In the following, the term"support"will in general be used by convention to mean any item to which a receptacle of a fastener is in use fixed. A support may be for example a cabinet frame or a door frame. Similarly, by convention the term"panel"will in general be used to mean any item that is to be fastened to a support. A panel in general may or may not be planar. A panel may be for example a cabinet or other door. Thus, in general, the terms"panel"and"support"should be taken to include such articles as planar or near-planar sheets (such as vehicle body panels, cabinet doors, etc. ), and non-sheet-like articles (such as cabinet or other door frames, vehicle spare wheels, etc.).

A well known type of releasable fastener is the so- called"quick-acting fastener", which is typically of the so-called quarter-turn type. An example of such a fastener is disclosed in US-A-3169293. This fastener has a hollow cylindrical receptacle, which in this example is fixed to a support by means of an external screw thread on the receptacle, and a stud. The stud has a transverse locking element at one end, such that this end of the stud has a generally T-shape. The T-shape end engages with cam surfaces having locking detents provided at the end of the receptacle. By turning the stud through an appropriate amount, the stud can be locked into and unlocked from the receptacle. A spring is provided between the stud and the

receptacle to bias the stud and receptacle apart. Thus, a panel can be fastened to the support.

A disadvantage of known quick-acting fasteners of these types is that access is required to both sides of the support in which the receptacle is fixed during the fixing process. For example, the receptacle is first inserted from one side of the support so as to protrude through a hole to the other side. Then a welding or other fixing process occurs that requires access to the other side of the support. Finally, the stud is inserted from the first side and, in use, pulls against the weld or other fastening.

Another known device is the so-called blind rivet. A typical blind rivet has a generally hollow cylindrical shape with a radially outwardly protruding flange at one end. A blind rivet typically clamps two members together and is secured to the members by first passing the rivet through holes in the members so as to cause the flange to abut one (outer) side of one of the members. A part of the cylindrical portion is then deformed to provide a second radially outwardly extending flange on one (outer) side of the other member so that the members are trapped between the two flanges and thus clamped together. An insertion tool is used to secure the rivet in this manner. The main advantage of blind rivets is that they can be emplaced from one side only of the members. A blind rivet nut is a blind rivet having a securing means, such as an internal screw thread, to which a stud can be fitted.

An example of a blind rivet is disclosed in EP-A-0656482. The rivet has formations at one end to allow

the rivet to be fixed to a special insertion tool that is used to fix the rivet to a member. In this specific case, the blind rivet of this document is able to receive a fastener stud having a T-shape head which can be locked into opposed axial slots provided by the formations at the end of the rivet. However, the blind rivet of EP-A-0656482 provides for no"pull-up"as the only fixing of the stud to the receptacle is effectively a bayonet-type fitting.

According to a first aspect of the present invention, there is provided a releasable fastener of the quick-acting type, the fastener comprising: a hollow receptacle having a radially outwardly extending flange at one end, a stud- engaging portion at the other end, and a deformable wall portion therebetween, the deformable wall portion being deformable to form a second radially outwardly extending flange such that in use a support can be trapped between the first and second flanges to secure the receptacle to a said support; and, a stud having a shank having a head at one end and a receptacle-engaging portion at the other end for engagement with the stud-engaging portion of the receptacle to lock the stud to the receptacle; the stud- engaging portion of the receptacle and the receptacle- engaging portion of the stud being arranged so as to provide pull-up between the stud and the receptacle when the stud is locked to the receptacle.

The receptacle can be fitted to a support or the like by accessing one side of the support only. This means that the fastener is versatile and can be used in many applications in which traditional quick-acting fasteners cannot be used. Typically, an insertion tool is used to insert the receptacle in the support and to deform the wall

thereby to secure the receptacle to the support. The cooperation between the stud and the receptacle means that there is pull-up, i. e. a high axial clamping load is provided between the support and a panel fastened to the support when the stud is locked to the receptacle.

In a preferred embodiment, the stud-engaging portion of the receptacle is provided by a cam surface and the receptacle-engaging portion of the stud is provided by a radial projection such that rotation of the stud in the receptacle causes the radial projection to ride along the cam surface to draw the stud into the receptacle, thereby to provide pull-up. The cam surface provides a mechanical advantage as the stud is rotated. The cam surface preferably has a detent into which the radial projection of the stud passes when the stud is locked to the receptacle.

In an alternative embodiment, the stud-engaging portion of the receptacle is provided by a wire across the end of the receptacle and the receptacle-engaging portion of the stud is provided by a cam surface such that rotation of the stud in the receptacle causes the wire to ride along the cam surface to draw the stud into the receptacle, thereby to provide pull-up.

In an embodiment, the receptacle is provided internally with a screw thread. The screw thread can be used to mount the receptacle on an appropriately screw- threaded mandrel of an insertion tool during the process of fixing the receptacle to a support. This provides for a more secure mounting of the receptacle on the insertion tool during the fixing process. The screw thread of the receptacle of this embodiment can also be used to allow a

bolt or other screw-threaded stud to be screwed into the receptacle as a fastening element instead of or even in addition to the stud described above.

The fastener may comprise a resilient member for maintaining the clamp force between a said support and a panel fastened to a said support.

According to a second aspect of the present invention, there is provided a receptacle for use with a stud having a shank having a head at one end and a receptacle-engaging portion at the other end, the receptacle being hollow and comprising a radially outwardly extending flange at one end, a stud-engaging portion at the other end, and a deformable wall portion therebetween, the deformable wall portion being deformable to form a second radially outwardly extending flange such that in use a support can be trapped between the first and second flanges to secure the receptacle to a said support, the stud-engaging portion of the receptacle being arranged so as to cooperate with the receptacle-engaging portion of a said stud to provide pull-up between the stud and the receptacle when the stud is locked to the receptacle.

In an embodiment, the receptacle is provided internally with a screw thread.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows an exploded perspective view of an example of a releasable fastener in accordance with an

embodiment of the present invention, showing a receptacle fixed to a support and a panel to be secured to the support by the fastener; Figure 2 shows a perspective view of the receptacle of Figure 1; Figure 3 shows a longitudinal cross-sectional view of the receptacle of Figure 2; Figure 4 shows an end elevation of the receptacle of Figure 2 from one end ; Figure 5 shows an end elevation of the receptacle of Figure 2 from the other end ; Figure 6 shows a side elevation of the stud of Figure 1 ; Figure 7 shows a side elevation of the assembled fastener securing two panels together; and, Figure 8 is a cross-sectional view on VIII-VIII of Figure 7.

Referring to the drawings, a support 1 has a receptacle 2 passing through a through hole 3 in the support 1 and secured to the support 1. A panel 4 has a through hole 5 which may be registered with the hole 3 of the support 1. A stud 6 has a resilient element 7, in this example in the form of a wave spring washer 7, disposed under a head 8 of the stud 6. The stud 6 has an elongate shank 9 of circular cross-section. A crosspiece 10 is

provided at the end of the shank 9 opposite the head 8. In the preferred embodiment, the stud 6 is made of metal and is initially formed with a shank 9 of uniform cross- sectional shape along its length. The crosspiece 10 is formed by stamping either side of the shank 9 at one end, which deforms that end to form the crosspiece 10. As can be seen, in this example the crosspiece 10 is generally of a flat arrow shape.

The receptacle 2 in this example is generally in the form of a cylindrical hollow body of circular cross- section. Other cross-sectional shapes, such as hexagonal, square, etc. , are also possible. The receptacle 2 has a cylindrical side wall 11 with a radially outwardly extending flange 12 at one end. The other end of the receptacle 2 is provided with a stud-engaging portion 13.

In this example, the stud-engaging portion 13 is provided by two substantially identical cam surfaces 14. Each cam surface 14 has a helical cam surface portion 15 which extends for approximately 90° around the end of the receptacle 2. A notch or detent 17 is provided at one end of each helical cam surface 15. The lower part of the wall 11 of the receptacle 2, i. e. that part nearest the stud- engaging portion 13, is relatively thick. Moreover, this part is provided internally with a screw thread 18. The part of the wall 11 of the receptacle 2 closest to the flange 12 is relatively thin.

In a manner known per se in for example the art of blind rivet nuts, the receptacle 2 is secured to the support 1 by deforming the thin part of the wall 11 so as to form a second radially outwardly extending flange 19 and so as to trap the support 1 between the first and second

flanges 12,19. This can be achieved by using an insertion tool of known type, as described generally above. However, in this embodiment, this securing of the receptacle 2 to the support 1 can be facilitated by providing the insertion tool with a screw-threaded mandrel which can be screw fitted to the screw thread 18 of the receptacle 2. This screw threading of the receptacle 2 to the insertion tool provides for a much more secure mounting of the receptacle 2 to the insertion tool than is provided by some prior art arrangements.

The panel 4 is then offered up to the support 1 and the respective holes 3,5 aligned. The crosspiece 10 of the stud 6 is then passed through the hole 5 of the panel 4 into the receptacle 2. As can be seen most clearly in Figures 4 and 5, the interior of the receptacle 2 is shaped to provide a"keyhole"16 so as to allow the crosspiece 10 to pass all the way through the receptacle 2 as required.

In order to clamp the support and panel 1,4 together, the stud 6 is rotated by an appropriate angle, such as between approximately 90° and 130°. This can be facilitated by providing a slot 20 in the head 8 so that the blade of a screwdriver or similar can be inserted, or by other shaping of the head 8. When the stud 6 is rotated, the crosspiece 10 rides up the helical cam surfaces 15 and then drops into the detents 17. Because of the riding up on the helical cam surfaces 15, which provides a mechanical advantage, pull-up is achieved. In other words, an axial clamping load is provided to clamp the support and panel 1,4 together.

Accordingly, the present invention provides a fastener that has the advantages of a blind rivet or blind rivet nut in that it can be secured to a support from one side only.

On the other hand, the fastener also provides for an axial clamping load which is necessary in many applications. The fastener is also of the quick-acting type and can therefore be readily locked and released as required.

As noted above, instead of the crosspiece 10 and the helical cam surfaces 15, etc. on the receptacle 2, a wire may be provided across the end of the receptacle for engagement with cam surfaces on the leading nose of the stud 6 as is known per se.

In addition to the optional use of the internal screw thread 18 of the receptacle 2 for fixing the receptacle 2 to the support 1, the screw thread 18 can receive a bolt or other screw-threaded stud, which may be used in place of or in addition to the stud 6 described above.

Embodiments of the present invention have been described with particular reference to the example illustrated. However, it will be appreciated that variations and modifications may be made to the example described within the scope of the present invention.