AU2002100111A4 - Expansion joint - Google Patents

Description

Regulation 3.2 Revised 2/98

AUSTRALIA

Patents Act, 1990

ORIGINAL

COMPLETE SPECIFICATION TO BE COMPLETED BY THE APPLICANT NAME OF APPLICANT ACTUAL INVENTORS ADDRESS FOR SERVICE INVENTION TITLE: DETAILS OF ASSOCIATED APPLICATION NO(S) Patrick John Primmer; Peter Joseph Shields andJohn Arthur Lowe Peter Joseph Shields John Arthur Lowe Patrick John Primmer Peter Maxwell Associates Level 6 Pitt Street SYDNEY NSW 2000 EXPANSION JOINT Nil The following statement is a full description of this invention including the best method of performing it known to me:m:\docs\20021 008\00281 6.do The present invention relates to a continuously extruded expansion joint for concrete slabs and, in particular, to an expansion joint that is formed of a resiliently deformable, thermoplastic material that can be extruded and cut to the desired length prior to installation.

Conventional expansion joints for concrete slabs are made of a bitumen/rubber mixture that, over time, becomes distorted or flattened, fractures and peels away, thus leaving an unsightly and uneven dark black line along the joint that often supports the growth of weeds in the cracks left between the bitumen/rubber mixture and the adjacent vertical edges of the slabs.

It is an object of the present invention to provide a continuously extruded expansion joint that overcomes, or at least substantially ameliorates, the disadvantages and shortcomings of the prior art.

According to the invention, there is provided a continuously extruded expansion joint cut to a desired length for concrete slabs comprising a body member having a constant cross section and being of a desired length, the body member being formed of a resiliently deformable, thermoplastic material, and having at least one wing member integrally formed with the body member and projecting sideways therefrom so that, when a concrete slab is poured adjacent to the side of the expansion joint from which the wing member projects, the wing member is entrapped within the concrete and prevents vertical movement of the expansion joint when the concrete slab is set.

Preferably, the body member is hollow and has opposed side walls and opposed upper and lower walls.

It is also preferred that the hollow body member has strength reinforcing members integrally connected between opposed side walls thereof.

12/02/2002 In order that the invention may be readily understood and put into practical effect, reference will now be made to the accompanying drawing (Fig 1) showing an end view of a continuously extruded expansion joint of constant cross section and desired length according to a preferred embodiment of the invention.

The continuously extruded expansion joint 10 of Fig 1 consists of a hollow body member 12, a pair of wing members 14, 16 and strength reinforcing members 18, 20, all integrally formed together through extrusion from a die. The expansion joint 10 is extruded in a continuous length with a constant cross-section, but is cut to a desired length to suit the length of the concrete slabs against which it is to be located.

The expansion joint 10 is formed of a resiliently deformable, thermoplastic material which, in this embodiment, is a recycled, high and low density polyethylene blend, although it may alternatively be a polypropylene blend. The thermoplastic material includes a UV stabilizer. The thermoplastic material should be resiliently deformable to the extent that it is non-fracturable under load and retains its flexibility over considerable time, the source of these desirable properties being clearly understood by persons skilled in the art. The expansion joint 10 also has release properties that make it suitable for use as formwork.

As shown in Fig 1, the expansion joint 10 has a flattened upper wall 22 adapted for location upwardly from the concrete slabs and a rounded lower wall 24 adapted to rest upon the excavated ground for the formwork. However, the walls 22, 24 may be inverted in their positions without substantially affecting the performance of the expansion joint.

There are a pair of notches 26, 28 in a continuous length formed into the opposed side walls below the lower reinforcing member 20. The notches 26, 12/02/2002 28 are also created in the extrusion process and provide weakened portions of the opposed side walls that allow the height of the expansion joint to be reduced by severing through the weakened portions. The reduced height of the expansion joint may be suitable for more shallow concrete slabs.

Various modifications may be made in details of design and construction without departing from the scope and ambit of the invention.

For instance, the expansion joint 10 may have only a single wing member and therefore be suitable for use when a concrete slab is to be poured against an existing solid wall or slab.

12/02/2002

Claims (3)

1. A continuously extruded expansion joint cut to a desired length for concrete slabs comprising a body member having a constant cross section and being of a desired length, the body member being formed of a resiliently deformable, thermoplastic material, and having at least one wing member integrally formed with the body member and projecting sideways therefrom so that, when a concrete slab is poured adjacent to the side of the expansion joint from which the wing member projects, the wing member is entrapped within the concrete and prevents vertical movement of the expansion joint when the concrete slab is set.

2. The expansion joint of claim 1 wherein the body member is hollow and has opposed side walls and opposed upper and lower walls.

3. The expansion joint of claim 2 wherein the hollow body member has strength reinforcing members integrally connected between opposed side walls thereof. Dated this 12th day of February 2002 Patrick John Primmer, Peter Joseph Shields and John Arthur Lower Patent Attorneys for the Applicant PETER MAXWELL ASSOCIATES 12/02/2002