AU4886202A - Improved mould liner - Google Patents

Description

1

AUSTRALIA

Patents Act 1990 Peter Stone COMPLETE SPECIFICATION Invention Title: Improved Mould Liner The invention is described in the following statement: Introduction to the Invention This invention relates to the manufacture of concrete paver blocks and the like and in particular relates to an improved method and apparatus for manufacturing such products.

Backgqround to the Invention The methods currently used for making paving blocks or other building elements from concrete mixes and other self setting, non fired compositions, has changed or developed little since time immemorial. In essence, a slurry of a self setting mixture is poured into a mould of suitable configuration; the mixture is allowed to set or cure ,the paver or block is removed from the mould, and when suitable cured, is ready for use. The process is not dissimilar to making a cake and indeed similar problems are encountered.

The typical mould used for making concrete pavers resembles a large cake tin and is generally made out of heavy duty steel and takes the form of a one piece mould. One of the problems encountered with the process is the removal of the set paver which tends to stick to the mould and requires considerable effort and skill to remove without causing damage. Whilst it is possible to construct a mould having removable sides or base, the additional cost and reduced stability of such moulds tend to negate any advantage in this approach. A more commonly used method involves the use of a release agent, which is applied to the mould prior to pouring, and which aids in the removal of the pavers when they have set in the mould.

Another problem with the current methods is the need to clean moulds after use to ensure a blemish free surface for pouring the next mould. The durable nature of the mixture used to make pavers and the like necessitates the use of costly release agents, discussed above, but the labour involved in cleaning and preparing moulds for use is still considerable and adds substantial labour cost to production.

Accordingly, the currently used techniques for manufacturing pavers and the like is costly, time and labour consuming, messy, produces a low quality finish and is generally inefficient.

Statement of the Invention In one aspect the invention provides a liner adapted for temporary placement on a mould said liner having a first face adapted to substantially conform to the mould interface and a second face forming the liner interface, wherein said liner is adapted to receive a mouldable mixture, which when set, can be readily removed from said mould and wherein said liner is readily separated from said set mixture.

The liner may be substantially rigid and self supporting and most preferably covers at least all of the mould interface.

The liner may extend beyond the mould interface and be made from a plastics material.

The liner may incorporate embossing on the liner interface so as to impart a pattern or configuration to the surface of the set mixture.

The liner may incorporate raised dividers to separate sections of the mould.

In another aspect the invention provides a method of manufacturing self setting paving blocks and the like comprising fitting a mould with a liner as previously described, filling lined mould with settable mixture, awaiting curing thereof and removing cured block from said mould.

The invention will now be described in greater detail with reference to Figures 1 to 4.

Figure 1 shows a cross-section of a typical mould incorporating the liner of the invention fitted to the mould.

Figure 2 shows an exploded view of a paver, liner and mould.

Figure 3 shows a cross section of a liner incorporating embossing.

Figure 4 shows another embodiment of the liner of the invention.

Referring firstly to Figure 1, the liner of the invention is shown as a cross section view fitted to the mould and filled with a suitable cement mixture for making paving stones. The liner 1, is formed of thin but rigid plastics material in a suitable shape to mirror or conform with the shape of the original mould 2.

The mould can take any form of currently available or modified moulds for manufacture of a wide range of building products, including, for example; paving blocks, bricks, garden edgings, gutter edgings, lawn edgings etc. As discussed in the preamble, the problem with such currently available moulds is the tendency of the cement mixture to adhere to the mould making release of the set paver difficult and requiring labour intensive cleaning operations and the use of expensive release agents to allow pavers to be removed from the mould.

The liner of the invention takes the form of a pre-shaped and dedicated product which would be manufactured to adapt and fit to the particular moulds currently available, or any other moulds that may be desired. The liner has a first face 3 which is adapted to substantially mirror the original mould interface 4, which would previously provide the interface for the finished surface of the paving products. The liner 1 is adapted to fit snugly against the mould interface within the confines of the mould, when the mould takes the form of that shown in Figure 1. The mould can of course, take various forms and maybe concave or convex, but whatever configuration the mould takes, the liner would be manufactured to mirror that shape. The liner 1 has a second face 5, forming the liner interface which represents the fresh interface presented to the concrete mixture 6 which will control and determine the dress surface of the paving products in question.

In the method of the invention, a standard mould 2 would be fitted with the disposable liner 1 and the mould/liner would then be filled with a suitable mixture 6 and allowed to set. Once the mixture has set, or substantially set so as to form a self supporting structure, it can be readily lifted or dropped from the mould with the liner readily separating from mould. The paver and liner combination can then be set to one side and stored for delivery in that format and when ready for use, the liner is simply removed from the paving block exposing the dress surface of the paving block in pristine and undamaged condition.

Referring now to Figure 2, an exploded view of the configuration of the mould 2 which is adapted to receive the similarly shaped liner 1, which in turn receives the mixture 6, giving rise to the final paver or building element.

The liner can be made of any suitable plastics material and is preferably of sufficient rigidity to maintain its own shape although it is not necessary to have substantial rigidity as the strength of the mould provides the necessary rigidity to retain the mixture and ensure the paver block or similar object is correctly formed. The liner is preferably at least as big as the mould and most preferably extends over the edges of the mould so as to ensure that the mould remains perfectly clean and ready for immediate re-use once the liner/paver is removed. The liner is preferably made from plastics material including polypropylene and/or polyvinylchloride. A suitable material may have the following specification:

ITEM

Thickness Tensile Strength (kg/mm 2 Elongation Dimensional Stability IZOD Impact Strength (kgcm/mm 2 VICAT Softening Temperature Transparency

V.C.M.

SPEC.

0.017 MD 4.0 (min) CD 4.0 (min) MD 80 (min) CD 100 (min) MD -6 (max) CD +1 (max) 11.0 (min) 75 (min) 85 (min) 1ppm (max) REMARK ASTMD-1 593 ASTMD-882 ASTMD-882 ASTMD-1204 (140 °C x 1 min/oil) ASTMD-256 ASTMD-1 525 ASTMD-1 003 ASTMD-3680 Referring now to Figure 3, the liner 1 may incorporate a series of embossing 7 formed on the liner interface 5. The embossings provide a ready means of forming a pattern or configuration for the paving blocks formed therein and the embossings can either take a positive or negative relief dependent on requirements. In the case of negative reliefing, the liner 1 would be formed of suitably thick material, at least in the base region 8 thereof, so as to allow suitably deep embossing. The embossing may take the form of ridges or separating sections, so as to provide the impression of multiple pavers within one unit and may of course take any desired shape or configuration as is required.

Referring now to Figure 4 an alternative embodiment of the invention is shown with the liner 1 taking a circular formation for preparation of round pavers. The base region 8 incorporates embossing 7 so as to provide attractively patterned paving stones.

In use, the liner of the invention provides an economical accessory for use with currently available moulds and provides a means of rapidly producing paving stones greatly reducing the time required to release paving blocks from moulds, virtually eliminating clean-up time and allowing moulds to be used on a rotational basis on a highly economical fashion. The paving block/liner, once removed from the mould can remain together such that the pavers are provided with a ready protection of the dress surfaces and can therefore be stored with minimal or no damage and arrive at a building site in pristine condition. Once the pavers are ready to be used, the liners are simply removed, thereby providing clean, fresh and undamaged dress surfaces for use on site. A further advantage of the invention is the ability of the liner to provide a highly polished and glazed surface to paving stones by virtue of the cement mixtures interaction with the smooth surface provided by the liner material.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Dated this twentieth day of June 2002 Peter Stone Patent Attorneys for the Applicant: F B RICE CO

Claims (9)

1. A liner adapted for temporary placement on a mould said liner having a first face adapted to substantially conform to the mould interface and a second face forming the liner interface wherein said liner is adapted to receive a mouldable mixture, which when set, can be readily removed from said mould and wherein said liner is readily separated from said mixture.

2. A liner according to claim 1, which is substantially rigid and self- supporting.

3. A liner according to claim 1 or 2, wherein said liner covers at least all of the mould interface.

4. A liner according to claim 3 wherein said liner extends beyond the mould interface and is made for a plastics material.

A liner according to any one of claims 1 to 4 which incorporates embossing on the liner surface so as to impart a pattern or configuration to the surface of the set mixture.

6. A liner according to any one of claims 1 to 5 which incorporates raised dividers to separate sections of the mould.

7. A method of manufacturing self setting paving blocks and the like comprising fitting a mould with a liner according to any one of claims 1 to 6, filling said lined mould with settable mixture, awaiting curing thereof and removing cured block from said mould.

8. A liner according to any one of claims 1 to 6 substantially as hereinbefore described with reference to Figures 1 to 4.

9. A method according to claim 7 substantially as hereinbefore described with reference to Figures 1 to 4.