FIXING

Abstract: A fixing having an elongated body which is provided with two opposite ends and a bore (4) extending into it from one end to receive a fixing member, like a screw. The other end of the body is tapered inwardly to a leading end of the body is tapered inwardly to a leading end of the body (2) to an extent allowing the fixture to be driven into a wall of building material. The other end is further provided with an non-uniform taper of: (a) between 12 DEG to 18 DEG to the longitudinal axis of the body (2) at the leading end; and (b) from 4 DEG to 8 DEG to the longitudinal axis of the body (2) at a portion remote from the leading end.

Description: "Fixing" This invention relates to a fixing. Traditionally, fixings have been used for securing items to walls, the fixing providing a resilient lining for a bore in the wall, into which a screw is driven to secure an item to the wall. The bore has generally been pre-drilled and the fixing then pushed into it. Fixings have been proposed which are hammered directly into the wall without the need for pre-drilling, and this can provide a more convenient means of securing an item to the wall. However, when used in plasterboard or other friable substrate such hammer-in fixings can have the effect of disintegrating the substrate at its far side, thereby reducing the depth of effective contact between the fixture and the wall. It has been proposed to provide a hammer-in fixing having a tapered leading end, and such a product has reduced the extent of disintegration of the substrate. However, the taper is at a shallow angle with the result that the fixing is of considerable length, and this can cause it to interfere with cables and other items beyond the far side of the wall. According to the present invention there is provided a fixing having an elongate body which has two opposite ends, a longitudinal axis and a bore extending into it from one end to receive a fixing member, the other end of the body tapering inwardly to a leading end of the body to an extent allowing the fixture to be driven into a wall of building material, the said other end of the body having an non-uniform taper of (a) between 12° to 18° to the longitudinal axis of the body at the leading end and (b) from 4° to 8° to the longitudinal axis of the body at a portion remote from the leading end. Preferably, the other end of the body is an angularly truncated tube, said truncation defining said non- uniform taper. Preferably also, the mouth of the bore at said one end has a lateral surface extending outwardly around it to limit the extent of penetration of the fixing into the wall. The surface also provides means for spreading the load of a hammer or other driving tool when applied to the fixing. It is further preferable for the bore to be provided with an internal partition wall which close said bore and seperates it into two distinct portions. The partition wall is made of a material (like plastic) which can be ruptured by the introduction of a screw inside the bore. Such partition wall prevents that, when the fixing is positionned into the wall, disintegrated material from the wall enter the bore. The bore may be circular is cross-section, but may advantageously be non-circular, for example oval. Anti-rotation fins may be provided at intervals around said one end of the body projecting externaly from the body so that rotation of a fixing member in the form of a screw into the bore does not result in rotation of the fixing in the wall. At least one aperture, for example slots, may be provided through the side wall of said one end of the body to allow effective radial expansion of that portion of the fixing. The aperture preferably extend along the body and generally parallel to the longitudinal axis . It is also preferred that such slots extend along the body to the depth of the wall of building material. Further according to the invention there is provided a fixing having an elongate body which has two opposite ends, a longitudinal axis and a bore extending into it from one end to receive a fixing member, the other end of the body having a non-uniform longitudinally recessed portion which tapers inwardly to a leading end of the body to an extent allowing the fixture to be driven into a wall of building material, the said other end being flexible to the extent that the non- uniformity of the recessed portion causes it to deflect outwardly from the longitudinal axis of the body on insertion into said wall. Further according to the invention there is provided a hole-forming tool having an elongate body which has a longitudinal axis and that tapers inwardly to a leading end to an extent allowing it to be driven into a wall of material, the taper being (a) between 12° and 18° to the longitudinal axis of the body at its leading end and (b) from 4° to 8° to the longitudinal axis of the body at a portion remote from the leading end. Preferably the said other end of the body is an angularly truncated tube, and said other end defines a longitudinally-extending recess which has a non-uniform taper towards the leading end. Preferably the non- uniform taper has a first portion adjacent the leading end of from 12° to 18°, and a second portion remote from the leading end of from 4° to 8°, measured from the longitudinal axis of the body. An embodiment of this invention will now be described by way of example with reference to the accompanying drawing in which: Fig. 1 is a front view of a fixing of this invention; Fig. 2 is a side view of the fixing of Fig. 1; Figs . 3 and 4 are respectively top and bottom views of the fixing of Fig. 1; and Fig. 5 is a side view of a hole-forming tool of this invention. As shown in Figs 1 and 2 the fixing of this embodiment of the invention has a generally cylindrical body indicated at 2 of glass-reinforced nylon and formed with a bore 4 extending partially along it from one end 6. The upper portion of the bore 4A is wider than a lower portion 4B. The bore 4 is oval in section as shown in Fig. 3 and its opening is surrounded by a circular surface 8 which provides a limit-stop to penetration of the fixing into building material, as well as providing a striking surface for a hammer or the like. Below the surface 8 are four radially outwardly-extending fins 10 equally spaced around the body for resisting rotation of the fixing once installed in building material. Towards said one end 6 are two diametrically-opposed longitudinally-directed slots 12 (see Fig.2) which extend from the end of the fins 10 to a distance of around 13mm from the surface 8. Level with the end of the slots 12 is a recess 14 in the body provided by omission of a part of its wall to provide a scalloped effect. The side edges of the recess 14 provide a taper of around 6° along the body with reference to its longitudinal axis, commencing adjacent the lower extremity of the fins 10 and terminating about 10mm from the lower, or leading end of the body, towards which the side edges of the recess 14 then taper at an angle of 14°. The bore 4 terminates at its lower end just above the upper end of the recess 14, a partition wall or a web 18 of the material extending across the body to prevent entry of detritus from the recess 14 into the bore 4. The fixing is used to secure items such as coat hooks, toilet roll holders, mirrors and the like to walls and may be inserted into solid material such as aerated blockwork or into friable material such as plasterboard. The fixture is driven into the wall by striking the surface 8 with a hammer so that the leading end 16 penetrates the wall until the underside of the surface 8 engages the surface of the wall. When the wall is of solid material the shape of the tapered portions of the body 2 causes the leading end 16 to be forced laterally so that the tapered portions enter the wall along a curved path. This is less noticeable in plasterboard. When the fixing has been fully inserted, a screw is passed through the item to be fixed, into the bore 4. The screw is driven in through the web 18 and until fully inserted. The insertion of the screw causes the portion of the body 2 between the surface 8 and the recess 14 to expand radially outwards against the material of the wall, thereby to provide frictional engagement between the fixing and the wall so as to resist withdrawal; this radial expansion is eased and enhanced by the provision of the slots 12. As the screw is driven into the bore 4 it breaks through the web 18 into the recess 14, and passes straight on. This provides a "forked" arrangement, one prong of the fork consisting of the leading end of the screw and the other prong consisting of the now-curved recessed portion 14 of the body. This forked arrangement further resists withdrawal of the fixing and screw from the wall. A further advantage of this embodiment of the invention is that the 14° taper at the leading end of the body 2 allows the overall length of the body to be kept to a reasonable limit, so as not to penetrate beyond the inner face of a plasterboard wall to an extent that it fouls and interferes with cables and the like in an inter-wall cavity, nor to engage with an inner face of an opposed wall across such a cavity. The 14° taper also provides strength to the leading end of the body which allows it to penetrate aerated blockwork and the like. Referring now to Fig. 5, the hole-forming tool of this embodiment of the invention has a handle 20 from which extends a rigid (for example steel or aluminium) shaft 22 whose general form is the same as the tapered portion of the body 2 of the fixing of Figs 1 to 4 , in respect of its taper angles and the presence of a recess 14 (not shown in Fig. 5). The hole forming tool can be used as an awl for creating a hole through material such as plasterboard and aerated blockwork, where the form of the shaft 22 has similar advantages on insertion to those of the leading end of the body 2 of the fixing of Figs. 1 to 4.

Claims: CLAIMS 1. A fixing having an elongate body which has two opposite ends, said body having a longitudinal axis and a bore extending into it from one end to receive a fixing member, the other end of the body being tapered inwardly to a leading end of the body to an extent allowing the fixture to be driven into a wall of building material, said other end having an non-uniform taper of: (a) between 12° to 18° to the longitudinal axis of the body at the leading end; and (b) from 4° to 8° to the longitudinal axis of the body at a portion remote from the leading end. 2. A fixing as Claimed in Claim 1, wherein said other end of the body is an angularly truncated tube, said truncation defining said non-uniform taper. 3. A fixing as claimed in Claim 1 or 2, wherein the bore is provided with a mouth at said one end which has a lateral surface extending outwardly around it to limit the extent of penetration of the fixing into a wall. 4. A fixing as claimed in any of Claims 1 to 3, wherein a partition wall is provided inside the bore to close said bore and separates it into two distinct portions, said partition wall being made of a material which can be ruptured by the introduction of a screw inside the bore. 5. A fixing as claimed in any of Claims 1 to 4, wherein the bore is oval in cross-section. 6. A fixing as claimed in any of Claims 1 to 5 , wherein anti-rotation fins are provided at intervals around said one end of the body, said fins projecting externally from said body. 7. A fixing as claimed in any of Claims 1 to 6 , wherein at least one aperture is provided through the side wall of the one end of the body. 8. A fixing as claimed in Claim 7, wherein the aperture extends along the body generally parallel to the longitudinal axis of the body. 9. A fixing having an elongate body which has two opposite ends, said body having a longitudinal axis and a bore extending into it from one end to receive a fixing member, the other end of the body having a non- uniform longitudinally recessed portion which tapers inwardly to a leading end of the body to an extent allowing the fixture to be driven into a wall of building material, said other end being flexible to the extent that the non-uniformity of the recessed portion causes it to deflect outwardly from the longitudinal axis of the body on insertion into said wall. 10. A hole-forming tool having an handle attached to an elongated body which has a longitudinal axis, said body tapering inwardly to a leading end to an extent allowing it to be driven into a wall of material, said taper being of: (a) between 12° and 18° to the longitudinal axis of the body at its leading end; and (b) from 4° to 8° to the longitudinal axis of the body at a portion remote from the leading end. 11. A hole-forming tool as claimed in Claim 10, wherein the body is an angularly truncated tube and defines a longitudinally-extending recess which is provided with said taper.

Inventors: WALLACE THOMAS CAMPBELL, WALLACE, THOMAS, CAMPBELL
Applicants: RAWLPLUG CO LTD, WALLACE THOMAS CAMPBELL, THE RAWLPLUG COMPANY LIMITED, WALLACE, THOMAS, CAMPBELL
Application year: 1998
Main classification: F16B13
IPC codes: B25D3, F16B13