Patent Description:
The present subject matter relates to wall anchors and, more particularly, to self-drilling anchors for use typically in hollow walls made of friable materials, e.g. plasterboard, gypsum, etc..

The <CIT>, <CIT>and <CIT>, respectively, each disclose an anchor which is turned in a wall made of friable material and is retained in the wall by virtue of the friable material being compressed between the root and deep thread spiraled along the cylindrical body of the anchor and between the proximal end of the thread and flanged end of the anchor which becomes embedded in the front surface of the wall. A work piece is then fastened to the wall by a screw fastener that is screwed into the visible open end of the anchor and holds the workpiece between the flanged end of the anchor and the head of the screw fastener.

Toggle bolts are also known, such as in <CIT>. Generally, a self-drilling toggle anchor includes a drilling member and a toggle member. The drilling member is adapted to drill through the wall hole with the toggle member in its retracted position, i.e. extending axially along the drilling member, whereby the whole anchor is inserted longitudinally in the wall with the toggle member being located completely behind the wall. The toggle member defines a threaded opening that extends transversally therethrough and that has, in the retracted position of the toggle member, its axis perpendicular to the drilling member and to the longitudinal orientation of the whole anchor when it drilled into the wall. In a second step, a screw is rotatably inserted in the anchor and, at one point, a tip of the screw engages the toggle member and causes it to pivot an extended position thereof, wherein the toggle member extends at right angles to the drilling member and to the general orientation of the anchor. The screw then engages the threaded opening of the toggle member. Once the head of the screw abuts the front of the wall or the head of the anchor, it cannot displace longitudinally, such that further rotation of the screw draws the toggle member translationally towards the head of the screw and thus towards the rear face of the wall until is abuts firmly the same, whereby the anchor is fixed to the wall. Alternatively, the drilling tip can be provided on the toggle member, and in such cases, the above drilling member remains similar in that it fixedly depends from the anchor head but it does not perform the drilling action. Such designs are somewhat costly, as the anchor requires two distinct components (e.g. the above drilling and toggle members) that also must be assembled together.

There is also <CIT>, which discloses a self-centering wall anchor (<NUM>, <NUM>) having an outwardly threaded hollow cylindrical body (<NUM>, <NUM>) with a flanged proximal end and a cutting distal end. The hollow cylindrical body diminishes in diameter toward the distal cutting end (<NUM>, <NUM>) in the form of a pointed dome with a pointed centering tip (<NUM>, <NUM>) at the center axis of the anchor. An inner bore (<NUM>, <NUM>) extends continuously from its opening at the proximal end of the anchor along the center axis of the cylindrical body to the centering tip at the distal end where it is partially closed because of the disposition of the centering tip at the center axis. The distal end of the bore is in the form of a deep flute (<NUM>, 105a) which communicates and is part of the inner bore and is defined at its outer edges by a leading cutting edge (<NUM>, <NUM>) and a trailing edge (<NUM>, <NUM>) of the single cutter, with the leading cutting edge extending from the pointed tip in a curved distention. In one instance, the outer thread extends to the centering tip and is interrupted in the area of the bore opening to assure optimum access to material cut from the wall as the anchor is rotated.

Furthermore, <CIT>et al. , which discloses an anchor (<NUM>) for mounting to a hollow wall (W) made of friable material comprises a proximal flanged end (<NUM>) adapted to be engaged by a rotatable tool (<NUM>) to rotate the anchor (<NUM>) about a longitudinal axis (A) thereof and to cause it to gradually engage the wall (W). The anchor (<NUM>) also includes a distal end (<NUM>) adapted to cut through the wall (W) as the anchor (<NUM>) is rotated, and a shank (<NUM>) extending between the proximal and distal ends (<NUM>, <NUM>). The shank (<NUM>) includes at least one expandable leg (<NUM>) that is in a collapsed position thereof when the anchor (<NUM>) is rotated to mount it to the wall (W) and that is located distally beyond a non visible surface of the wall (W) once the anchor (<NUM>) has been mounted to the wall and is in a first position thereof. The wall anchor (<NUM>) includes an outer thread (<NUM>) that securely engages the wall (W). A threaded fastener (B), e.g. a screw, is adapted to be introduced in the anchor (<NUM>) and to threadably engage the same distally of the leg (<NUM>) such that sufficient rotation of the threaded fastener (B) retracts the distal end (<NUM>) towards the proximal end (<NUM>) thereby causing the leg (<NUM>) to displace to a laterally expanded position thereof and to engage the non visible surface of the wall (W).

<CIT> discloses a toggle bolt fastener assembly that comprises a tubular toggle housing body defining a longitudinal axis and within which a nut member is guidably moved in a translational manner. A pair of toggle wing members are pivotally mounted upon the nut member, and the nut member includes a lug structure for cooperating with a first pair of longitudinal slots formed within first opposite side wall portions of the housing body so as to prevent relative rotation of the nut member with respect to the housing body. A second pair of longitudinal slots are formed within second opposite side wall portions so as to permit the wing members to be movable therethrough between radially contracted and expanded positions. A pair of compression sleeve members are provided upon the housing body for forcing the wing members to their radially contracted positions when the nut member is disposed at a first translational position, whereas when the nut member is disposed at a second translational position at which the wing members are disengaged from the compression sleeve members, the wing members attain their radially expanded positions.

It would therefore be desirable to provide a self-drilling anchor assembly typically for use with a fastener in hollow walls.

It would thus be desirable to provide a novel anchor assembly typically for use with a fastener in hollow walls.

The embodiments described herein provide in one aspect a wall anchor for mounting to a hollow wall, comprising a main body and an anchor member, the main body including a proximal end adapted to be engaged by a rotatable tool to rotate said anchor about a longitudinal axis thereof and to cause it to gradually engage a wall, a distal end adapted to cut through the wall as said anchor is rotated, and a shank between said proximal and distal ends, said shank defining at least one slot, the anchor member including at least one expandable wing and a body defining a hole, the expandable wing being in registry with the slot and being displaceable between inwardly collapsed and outwardly expanded positions, said expandable wing being in the collapsed position thereof when said anchor is rotated to mount it to the wall and being located distally past a rear surface of the wall once said anchor is mounted to the wall, said anchor being adapted to receive therein a threaded fastener and to threadably engage the body of the anchor member distally of said wing such that sufficient rotation of the threaded fastener retracts said body of the anchor member towards said proximal end thereby causing said expandable wing to extend outwardly through the slot to the expanded position of the expandable wing.

For a better understanding of the embodiments described herein and to show more clearly how they may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, which show at least one exemplary embodiment, and in which:.

<FIG> illustrate a self-drilling wall anchor A, which is adapted to be mounted to a wall W for use with a fastener, such as a screw. The wall anchor A includes a rigid main body <NUM> and deformable anchor member <NUM>.

The main body <NUM> includes a flanged proximal head <NUM> adapted to be engaged for instance by a powered bit, e.g. Philips, via a cruciform recess <NUM> defined in the proximal head <NUM>. The main body <NUM> also includes a distal end <NUM>, defining an open flute or opening <NUM>, and an outer thread <NUM> interrupted by the flute <NUM>. The distal end <NUM> is adapted to dig into the wall W and allow the anchor A to penetrate therein.

Between the proximal head <NUM> and the distal end <NUM>, the main body <NUM> includes a central substantially cylindrical section <NUM>, which includes a pair of fins <NUM> adapted to be lodged in the wall W once the anchor A has been installed therein. The cylindrical section <NUM> also defines four longitudinal slots <NUM>.

The deformable anchor member <NUM> includes a rigid body <NUM> defining a hole <NUM> that is adapted to be tapped by a screw S, and four (<NUM>) deformable expansion wings or legs <NUM>. The anchor member <NUM> is positioned within the cylindrical section or shank <NUM> of the main body <NUM>, and with the deformable expansion legs <NUM> being lodged in the slots <NUM>. The hole <NUM> could also define inner female threads that are adapted to mate with the male threads of the screw S.

To install the wall anchor A in the wall W, a screwdriver bit is inserted in the recess <NUM> and the distal end <NUM> is abutted onto the wall W, typically on a visible surface of a hollow wall. The screwdriver bit is rotated (typically via a powered drill) such that the distal end pierces the wall W and the anchor A is gradually introduced in the wall, that is until a flange <NUM> of the proximal head <NUM> reaches the wall W. In this position, the anchor member <NUM> is located behind the wall and the fins <NUM> are lodged in the wall W.

Then, the screw S is introduced in the anchor A via the recess <NUM>, and the screw S is adapted to eventually engage the rigid body <NUM> of the anchor member <NUM> at the hole <NUM> thereof. Once a head of the screw S reaches the flange <NUM> of the proximal head <NUM>, the screw S cannot further translationally advance, whereby continued rotation thereof (via the bit) causes the rigid body <NUM> to displace towards the wall W, thereby causing the deformable expansion legs <NUM> thereof to expand outwardly, through the slots <NUM>, and into a general cruciform configuration, as seen in <FIG>, <FIG> and <FIG>. The expanded legs <NUM> abut the hidden side H of the wall W, thereby preventing the wall anchor A from being pulled out of the wall W, with the wall anchor being thus firmly engaged to the wall W.

Now turning to <FIG>, a variant wall anchor A' is illustrated in <FIG>, which wall anchor A' is similar to the wall anchor A of <FIG>, whereby in the following description and drawings that pertain to the wall anchor A', components of wall anchor A' which are identical in function and identical and/or similar in structure to corresponding components of the wall anchor A of <FIG> (and <FIG>) bear the same reference as in <FIG>, but are tagged with the prefix "<NUM>" and are thus in the hundreds with the last two digits thereof being identical to the reference numerals of corresponding components of wall anchor A. New components (or components not identified for wall anchor A) provided for wall anchor A' start at reference numeral <NUM>.

Generally, both wall anchors A and A' are similar, except for there being four (<NUM>) longitudinal slots in wall anchor A, whereas there are three (<NUM>) such longitudinal slots in wall anchor A'. Also, the deformable expansion legs <NUM> in the wall anchor A' include distinct hinges. Furthermore, the pair of fins <NUM> of wall anchor A are replaced in wall anchor A' by a thread, which thread extends all the way to the distal end <NUM>, being interrupted by the longitudinal slots <NUM> and by the open flute <NUM>. As the thread in wall anchor A' extends to, and merges with, the outer tread provided at the distal end <NUM>, the complete outer thread in anchor A', which extends from the proximal head <NUM> to the distal end <NUM>, bears the reference numeral <NUM>.

Therefore, <FIG> illustrate a self-drilling bi-material wall anchor A', which is adapted to be mounted to the wall W for use with a fastener, such as the screw S. The wall anchor A' includes a rigid main body <NUM> and a deformable anchor member <NUM>. The rigid main body <NUM> is typically made with a "charged" material (for instance, a plastic such as nylon that is reinforced with fiberglass) for cutting and penetrating the wall W. The deformable anchor member <NUM> is typically made of a "non charged" material (for instance, a plastic without fiberglass) to provide the required flexibility, e.g. in the legs <NUM>. The two materials, namely the material of the rigid main body <NUM> and the material of the anchor member <NUM>, are non-bounding materials to allow for their independent functions and, more particularly, for allowing the legs <NUM> of the latter to displace relative to the former while retaining their chemical integrity.

The main body <NUM> includes a proximal head <NUM>, which defines a flange <NUM> and which is adapted to be engaged for instance by a powered bit, e.g. of Philips configuration, via the cruciform recess <NUM> defined in the proximal head <NUM>. The main body <NUM> also includes a distal end <NUM>, with a "side" opening or open flute <NUM> being defined therein, with an outer thread <NUM> being provided on the distal end <NUM> although interrupted by the flute <NUM>. As previously mentioned, the outer thread <NUM> in the wall anchor A' (distinctively from the outer thread <NUM> of the wall anchor A of <FIG>) extends from behind the flange <NUM> of the proximal head <NUM> generally continuously all the way to the distal end <NUM>, the outer thread <NUM> being interrupted by the longitudinal slots <NUM> and by the flute <NUM>.

When the anchor A' is rotated, typically via a powered screwdriver bit engaged in the cruciform recess <NUM>, the distal end <NUM> is adapted to dig into the wall W and allow the anchor A' to penetrate therein.

Between the proximal head <NUM> and the distal end <NUM>, the main body <NUM> includes a central substantially cylindrical section <NUM>, which defines the three longitudinal slots <NUM>.

The deformable anchor member <NUM> includes a distal rigid body <NUM> defining a hole <NUM> that is adapted to be tapped by the screw S, and three (<NUM>) deformable expansion legs <NUM> located proximally of the rigid body <NUM>. The anchor member <NUM> is positioned within the cylindrical section or shank <NUM> of the main body <NUM>, and with the rigid body <NUM> acting basically as a nut (inwardly unthreaded or female-threaded) and being located substantially within a distal end of the cylindrical section <NUM> and with the deformable expansion legs <NUM> being lodged, in registry, along the longitudinal slots <NUM>. The hole <NUM> could also define inner female threads that are adapted to mate with the male threads of the screw S.

To install the wall anchor A' in the wall W, a screwdriver bit is inserted in the recess <NUM> and the distal end <NUM> is abutted onto the wall W, typically on a visible surface of the hollow wall W. The screwdriver bit is rotated (typically via a powered drill) such that the distal end <NUM> pierces the wall W and the anchor A' is gradually introduced in the wall W, that is until the flange <NUM> of the proximal head <NUM> reaches the wall W. In this position, the anchor member <NUM> is located behind the wall W and the proximal section of the outer thread <NUM> is lodged in the wall W.

Then, the screw S is introduced in the anchor A' via the recess <NUM>, and the screw S is adapted to eventually engage the rigid body <NUM> of the anchor member <NUM> at the hole <NUM> thereof, with the screw S either self-tapping the rigid body <NUM> or threadably engaging the internal thread of the rigid body <NUM> if the rigid body <NUM> already includes a female thread. Once a head of the screw S reaches the flange <NUM> of the proximal head <NUM>, the screw S cannot further translationally advance, whereby continued rotation thereof (via the bit) causes the rigid body <NUM> to displace towards the wall W (as the rigid body <NUM> is threadably engaged to the screw S), thereby causing the deformable expansion legs <NUM> thereof to expand outwardly, through the slots <NUM>, and into a general tripodal configuration, as seen in <FIG>, <FIG> and <FIG>, wherein the expanded legs <NUM> extend radially beyond the outer threads <NUM>. The expanded legs <NUM> abut the hidden side H of the wall W, thereby preventing the wall anchor A' from being pulled out of the wall W, with the wall anchor A' being thus firmly engaged to the wall W.

The wall anchor A' is held captive to the wall W both by the engagement of the proximal section of the threads <NUM> of the main body <NUM> within the wall W and by the legs <NUM> of the rigid body <NUM> abutting the hidden side H of the wall W.

Each expansion leg <NUM> includes a pair of cuts defined in the outside thereof, which act as hinges, as well as an angled proximal foot <NUM>. The proximal foot <NUM>, when the anchor member <NUM> is pulled by the screw S, is adapted to outwardly climb along the cylindrical portion <NUM> at a proximal end of the longitudinal slot <NUM>, as seen in <FIG>, <FIG> and <FIG>. At the end of the installation, the proximal foot <NUM> lies, generally flat, against the hidden side H of the wall W (see <FIG>).

As to the pair of cuts defined in each expansion leg <NUM>, these cuts include a distal higher cut <NUM> and a typically more pronounced proximal lower cut <NUM>. The distal higher cuts <NUM> are adapted to control the positioning of the legs <NUM> at the back of the wall W and a solid fold back of the distal portion of each leg <NUM>, adjacent the rigid body <NUM>. The proximal lower cuts <NUM> basically are adapted to force the proximal free end or foot <NUM> of each leg <NUM> to bind flat on the hidden side H of the wall W.

Typically, the anchor member <NUM> will include two, three or four expansion legs <NUM>.

Claim 1:
A wall anchor (A, A') for mounting to a hollow wall (W), comprising a main body (<NUM>, <NUM>) and an anchor member (<NUM>, <NUM>), the main body (<NUM>, <NUM>) including a proximal end adapted to be engaged by a rotatable tool to rotate said anchor (A, A') about a longitudinal axis thereof and to cause it to gradually engage a wall (W), a distal end (<NUM>, <NUM>) adapted to cut through the wall (W) as said anchor (A, A') is rotated, and a shank (<NUM>, <NUM>) between said proximal and distal ends, said shank (<NUM>, <NUM>) defining at least one slot (<NUM>, <NUM>), the anchor member (<NUM>, <NUM>) including at least one expandable leg (<NUM>, <NUM>) and a body (<NUM>, <NUM>) defining a hole (<NUM>, <NUM>), the expandable leg (<NUM>, <NUM>) being in registry with the slot (<NUM>, <NUM>) and being displaceable between inwardly collapsed and outwardly expanded positions, said expandable leg (<NUM>, <NUM>) being in the collapsed position thereof when said anchor is rotated to mount it to the wall (W) and being located distally past a rear surface of the wall (W) once said anchor (A, A') is mounted to the wall (W), said anchor (A, A') being adapted to receive therein a threaded fastener (S) and to threadably engage the body (<NUM>, <NUM>) of the anchor member (<NUM>, <NUM>) distally of said leg (<NUM>, <NUM>) such that sufficient rotation of the threaded fastener (S) retracts said body (<NUM>, <NUM>) of the anchor member (<NUM>, <NUM>) towards said proximal end thereby causing said expandable leg (<NUM>, <NUM>) to extend outwardly through the slot (<NUM>, <NUM>) to the expanded position of the expandable leg (<NUM>, <NUM>),
characterized in
that the main body (<NUM>, <NUM>) and the anchor member (<NUM>, <NUM>) are distinct components assembled together to form the anchor, wherein the main body (<NUM>, <NUM>) is substantially rigid, whereas the anchor member (<NUM>, <NUM>) is deformable at least at the expandable leg (<NUM>, <NUM>) thereof.