CONSTRUCTION BOARD

Abstract: The invention relates to a longitudinal laminate board (1) of binder fixed mineral wool, which is suitable as a core of a sandwich element having surface layers of e.g. thin sheet metal. The laminate board consists of adjacently disposed longitudinally directed rods (2), whose fibre planes form a right angle to the plane of the laminate board. The length of the rods is less than half of that of the laminate board and they are jointed to each other. The joints are distributed over the laminate board so as to eliminate their weakening effect on the resistance of the board. None of the joints is immediately next to any of the ends of the laminate board, when the board is being used as a one-field board with supports at the ends, or immediately next to a support line, when the board is being used as a multi-field board. None of the joints is preferably within the area (a) next to the ends or support lines between the ends, whereby a = L : 1,90n, L = the length of the laminate board or the span between support lines and n = the number of laminates laterally in the laminate board. At a greater distance from the ends or the support lines, the required distance between the joints is less.

Description: Construction board The invention relates to a longitudinal laminate board of binder fixed mineral wool, which is suitable as a core of a sandwich element, having surface layers, e.g. of sheet metal, on each side, consisting of adjacently disposed rods whose longitudinal direction forms a right angle to the plane of the laminate board. Laminate boards of this type are prior known, having been used for instance in shipbuiding industry as insulating walls of various spaces. Sandwich elements of mineral wool have been utilized to some extent in building industry. However, so far long elements have not been available, neither as roof or floor elements, nor as wall elements. o The idea of rotating cut laminates 90 and of reassembling them in the turned position, thus providing a laminate board having fibres orientated perpenpendicularly to the plane of the board, is prior known. Such a laminate board has excel¬ lent resistance properties and is able to transmit shearing forces between its surface planes. Finished sandwich elements of mineral wool with the fibres orientated perpendicularly to the surface plane of the ele¬ ment would be usable as roof, floor and wall elements, thus simplifying construction operations noticeably. The object of the present invention is to provide long lami¬ nate boards which are usable as a core of supporting sandwich elements for roof, floor and wall constructions. According to the invention, this object has been achieved by composing the laminate board of rods, the length of which is less than half of the length of the laminate board and by bringing these aligned rods into contact without intervals, thus forming joints, and none of the joints is in the imme¬ diate vicinity of any of the ends of the laminate board, when the board is being used as a one-field board having supports at the ends, or immediately next to a support line, when the board is being used as a multi-field board. According to the invention, a long construction board, of up to 9-10 m, can be provided by means of laminates rotated and assembled in the same manner, without handling mineral wool mats and cut laminates of a corresponding length. By compo¬ sing the laminate board of rods of a length that is less than half of the length of the laminate board so that aligned rods are in contact without intervals, forming joints between each other, and by appropriately distributing the joints over the surface of the laminate board, a board is achieved which, when used as a core of a sandwich element, has resistance properties corresponding to a board without joints, i.e. in which the weakening effect of the joints has been eliminated. According to a preferred embodiment of the laminate board, none of the joints is disposed closer to a support of the la¬ minate board than a when a = L : l,90n, L = the length of the laminate board, when the board is being used as a one-field board, and L = the span, when the board is being used as a multi-field-board, and n = the number of laminates laterally in the laminate board. The parametre a indicates the length of the critical area within which the existence of joints has to be limited in order prevent the joints from weakening the resistance of the board when used in building constructions. Critical areas exist next to the ends of the board, where the boards are supported, and next to the support lines between the ends. A force concentration namely arises at intermediate supports like at the ends, when the support points are provided there. The conclusion concerns elements in a horizontal position as well as elements in a vertical position. As a general rule the distance a, indicating the length of the critical area, equals L : 2n . Since the support lines, among others, have a certain extension, the length a should be somewhat longer, and thus the length L is appropriately divided by l,90n. According to another preferred embodiment, maximally one joint is disposed within the distance 2a from any of the ends or support lines of the laminate board. According to a further development of the invention, maximally two joints are within the distance 3a from any of the ends or support lines of the laminate board. Further, maximally three joints should preferably be included within any interval a along the length of the laminate board. Further, the distance between the joints of two adjacent rows of joints should preferably equal at least the thickness of the rods . These parametreβ a, L and n are significant when producing the laminate boards according to the invention. As described more in detail in our parallel application 885847, filed on the same date, the laminate boards are manufactured by cut- ting from mineral wool mats that are shorter than the lamina¬ te board rods in the longitudinal direction of the wool mat, o by turning the rods 90 and assembling them with end faces against each other into "long rods", which consequently will comprise equally spaced joints. From these long rods, lamina¬ tes of the desired length are cut and assembled into a la¬ minate board. The position of the joints in the laminate board is determined by the legnth of the rods having been cut and assembled into a long rod with regard to the length of the laminate board and by the manner in which the long rods are assembled into a laminate board. According to the present invention, it is essential that the joints be distributed over the laminate board and especially with regard to the zone next to the ends and the support points so as to eliminate the weakening influence of the joints. This relation is obtained by fulfilling the condi¬ tions defined for the parametres a, L and n in the claims. The parametres a, L and n are used for determining the exact position for cutting off a long rod into a laminate of the laminate board and for phase displacing the long rod with re¬ gard to the preceding long rod in the board. The parametres are used for programming a computer for automatic control of the cutting of the long rods. A preferred embodiment of the laminate board according to the invention is described below with reference to the enclosed figure. The enclosed figure 1 shows a preferred embodiment of the la¬ minate board according to the invention. The laminate board is indicated by 1, the rods by 2, and the joint between the rods forming the laminates of the laminate board by 3. In the rods 2 forming the outmost laminate, the vertical orientation of the fibre plane has been indicated. . It can be noted that the joints 3 are relatively equally distributed over the laminate board and a comparison with the parametres above shows that all the criteria are being ful¬ filled. As described in our parallel application mentioned above, the manufacture of the laminate board is carried out by assemb¬ ling laterally rods that have been cut from a mineral wool and rotated in order to form the laminate board. The asemb- ling of the rods that have been cut and rotated can be ac¬ complished in various manners. In a preferred manner, the rods are assembled consecutively into a long rod, in which rods having the desired length (=the length of the laminate board) are cut and assembled in¬ to a laminate board. In another preferred manner, several rods are cut from the mineral wool sheet and rotated and subsequently phase displa¬ ced axially. The phase displaced rods are subsequently as¬ sembled with end faces against each other with the preceding flow of correspondingly cut and phase displaced rods into a flow of long rods, in which a length equalling that of the laminate board is cut off. After that, the two surface layers are applied onto the laminate board. Provided with surface layers, which may be of thin sheet me¬ tal, a concrete layer, minerite or similar, the construction board according to the invention is usable as a supporting wall or roof element. Owing to its construction, the board has good fire and heat insulating properties and is simple.

Claims: Claims 1. A longitudinal laminate board of binder fixed mineral wool which is suitable as a core of a sandwich element having surface layers, e.g. of sheet metal, on each side, consis¬ ting of adjacently disposed rods whose longitudinal direction coincides with that of the laminate board and in which the fibre plane forms a right angle to the plane of the laminate board, characterized in that the laminate board is composed of rods the length of which is less than half of the length of the laminate board, and in that the aligned rods are in con¬ tact without intervals, thus forming joints, whereby none of the joints is disposed immediately next to any of the ends of the laminate board, when the board is being used as a one- field-board with supports at the ends, or immediately next to a support line, when the board is being used as a multi-field- board. 2. A laminate board according to claim 1, characterized in that none of the joints is disposed closer to a support line of the laminate board than a, when a = L : l,90n, L = the length of the laminate board, when the board is being used as a one-field board, and L = the span, when the board is being used as a multi-field board, and n = the number of laminates laterally in the laminate board. 3. A laminate board according to claim 2, characterized in that maximally one joint is disposed within the distance 2a from any of the ends or a support line of the laminate board. 4. A laminate board according to claim 2 or 3, characterized in that maximally two joints are within the distance 3a from any of the ends or a support line of the laminate board. 5. A laminate board according to any of. claims 2-4, characterized in that maximally three joints are within the interval a somewhere along the length of the laminate board.

Inventors: BRUNILA ESKO, HESELIUS LARS, BRUNILA, ESKO, HESELIUS, LARS
Applicants: PARTEK AB, OY PARTEK AB
Application year: 1989
Main classification: E04B1
IPC codes: E04B1, E04C2