintain them on their respective multiindented wheels (third elementary paths).
Preferably, said needles are coaxial with said passages for the elongate elements, so that they likewise form quincunces, which are superposed upon those of said passages.
Said needles can be controlled in orientation by a linkage gear.
Preferably, at each instant:
all the needles associated with a line of multi-indented wheels are parallel to one another and thus have a common orientation; and
the common orientations of the needles associated with two adjacent lines of multiindented wheels are symmetrical with respect to one another in relation to said lines.
Said fixed support of the multiindented wheels may be plane. Nevertheless, for reasons associated with braiding mesh clamping, it is advantageous that said plane support should be cylindrical. In this case, said plane support may be constituted by the internal wall of a cylindrical collar. Such a collar may have its axis disposed vertically or horizontally.
Moreover, French Patents FR-A-2 610 951 and FR-A-2 610 952 have already disclosed a plane woven armoring for composite material including weft threads distributed on a plurality of superposed levels and warp threads passing around weft threads situated at different l
Aerospatiale - Societe Nationale Industrielle
Fisher Christen & Sabol
Nolan Sandra M.
LandOfFree
Braided tubular Structure for a composite part its... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Braided tubular Structure for a composite part its..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Braided tubular Structure for a composite part its... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2972190