This invention relates to a fixing for insertion into a wall, particularly, but not exclusively, hollow walls and the like i.e. those having an outer substrate and a void or space behind the substrate.

Fixings for hollow walls and the like, such as so-called stud walls, sheet- rock walls, dry lined walls, hollow doors, and other sheet material constructions generally use two parts - a plug and a screw. Known plugs are pushed into a predrilled hole and a screw is inserted into the plug. Some known plugs are self drilling and use a large coarse thread to hold the plug in place in the wall, while others have elements that expand into the void or space behind the outer substrate, for example, when the screw is inserted.

These known fixings require at least two separate procedures or stages for fixing an item to the wall. For example drilling, inserting the plug, and inserting the screw. Where a batten, cupboard or the like needs to be fixed to the wall, there is a further stage of drilling a hole in the baton etc.

The inventors have realised that a fixing which allows just one procedure to fix an item to the wall is needed.

According to a first aspect of the invention there is provided a fixing for attaching items to a hollow wall or the like having a substrate in front of a void, the fixing including a threaded bolt rotatable about a fixing axis, the bolt having a head at a proximal end of the fixing and a substrate piercing part at a distal end of the fixing for forming an aperture through the substrate at least into the void when said - bolt is forced into the substrate and/or rotated, the fixing further including an anchor sleeve mounted or mountable on the bolt, said sleeve having an outer diameter and overlaying at least a portion of the bolt and having a collar adjacent the proximal end of the fixing extending radially outwardly beyond said outer diameter, and having a portion adjacent the distal end of the fixing including a thread complementary with the thread of the bolt, said anchor sleeve having an initial unexpanded position and a final expanded position in which one or more arms of the anchor are forced radially outwardly, characterised in that said arms include one or more first elements expandable into the substrate and one or more second elements expandable into the void, and in that the first element(s) is(are) closer to the head than the second element(s).

In this way a fixing is provided which has no obstacles when it is rotated or otherwise forced into the substrate in its initial position, so the anchor sleeve can move with the bolt e.g. rotate, but which has first element(s) which are forced outwardly expand to grip the substrate and second element(s) which expand into the void to stop the fixing being pulled out of the aperture.

In an embodiment the outer diameter of the anchor sleeve is generally constant along its length, in an initial position.

In an embodiment, the bolt includes a shank portion adjacent the head which is of increased diameter and which is cooperable with said one or more first elements to force the element(s) radiailly outwardly when the increased diameter shank portion of the bolt enters the aperture.

It is envisaged that the piercing part will produce an aperture which will accommodate the anchor sleeve so that said sleeve can rotate with the bolt in the aperture when the sleeve is in the initial unexpanded position. In the initial position during insertion, the head and collar are spaced and the bolt and sleeve may rotate together in the aperture. In an alternative insertion technique, the sleeve may be held stationary for a short time. When the fixing is increasingly inserted into the aperture, the collar finally abuts an outer surface of the substrate. As the bolt continues into the wall the bolt moves axially relative to the sleeve, which may be axially stationary, and the increased diameter shank portion of the bolt moves to expand the first element(s) to grip the substrate. Thus the sleeve is then inhibited or prevented from further rotation. Further rotation of the bolt, with the sleeve axially and rotationally stationary in the aperture, causes the threaded portion of the sleeve to move along the axis toward the proximal end, forcing the second element(s) radially outwardly into the void and thus preventing the fixing from being pulled out of the aperture.

Preferably the anchor sleeve is manufactured from a single plastics moulding.

Preferably the single piece moulding includes a tubular formation having said threaded portion at one end and said collar at the other end, and axial closed-end slits defining said second element(s), and further slits defining said first element(s).

Preferably said second elements have weakened areas which bend under axial compression of the anchor sleeve.

Alternatively the anchor sleeve is formed from a plurality of discrete components.

Said discrete components may include one or more of: an inner deformable piece which includes the arms; an outer slotted sleeve having one or more axially extending slots, said slots coinciding with said first and second element(s) of said arms, allowing said element(s) to be forced radially outwardly through said slots; a nut having wings which are slideable within the slots but not rotatable relative to the outer sleeve, said nut including the complementary thread for axially compressing said inner piece and causing said forcing of said element(s) as the bolt is rotated relative to the nut.

Preferably, the bolt is manufactured from metal and the anchor sleeve or one or more components of the anchor sleeve is formed from plastics material.

Preferably said first and second elements each include a pair of elements diametrically opposed on either side of the axis.

Preferably the piercing part is a helically fluted drill formation.

According to a second aspect of the invention there is provided a fixing for attaching items to a wall or the like having a substrate in front of a void, the fixing including a threaded bolt rotatable about a fixing axis, the bolt having a head at a proximal end of the fixing and a substrate piercing part at a distal end of the fixing for forming an aperture through the substrate at least into the hollow when said bolt is forced into the substrate and/or rotated, the fixing further including an anchor, mounted or mountable on the bolt and overlaying at least a portion the bolt, and having a portion at the distal end including a thread complementary with the thread of the bolt, said anchor having one or more arms which are resiliently radially outwardly biased, and said arms being held in a radially inward position in a retainer, said retainer being axially moveable on the bolt to release the arms. In an embodiment the retainer includes a collar at the proximal end extending radially outwardly further than the remainder of the retainer.

In use the collar is caused to abut an article to be held to an outer surface of the substrate while the bolt is forced further into the wall. Thus the collar will move to the proximal end and release the arms in use.

Preferably the retainer holds the anchor loosely to allow enough relative axial movement to release the arms but little or no relative rotation about the axis.

Preferably, features of the first aspect mentioned above may be incorporated into the invention according to the second aspect.

According to a third aspect, the invention extends to a fixing for attaching items to a wall or the like, the fixing including an anchor sleeve having a fixing axis and an outer diameter, said sleeve accepting a threaded bolt in use by means of turning the bolt in a portion of the sleeve which has a complementary thread or a portion of the sleeve which is complementarily threadable, said sleeve having an initial unexpanded position and a final expanded position in which one or more gripping arms of the anchor sleeve are forced radially outwardly of the axis, by the action of sleeve accepting the bolt.

A fixing according to the third aspect may have features of the fixing according to the first or second aspects.

The invention extends to any novel feature, or any novel combination of features described herein.

The invention can be put into effect in numerous ways, non-limiting examples only being described below with reference to the drawings wherein: Figure 1a shows a sectional view of a fixing according to a first embodiment, in an initial configuration;

Figure 1b shows a section on plane BB in Figure 1a;

Figure 1c shows a section on plane CC in Figure 1a;

Figure 2 shows a sectional view of the fixing in Figure 1 in an initially inserted position in a hollow wall;

Figures 3 and 4 show a sectional view of the first embodiment in transitional positions in use;

Figure 5 shows the first embodiment in a final position;

Figure 6 shows an exploded perspective view of a second embodiment of a fixing;

Figures 7 to 10 show a third embodiment of a fixing in various positions in use.

Referring to Figure 1 , there is shown a sectional view of a fixing 10. The fixing 10 comprises a central threaded bolt 20 having at a proximal end a head

22 including a recess 24 for accepting a screw driver head or the like (not shown) for rotating the bolt about its axis A. At a distal end of the bolt 20 a piercing part 26 is rigidly connected to the bolt 20. In this case the piercing part comprises a short helically fluted drill stub. In use, rotation of the bolt head 22 using a screwdriver bit or the like, causes the drill stub 26 to rotate also. The drill stub is of a sufficient diameter to produce an aperture which allows the remainder of the fixing to slide in that aperture. The bolt 20 includes also an outwardly tapering shank portion 28, adjacent the head, the purpose of which is described below. The fixing 10 further comprises an anchor sleeve 30, which in this embodiment is a plastics moulding fitted around the bolt 20. The anchor sleeve includes a threaded portion 32 adjacent the distal end the fixing 10, first elements, in the form of aperture gripping elements 36, and second elements in the form of a pair of anchor arms 34. The anchor sleeve further includes a collar

38 which is of a larger diameter than the remainder of the sleeve 30 and a washer 40 which is a snug sliding fit over the arms 34 which will prevent spelling in use and will be described in more detail below. A anti-rotation tab 39 is removeably attached to the collar 38. The tab 39 can be held in use to restrain rotation of the sleeve 30.

Figure 1b shows a section on B-B in Figure 1. In this view the arms 34 can be seen more clearly as two diametrically opposed sections on either side of the bolt 20 held together by the washer 40.

Figure 1c shows a section on C-C in Figure 1a and the arrangements of the gripping elements 36 can be seen more clearly. In this case, the gripping elements 36 are connected at one end only with the anchor sleeve 30, but are allowed to cantilever in radial in slots 37 so they can move radially outwardly relative to the axis A.

Figure 2 shows the fixing 10 inserted into an aperture AP in substrate S. The fixing 10 has been rotated about axis A and drill 26 has bored the aperture

AP into the substrate S. Whilst this boring has taken place, the anchor sleeve 30 has rotated with the remainder of the fixing 10. In this instance, the collar 38 captivates a bracket BR for fixing to the substrate S. It will be noted that the washer 40 has moved position. The washer 40 has slid along the sleeve 30 as the fixing 10 has been inserted in the aperture AP. In doing so the washer has prevented the arms 34 from moving radially outwardly while the arms are not in the aperture AP. The gripping elements are located within the circumference of sleeve 30, so they do not act.

Figure 3 shows the result of further drilling and pushing in the direction of arrow F. In this case, the collar 38 now tightly abuts the bracket BR and the head 22 is forced against the collar 38 to close the gap G, shown in Figure 2, between the collar 38 and the head 22. The outwardly tapering shank 28 is now pushed into the aperture AP, which forces the gripping elements 36 radially outwardly from the axis A. The gripping elements 36 are forced into the substrate S causing restraint of the rotation of the anchor sleeve 30 relative to the continuing rotation of the bolt 20, as illustrated.

Figure 4 is an illustration of the action of the anchor sleeve 30 when rotation of the bolt 20 is continued. The threaded portion 32 is moved axially in the direction of arrow E to cause the arms 34 to bow radially outwardly and bend at lines of weakness 35. The tab 39 can be held, for example by a users thumb, if necessary, should the sleeve 30 start to rotate in the aperture AP.

Continued rotation of the bolt 20 causes the arms 34 to abut the rear surface R of the substrate S as shown in Figure 5. In this illustration it can be seen that the bracket BR is securely held to the substrate S, because the washer 40 has, in this case, been forced into the front face F of the substrate.

The fixing of the bracket BR has been carried out in one stage, i.e. the continual rotation of the bolt head 22 without the need for pre-drilling or the fitting of more than one part (like a plug and a screw). In practise, an electric screwdriver can be used to rotate the head 22 with the fixing offered up to the wall already passed through the bracket BR, or other item to be secured to the wall, and then the item can be fixed to the wall in one stage.

Figure 6 shows an exploded view of a second embodiment of a fixing 110 which is similar in construction to the first embodiment and where like parts have like reference numerals prefixed with the numeral 1. In this instance the anchor sleeve 130 is assembled from 4 parts. The anchor sleeve 130 includes an inner plastics moulding 131 which comprises gripping elements 136 and radially expandable arms 134. In addition the anchor sleeve includes a rigid tube 133 which includes 2 diametrically opposed slots 135 for accepting the arms 134 and for accepting the gripping elements 136 in use. The anchor sleeve 130 includes also a nut 132 which has wings 137 slideable in the slots 135 in use.

The operation of the fixing 110 is similar to the operation of the fixing 10. Rotation of the bolt head 122 causes rotation of a piercing part 126 which produces an aperture for the fixing 110 in a substrate. A tapered section 128 of the bolt 120 causes expansion of the gripping elements 136 as the bolt enters the anchor sleeve 130 fully. Further rotation of the bolt 120 relative to the now static anchor sleeve 130 causes the nut 132 to slide in the slots 136 toward the head 122. This action compresses the plastics moulding 131 and causes the arms 134 to expand radially outwardly in a manner similar to the action of the arms 34 shown in Figures 4 and 5. In this instance the arms 134 pass through the slots 135 in the rigid tube 133.

Thus the second embodiment too provides a one stage fixing. In this embodiment a collar 138 is provided which is removable from the anchor sleeve 130 so that an item fixed to a substrate can be removed by detaching the collar 138 from the tube 133.

Figure 7a shows a section through a third embodiment of the invention. Fixing 210 is, again, a one stage fixing. A bolt 220 has a rotatable head 222 and a piercing end 226. In addition, the fixing 210 includes a two part anchor sleeve

230. The anchor sleeve includes an inner portion 231 and an outer portion 233. The inner portion 231 includes fixing arms 234 having retaining lugs 237 and a threaded portion 232. The outer portion includes a retaining barrel 233 and a collar 238.

Figure 7b is a section on plane B-B in Figure 7a. This view shows the retaining barrel 233 and an aperture 235 for retaining the fixing arms 234 and preventing relative rotation between the arms 234 and the retaining barrel 233.

Figure 8 shows the fixing 210 inserted into a substrate S. In this case the head 222 has been rotated using a screwdriver bit or the like and the piercing end 226 has formed an aperture in the substrate S large enough to accept the retaining barrel 233. The retaining barrel 233 has been forced into the aperture but is prevented from rotation by gripping projections 236 illustrated in Figure 7b. The collar 238 now abuts, in this instance, a bracket BR.

Further force in the direction of arrow F causes the fixing arms 234 to be pushed out from the aperture 235 as shown in Figure 9, so that they spring outwardly. Retaining lugs 237 prevent the complete withdrawal of the arms 234 from the aperture 235.

Continued rotation of the bolt 220 against the collar 238 causes the threaded portion 232 to move in the direction of arrow E in Figure 10. This action causes the arms 234 to splay outwardly and engage the rear face R of the substrate S.

This third embodiment too provides a one stage fixing for fixing the bracket BR or the like.

Figures 11 , 12 and 13 show a fourth embodiment of the invention. A side view of a fixing 310 is illustrated in Figure 11 having an arrangement similar in construction to the fixing 10 described above. The fixing 310 includes a threaded bolt 320 having an axis A extending along its length, at proximal end a head 322, and at a distal end a piercing tip 326. The bolt, although slender, is strong enough to be forced through plasterboard and the like using a rotating drill. The bolt includes also an enlarged shank region 328 which has a larger diameter than the remaining shank. In Figure 11 the fixing is shown in its initial position as it would be when the fixing is first used, with the enlarged shank 328 exposed by a distance G. The fixing further includes an anchor sleeve 330, which in this case is a plastics moulding.

The sleeve 330 has a threaded portion 332, a collar 338 which extends radially from the remainder of the sleeve, and a centre portion which is bifurcated to form two folding, and thereby expandable, arms 334, which function in a similar manner to the arms 34 illustrated in Figure 4 and described above. The sleeve further includes radially expandable grippers 336 which move radially outwardly when the enlarged shank portion 328 moves from its expose position into the sleeve 320. A thumb tab 339 is employed in the same manner as the thumb tabs described above.

Figure 12 shows an axial section of the fixing. An insert 333 is used in the plasties moulding 330 having a thread complementary to the thread of the bolt 320. The axial extent of the thread 321 approximately half way along the axial length of the bolt 320 is visible in this drawing.

Figure 13 shows an enlarged view of the anchor sleeve 330. In this view the insert 333, which is preferably formed from metal or a fibre filled polyamide or similar tough plastics, is visible in the end piece 332. The arms 334 have a weakened area 335 at which they will fold under compression when the bolt head is threaded into the sleeve in use and the head reaches the collar 338 after expanding the grippers 336, to expand in the direction of arrows E. Grippers 336 are, in this case formed by slots in the sleeve extending parallel to the axis of the fixing.

Operation of the fixing is similar to the operation of the fixing illustrated in Figures 1 to 5. No washer 40 is used because the arms 334 are strong enough to withstand the forces exerted on them prior to their expansion. Thumb tab 339 can be removed after use if needed, although that is not essential.

Although various embodiments in the invention have been described and illustrated, various modifications, variants, additions or omissions will be apparent to the skilled addressee, falling within the scope of the invention. For example, although the fixings can be used in a single stage, it would be possible to use them for example in a pre-drilled hole where needed, or they could be hammered into place initially to the point where rotation of the bolt 20/120/220/320 is required to expand the related fixing arms. Additionally, although the fixing has been illustrated for use in a hollow wall or the like, they could be used with equal effect in a wall or the like which has no void or where the void is perhaps filled with soft material, for example, insulating material. Where there is no void or the void is filled with material, then the fixings may not expand in the manner illustrated, although even partial expansion of the fixing against the material in which it is inserted will hold the fixing in place.

The preferred material for the bolt is steel because the bolt needs to transmit drilling torque and it will be in tensioned in use. However, other materials such as fibre filled plastics could be used, particularly orientated strand fibre filled plastics. The preferred material for the anchor sleeves is plastics, but again other materials could be used, for example, ductile metals such as soft steel or iron, aluminium or copper could be employed with equal effect. Where the sleeve is made from metal, then the respective collar 38/338 may be removable from the remainder of the sleeve so that whatever is fixed to the wall can be removed without pulling the whole fixing from the wall. Plastics collars have the advantage that they can be bent to remove the item attached to the wall without pulling the sleeve out of the wall.

Various shapes and profiles have been illustrated and described, but it will be readily apparent that other shapes and configurations could be employed within the scope of the invention. For example, the dimensions of the various features could be adapted to suit the fixing of thick battens, or where a narrow void is present, then a shorter bolt could be employed.

In addition the terminology used is intended to embrace equivalents. For example the word bolt is intended to encompass a screw or other elongate part.

The retaining barrel 233 includes a narrowed neck 240 in Figure 7a. This narrowed neck allows the bracket BR to be adjusted to a greater degree than would otherwise be the case. Thus, invention extends to a fixing including a bolt having a piercing tip and an anchor sleeve having a general cross sectional width, the anchor sleeve having a collar adjacent the head of the bolt greater in width than the remainder of the sleeve, and a neck approaching the collar which is reduced in size compared to the cross sectional width.

The thumb tab 39 and 339 shown in Figures 1 , 4 and 11 to 13, could be replaced by a snap-on or removable tool which has the same function of restraining rotation of the collar and sleeve.

The piercing ends shown could be a simple spade-end type flat metal piece, or the fluted drill bit shown. Additionally flattened faces on a pointed end as shown in Figure 6 could be employed.

The washer 40 is shown as a separate part, but could be integrally moulded with the sleeve 30, having a frangible area between the two.

Form more strength, the generally cup shaped (in section) arms 34 and 134 may be extended so that in section they overlap and thereby support each other in bending.

The thread on bolt 20 and 320 may be missing from the distal end of the shank where the complementary part of the thread of the sleeve 30/330 is positioned initially, so that only on insertion of the fixing do the threads of the bolt and sleeve engage. If the bolt is rotated when it is first forced into the substrate, then this will not compress the sleeve because the threads will not yet have engaged.