AU669986B2 - Improved self-drilling wall anchor - Google Patents

Description

1 BACKGROUND OF INVENTION Field of Invention: This invention relates generally to an anchor which when installed in a hole drilled in a wall is adapted g to receive a threaded fastener that serves to hold a fixture or other object against the wall, and more particularly to a self-drilling anchor of this type which dispenses with the need for any tool other than a screwdriver to install the anchor and which is usable with fasteners of different length.

Status of The Prior Art: In order to mount brackets, fixtures and other objects provided with mounting holes against the outer surface of a wall formed of plasterboard, sheetrock, fiberboard j,/or any other material employed in hollow wall construction, the common practice is to use a hollow anchor for this S purpose. The conventional hollow anchor formed of metal or plastic, when hammered into and wedged within a hole pre-drilled in the wall, is then adapted to receive a e threaded fastener or mounting screw that goes through the mounting hole in the fixture and turns into the hollow of the anchor.

The required length of the mounting screw depends on the thickness of the fixture or object to be supported fagainst the wall. Thus if the object is a thin metal bracket, a screw of smaller length is required than if the object is a thick plate or board, for this dictates a longer screw.

The installation of a conventional anchor entails hree distinct operations, the first and most critical -tep being drilling a hole in the wall, for the diameter f this hole must be appropriate to that of the anchor.

an oversize hole be drilled, then in the next step .nin 'he anchor is hammered into the hole, the anchor <111 not wedge firmly therein but will be somewhat loose.

a consequence, it will not be possible to carry out -e third step.

IC :n the third step, one must turn a threaded fastener :nto the hollow of the anchor, and in doing so tap the 4:chor. But if the anchor is somewhat loose in the wall :ole, this will cause the anchor to turn as the fastener s turned, and the fastener will therefore not be able 1 ~1 thread its way into the anchor.

There is also a possible fourth step that must be S taken into account; for should a need arise to remove an object mounted on the wall or replace it with another object, then one must first unscrew the fastener from 2cthe anchor lodged in the wall. However, if when an unscrewing orque is applied to the fastener, this torque causes the anchor as well as the fastener to turn, then it will S not be possible to withdraw the fastener from the anchor.

The need therefore exists for an anchor which, after being lodged in a hole drilled in the wall, will resist being turned counterclockwise and thereby make it possible to unscrew a threaded fastener from the installed anchor.

3 The installation of a conventional hollow anchor requires three tools: a drill provided with a drill bit having a diameter appropriate to that of the anchor; a hammer to drive the anchor in the hole drilled in the .,wall; and a screwdriver to turn the threaded fastener into the anchor or to later remove it from the anchor.

Though a typical householder or other non-professional possesses a hammer and a screwdriver, ne may lack a drill. But even if he has a drill, he may icnot have a drill bit of the appropriate diameter for the anchor to be installed. Yet there are distinct advantages to be gained by using hollow wall anchors to mount objects against a wall, rather than screws, nails or other fasteners which require no drilling but which have relatively poor lIcholding power, particularly in walls made of friable materials.

Nevertheless, the need for drilling has to a significant degree heretofore discouraged the use of hollow anchors by non-professionals.

Though hollow wall anchors are used on a large scale k-by professional installers, the need to drill holes and then hammer the anchors into holes is a practical drawback, for these operations are time consuming and hence impose distinct limits on the number of anchors that can be installed in a given period. And if anchors of different sizes lmust be installed, then the installer must change the drill bit when switching from one anchor size to another, and this, too, consumes time and reduces the productivity of the installer.

4 To overcome these drawbacks, the 1986 patent to Ernst et al., 4,601,625, discloses an anchor for drywall that has an externally-threaded cylindrical section adapted to receive a fastener, and an unthreaded drilling section.

This anchor is installable using only a hand-powered screwdriver for this purpose, thereby dispensing with the need for a drill and a hammer. At the upper end of the anchor is a low profile flange or head which allows the anchor to be installed flush with the drywall surface.

ic The Ernst et al. patent discloses an embodiment or an anchor molded of zinc, and another embodiment formed of plastic material. Both embodiments include a drill section that can be deflected laterally upon insertion of a mounting screw therethrough. This makes it possible i to use a single mounting screw or fastener of moderate length in conjunction with the anchor for attaching objects o. of various thicknesses to the wall. It is also possible when the need arises to do so, to use longer fasteners.

In Ernst et al., the drill section is formed by k-a single flat blade whose free end is notched to define a central spike and a pair of peripheral spikes on either side of the central spike the function of the central spike, which extends beyond the peripheral spikes and therefore is the first to penetrate the surface of the fdrywall, is to maintain the location of the rotating drill section as a hole is drilled by the peripheral spikes.

In practice, when a single blade is used to bore a hole in friable material such as drywall, the resultant drilled hole may not be perfectly round, for when this material encounters the central or guide spike, it tends to make the blade whip, as a consequence of which the drilling is shifted off center and the bored hole is oversize or elliptical.

Object of the Invention It is the object of the present invention to overcome or substantially ameliorate the above disadvantages.

Summary of the Invention There is disclosed herein a self-drilling anchor installable by means of a screwdriver or similar tool in a hollow wall, said anchor comprising: an externally-threaded shank section provided at its upper end with a head adapted to receive said tool for turning the anchor into the wall, and a longitudinal bore adapted to threadably receive a fastener for holding an object against the outer surface of the wall; and a hollow core drill integral with the shank section, said core drill having at 1least one cutting member whereby as the anchor is turned into the wall by the tool, the cutting member then bores a round hole in the wall and as the anchor continues to turn, the shank section enters and taps the hole until the head engages the outer surface of the wall to complete the anchor installation said hollow core drill having a passage therein communicating with the longitudinal bore in the shank section to permit said fastener to advance from the shank section into the core drill.

There is further disclosed herein a one-piece, self-drilling anchor installable by S. means of a screwdriver or similar tool in a hollow wall, said anchor comprising: a shank section provided at its upper end with an enlarged head adapted to receive said tool for turning the anchor into the wall, said shank section having a root, a spiral cutting thread surrounding the root, and a longitudinal bore adapted to threadably receive and engage a fastener for supporting an object adjacent the wall; and a hollow drill zone integral with the shank section and extending axially therefrom, said drill zone having at least one cutting edge for drilling a round hole in the wall having a circular bank and guide means therefor adapted to engage the bank, whereby as the anchor is turned into the wall by the tool, the cutting edge then bores a round hole in the wall whose bank is engaged by the guide means to ensure circularity of the hole, and as the anchor continues to turn, the shank section enters and taps a matching thread in the bank.

There is further disclosed herein a combination of self-drilling anchor installable in a hollow wall by means of a torque-producing tool and a threaded fastener received in the anchor and engaged thereby, to hold an object adjacent the wall, said anchor comprising: an externally-threaded shank section adapted to receive the tool for turning the anchor into a wall in which the anchor is to be installed, the shank section having a longitudinal bore receiving the threaded fastener and tapped thereby to engage the fastener S holding said object; and holdinig said ebjcct; and drilling means integral with the shank section and extending therefrom for drilling a hole of uniform diameter in the wall in which the anchor is to be installed which is tapped by the shank section to secure the anchor to the wall, said drilling means having a passage therein communicating with the bore in said shank section to permit said fastener received in the shank section to advance therebeyond into said passage.

There is further disclosed herein the combination of a self-drilling anchor installable in a hollow wall by means of a torque-producing tool and a threaded fastener received in the anchor and engaged thereby to hold an object adjacent the wall, said anchor lo comprising: an externally-threaded shank section adapted to receive the tool for turning the anchor into a wall in which the anchor is to be installed, the shank section having a longitudinal bore receiving the threaded fastener and tapped thereby to engage the fastener said object; and drilling means integral with the shank section and extending therefrom for drilling a hole of uniform diameter in the wall in which the anchor is to be installed which is tapped by the shank section to secure the anchor to the wall, said drilling means having a passage therein having a leading portion provided with an opening communicating with the bore in said shank section to permit said fastener received in the shank section to advance therebeyond into said passage.

There is further disclosed herein a self-drilling anchor installable by means of a screwdriver or similar tool in a hollow wall, said anchor comprising: a shank section provided at its upper end with an enlarged head adapted to receive said tool for turning the anchor into the wall, said shank section having a root, a spiral threading surrounding the root, and a longitudinal bore adapted to threadably receive a fastener for holding an object against the outer surface of the wall; and S" a drill section integral with the shank section and extending axially therefrom, said drill section having at least one cutting member and guide means therefor, whereby as the anchor is turned into the wall by the tool, the cutting member then bores a round hole in the wall whose bank is engaged by the guide means to ensure circularity of the hole, and as the anchor continues to turn, the shank section enters and taps the hole until the head engages the outer surface of the wall to complete the anchor installation; wherein said drill section is constituted by a cylindrical core drill having a longitudinal bore that is generally aligned with the bore of the shank section, said drill having a cutting bit, the exterior cylindrical surface functioning as guide means, whereby a fastener threadably received in the bore of the shank section and having a greater length can pass through the bore of the drill section.

There is further disclosed herein a self-drilling anchor installable in a hollow wall FQ by means of a screwdriver or similar tool, said anchor comprising; I:\LIBTTIOO1 an externally-threaded shank section having a longitudinal bore adapted to threadably receive a fastener for holding an object against the wall and provided at its upper end with an enlarged head to receive the tool for turning the anchor into the wall; and a substantially cylindrical core drill section integral with the shank section and extending axially therefrom, said drill section having a longitudinal bore substantially aligned with the bore of the shank section whereby a fastener threadably received in the bore of the shank section and having a greater length can pass into the bore of the drill section, said drill section having a bit defined by at least one cutting tooth, whereby when lo the anchor is pressed into the wall, turning of the tool causes the tooth to drill a hole in the wall whose circularity is ensured by the cylindrical exterior surface of the drill section which acts as guide means, the hole then being entered into by the threaded shank section which taps the hole until the head of the shank section lies against the outer surface of the wall.

Brief Description of the Drawings Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings wherein: r IR,4 IBT)015:M

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Aq Fig. 1 is a perspective view of a self-drilling anchor Fig. 2 is a top view of 'he anchor: Fig. 3 is a magnified rerspective view of the point portion of the drill section of the anchor: Fig. 4 is a transverse section taken through the drill section of the anchor to show the relationship of the cutting blades to the guide blades; Fig. 5 illustrates the anchor installed in a hollow I wall, a threaded fastener being received in the anchor having a length such that it extends the full length of the shank section, but not beyond: Fig. 6 shows the installed anchor with a fastener whose length is such as to split open the drill section; i S Fig. 7 is the same as Fig. 6 except that in this instance, the fastener acts to break off the drill section; Fig. 8 shows the anchor with the same fastener as In Fig. 6 in which it splits open the drill section, this anchor being installed in a double wall; .Fig. 9 is a perspective view of a self-drilling anchor having a core drill section in accordance with the invention; Fig. 10 is an elevational view of the anchor; Fig. 11 is a longitudinal section taken through the anchor; Fig. 12 is a transverse section taken in the plane indicated by line 12-12 in Fig. 11; 'Fig. 13 shows the points of the drill section in relation to the hole to be drilled; and d Fig. 14 shows the anchor installed in a hollow wall, with a threaded fastener being received in the anchor 8 DETAILED DESCRIPTION OF INVENTION The Basic Anchor: Referring now to Figs. 1 to 4, there is illustrated In these figures a self-drillng anchor S'the anchor being molded of synthetic plastic material and having a hollow shank section 10 and a drill section 11ii integral therewith.

The synthetic plastic material from which the anchor is molded must be of high strength, and when formed to C create a sharp edge, this edge must be capable of cutting the material of the hollow wall in which the anchor is installed. The wall is made of plasterboard, sheet rock, fiberboard and any other material used in hollow wall construction. This material is usually friable; that eeooo: is to say, it is easily crumbled, and the anchor for this wall must take this into account.

••el t Preferably, the anchor is molded of nylon reinforced with long glass fibers (about 30% by weight) to provide a composite which is ductile and therefore moldable at e 2 low cost. The fiberglass constituent of the composite affords the strength and rigidity required of the anchor and also effective cutting edges for the drill section.

S In practice, the composite material possesses a natural or neutral color that will blend with the surface color of the hollow wall.

Hollow shank section 10 is adapted to receive an externally-threaded fastener or mounting screw to hold a bracket, a fixture, a board ov any other object having a mounting hole against the surface of the wall in which T z the anchor 4s installed. The length of the fastener is 9 appropriate to the thickness of the object to be held.

Shank section 10 has at its upper end an enlarged head 12 or flange in a low-profile, truncated conical formation. When the anchor is installed in a hollow wall -f plasterboard of other relatively soft material, head 12 will then sink into the wall and lie flush against its surface.

Formed on the underside of head 12 is a radial array of ratchet teeth T whose triangular geometry is such that 4 when the anchor is turned clockwise into a wall and the teeth engage its surface, the teeth slip in this direction and do not impede turning, whereas should one thereafter seek to turn out the anchor, the teeth will bite into the wall to resist counterclockwise movement of the anchor.

)h Because of this feature, should the occasion arise when one wishes to unscrew the threaded fastener from an anchor installed in a wall, this action will not at the same time cause the anchor to unscrew from the wall and thereby render it difficult if not impossible to remove the fastener Sfrom the anchor.

Because the flange or head 15 is formed of composite nylon material having some degree of flexure, the teeth T on the underside of the head will yield and not cut e o away the plasterboard or other wall material as the anchor ,fis being screwed into its final position.

An advantage of an anchor whose head lies flush against the wall in which the anchor is installed, apart from the fact that this head does not slightly space the fixture or other object being mounted from the wall, is that if the fixture is later removed from the wall, and one wishes to erase the presence of the anchor, there is no need to remove the anchor. One has only to spackle over the head to provide a clean wall surface.

Shank section 10 has a longitudinal cavity 13 therein having a cruciform formation defining at 90' intervals ridges R extending the length of the shank section. Ridges R which surround the central zone of the cavity are capable of being tapped by the threading of a metal mounting screw or fastener. One may therefore employ in conjunction with the anchor mounting screws in a limited range of diameters rather than a screw having a predetermined diameter.

And as will later be explained, the mounting screw may be much longer than the length of shank section 10, for the drill section yields to permit the screw to more or jless extend beyond the shank section to accommodate fixtures or other objects of various thicknesses to be mounted against the wall.

The cruciform formation of the cavity creates a socket in head 15 of shank section 10 adapted to receive the blade of a Phillips-type screwdriver or of a conventional screwdriver which is either manually driven or motor powered.

Shank section 10 has a root 14 which is tapered, whereas the convolutions of the spiral threading 15 which surrounds the root have crests that are of essentially the same diameter for the full length of the section except for the final convolution 15F which is of reduced diameter to merge with drill section 11 and thereby avoid an abrupt transition from drill section 11 to shank section 11 The relationship of the threading to the root is such as to cause material which is easily pvlrerized as the shank section is turned into the wall, to form a densified mass surrounding this section to resist withdrawal of the anchor from the wall.

Drill section 11 is provided with a pair of cutting blades 16A and 16B which, as best seen in Fig. 4, extend in opposite directions from the longitudinal axis X of the anchor so that the planar cutting edges E of these blades are diametrically opposed and act to cut a hole H in the wall when the anchor is turned. At right angles to the respective cutting blades is a pair of guide blades 17A and 17B which engage the bank of hole H to ensure circu'arity of the hole bored in the wall whereby axis X of the anchor is colinear lo with the center axis of the hole.

The outer ends O e of the guide blades are convex to conform to the curvature of the bank of the hole and to sweep the bank as the drill section is turned. In this way, a round hole is bored into the wall, thereby avoiding the tendency of a drill section having a single blade as in the Ernst et al. patent, to cut an oversize or elliptical hole.

The lower ends of the cutting and guide blades 16A, 16B and 17A, 17B are chamfered. The lower ends of the cutting blades which are somewhat longer than the guide blades define a triangular point P. Thus when the anchor is pressed into the surface of a wall, point P penetrates into the surface. When the anchor is then turned by a torque-producing tool, a hole is bored therein by the cutting blades as guided by the guide blades to ensure the formation of a round hole.

In practice, the self-drilling anchor shown in Figs. 1 to 4, instead of being made nf synthetic plastic material, may be fabricated of a corrosion-resistant metal such as zinc or brass.

Installation 25 Referring now to Fig. 5, there is shown an anchor installed in a hollow wall whose thickness is less than the length of shank section 10 of the anchor, so that a portion of this section extends beyond the inner surface of the wall. It will be seen that lowprofile head 15 of the anchor lies flush with the outer surface of the wall and that the teeth T on the undersurface of head 15 are embedded in the wall material to resist turning out 30 of the anchor.

Received in the hollow of shank section 10 is a mounting screw 19 which holds a fixture 20 against the surface of the wall, fixture 20 having a mounting hole 2! to admit the screw. The length of mounting screw 19 is such that its tip is received in a conical well 22 at the lower end of the cavity in hollow shank section 10 just above the drill 35 section. In practice, the cavity may be internally-threaded to receive the mounting screw or it may be unthreaded so that as the mounting screw is turned into the cavit;, it taps its way therethrough.

12 Because mounting screw 19 fits into the cavity of the shank section and does not, when fully turned in, go beyond this section, the integrity of .i section 11 is maintained in the arrangement shown in Fig. However, in the anchor installation shown in Fig. 6, use is made of a much longer mounting screw 23 which when turned into shank section 10 forces its way beyond the well at the lower end of the cavity and in doing so splits open drill section 11 to permit the mounting screw e e* A e 13 to exit from the shank section. Since the drill section has already carried out its drilling function, the disruption of the drill section after drilling is performed does not interfere with the installation of the anchor. And .since the split drill section is outside of the wall, It does not affect the holding power of the anchor.

It is to be noted that no notch or indentation is required in the anchor to facilitate the exit of the mounting screw from the shank section, for the tip of the advancing mounting screw enters the conical well in the shank section cavity and then strikes the drill section at its center to effect a splitting action in which the two cutting blades and their associated guide blades assume a V formation.

S. In the anchor shown in Fig. 7, when mounting screw 23 is turned into shank section 10, drill section 11, instead of being split as in Fig. 6, is broken off or laterally displaced from the shank section. To facilitate this action, the anchor need not be provided with annular grooves or notches at the junction of the shank and drill °°o sections, for the natural weakness of this junction causes the drill section to break off when a force is applied °ooo to this junction by the advancing mounting screw, thereby o permitting the mounting screw to exit from the shank section.

S In practice, the strength of the bridge between the cutting .i hiades of the drill section will determine when this section will spit open and triangulate or break off.

In Fig. 8, the anchor is installed in a double wall formed by wall 18 superposed on a wall 18' of the same thickness. Hence in this instance, shank section .whep the anchor is installed, does not extend beyond the hollow wall but is fully embedded therein. As a consequence, 14 when drill section 10 is split open into a V formation, the apex portion of the V is lodged in wall 18' and the wings of the V act as a toggle to resist withdrawal of the anchor from the walls. Thus in a double-wall installation .which is often used in a high quality commercial construction, an anchor in accordance with the invention affords enhanced holding power.

Core Drill Anchor: Referring now to Figs. 9 to 12, there is shown a reusable |p self-drilling anchor in accordance with the invention, generally designated by numeral 24, which may be molded of synthetic plastic material, such as Nylon, or of corrosion-resistant metal, such as zinc. The anchor includes a hollow shank section 25 having at its upper end an enlarged l) head 26 or flange in a low-profile, truncated conical formation. When the anchor is installed in a hollow wall of plasterboard or other relatively soft material, head 26 will then sink into the wall and lie flush against its outer surface.

~2 Formed on the undersurface of head 26 is a radial array of teeth 27, preferably in a triangular ratchet formation, so that when the anchor is turned clockwise into the wall and the teeth then engage its surface, the teeth will slip in this direction and hence not impede )Aiturning. But should one thereafter seek to turn out the anchor, such counterclockwise motion will be resisted by the teeth.

Shank section 25 has a longitudinal bore 28 therein having a cruciform formation defining at 900 intervals ribs or ridges 28R extending the length of the shank section.

Ridges 28R which surround the central zone of bore 28 are capable of being tapped by the threading of a metal mounting screw or fastener. One may therefore employ in conDunction with this anchor, mounting screws in a limited range of diameters rather than a screw having a predetermined diameter.

The cruciform formation of the bore creates a socket in head 26 of shank section 25 adapted to receive the blade of a Phillips-type screwdriver or that of a conventional screwdriver which is either manually driven or motor powered.

Shank section 25 has a root 29 which is tapered, Miwhereas the convolutions of the spiral threading 30 which surrounds the root have crests that are of essentially the same diameter for the full length of the section except for the final convolution, which is of reduced diameter.

As pointed out in connection with the other embodiments of the anchor, the relationship of the threading to the root is such as to cause wall material which is easily pulverized as the shank section is turned into the wall, to form a densified mass surrounding this section to resist withdrawal of the anchor from the wall.

Integral with and extending axially from shank section is a cylindrical core drill section 31 whose external diameter matches the external diameter of the tapered root 29 of the shank section at the lowermost end of this root. Hence the root of the shank ^"ction flows into the drill section without any discontinuity therebetween.

The longitudinal bore 32 of the drill section is aligned with the longitudinal bore 28 of the shank section The diameter of bore 32 is such as to accommodate any mounting screw or threaded fastener capable of tapping the bore 28 of the shank section. As pointed out above, one does not have to employ with this anchor a fastener of predetermined diameter, for it is usable with fasteners Ic in a limited range of diameters, as long as the diameter of the fastener is such that it can pass through the bore without causing the anchor to expand, rupture or deflect.

A conventional core drill is a hollow drill that removes a cylindrical core from the drill hole, the core drill having a cylindrical bit that functions as the cutting element of the drill.

In the core drill section 31 in accordance with the invention, the bit therefor is constituted by a pair of diametrically-opposed cutting teeth T 1 and T 2 Each tooth is defined by a curved wall having a triangular form. The inclined edges of the triangle function as cutting blades and the apex as a sharp spike or point.

Hence when, as shown in Fig. 13, the anchor is pressed into a typical wall of relatively soft material, the points i. P 1 and P 2 of the core drill section penetrate the wall, the points being at the poles of the diameter D of the hole H to be drilled. This diameter is equal to the diameter of the cylindrical core drill section.

17 The cylindrical exterior surface of the core drill section acts as guide means to ensure the circularity of the drilled hole, for as the screwdriver turns the core drill section into the wall material, the bit teeth

T

1 and T 2 proceed to cut a round hole whose form is defined by the cylindrical exterior surface.

After the drill section has drilled a hole in the wall W, as the anchor continues to be turned by the screwdriver, the shank section of the anchor then enters this hole, cand the threading of this section taps the drilled hole, until, as shown in Fig. 14, the head of the shank section engages the surface of the wall.

The length of the self-drilling anchor is determined by the thickness of the hollow wall for which it is intended; I, for when the anchor is being installed, its drill section 31,for most materials should project from the rear of the wall before the threads of the shank section engage and tap the drilled hole. In Fig. 14, the length of the shank section 25 is longer than the thickness of the wall; /C hence a lower portion of the shank section sticks out of the wall.

To hold a fixture 33 against the outer surface of wall W, a threaded fastener 34 is inserted through the mounting hole in the fixture into the bore of the shank section and is screwed therein, the fastener tapping its way into the bore. The length of fastener 34 is greater tha, that of the anchor; hence as it turns and advances, it goes through the bore of the shank section and then through the bore of the cylindrical core drill section, 18 the screw then emerging from the drill section, as shown in Fig. 14.

In this self-drilling anchor, other than the core of pulverized wall material disposed within the bore of Sthe core drill section, there is nothing to impede passage of the fastener, and as the fastener advances beyond the shank section, it ejects the core of pulverized material from the drill section, which is neither deflected nor split to permit such passage. Hence the integrity of lo the anchor is maintained, and should it be later desirable to unscrew the anchor from the wall, this can be done without difficulty, thereby making it possible to again use the anchor.

While there have been shown and described preferred f embodiments of an improved self-drilling anchor in accordance with the invention, it will be appreciated that many changes and modifications may be made therein without, however, departing from the essential spirit thereof. Thus instead e of the bit of the core drill section being formed by a pair of opposed teeth, the bit may be formed by a circular array of teeth.

ee •a

Claims (16)

1. A self-drilling anchor installable by means of a screwdriver or similar tool in a hollow wall, said anchor comprising: an externally-threaded shank section provided at its upper end with a head s adapted to receive said tool for turning the anchor into the wall, and a longitudinal bore adapted to threadably receive a fastener for holding an object against the outer surface of the wall; and a hollow core drill integral with the shank section, said core drill having at least one cutting member whereby as the anchor is turned into the wall by the tool, the cutting member then bores a round hole in the wall and as the anchor continues to turn, the shank section enters and taps the hole until the head engages the outer surface of the wall to complete the anchor installation, said hollow core drill having a passage therein communicating with the longitudinal bore in the shank section to permit said fastener to advance from the shank section into the core drill.

2. A self-drilling anchor as set forth in claim 1, wherein said cutting member is S" formed by a pair of opposed teeth.

3. A self-drilling anchor as set forth in claim 1, in which the cutting member is formed by a circular array of teeth.

4. A one-piece, self-drilling anchor installable by means of a screwdriver or similar tool in a hollow wall, said anchor comprising: a shank section provided at its upper end with an enlarged head adapted to receive said tool for turning the anchor into the wall, said shank section having a root, a spiral cutting thread surrounding the root, and a longitudinal bore adapted to threadably receive and engage a fastener for supporting an object adjacent the wall; and 25 a hollow drill zone integral with the shank section and extending axially therefrom, said drill zone having at least one cutting edge for drilling a round hole in the S wall having a circular bank and guide means therefor adapted to engage the bank, whereby as the anchor is turned into the wall by the tool, the cutting edge then bores a round hole in the wall whose bank is engaged by the guide means to ensure circularity of the hole, and as the anchor continues to turn, the shank section enters and taps a matching thread in the bank.

A combination of self-drilling anchor installable in a hollow wall by means of a torque-producing tool and a threaded fastener received in the anchor and engaged thereby, to hold an object adjacent the wall, said anchor comprising: an externally-threaded shank section adapted to receive the tool for turning the anchor into a wall in which the anchor is to be installed, the shank section having a longitudinal bore receiving the threaded fastener and tapped thereby to engage the fastener holding said object; and )155:VMJ drilling means integral with the shank section and extending therefrom for drilling a hole of uniform diameter in the wall in which the anchor is to be installed which is tapped by the shank section to secure the anchor to the wall, said drilling means having a passage therein communicating with the bore in said shank section to permit said fastener received in the shank section to advance therebeyond into said passage.

6. The combination of a self-drilling anchor installable in a hollow wall by means of a torque-producing tool and a threaded fastener received in the anchor and engaged thereby to hold an object adjacent the wall, said anchor comprising: an externally-threaded shank section adapted to receive the tool for turning the lo anchor into a wall in which the anchor is to be installed, the shank section having a longitudinal bore receiving the threaded fastener and tapped thereby to engage the fastener holding said object; and drilling means integral with the shank section and extending therefrom for drilling a hole of uniform diameter in the wall in which the anchor is to be installed which 15 is tapped by the shank section to secure the anchor to the wall, said drilling means having a passage therein having a leading portion provided with an opening communicating with the bore in said shank section to permit said fastener received in the shank section to advance therebeyond into said passage.

A self-drilling anchor installable by means of a screwdriver or similar tool in a hollow wall, said anchor comprising: a shank section provided at its upper end with an enlarged head adapted to receive said tool for turning the anchor into the wall, said shank section having a root, a spiral threading surrounding the root, and a longitudinal bore adapted to threadably receive a fastener for holding an object against the outer surface of the wall; and a drill section integral with the shank section and extending axially therefrom, said drill section having at least one cutting member and guide means therefor, whereby as the anchor is turned into the wall by the tool, the cutting member then bores a round hole in the wall whose bank is engaged by the guide means to ensure circularity of the hole, and as the anchor continues to turn, the shank section enters and taps the hole until the head engages the outer surface of the wall to complete the anchor installation; wherein said drill section is constituted by a cylindrical core drill having a longitudinal bore that is generally aligned with the bore of the shank section, said drill having a cutting bit, the exterior cylindrical surface functioning as guide means, whereby a fastener threadably received in the bore of the shank section and having a greater length can pass through the bore of the drill section.

8. An anchor as set forth in claim 7, wherein said anchor is molded of synthetic plastic material. R44/ IN \LIBTTo0155:VMJ C)O~ 7- 0OG:

9. An anchor as set forth in claim 7, wherein said anchor is made of a corrosion resistant metal.

A self-drilling anchor installable in a hollow wall by means of a screwdriver or similar tool, said anchor comprising; an externally-threaded shank section having a longitudinal bore adapted to threadably receive a fastener for holding an object against the wall and provided at its upper end with an enlarged head to receive the tool for turning the anchor into the wall; and a substantially cylindrical core drill section integral with the shank section and lo extending axially therefrom, said drill section having a longitudinal bore substantially aligned with the bore of the shank section whereby a fastener threadably received in the bore of the shank section and having a greater length can pass into the bore of the drill section, said drill section having a bit defined by at least one cutting tooth, whereby when the anchor is pressed into the wall, turning of the tool causes the tooth to drill a hole in the wall whose circularity is ensured by the cylindrical exterior surface of the drill section which acts as guide means, the hole then being entered into by the threaded shank section which taps the hole until the head of the shank section lies against the outer surface of the S wall.

11. An anchor as set forth in claim 10, in which the shank section has a tapered root which is integral with the cylindrical drill section, the diameter of the drill section being equal to that of the root at its junction with the drill section.

12. An anchor as set forth in claim 11, wherein said head has a truncated conical form whose undersurface is provided with an array of teeth which engage the surface of the wall to resist turning out of the anchor.

13. An anchor as set forth in claim 11, wherein said tooth is in a triangular configuration in which the inclined edges define cutting blades and at the apex a point.

14. An anchor as set forth in claim 11, wherein the longitudinal bore in the shank section has a cruciform cross section to define ridges which are tapped by the fastener.

An anchor as set forth in claim 11 made of nylon.

16. A self-drilling anchor substantially as hereinbefore described with reference to Figures 9-14. Dated 9 April, 1996 Louis N Giannuzzi Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON (N:\LIBTTI00155:VMJ