Production of a shaped filamentary structure

Abstract

The invention is concerned with a method and apparatus for producing a shaped filamentary structure and more particularly, to filamentary structures which can be subjected to further processing to produce a carbon-carbon product. A specific use of the invention is in the production of discs for use in aircraft braking systems. The method includes needle punching a unidirectional layer of filaments to give a degree of dimensional stability; cutting a plurality of segments from the layer of needle punched filamentary material; assembling a plurality of segments in side-by-side contiguous relationship to produce a filamentary layer of the required structural shape; superimposing at least one similar layer on the first layer and needle punching the assembled layers to produce cross-linking of the layers. In the preferred method of carrying out the invention, the layers of filamentary material are supported by a sub-structure which permits needle penetration, and this sub-structure is peeled off the final needle punched assembly. A further preferred feature includes assembling the segments in a former and rotating the former relative to a reciprocating needling head. The invention also comprises an apparatus for producing a shaped filamentary structure comprising an open-topped receptacle for the assembled segments; a needling head located over only part of the receptacle means for rotating the receptacle to bring a complete annulus of the filamentary segments in it under the needling head and a support located inside the receptacle and means for rotating the support with the receptacle, and lowering the uspport relatively to the receptacle during the needling operation.