GB2224234A

GB2224234A - A plastics mould, openable at an integral hinge means

Info

Publication number: GB2224234A
Application number: GB8921493A
Authority: GB
Inventors: Robert Armstrong; Stuart Armstrong
Original assignee: ARMSTRONG
Current assignee: ARMSTRONG
Priority date: 1988-09-22
Filing date: 1989-09-22
Publication date: 1990-05-02
Anticipated expiration: 2009-09-22
Also published as: GB2224234B; GB2254582A; GB2254582B; GB8822325D0; GB8921493D0; GB9210793D0

Abstract

According to one aspect, an open topped one-piece plastics mould (1) for moulding a concrete block, is preferably of polypropylene, and is pivotally openable and closeable along a notch (6) extending downwardly along a mould side (4) from the top of the mould to the pivotable apex of the notch, whereby closure of the notch produces a mould cavity of the shape of the moulded article to be produced, and the pivotal separation of the sides of the notch (6) to open the mould, is effected by the resiliency of the plastics of the mould wall. A notch may be provided along each corner of a mould (Fig. 4), for pivot a opening of opposed mould sides. According to another aspect, a plastics mould of a similar sheet-like plastics, comprises a base (105) and a pair of side walls (102) which are pivotal at a junction (103) relative to the base (105) so as to become generally perpendicular thereto to define a mould cavity, at least one of said walls being preformed (104) such that the mould cavity has an underhang section. The moulds may be seated within a mould box, to be retained in their closed moulding position. <IMAGE>

Description

MOULDS This invention relates to moulds, and more particularly to moulds for producing articles of concrete or other hydraulic materials.

A first aspect of the invention relates to moulds which facilitate the release of moulded articles therefrom.

If a one piece, open-topped plastics mould is used for the production of concrete blocks then it has been necessary heretofore for two opposed walls of the mould to be inclined downwardly (i.e. in the direction of mould depth) slightly toward each other. This ensures that the finished block may be removed easily from the mould but the block will have correspondingly inclined opposed side faces which may not be satisfactory for some purposes. If a block with parallel opposed faces is required then it has been necessary to use a mould formed of separable mould components. After curing of the concrete, the mould components must be separated from each other to release the block. However such moulds are more expensive to produce than one piece plastics moulds and the assembly and separation of the mould component represent time consuming steps.

It is an object of the first aspect of the invention to obviate or mitigate this disadvantage.

According to the first aspect of the present invention there is provided an open topped one-piece plastics mould, preferably of polypropylene, with an openable and closeable notch extending downwardly from the top of the mould in a side thereof whereby closure of the notch produces a mould cavity of the desired shape of the article to be produced and opening of the notch facilitates removal of the article from the mould.

The mould may have a single notch but it is preferred that the mould is provided with notches at opposite sides thereof so as to separate the top of the mould into two or sections.

Preferably the or each notch of the mould is urged open by the resilience of the plastics material.

In use, the separate sections of the mould are closed together and held in this closed position. The mould is then filled with concrete (or other hydraulic material) which is then cured. The moulded article may then be separated from the mould by causing the separate sections of the mould to open away from each other so as to facilitate removal of the article from the mould.

The notch or notches may extend partly or completely down the walls of the mould. The or each notch may for example by of a V-shaped configuration extending down from the respective upper edge of the mould. Alternatively, the notch may extend downwards from the respective upper edge of the mould and then deviate in direction and terminate in a lower V-shaped section. In this latter arrangement, the notch may overall be of "dog leg" configuration.

The notches may be provided one in each of two opposed sides of the mould. Alternatively, each of two opposed sides may have two notches.

A second aspect of the invention relates to the moulding of articles with a section which underhangs a portion of the mould. A particular example is an I-section concrete post such as used for fencing. Heretofore such posts have been produced as metal moulds having channel section sides each articulated to the base of the mould. After moulding and curing, the sides are pivoted away from the post so that it may be removed. However, such moulds are prone to leakage along the articulated joints and moreover are expensive and time consuming to use.

It is therefore an objection of the second aspect of the invention to obviate or mitigate this disadvantage.

According to the second aspect of the invention there is provided a plastics mould of a sheet-like material having a base and a pair of side walls which are pivotal relative to the base so as to become generally perpendicular thereto to define a mould cavity, at least one of said walls being preformed such that the mould cavity has an underhang section.

Such a mould, which is preferably of polypropylene is used in a method in which the sheet like mould is folded within a former to define a mould cavity with its section maintained by the former, casting hydraulic material (e.g.

concrete) into the mould cavity and subsequently moving the side walls away from the solid article.

The invention will be further described by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a first embodiment of mould in accordance with the first aspect of the invention; Fig. 2 shows the "opening" of the mould of Fig. 1; Fig. 3 shows the mould of Fig. 1 being filled with concrete; Fig. 4 is a perspective view of a second embodiment of mould in accordance with the first aspect of the invention; Fig. 5 illustrates a mould in accordance with the second aspect of the invention being inserted into a former; and Fig. 6 illustrates the moulding of a post using the mould of Fig. 5.

Fig. 1 shows an open-topped mould 1 for producing a concrete block with a patterned face as determined by the surface feature on the mould floor 2. The mould 1 is of polypropylene and has a surrounding lip 3.

On two opposed walls 4 and 5, the lip 3 is downwardly turned as shown to define a V-shaped flange 6 which bounds a respective notch 7 formed in the wall and extending substantially down the height thereof. The mould 1 is such that, without any force being applied to the mould 1, the notch 7 opens by virtue of the resilience of the polypropylene. Thus walls 8 and 9 of the mould are inclined downwardly towards each other (see Fig. 2). However when walls 8 and 9 are urged towards each other, the notches 7 -close such that walls 8 and 9 are parallel. It is in this configuration that the mould 1 is used for producing a concrete block. The mould may be seated in a box (not shown) to maintain this configuration during moulding. As shown in Fig. 3, the mould is filled with concrete 10 in the conventional manner which is then allowed to cure.

Subsequently the mould is manipulated so that notches 7 open thus separating walls 8 and 9 from the associated faces of the block which may now easily be removed from the mould.

For mass production of the blocks, a plurality of the moulds 1 may be supported in a lattice like structure each "compartment" of which supports a mould 1 with its notches 7 closed. After the concrete has cured, the moulds are removed from the lattice and opened as aforesaid.

Fig. 4 illustrates a rectangular mould 41 in which two notches 42 are formed in each of the two opposed longitudinal sides 43 of the mould, the notches 42 in any one side 43 being provided towards the opposite ends thereof. Each notch 40 is of a generally "dog leg" configuration with an upper section extending downwardly from the respective top edge of the mould and a lower V-shaped section pointing towards, and extending to, the adjacent lower widthwise edge 44. As in the case of the mould illustrated in Fig. 1, the mould 40 is provided with a bounding flange 45 which also bounds the notches 42.

The aforementioned lower widthwise edges 44 act as hinges whereby the resilience of the plastics material normally urges the notches open so that the mould is divided into separate sections as shown.

As in the case of the mould of Fig. 1, the mould 40 may be seated in a box (not shown) so as to maintain the mould closed for a moulding operation. If desired, wooden strips 46 may be provided as shown beneath the bounding flanges 45 for supporting the mould around the top edge of the box.

The second aspect of the invention is illustrated in Figs. 5 and 6 for the formation of an I-section beam. In Fig.

5, there is shown a polypropylene mould 100 which has a base 101 and integral side walls 102 which are foldable towards each other so as to be perpendicular to the base along score lines 103 or the like. Each side wall 102 is preformed with a channel section 104 opposed to the corresponding section of the other side wall whereby the mould may be folded (along lines 103) to define an I-section mould cavity which has two underhang sections 105. The mould 100 may be formed by injection moulding.

In use, the mould 100 is introduced into a rectangular U-section former 106 so that the mould is "bent" into, and retained in the aforementioned I-section, as clearly illustrated in Fig. 6.

Although not illustrated in the drawing, it is preferred that I-section bungs (e.g. of rubber) be located at each end of the I-section defined by the mould.

Concrete may now be poured into the mould. After curing, the assembly of mould 100 and beam 107 may be lifted from the former 106. Mould 100 may now be easily stripped (by folding) away from the beam 107.

Modifications may be made to the embodiment of Figs. 5 and 6 for producing other moulded articles with a section which underhangs a portion of the mould. Thus, for example, the mould cavity may be of inverted T-section of L-section.

Claims

1. An open topped one-piece plastics mould, preferably of polypropylene, with an openable and closeable notch extending downwardly from the top of the mould in a side thereof whereby closure of the notch produces a mould cavity of the desired shape of the article to be produced and opening of the notch facilitates removal of the article from the mould.

2. A mould as claimed in claim 1, provided with notches at opposite sides of the mould so as to separate the top of the mould into sections.

3. A mould as claimed in claim 1 or 2, wherein the or each notch is urged open by the resilience of the plastics material.

4. Mould as claimed in claim 2, wherein said opposed sides are each provided with one notch.

5. Mould as claimed in any one of claims 1 to 3, wherein said opposed sides are each provided with two notches.

6. A mould as claimed in any one of claims 1 to 3, wherein the or at least some of the notches are V-shaped.

7. A mould as claimed in any one of claims 1 to 5 wherein the or at least some of the notches extend downwards from the respective upper edge of the mould, then deviate in direction, and terminate in a lower V-shaped section.

8. A mould as claimed in claim 7, wherein two opposed sides of the moulds are each provided with two of the notches, and the V-section of each notch points towards, and extends to, an adjacent lower edge of the mould cavity.

9. Mould as claimed in any one of claims 1 to 8, wherein the or at least some of the notches are bounded by a flange external of the mould cavity.

10. Mould as claimed in any one of claims 1 to 9, which is of polypropylene.

11. Method of producing a moulded article comprising retaining a mould as claimed in any one of claims 1 to 10, in a position in which the notches are closed, introducing hydraulic material (e.g. concrete) into the mould cavity, curing the hydraulic material, causing the notches to open, and removing the article from the mould.

12. A mould substantially as hereinbefore described with reference to Figs. 1 to 3 or Fig. 4 of the accompanying drawings.

13. A method of producing a moulded article substantially as hereinbefore described with reference to Figs. 1 to 3 or Fig. 4 of the accompanying drawings.

14. A plastics mould of a sheet-like material having a base and a pair of side walls which are pivotal relative to the base so as to become generally perpendicular thereto to define a mould cavity, at least one of said walls being preformed such that the mould cavity has an underhang section.

15. A mould as claimed in claim 14, wherein each side wall is so preformed.

16. A mould as claimed in claim 14 or 15, wherein the wall (or walls) is (or are) preformed with a channel section.

17. A mould as claimed in any one of claims 14 to 16, which has been preformed with fold lines between each side wall and the base.

18. A mould as claimed in claim 14, wherein the mould cavity is of I-section.

19. A mould as claimed in claim 14, wherein the mould cavity is of inverted T-section.

20. A mould as claimed in any of claims 14 to 19 which is of polypropylene.

21. A method of producing a moulded article comprising providing a mould as claimed in any one of claims 14 to 20 comprising retaining the side walls in the upright position, introducing hydraulic material (e.g. concrete) into the mould cavity, curing the material, and moving the side walls away from the moulded article to release same.

22. A mould substantially as hereinbefore described with reference to Figs. 5 and 6 of the accompanying drawings.

23. A method of producing a moulded article substantially as hereinbefore described with reference to Figs. 5 and 6 of the accompanying drawings.