Abstracts of patents Abstracts of UK and US patents are prepared by Dr F.R. Jones and Dr R.J. Hand of the University of Shefield, UK

UK PATENTS

Method for manufacturing composite material (BP Chemicals Ltd, UK) GB 2 239 835 A (I 7 July 1991)

Perforated lightweight structures from fibre- reinforced composites are described. The perforations are formed in situ and arise from the use of needles in the mould. The previous difficulties with removing the article from the mould have been overcome by incorporating a stripper plate. The article is removed from the mould with the stripper plate. The latter has been engineered by ensuring the plugs of resin which form keep the component anchored to the stripper plate.

Games racket frame (Dunlop Ltd, UK) GB2240 302 A (31 July 1991)

The invention refers to problems of incorpor- ating string holes in a compression moulded thermosetting composite frame. A polyphenyl- oxide thermoplastic (PPO) grommet strip is injection moulded and placed in the mould along with tubular members of resin impreg- nated fibres (e.g. carbon) on an inflatable mandrel. The PPO adheres to the cured resin after moulding.

(Honda Giken Kogyo Kabushiki Kaisha) GB 2 241 194 A (28 August 1991)

Preventing breakage of covering film during sheet forming and curing of fibre reinforced resin

The title problem can bc avoided in vacuum moulding, by applying a sheet forming pressure to the film and the fibre (glass or carbon) resin sheet via a silicone rubber membrane or by initiating cure of the resin adjacent to the film prior to the majority of the resin, by means of ultra-violet light, hot wind or other mechanism such as cooling of the film.

Moulding rackets (Cinpres Ltd. UK) GB 2 241464 A (4 SeD- tember 1991)

A games racket (e.g. tennis) is moulded by gas assisted injection moulding to produce a double hollw cored moulding. Furthermore, the fibre reinforced thermoplastic flows through the mould from one handle around the periphery enabling a preferred directional- ity to the fibres to be achieved. The head may include a separately or integrally moulded throat member. The connecting of the separate throat or the two handles may be achieved with a snap fit or other joining mechanism such as, for the latter, a sleeve. Stringing holes can also be incorporated into head during moulding.

Laying-up table (Dowty Aerospace Gloucester Ltd, UK) GB 2 244 453 A (4 December 1991)

A laying up table for use in the manufacture of multilayer composite articles is described. The gap between the two table components can be adjusted between pplication of each laminae so that when a lug section is formed by bending the prepreg through 180”, no wrinkling occurs.

Moulding a mould and a mould liner skin of composite material for moulding an article of composite material (British Aerospace plc, UK) GB 2 243 IO7 A (23 October 1991)

The use of a mould, made from a composite material of similar composition to the moulding, improves the surface finish by removing the differential shrinkage between mould and moulding, which is responsible for poor surface finish. This can be achieved by using an intermediate skin of carbon fibre reinforced composite between the composite mould member (s )

US PATENTS

Method for making 3D fibre reinforced metal/glass matrix composite article Spain R.G. (Airfoil Textron Inc., Lima, Ohio, USA) US Pat 4 916 997 (17 April 1990)

A plurality of braiding fibre bundles and stuffing fibre bundles each comprised of a reinforcing fibre overwrapped by matrix forming fibres are arranged so that they extend from a braiding device. The braiding fibre bundles are moved in a braiding pattern relative to one another and the stuffer fibres to form a braided preform and the whole is subjected to temperature and pressure so that the matrix forming fibres form a matrix enclosing the reinforcing fibres and keeping them separate from one another.

Process for the continuous production of manufactured articles reinforced with mixtures of hydraulic binders Vittone A., Chiappini G., Magra A. and Di Paola M. (Mopfelan S.p.A., Milan, Italy) US Pat 4 917 749 (17 April 1990)

A thin layer of hydraulic binder mix and a net-like structure are both fed to a single porous conveyor belt. The reinforcing net is immersed and impregnated into the thin mix layer and compacted with the binder. Excess water is extracted until the water content is between 15 and 40% with respect to the dry product. This is followed by successive feeding

of additional layers of hydraulic binder mix alternated with nets of fibrilled polyolefinic films to form a plate. This is subsequently compacted and the water extracted, the final extraction occurring under vacuum, all on the one conveyor belt.

Machine for manufacturing composite rein- forcement elements woven in three dimensions Cahuzac G.J.J. and Monget F. (Aerospatiale Societe Nationale Industrielle, Paris, France) US Par 4 917 756 (17 April 1990)

A machine for manufacturing composite reinforcement elements woven in 3D from textile, mineral, synthetic or other fibres. The machine is comprised of a frame, a mount for a disposable foam mandrel, which has externally the internal shape of the desired reinforcing element, and an arm above the mandrel adjustable along three orthogonal axes and with mounts for various work devices. There is also a means for implanting rigid members in the mandrel and for applying to its surface successive layers of threads or fibres which are superimposed and crossed in at least two directions along with means for interconnecting these layers with threads or fibres that extend through the layers.

Method of making composite tread for track-laying vehicles Savage R.C., Zeller G.P. and Shirka M.D. (General Motors Corporation, Detroit, MI, USA) US Pat 4 919 876 (24 April 1990)

Abrasion resistant fibre bundles are placed in a lower mould member such that the fibres are perpendicular to the mould. The bundles are arranged in elongated rolls formed by rolling narrow webbing of polyaramid fibre bundles interwoven with polyester fibre bundles running in the transverse direction. A metal support member is placed on top of the fibre bundles and the mould is closed. A quantity of reaction injection mouldable polymeric material is injected into the cavity thus embedding the fibre bundles and the metal support member. The whole is cured before demoulding.

Making diamond composite coated cutting tools McCune R.C. and Baird R.J. (Ford Motor Company, Dearborn, MI, USA) US Par 4 919 974 (24 April 1990)

Chemical vapour deposition of separated diamond or diamond-like particles onto a nondiamond or nondiamond-like substrate is initiated by the use of low pressure metastable deposition of carbon in the presence of atomic hydrogen at a temperature that favours the nucleation of such particles. Nucleation of additional particles before the formation of a contiguous film is suppressed whilst the

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