CONSTRUCTION BOARD AND ITS MANUFACTURING METHOD

Abstract: The invention relates to a longitudinal laminate board (1) of mineral wool to be used as a core of a sandwich element having surface layers preferably of thin sheet metal on each side. The laminate board consists of adjacently disposed rods (2) whose fibre plane forms an essentially right angle to the plane of the laminate board. The rods are jointed within the laminate board, but the joints (3) are prepared so as to eliminate their weakening influence on the board. This has been achieved by matching the shape of the jointed end surfaces and connecting them. The end surfaces may be glued, compressed, form a finger joint, etc. in order to increase the strength of the joint. The invention also relates to a method for manufacturing the sandwich element. Having been cut from a mineral wool board, the rods are rotated (IIIa) 90 DEG and assembled (Va) with end surfaces facing each other into rods, are cut to a length equalling the one of the laminate board and are assembled into a laminate board onto which the surface layers are applied during lateral compression.

Description: Construction board and its manuf cturing method The invention relates to a construction board, in particular to longitudinal laminate board of mineral wool, which is appropriat as a core of a sandwich element having a surface layer e.g. of sheet metal on each side. The laminate board conβietβ of adjacen ly disposed rods, whose fibre plane forms essentially a right angle to that of the laminate board and at least a number of the rods being shorter than the laminate board. The invention also relates to a method for manufacturing the la¬ minate board, in which rods are cut out from a mineral wool shee with a length different from the one of the laminate board, are o rotated 90 about their longitudinal axes and are assembled int a laminate board. Laminate boards of this type are prior known and have been imple mented for instance in naval industry as insulating walls of various spaces. Sandwich elements of mineral wool have been utilized to some ex¬ tent in naval industry. So far long supporting elements have not however, been available, neither as ceiling, floor nor wall elements . Finished sandwich elements of mineral wool with the fibres orien ted perpendicularly to the surface plane of the element would, owing to its resistance properties, be usable as supporting roof floor and wall elements and would thus simplify building operations greatly. The object of the present invention is thus to provide longitu¬ dinal laminate boards usable as a core of supporting sandwich elements for roof, floor and wall constructions as well as a method for manu acturing such laminate boards. According to the invention, this object has been achieved by matching the opposite end surfaces of two aligned rods and connecting them and further by providing a method in which the rods are assembled with end surfaces facing into longitudinal rode, from which rods equalling the length of the laminate boards are cut off and connected laterally to form the laminate board. Thus, the laminate board of the invention is longitudinal, it is made of binder fixed mineral wool and is appropriate for use as a core of a sandwich element, whereby it is combined with surface layers, of sheet metal for instance, on each side. The laminate core is formed of adjacent rods whose fibre plane is perpendicu¬ larly oriented to the plane of the laminate board and at least a number of the rods being shorter than the laminate board. According to the invention, the opposite end surfaces of two aligned rods are matched and interconnected. At least some of the rods being shorter than the laminate board, such rods consist of jointed rods. In this case it is essential that the end surface be connected so that the resistance of the laminate board is not deteriorated. According to a preferred embodiment of the laminate board, the en- surfaces are glued against each other. According to another em¬ bodiment, the end surfaces' are pressed against each other forming border layer in which fibres from both surfaces are in contact with each other, engaging into each other. According to a preferred embodiment, the matching end surfaces can be inclined so as not to form a right angle to the longitudi¬ nal axis of the rods. According to a further developed embodiment the end surfaces form a right angle to the plane of the laminate board, being simultaneously and preferably tilted towards the longitudinal axis of the rods. According to a further embodiment of the laminate board, the end surfaces form a so-called finger joint, the fingers forming pro¬ jections and grooves parallel to the plane of the laminate board. A laminate board according to the invention is produced in a known manner by cutting rods in a mineral wool board having a length different from the one of the laminate board, are rotated o 90 about their longitudinal axes and are assembled to form a la¬ minate board. According to the invention, the rods are connected with end sufa- ces facing each other into longitudinal rods, in which rods ha¬ ving the length of the laminate board are cut off and intercon¬ nected laterally to form the laminate board. The connecting of the rods that are cut from the mineral wool board and rotated can take place in various manners. One preferred manner is to assembl cut off and rotated rods successively into a rod, from which rods of the desired length are cut and connected into a laminate board The joints of the rods will then have a random distribution over the laminate board. Another preferred embodiment is cutting several rods in the mine¬ ral wool board and turning them and subsequently phase displa¬ cing them axially. The phase displacement is essential conside¬ ring that the joints must not be transversely aligned in the fi¬ nished laminate board. By means of the phase displacement, a dif¬ fusion of the joints is provided. The phase displaced rods are then connected with end surfaces facing each other with the pre¬ ceding flow of correspondingly cut and phase displaced rods for¬ ming a flow of longitudinal rods, in which a length equal to the one of the laminate board is cut in order to form the laminate board. According to a preferred embodiment of the process, the rods are connected with a glue joint by applying glue to the end surfaces before connecting and fixing e.g. by drying subsequent to the forming of the laminate board. The glue application is appropria¬ tely performed before the phase displacement of the rod flow. According to another preferred embodiment of the process, the end surfaces of the rods are face milled or prepared so as to match the surfaces well, before a possible glue application. According to another preferred embodiment, the future lateral surfaces of the rods are face milled or prepared so that the rods will fit tightly to each other. According to another embodiment, traces are made in the end faces of the rods, parallel to the plane of the laminate board or perpendicular to these, so as to provide a finger joint between the rods . According to a further embodiment, the rods are pressed together during the connecting moment at a pressure exceeding 100 Pa, pre¬ ferably 500 Pa. The mineral wool mat used as starting material consists of a bin¬ der fixed mineral wool, which may be a rock wool or a glass wool, terming essentially plane parallel layers consisting of vitreous fibres more or less in disorder. By rotating the rods cut from the mat, rods having vertically- oriented fibres are obtained, which is valuable for the resistance requirements of the laminate board when used as a construction element. This fibre orientation, al¬ lowing shearing forces to be transferred between the surface pla¬ nes of the board, enables the use of very long boards, of the siz order of 9-10 m, for constuction purposes. The manufacture of ribs or a laminate mat of that length by means of conventional methods is difficult and would require complicated transport mechanisms. With the process according to our invention, again, no complicated equipment is needed and the space requirement can also be considered moderate. By starting from shorter mineral wool webs when manufacturing the said long elements, i.e. laminate boards, and by cutting rods in these which together with other shorter rods are assembled into "longitudinal rods" and by cutting rods of the desired length in these long rods, i.e. of the length of the laminate board, a pro¬ cess has been achieved that is easy to accomplish and results in a laminate board of the desired length. Due to the fact that the long rods composed of shorter rods are interconnected in an appropriate manner, such as compressing with interlocking fibres, glueing, engaging end surfaces like finger joint locking, etc. the laminate board has the resistance provided by the mineral wool together with the sandwich surface elements. On the other hand, the weakening influence of the joints has been eliminated. The various manufacturing steps are simple and can be varied in different ways. A preferred embodiment of the laminate board of the invention and its manufacture will be described below with reference to the enclosed figures, in which figure 1 shows a perspective of a laminate board, figure 2a shows an individual rod in perspective and on a larger scale, figure 2b shows an individual rod with a joint, figure 2c shows an individual rod with a joint as an embodiment different from the preceding figure, figure 3 shows a rod with a finger joint, figure 4 shows a detail enlargement of a joint produced by com¬ pressing, figure 5 shows an embodiment of the manufacture of a laminate board as a flow chart, figure 6 shows another embodiment of the manufacture of a lamina¬ te board as a flow chart, figure 7a shows a manner of applying glue to milled end surfaces and figure 7b shows compressing of the surfaces of figure 7a. Corresponding parts are indicated with the same reference nume¬ rals in all the figures. Figure 1 shows a laminate board consisting of seven laminates 2, each consisting of two jointed rods. The joint is marked with 3. The figures 2a show a jointless rod in which the fibre plane and the fibre orientation are indicated by the thin lines. The joint 3a of figure 2b is an inclined joint in which the end surfaces do not form a right angle to the axis of the rod, but form a right angle to the lateral plane of the rod. The joint 3b in figure 2c is also an inclined joint, in which the end -surfaces do not either form a right angle to the axis of the joint, but again, form a right angle to the plane of the laminate board. Figure 3 shows -a rod with a finger joint and figure 4 shows an enlargement of a joint produced by compressing the end surfaces. In figures 3 and 4, the end surfaces are perpendicular to the axis of the rod. The joint 3d in figure 4 indicates how the fib¬ res in each end surface penetrate into the opposite end surface. Figure 5 shows an embodiment of the manufacture of a laminate board according to the invention. Step la indicates the feeding of mineral wool boards produced by oscillating output, one at a time. Owing to the oscillating output, the fibre orientation is essentially perpendicular to the longitudinal axis of the web. In the step Ila the board is cut o into rods rotated 90 about their axes, thus yielding an essen¬ tially vertical fibre orientation in the formed sandwich element. A possible mechanical treatment of the end surfaces and a possib¬ le glue application is carried out just before or after the rota¬ tion, in step Ilia. The grinding of the future lateral surfaces o the rods is appropriately done in this step. Step IVa relates to the feeding of a rod in its longiduinal direction towards prece¬ ding rods, disposed with ends facing each other and being aligned The first rod is in contact with an edge at the height of the point where the rods are assembled into a laminate board. Step Va indicates the connecting of the end surfaces of the rods, where a rod iβ pressed against the preceding rod and the end surfaces are fixed Via against each other. In step Vila the front end of the longitudinal rod iβ cut off to a length equalling the one of the laminate board, after which the cut off rod iβ pushed laterally towards the collecting spot Villa and from there further to the spot IXa where the laminate board is formed and compressed late¬ rally. Synchronically with the feeding of surface layer, the fi¬ nished laminate core is fed in the step X to the spot where the one surface layer and subsequently the second surface layer are t be applied. Finally the sandwich element is subject to a heat and pressure treatment for final drying and curing. Figure 6 shows another embodiment of the manufacture of a lami¬ nate board according to the invention. Steps IVb-VIb are in reali ty subsequently aligned with steps Ib-IIIb. Because of lacking space on the paper, the figure has been split longitudinally. Step lb indicates the "input of material sheets one at a time. The manufacture is continuous in the longitudinal direction of the material sheet. The material sheet is fed and cut longitudi¬ nally in step lib into the desired number of rods. The future lateral surfaces of the rods are here subject to mechanical prepa ration, normally grinding. The cut material board is fed and the o rod.s are rotated 90 about their longitudinal axis in step III. Here the possible mechanical preparation of the ends of the rods and/or the glue application approriately takes place. The rotated rods are pushed towards the preceding flow of rods in step IVb while the rods are being mutually phase diplaced in order to diffuse the joints longitudinally on the laminate board being prepared. When forwarding the rods a pressure is app¬ lied in the longitudinal direction of the board in order to press the ends of the rods against each other and to join them well. In step Vb the laminate board consisting of longitudinal rods is cut to the desired length. In step Vlb the laminate board having the final dimensions is fed to the spot where the surface layers are applied under lateral pressure, first the one and the the other. The surface layers are usually of thin sheet metal, but can also be construction boards like minerite boards, moul¬ ded beton layers. Finally the sandwich element obtained is sub¬ ject to drying and curing. The processes of manufacturing the laminate board described abo¬ ve are merely two preferred embodiments. Besides these, there are alternative processes for manuf cturing the board. Essential for them all is that the starting material is a mineral wool sheet of a length different from the one of the laminate board, normally an essentially shorter wool sheet, in which rods are cut, are rotated and connected longitudinally and assembled into a laminate board.

Claims: Claims 1. A longitudinal laminate board <1> of binder fixed mineral wool, appropriate as a core of a sandwich element having a surface layer, e.g. of sheet metal, on each side, consisting of adjacent¬ ly disposed rods (2) whose fibre orientation essentially form a right angle to the plane of the laminate board and at least a number of the rods being shorter than the laminate board, characterized in that the opposed end surfaces of two rods (2) that are shorter than the laminate board and are aligned, matched and interconnected. 2. A laminate board according to claim 1, characterized in that the end surfaces are glued to each other. 3. A laminate board according to claim i or 2, characterized in that the end surfaces are pressed to each other so as to form a border layer, comprising fibres from both rods <2) . 4. A laminate board according to any of the preceding claims, characterized in that the end surfaces form a non-right angle to the longitudinal axis of the rods (2). 5. A laminate board according to any of the preceding claims, characterized in that the end surfaces form a right angle to the plane of the laminate board (1). 6. A laminate board according to any of claims 1-3, characterized in that the end surfaces form a so-called finger joint . 7. A method for manufacturing a laminate board Cl) according to claims 1-6, in which rods are cut from a mineral wool board ha¬ ving a length different from the one of the laminate board, are o rotated 90 about their longitudinal axes and are assembled into a laminate board, characterized in that the rods (2) are first assembled CVa) with end surfaces facing each other into longitudi¬ nal rods C4) from which rods equalling the length of the lami¬ nate board are cut CVIIa) and assembled laterally in order to form the laminate board. 8. The method according to claim 7, characterized in that a o flow of 90 rotated rods C2) deriving from the laminate cutting of a mineral wool sheet are phase displaced CVb) axially, are connected with end surfaces facing each other with the preceding flow of correspondigly cut and phase displaced rods into a flow of longitudinal rods C4) , in that rom the phase diplaced flow of rods is subsequently cut CVb) a length equalling the one of the laminate board in order to form a laminate board Cl). 9. A method according to claim 7, characterized in that a flow of rods deriving from the laminate cutting of a mineral wool board are combined one by one into a longitudinal rod ) in which rods equalling the length of the laminate board Cl) are cut and assembled in order to form a laminate board. 10. A method according to claim 7, characterized in that the rods C2) are assembled by glue jointing by applying a glue on the end surfaces before these are assembled and before the as¬ sembly is fixed, e.g. by drying. 11. A method according to claim 8, characterized in that the glue application is carried out before the phase displacement of the rod flow. 12. A method according to any of claims 7-11, characterized in that the future lateral surfaces of the rods are face milled or prepared in some other manner. 13. A method according to any of claims 7-12, characterized in that the end surfaces of the rods C2> are face milled or prepared in some other manner so as to match the surfaces, for instance parallel, before assembling them and applying a possible glue.

Inventors: BRUNILA ESKO, HESELIUS LARS, PELTO BJARNE, WILLMAN TARMO, BRUNILA, ESKO, HESELIUS, LARS, PELTO, BJARNE, WILLMAN, TARMO
Applicants: PARTEK AB, OY PARTEK AB
Application year: 1989
Main classification: E04C2
IPC codes: E04C2