An anti-ligature wall mount

Abstract

An anti-ligature wall mount comprises a wall plug 12, 14, a mounting panel 7 and a screw 20 for fixing the mounting panel to the wall plug. The screw 20 is configured to break to release the mounting

Description

FIELD OF THE INVENTION The present invention relates to an anti-ligature wall mount, in particular a wall mount configured to break away from a wall in the event of its use to support a ligature. BACKGROUND OF THE INVENTION Facilities such as mental health units are commonly fitted with anti-ligature devices to keep patients safe, and such devices typically aim to prevent room fixtures from acting as an anchor point for a ligature. Some devices aim to prevent attachment of a ligature, and / or have breakable components that break under a threshold load beyond what the fixture should typically encounter during its intended use. Many fixtures are wall mounted, and may for example include light fixtures, towel rails, curtain rails, wall handles, etc. One of the problems with known solutions is that they are typically very costly, and prone to breakage, either accidental or deliberate. In the event of breakage, the whole device may require replacement at significant cost. It is therefore an object of the invention to provide an improved anti-ligature device. SUMMARY OF THE INVENTION According to a first aspect of the invention, there is provided an anti-ligature wall mount as defined in claim 1. The anti-ligature wall mount comprises a wall plug and a screw for fixing a mounting panel to the wall plug. The wall plug may be inserted into a hole in a wall, and then the screw may be screwed through the mounting panel and into the wall plug to secure the mounting panel to the wall. Typically, the mounting panel is part of, or is intended to secure, a room fixture. The mounting panel may be part of the anti-ligature wall mount, for example if the mounting panel is intended to secure the room fixture, or the mounting panel may not be part of the anti-ligature wall mount, for example if the mounting panel is part of the room fixture. The room fixture may for example be a light fixture, towel rail, curtain rail or wall-mounted handle. The mounting panel may comprise an aperture, and the screw may comprise a shaft and a head at one end of the shaft, the shaft configured to pass through the aperture and the head being wider than the aperture. Accordingly, the head of the screw may retain the mounting panel on the wall once the shaft has been screwed into the wall plug. The screw is configured to break to release the mounting panel from the wall plug upon application of greater than a threshold force, for example a force pulling the mounting panel away from the wall plug. Thus, if a person attempts to support their weight via the mounting panel, then the mounting panel will break away from the wall when the screw breaks. Since the screw breaks, the anti-ligature wall mount can be repaired and re-used simply through the installation of a new screw, which is cost-effective and straightforward to do. The screw may be formed of a plastics material to provide the desired breaking force. For example, a screw formed of styrene may provide the desired physical size and breaking force characteristics. The screw may for example be configured to break once the force exerted along it exceeds a threshold force, wherein the threshold force is less than 600N. For example, the threshold force may be 400N or 500N, so that the mounting panel will not be able to support the weight of a person attempting to suspend themselves from the mounting panel / room fixture. To prevent unauthorised persons from tampering with the screw, the wall mount may comprise an anti-tamper cover configured to snap over a tool interface of the screw and block access to the tool interface. The tool interface may for example be an interface for engaging with a screwdriver, hex tool or spanner. The anti-tamper cover may comprise a smooth and continuous cylindrical surface in the shape of a cylinder, and a smooth and continuous end surface at an end of the cylinder. An opposite end of the cylinder may comprise barbs for snapping over the head of the screw, and the head of the screw may comprise a circumferentially extending groove for receiving the barbs. The wall plug may comprise an outer body that surrounds a cavity for receiving the screw, the outer body configured to compress against internal surfaces of a hole in a wall to retain the wall plug in the wall. Typically, the installer will drill a hole into the masonry of the desired wall, and then push or hammer the wall plug into the hole. The outer body may be formed of a flexible plastics material, for example polypropylene, to allow it to deform slightly as it is inserted into the hole, helping to retain the wall plug in the hole. The outer body may comprise one or more outwardly protruding barbs to help resist withdrawal of the outer body from the hole. The wall plug may comprise a female screw thread within the cavity, the female screw thread for receiving the screw. So, there is no need for the screw to self-tap as it enters the cavity, and the risk of accidentally breaking the screw during installation is reduced. The female screw thread may be formed of a separate and more rigid material than the outer body, so that the female screw thread is not significantly affected by any deformation of the outer body that takes place when the wall plug is inserted into the wall. The female screw thread may be part of an insert that has been inserted into the cavity, and the insert may improve the structural strength of the wall plug and enable the wall plug to exert a greater force against the sides of the hole than would be possible without the insert. Therefore, if the outwardly protruding barbs are present then they may be formed at a same axial position along the outer body as the insert. The insert and therefore the female screw thread may be formed of a metal for strength, and the metal may be stainless steel to resist corrosion and improve consistency. The insert may be fixed within the cavity, for example the insert may comprise an external screw thread which is screwed into the cavity, and the external screw thread may self-tap into the walls of the cavity that are defined by the outer body. The insert may be screwed into the cavity during manufacture of the wall plug. Whilst the screw is passed through the mounting panel and screwed into the cavity in the outer body of the wall plug, the screw may not press significantly against the outer body, and so the outer body may remain unchanged in shape. For example, the screw may not contact the outer body, and may optionally only engage the female screw thread of the wall plug. Thus, there is no relationship between the extent of deformation of the outer body of the wall plug in the hole and the force required to screw in the screw, and so there is no risk of the screw accidentally breaking under the force required to screw it in. The outer body may be shaped as a cylinder, to compliment and fit closely within a cylindrical hole as may be drilled into a wall. DETAILED DESCRIPTION Embodiments of the invention will now be described by way of non-limiting example only and with reference to the accompanying drawings, in which: Fig. 1 shows a schematic front view of an anti-ligature wall mount in accordance with an embodiment of the invention, fixing a mounting panel to a portion of a wall; Fig. 2 shows a schematic cross-sectional diagram taken along line A-A marked on Fig. 1; and Fig. 3 shows a schematic exploded diagram of a wall plug and screw of the anti-ligature wall mount of Fig. 1. The figures are not to scale, and same or similar reference signs denote same or similar features. Embodiments of the invention will now be described with reference to Figs. 1 to 3, in which Fig. 1 shows an anti-ligature wall mount 10 being used to attach a mounting panel 7 to a wall 5. The mounting panel 7 is only shown in schematic form, and may for example be a base part of a towel rail, curtain rail, light fixture, wall handle, etc. The wall 5 is normally formed of brick or concrete, however could alternatively be formed of other common building materials if desired, for example plasterboard or wood. The schematic diagram of Fig. 2 is a cross-sectional view taken along line A-A marked on Fig. 1. As shown, the anti-ligature wall mount 10 may comprise a wall plug 11 and a screw 20. The wall plug 11 has been forcibly inserted into a hole 6 that was drilled into the wall 5. The screw 20 has been passed through the mounting panel 7 and into the wall plug 11, to secure the mounting panel 7 to the wall 5. The wall plug 11 may comprise an outer body 12 and an insert 14 within a cavity 13 of the outer body. The outer body 12 may have a cylindrical shape (see Fig. 3) with an opening at one end, the opening for receiving the screw and leading into the cavity 13. The outer body may be moulded from a flexible plastics material such as polypropylene. In this embodiment, the outer body comprises four outwardly protruding barbs 17 that protrude outwardly away from a central longitudinal axis AX1 of the wall plug. As shown in Fig. 3, each barb 17 may comprise a catch surface 17a, and each catch surface 17a may extend perpendicular to the central longitudinal axis, or extend towards the opening at the end of the outer body as the catch surface 17a extends away from the central longitudinal axis. The insert 14 may be a cylindrical tube which is inserted into the cavity 13 of the outer body, and the screw 20 may be screwed into the cylindrical tube to anchor the screw to the wall plug. The insert 14 may be fixed inside the cavity 13 of the outer body 12 using screw threads. In this embodiment, the insert 14 comprises an external screw thread 16 that is formed in the exterior surface of the cylindrical tube defining the insert 14. The insert 14 may be a tight fit within the cavity 13, and may be screwed into the cavity 13 during manufacture of the wall plug. The external screw thread 16 may self-tap a corresponding screw thread into internal surfaces of the outer body 12 that define the cavity 13. Alternatively the corresponding screw thread may be moulded into the internal surfaces of the outer body during manufacture of the outer body, rather than tapped by the insert 14. The insert 14 may also comprise a female screw thread 15 that is formed in the interior surface of the cylindrical tube. The female screw thread 15 is sized to mesh with a screw thread 24 of the screw 20. The insert 14 may be formed of a more rigid material than the outer body 12, and so the outer body 12 is able to deform whilst being inserted into the hole 6, whilst the insert 14 resists deformation so the ability of the screw 20 to be screwed into the insert 14 is unaffected by the deformation of the outer body 12. The insert 14 may for example be a metal such as brass or more preferably stainless steel for high strength and longevity. The screw 20 may comprise a shaft 23 and a head 21 at one end of the shaft 23. The head 21 may comprise a tool interface 22 for turning the screw with a tool to screw the screw into the insert 14, and / or the head may comprise a knurled circumferential surface 26 to allow the screw to be turned by hand. The shaft 23 comprises the screw thread 24 along the length of the shaft, for screwing into the female screw thread 15 of the insert. The screw thread 24 may have a uniform cross-section along the length of the shaft, for meshing with the female screw thread 15. The screw 20 may formed of a frangible material that will break once greater than a threshold force is applied between the shaft and the head of the screw, for example styrene. The screw may be sized so that breakage will occur when the tensional force between the shaft and the head exceeds the threshold force. The screw may comprise an anti-tamper cover 25 that snaps over the head 21 of the screw to block access to the tool interface 22 and knurled surface 26. For example, the anti-tamper cover 25 may comprise a smooth and continuous cylindrical surface 25b in the shape of a cylinder to cover the knurled surface 26, and a smooth and continuous end surface 25a at an end of the cylinder to cover the tool interface 22. An opposite end of the cylinder may comprise barbs 25c for snapping over the head of the screw, and for locating into a circumferentially extending groove around the head of the screw. The anti-tamper cover may make the anti-ligature wall mount more resilient to tampering by unauthorised persons. In use, an installer of the room fixture may drill the hole 6 into the wall 5, for example the hole 6 may be 10mm wide, and may be around 50mm deep. The wall plug 10 may then be forced into the hole, for example using a hammer, until it has been fully inserted into the hole. Thus, the outer body 12 is compressed against the interior surface of the hole 6 to help retain the wall plug in the hole 6. The outwardly extending barbs 17 may be at a same axial position along the outer body 12 as the insert 14, and so the rigid insert 14 may increase the force exerted against the interior surface of the hole 6 by the barbs 17. The barbs 17 and their catch surfaces 17a then prevent withdrawal of the wall plug 10 from the hole 6. The shaft 23 of the screw 20 is then passed through an aperture in the mounting panel 7, and screwed into the insert 14. The head 21 of the screw is wider than the aperture and so the mounting panel 7 is captured between the wall 5 and the head 21 of the screw. The screw 20 normally only contacts the female screw thread 15 of the wall plug, and not the outer body 12, and so the torque required to turn the screw is unaffected by any deformation of the outer body 12 within the hole 6, and the outer body 12 of the wall plug remains unchanged in shape whilst screwing the screw 20 into the wall plug 10. The installer continues to screw the screw 20 into the female thread 15 until the mounting panel 7 is secured against the wall 5, and then snaps the anti-tamper cover over the head 21 of the screw. If a person attempts to pull more strongly on the room fixture than should occur during the normal use of the room fixture, then the mounting panel 7 of the room fixture will exert greater than the threshold force on the head 21 of the screw 20, and the screw 20 will break, releasing the room fixture from the wall. The remaining shaft 23 of the screw can be unscrewed from the female thread 15, for example using pliers, and then a new screw 20 can be used to replace the broken screw, to re-attach the mounting panel 7 to the wall again. Many other variations of the described embodiments falling within the scope of the invention will be apparent to those skilled in the art.

Claims

1. An anti-ligature wall mount, comprising a wall plug and a screw for fixing a mounting panel to the wall plug, wherein the screw is configured to break to release the mounting panel from the wall plug upon application of greater than a threshold force.

2. The anti-ligature wall mount of claim 1, wherein the wall plug comprises an outer body that surrounds a cavity for receiving the screw, the outer body configured to compress against an interior surface of a hole in a wall to retain the wall plug in the wall.

3. The anti-ligature wall mount of claim 2, wherein the outer body of the wall plug remains unchanged in shape whilst screwing the screw into the cavity.

4. The anti-ligature wall mount of claim 2 or 3, wherein the wall plug comprises a female screw thread within the cavity, the female screw thread for receiving the screw.

5. The anti-ligature wall mount of claim 4, wherein the female screw thread is formed of a separate and more rigid material than the outer body.

6. The anti-ligature wall mount of claim 5, wherein the female screw thread is formed of a metal.

7. The anti-ligature wall mount of claim 6, wherein the female screw thread is formed of stainless steel.

8. The anti-ligature wall mount of any one of claims 4 or 7, wherein the wall plug comprises an insert that is fixed within the cavity and that comprises the female screw thread.

9. The anti-ligature wall mount of claim 8, wherein the insert comprises a external screw thread that has been screwed into the outer body to fix the insert within the outer body and the cavity.

10. The anti-ligature wall mount of any one of claims 2 to 9, wherein the outer body comprises one or more outwardly protruding barbs for resisting withdrawal of the outer body from the hole.

11. The anti-ligature wall mount of claim 10 when appended to any one of claims 8 and 9, wherein the one or more outwardly protruding barbs are at a same axial position along the outer body as the insert.

12. The anti-ligature wall mount of any one of claims 2 to 11, wherein the outer body is cylindrical.

13. The anti-ligature wall mount of any preceding claim, comprising a mounting panel having an aperture, and wherein the screw comprises a shaft and a head at one end of the shaft, the shaft configured to pass through the aperture and the head being wider than the aperture.

14. The anti-ligature wall mount of any preceding claim, wherein the screw is formed of a plastics material.

15. The anti-ligature wall mount of any preceding claim, wherein the screw is formed of styrene.

16. The anti-ligature wall mount of any preceding claim, comprising an antitamper cover configured to snap over a tool interface of the screw and block access to the tool interface.

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