EP4781094A1 - A fastener and a tool for operation thereof - Google Patents

Abstract

A fastener has a first axial end and a second axial end for attaching a first object to a second object. The fastener comprises a shank and a cylindrical sleeve. The shank has a first end and a second end, and has a first portion and a second portion. The first portion extends from the first end of the fastener and of the shank and is provided with a thread in a first direction, a second portion adjacent the first portion, and a third portion adjacent the second portion. The third portion extends to a second end of the shank and is provided with a thread in a second direction. A cylindrical sleeve extends to the second end of the fastener, and has an outer surface provided with a thread in the first direction and an inner surface provided with a thread in the second direction. The sleeve is removably attachable to the third portion of the shank by threaded engagement of the sleeve inner surface thread with the shank third portion thread to cover the second end of the shank. The shank is rotatable in a first rotational direction to threadedly engage the first portion of the shank in the second object and to threadedly engage the sleeve attached to the second end of the shank in the first object, and to attach the first object to the second object with an inner surface of the first object adjacent an outer surface of the second object. The shank is rotatable in a second opposite, rotational direction to simultaneously partially threadedly disengage the first portion of the shank from the second object and to partially threadedly disengage the third portion of the shank from the sleeve. This moves the second portion of the shank away from both the outer surface of the second object and the inner surface of the first object, as a result of the sleeve being threadedly attached to the first object and threadedly attached to the third portion of the shank. This creates a gap between the outer surface of the second object and the inner surface of the first object, whilst maintaining attachment of the first object to the second object.

Description

A FASTENER AND A TOOL FOR OPERATION THEREOF

The present disclosure relates to a fastener for attaching a first object to a second object and a tool for operation of the fastener.

Commonly, when attaching a first object, such as a batten or door/ window framing, to a second object, such as a wall or an opening in a wall, it is desirable to have the batten door/window framing straight and vertical/horizontal. Invariably, however, the surface of the wall to which the batten or door/window framing is attached is not perfectly flat and vertical/horizontal. At present, to attach the batten or door/window framing to the surface of the wall, a tradesperson will place one or more packers of various thickness between one or more portions of the batten or door/window framing and the surface of the wall, putting in and taking out packers until a substantially straight and vertical/horizontal position of the batten or door/window framing is achieved. Only then can the batten or door/window framing be attached to the surface of the wall with fasteners.

A number of prior art systems have been proposed attempting to overcome the need for packers by employing a specialized fastener and tool. Generally, these systems employ a tool for simultaneously coupling to a screw shank of a fastener and a cover of the fastener, the cover being fitted over the top of the screw shank in an axially freely rotatable manner. The screw shank and cover are then screwed together by the tool to threadedly engage the screw shank into a second object and to threadedly engage the cover into a first object, which lies adjacent to the second object. The tool must then be flipped, or a separate tool must be provided, to present a coupling that only couples to the screw shank, whereupon screwing out the screw shank only causes the screw shank to partially disengage from the second object, while the cover, being freely rotatable relative to the screw shank, remains engaged in the first object, thereby causing the first object to move away from the second object to provide a gap therebetween.

However, when a greater number of fasteners need to be installed, such as in larger building projects, the need for the tool to couple to both the screw shank and cover in the installation of every fastener and the need to change or flip the tool midinstallation can prove to be fiddly and time-consuming. Further, the present Inventor is unaware of any system providing a safety feature that prevents the fastener from being inadvertently over screwed from the second object resulting in insufficient grip to hold the first object to the second object.

The present disclosure has arisen from work seeking to provide an improved fastener and tool for operation thereof that addresses one or more of the above deficiencies.

According to a first aspect of this disclosure, there is provided a fastener having a first axial end and a second axial end for attaching a first object to a second object, the fastener comprising: a shank having a first end and a second end, and having a first portion extending from the first end of the fastener and of the shank and provided with a thread in a first direction, a second portion adjacent the first portion, and a third portion adjacent the second portion, the third portion extending to a second end of the shank and being provided with a thread in a second direction; and a cylindrical sleeve extending to the second end of the fastener, and having an outer surface provided with a thread in the first direction and an inner surface provided with a thread in the second direction, the sleeve being removably attachable to the third portion of the shank by threaded engagement of the sleeve inner surface thread with the shank third portion thread to cover the second end of the shank; wherein the shank is rotatable in a first rotational direction to threadedly engage the first portion of the shank in the second object and to threadedly engage the sleeve attached to the second end of the shank in the first object, and to attach the first object to the second object with an inner surface of the first object adjacent an outer surface of the second object; and wherein the shank is rotatable in a second opposite, rotational direction to simultaneously partially threadedly disengage the first portion of the shank from the second object and to partially threadedly disengage the third portion of the shank from the sleeve, thereby moving the second portion of the shank away from both the outer surface of the second object and the inner surface of the first object, as a result of the sleeve being threadedly attached to the first object and threadedly attached to the third portion of the shank, to create a gap between the outer surface of the second object and the inner surface of the first object, whilst maintaining attachment of the first object to the second object.

As will be appreciated, engagement of the fastener into the first and second objects and provision of a gap between the first and second objects may be accomplished by rotation of the shank only. This simplifies the process of coupling a tool to the fastener and eliminates the need for the tool to be removed, changed or flipped mid-installation, thereby providing a more easily operable, time-efficient system.

It will be appreciated that the relative lengths of the first portion of the shank and of the sleeve, as well as their relative diameters may be varied. However, in practical embodiments, the first portion of the shank may typically comprise between two-thirds and three-quarters of the axial length of the shank, and be provided with a right-hand thread suitable for use with the material of the second object. The first portion of the shank may be provided with a thread comprising any of a wood thread, a concrete thread, a machine thread, and/or a plastic thread.

The second portion of the shank may comprise a raised section having a cutter for cutting an increased width of opening in the first object to accommodate the overall increased width of the fastener where the sleeve covers the second end of the shank. The raised section may comprise a hemispherical rim having one or more raised bars serving as the cutter. The raised section may also have raised portions that serve as drivers for the sleeve. The sleeve is suitably provided with a surface engaging the second portion when the sleeve is fully assembled with the third portion to provide drive from the shank to the sleeve when the fastener is inserted into the first and second objects. This surface may comprise a cut-out section at one end of the sleeve that engages raised sections of the second portion of the shank.

The sleeve may have an internal left-hand thread, and the third portion of the shank a corresponding left-hand thread suitable for use with the material of the cylindrical sleeve.

The raised sections of the second portion of the shank also serve to prevent the left-hand thread of the third potion of the shank being over tightened to the sleeve and possibly locking them together, making it difficult to reverse of the third portion of the shank from the sleeve when a gap is required between the first and second objects.

The outer surface of the sleeve may be less than 15 mm in diameter. Fasteners are commonly installed in wood, such as timber, through holes of around 15 mm in diameter and secured to concrete. Having a fastener with a diameter less than that of the hole is advantageous where it is desirable to see the grain of the wood rather than a fastener, as fasteners placed in these holes can then be hidden by overlaying a pellet with a grain matching that of the wood in which the hole has been drilled.

The outer surface of the sleeve may be provided with a right-hand thread suitable for use with the material of the first object. The outer surface of the sleeve may be provided with a thread comprising any of a wood thread, a concrete thread, a machine thread, and/or a plastic thread. Preferably, the thread of the outer surface of the cylindrical sleeve has a thread pitch equal to that of the thread of the first portion of the shank. This provides for both the cylindrical sleeve and the first portion of the shank to move in tandem when rotated in either of the first or second rotational directions.

The sleeve may have a hexagonal or star socket at the second end of the fastener for removal of the fastener as a whole from the attached first and second objects.

According to a second aspect of this disclosure, there is provided a tool for operation of a fastener of the first aspect of this disclosure, the tool comprising: an elongate member with a distal end portion for engagement with a blind socket on one end of a shank of the fastener, and a proximal end portion adapted for coupling to a rotatable drive; and a reversible sleeve having a through opening adapted to key with the distal end portion of the elongate member in two alternative orientations of the reversible sleeve, the reversible sleeve having a first axial side and a second axial side on the opposite side of the reversible sleeve from the first axial side; the first axial side of the reversible sleeve presenting a profile adapted to be received in a socket provided in one end of a sleeve of the fastener covering the said one end of the shank, the fastener sleeve having an opening through its socket, through which the extreme distal end of the elongate member may pass into engagement with the blind socket; and the second axial side of the reversible sleeve presenting a surface which cannot engage with the fastener sleeve.

The second axial side of the reversible tool sleeve may serve as a safety limiter for the fastener, ensuring that the fastener cannot be reversed to such an extent that the shank separates from the sleeve or from the second object, ensuring instead a secure attachment between the sleeve and the shank.

Reference may now be made, by way of example only, to the accompanying drawings, in which:

Figure 1 is a perspective view of a fastener in accordance with a first aspect of this disclosure;

Figure 2 is a similar view to Figure 1 taken from a slightly elevated perspective;

Figure 3 is a side elevation view of the fastener shown in Figures 1 and 2;

Figure 4 is a cross-sectional view of the fastener taken along the line B-B in Figure 3;

Figure 5 is a perspective view showing a shank and a cover of the fastener shown in Figures 1 to 4 positioned side by side;

Figure 6 is a side elevation view of the shank of the fastener shown in Figures 1 to 5;

Figure 7 is a cross-sectional view of the shank taken along the line D-D in Figure 6;

Figure 8 is an underneath view of the sleeve shown in Figures 1 to 5;

Figure 9 is a front elevation view of the shank shown in Figures 6 to 8;

Figure 10 is a side elevation view of the sleeve of the fastener shown in Figures Figure 11 is a cross-sectional view of the sleeve taken along the line E-E in Figure 10;

Figure 12 is a plan view of the sleeve shown in Figures 10 and 11 ;

Figure 13 is a front elevation view of the sleeve shown in Figures 10 to 12;

Figure 14 is a side elevation view of a tool in accordance with a second aspect of this disclosure showing a reversible sleeve received by an elongate member of the tool in an operative orientation;

Figure 15 is a perspective view of the tool shown in Figure 14 showing the reversible sleeve received by the elongate member in an inoperative orientation;

Figure 16 is a perspective view of the tool as shown in Figure 14;

Figure 17 is a side elevation view of the tool as shown in Figure 15;

Figure 18 is a cross-sectional view taken along the line F-F in Figure 17;

Figure 19 is a plan view of the tool as shown in Figures 15, 17 and 18;

Figure 20 is a similar view to Figure 17 showing the tool without the reversible sleeve;

Figure 21 is a cross-sectional view of the tool taken along the line G-G in Figure 20;

Figure 22 is a plan view of the tool as shown in Figures 20 and 21;

Figure 23 is a side elevation view of the reversible sleeve shown in Figures 14 to 19;

Figure 24 is a cross-sectional view of the reversible sleeve taken along the line H-H in Figure 23; and

Figure 25 is a plan view of the reversible sleeve as shown in Figures 23 and 24.

Referring first to Figures 1 to 5, a fastener 1 for attaching a first object (not shown) to a second object (not shown) has a shank 2 at a first end of the fastener 1 and a generally cylindrical sleeve 3 covering a second end of the shank 2 at the second end of the fastener. The shank 2, as best shown in Figures 5 to 9, has a first portion 4, a second portion 5 and a third portion 6.

The first portion 4 extends from first end 7 of the fastener 1 and is provided with a thread 8 in a first direction, which, in this embodiment, is a right-hand direction. The thread 8 of the first portion 4 is cut to match a type of material of the second object to be attached to the first object by the fastener 1 . The thread 8 comprises, for example, any of a wood thread, a concrete thread, a machine thread, and/or a plastic thread, depending on the material of the second object to be attached to the first object by the fastener 1. The first portion 4 suitably comprises between two-thirds and three- quarters of the axial length of the shank 2, although this could be more or less, as required.

The second portion 5 of the shank 2 is adjacent the first portion 4, as shown. The second portion 5 comprises a raised section in the form of a hemispherical rim 9 whose rounded side faces towards the first end 7 of the fastener 1. Four raised bars 10 are formed as part of the rounded side of hemispherical rim 9 directed generally towards the first end 7 of the fastener 1 and are spaced equally around the circumference of the rim 9. Raised bars 10 serve as a cutter for providing an increased width of opening in the first object to accommodate the increased width of the sleeve 3 as compared with the shank 2.

The third portion 6 of the shank 2 is adjacent the second portion 5, as shown. The third portion 6 of the shank 2 extends to a second end 11 of the shank 2 adjacent the second end of the fastener and is provided with a thread 12 in a second direction, which, in this embodiment, is a left-hand direction. The thread 12 of the third portion 6 is cut to match the type of material of the cylindrical cover 3 of the fastener 2. The second end 11 of the shank 2 is provided with a blind socket 13 in the form of a hexagonal or star-shaped socket adapted for coupling with a tool for operation of the fastener 1. As will be readily appreciated, any suitably shaped socket that can cooperate with the cross-section of an appropriate cooperating tool may be employed. In the illustrated embodiment, blind socket 13 is star-shaped.

Referring now to Figures 10 to 13, the cylindrical sleeve 3 has an outer surface 14 provided with a thread 15 in the first (right-hand) direction, extending from one end 16 of the sleeve 3, which is provided with a socket 17 for receipt of a tool for turning the sleeve 3. The thread 15 can be interrupted at regular intervals all around, as in conventional Type BF cutting screws, to improve engagement of the cover 3 into the first object. The thread 15 of the outer surface 14 is cut to match the type of material of the first object to be attached to the second object by the fastener 1. The thread 15 on the outer surface 14 comprises, for example, any of a wood thread, a concrete thread, a machine thread, and/or a plastic thread, depending on the material of the first object to be attached to the second object by the fastener 1. The thread 15 of the outer surface 14 of the sleeve 3 has a thread pitch equal to that of the thread 8 of the first portion 4 of the shank 2, thereby providing for both the sleeve 3 and the first portion 4 of the shank 2 to move in tandem when screwed in either of the first or second rotational directions. The socket 17 formed in the end 16 of the sleeve 3 may take any convenient form such as a hexagonal socket or a star-shaped socket depending on the corresponding shape of the tool with which it is intended to cooperate. In the illustrated embodiment, socket 17 is star-shaped. Socket 17 must have a cross-sectional shape greater than that of blind socket 13 in the end of shank 2, and its centre 18 must be open so that a cooperating tool can extend through that open centre to couple with blind socket 13.

The cylindrical sleeve 3 has an inner surface 19 which is provided with a thread 20 in the second (left-hand) direction. The sleeve 3 is removably attachable to the third portion 6 of the shank 2 by engagement, or screwing, of the thread 20 of the inner surface 19 of the sleeve 3 with the thread 12 of the third portion 6 of the shank 2. The sleeve 3 is further provided with two stops 21 each formed from a diagonal cut-out section taken from a second end 22 of the cover 3. The third portion 6 of the shank 2 is provided with two raised sections 23, corresponding to the two stops 21 , that rest adjacent the rim 9 of the second portion 2. The stops 21 and raised sections 23 are designed for engagement. When the sleeve 3 is screwed onto the shank 2 by way of threads 12, 20 as described above, the sleeve 3 draws closer to the second portion 5 until each stop 21 reaches and engages each corresponding raised section 23. Thus, when the shank 2 is rotated in a first rotational direction, in this embodiment, a clockwise rotational direction, the sleeve 3 is caused to engage with the shank 2 and the sleeve 3 is prevented from threadedly disengaging from the third portion 6 of the shank 2. The stops 21 being formed from diagonal cut-out sections of sleeve 3 permit this action when the shank 2 is rotated in the first rotational direction only; the diagonal gradient provided by the diagonal cut-out sections causes the sleeve 3 to slide over raised sections 23 and disengages from the shank 2 when the shank 2 is rotated in a second rotational direction, in this embodiment, an anticlockwise direction.

Thus, sleeve 3 is removably attached to the second end of shank 2, as seen in Figures 1 to 4.

In use, when the shank 2 of the fastener 1 is rotated in the first (clockwise) rotational direction, the first portion 4 of the shank 2 is threadedly engaged, or screwed, into the second object (not shown), and the second portion 5 and the third portion 6 of the shank 2 and the sleeve 3 attached to the third portion 6 are threadedly engaged, or screwed, into the first object (not shown). The first object is attached to the second object with an inner surface of the first object adjacent an outer surface of the second object.

When the shank 2 of the fastener 1 is rotated in the second (anticlockwise) rotational direction, the first portion 4 of the shank 2 partially threadedly disengages from the second object and the sleeve 3 partially threadedly disengages from the third portion 6 of the shank 2. This moves the second portion 5 and third portion 6 of the shank 2, the sleeve 3 attached to the third portion 6 and the first object threadedly engaged with the sleeve 3, away from the second object. Since the sleeve 3 is engaged with the first object, this pulls the first object away from the second object and this provides a gap between the inner surface of the first object and the outer surface of the second object, whilst maintaining attachment of the first object to the second object. This enables the first object to be attached to the second object but remain in a substantially straight and vertical/horizontal attitude, without the need for packers between the first object and the second object. Moreover, since the sleeve 3 is threadedly attached to the third portion 6 of the shank 2, the gap can be provided by rotation of the shank 2 only, so that a tool for operation of the fastener 1 is not required to have a coupling for engaging the sleeve 3. Removal of the fastener 1 as a whole from the first and second objects will still require a tool to have a coupling for engaging the sleeve 3, however. The outer surface 14 of the sleeve 3 has a diameter of less than 15 mm, which, in this embodiment, is 14 mm. Thus, after fastener 1 is fixed, for example, through a hole of 15 mm in a timber wall, the fastener 1 in the hole can be hidden by overlaying a pellet with a grain matching that of the timber wall to provide a more aesthetic finish.

Referring now to Figures 14 to 25, a tool 24 for operation of the fastener is illustrated. It is provided with a bit 25 hexagonal cross-sectioned in its proximal end portion 26 in conventional fashion for receipt in a chuck of a drill or rotatable screwdriver adapted to receive alternative bits for other purposes. Distal end portion 27 of the bit 25 has a cross-section corresponding to, but slightly smaller than the cross- sectional shape of the blind socket 13 in the second end 11 of the shank 2.

Tool 24 also carries a reversible sleeve 28. As best shown in Figure 20, intermediate its hexagonal cross-sectioned proximal end portion 26 and its star-shaped smaller cross-sectioned distal end portion 27 is a smoothly cylindrical cross-sectioned land 29 smaller in cross-section than the distal portion 27. Sleeve 28 has an opening 30 therethrough of cross-section slightly larger than that of the distal portion 27, so that sleeve 28 can be slid along the distal portion 27 until it reaches the land 29, where it is freely rotatable, and from where it can be slid no further along bit 25, the hexagonal-cross-sectioned proximal portion 26 being of too great a cross-section. In the orientation shown in Figure 16, sleeve 28 may be slid back down distal portion 27, with which it is keyed for rotation, to engage a star-shaped profile portion 31 of tool sleeve 28 with socket 17 of sleeve 3 of the fastener, while the extreme distal end of distal portion 27 may pass through open centre 18 of socket 17 to engage with blind socket 13 of the shank 2. When the tool sleeve 28 is reversed, as shown in Figure 15, sleeve 28 may still be slid back down star-shaped cross sectioned distal portion 27, but presents a flat annular surface 32 to the fastener which cannot engage with it, only the extreme distal end of distal portion 27 passing through centre 18 of socket 17 being able to engage with blind socket 13 on end 16 of shank 2.

The fastener 1 may be operated by the tool 24 to attach a first object comprising a batten to a second object comprising a wall. A hole is first drilled in and through the batten and in the wall.

With the batten placed against the wall, and sleeve 28 of the tool 24 in the orientation of Figure 15, and the proximal end of the tool bit received in the chuck of a drill or rotatable screw-driver, the bit 25 is rotated in a clockwise sense to screw the fastener 1 forwardly through the batten and the first end 7 of the shank 2 into the wall with the extreme distal end of distal portion 27 engaged with blind socket 13 on end 11 of shank 2. If necessary, cutter 10 will widen the drilled hole in the batten to accommodate the fastener sleeve 3. A drill bit with a double cutting action (not shown) may initially be used to form a wider hole in the batten for accommodating the fastener sleeve 3.

The first portion 4 of the shank 2 is thus threadedly screwed, into the wall and the fastener sleeve 3 is screwed, into the batten. The batten is thus attached to the wall with an inner surface of the batten adjacent an outer surface of the wall. When the fastener 1 is substantially fully inserted into the batten, the sleeve 3 will grip the batten and hold it in place against the wall.

When the outer surface of the wall is not flat, attaching the batten to the wall using a number of spaced fasteners 1, with an inner surface of the batten adjacent the outer surface of the wall, may cause the batten to bend to substantially fit the contour of the non-flat outer surface of the wall. This in turn, will distort the batten from being substantially straight and vertical/horizontal, which is undesirable. In this situation, a gap is required between the inner surface of the batten and the outer surface of the wall.

To adjust the batten, with the extreme distal end of distal portion still engaged with blind socket 13, the tool is rotated slightly in the second reverse (anti-clockwise) direction. This causes rotation of the shank 2 in the reverse (anti-clockwise) direction. This causes the first portion 4 of the shank 2 to be slightly screwed out of the wall, and causes the third portion 6 of the shank 2 to simultaneously be slightly screwed out of the sleeve 3, thereby causing sleeve 3 to move away from the wall. Since the sleeve 3 is also threadedly engaged with the batten, it grips the batten so that movement of the sleeve 3 of the fastener 1 away from the wall consequently moves the batten away from the wall. This provides a small gap between the inner surface of the batten and the outer surface of the wall, whilst maintaining attachment of the batten to the wall. By adjusting different fasteners 1 between the batten and the wall, the batten is attached to the wall and kept substantially straight and vertical/horizontal, without the need for packers between the batten and the wall, and without the need for the tool 24 to couple to the sleeve 3 or to change or flip the tool 24 mid-installation.

The fastener 1 may include an indicator, for example, a red line (not shown) on the first portion 4 of the shank 2 extending a preset distance from the first end 7 of the shank 2, signifying to a user that the shank 2 should not be screwed out of the wall beyond that preset distance in order to maintain a secure installation.

Should the fastener 1 as a whole need to be removed from the batten (first object), the reversible tool sleeve 28 is positioned as shown in Figure 16 on the distal portion 27 of the tool 24 so that star-shaped profile portion 31 may engage with socket 17 on fastener sleeve 3 while the extreme distal end of distal portion 27 engages with blind socket 13 on the end 16 of shank 2. Rotation of the tool 24 in the reverse anticlockwise sense will then withdraw the shank 2 and sleeve 3 of fastener 1 together.

Claims

1. A fastener having a first axial end and a second axial end for attaching a first object to a second object, the fastener comprising: a shank having a first end and a second end, and having a first portion extending from the first end of the fastener and of the shank and provided with a thread in a first direction, a second portion adjacent the first portion, and a third portion adjacent the second portion, the third portion extending to a second end of the shank and being provided with a thread in a second direction; and a cylindrical sleeve extending to the second end of the fastener, and having an outer surface provided with a thread in the first direction and an inner surface provided with a thread in the second direction, the sleeve being removably attachable to the third portion of the shank by threaded engagement of the sleeve inner surface thread with the shank third portion thread to cover the second end of the shank; wherein the shank is rotatable in a first rotational direction to threadedly engage the first portion of the shank in the second object and to threadedly engage the sleeve attached to the second end of the shank in the first object, and to attach the first object to the second object with an inner surface of the first object adjacent an outer surface of the second object; and wherein the shank is rotatable in a second opposite, rotational direction to simultaneously partially threadedly disengage the first portion of the shank from the second object and to partially threadedly disengage the third portion of the shank from the sleeve, thereby moving the second portion of the shank away from both the outer surface of the second object and the inner surface of the first object, as a result of the sleeve being threadedly attached to the first object and threadedly attached to the third portion of the shank, to create a gap between the outer surface of the second object and the inner surface of the first object, whilst maintaining attachment of the first object to the second object.

2. A fastener according to Claim 1, wherein engagement of the fastener into the first and second objects and provision of a gap between the first and second objects may be accomplished by rotation of the shank only.

3. A fastener according to Claim 1 or Claim 2, wherein the first portion of the shank comprises between two-thirds and three-quarters of the axial length of the shank, and is provided with a right-hand thread suitable for use with the material of the second object, namely being a wood thread, a concrete thread, a machine thread, or a plastic thread.

4. A fastener according to any preceding Claim, wherein the second portion of the shank comprises a raised section having a cutter for cutting an increased width of opening in the first object to accommodate the overall increased width of the fastener where the sleeve covers the second end of the shank.

5. A fastener according to Claim 4, wherein the said raised section comprises a hemispherical rim having one or more raised bars serving as the cutter.

6. A fastener according to Claim 4 or Claim 5, wherein the said raised section also has raised portions configured to serve as drivers for the sleeve.

7. A fastener according to any preceding claim, wherein the sleeve is provided with an engagement surface arranged to engage the second portion when the sleeve is fully assembled with the third portion to provide drive from the shank to the sleeve when the fastener is inserted into the first and second objects.

8. A fastener according to Claim 7, wherein the engagement surface comprise a cut-out section at one end of the sleeve that operatively engages raised sections of the second portion of the shank.

9. A fastener according to any preceding claim wherein the sleeve has an internal left-hand thread, and the third portion of the shank a corresponding left-hand thread suitable for use with the material of the cylindrical sleeve.

10. A fastener according to Claim 9, wherein the raised sections of the second portion of the shank also serve to prevent the left-hand thread of the third portion of the shank being over tightened to the sleeve and possibly locking them together, making it difficult to reverse of the third portion of the shank from the sleeve when a gap is required between the first and second objects.

11. A fastener according to any preceding claim, wherein the outer surface of the sleeve is less than 15 mm in diameter, so that the fastener is adapted to be installed in wood through a hole of 15 mm in diameter and secured to concrete so that the fastener placed in such a hole may be hidden by overlaying a pellet with a grain matching that of the wood in which the hole has been drilled.

12. A fastener according to any preceding claim, wherein the outer surface of the sleeve is provided with a right-hand thread suitable for use with the material of the first object and the thread of the outer surface of the cylindrical sleeve has a thread pitch equal to that of the thread of the first portion of the shank, whereby both the cylindrical sleeve and the first portion of the shank may move in tandem when rotated in either of the first or second rotational directions.

13. A fastener according to any preceding claim, wherein the sleeve has a hexagonal or star socket at the second end of the fastener for removal of the fastener as a whole from the attached first and second objects.

15. A tool for operation of a fastener according to Claim 1 , the tool comprising: an elongate member with a distal end portion for engagement with a blind socket on one end of a shank of the fastener, and a proximal end portion adapted for coupling to a rotatable drive; and a reversible sleeve having a through opening adapted to key with the distal end portion of the elongate member in two alternative orientations of the reversible sleeve, the reversible sleeve having a first axial side and a second axial side on the opposite side of the reversible sleeve from the first axial side; the first axial side of the reversible sleeve presenting a profile adapted to be received in a socket provided in one end of a sleeve of the fastener covering the said one end of the shank, the fastener sleeve having an opening through its socket, through which the extreme distal end of the elongate member may pass into engagement with the blind socket; and the second axial side of the reversible sleeve presenting a surface which cannot engage with the fastener sleeve.

16. A tool according to Claim 15, wherein the second axial side of the reversible tool sleeve is capable of serving as a safety limiter for the fastener, ensuring that the fastener cannot be reversed to such an extent that the shank separates from the sleeve or from the second object, ensuring instead a secure attachment between the sleeve and the shank.