GB1586512A - Building sheets - Google Patents

Description

(54) IMPROVEMENTS IN AND RELATING TO BUILDING SHEETS (71) We, D+ANSK ETERNIT- FABRIK A/S, a Company organised under the laws of Denmark, of Postbeks 763, 9100 Aalborg, Denmark, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly des cribed in and by the following statement: This invention relates to a method of manufacturing building sheets and building sheets manufactured according to this method. More specifically the invention is concerned with an improvement in the manufacturing of building sheets consisting of an inorganic, preferably hydraulic, binding agent with fibre reinforcement, of which at least part of the fibres are flexible, organic fibres.

Building sheets of the kind in question are usually made from asbestos fibre-reinforced cement compositions which may include other types of reinforcing fibres and other active or inactive fillers to achieve a preferred composition for a specific use of the building sheet, for example to achieve an advantageous surface for protection of the sheet or to achieve a decorative effect.

Building sheets of this type are used for a number of purposes, for example as roofing sheets and as cladding sheets for interior and exterior use.

The mounting of such sheets often requires that they are cut to size and further that a number of sizes and shapes are available to fit the building or the construction in a suitable and practical manner.

It is well known that reinforced building sheets can be manufactured in a number of shapes such as corrugated sheets, curved sheets, bent sheets, and ridge sheets in the form of ridge tiles.

However, it is difficult and often unpractical and uneconomical to manufacture and keep in stock a great number of different shapes of these articles. Usually such parts which are awkward in shape are hand-made.

According to one aspect, the present invention provides a method of manufacturing a building sheet consisting of an inorganic preferably hydraulic binding agent with fibre reinforcement of which at least part of the fibres are flexible organic fibres, the method including stamping the building sheet in its moist and still plastic phase with one or more grooves so that, when hardened, the sheet may be bent along the groove or grooves to constitute two or more parts which are con nected by one or more hinges.

Building sheets containing an inorganic, hydraulic binding agent are brittle and crack completely when bent beyond a certain, usually very small, angular limit. When the sheets are manufactured according to the invention the bending of the sheet is performed so that the sheet cracks along the stamped groove. The basic material i.e. the matrix cracks more or less completely but the sheet parts hold together because of the flexible, organic fibres which hinge the parts together, possibly with some at least of the matrix in the crack or cracks adhering to the fibres and sheet parts.

Preferably, the sheets are stamped from one or both sides in a manner which results in a concentration of the organic fibres at the location of the or each stamped groove. Thus, the stamping may be carried out in such manner that it functions to compress the sheet to push aside part of the matrix from the groove and retain the fibres in the groove.

A surplus of organic, flexible fibres may during the forming of the sheets be added at the location where the groove or grooves are to be stamped. The stamping may be a die stamping operation.

The invention also comprises a building sheet manufactured according to the first aspect, which sheet has a fibre reinforcement fully or partly composed of synthetic, organic fibres. Usually the reinforcement of the build ing sheets of this kind is composed of a mixture of fibres, at least part of which has to be flexible fibres in order to ensure that parts of the bent sheet are hinged, as the inorganic fibres, such as mineral wool fibres and asbestos fibres, are as brittle as the matrix and loose their cohesion when bent.

Preferably, the basic material of the sheet is fibre reinforced cement having an additional reinforcement consisting of synthetic, organic fibres which, as a consequence of the stamping, concentrate along the bottom of the stamped groove or grooves.

The basic material consisting of a fibre reinforced cement is a well known building material usually with inorganic fibres which may break when the stamping is carried out, whereas the organic flexible fibres, on the other hand, are elastic fibres which retain their flexibility within the mass and are pressed to the bottom of the groove or grooves, thus functioning as a concentrated reinforce ment at the location where the crack or cracks are made by way of bending the sheet.

In a modified embodiment of the building sheet according to the invention, the basic material of the sheet is mineral flake reinforced cement having an additional reinforcement consisting d synthetic, organic fibres being, as a consequence of the stamping, concentrated along the bottom of the groove or grooves.

The flake reinforcement of the sheet is comparable with the inorganic fibre reinforce ment in the sheet proper, but in order to maintain sufficient sheet strength in the groove or grooves the concentration of the flexible fibres at this location is imperative in order also to include the situations where the sheet is used as a plane sheet.

To ensure that the invention may be better understood examples of the constructional features of the sheets according to the in vention will now be described with reference to the accompanying drawings in which: - Figure 1 shows a cross-section of a sheet with a groove on one side of the sheet; Figure 2 shows a cross-section of a sheet with two opposite grooves; of Figure 1 or Figure 3 shows the sheet 2 seen from above; Figures 4 and 5 are side views of sheets bent to different angles between two sections of the sheets; Figure 6 illustrates a plane sheet seen from above with a number of grooves to form a part of complex shape; and Figure 7 illustrates perspectively the sheet of Figure 6 when bent.

Figures 1 to 4 of the drawings show a building sheet comprising two sections 1 and 2. The building sheet shown in Figure 1 has a groove 3 and the sheet shown in Figure 2 has two opposite grooves along which the building sheet may be bent, as illustrated by the examples in Figures 4 and 5, to form different angles between the two sections 1 and 2 of the sheets to be used as ridge tiles.

The matrix is an inorganic, hydraulic bind ing mass based on cement and asbestos fibres and being reinforced with polypropylene fibres.

When bent, the basic material breaks, whereas the polypropylene fibres indicated at 5 form a hinge connecting the sections 1 and 2 of the sheet. Cracks may form in the groove so that the resulting ridge tile is not completely watertight but this may be an advantage for this specific use of the sheets, as the cracks may serve as vent slits.

The reinforcement of the matrix may be obtained by other types of fibres, mixtures of fibres or fibres and other reinforcing elements such as flakes of mineral material such as of mica, and the matrix may include fillers, coloured particles and pigments, for example.

Further, the grooves may be discontinuous and may vary in depth along their length and different grooves may be of different depths.

The sheets described can be utilized as plane sheets or as bent sheets to manufacture a number of shaped parts in an advantageous manner, for example ridge tiles, corners and shafts.

Figures 6 and 7 thus illustrate an example of a sheet 6 having a number of grooves 7, 8, 9 and 10 to constitute when bent as indicated in Figure 7 a complex ridge tile for an intersection of a mansard roof.

WHAT WE CLAIM IS : - 1. A method of manufacturing a building sheet consisting of an inorganic binding agent with fibre reinforcement of which at least part of the fibres are flexible organic fibres, the method including stamping the building sheet in its moist and still plastic phase with one or more grooves so that, when hardened, the sheet may be bent along the groove or grooves to constitute two or more parts which are connected by one or more hinges.

2. A method as claimed in Claim 1 in which the binding agent is a hydraulic binding agent.

3. A method as claimed in Claim 1 or Claim 2 in which the stamping is a die stamping operation.

4. A method as claimed in Claim 1 or Claim 2 or Claim 3 in which the stamping is performed in a manner which results in a concentration of the organic fibres at the location of the or each stamped groove.

5. A method as claimed in any of the preceding claims in which registering grooves are stamped from the opposite sides of the sheet.

6. A method as claimed in any d the preceding claims in which additional flexible organic fibres are added to the sheet in the region to be stamped.

7. A building sheet manufactured by a method as claimed in any of the preceding

Claims (1)

1. claims.

   8. A building sheet as claimed in Claim 7 in which the sheet is made of fibre reinforced cement having an additional reinforcement consisting of synthetic, organic fibres which, as a consequence of the stamping, are concentrated along the bottom of the stampjed groove or grooves.

   9. A building sheet as claimed in Claim 7 in which the sheet is made of mineral flake reinforced cement having an additional reinforcement consisting of synthetic, organic fibres which, as a consequence of the stamping, are concentrated along the bottom of the groove or grooves.

   10. A method of manufacturing a building sheet substantially as described herein with reference to the accompanying drawings.

   11. A building sheet substantially as described herein with reference to Figures 1, 3, 4 and 5 or to Figures 2, 3, 4 and 5 or to Figures 6 and 7 of the accompanying drawings.