AU4630389A - Panel anchor - Google Patents

Description

TITLE: "PANEL ANCHOR"

TECHNICAL FIELD This invention relates to a panel anchor of the type by means of which a screw may be secured to a panel. The invention will be described with particular reference to securing a screw to a panel but it will be understood also to be applicable for securing a bolt, or similar to other structures such as walls, ceilings and the like.

BACKGROUND ART It is often necessary to attach an object to a panel where it is impossible to find a stud or rafter, in this case the thickness of the panel often provides insufficient anchorage, also normally no access is to be had to the blind side of the panel. A variety of fasteners have been developed which are partly inserted through a hole formed in the panel and expanded on the blind, ox inaccessible, side to grip the panel and provide sufficient anchorage. Examples of such prior art fasteners include toggle bolts and various forms of expansion bolts.

A typical toggle bolt comprises a metallic bolt having a head and a threaded rod, and a spring-loaded wingnut. In use, the wingnut is mounted on the distal end of the rod.

The wings are then collapsed along the sides of the rod before being inserted through a hole in a panel. Once through the hole the wings automatically expand under the influence of the spring and the nut can be tightened, gripping the panel between the nut and bolt head.

Toggle bolts require that the diameter of the hole into which the bolt is to be inserted be larger than the collapsed spring wingnut. Toggle bolts are also relatively costly to manufacture and are unsuitable for soft panel materials such as gyprock and plaster. Furthermore the bolt cannot be changed or removed without loss of the spring wingnut.

An expansion bolt currently in use comprises a bolt having a head and a threaded rod, and a flexible tubular sleeve having longitudinal slits extending between the end portions and an internally threaded portion at one end. In use the bolt is pushed into the unthreaded end of the sleeve and threadably engaged with the further end. The rod and sleeve are then inserted in a hole in a panel until the unthreaded end of the sleeve abuts the sides of the hole. The bolt is then turned to cause the threaded end of the sleeve to be drawn towards the unthreaded end and the slitted portion to expand and grip the back of the panel.

Expansion bolts are more suitable for use with soft panel materials. However, the bolt cannot be removed without the gripping portion collapsing.

Many other forms of fastener exist but each has disadvantages. For example, some exhibit a tendency to rotate about their own axis in the hole when subjected to torsional forces and thus do not remain stationary when the bolt is tightened. Others cannot accommodate different thicknesses of wall.

An object of the present invention is to provide a panel anchor which avoids or at least ameliorates some of the aforementioned disadvantages of the prior art fasteners.

DISCLOSURE OF THE INVENTION

According to the invention there is provided a panel anchor of the type by means of which a screw or bolt or similar may be secured to a panel, wall, ceiling or the like; wherein, the anchor comprises an inner member defining a channel in which a screw may be secured; and an outer member; the inner and outer members being threadably interengageable; the inner member having a relatively rigid radial flange and the outer member having a relatively resilient deformable portion; the arrangement being such that, in use, when the two members of the anchor are interengaged and inserted through a hole in a panel, tightening of the threaded interengagement between the two members causes said deformable portion to extend radially and to co-operate with the flange to grip opposite sides of the panel.

Preferably the resiliently deformable portion comprises a series of longitudinally extending leaves separated by longitudinally extending slits. Preferably a weakpoint or hinge is provided at a point along the length of each leaf so that under longitudinal compressive loads the leaf is caused to _^snap outwards in a direction transverse to the compressive load.

The leaves may be connected at both ends with a relatively rigid annular portion. Alternatively the leaves may be connected only at the end which, in use, is farthest from the radial flange.

The outer member may also be provided with longitudinally extending external ribs to prevent rotation of the panel anchor in the hole through which it is inserted.

The inner member may be provided with internal projections which are cut by the thread of the screw to firmly secure the screw within the channel.

In preferred embodiments, both the inner and outer members are injection moulded. Desirably, the members are made of nylon 11 material which is strong and has thread lubricating properties.

For preference the threads of the inner and outer members are arranged such that introduction of the screw acts in the sense which would cause the panel anchor to grip the panel tighter.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings wherein:

Figure 1 shows an end view of a first member of a panel anchor embodying the present invention;

Figure 2 shows a section taken along line II-II of figure 1;

Figure 3 shows an end view of a second member of a panel anchor embodying the present invention; and

Figure 4 shows a section taken along line IV-IV of figure 3.

Figure 5 shows a series of sectional elecations of the assembled first and second members in use. BEST MODE FOR CARRYING OUT THE INVENTION

The panel anchor comprises an inner member 1 having a tubular body 2 with a rigid radial flange 3 at one end, a central bore 4 or channel and an external thread 5. In the present embodiment, the thread 5 has a saw tooth profile with a thread angle of about 45°. This profile provides a positive connection between inner member 1 and outer member 9 and is particularly suited to injection moulding. Other thread profiles can be used.

Bore 4 has a countersunk opening 6 in flange 3 to remove any sharp edges and provide a lead to help position the screw or bolt that is to be used. In the present example, opening 6 extends at an angle of 45° to the bore axis.

Opening 6 is also provided with four tapered slots 7 to receive the head of a screwdriver. In the present example, the lower surface of the slots extend at an angle of 26.5° to the bore axis and is designed to receive a Phillips head screwdriver.

Tubular body 2 is provided with internal, radially inwardly extending projections 8 which bend and are cut by the thread of a screw as it is inserted and so grip the screw with a locking effect which resists unscrewing.

Referring to figures 3 and 4 the outer member 9 of the panel anchor can be seen to comprise a tubular sleeve having a radial flange 10 at one end and annular sections 11 and 12 at each end connected by deformable leaves 13 which are separated by longitudinal slits 14. Also there is an internal thread 15 integrally formed at end 12 of the member. A series of intermittent ribs 16 extend longitudinally down each leaf 13 from end 11. Each rib has a triangular cross-section.

A series of circumferentially aligned hinges or knee ^■joints 17 τe provided in l«*τe« 13 «- « position approximately mid way along their length. Each knee joint 16 takes the form of a linear decrease in section thickness to provide a less resilient portion that will act as a hinge.

The operation of the anchor will now be described with reference to Figure 5. In use, the end remote from flange 3 of inner member 1 is introduced into end 11 of outer member 9. The outer member 9 is then pushed onto the inner member 1 until threaded portion 15 engages external thread 5, and flange 10 of outer member 9 abuts the underside of flange 3.

The panel anchor assembly can then be pushed through a hole in a panel 18 until outer member 9 is completely buried and flanges 3 and 10 prevent further insertion as shown in Figure 5.

From this position rotation of inner member 1, say by means of a screwdriver inserted into tapering slots 7, causes co-operation of threads 15 and 5 to draw end 12 towards flange 3. The outer member 9 is prevented from rotating by the engagement of ribs 16 with the edges of the hole. Due to the length of the outer member 9 and the low torsional resistance of the structure, there would normally be a tendency for the outer member 9 to twist as the inner member 1 is turned.

This potential problem is overcome by the knee joint 17 providing a weak point in the leaves 13. As the end 12 begins to advance toward flange 10 the resulting compressive load on leaves 13 causes the joints 17 to snap perpendicularly outwards thereby allowing the leaves to deform, without twisting, as shown in Figure 5. The leaves 13 continue to extend outwardly on the blind side of the panel as end 12 advances to co-operate with flanges 3 and 10 to grip panel 18. Ribs 16 are intermittent to facilitate the outward deformation of leaves 13.

A screw 19 may then be threaded into bore 4 of the anchor. As the thread connecting inner member 1 and outer member 9 is of the same handing as the screw 19, the action of tightening the screw is in the sense to reinforce the grip of the anchor even more tightly.

Because grip is effected by the interaction of the two members of the anchor the firmness of the grip is not dependent on the introduction of a screw into the panel anchor, and this in turn provides the advantage that a screw introduced into the panel anchor may be removed without loosening the grip between the anchor and the panel, and without loosing part of the anchor on the blind side of the panel.

As will be apparent to those skilled in the appropriate art, the invention may be embodied in other forms without departing from the scope of the invention herein disclosed. For instance, panel anchors embodying the invention may be of any dimension to accommodate different thic nesses of "wall, likewis slots ^~7 may talce other forms so as to receive other types of screwdrivers, or other tools. Also, the slits 11 and leaves 12 of the outer member 9 need not be longitudinal but could of course be spiral.

In an alternative embodiment the outer member may comprise merely a threaded annular portion from which extend some resilient, or resiliently mounted, flaps which extend axially and radially from the threaded portion and which, in use, engage the blind side of a panel and co-operate with the inner member of the anchor to effect grip.

Claims (10)

1. A panel anchor of the type by means of which a screw or bolt or similar may be secured to a panel, wall, ceiling or the like; wherein, the anchor comprises an inner member defining a channel in which a screw may be secured; and an outer member; the inner and outer members being threadably interengageable; the inner member having a relatively rigid radial flange and the outer member having a relatively resilient deformable portion; the arrangement being such that, in use, when the two members of the anchor are interengaged and inserted through a hole in a panel, tightening of the threaded interengagement between the two members causes said deformable portion to extend radially and to co-operate with the flange to grip opposite sides of the panel.

2. A panel anchor as claimed in claim 1 wherein the outer member comprises a series of longitudinally extending leaves each connected at an end distal to the flange with a relatively rigid first annular portion.

3. A panel anchor as claimed in claim 2 wherein each longitudinally extending leaf is also connected at an end proximal to the flange to a relatively rigid second annular portion.

4. A panel anchor as claimed in claim 3 wherein each leaf is provided with at least one hinge each substantially circumferentially aligned with the hinge of the adjacent leaf.

5. A panel anchor as claimed in claim 4 wherein the hinge is a weak point formed as a linear decrease in section thickness transverse to the length of each leaf.

6. A panel anchor as claimed in any of the preceeding claims wherein the outer member is provided with longitudinally extending ribs to prevent rotation of the panel anchor in the hole through which it is inserted.

7. A panel anchor as claimed in any of the preceeding claims wherein the inner member is provided with one or more deformable radially inwardly extending inner projections.

8. A panel anchor as claimed in any of the preceeding claims wherein the thread connecting the inner and outer member is of the same handing as the threaded fixings to be attached thereto.

9. A panel anchor as claimed in any one of the preceeding claims made from nylon.

10. A panel anchor substantially as herein described with reference to the accompanying drawings.