GB2050920A - A mould for casting concrete shutter blocks - Google Patents

Abstract

A readily portable concrete shutter block mould (1) for casting a block having two parallel panels interconnected by rigid ties, comprises two mould portions (2, 3), which are releasably interconnected in a vertical plane (X-X) corresponding to a diagonal of the mould (1), and has removable upper (11/12) and lower horizontal mould floors, the upper mould floor having a pair of apertures (13) for receiving and supporting the respective rigid ties which interconnect the panels of the block. The mould is provided with internal contouring for shaping tongues (14) and grooves (15) on the panel edges. <IMAGE>

Description

SPECIFICATION A mould for casting concrete shutter blocks The present invention relates to a mould for casting concrete shutter blocks.

More particularly, the invention is concerned with a mould for casting individually concrete shutter blocks of the type comprising two four-sided walls of concrete rigidly interconnected in a parallel spacedapart relationship by at least two rigid ties, the ends of which are embedded in the walls, each of the walls having two adjoining longitudinally tongued edges and two correspondingly grooved edges which permit neighbouring blocks to be interlocked when erected. Blocks of this type, and a method for their manufacture, are described in Patent Application No. 27432175 Serial No. 1549859 by the same applicants.

Shutter blocks of the aforesaid type are used in the erection of concrete walls, embankments, culverts and the like to provide a self-supporting, permanent formwork defining a mould cavity into which premixed concrete is subsequently poured. The formwork so-formed is erected quickly and accurately, since the tongue-and-groove interlocking eliminates the need for the mortar joints or braces used in previous formworks. Moreover, once erected, the blocks are interlocked and remain fixed in position during the pouring and subsequent curing of the infilling concrete.

The method disclosed in the earlier Application No. 27432/75 Serial No 1549859 specified the use of a gang mould for producing batches of the blocks.

One example of such a gang mould comprises a plurality of pallets forming lower mould floors, each pallet being provided with stop walls which retain transversely extending vertical mould side walls separating the pallets and have ledges for deck plates forming upper mould floors. The deck plates are provided with apertures for the insertion and retention of pre-cast concrete ties during the casting of a block wall in each of the lower and upper moulds respectively. Horizontal rails are provided to brace the pallets, and along which the individual pallets are advanced once the moulds are filled with concrete. Each pallet reaches the end of the rails when the concrete has cured, enabling removal of the pallet and breaking of the mould to leave a shutter block ready for use.

A disadvantage of this method is that the gang mould takes up a large flat area and has to be precisely set-up prior to casting the blocks, since the rails must be accurately parallel and horizontal in order to brace the pallets and allow accurately dimensioned blocks to be cast. This precise settingup requires skilled labour and obviously militates against the use of the mould for on-site casting operations.

The object of the present invention is to provide a mould for blocks of the aforesaid type which is simple to set-up and operate, and which is readily portable.

According to the present invention there is provided a mould for casting shutter blocks of the aforesaid type, in which the mould comprises two rigid portions which are releasably interconnected along co-operating edges in a vertical plane corres ponging to a diagonal of the mould, to render the mould self-supporting, the mould having an upper mould floor, which is horizontal in use of the mould, and adjacent internal tongues and grooves for moulding one wall of the shutter block, and a lower mould floor with adjacent internal tongues and grooves for moulding the other wall of the shutter block, the upper mould floor having apertures to receive and support respective ties.

The mould portions perferably comprise cast metal frames but, aternatively, may be fabricated in sheet metal. Preferably the mould portions are cast in aluminium to render them portable even when a block is curing in the mould.

In a preferred embodimentthe upper mould floor comprises a pair of removable rectangular deck plates. Alternatively, the mould floor may be formed intergrally with the mould portions or by a single, disposable hardboard or plastics sheet. The lower mould floor may be formed integrally with the mould portions or as one removable plate; in the preferred embodiment, however, the lower mould floor comprises two triangular deck plates. Preferably, the deck plates are made from sheet steel to combine strength with minimum thickness.

The lower mould floor is preferably provided with surface relief on its concrete-receiving face, to form an external face of a block wall which has a specific surface finish. The lowerfloor may, however, be covered by stone chippings or the like prior to casting.

One embodiment of the invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of one mould portion of a shutter block mould according to the present invention; Figure 2 is a plan view of the mould of Figure 1; Figure 3 is a vertical section taken along the line 3-3 of Figure 2, and Figure 4 is a perspective view of a shutter block cast in the mould of Figures 1 to 3.

Referring now to Figures 1 to 3 of the drawings, there is shown a concrete shutter block mould, generally indicated 1, comprising two rigid mould portions 2, 3 which are cast in aluminium in the form of respective frames, each having a triangular plan shape. The mould portions 2,3 are releasably interconnected in a vertical plane X-X (see Figure 2) corresponding to a diagonal of the assembled mould 1, to render the mould 1 self-supporting. The mould portions 2, 3 have three upright supports 4, one at each corner, which are interconnected by upper and lower transverse members 5,6 respectively.

The co-operating edges along which the mould portions 2, 3 are releasably connected comprise respective abutment faces 4A, formed parallel to the diagonal connection plane X-X on the upright supports 4 which, in the assembled mould 1, lie in the plane X-X, as shown in Figure 2. The mould portions 2, 3 are maintained in engagement by releasable clamping means which facilitate breaking of the mould 1 after curing of a cast block. In the example shown, the releasable clamping means comprise a pair of lugs 7 which are formed on each abutment face 4A of one mould portion 2 and engage in co-operating sockets 8 formed in the abutment faces of the other mould portion 3. The lugs 7 are each provided with a hole 7A for a locking pin 9 or wedge, one of which is shown in Figure 1.

The upper transverse members 5 of each mould portion 2, 3 are provided, on their inner surfaces, with respective ledges 10 which are of limited longitudinal extent and support an upper mould floor comprising a pair of removable deck plates 11, 12 (see Figures 2 and 3). The deck plates 11, 12 are made from sheet steel in a rectangular shape and abut each other at their inner edges which are notched to define two spaced-apart square apertures 13 which serve as supports for respective ties of a shutter block. The inner faces of the transverse members 5 are also provided above the ledges 10 with respective longitudinally extending tongues 14 on one mould portion 2, and corresponding grooves 15 on the other mould portion 3.

The lower transverse members 6 of each mould portion 2,3 rest on a supporting surface in use of the mould 1, and co-operate with a lower mould floor comprising a pair of removable deck plates 16,17.

The deck plates 16, 17 are made from sheet steel and are triangular in shape (see Figure 1), being inserted into respective recesses 18 in the base of each mould portion 2, 3 and having abutment edges co-planar with the plane X-X. Similarly to the upper transverse member 5, the inner faces of the lower transverse members 6 of each mould portion 2,3 are provided with tongues 19 and grooves 20 respectively.

In the mould shown, there are also provided intermediate transverse members 21, which interconnect neighbouring upright supports 4 in the same manner as the upper and lower members 5,6 and are located adjacent the uppertransverse mem bers 5, being similarly provided with respective ledges 22 for the deck plates 11, 12. In correspond ence with the other transverse members 5,6, the intermediate transverse members 20 of each mould portion 2, 3 are provided with tongues 23 and grooves 24 respectively.

The mould 1 is intended for use in casting a conveniently portable and self-supporting concrete shutter block, as shown in Figure 4.

The block, generally indicated 41, comprises two square, spaced apart walls 42,43, which are held rigidly together, and parallel to each other, by two precast, reinforced concrete ties 44. The opposing pairs of edges of the walls 42,43 are formed with complementary tongues 45 and grooves 46 which enable the walls of neighbouring blocks to be interlocked. A rigid interconnection between the walls is ensured by the ties 44 being provided with internal reinforcing rods 47 which project beyond the ends of the ties 44, and are embedded in the walls 42,43. As shown in broken outline, the ends of the ties 44 which are embedded in the walls 42, 43, are bent so as to lie parallel to the walls, and at right angles to the longitudinal axes of the ties 44, ensuring a firm anchorage of the ties in the walls 42, 43.

To produce a block as described above, the mould portions 2, 3 of the mould 1 are clamped together and placed on a horizontal planar surface over the lower deck plates 16,17, which are then located in their respective recesses 18 in the lower transverse members 6 to define the lower mould floor. The upper deck plates 11, 12, depending on the desired spacing between the walls of the block 41, are then placed on the ledges 10, 22 of either the upper or intermediate transverse members 5, 21 to define the upper mould floor. The ties 44 are located in the respective apertures 13 in the upper mould floor and concrete is poured onto the upper and lower mould floors to form the walls 42,43, of the block, the concrete enclosing the ends of the ties.The tongues 45 and grooves 46 of the block walls 42,43 are formed by the grooves 15,20,24, and tongues 14, 19,23 of the mould portion 3,2 respectively.

In an alternative method, the concrete may be poured onto the lower mould floor before the upper mould floor and the ties are emplaced.

The lower deck plates 16 may be provided with surface relief 16A, such as embossing, to provide the external, visible face of one wall 42 with a specific surface finish 42A. Alternatively, the lower mould floor may be covered with stone chippings or the like prior to pouring the concrete. It is more practical, however, to add the chippings to the exposed surface of the concrete which has been poured onto the upper mould floor and, after the concrete has been allowed to cure for 4 to 5 hours, to wash the surface with water from a high pressure hose to enhance the surface relief by eroding some of the concrete from between the chippings. This method allows better control over the surface finish, and generally requires less preparation and cleaning, than the previously described alternative method of adding the chippings to the lower mould floor.

Any desirable mix of concrete may be used forthe shutter blocks 41, but a preferred mix consists of 3 parts of 1Omm chippings, 11/2 parts of clean washed sand and 1 part of portland cement.

Concrete shutter blocks cast from the present mould can be superimposed or placed side by side with the edges of walls interlocked and accurately co-planar, thereby defining parallel-sided shuttering which forms a mould ready for the reception of wet concrete. No external support is necessary, since the ties 44 rigidly interconnect the block walls. The shuttering can be erected rapidly by unskilled labour, particularly since the interlocking tongues 45 and grooves 46 obviate the need for mortar joints or braces.

A shutter block cast in the present mould can be used to form a corner unit or an end unit with the use of suitable additional precast wall elements.

To cast an end unit, that is, a block in which the walls 42,43 are interconnected at one edge by a third wall element, one of the upper deck plates 11,12 and one of the lower deck plates 16, 17 are each replaced by respective deck plates which are narrower by the width of the third wall element. This element is placed vertically in the mould, at one side so as to be at right angles to the mould floors, prior to pouring the concrete in the usual way. When the concrete has cured, the block so formed has three walls and is suitable for building a blind end of a formwork wall.

In order to ensure a firm interconnection between the walls of the block, the third wall element is provided with a pair of reinforcing rods which project at each end from the sides of the element and are bent at right angles to the element so as to lie parallel to each mould floor. When the concrete for the block walls 42,43 is poured into the mould, the walls 42, 43 enclose these reinforcing rods.

Claims (24)

1. Amould for casting individually concrete shutter blocks of the type comprising two four-sided walls of concrete rigidly interconnected in a parallel spaced-apart relationship by at least two rigid ties the ends of which are embedded in the walls, each of the walls having two adjoining longitudinally tongued edges and two correspondingly grooved edges which permit neighbouring blocks to be interlocked when erected, in which the mould comprises two rigid portions which are releasably interconnected along co-operating edges in a vertical plane corresponding to a diagonal of the mould to render the mould self-supporting, the mould having an upper mould floor, which is horizontal in use of the mould, and adjacent internal tongues and grooves for moulding one wall of the shutter block, and a lower mould floor with adjacent internal tongues and grooves for moulding the other wall of the shutter block, the upper mould floor having apertures to receive and support respective ties.

2. A mould as claimed in Claim 1, in which the upper mould floor is removable, being inserted after assembly of the mould to rest upon internal ledges on the mould portions.

3. A mould as claimed in Claim 1 and Claim 2, in which the upper mould floor comprises at least two deck plates which, when inserted into the assembled mould, abut each other along cut-away edges to define at least two apertures for the ties.

4. A mould as claimed in Claim 3, in which the deck plates are rectangular.

5. A mould as claimed in Claim 1, in which the lower mould floor is removable, the floor being placed on a horizontal surface and surrounded by the assembled mould.

6. A mould as claimed in Claim 5, in which the lower mould floor comprises two triangular deck plates with respective abutment edges parallel to diagonal plane of connection of the mould portions.

7. A mould as claimed in Claim 3 and Claim 6, in which the deck plates are made from sheet steel.

8. A mould as claimed in any one of the preceding claims, in which the mould portions comprise cast metal frames having three upright supports interconnected by transverse upper and lower frame members formed with the respective tongues or grooves for casting the block walls.

9. A mould as claimed in Claim 2 and Claim 8, in which the upper transverse members are formed with respective said ledges for supporting the upper mould floor.

10. A mould as claimed in Claim 8 and Claim 9, in which the upright supports are further interconnected by intermediate transverse frame members having respective ledges for supporting an upper mould floor when the ledges on the upper members are not in use, and respective tongues or grooves for casting the block walls.

11. A mould as claimed in Claim 1 and Claim 8, in which the co-operating edges of the mould portions comprise respective abutment faces formed on the upright supports which, in the assembled mould, lie in the diagonal plane of connection.

12. A mould as claimed in any one of the preceding claims, in which the mould portions are cast in aluminium.

13. A mould as claimed in any one of the preceding claims, in which the mould is substantially cubic and the mould portions are triangular in plan shape.

14. A mould as claimed in any one of the preceding claims, in which the mould portions are provided with releasable clamping means.

15. A mould as claimed in Claim 14, in which the releasable clamping means comprise interengageable male and female elements on the cooperating edges of the mould portions.

16. A mould as in any one of the preceding claims, in which the mould portions are hinged together adjacent one pair of co-operating edges.

17. A mould as claimed in any one of the preceding claims, in which the lower mould floor is provided with surface relief on its concrete-receiving surface, to form an external face of a block wall which has a specific surface finish.

18. A method of casting concrete shutter blocks using the mould defined in Claims 1 to 17 comprising the steps of moulding a first block wall on the lower mould floor while releasably holding rigid ties in position vertically with their lower ends embedded in the concrete of the first block wall, the upper ends of the ties projecting through, and being held in place by, apertures in the upper mould floor onto which concrete is poured to form second block walls.

19. A method as claimed in Claim 18, in which the rigid ties are prefabricated from reinforced concrete.

20. A method as claimed in Claim 19, in which each tie is internally reinforced by a rod having end portions projecting beyond the ends of the ties and which are embedded into the block walls, the end portions being bent priorto casting so as to extend parallel to the faces of the walls.

21. A method as claimed in Claim 18, in which the ties are arranged so as to be mutually parallel and perpendicular to the block walls.

22. A concrete shutter block cast in a mould as defined in Claims 1 to 17 by the method defined in Claims 18 to 21.

23. A mould for casting concrete shutter blocks as herein described with reference to, and as shown in Figure 1,2 and 3 of the accompanying drawings.

24. A concrete shutter block as herein described with reference to, and as shown in Figure 4 of the accompanying drawings.