Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27M—WORKING OF WOOD NOT PROVIDED FOR IN SUBCLASSES B27B - B27L; MANUFACTURE OF SPECIFIC WOODEN ARTICLES
  • B27M1/00—Working of wood not provided for in subclasses B27B - B27L, e.g. by stretching
  • B27M1/003—Mechanical surface treatment
  • B27M1/006—Mechanical surface treatment for preparation of impregnation by deep incising
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27M—WORKING OF WOOD NOT PROVIDED FOR IN SUBCLASSES B27B - B27L; MANUFACTURE OF SPECIFIC WOODEN ARTICLES
  • B27M3/00—Manufacture or reconditioning of specific semi-finished or finished articles
  • B27M3/0013—Manufacture or reconditioning of specific semi-finished or finished articles of composite or compound articles
  • B27M3/0086—Manufacture or reconditioning of specific semi-finished or finished articles of composite or compound articles characterised by connecting using glue
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B21/00—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board
  • B32B21/13—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board all layers being exclusively wood
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
  • B32B3/02—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by features of form at particular places, e.g. in edge regions
  • B32B3/06—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by features of form at particular places, e.g. in edge regions for securing layers together; for attaching the product to another member, e.g. to a support, or to another product, e.g. groove/tongue, interlocking
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/03—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers with respect to the orientation of features
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2255/00—Coating on the layer surface
  • B32B2255/08—Coating on the layer surface on wood layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2255/00—Coating on the layer surface
  • B32B2255/26—Polymeric coating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/732—Dimensional properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2479/00—Furniture

Definitions

• the present disclosure relates to a method for producing a medium-dimension construction element, MDCE, of wood, wherein the MDCE has an arbitrary length and has a cross section with a width in the range 3-25 cm and a height in the range 0.5-4 cm.
• the present disclosure further relates to an MDCE and a furniture component, such as a bed slat, thus produced.
• MDCEs Construction elements with cross sections as stated above, MDCEs, are widely used for instance in furniture and interior decoration. Such elements can be produced for instance from solid wood or plywood as well as from non-wood materials.
• One problem with production methods for producing MDCE is to produce such elements at a low cost with a low environmental impact and to produce an element with consistent, reliable and relatively uniform properties.
• One object of the present disclosure is therefore to provide a method for producing a medium-dimension construction element at a low cost and with reliable properties. This object is achieved by a method as defined in claim 1 . Then, in a method of the initially mentioned type, a plurality of planks, preferably wood planks, are assembled into a precursor block configuration, wherein the planks have a common general wood fiber direction. A precursor block is formed by gluing the planks of the precur sor block configuration to each other.
• An MDCE is formed by sawing the precursor block along a first plane, substantially parallel with the general wood fiber direction, and along a second plane, substantially parallel with the general wood fiber direction, wherein the first plane is at an angle with, preferably substantially perpendicular to, the second plane, and such that said at least one MDCE comprises material originat ing from at least two planks at any cross section along its length.
• a construction element with features from at least two planks are formed, which means that individual features, such as a knot in one of the planks, does not weaken the element to the same extent as in an element made from a single piece of solid wood.
• planks may be glued together face surface to face surface and a precursor block may be assembled from at least three parallel planks, more preferably at least four parallel planks, and still more preferably at least eight parallel planks.
• All planks in the plurality of planks may have face surfaces with the same width Wp across the length direction of the planks.
• at least some of the planks of the precursor block may comprise a joint, such as a butt joint or a finger joint, at a location along the length of the plank. If so, the joints of adjacent layers in the precursor block are preferably out of register with each other. This ensures that potentially weak points are spread out over the MDCE.
• the first plane may extend perpendicularly to glue layers formed when gluing the planks to each other.
• the MDCE may comprise material from at least three parallel planks in the precursor block.
• All the glue layers in an MDCE may be parallel, and all wood layers between two glue layers may consists of a single plank in a cross section along the length of the MDCE. This makes the MDCE more structurally robust when bent about an axis forming a normal to the glue layers.
• the moisture content of the planks may be in the range 8-12 % when measured in accordance with the standard EN 13183-1:2002.
• the planks have a thick ness Tp in the range 7-25 mm, typically 7-13 mm, and a width Wp in the range 75- 200 mm.
• planks in different layers may have different thicknesses.
• the planks may comprise wood selected from the group spruce, pine, aspen, beech, birch, eucalyptus, rubber wood, and mixtures thereof. Preferably at least 90% of the total weight of planks is selected from this group.
• a suitable glue resin for gluing the planks to each other may be selected from a group comprising polyvinyl acetate (PVAc), urea formaldehyde (UF), polyuretane (PUR), phenolic resin adhesive, and an isocyanate-based glue, such as emulsion polymer isocyanate (EPI), and mixtures of resins in this group.
• the sawing of the MDCE from the precursor may typically take place after completion of the glueing.
• the present disclosure also considers a medium-dimension construction element, MDCE, of wood, having an arbitrary length and having a width in the range 3-25 cm and a height in the range 0.5-4 cm.
• MDCEs are conceivable where the cross section is in the range 0.5-12 cm in both the height and width dimensions.
• the MDCE preferably comprises, in cross section, material originating from at least two planks, glued together.
• the MDCE comprises in each cross section along its length material from at least three planks, preferably at least four planks.
• the planes of glue layers formed when gluing the planks may be parallel to either of a flat- or an edge surface of the MDCE along the length thereof.
• the MDCE may have a rectangular cross section with a width Wm and a thickness Tm, the width Wm being preferably at least 50% greater than the thickness Tm, and the glue layers between the planks preferably extend in parallel with the thickness preferably in between opposing flat surfaces of the planks.
• the MDCE has a rectangular cross section with a width Wm and a thickness Tm, the glue layers between the planks extend in parallel with the thickness, and in a cross section, the wood in between two glue layers consists of a single plank.
• the present disclosure further considers a furniture component, such as a bed slat, comprising an MDCE as configured and/or produced as indicated above.
• Fig 1 illustrates the assembling of a precursor block configuration.
• Fig 2 shows the finished precursor block.
• Figs 3 and 4 illustrate the sawing of a precursor block into construction elements.
• Fig 5A and 5B show a construction element sawn from a precursor block
• fig 6 illustrates an example of a product built with such construction elements.
• the present disclosure relates to a method for producing a medium-dimension con struction element, MDCE, of wood.
• MDCE medium-dimension con struction element
• an MDCE is meant an elongated construction element with a cross section width in the range 3-25 cm and a cross section height in the range 0.5-4 cm.
• the length of the MDCE may be arbitrary but is usually a few meters or less, typically the length is 3.0 meters or less and longer than 0.2 m.
• Such elements may be useful for instance in furniture and interior decoration, with MDCEs used as bed slats being one typical example.
• an MDCE is produced by assembling a plurality of planks into a precursor block configuration, forming a precursor block by gluing the planks of the precursor block configuration to each other, and sawing the precursor block into a plurality of MDCE elements. This process is illustrated in figs 1-4.
• a plank 1 is here meant a thick, more or less parallelepiped-shaped wood board piece.
• the plank 1 has a length or longitudinal direction, in the direction the wood fibers generally extend, which length Lp usually is several times its width Wp and thickness Tp across that length direction.
• the cross section of the plank 1 may be quadratic, but more likely approximately rectangular, having narrower sides defining two edge surfaces 5 of the plank, and wider sides defining two face surfaces 7 of the plank. At each end of the plank there are end surfaces 9.
• Other terms than plank such as a wood board or a beam may be used.
• a non-rectangular cross section of the plank would be possible within the present disclosure, such as a rhomboidal one.
• a precursor block 3 is assembled from at least four parallel planks and more likely more than ten such planks.
• plank dimension would be 10 mm thick (Tp), meaning a width of the edge surface 5 of 10 mm, and 150 mm wide (Wp), meaning a width of the face surface 7 of 150 mm, and having a length (Lp) of a few meters.
• Plank pieces of shorter length e.g. of a length of 20 to 100 cm, may be used to fill spaces in a precursor block in an efficient manner in some cases. More generally, planks with a thickness Tp in the range 7-25 mm, and widths Wp in the range 75-200, such as 100- 150, mm are considered. As will be discussed, it may be advantageous to vary the thickness of the planks over the precursor block, typically to use thinner planks at the inner and outer layers of the stack of planks forming the precursor block.
• Suitable wood materials include relatively soft wood selected in the group comprising spruce, pine, aspen, beech, birch, and eucalyptus, rubber wood, and mixtures thereof, although other wood species can be considered as well.
• the planks may be dried to a relatively low moisture content, such as in the range between 8-12 % when measured in accordance with the standard EN 13183-1:2002, this being slightly lower than the moisture content at which wooden planks are usually traded in the tempered zone.
• the planks may be planed before being assembled.
• planks 1 When assembled into a precursor block configuration, as illustrated in fig 1 , the planks 1 may be placed face surface 7 to face surface 7, and it is in this interface between face surfaces 7 of adjacent planks 1 that glue is applied.
• glue usually takes place simultaneously with the assembling.
• planks can be joined in their length directions, as illustrated in fig 1. This can be done by as sembling and gluing together planks, end surface 9 to end surface 9, in the assemb ling phase, as illustrated in fig 1. Such joining of a straight end face to another straight end face is referred to as a butt joint 8, which has the advantage of requiring minimal preparation work.
• the planks can be joined beforehand to the desired length, in which case e.g. finger joints can also be used in combination with gluing.
• joints 8 When planks 1 are joined in their length directions, it is advantageous to avoid having such joints 8 close to each other, to increase the mechanical strength of the finished product.
• joints at laterally adjacent planks could be offset, for instance by at least 10 mm.
• the joints of adjacent planks in the precursor block may thus be out of register with each other
• the assembling can be made manually, but of course the as sembling task lends itself well to automation.
• glue is applied at the face surfaces 7 of the adjacent planks 1 where they are to be in contact with each other.
• the planks are then glued by applying some pressure to form the precursor block 11 illustrated in fig 2.
• the glue application may be carried out with a procedure well known in the art, for instance by rolling or spraying glue onto those surfaces.
• glue resins in a group comprising polyvinyl acetate (PVAc), urea formaldehyde (UF), polyuretane (PUR), phenolic resin adhesive, and an isocyanate-based glue, such as emulsion polymer isocyanate (EPI), and mixtures of resins in this group, are considered suitable.
• PVAc polyvinyl acetate
• U urea formaldehyde
• PUR polyuretane
• EPI emulsion polymer isocyanate
• a temperature typically in the range 15-70 degrees Celsius, is suitable for curing the glue, typically using a cold press, heated press plates or by a high-frequency press.
• the precursor block 11 may be pressed, during curing, in a direction perpendicular to the planes in which the glue extends, such that adjacent face surfaces 7 are pressed against each other, and for instance with a pressure of 5-20 kg/cm 2 .
• This precursor block 11 has the shape of a parallelepiped with rectangular cross section and may now be sawn into a number of construction elements. It is possible to form a plurality of precursor blocks 11 at the same time in a press, glue need not be applied between all layers of wood.
• the precursor block 11 is sawn into a plurality of MDCEs as illustrated in figs 3 and 4. As shown, a band saw 17 or a frame saw may typically be used for this purpose.
• the precursor block 11 is sawn at several locations and along first and second planes 10, 12. Those planes may be substantial ly parallel with the general wood fiber direction, and, typically, the first and second planes are substantially perpendicular to each other, although this is not necessary. For instance, a rhomboid cross section can be formed when sawing the precursor.
• the precursor block 11 is further sawn in such a way that a resulting MDCE comprises material originating from at least two parallel planks along most of its length, or more preferably along its entire length. As shown in fig 2, the first planes 10 along which the precursor is sawn are parallel with the flat surfaces 7 (cf.
• each piece comprise material from at least 3-4 planks.
• An individual plank may be locally weak, for instance at a knot in that plank. However, as that plank is joined usually with two or more other planks at each weak location this is compensated for to a large extent.
• the second planes 12 along which the precursor is sawn, may be parallel with the flat side of the precursor block 11 , coinciding with the edge surfaces 5 of the planks (cf. fig 1).
• one of the planes 12 along which the precursor is sawn extends perpendicularly to glue layers formed when gluing the planks to each other.
• the MDCE comprises material from at least three or four parallel planks in the precursor block. This means that a knot, for instance, in one of the planks will locally decrease the strength of the MDCE to an even lesser extent.
• Fig 5A illustrates an MDCE 15 having a rectangular cross section with a width Wm and a thickness Tm.
• width W is at least 50% greater than the thickness Tm, and the glue layers extend in parallel with the thickness, although many other embodiments are possible.
• the MDCE is preferably oriented such that the glue layers extend vertically as illustrated in the cross section of fig 5B. It is preferred that in the cross section each layer of wood in between the layers of glue comprise material from one plank only along the thickness Tm, as illustrated in fig 5B. Thus in each cross section, the glue layers extend only in one direction. As shown in the cross section of fig 5B, if the beam is bent about an axis extending horizontally, no significant shear forces will be applied across the glue layers which improve the structural strength.
• Fig 6 illustrates one example of use of an MDCE 15 produced as described earlier in the framework of a bed 19 where such an MDCE is used as a furniture component in the form of a bed slat.
• planks with varied thicknesses in the precursor block may be provided.
• the planks in the end of the stacks may be thinner to produce MDCEs with uniform thickness being built from a uniform number of planks.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Forests & Forestry (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)

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• 2022
  • 2022-06-22 WO PCT/SE2022/050627 patent/WO2022271077A1/en active Application Filing
  • 2022-06-22 EP EP22828872.6A patent/EP4359181A1/de active Pending

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