AU769505B2 - A fastener - Google Patents

Description

1 A FASTENER FIELD OF THE INVENTION This invention is directed to a fastener, and particularly to a fastener which has an expanding body portion which forms part of the fastening action.

BACKGROUND ART There are various different types of fastening devices available in the marketplace. One type of fastening device is a nail which is hammered into a workpiece. The nail fastens by displacing the workpiece material as the nail is driven into the workpiece. The workpiece material then compresses around the nail to keep the nail in place. Another type of fastening device is a screw. The screw works by forming a helical pathway into the workpiece.

The main disadvantage with a nail or a screw is that these fasteners are not suitable to fasten thin sheets together. This is because the fasteners are required to penetrate into the workpiece by a considerable amount in order to grip the workpiece. Moreover, a nail only functions in a workpiece which is formed of a material which can compress around the nail.

Thus, a nail does not work in metal and plastic. A screw can function in metal and plastic but when relatively thin workpieces are fastened together, the screw will not secure the workpieces together very firmly.

Expandable bolts and anchors are known. These are often used in brick and masonry. One known type of expandable bolt requires a hole to be predrilled into the substrate, and the bolt is then hammered into the hole S-such that it is fairly tightly secured. A nut is then rotated on the bolt which causes a part of the bolt body to expand to lock the bolt into the substrate.

A similar mechanism is available for use with plasterboard walls.

This type of bolt is usually made of plastics or light gauge steel. A hole is predrilled into the plasterboard wall and the bolt is inserted through the hole.

A part of the bolt is then rotated by a screwdriver to cause the bolt to expand and lock behind the plasterboard wall.

Rivets are known and have particular use for fastening thin sheets of material together. Thus, thin sheets of metal can be riveted together. The riveting operation is quite clumsy in that it is necessary to 2 initially pre-drill a hole through the sheets of metal. The rivet is then attached to the rivet gun and pushed through the hole. The rivet gun is then operated (which is a two-handed operation) to expand the rivet head and to snap off the stem of the rivet. The operation is particularly intensive and it is quite difficult to rivet two pieces of metal together in difficult to access positions. As an example, a riveting operation is difficult and quite hazardous when standing on a ladder as the riveting operation is a two-handed operation.

Also known is a fastener comprising a hollow outer sleeve without internal threading, an internal member with a tip capable of drilling holes which is externally threaded and a wedge-shaped member, movement of the wedgeshaped member causing expansion of the hollow outer sleeve. This fastener does not possess any means to prevent rotation of the hollow outer sleeve once inserted into the hole. It is also a three part fastener which is complex and therefore increases cost of manufacture. It is also difficult to use onehanded.

Another known fastener is one which comprises a hollow rivet casing with an internal thread, formed with predetermined breaking grooves extending parallel to an axis of the casing and a stop flange to provide a mount, and a rivet spindle with an external thread, terminating in a drill bit. This fastener lacks means for preventing rotation of the hollow rivet casing. Its use involves breaking the hollow casing and as such requires more force to be applied to .the driving means to force the breakage.

Yet another known type of fastener comprises a hollow elongate tube with a flange, having an internal threaded section with a second section without internal threads, of larger diameter than the threaded section, a threaded shank having a portion adapted to be gripped by the jaws of a chuck and a drill bit, and a plastics material filling the space between the enlarged portion of the tube and the shank. This fastener is quite complex to manufacture, S• requiring the plastic material to be inserted into the enlarged section. The 30 plastic material may also harden with age and cease to function as it was intended. The complexity of manufacture leads to a more expensive fastener.

Still another known type of fastener comprises a hollow elongate portion with an enlarged head having a permanently deformable tubular extension with 3 internal threads, and a shank with external threads. This fastener also has locking or stopping means to prevent twisting of the hollow portion. The shank has a means extending beyond the head of the elongated, hollow portion for applying torque to the shank which is provided with a weakened section in order to induce fracture of the extension. The extension of the shank is a problem as it makes the fastener larger than necessary and also may, given the required force, be fractured prior to fixing in the required position thus rendering the fastener useless.

OBJECT OF THE INVENTION It is an object of the invention to provide a fastener which has an expandable portion to allow it to fasten materials together, and where the fastener is easy-to-use and in most cases is a single-handed operation requiring only one tool.

In one form, the invention resides in a fastener, the fastener having an outer body and an inner portion, the outer body and the inner portion being attached to each other, the inner portion being adapted for rotation by an external tool, the outer body having a stop means to prevent rotation of the outer body when the fastener is inserted into a workpiece, the construction and arrangement being such that the external tool can rotate the inner portion which causes rotation of the outer portion as the fastener is inserted into the workpiece, but when the stop means engages with the .workpiece, the outer body is prevented from further rotation which causes the outer body and the inner portion to separate such that further rotation of the inner portion causes the inner portion to retract through the outer portion causing an expansion of the outer body.

0 **0In another form, the invention resides in a fastener comprising an outer body and an inner portion, the outer body and the inner portion being attached to each other, the outer body having a stop means to prevent rotation of the S• outer body when the fastener is inserted into a workpiece and having an 30 opening to allow an external tool to engage a tool engaging part of the inner portion, the inner portion being adapted for rotation by the external tool, the construction and arrangement being such that the external tool can rotate the inner portion which causes rotation of the outer portion as the fastener is 4 inserted into the workpiece, but when the stop means engages with the workpiece, the outer body is prevented from further rotation which causes the outer body and the inner portion to separate such that further rotation of the inner portion causes the inner portion to retract through the outer portion causing an expansion of the outer body.

One advantage of these fasteners is that they can be used in a single-handed operation. For instance, in an embodiment, the external tool can be a cordless drill which has a drill bit or like member which engages with the inner portion. This can hold the fastener onto the cordless drill. The fastener can be inserted into the sheets of material which are to be fastened together, when the stop means engages with the material, the outer body is prevented from rotation. Actuation of the cordless drill then causes the inner portion to rotate back through the outer body which causes the outer body to expand or swell to lock the two pieces together. It is possible for the fastener to be provided with a forward drill bit. This allows the fastener to drill the hole through the material and pre drilling is therefore not required. As the fastener passes through the material, the stop means will engage with the material which will then prevent the outer body from further rotation and begin the process of the inner portion passing through the outer body thereby swelling the outer body to lock the two pieces together.

•The outer body is typically cylindrical and substantially hollow and may comprise a sleeve or tube of material. The outer body can be formed of any suitable material including plastics, metal, composite materials and the like. The material should be such to allow the outer body to swell or deform. It is also envisaged that the outer body can be caused to split. The length of the outer body can vary to suit. It is envisaged that fasteners of different lengths will be provided depending on the thickness of the material which is to be fastened. The diameter or cross-section of the outer body can vary to suit. Larger diameter fasteners may be used when a more secure fixing is required. Larger diameter fasteners may also be required if the 0: material is rather fragile or frangible and where the material may fracture around the fastener if the fastener is too small.

The fastener may be self drilling. In this version, the fastener may be provided with a leading or forward cutting portion. If a cutting portion is provided, it is preferred that the cutting portion has a cross-section portion which is larger than the internal cross-section or diameter of the outer body such that retraction of the cutting portion through the outer body will cause the outer body to swell or become enlarged.

Alternatively, the fastener may not be self drilling and therefore does not have a forward cutting portion. In this alternative, the fastener may be provided with a forward part which has a larger cross-section portion than the internal cross-section or diameter of the outer body such that retraction of this forward part through the outer body will cause the outer body to swell, or become enlarged. The forward part may have various shapes sizes and configurations. It is envisaged however that the forward part will have a tapered or pointed leading portion to facilitate insertion of the fastener into the hole in the workpiece.

The fastener has an inner portion. The inner portion is secured to the outer body such that rotation of the inner portion will cause rotation of the outer body as long as the stop means does not prevent rotation of the outer body. The inner portion may be frictionally secured to the outer body.

Alternatively, the inner portion may be secured to the outer body by means of a frangible or breakable portion.

The inner portion is adapted for rotation by an external tool. In oo* one form, the inner portion can be provided with a tool engaging part which may comprise a socket, a slot (to engage a screwdriver tool), a cross arrangement (to engage a philips head type screwdriver), or any other type of 25 tool engaging means. Typically, a socket is provided which may be a square socket, a rectangular socket, a polygonal socket and the like to engage with a correspondingly shaped tool. The tool is typically attached to a cordless drill 0• and can be rotated upon operation of the drill.

The tool engaging part in the inner portion is preferably somewhat towards the front of the fastener such that the tool passes somewhat through the fastener. This allows the fastener to be attached to the a.

tool in such a manner that it will not easily fall off. This facilitates attachment of the fastener to the work material. Additional gripping means to grip the tool 6 may be provided on the fastener to ensure that the fastener is held onto the tool and does not inadvertently fall off.

The inner portion may be formed with a threaded part. The threaded part may frictionally engage with the outer body to frictionally hold the inner portion against the outer body. The threaded part preferably has a turn such that when the outer body is prevented from further rotation, further rotation of the inner portion will now cause the threaded part to pass up through the inner portion.

The inner portion is typically attached to a front part which extends in front of the outer body. The front part may comprise a cutting bit, although this is not essential. The front part may function to cause expansion of the outer body as the inner part is pulled back through the outer body by the tool. Thus, it is preferred that the front part has a portion which is larger than the internal diameter or cross-section of the outer body such that the front part will force deformation, splitting or swelling of the outer body as the front part is pulled through the outer body.

The stop means functions to prevent or resist rotation of the outer body when the fastener has been inserted into the workpiece. The stop means may comprise projections or extensions from the outer body which can engage with or bite into the workpiece. For instance, the outer body may be provided with claws to bite into the workpiece. Alternatively, the outer body may be provided with a tapered portion which jams the outer body into the workpiece.

A cap may be provided. The cap typically extends over a rear part of the outer body. The cap may be provided with an opening through "which the tool can pass. The opening may be dimensioned to lightly grip against the tool to hold the fastener to the tool.

BRIEF DESCRIPTION OF THE DRAWINGS ~Embodiments of the invention will be described with reference to the following drawings in which: Figure 1 is a part section view of a fastener.

Figure 2 is the view of the fastener of Figure 1 in the expanding position.

Figure 3A-3D are plan views of various different shaped fasteners.

Figures 4A-C are side views of various different shaped outer bodies Figure 5 illustrates a fastener having a forward drill bit.

Figures 6A-D illustrate various stop members on the outer body.

Figure 7 illustrates a typical tool and the some tip shapes.

BEST MODE Referring initially to Figure 1 and Figure 2 there is illustrated a fastener 10. The fastener 10 has a cylindrical outer body 11, an inner portion 12, and an annular stop means 13. Cylindrical outer body 11 can have various lengths which can be from 10mm to 50mm. This can of course vary to suit. The diameter of the cylindrical outer body can be between and this can also vary to suit. Cylindrical outer body 11 may be formed from thin metal or plastic material and should be made of a material which can bulge or deform or split. Cylindrical outer body 11 has a front end 14 and a rear end 15. The rear end 15 is covered by a cap 16 which may be formed integrally with the outer body. Cap 16 has a central aperture 17 to allow a tool to pass into the fastener 10. Aperture 17 may be dimensioned to engage with the outer wall of the tool to allow the tool and the fastener to be lightly attached together. Front end 14 is open.

Stop means 13 are provided. In figure 1, stop means 13 is an annular collar around the outer body 11 and abutting against the bottom wall S:of cap 16. The annular collar tapers outwardly. Thus, as the fastener is pushed into a hole or drills its own hole, once the fastener has been inserted fully into the hole, the annular collar 13 will bite into the workpiece to prevent any further rotation of outer body 11. Figure 2 illustrates a stop means in the form of teeth or claws 14. Figures 6A-D illustrate various other types of stop means in the form of tapered or expanding portions underneath cap 16 which wedge the fastener into the hole.

Inner portion 12 has a forward part 18 which extends in front of front end 14 of outer body 11. In figure 1, forward part 18 is a drill bit. This means that the fastener can drill its own hole through the work material. The 8 drill bit is tapered and has a wider most portion 19 which has a width which is slightly larger than the outer diameter of outer body 11. This means that as the fastener is drilled into the workpiece, the drill bit drills a hole which is only slightly larger than the diameter of outer body 11. The wider most portion 19 has a width which is less than the outer most width of stop means 13. This means that when the fastener is fully inserted into the hole, the outer body 11 will become wedged in the hole due to the stop means 13 frictionally engaging with the wall of the hole.

Attached to forward part 18 is a rear part in the form of a helical thread 19. Helical thread 19 sits inside outer body 11. The outer most diameter of helical thread 19 is such that it frictionally engages with the internal wall of outer body 11. The frictional engagement is sufficient to ensure that rotation of the inner portion will also cause rotation of the outer body. Inner portion 12 is provided with a tool engaging means 20. In the embodiment, this is in the form of a socket 21 which can engage with a tool having a corresponding shape. Figures 3A-D illustrate various socket configurations. Helical thread 19 is a left-hand thread which means that the thread will engage with the inside wall of outer body 11 and will ride up outer body 11 if allowed to do so.

In use, the fastener is initially as illustrated in Figure 1. A tool 22 (see Figure 7) has a forward portion 23 which passes through aperture 17 in cap 16 of the fastener and into socket 21. The fastener is then lightly held to tool 22. Tool 22 can be fitted to a drill chuck. The fastener is then pressed up against a workpiece (not illustrated). Rotation of the drill (not illustrated) will cause rotation of tool 22 which in turn will rotate inner portion 12 and therefore the entire fastener as the inner portion and the outer body 11 are held together by frictional engagement between helical thread 19 and the inner wall of outer body 11. Cutting bit 18 then drills into the workpiece to cut a hole which is just large enough to allow the outer body 11 to pass into the hole. At this stage, the outer body is rotating with the inner portion. Upon further insertion of the fastener into the hole, the stop means 13 will grip against the inner wall of the hole and will prevent further rotation of the outer body. At this stage, the torque on inner portion 12 increases to the point that a helical 9 thread 19 will begin to rotate relative to outer body 11. Helical thread will then begin to travel up the inside of outer body 11. As a helical thread 19 is attached to cutting bit 18, the cutting bit is also pulled into outer body 11.

Cutting bit 18 has a portion 19 which is a wider than the inner diameter of outer body 11 which means that as the cutting bit is pulled through the outer body, it will cause the outer body to bulge or swell, or even to split apart. The outcome is that the fastener becomes locked into the hole thereby locking the fastener to the workpiece.

Ribs 24 can be provided which extend longitudinally along the inside wall of outer body 11. The ribs function to provide a controlled splitting or fracturing of the outer body, as the inner portion is pulled through the outer body.

Figure 2 illustrates the locked position where cutting bit 18 has been slightly retracted into outer body 11 and has cause the outer body to split.

Figures 4 illustrate various cap designs 16 to provide a countersunk arrangement, a domed arrangement and a flush arrangement respectively.

Figure 5 illustrates a fastener with a particular type of cutting bit.

The cutting bit may be suitable for cutting through soft material such as wood S" or plastic, hard material such as metal, or material such as masonry and brick.

Figures 6 illustrate various different types of stop means to lock the outer body against rotation when the fastener is inserted into the material.

:The fastener has great versatility in fastening materials together.

Typically, the fastener can be used in a single-handed operation. All that is required is to fit the fastener to the end of the cordless drill and to drill the fastener into the material. Initially, the fastener will drill into the material and after the stop means engages with the material, the inner portion will begin to move up to lock the fastener to the material. There are no pieces left over which need to be removed, which is a problem with rivets where the stem of the rivet is snapped off and needs to be removed. The fastener can be 0 @9 designed such that once locked to the material, the inner part of the fastener can function to hold other parts such as hooks and the like. The inner part may be subsequently filled with adhesive or other suitable material to function as a chemical lock. Thus, the fastener can be used to fastener separate materials to each other but can also be used as a wall anchor to allow other parts or articles to be attached to the fastener once the fastener has been locked to the material.

It is not essential that the fastener has a cutting bit. For instance, if the material has a preformed hole, the fastener can be simply inserted into the hole. The cutting bit can then be replaced by a non cutting forward part which upon retraction will cause the outer wall to bulge split etc.

The fastener can be used on metal, plastic, timber, concrete, fibreglass and the like.

It should be appreciated that various other changes and modifications may be made to the embodiment described without departing from the spirit and scope of the invention.

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Claims (25)

1. A fastener comprising an outer body and an inner portion, the outer body having a stop means to prevent rotation of the outer body when the fastener is inserted into a workpiece, an internally threaded tubular body portion with a lower end and an opening to allow an external tool to engage a tool engaging part of the inner portion, wherein the tool engaging part comprises a tool opening, the inner portion having an externally threaded outer surface, the inner portion provided with a forward part which has a larger cross-section portion than the internal cross-section or diameter of the outer body such that retraction of this forward part through the outer body will cause the outer body to swell, or become enlarged, the inner portion being adapted for rotation by the external tool, the outer body and the inner portion being frictionally secured to each other at least at the lower end of the outer body, the construction and arrangement being such that the external tool can rotate the inner portion which causes rotation of the outer portion as the fastener is inserted into the workpiece, but when the stop means engages with the workpiece, the outer body is prevented from further rotation which causes the outer body and the inner portion to separate such that further rotation of the inner portion causes the inner portion to retract through the outer portion causing an expansion of the outer body. :o The fastener as claimed in claim 1, wherein the outer body is cylindrical.

3. The fastener as claimed in claim 1 or 2, wherein the outer body is substantially hollow.

4. The fastener as claimed in any one of the preceding claims, wherein the outer body can be caused to split. The fastener as claimed in any one of the preceding claims, wherein the fastener is self drilling.

6. The fastener as claimed in any one of the preceding claims, wherein the 30 fastener is provided with a leading or forward cutting portion.

7. The fastener as claimed in claim 6, wherein the cutting portion has a cross-section portion which is larger than the internal cross-section or diameter of the outer body such that retraction of the cutting portion through the outer body will cause the outer body to swell or become enlarged.

8. The fastener as claimed in either one of claims 6or 7, wherein the forward part has a tapered or pointed leading portion to facilitate insertion of the fastener into the hole in the workpiece.

9. The fastener as claimed in any one of claims 1-8, wherein the inner portion is secured to the outer body by means of a frangible or breakable portion. fastener as claimed in any one of the preceding claims, wherein the tool engaging part comprises a socket.

11.The fastener as claimed in claim 9, wherein the tool engaging part comprises a slot for instance, to engage a screwdriver tool.

12.The fastener as claimed in claim 9, wherein the tool engaging part comprises a cross arrangement for instance, to engage a philips head type screwdriver.

13.The fastener as claimed in claim 10, wherein the socket is a square socket.

14.The fastener as claimed in claim 10, wherein the socket is a rectangular socket.

15. The fastener as claimed in claim 12, wherein the socket is a polygonal socket.

16.The fastener as claimed in any one of the preceding claims, wherein the external tool is attached to a cordless drill and can be rotated upon operation of the drill.

17.The fastener as claimed in any one of the preceding claims, wherein the tool engaging part in the inner portion is adjacent the front of the fastener such that the tool passes somewhat through the fastener.

18.The fastener as claimed in any one of the preceding claims, wherein additional gripping means to grip the tool is provided on the fastener to ooooo ensure that the fastener is held onto the tool and does not inadvertently fall off.

19.The fastener as claimed in any one of the preceding claims, wherein the inner portion is formed with a threaded part. 13 The fastener as claimed in claim 19, wherein the threaded part frictionally engages with the outer body to frictionally hold the inner portion against the outer body.

21.The fastener as claimed in claim 19 or 20, wherein the threaded part preferably has a turn such that when the outer body is prevented from further rotation, further rotation of the inner portion will cause the threaded part to pass up through the inner portion.

22.The fastener as claimed in any one of the preceding claims, wherein the inner portion is attached to a front part which extends in front of the outer body, wherein the front part has a portion which is larger than the internal diameter or cross-section of the outer body such that the front part will force deformation, splitting or swelling of the outer body as the front part is pulled through the outer body.

23.The fastener as claimed in claim 19, wherein the front part comprises a cutting bit.

24.The fastener as claimed in any one of the preceding claims wherein the stop means functions to prevent or resist rotation of the outer body when the fastener has been inserted into the workpiece. fastener as claimed in any one of the preceding claims, wherein the 20 stop means comprises projections or extensions from the outer body which can engage with or bite into the workpiece.

26.The fastener as claimed in any one of the preceding claims, wherein the outer body is provided with claws to bite into the workpiece.

27.The fastener as claimed in any one of the preceding claims, wherein the outer body is provided with a tapered portion which jams the outer body into the workpiece.

28.The fastener as claimed in any one of the preceding claims, further comprising a cap extending over an exposed part of the outer body.

29.The fastener as claimed in claim 25, wherein the cap is provided with an opening through which the external tool can pass. fastener as claimed in claim 26, wherein the opening is dimensioned lightly grip against the external tool to hold the fastener to the external tool. 14

31.A fastener substantially as described with reference to the attached drawings. Dated this 20th day of November 2003 Vincent James Lowcock By his Patent Attorneys CULLEN CO.