GB2430644A

GB2430644A - Method of moulding a composite article comprising a reinforcement

Info

Publication number: GB2430644A
Application number: GB0613358A
Authority: GB
Inventors: Steven Cousins; David Payne; Andrew Mills
Original assignee: Coretex Structures Ltd
Current assignee: Coretex Structures Ltd
Priority date: 2005-07-05
Filing date: 2006-07-05
Publication date: 2007-04-04
Anticipated expiration: 2026-07-05
Also published as: GB2430644B; GB0613358D0; GB0513732D0

Abstract

A method of moulding a composite article (21) having a reinforcement (18) comprises the steps of locating a first element (12;14) of a clamp assembly (10;13) in a mould (16), locating at least one reinforcement (18) in said mould (16) (10 and 16 figure 3A - not shown), locating a second element (12') of the clamp assembly (10) in said mould (16) such that the reinforcement (18) lies between said first and second elements (12;14), closing the mould; curing resin deposited around the reinforcement. A clamp assembly for use in the method comprises a recess (17) configured to accommodate at least one reinforcement (18) extending substantially in a longitudinal direction (XX), the walls (15) (figure 1 - not shown)of said recess (17) extending at an angle to the longitudinal direction in the range of about 5 degrees to about 20 degrees.

Description

1 2430644 TITLE: METHOD OF MOULDING A COMPOSITE ARTICLE

COMPRISING A REINFORCEMENT

DESCRIPTION

TECHNICAL FIELD

The present invention relates to methods of moulding a composite article comprising a reinforcement and methods of attaching such composite articles to other, possibly dissimilar, materials. It relates particularly, although not exclusively, to the attachment to metal of a composite moulded article of the kind disclosed in WO01/14128.

BACKGROUND ART

WO0l/14128 discloses an elongate cored reinforcement of constant crosssection comprising an envelope of strength-giving fibres surrounding a core of expansible material. Such a reinforcement can be used in a method of moulding, also disclosed in WOO1/14128, which includes laying down the reinforcement in and along the channels of a mould by repeated passes along the channels to at least partially fill the channels, closing the mould and curing resin provided around the reinforcement. After closing, S the interior of the mould may be subject to reduced pressure to cause expansion of the reinforcement to reduce void space within and around the reinforcement. Reducing pressure may also serve to draw or infuse resin into the mould. The mould may be a nodal mould, in which case the reinforcement may be deposited across the nodes thereof.

It is often desirable to attach composite articles of the kind described above to other materials in a cost- effective and reliable fashion.

DISCLOSURE OF INVENTION

According to the present invention, there is provided a method of moulding a composite article comprising a reinforcement, the method comprising the steps of: locating a first element of a clamp assembly in a mould; locating a reinforcement in said mould; locating a second element of the clamp assembly in said mould such that the reinforcement lies between said first and second elements; closing the mould; and curing resin deposited around the reinforcement.

Locating the reinforcement in the mould prior to attaching the second element of the clamp assembly allows the reinforcement to be accurately laid up in the clamp.

An open clamp assembly is also more easily filled by machine of the kind disclosed in the aforementioned The resulting clamp provides an interface between the moulded article and metal. Attachment between the clamp and the metal can then be achieved by welding, bolting, bonding or other conventional joining method. Since the clamps fit into the tooling in which the moulded article is shaped, they provide a secure bond between the moulded article and the adjacent, typically metal faces of the clamp. These faces may also be roughened or have projections on them to improve the attachment of the metal to the fibre and matrix composite.

Advantageously, the method comprises the steps of locating a plurality of reinforcements in said mould and locating the second element of the clamp assembly in said mould such that said plurality of reinforcements lie between the first and second elements.

The reinforcement may have an expansible core which, after closing the mould, may be expanded prior to curing the resin. This may reduce voids which might otherwise fill with resin and reduce the strength to mass ration of the composite article.

The first and/or second elements may have at least one hole through which resin may flow around the reinforcement, thereby effecting a bond between the material of the clamp, typically metal, and the reinforcements.

At least the first element may have a recess configured to accommodate at least one reinforcement. The walls of the recess may extend at an angle to the longitudinal direction of extension of the reinforcement, the angle being in the range of about 5 degrees to about degrees.

The first and/or second elements may also be configured to be attached, e. g. by welding, bolting, bonding or other joining method, to a further member other than said composite article.

The invention also provides a method of manufacturing an assembly comprising a composite article and a further member, the method comprising the steps of moulding a composite article according to any preceding claim and attaching a further member to said clamp assembly.

The invention also provides a clamp assembly for use with the methods outlined above and comprising a recess configured to accommodate at least one reinforcement extending substantially in a longitudinal direction, the walls of said recess extending at an angle to the longitudinal direction in the range of about 5 degrees to about 20 degrees.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described by way of example by reference to the following diagrams, of which: Figure 1A is a plan view of a first embodiment of an element of a clamp assembly for implementing the present invention; Figure lB is a sectional view taken through line XX of figure 1A; Figures 2A and B are plan and sectional views respectively of a second embodiment of an element of a clamp assembly for implementing the present invention; Figures 3A and B are plan and sectional views respectively of the element of figure 1 being used in the method of the present invention; Figure 4A is longitudinal sectional view of a composite strut or beam incorporating the clamp assemblies of figures 1 and 2; Figure 4B is a detailed sectional view taken through element 14 along the longitudinal axis L-L of the beam.

Figures 5A and B are plan and sectional views respectively of a third embodiment of a clamp assembly being used in the invention;

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Figure 1 shows one element 12 of a first embodiment of a clamp assembly 10 configured to be welded to a tubular metal member (not shown) along semicircular attachment surface 11. Figure 2 shows one element 14 of a clamp 13 according to a second embodiment configured to be bolted (via hole 30) to a metal member.

As shown in figure 3A, one element 12 of a clamp 10 is placed into each end of the mould tooling 16. Elongate cored reinforcements 18 are then deposited into the mould tooling 16 in accordance with the aforementioned WO01/14128, with each reinforcement 18 also being placed into a recess 17 of a clamp element 12. One possible termination of the reinforcements in a clamp is shown at in figure 3.

As shown in figure 3B, the second element 12' of each clamp is now fitted to the first element 12 and attached thereto, e.g. by screws passing through holes 22, so that some force is inherently applied to compress the reinforcements 18. At this stage the clamps and reinforcements stand proud of the tooling. The mould tooling 16 is now closed by fitting an upper part (not shown) and clamping it in place.

As known from WO01/14128, resin is then injected or otherwise introduced into the mould and then cured to create a moulded article. Infusion ports 24 are included in the clamps so that resin can flow around the critical faces to effect the bond between metal of the clamp and reinforcements.

Figure 4 illustrates an alternative arrangement in which at least some of the reinforcements 18 do not actually terminate, i.e. have ends, in a clamp 14 but instead pass through the clamp in a continuous loop 19 to create a beam 21.

In both embodiments of clamp, the angle of the walls of the recess 17 relative to the longitudinal axis (XX in figures 1 and 2) is chosen to be sufficiently small that the resin bond between the reinforcement and the clamp is loaded in shear rather than in tension. However, too small an angle will result in clamp walls that are thin and thus of inadequate strength. Angles in the range of about 5 to about 20 degrees have been found to offer the best compromise.

Bonding between metal and reinforcement may be further enhanced by the mechanical force applied by the clamping faces and mechanical barbs on the internal faces of each recess 17 which oppose any force acting to separate the moulded article from the clamp. The clamp may also be formed with a constriction or bottleneck: the resulting wider portion of moulcied article to either side of the constriction acting as a physical barrier to retain the infused reinforcement in the clamp even in the event of bond failure. Such a constriction is shown at 23 in figures 4A and B and may be at the mouth of the recess as shown or further along into the recess in the longitudinal direction LL.

Figures 5A and B are plan and sectional views respectively of a further variant which allows reinforcements 18 to pass though a metal clamp to allow clamping at the side. The mould tool 16 is formed with a recess 30 into which a U-shaped metal fixture 32 is placed. One or more reinforcements 18 are then laid in the fixture in the normal manner. A top plate 34 is then inserted into the open top of the fixture and held in place e.g. by barbs formed on the sides 36 of the top plate and/or the inner faces 38 of fixture 32. The top plate 34 is additionally provided with a threaded hole 40.

This is preferably plugged prior to the mould being closed and filled with resin which is then cured in the normal manner. After curing, hole 40 can be unplugged to provide a means by which external items such as brackets can be attached to the moulded item.

To make a complex structure such as a car body, each of the pillars which provide the structure of the upper car body (e.g. the door surround and the windscreen surround, which may also be connected along the roof rail) can be terminated into metal clamps as described above and welded, bonded or otherwise attached to the remaining metal structure of the car which might be considered a car platform. To this end, the attachment surface of the clamp assembly may be shaped to fit the attachment point, for example the semicircular attachment surface 11 of the embodiment of figure 1A for attachment to a tubular member 29 as shown in figure 4. Multiple configurations of composite thus allow multiple vehicle types to be derived from a common basal platform in metal and upper pillar structures in composite.

It should be understood that the invention has been described by way of examples only and that wide variety of modifications can be made without departing from the scope of the invention. Thus, whilst pairs of identical clamp elements have been shown, such elements need not be identical and may incorporate mutual locking or locating features. Similarly, whilst two-part clamp assemblies have been illustrated, clamp assemblies may comprise more than two elements between which the reinforcement is located.

Moreover, whilst the clamp assembly may comprise means to apply pressure to the reinforcement, e.g. screws passing through holes 22 in the embodiment of figure 3B above, this need not be the case: pressure may instead be applied to the inside of the reinforcement e.g. by an expansible core of the kind known from the aforementioned WO0]./14128. In such circumstances, the clamp assembly simply provides a reaction to this internal pressure.

Claims

1. Method of moulding a composite article comprising a reinforcement, the method comprising the steps of: locating a first element of a clamp assembly in a mould; locating a reinforcement in said mould; locating a second element of the clamp assembly in said mould such that the reinforcement lies between said first and second elements; closing the mould; and curing resin deposited around the reinforcement.

2. Method according to claim 1 and comprising the steps of locating a plurality of reinforcements in said mould and locating the second element of the clamp assembly in said mould such that said plurality of reinforcements lie between the first and second elements;

3. Method according to any preceding claim and comprising the steps of locating in said mould at least one reinforcement having an expansible core, closing the mould, expanding said core and curing resin deposited around the reinforcement.

4. Method according to any preceding claim and comprising the steps of locating in said mould first and/or second elements having at least one hole, closing the mould and causing resin to flow through said hole and around the reinforcement.

5. Method according to any preceding claim and comprising the steps of locating in said mould a first element having a recess configured to accommodate at least one reinforcement.

6. Method according to claim 5 and comprising the steps of locating in said mould a first element having a recess configured to accommodate at least one reinforcement extending substantially in a longitudinal direction, the walls of said recess extending at an angle to the longitudinal direction in the range of about 5 degrees to about 20 degrees.

7. Method according to any preceding claim and comprising the steps of locating in said mould first and/or second elements configured to be attached to a further member other than said composite article.

8. Method of manufacturing an assembly comprising a composite article and a further member, the method comprising the steps of moulding a composite article according to any preceding claim and attaching a further member to said clamp assembly.

9. Clamp assembly for use in the method of any preceding claim and comprising a recess configured to accommodate at least one reinforcement extending substantially in a longitudinal direction, the walls of said recess extending at an angle to the longitudinal direction in the range of about 5 degrees to about 20 degrees.