CORNER BEAD ASSEMBLY

The present invention relates to a corner bead assembly for applying to an external corner between two intersecting surfaces prior to the application of a surface coating thereto.

It is well known to apply a surface coating of plaster or other render material, to ceilings and other wall surfaces in buildings. Generally, prior to applying the plaster or the material, an elongate corner bead of metal is applied along external corners where two intersecting surfaces meet, in order to enable a good finish to be achieved to the corner. The corner bead also acts to strengthen and protect the corner.

US Patent No 4,876,837 discloses a typical corner bead which is formed from an elongate strip of sheet metal and comprises a rounded nose and two mounting flanges extending perpendicular to each other from the opposite sides of the nose. The mounting flanges are apertured to provide a key for the overlying plaster or render.

The corner bead is applied to a corner by passing nails or screws through the apertured mounting flanges into the underlying wall material. However, a disadvantage of this arrangement is that the underlying wall material is often too hard or too soft to readily accept nails or screws and thus the process of applying corner beads can be difficult and time consuming. In order to overcome this problem, it is has been proposed to attach corner beads using an adhesive. However, the corner beads have to be held in place whilst the adhesive sets and it will be appreciated that this is equally as difficult as permanently securing the corner beads. Another disadvantage of using adhesive is that the adhesive has to be allowed to set before the underlying wall is plastered or rendered.

US Patent No 5,778,617 discloses a corner bead which attempts to overcome the above-mentioned problems and which comprises a plurality of integral pre-formed barbs along its length for securing the corner bead to underlying wall surfaces formed of plasterboard or other drywall material. In use, when a corner bead is applied to the plasterboard the barbs penetrate the outer layer of the plasterboard and temporarily secure the corner bead to the corner whilst it is plastered over. A disadvantage of this arrangement is that the barbs will not penetrate hard surfaces, such as surfaces formed at least partially of bricks or blocks.

I have now devised a corner bead assembly which alleviates the above-mentioned problems.

In accordance with this invention, there is provided a corner bead assembly comprising a corner bead member having a pair of elongate longitudinally-extending flanges which are mounted substantially perpendicular to each other and which have opposed front surfaces and outwardly-directed rear surfaces, the flanges extending forwardly from a longitudinally extending corner formation, the assembly further comprising a plurality of clips mounted to the front of the corner bead member at respective selective longitudinal positions thereon, each clip comprising a pair of arms mounted substantially perpendicular to each other, the rear surfaces of the arms lying in face-to-face registration with the respective front surfaces of the flanges of the body portion, each arm comprising a plurality of barbs on its front surface.

In use, the user can position the clips at selective locations along the length of the corner bead member of the corner bead assembly to align with points on the underlying wall surface with which the barbs can engage. For example in a brick wall, the clips may be aligned with respective courses of mortar between adjacent rows of bricks, the barbs being able to penetrate the mortar more easily than the brick material.

Preferably the clips are slidably mounted to the corner bead member.

Preferably the outer ends of the arms of the clips are arranged to engage over respective opposite longitudinal side edges of the respective flanges of the corner bead member.

The arms of each clip may comprise generally parallel inner and outer portions interconnected at their respective outer ends and arranged to respectively lie in face-to- face registration with the front and rear surface of respective flanges of the corner bead member, the inner ends of the inner portions of the arms of each clip being interconnected. The clips thus grasp the flanges of the corner bead member, thereby retaining them in engagement with the corner bead member.

The inner and outer arm portions may be arranged to engage each other through apertures formed in the flanges of the corner bead member.

Preferably the clips are formed of a resiliently flexible material which allows the inner and outer arm portions to be separated when engaging the clips with the corner bead member.

The corner formation may comprise a nose defining a channel extends longitudinally of the nose on the front face of the corner bead member, the clips being slidably mounted to the channel. Most conventional corner bead members are formed by roll-forming a strip of galvanised metal into shape. The nose is formed by deforming a central longitudinally-extending portion of the strip rearwardly between the flanges: this creates a forwardly-facing channel having a re-entrant mouth, which can be utilised as an attachment point for the clips.

Preferably the clips are formed of metal.

Also in accordance with this invention, there is provided a method of applying a corner bead to an external corner formed between two wall surfaces, the method comprising: providing a corner bead member having a pair of elongate longitudinally- extending flanges which are mounted substantially perpendicular to each other and which have opposed front surfaces and outwardly-directed rear surfaces, the flanges extending forwardly from a longitudinally corner formation; providing a plurality of clips, each clip comprising a pair of arms mounted substantially perpendicular to each other and a plurality of barbs on the front surface of each arm; mounting each clip to the front of the corner bead member at respective selective longitudinal positions thereon to align with respective regions of the wall surfaces, the rear surfaces of the arms lying in face-to-face registration with the respective front surfaces of the flanges of the body portion; positioning the corner bead assembly on said corner so that said flanges are positioned against respective wall surfaces; and pressing the corner bead assembly against said corner so that the barbs of said clips respectively grip said selected regions of the wall surfaces.

Preferably the position of at least one of the clips is adjusted prior to said positioning step by sliding it longitudinally of the corner bead member.

Embodiments of this invention will now be described by way of examples only, and with reference to the accompanying drawings in which:

Figure 1 is a front view of an embodiment of corner bead assembly in accordance with the present invention;

Figure 2 is a plan view of the corner bead assembly of Figure 1 ;

Figure 3 is a perspective view of the corner bead assembly of Figure 1 ;

Figure 4 is a perspective view of a clip of the corner bead assembly of Figure 1 ;

Figure 5 is a perspective view illustrating how the corner bead assembly of Figure 1 can be attached to a brick wall;

Figure 6 is a perspective view showing the corner bead assembly of Figure 1 attached to the brick wall;

Figure 7 is a perspective view of a clip of an alternative embodiment of corner bead assembly in accordance with the present invention; and

Figure 8 is a plan view of the corner bead assembly of Figure 7.

Referring to Figures 1 to 4 of the drawings, there is shown an embodiment of corner bead assembly 10 comprising a conventional elongate corner bead 11 , which is roll- formed from an elongate strip of galvanised steel. The corner bead 11 comprises a pair of longitudinally-extending flanges 12, which are mounted substantially perpendicular to each other and which have opposed front surfaces and outwardly-directed rear surfaces. The flanges 12 extend forwardly from a longitudinally-extending u-section nose 13, which projects rearwardly of the corner bead 1 1.

The nose 13 is formed by deforming the metal strip rearwardly into an n-shape between the flanges 12 to form a forwardly-facing channel 14, which extends longitudinally of the corner bead 11 . The mouth of the channel 14 is preferably narrower in width than the inner portion thereof.

A plurality of apertures and slots 15 are formed in the flanges 12 to provide a means by which plaster can key to the corner bead assembly 10.

A plurality of L-shaped clips 16 of metal are provided for attaching to the front of the corner bead member 1 1 at selected longitudinal positions thereon. Each clip 16 comprises a pair of arms 17, which are mounted perpendicular to each other and which extend from a central web 18. The web 18 is n-shaped in section and extends rearwardly of the clip in a similar manner to the nose 13 of the corner bead 11 . The outer ends of the arms 17 of the clips 16 are turned outwardly and rearwardly to form hooks 19. A plurality of barbs 20 are provided on the front face of each arm 17, the barbs 20 preferably being formed by punching out portions of the metal of the arms 17. The barbs 20 are preferably slightly inclined towards the web 18 of the clip, so that they are pulled further into engagement with the wall surface to counter any forces tending to pull the bead assembly 10 away from the corner.

Referring to Figures 5 and 6 of the drawings, in use, the corner bead assembly 10 can be fastened to an external corner of a brick wall by positioning the clips 16 at positions which correspond with respective courses 21 of mortar between adjacent rows 22 of bricks. Each clip 16 is attached to the corner bead 1 1 by snap-engaging the web 18 of the clip 16 into the channel 14 formed inside the nose 13 of the corner bead 11 . The hooked outer ends 19 of the arms 17 of the clips 16 engage over respective longitudinal side edges of the flanges 12 and, once fastened, it is not possible to separate the clips 16 from the corner bead 11 , although it is possible to adjust the positions of the clips 16 by sliding them longitudinally of the corner bead 11 .

When the corner bead assembly 10 is pressed against the corner, the barbs 20 on the clips 16 engage the mortar and secure the corner bead 11 thereto, as shown in Figure 6. The flanges 12 of the corner bead 11 are preferably arranged at an acute angle of slightly less than 90 degrees, so that the flanges 12 are deformed outwardly against a resilient bias when the corner bead assembly 10 is applied to the corner. This resilient bias serves to reinforce the engagement between the barbs 20 and the mortar 21. Once fastened, each wall can be plastered right up to the nose 13 of the corner bead assembly 10. The plaster penetrates through the slots and apertures 15 in the corner bead 11 , thereby forming a solid corner once the plaster has set.

In an alternative embodiment, the clips 16 may merely be fastened to the corner bead 11 at the outer ends of their respective arms. Alternatively, the clips 16 may comprise formations arranged to engage with the slots or apertures 15 in the corner bead 11 .

Referring to Figures 7 and 8 of the drawings, in an alternative embodiment of corner bead assembly 10, L-shaped clips 26 are similarly provided, each clip 26 comprising a pair of arms, each having an parallel inner and an outer portions 27,29 which are interconnected at their respective outer ends and are arranged to respectively lie in face-to-face registration with the front and rear surface of respective flanges 32 of the corner bead member. The inner ends of the inner portions 27 of the arms are interconnected by a curved corner formation 28, although a similar nose to the nose 18 of the first embodiment may be provided.

A plurality of barbs 30 are provided on the front face of each inner arm portion 27. Each clip 26 is formed of spring steel and can be attached to the corner bead 23 by pulling the outer portions 29 of the arms apart, so that the clip is w-shaped in configuration. The open arms of the clip can then be engaged over respective flanges 32 of the corner bead 23, so that the clip embraces the latter. Complementary inter-engaging formations (not shown) may be provided on the inner and/or outer portions 27,29 for engaging each other through apertures 25 formed in the flanges 32 of the corner bead 23.

The clips of the embodiment of Figures 7 and 8 are useful in circumstances where the angle bead 23 does not have a hollow nose with which the clip can be engaged.

It will be appreciated that a corner bead assembly in accordance with this invention can be quickly and easily applied to external corners formed between walls of a wide range of materials.