This invention relates to a connection arrangement for use in applying or securing a fitting to an end part of a shaft, for example of a composite material.

The attachment of fittings to composite materials is problematic as the drilling of holes or the like therein can significantly weaken the composite material. Consequently, fittings are sometimes attached to composite material shafts or tubes by clamping the wall of the tube or shaft between a pair of components. One technique used in the attachment of a fitting to an end part of a composite material shaft is to form the shaft in such a manner as to include an end part of tapering form, a wedge member being located within the tapering end part of the shaft. The wedge member is internally screw threaded, and a screw threaded part of the fitting is threadedly mated with the wedge member. An outer collar of internally tapering form encircles the end part of the shaft. The fitting is provided with an outwardly projecting flange, and screws or bolts are threadedly mounted to the flange, the screws or bolts engaging and applying a load to the collar to drive the collar axially towards the wedge member such that the tapering end part of the shaft is clamped between the wedge member and the collar.

Such an arrangement allows the application of compressive or tensile loads to the shaft by way of the fitting. However, there is a risk that, in use, the screws or bolts may work loose, reducing the clamping load and hence impairing the integrity of the connection by which the fitting is attached to the shaft. Furthermore, the assembly operation is relatively complex, and achieving a desired clamping load may be difficult.

It is an object of the invention to provide a connection arrangement by which a fitting may be applied to or secured to a shaft in which at least some of the disadvantages associated with known arrangements are overcome or are of reduced impact. According to the present invention there is provided a connection arrangement comprising a wedge member secured to or forming part of a fitting, the fitting including an outwardly extending flange, a collar encircling part of the wedge member and defining, with the fitting and the flange thereof, an annular chamber, and a resin material element located within the annular chamber.

In use, with the wedge member located within a tapering end portion of a shaft, for example of composite material form, the resin material element may be used to apply a clamping load to the collar, urging the collar axially towards the wedge member, clamping the tapering part of the shaft between the wedge member and the collar.

Where the shaft is of composite material form, it may include reinforcing fibres wound over the wedge member. The wedge member can cause the shaft to include an end section of increased diameter, part of the end section defining the tapering end portion of the shaft. Alternatively, the tapering end section may be of reduced diameter compared to the remainder of the shaft.

The flange and/or collar is preferably provided with a passage or a plurality of passages communicating with the annular chamber through which resin material is supplied, in use, to form the resin material element.

The invention also relates to a method of connecting a fitting to a shaft, the method comprising the steps of providing a wedge member secured to or forming part of a fitting, wedge member being located within a tapering end part of the shaft, the fitting including an outwardly extending flange, a collar encircling part of the wedge member and defining, with the fitting and the flange thereof, an annular chamber, supplying a resin material to the chamber and curing or allowing the resin material to cure or set to form a resin material element located within the annular chamber.

The resin material may be applied under pressure to apply a compressive load to the collar, the resin material preferably being cured or allowed to cure or set whilst under pressure. Alternatively, an external biasing load may be applied to the collar, the load being maintained whilst the resin material is supplied and cured or allowed to cure or set.

The invention will further be described, by way of example, with reference to the accompanying drawing, Figure 1, which is a diagrammatic representation of a connection arrangement in accordance with an embodiment of the invention.

The connection arrangement shown in Figure 1 is intended for use in connecting or securing a fitting 10 to an end part of a tube or shaft 12 of composite material form. The tube or shaft 12 is provided with an end section 14 of tapering form. The manner in which the tapering end section 14 is formed falls outside of the scope of the invention, and so will not be described herein in detail, save to note that several techniques for forming such a tapering end section 14 are known and would be familiar to the man skilled in the art.

Located within the tapering end section 14 is a wedge member 16. The wedge member 16 is internally screw threaded, and is threadedly mounted to an end part of the fitting 10. The outer periphery of the wedge member 16 defines a wedge shaped surface of generally conical form having a profile substantially matching the internal profile of the end section 14 of the tube or shaft 12.

Whilst a threaded connection represents a convenient way of securing the wedge member 16 to the fitting 10, other connection techniques are possible. Indeed, the wedge member 16 could be integrally formed with the fitting 10 if desired.

Integrally formed with the fitting 10, or rigidly attached to the fitting 10 by any suitable technique, is an outwardly extending flange 18.

The connection arrangement further comprises a collar 20 that encircles part of the fitting 10 and the wedge member 14. The collar 20 is shaped to define a cylindrical outer wall 22 defining a chamber or recess within which the flange 18 is located, the fitting 10, including the flange 18, and the collar 20, including the wall 22, together defining an annular chamber 24. The fit of the flange 18 with the wall 22 is such that the chamber 24 is reasonably well sealed. Alternatively, the design of the flange 18 and collar 20 may be such that an end part of the collar 20 is received within a recess or the like formed in the flange 18.

As illustrated, a flow passage 26 is provided in the flange 18, the flow passage 26 communicating with the chamber 24. More than one flow passage 26 may be provided. Furthermore, the flow passage 26 could be formed in the collar 20.

The collar 20 defines an internal tapering wedge surface 28 having a profile substantially matching the profile of the outer surface of the end section 14 of the tube or shaft 12.

To secure the connection arrangement to the end of the shaft or tube 12, the wedge member 14 is located within the end section 14 of the tube or shaft 12, the collar 20 is located around the exterior of the end section 14, and the fitting 10 is secured to the wedge member 16. In this condition, a resin material is supplied, under pressure, to the chamber 24 via the passage 26. The pressure with which the resin material is supplied applies a load to the flange 18 and the collar 20 urging these components away from one another. As a consequence, the wedge surface 28 of the collar 20 is urged towards the wedge member 16, clamping the tapering end section 14 of the tube or shaft 12 therebetween.

The fit between the flange 18 and the collar 20 is such that minimal resin material escapes therebetween in use. Escaping resin material may serve to seal the flange 18 and collar 20 to one another preventing or restricting further escape of material.

With the resin material still maintained under pressure, the resin material is cured or allowed to cure or set, forming a resin material element substantially filling the chamber 24, the resin material element serving to maintain the clamping load applied between the collar 20 and the wedge member 14 to secure the fitting 10 to the shaft 12.

It will be appreciated that the arrangement described hereinbefore is advantageous in that the clamping load is not dependent upon screws or bolts, and so the risk of the clamping load reducing over time, for example as a result of screws or bolts working loose, is reduced. The invention thus provides a reliable connection between the fitting 10 and the shaft 12, allowing tensile or compressive loads to be transmitted therebetween. The clamping load can be set conveniently by appreciated control over the resin material injection pressure.

If desired, rather than rely upon, or solely upon, the resin injection pressure to apply the clamping load prior to curing or setting of the resin material, an externally applied load may be used to urge the collar 20 towards the wedge member. Upon curing or setting of the resin material, it will be appreciated that the externally applied load may be removed and the clamping load maintained by way of the presence of the resin material filling or substantially filling the annular chamber 24. In this arrangement, the clamping load can be controlled by appropriate control over the externally applied load.

Although specific embodiments of the invention are described hereinbefore, it will be appreciated that a wide range of modifications and alterations may be made thereto without departing from the scope of the invention as defined by the appended claims.