GB1572855A - Method of manufacturing laminated wood or laminated profiles - Google Patents

Description

(54) A METHOD OF MANUFACTURING LAMINATED WOOD OR LAMINATED PROFILES (71) We, AKTIEBOLAGET STATENS SKOGSINDUSTRIER, a Swedish Company, of Sveavägen 59, S- 10522 105 22 Stockholm, Sweden, 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 described in and by the following statement:- The present invention relates to a method of manufacturing wood laminates.

Wood laminates are normally manufactured by gluing together two or more layers of elongate pieces of sawn and smoothed wood. Wood laminates of the desired shape can be obtained by varying the dimensions of the layers from which the laminate is composed. The wood, in this case however, is of uniformly high quality, i.e. wood which is free of knots and other faults.

In accordance with the present invention it has now been found possible to use, in the manufacture of wood laminates, wood of an extremely poor quality, i.e. wood which contains knots and other faults, when the laminates are manufactured by a particular method.

The invention consists in a method of manufacturing an elongate laminated wooden structure, wherein there is placed on a primary lamella at least one intermediate lamella and a facing lamella (as hereinafter defined) said at least one intermediate lamella and said facing lamella comprising a plurality of substantially knotfree wood pieces each cut from a piece whose quality is poorer than that of said primary lamella, and mutually adjacent ones of said lamellae being joined to each other by longitudinally extending joints formed by grooves in a surface of a lamella mating with walls of longitudinally extending grooves in an adjacent surface of an adjacent lamella.

By facing lamella is meant a lamella having an outwardly facing smooth surface.

Conveniently, the primary and facing lamellae have arranged on one major surface thereof mutually parallel V-shaped grooves for interlocking engagement with the walls of similar grooves on the intermediate lamella or lamellae, the intermediate lamellae having grooves on two opposing surfaces thereof. The wood used for the lamellae other than the primary lamella is cut from poor quality wood having knots and other faults, said knots first being removed before forming the laminate. The acceptable pieces of wood thus obtained are too short for use in the previously known technique of fabricating laminates.By placing these further lamellae end-to-end in layers one above the other it has been found that the random positioning of the end-to-end joints of one lamella can be overlapped by the pieces of wood forming a lamella immediately above or below, thereby ensuring a high degree of mechanical strength even when the pieces of wood in the upper lamellae are joined end-to-end.

The invention will now be described in more detail with reference to the accompanying drawing, in which the invention is illustrated in conjunction with the manufacture of wood laminates for window casements, in which drawing: Figure 1 shows the different lamellae of the wood laminate prior to said lamellae being joined together, Figure 2 shows the wood laminate subsequent to said lamellae having been joined together, pressed and sawn lengthwise into two sections, and Figure 3 shows two completed wooden casement members.

For the manufacture of wooden window casement members, seasoned wood having the dimensions 125x25 mm and being of the highest quality is prepared for jointing by being grooved longitudinally along one surface thereof and is moved to an assembly station to serve as the primary lamella of the laminated wood (the lamella 1 in Figure 1).

Seasoned wood having the dimensions 42x 19 mm and being of the sixth quality is divided up on two groove cutting machines, one machine being arranged to cut longitudinally extending grooves on two opposing major surfaces of a piece of wood and the other to cut longitudinally extending grooves on only one major surface of a piece of wood. Subsequent to cutting the grooves the wood is transported to a sorting and cutting machine in which knots and other faults in the wood are removed.The accepted pieces of wood are then coated with an adhesive and moved to the assembly station, where pieces having grooves extending longitudinally on two opposed major surfaces thereof are placed on the primary lamella I to form two second separate lamellae 2 while a further lamella 3 comprising pieces of wood having grooves extending longitudinally on only one major surface thereof is placed on each lamella 2.

The thus formed laminate is then passed through a roller press, in which the lamellae are pressed together. Immediately after being pressed, the laminate is cut into two equal sections 4 (Figure 2) which are planed in a profile planing machine to produce two casement members 5 (Figure 3). These casement members are then moved to a cutting station in which they are cut into the desired lengths. These lengths are then stored until the glue has hardened, whereafter they are sent to the customer.

The casement members thus obtained have' an extremely high mechanical strength.

Prior to joining the lamellae together, sides of respective lamellae which are to lie against each other are longitudinally grooved. A layer of adhesive is then applied to the tops of the walls defining the grooves.

The wood pieces are then placed together and the laminate is charged to a roller press, in which, at the same time as the lamellae are being pressed together to bond the same, pressure is applied to the outermost ends of the lamellae seated upon the primary lamella so that the pieces of wood forming the respective lamellae are pressed firmly end-to-end. The lamellae are pressed under high pressure in the absence of heat, thereby enabling a high capacity. Since no heat is required, the method requires less energy than otherwise. When the lamellae are pressed together the grooves of mutually opposing surfaces of respective lamellae afford a mechanical strength such as to enable the laminate to be handled and stored whilst the glue hardens.

WHAT WE CLAIM IS: 1. A method of manufacturing an elongate laminated wooden structure, wherein there is placed on a primary lamella at least one intermediate lamella and a facing lamella (as hereinbefore defined) said at least one intermediate lamella and said facing lamella comprising a plurality of substantially knot-free wood pieces each cut from a piece whose quality is poorer than that of said primary lamella, and mutually adjacent ones of said lamellae being joined to each other by longitudinally extending joints formed by grooves in a surface of a lamella mating with walls of longitudinally extending grooves in an adjacent surface of an adjacent lamella.

2. A method according to claim 1, wherein said grooves have a V-shaped crosssection.

3. A method according to claim 2, comprising forming said laminated structure from a plurality of intermediate lamellae each comprising a plurality of pieces of wood whose quality is poorer than that of said primary lamella, each of said pieces having arranged on two opposed surfaces thereof a plurality of mutually parallel Vshaped grooves, wherein the walls defining the grooves of one adjacent lamella are placed in mating engagement with the grooves of the other adjacent lamella and the laminate pressed in a direction providing interlocking of the walls in said grooves and in a direction to provide endto-end abutment of the lamella sections.

4. A method as claimed in claim 3, wherein the crowns of the walls defining the grooves are coated with an adhesive prior to assembling the lamellae to form said laminate.

5. A method as claimed in claim 4, wherein the joints between adjacent lamella sections of one lamella are offset relative to the joints between adjacent lamella sections of an immediately adjacent lamella.

6. A method as claimed in any one of claims 1 to 5 substantially as hereinbefore described with reference to the drawings.

7. A wood laminate whenever prepared by the method as claimed in any of claims 1 to 6.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. divided up on two groove cutting machines, one machine being arranged to cut longitudinally extending grooves on two opposing major surfaces of a piece of wood and the other to cut longitudinally extending grooves on only one major surface of a piece of wood. Subsequent to cutting the grooves the wood is transported to a sorting and cutting machine in which knots and other faults in the wood are removed. The accepted pieces of wood are then coated with an adhesive and moved to the assembly station, where pieces having grooves extending longitudinally on two opposed major surfaces thereof are placed on the primary lamella I to form two second separate lamellae 2 while a further lamella 3 comprising pieces of wood having grooves extending longitudinally on only one major surface thereof is placed on each lamella 2. The thus formed laminate is then passed through a roller press, in which the lamellae are pressed together. Immediately after being pressed, the laminate is cut into two equal sections 4 (Figure 2) which are planed in a profile planing machine to produce two casement members 5 (Figure 3). These casement members are then moved to a cutting station in which they are cut into the desired lengths. These lengths are then stored until the glue has hardened, whereafter they are sent to the customer. The casement members thus obtained have' an extremely high mechanical strength. Prior to joining the lamellae together, sides of respective lamellae which are to lie against each other are longitudinally grooved. A layer of adhesive is then applied to the tops of the walls defining the grooves. The wood pieces are then placed together and the laminate is charged to a roller press, in which, at the same time as the lamellae are being pressed together to bond the same, pressure is applied to the outermost ends of the lamellae seated upon the primary lamella so that the pieces of wood forming the respective lamellae are pressed firmly end-to-end. The lamellae are pressed under high pressure in the absence of heat, thereby enabling a high capacity. Since no heat is required, the method requires less energy than otherwise. When the lamellae are pressed together the grooves of mutually opposing surfaces of respective lamellae afford a mechanical strength such as to enable the laminate to be handled and stored whilst the glue hardens. WHAT WE CLAIM IS:

1. A method of manufacturing an elongate laminated wooden structure, wherein there is placed on a primary lamella at least one intermediate lamella and a facing lamella (as hereinbefore defined) said at least one intermediate lamella and said facing lamella comprising a plurality of substantially knot-free wood pieces each cut from a piece whose quality is poorer than that of said primary lamella, and mutually adjacent ones of said lamellae being joined to each other by longitudinally extending joints formed by grooves in a surface of a lamella mating with walls of longitudinally extending grooves in an adjacent surface of an adjacent lamella.

2. A method according to claim 1, wherein said grooves have a V-shaped crosssection.

3. A method according to claim 2, comprising forming said laminated structure from a plurality of intermediate lamellae each comprising a plurality of pieces of wood whose quality is poorer than that of said primary lamella, each of said pieces having arranged on two opposed surfaces thereof a plurality of mutually parallel Vshaped grooves, wherein the walls defining the grooves of one adjacent lamella are placed in mating engagement with the grooves of the other adjacent lamella and the laminate pressed in a direction providing interlocking of the walls in said grooves and in a direction to provide endto-end abutment of the lamella sections.

4. A method as claimed in claim 3, wherein the crowns of the walls defining the grooves are coated with an adhesive prior to assembling the lamellae to form said laminate.

5. A method as claimed in claim 4, wherein the joints between adjacent lamella sections of one lamella are offset relative to the joints between adjacent lamella sections of an immediately adjacent lamella.

6. A method as claimed in any one of claims 1 to 5 substantially as hereinbefore described with reference to the drawings.

7. A wood laminate whenever prepared by the method as claimed in any of claims 1 to 6.