NZ758472B2 - Formwork system and method - Google Patents

Abstract

traditional slab on ground is generally constructed by one of two methods, namely a raft slab or alternatively a waffle pod slab. Each of these methods presents advantages and disadvantages. Whilst the existing formwork system for constructing rebate toes are widely used, it suffers from several inherent drawbacks. In particular, timber boards are heavy and they tend to become heavier when wet due to the timber absorbing water. A further drawback is that timber boards are nailed together during assembly of the formwork. As such, the timber boards require a large amount of effort to disassemble and de nail. The nails are then discarded and not re-used. When using heavy timber boards, the weight is known to pose problems with respect to operational health and safety (OHS) on account of heavy lifting issues, and a significant risk of injury. A formwork system (100) includes a rebate board (105) having a generally L shaped profile in end view, the rebate board having a first arm (110) and a second arm (120), the first and second arms (120) being angled at about 90 degrees relative to each other, the second arm being securable to an upper portion of a formwork bottom board (200). The system includes a brace (400) having a first engagement formation (410) configured to engage with the first arm, and a second engagement formation (435) configured to engage with a peg (220) or another fixed member. A generally horizontal underside surface of the second arm and a contiguous generally vertical surface of the first arm are configured to retain setting concrete to define a rebate in the concrete slab. The second arm includes a longitudinally extending stopper configured to abut against the bottom board. The stopper has a triangular cross sectional profiled having a flat surface adapted to abut against the bottom board.

Claims (14)

Claims:

1. A temporary formwork system for forming concrete slabs comprising: a rebate board having a generally L shaped profile in end view, the rebate board having a first arm and a second arm, the first and second arms being angled at about 90 degrees relative to each other, the second arm being securable to an upper portion of a formwork bottom board; and a brace having a first engagement formation configured to engage with the first arm, and a second engagement formation configured to engage with a peg or other fixed member, wherein a generally horizontal underside surface of the second arm and a contiguous generally vertical surface of the first arm are configured to retain setting concrete to define a rebate in the concrete slab, wherein the second arm includes a longitudinally extending stopper configured to abut against the bottom board, and wherein the stopper has a triangular cross sectional profile having a flat surface adapted to abut against the bottom board.

2. The formwork system of claim 1, wherein the first engagement formation includes two longitudinally extending ribs defining a channel configured to abut against and engage opposing sides of the first arm.

3. The formwork system of any one of the preceding claims, wherein the second engagement formation includes a plurality of holes separated from each other along a longitudinal axis of the brace.

4. The formwork system of any one of the preceding claims, wherein the second arm includes a plurality of longitudinally separated air and/or inspection holes.

5. The formwork system of any one of the preceding claims, wherein each rebate board includes a third engagement formation located at one end of the rebate board and a corresponding fourth engagement formation located at an opposing end of the rebate board, the third and fourth engagement formations permitting like rebate boards to be connected end to end.

6. The formwork system of claim 5, wherein the third and fourth engagement formations include male and/or female elements located on each end of the first and second arms of the rebate board.

7. The formwork system of claim 6, wherein the second arm includes a male formation at a first end and a corresponding female formation at an opposing second end, further where the first arm includes a first hook portion at the first end and a corresponding second hook portion at the second end.

8. The formwork system of claim 6, wherein the first arm includes a male formation at a first end and a corresponding female formation at an opposing second end, further where the second arm includes a first hook portion at the first end and a corresponding second hook portion at the second end.

9. The formwork system of any one of the preceding claims, further comprising a H-connector having a generally H-shaped cross-sectional profile, the H-connector defining two channels each channel configured to receive a longitudinal edge portion of the bottom board, or the first arm.

10. The formwork system of claim 9, wherein the H-connector includes a lug having one or more securement holes for engaging with a support member.

11. The formwork system of any one of the preceding claims, wherein the brace is fabricated in a two part arrangement having a stem which is separable relative to a head.

12. The formwork system of claim 11, wherein the stem includes a trapezoidal projection adapted to be received by a trapezoidal slot formed in the head.

13. The formwork system of any one of the preceding claims, wherein the rebate board and the brace are fabricated from a polymer.

14. The formwork system of any one of the preceding claims, wherein the brace includes upper and lower longitudinally extending stiffening ribs.