In order to shape the plaster at a convex corner of two adjoining walls, builders use a trowel having a concave working surface. When on the other hand the plaster at a concave corner between two adjoining walls is to be shaped, a trowel having a concave working surface is used. To date builders have used two separate trowels for this function, i. e. a corner trowel and a profile trowel.

It would therefore be beneficial if a single trowel could be provided which could perform both these functions.

It is an object of the present invention to address the above problem.

SUMMARY OF THE INVENTION According to the present invention there is provided a building accessory for plastering and optionally for jointing, the accessory including: a radiussed angle-profile concave working surface for plastering and shaping an outer corner defined at ah intersection between two walls of a building structure by moving the working surface along and in contact with the walls at the corner; a radiussed angle-profile convex working surface for plastering and shaping an inner corner defined at an intersection between two walls of a building structure by moving the working surface along and in contact with the walls at the corner; a mounting arrangement located between the respective radii of the concave working surface and the convex working surface; and a griping member connected to the mounting arrangement, the concave and convex working surfaces facing oppositely outwardly away from each other and the gripping member being movable between two operative positions in which it is respectively lockable, namely an outer position, radially outward of the working surfaces, for gripping by a user during use of the concave working surface and an inner position, radially inward of working surfaces, for gripping by a user during use of the convex working surface.

By radiussed is meant that the respective working surfaces are curved about corners which are not sharp 90° corners but are relatively smoothly curved and rounded about respective radii, being primarily suitable respectively for plastering and shaping outer or convex corners of 90° between two walls, and for plastering and shaping inner or concave corners of 90° between two walls, although convex corners of less than 90° and concave corners of more than 90° can naturally be dealt with.

The concave and convex working surfaces may furthermore have smooth rounded peripheral edges such that, in use, the edges of the working surfaces are inhibited from digging into the plaster of walls being plastered.

The building accessory may be made from steel, nickel-or chromium-plated steel, aluminium, brass, cast iron, polymeric plastics or other suitable material.

Further, the accessory may be moulded from any one of these materials or other suitable materials. Instead, the accessory may be machined from a solid block of any of these materials or other suitable materials. As a further alternative, the accessory may be cast or extruded.

The mounting arrangement may be located to extend between the concave working surface and the convex working surface in a position such that, in use, the mounting arrangement is out of the way of the walls being plastered. The mounting arrangement may define a passage therein for receiving the gripping member, the passage having a wall profiled for receiving and engaging the gripping member. The passage of the mounting arrangement may extend along the full length of the corner of each working surface, from one end thereof to an opposed end thereof. Thus, the mounting arrangement may comprise a tube having a wall of a circular, or square, rectangular or other suitable cross-section, extending along and between said corners of the working surfaces. The gripping member will typically comprise a handle for facilitating gripping of the accessory, and an engaging member connected to the mounting arrangement.

The gripping member may include a kinked or cranked portion between the engaging member and the handle. Thus, in use, the end of the kink or cranked portion adjacent the gripping member may abut against the mounting arrangement or against an edge of the working surface adjacent the mounting arrangement, thereby facilitating locking in position of the gripping member.

The engaging member may be shaped so as to be snugly received in the passage in the mounting arrangement with a sliding working clearance.

Further, the engaging member may have a shape profiled to cooperate with a profiled inner wall of the passage in the mounting arrangement, to lock the engaging member in position against rotation in the passage. In addition thereto, the engaging member may be shaped and dimensioned to provide a jointing tool for jointing between courses of bricks, the engaging member being removable from the mounting arrangement for this purpose. Instead, the gripping member may be more or less permanently connected to the working arrangement, the handle comprising a removable grip frictionally held on a core, the core being shaped and sized to form a jointing tool.

The handle may project longitudinally, relative to their corners, away from the concave working surface and convex working surface; or it may be curved to overhang said surfaces. In one embodiment the gripping member may be held captive by its engagement with the mounting arrangement, being rotatable relative thereto, for example by rotation thereof between said outer position suitable for using the concave working surface and said inner position suitable for using the convex working surface, in which positions it is releasably lockable against said rotation.

In a particular embodiment of the invention, the concave working surface may be provided by a curved inner member having a radiussed angle-profile, and the convex working surface may similarly be provided by a curved outer member having a radiussed angle-profile. Thus, in other words, according to the invention there is provided a building accessory for plastering and optionally for jointing, which accessory includes: a curved inner member having a radiussed angle-profile concave working surface for plastering and shaping an outer corner defined at an intersection between two walls of a building structure by moving the working surface along and in contact with the walls at the corner; a curved outer member having a radiussed angle-profile convex working surface for plastering and shaping an inner corner defined at an intersection between two walls of a building structure by moving the working surface along and in contact with the walls at the corner; a mounting arrangement located between the inner member and the outer member, the mounting arrangement connecting the inner member to the outer member so that the inner member nests in the outer member in desired spaced relationship thereto; and a gripping member connected to the mounting arrangement and lockable in position, for gripping by a user of the accessory when in use.

As indicated above, the inner member and outer member may be made from steel, nickel-or chromium-plated steel, aluminium, brass, cast iron, polymeric plastics or other suitable material. Further, the inner member and the outer member may be moulded from any one of these materials or other suitable materials. Furthermore, the inner member and the outer member may be cast or moulded together with the mounting arrangement or instead may be extruded together with the mounting arrangement.

The working surfaces may be provided by linings or inserts on the inner and outer surfaces of the inner member and outer member respectively.

Each lining or insert may be made from a sheet or plate of hard-wearing or wear-resistant material, such as a metal. Thus, each lining or insert may be a sheet or plate of steel, more specifically it may be a sheet of stainless steel.

Instead, each lining or insert may be a sheet of nickel-or chromium-plated steel, aluminium, brass, or cast iron, the remainder of the member in question being of plastics material or any other suitable material.

The mounting arrangement may extend between the inner member and the outer member to interconnect them at positions spaced from the peripheral edges of their working surfaces, such that, in use, the mounting arrangement is out of the way of any corners of walls being plastered. The mounting arrangement may define a passage therein for receiving the gripping member.

As indicated above the passage of the mounting arrangement may extend along the full length of the corner of each working surface, from one end thereof to an opposed end thereof. The passage may have a wall profiled for receiving and engaging with the gripping member. Thus, the mounting arrangement may comprise a tube having a wall of a circular, or square, rectangular or other suitable cross-section, extending along and between said corners of the working surfaces.

The handle may project longitudinally, relative to their corners, away from the inner member and outer member; or it may be curved to overhang said members. In one embodiment the gripping member may be held captive by its engagement with the mounting arrangement, being rotatable relative thereto, for example by rotation thereof between said outer positions suitable for using the inner member and said inner position suitable for using the outer member, in which positions it is releasably lockable against said rotation.

Instead, the concave and convex working surfaces may be provided by a solid unitary or monolithic radiussed angle-profile block, having a substantial thickness between the working surface, the mounting arrangement being provided, for example, as a passage, in the solid material of the block. A yet further possibility is a hollow block, in which, for example the inner and outer members described above have their peripheral edges opposed and in register and interconnected by edge walls, the mounting arrangement being provided in the hollow interior of the block.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described further, by way of example only, with reference to the following drawings, in which: Figure 1 is a perspective view of a building accessory for plastering and jointing in accordance with the invention; Figure 2 is another perspective view of the building accessory of Figure 1, with a gripping member of the accessory in a different position; Figure 3 is a perspective view of another embodiment of a building accessory for plastering and jointing in accordance with the invention; Figure 4 is a sectional side elevation of the building accessory of Figure 3; Figure 5 is another perspective view of the building accessory of Figure 3, with a gripping member of the accessory in a different position ; Figure 6 is a further perspective view of a gripping member of the accessory of Figure 1; Figure 7 is a further perspective view of a gripping member of the accessory of Figure 3; Figure 8 is a perspective view of a third embodiment of a building accessory according to the invention; and Figure 9 is a cross-sectional view of the building accessory at the line A-A in Figure 8.

DESCRIPTION OF PREFERRED EMBODIMENTS In the drawings, like reference numerals indicate like parts, unless otherwise indicated.

In Figures 1 and 2 of the drawings, the reference numeral 10 generally indicates a building accessory for plastering and jointing in accordance with the invention. The accessory 10 includes a curved inner member 12, a curved outer member 14, a mounting arrangement 16 connecting the inner member 12 to the outer member 14, and a gripping member 18.

The inner member 12 is a short length of radiussed angle-profile iron providing a shaped steel body having an inner surface 20 and an outer surface 22. A radiussed angle-profile smooth concave working surface 24 is defined by the inner surface 20 of the inner member 12. Thus, the working surface 24 includes two broadly planar parts between which a roughly radiussed right- angle concave shaping corner 26 is defined.

The outer member 14 is similarly a short length of radiussed angle-profile iron providing a shaped steel body having an outer surface 28 and an inner surface 30. A radiussed angle-profile convex smooth working surface 32 is defined by the outer surface 28 of the outer member 14. Thus, the working surface 32 includes two broadly planar parts between which a radiussed roughly right- angle convex shaping corner 34 is defined.

The mounting arrangement 16 is in the form of a hollow steel tube having a wall of square cross-section. A square passage is defined in the steel tube 16 and extends from one end of the tube 16 to an opposed opposite end of the tube 16. The inner member 12 is welded to a side wall of the tube of the mounting arrangement 16 on its outer surface 22, along an edge defined on its outer surface 22 at its convex corner opposed to its concave corner 26. The outer member 14 is welded to two edges of one of the side walls of the tube 16 of the mounting arrangement on opposite sides of its concave corner opposed to its convex corner 34, such that the inner member 12 nests in the outer member 14 in spaced more or less parallel relationship thereto with the convex corner 34 of the outer member 14 being parallel to and in alignment with the concave corner 26 of the inner member 12.

The gripping member 18 includes an engaging member 42 and a handle member 44. The engaging member 42 is in the form of an elongate square cross-section steel bar or rod having a screw-threaded hole 46 at one end thereof which receives a screw on a bolt 48 which releasably locks in position the gripping member 18 on the mounting arrangement 16. The engaging member 42 is dimensioned such that it is snugly received in the passage in the tube 16 of the mounting arrangement, with a sliding working clearance.

The gripping member 18 has a kinked or cranked portion 50 at its midsection.

The portion 50 ensures that, in an operative condition, the handle member 44 is out of the way of corners of any walls being plastered. The handle member 44 comprises a wooden handle or grip 40 of the type generally used with conventional trowels. The wooden handle 40 is fitted on to the handle member 44 at the end of the gripping member 18 remote from the engaging member 42.

In use, the accessory 10 as shown in Figure 1 is gripped with the aid of the wooden handle 40, by a user. The inner surface 20 of the inner member 12 is then brought into contact with plaster at a convex 90° corner on two walls of a building structure (not shown) to be plastered. The working surface 24 contacts said walls, with the concave shaping corner 26 of the inner member 12, being sliding engaged with a convex outer corner formed between the two walls. Thus with the handle member 44 in a radially outer position projecting axially and radially outwardly away from the inner member 12 and outer member 14, the gripping member 18 is held by the user, and the inner working surface 24 of the inner member 12 is moved along and in contact with the walls at the outer corner of the building structure, thereby shaping the outer corner between the two walls.

When it is desired to shape an inner corner of a building structure, the engaging member 42 is released from the mounting arrangement by releasing the bolt 48 from the screw threaded hole 46 of the engaging member 42, the gripping member is then, when so released, rotated by 180° to a radially inner position suitable for using the outer member 14, as shown in Figure 2, and then reinserted and locked in position prior to use. In its locked positions the gripping member 18 in the tube 16 is held in tension by the bolt 48 and the kinked portion 50 abutting against the members 12 and 14 respectively at opposite ends of the tube 16.

Referring to Figures 3 and 4 of the drawings, reference numeral 60 generally refers to another embodiment of the building accessory for plastering and jointing in accordance with the invention.

The accessory 60 is generally similar to that shown in Figures 1 and 2. As can be seen in Figure 3, the members 12,14 of the accessory 60 are longer than those of the accessory 10. However, the gripping member 18 has an engaging member 42 similar to that of Figures 1 and 2. The handle member 62 is however curved to overhang the outer member 14 (Figures 3 and 4) or the inner member 12 (Figure 5). Thus, in use, when plastering an outside corner between two walls of a building structure, the handle member 62 is positioned such that it overhangs the outer member 14. When it is desired to use the accessory 60 to plaster the inside corner between two walls of a building structure, the gripping member 18 is released from the mounting arrangement 16, rotated about an angle of 180° and re-inserted into the passage 36 and locked into position with the handle 62 overhanging the inner member 12 (Figure 5).

The gripping members 18 as used in the two embodiments are shown respectively in Figures 6 and 7. It will be appreciated that a number of variations of the gripping member 18 is possible.

Each gripping member 18 is shaped to provide a jointing tool for jointing between corners of bricks. Thus the engaging member 42 may in particular by used as a jointing tool after removal from the tube 16, or the metal core on which the handle or grip 40 is received can be used for this purpose, after removal therefrom of the handle 40.

It will be appreciated that the opposed or registering edges of the members 12 and 14 can be interconnected by edge walls to close off a hollow interior of the accessory 10 in which the arrangement 16 is provided, this hollow interior may be filled by solid material, so that the accessory 10 is a solid, monolithic radiused angle-profile block, in which the arrangement 16 can be provided, for example, by a passage of suitable cross-section between the corners 26 and 34, which receives the engaging member 42 of the gripping member 18.

Figure 8 and Figure 9 show a third embodiment of a building accessory 70 having a unitary block 72. The block 72 includes a concave working surface 24 and a convex working surface 32. The building accessory 70 further includes a mounting arrangement, not visible in Figure 8, which allows the gripping member 18 to pivot relative to the two working surfaces. In this embodiment the mounting arrangement 16 includes a passage 74 which is defined by the block 72. The engaging member 42 of the handle member 18 is held in the passage 74 as shown.

The mounting arrangement 16 further comprises a lock 76 which is attached to the engaging member 42 and which abuts the underside of the block 72 in a locking position. A screw 78 and a washer 80 secure a biasing means, here a resilient helical spring 82, to the top portion of the engaging member 42. As shown the screw 78 is screwed into the top end of the engaging member 42.

The spring 82 rests on two shoulders 84 in the passage 74.

To rotate the gripping member 18 relative to the block 72 in order to move it, say, from the inner position to the outer position, the gripping member 18 is pulled downwards by a user whereby the engaging member 42 slides down the passage 74 and the lock 76 is removed from its abutting position with the block 72. The downward movement of the engaging member causes the spring 82 to become compressed between the washer 80 and the shoulders 84. The block 72 can now be rotated. Once the rotation has been completed, the block is located in the inner position and the gripping member can be released by the user. Once the gripping member 18 is released by the user the resilience in the spring 82 causes it to return to its original position. As a consequence the lock 76 returned to its abutting position with the block 72, thereby locking the block 72 relative to gripping member 18.

The building accessory of the invention as illustrated with reference to the various embodiments offers the advantage that it can be used to plaster outside and inner corners between walls in a building structure. Further, the gripping members 18 as illustrated also serves as an independent jointing tool for jointing between courses of bricks in building structures. The building accessory 10 has a further advantage in that it could be produced and sold at a lower price than two separate corner or profile trowels.