A method for forming an engagement groove in a wood-based panel

Abstract

The invention relates to a method for forming an engagement groove (4) comprising at least one longitudinal portion (54, 60) in a wood-based panel (6). The method comprises the steps of removing material locally from an edge region (46) adjacent an edge (24) of the wood-based panel (6) to form a cavity (49). The cavity (49) is sized to allow that at least a portion of the at least one longitudinal portion (54, 60) of the engagement groove (4) ends in the cavity (49) at a distance from the edge (24) of the wood-based panel (6) in order to minimize any formation of shavings at the edge (24) of the wood-based panel (6) resulting from the forming of the engagement groove (4). The method further comprises the step of forming the engagement groove (4) in the wood-based panel (6), wherein the step of removing material locally from the edge region (46) to form the cavity (49) and the step of forming the engagement groove (4) are aligned to make the at least a portion of the longitudinal portion (54, 60) of the engagement groove (4) end in the cavity (49).

Description

[0001] A method for forming an engagement groove in a wood-based panel

[0002] TECHNICAL FIELD

[0003] The invention relates to a method for forming an engagement groove in a wood-based panel. The invention is further related to a machine for forming an engagement groove in a wood-based panel.

[0004] The wood-based panel may comprise a flat wood-based core and a decorative and / or hard top layer arranged on a main side surface of the flat wood-based core. The woodbased core of the panel may be made of fibre board like MDF (Medium Density Fibre board) or HDF (High Density Fibre board) or plywood or particle board. The decorative top layer may be a plastic coating such as Melamine.

[0005] Wood-based panels are used in different types of pieces of furniture, such as cabinets, cupboards, bookshelves and wardrobes.

[0006] In order to assemble such pieces of furniture, there is a desire to attach two rectangular panels to each other so that they extend perpendicularly relative to one another. A first one of the rectangular panels may then comprise a longitudinal groove extending in a main face of the panel and adjacent an edge of the panel. A second one of the rectangular panels may be provided with a longitudinal projection extending adjacent an edge of the panel or forming the edge, wherein the projection and the groove have complimentary shaped crosswise geometries for engagement. In assembly, the first rectangular panel may be held in a vertical orientation, wherein the second rectangular panel is moved from above and downwards so that an end of the longitudinal projection enters an end of the longitudinal groove and so that the longitudinal projection is slid along the longitudinal groove. Especially, the groove may be designed with a so-called undercut, which creates conditions for an easy assembly and stable furniture.

[0007] More specifically, a pair of two panels may be arranged in parallel with each other and at a distance from each other for forming side walls. A further panel, which may be of a different character than the side walls, may be attached to each one of the side walls for forming a back wall. The back wall may then be slid from above and downwards so that its opposite edges simultaneously engage with engagement grooves in the side walls facing each other. Such engagement grooves may be formed by different material removing methods, such as milling and sawing. There is however a challenge to produce the engagement grooves in the panels so that the panels are aesthetically attractive. More specifically, shavings or chips formed during the cutting should be transported away in a proper and suitable way.

[0008] SUMMARY

[0009] One object of the invention is to achieve a method for forming an engagement groove in a wood-based panel that creates conditions for an aesthetically desirable finish of the panel, especially adjacent the ends of the engagement groove.

[0010] The object is achieved by a method according to claim 1. Thus, it is achieved by a method for forming an engagement groove comprising at least one longitudinal portion in a woodbased panel, comprising the steps of removing material locally from an edge region adjacent an edge of the wood-based panel to form a cavity, wherein the cavity is sized to allow that at least a portion of the at least one longitudinal portion of the engagement groove ends in the cavity at a distance from the edge of the wood-based panel in order to minimize any formation of shavings at the edge of the wood-based panel resulting from the forming of the engagement groove, and forming the engagement groove in the woodbased panel, wherein the step of removing material locally from the edge region to form the cavity and the step of forming the engagement groove are aligned to make the at least a portion of the longitudinal portion of the engagement groove end in the cavity.

[0011] The method creates conditions for solving the problem of any remaining shavings formed at the edge of the panel where a cutting tool that creates the at least one longitudinal portion of the engagement groove exits the panel.

[0012] The term “edge” is here used for the flat surface bridging two main flat surfaces of the panel, ie the edge defines a thickness of the panel.

[0013] The term “edge region” is here used for defining a region of the panel adjacent the edge that is intended for removal of material. More specifically, material is removed from the panel so that the flat edge surface is interrupted by the cavity that is formed by the removed material. Further, the term “locally” defines that the cavity has a length in parallel with a longitudinal direction of the engagement groove that is substantially shorter than a length of the wood-based panel and / or the length of the engagement groove and especially that the extension of the cavity is limited to being adjacent the edge.

[0014] According to one example, the engagement groove has an extension all the way between the first-mentioned edge and a further edge of the wood-based panel opposite the first- mentioned edge. According to a further example, the engagement groove has an extension along a straight line. According to a further example, the engagement groove has a constant shape and size in a cross section along its length direction. According to a further example, the engagement groove is provided in one of the opposite main flat surfaces of the panel and adjacent an edge bridging the distance between the opposite main flat surfaces of the panel. According to a further example, the engagement groove is in parallel with the edge bridging the distance between the opposite main flat surfaces of the panel.

[0015] The term “longitudinal portion of the engagement groove” is here used for defining a portion of the engagement groove that has a significant length in a longitudinal direction of the engagement groove. According to one example, the longitudinal portion of the engagement groove has substantially the same length as the engagement groove. According to a further example, the longitudinal portion of the engagement groove has a constant shape and size in a cross section along its length direction. According to a further example, the longitudinal portion of the engagement groove may be formed as an undercut, ie a portion of the engagement groove in communication with a longitudinal base portion of the engagement groove and spaced from the main flat surface of the panel. In other words, the undercut may be formed by cutting away material at a distance from the main flat surface of the panel so as to leave an overhanging portion. According to a further example, the longitudinal base portion of the engagement groove may be formed by means of a first cutting tool in a first cutting step and the longitudinal portion of the engagement groove forming the undercut may be formed by means of a second cutting tool in a second cutting step.

[0016] The wording “at least a portion of the at least one longitudinal portion of the engagement groove ends in the cavity” indicates that in cross section at least a portion of the longitudinal portion of the engagement groove ends in the cavity. In other words, at least a portion of a cutting surface of a cutting tool that creates the at least one longitudinal portion of the engagement groove ends in the cavity. According to a preferred example, in cross section a significant portion of the longitudinal portion of the engagement groove ends in the cavity. According to a further preferred example, in cross section the entire longitudinal portion of the engagement groove ends in the cavity.

[0017] According to one example, the cavity that is formed by the removal of material has a certain shape and size in a cross section in a plane in parallel with a plane of the edge of the wood-based panel that is at least substantially as large as a cross section of the longitudinal portion of the engagement groove perpendicular to a longitudinal direction of the engagement groove. More particularly, the shape and size of the cavity in said cross section is sufficient for a cutting tool creating the longitudinal portion of the engagement groove to end up with its cutting surface within the cavity in its entirety in cross section. Further, the cavity has a certain length extension in parallel with a longitudinal direction of the engagement groove so that the longitudinal portion of the engagement groove ends at a distance from the edge of the wood-based panel, wherein the distance is set by an inner surface of the cavity opposite the edge. It creates further conditions for minimizing any remaining shavings protruding from the edge of the wood based panel after the forming of the engagement groove.

[0018] A size of the cavity may differ depending on a character and operation of a tool that is used for the removal of material. According to one example, the cavity has an extension of up to 20 mm from the edge in a direction perpendicularly relative to the edge. According to a further example, the cavity has an extension of about 15 mm from the edge (for example in case a rotatably arranged saw blade is used). According to another example, the cavity has an extension of 0.5-5 mm from the edge (for example in case a drill, punch and / or milling tool is used). Especially, in case an edge strip is attached to the edge of the wood-based panel, the cavity has an extension at least as large as a thickness of the edge strip.

[0019] Accordingly, the edge region is cleared from material locally in the step of removing material from the edge of the wood-based panel. Accordingly, the cavity has a certain cross section perpendicular to a designated extension direction of the engagement groove, wherein the cross section of the cavity is sized larger than a cross section of at least the longitudinal portion of the engagement groove that is cut by means of a cutting surface of the cutting tool for encompassing the longitudinal portion of the engagement groove. Since the cutting surface of the cutting tool will end up in the cavity, the longitudinal portion of the engagement groove will not reach all the way to the edge of the wood-based panel.

[0020] The term “aligned” is here used for defining that the step of removing material locally from the edge region to form the cavity and the step of forming the engagement groove result in that the at least a portion of the longitudinal portion of the engagement groove ends in the cavity. In other words, the term “aligned” indicates a certain structural relationship between the cavity and the longitudinal portion of the engagement groove after the processing steps. Accordingly, the step of removing material locally from the edge region to form the cavity and the step of forming the engagement groove may be performed in consecutive order, e.g. in sequence.

[0021] According to one example, the wood-based panel has a flat rectangular shape, wherein it extends in a flat plane. Accordingly, the wood-based panel comprises a first rectangular main flat surface and second rectangular main flat surface facing in opposite directions. The first main flat surface and the second main flat surface are arranged in planes parallel with each other and spaced from each other. Accordingly, the wood-based panel has a uniform thickness. Further, the wood-based panel comprises edges bridging the distance between the first main flat surface and the second main flat surface. More specifically, the edges comprise a first pair of parallel, straight and spaced edges and a second pair of parallel, straight and spaced edges that are perpendicular relative to the first pair of edges. Each one of the edges extends in a plane perpendicularly to the first main flat surface and the second main flat surface.

[0022] According to one example, the engagement groove is formed as a longitudinal groove with a linear extension extending in a main face of the panel in parallel with and adjacent one of the edges of the panel. According to one example, at least a portion of the engagement groove is formed by a cutting tool engaging with the panel at a first edge, being moved along the adjacent edge and exiting the wood-based panel at a second edge opposite the first edge.

[0023] According to one embodiment example, the method comprises the step of preparing the edge region of the wood-based panel by the local removal of material and thereby forming the cavity prior to the forming of the longitudinal portion of the engagement groove. In this way, the edge region is cleared from material in advance so that at least a portion of a cutting tool forming the longitudinal portion of the engagement groove may exit the panel in a void with a reduced risk of any remaining shavings protruding from the edge. Such a preparation of the edge region may be performed by means of a punch or a cutting tool, such as a drill, a saw blade or a milling tool. The wording “removal of material” comprises both cutting material away from the panel and forming a void / depression by compacting the wood material.

[0024] In other words, the cutting surface of the cutting arrangement will exit the material of the wood-based panel at a distance from the edge, wherein the distance is defined by a size of the cavity. According to one example, the cutting arrangement is adapted for engaging the cutting surface in the material of the wood-based panel to a constant depth in a straight line along a main part of the wood-based panel, wherein the cutting surface will exit the material when it reaches the cavity in close proximity to the edge.

[0025] According to one alternative or complement to the last-mentioned embodiment example, the method comprises the step of locally removing the material from the edge region of the wood-based panel and thereby forming the cavity after the forming of the longitudinal portion of the engagement groove. In this way, the edge region is cleared from material after that a cutting tool forming the longitudinal portion of the engagement groove has exited the panel, wherein any remaining shavings protruding from the edge resulting from the cutting operation are removed. Such finalization of the edge region may be performed by means of a cutting tool, such as a punch, a drill, a saw blade or a milling tool.

[0026] According to one example, the cavity is created in a two step procedure comprising a first step of locally removing material from the edge region of the wood-based panel before the forming of the longitudinal portion of the engagement groove in order to reduce the risk of shavings resulting from the forming of the longitudinal portion of the engagement groove and a second step of locally removing material from the edge region of the wood-based panel after the forming of the longitudinal portion of the engagement groove in order to do away with any shavings resulting from the forming of the longitudinal portion of the engagement groove.

[0027] According to one example, the cavity is created in a plural step procedure, wherein at least two different tools / means are used for the creation of the cavity. According to one further embodiment example, a length of the cavity, as seen in a lengthwise direction of the longitudinal portion of the engagement groove, is less than 10%, preferably less than 5%, still more preferably less than 2.5%, of a length of the longitudinal portion of the engagement groove.

[0028] According to one further embodiment example, a length of the cavity, as seen in a lengthwise direction of the longitudinal portion of the engagement groove, is 1-40 mm, preferably 2-25 mm, and more preferably 3-20 mm.

[0029] According to one further embodiment example, a width of the cavity, as seen a direction being perpendicular to a length-wise direction of the longitudinal portion of the engagement groove, is larger than a width of the longitudinal portion of the engagement groove, and / or wherein the width of the cavity is 1-15 mm, preferably 2-12 mm, and more preferably 2-10 mm.

[0030] According to one further embodiment example, a depth of the cavity, as seen in a direction of thickness of the wood-based panel, is larger than a depth of the longitudinal portion of the engagement groove, and / or wherein the depth of the cavity is 4-25 mm, preferably 6-20 mm.

[0031] According to one further embodiment example, the step of removing the material locally from the edge region of the wood-based panel to form the cavity is performed while the wood-based panel is stationary. It creates conditions for achieving the removal of material in the edge region with a high accuracy. It may be performed before the forming of the engagement groove or after the formation of the engagement groove.

[0032] In the example of using a punch for the removal of material in the edge region, the punch is preferably moved in line with an intended extension of the engagement groove. In other words, the punch may be moved perpendicularly relative to an extension plane of the edge. In other words, the punch may be moved in parallel with an extension plane of the main face of the panel.

[0033] According to one alternative, the punch is moved perpendicularly to an intended extension of the engagement groove. The punch is adapted for creating material deformation by means of compression, ie by means of mechanical indentation. Such compression results in that the panel material adjacent the depression / recess has a higher density and thereby higher hardness. According to an alternative, the punch is adapted to cut away a portion of the panel and bring it away from the panel to form the cavity. The punch may have a cross section shape and size corresponding to a cross section shape and size of the engagement groove. According to an alternative, the punch may have a cross section shape and size that is different from a cross section shape and size of the engagement groove. Especially, the punch may have a cross section size substantially larger than a cross section size of the engagement groove. As a complement or alternative, the punch may have a cross section shape that is different from a cross section shape of the engagement groove. According to one example, the punch may have a rounded surface adapted for engagement with the panel for creating a correspondingly rounded depression / recess in the panel.

[0034] According to one further embodiment example, the punch is moved from a retracted position to an extended position in line with an intended extension of the engagement groove so that the punch in its extended position engages with the wood-based panel.

[0035] In the example of using a drill for the removal of material in the edge region, according to one example, the drill is moved in a transverse direction relative to an intended extension of the engagement groove. In other words, the drill may be moved perpendicularly relative to an extension plane of the main face of the panel. In other words, the drill may be moved in parallel with an extension plane of the edge and in line with the edge.

[0036] In the example of using a drill for the removal of material in the edge region, according to a further example, the drill is moved in line with an intended extension of the engagement groove. In other words, the drill may be moved perpendicularly relative to an extension plane of the edge. In other words, the drill may be moved in parallel with an extension plane of the main face of the panel.

[0037] In the example of using a rotatably arranged saw blade for the removal of material in the edge region, the saw blade is preferably moved with its axis of rotation in a transverse direction and more especially perpendicularly relative to an intended extension of the engagement groove. In the example of using a milling tool for the removal of material in the edge region, the milling tool may be arranged with its axis of rotation in a transverse direction relative to and more especially perpendicularly relative to an intended extension of the engagement groove.

[0038] According to one further embodiment example, the method comprises the step of locally removing the material at the edge region of the wood-based panel while the wood-based panel is moving. It creates conditions for a high production pace. Accordingly, the step of removing the material at the edge region of the wood-based panel and the step of forming the engagement groove may be performed as two consecutive steps as the wood-based panel is moving in a non-interrupted way, possibly with a constant speed.

[0039] According to one example, a speed of the conveyor for forwarding the wood-based panel is in an interval of 40-80 meter / minute. In the case that material is removed at the edge region of the wood-based panel simultaneously with the wood-based panel being forwarded, the speed of the conveyor may be in an interval of 40-60 meter / minute. On the other hand, in the case that material is removed from the edge region of the wood-based panel while the wood-based panel is stationary, the engagement groove may be formed with a speed of the conveyor for forwarding the wood-based panel in an interval of 60-80 meter / minute.

[0040] According to one example, a drill may be arranged with its axis of rotation arranged perpendicularly to a forwarding direction of a conveyor. Further, the panels may be forwarded on the conveyor past the drill in a way that the edge adapted for material removal faces the drill. Accordingly, the panels may be turned 90° before and / or after a position of the drill. Further, the drill may be movably arranged along the conveyor and a movement of the drill may be synchronized with a speed of the conveyor so that the drill is moved in parallel with the panel at the same speed when the drill is rotated and moved perpendicularly to the panel edge for material removal.

[0041] According to one further embodiment example, the method comprises the step of forwarding the wood-based panel past the cutting tool, wherein the cutting tool is moved in a transverse direction relative to a forwarding direction from a retracted position to an extended position during the forwarding of the wood-based panel so that the cutting tool engages with the wood-based panel and cuts material from the edge at a rear part of the wood-based panel at the edge region of the edge designated for the engagement groove.

[0042] The wording that “the cutting tool engages with the wood-based panel and cuts material from a rear edge of the wood-based panel at an edge region of the edge designated for the engagement groove” means that the cutting tool prepares the rear edge at a desired position before the engagement groove is formed therein.

[0043] Accordingly, the movement of the cutting tool in the transverse direction relative to the forwarding direction from the retracted position to the extended position is performed when a main part of the wood-based panel has past the cutting tool. More specifically, the cutting tool may be arranged in a stationary state during the forwarding of the main part of the wood-based panel past the cutting tool.

[0044] The fact that the method is adapted so that that the cutting arrangement exits the woodbased panel in the edge region of removed material creates conditions for significantly less remaining shavings at the end of the engagement groove.

[0045] Accordingly, the cutting tool is adapted to be moved from the retracted position to the extended position so that its cutting periphery extends across a plane defined by a main flat surface of the panel at the edge of the panel.

[0046] According to one example, the cutting tool is moved in a continuous way from the retracted position to the extended position.

[0047] Accordingly, by simultaneously forwarding the wood-based panel past the cutting tool and moving the cutting tool in a transverse direction relative to the forwarding direction from the retracted position to the extended position during the forwarding of the wood-based panel, the cutting tool will cut away material from the rear edge of the wood-based panel forming an inclined cut surface.

[0048] According to one further example, the cutting tool is moved in a reciprocating manner from the retracted position to the extended position and back to the retracted position. In other words, the cutting tool may be withdrawn to the retracted position directly after having reached its extended position. By matching the speed of the reciprocating movement to the speed of a conveyor and the distance between forwarded panels, the cutting tool may reach the retracted position again after cutting a rear edge of a first panel before a front edge of a next panel reaches the position of the cutting tool. Accordingly, the cutting tool is retracted to an initial position for cutting a next incoming wood-based panel forwarded in the forwarding direction. According to one example, the cutting tool is then maintained in the retracted position until a next wood-based panel to a main extent has passed the cutting tool in the forwarding direction for performing the reciprocating motion at the rear edge of the panel. According to one alternative, the cutting tool may be moved so that it cuts a next incoming wood-based panel as it is moved from the extended position back to the retracted position. Accordingly, every second wood-based panel is cut as the cutting tool is moved from the retracted position to the extended position and every second panel is cut as the cutting tool is moved from the extended position to the retracted position.

[0049] According to one example, the wood-based panel is continuously forwarded on a conveyor past the cutting tool. The wood-based panel may be positioned with one of its main flat surfaces on the conveyor. Thus, the wood-based panel may have a horizontal orientation during the forwarding on the conveyor. According to one example, the woodbased panel is moving with a constant speed past the cutting tool.

[0050] According to one example, the cutting tool is arranged below a path of the wood-based panel as it is moving on the conveyor. Accordingly, the cutting tool is adapted to be moved in a vertical direction upwards from the retracted position to the extended position.

[0051] According to a further development of the last-mentioned embodiment example, the method comprises the step of moving the cutting tool in a linear path perpendicularly relative to the forwarding direction from the retracted position to the extended position during the forwarding of the wood-based panel past the cutting tool. According to one example, the cutting tool is mounted on a movably arranged linear guide means that is adapted to engage with a complimentary shaped stationary linear guide means. The cutting tool may be a rotating cutting tool, wherein an axis of rotation is moved during rotation of the cutting tool so that a cutting surface of the cutting tool is moved from the retracted position to the extended position. According to one further embodiment example, the engagement groove is formed to have a linear extension in parallel with the forwarding direction. According to one example, the wood-based panel has a rectangular shape, wherein it comprises parallel edges that form a front edge and rear edge in the forwarding direction. Further, the panel comprises two further parallel edges that form lateral edges. Accordingly, the engagement groove is formed in parallel with one of the parallel lateral edges.

[0052] According to one further embodiment example, the engagement groove is formed in a main surface of the wood-based panel by means of the cutting arrangement engaging with the wood-based panel in a direction from a front edge of the wood-based panel to the rear edge of the wood-based panel in the forwarding direction.

[0053] According to one further embodiment example, the method comprises the step of detecting a position of the edge of the wood-based panel and matching the movement of the cutting tool between the retracted position and the extended position to the position of the edge as the wood-based panel passes the cutting tool.

[0054] According to one further embodiment example, wherein the forming of the longitudinal portion of the engagement groove is achieved by moving the wood-based panel relative to a cutting arrangement in a way that at least one cutting surface of the cutting arrangement engages with the wood-based panel and that the cutting surface crosses the cavity at the edge region of removed material during the relative movement.

[0055] According to one further embodiment example, the method comprises the steps of forming the engagement groove in the wood-based panel by means of a cutting arrangement and forwarding the wood-based panel past the cutting arrangement positioned downstream of the cutting tool in the forwarding direction so that a cutting edge of the cutting arrangement engages with the wood-based panel in a starting point distant from the edge region of removed material and exits the wood-based panel in the edge region of removed material. According to a preferred example, the engagement groove is formed in a main surface of the wood-based panel by means of the cutting arrangement engaging with the wood-based panel from a front edge of the wood-based panel to the rear edge of the wood-based panel.

[0056] According to one further embodiment example, the cutting arrangement comprises a further cutting tool for forming a longitudinal base portion of the engagement groove. According to a further development, the further cutting tool of the cutting arrangement comprises a rotating saw blade arranged with its axis of rotation perpendicularly to the forwarding direction and in parallel with a main surface of the wood-based panel, wherein the axis of rotation of the rotating saw blade is maintained at a predefined distance in relation to the main surface of the wood-based panel during the complete forwarding of the wood-based panel past the rotating saw blade for forming the longitudinal base portion of the engagement groove.

[0057] According to one example, the longitudinal base portion forms a significant portion of the engagement groove in a cross section. According to one example, the longitudinal base portion of the engagement groove forms a linear groove with a constant depth and constant width along its extension.

[0058] According to one further embodiment example, the cutting arrangement comprises an under-cutting device arranged downstream of the further cutting tool, wherein an undercut is cut in a side wall of the longitudinal base portion of the engagement groove by means of the under-cutting device, preferably the under-cutting device comprises at least one second cutting surface, wherein the undercut ends in the cavity. Accordingly, the cutting arrangement may comprise two consecutive cutting stations, a first station for forming the longitudinal base portion of the engagement groove and a second station positioned downstream of the first cutting station for forming the undercut.

[0059] According to one further embodiment example, material is removed from the edge region so that the cavity formed by the removed material has a larger extension in a transverse direction of the engagement groove than the undercut so that an end of the undercut in its entirety is located within the edge region of removed material. It creates further conditions for minimizing any remaining shavings protruding from the edge.

[0060] According to one further embodiment example, the cutting device of the cutting arrangement comprises at least one stationary cutting head, wherein the wood-based panel is moving so that a support part of the stationary cutting head enters an open end of the longitudinal base portion of the engagement groove and a cutting part of the stationary cutting head, that extends transversally relative to the support part, engages with the wood-based panel adjacent the longitudinal base portion of the engagement groove. Accordingly, the cutting device is adapted to remove material from at least one of the lateral surfaces defining the longitudinal base portion of the engagement groove.

[0061] According to a further development of the last-mentioned embodiment example, the cutting device of the cutting arrangement comprises a plurality of stationary cutting heads arranged in a spaced relationship in the forwarding direction, wherein the stationary cutting heads have cutting surfaces displaced in the transverse direction relative to the forwarding direction for successively cutting material during forwarding of the wood-based panel for forming the undercut. It creates conditions for transporting shavings formed during the cutting away in a proper way.

[0062] According to one further embodiment example, an edge strip is attached to the rear edge of the wood-based panel in a step prior to that the wood-based panel is moving past the cutting tool and that the movement of the cutting tool from the retracted position to the extended position is performed so that it cuts throughout a thickness of the edge strip. The edge strip may be formed as a decorative feature, wherein a rough surface of the wood-based core may be covered. The edge strip may be formed in a plastic material. Accordingly, material is removed also from the edge strip as the cutting tool is moved from the retracted position to the extended position.

[0063] According to one further embodiment example, the method comprises the step of creating a pre-cut groove in the wood-based panel along a line designated for the engagement groove.

[0064] According to one further embodiment example, the method comprises the step of creating the pre-cut groove in the wood-based panel by means of the same cutting tool that cuts material from the rear edge of the wood-based panel for forming the cavity.

[0065] According to one further embodiment example, the method comprises the step of maintaining the cutting tool stationary in the retracted position for cutting the pre-cut groove in the wood-based panel along a main portion of the line designated for the engagement groove and moving the cutting tool so that the cutting tool is moved from the retracted position to the extended position at the rear end of the wood-based panel for cutting material from the rear edge of the wood-based panel. According to one example, the cutting tool comprises a peripheral cutting surface adapted for cutting the pre-cut groove and a shoulder surface adjacent the peripheral cutting surface and at a smaller diameter relative to the peripheral cutting surface. The cutting tool is adapted so that a radial distance between the peripheral cutting surface and the shoulder surface is sufficient for the shoulder surface to engage with the wood-based panel only at the rear edge of the wood-based panel as the cutting tool is moved from the retracted position to the extended position. In other words, the shoulder surface is inactive during the movement of the wood-based panel along the main portion of the line designated for the engagement groove.

[0066] According to one further embodiment example, the wood-based panel comprises a core of a chip panel material and a layer of a material of a significantly higher hardness than the chip panel material provided on a main surface of the chip panel material core, wherein the pre-cut groove is cut throughout the hard surface layer of the wood-based panel.

[0067] According to one further embodiment example, the method comprises the step of creating the engagement groove by means of the cutting arrangement in parallel with the pre-cut groove and at least partly overlapping with the pre-cut groove in a way that the engagement groove has a larger extent into the wood-based panel than the pre-cut groove. More specifically, an extension of the engagement groove may coincide with the pre-cut groove. Accordingly, the pre-cut groove prepares the panel before it is machined by means of the cutting tool for forming the longitudinal base portion of the engagement groove.

[0068] A further object of the invention is to achieve a machine for forming an engagement groove in a wood-based panel that creates conditions for a high productivity while still achieving an aesthetically desirable finish of the groove, especially adjacent an end of the engagement groove.

[0069] The object is achieved by a machine according to claim 38. Thus, it is achieved by a machine for forming an engagement groove in a wood-based panel, wherein the machine comprises a cutting tool and a conveyor for forwarding the wood-based panel in a forwarding direction past the cutting tool, wherein the cutting tool is adapted to be moved in a transverse direction relative to the forwarding direction from a retracted position to an extended position during the forwarding of the wood-based panel so that the cutting tool may engage with the wood-based panel and cut material from a rear edge of the woodbased panel at an edge region of the edge designated for the engagement groove so that a cavity is formed, wherein the cavity may be sized to allow that at least a portion of a longitudinal portion of the engagement groove ends in the cavity at a distance from the edge of the wood-based panel, and wherein the machine comprises a cutting arrangement positioned downstream of the cutting tool in the forwarding direction, wherein the conveyor is adapted for forwarding the wood-based panel past the cutting arrangement for forming the engagement groove in the wood-based panel by the cutting arrangement during the forwarding of the wood-based panel in that the cutting arrangement may engage with the wood-based panel in a starting point distant from the edge region of removed material and exit the wood-based panel in the cavity so that the at least a portion of the at least one longitudinal portion of the engagement groove ends in the cavity at a distance from the edge of the wood-based panel.

[0070] Further advantages and advantageous features of the invention are disclosed in the following description and in the dependent claims.

[0071] BRIEF DESCRIPTION OF THE DRAWINGS

[0072] With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

[0073] In the drawings:

[0074] Fig. 1 is a schematic perspective view from above of a machine for forming an engagement groove in a wood-based panel,

[0075] Fig. 2 is a cross sectional view of a panel along the cut A-A in fig. 1,

[0076] Fig. 3 is a partly cut perspective view from above of a panel for being machined,

[0077] Fig. 4 is a schematic view of a cutting tool in the machine for material removal of the panel from below,

[0078] Fig. 5 is a schematic view of the cutting tool and panel in fig. 4,

[0079] Fig. 6 is a similar view as in fig. 1 indicating a cut B-B,

[0080] Fig. 7 is a cross sectional view of a panel along the cut B-B in fig. 6,

[0081] Fig. 8 is a schematic view of a cutting tool in the machine for material removal of the panel from below, wherein a transverse movement of the cutting tool is indicated, Fig. 9 is a perspective partly cut view of an edge of the panel resulting from the material removal of the cutting tool in fig. 8,

[0082] Fig. 10 is a similar view as in fig. 1 indicating a cut C-C,

[0083] Fig. 11 is a cross sectional view of a panel along the cut C-C in fig. 10,

[0084] Fig. 12 is a perspective partly cut view of the edge of the panel resulting from the material removal of a further cutting tool,

[0085] Fig. 13 is a perspective view of a stationary under-cutting device in the machine,

[0086] Fig. 14 is a view front view of the stationary under-cutting device in fig. 13 in the forwarding direction of the conveyor,

[0087] Fig. 15 is a similar view as in fig. 1 indicating a cut D-D,

[0088] Fig. 16 is a cross sectional view of a panel along the cut D-D in fig. 15,

[0089] Fig. 17a is a perspective partly cut view of the edge of the panel resulting from the material removal of the under-cutting device in fig. 13,

[0090] Fig. 17b is a view in a cross section in parallel with the edge of the panel,

[0091] Fig. 17c is a perspective view of the panel resulting from the material removal by means of the under-cutting device in fig. 13,

[0092] Fig. 18 is a perspective view of assembly of a frame for a kitchen cabinet comprising the wood-based panel in fig. 17a,

[0093] Fig. 19 is a schematic perspective view from above of a milling tool for material removal as an alternative to the saw blade according to the first embodiment in fig. 1 ,

[0094] Fig. 20A-E are schematic perspective views from above of method steps involving a drill for material removal as an alternative to the saw blade according to the first embodiment in fig. 1, and

[0095] Fig. 21A-D are schematic perspective views from above of method steps involving a punch for material removal as an alternative to the saw blade according to the first embodiment in fig. 1.

[0096] DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0097] Fig. 1 is a schematic perspective view from above of a machine 2 for forming an engagement groove 4 (see fig. 17a, 17b and 17c) in a wood-based panel 6. The ultimate purpose of the engagement groove 4 may be to engage with a further panel, as will be described hereinafter (see fig. 18). The machine 2 comprises a conveyor 8 for forwarding wood-based panels 6 one after the other in a forwarding direction 10. The conveyor 8 comprises a horizontally oriented upper surface 12 for forwarding the wood-based panels 6 in a horizontal plane along a straight line. The conveyor 8 comprises one or several belts 9 that define the upper surface 12. The conveyor 8 further comprises a holder 11 that is arranged above the belt 9 and adapted to maintain a pressure on the wood-based panels 6 during forwarding. The holder 11 comprises a stationary structure 13 that rotationally holds at least one set of rollers 15 arranged in line in parallel with the forwarding direction. The rollers 15 are adapted to contact the wood-based panels 6 from above during forwarding.

[0098] Turning now to fig. 3. The wood-based panel 6 has a rectangular shape, wherein it comprises a first main flat surface 14 and second main flat surface 16 facing in opposite directions. The first main flat surface 14 and the second main flat surface 16 are arranged in planes parallel with each other and spaced from each other. Accordingly, the woodbased panel 6 has a uniform thickness. Further, the wood-based panel 6 comprises parallel first and second straight and spaced longitudinal edges 18, 20. Further, the woodbased panel comprises parallel third and fourth straight and spaced lateral edges 22, 24. The third and fourth straight lateral edges 22, 24 are perpendicular to the first and second straight longitudinal edges 18, 20. Each one of the first, second, third and fourth straight edges 18, 20, 22, 24 extends perpendicularly to the first main flat surface 14 and the second main flat surface 16.

[0099] Fig. 2 is a cross sectional view of the wood-based panel 6 along the cut A-A in fig. 1. The wood-based panel 6 comprises a wood-based core 23 and a decorative top layer 26. The core 23 of the panel may be made of fibre board like MDF (Medium Density Fibre board) or HDF (High Density Fibre board) or plywood. The decorative top layer 26 may be a plastic coating such as Melamine. The decorative top layer 26 is provided on each one of the first main flat surface 14 and the second main flat surface 16. The decorative top layer 26 may further be provided on at least one of the edges 18, 20, 22, 24. Further, the woodbased panel 6 comprises an edge strip 28, see fig. 9, attached to the fourth lateral edge 24 of the wood-based panel 6. The edge strip 28 has an extension covering substantially the complete edge 24 of the wood-based panel 6. The edge strip 28 may be of a plastic material.

[0100] Turning now again to fig. 1. Each one of the wood-based panels 6 is positioned with one of its main flat surfaces 16 on the upper surface 12 of the conveyor 8. Thus, the woodbased panel has a horizontal orientation during the forwarding on the conveyor 8. According to one example, the wood-based panels 6 are forwarded with a constant speed on the conveyor 8. Further, the wood-based panels 6 are arranged on the conveyor 8 in a way that their parallel first and second straight longitudinal edges 18, 20 are in parallel relative to the forwarding direction 10. Accordingly, the wood-based panels 6 are arranged on the conveyor 8 in a way that their parallel third and fourth lateral edges 22, 24 are arranged perpendicular with the forwarding direction 10. Thus, the third and fourth lateral edges 22, 24 form a front edge and rear edge in the forwarding direction.

[0101] The machine 2 comprises a cutting tool 30 in the form of a rotating saw blade 130 with a periphery defining a circular shape. The cutting tool 30 is arranged to be movable in a transverse direction relative to the forwarding direction 10 from a retracted position to an extended position. More specifically, the cutting tool 30 is arranged so that its rotational axis 38 is below the upper surface 12 of the conveyor 8 in the retracted position. More specifically, the cutting tool 30 is arranged to be movable in a perpendicular direction relative to the forwarding direction 10 from the retracted position to the extended position. More specifically, the cutting tool 30 is arranged to be movable vertically upwards from the retracted position to the extended position. More specifically, the cutting tool 30 is moved so that a cutting surface 32 of the cutting tool is below the upper surface 12 of the conveyor 8 in the retracted position and above the upper surface 12 of the conveyor 8 in the extended position. Accordingly, the cutting tool 30 is arranged to engage with the wood-based panel 6 via the cutting surface 32 in the extended position.

[0102] The machine 2 comprises guide means 34, 36 for guiding the cutting tool 30 during the movement between the retracted position and the extended position. More specifically, the cutting tool 30 is mounted on a movably arranged linear guide means 34 that is adapted to engage with a complimentary shaped stationary linear guide means 36. More specifically, an axis of rotation 38 of the cutting tool 30 is moved during rotation of the cutting tool 30 so that the cutting surface 32 of the cutting tool 30 is moved from the retracted position to the extended position. The machine 2 comprises a first vertical post 37 arranged adjacent the conveyor 8, wherein the first vertical post 37 comprises the stationary linear guide means 36.

[0103] The machine 2 further comprises a motor 40 that is rotationally operationally connected to the cutting tool 30 for rotating the cutting tool. The motor 40 is attached to the movably arranged linear guide means 34 for being moved vertically in a linear fashion. The motor 40 is adapted to be moved along the stationary linear guide means 36 by means of an actuator 25.

[0104] The machine 2 further comprises a sensor 27 arranged to monitor the wood-based panels 6 as they are forwarded on the conveyor 8. More specifically, the sensor 27 is adapted for detecting a position of the rear edge 24 of the wood-based panel 6. The sensor 27 may be an optical sensor. The machine 2 further comprises a controller 29, that is operationally connected to the sensor 27 for receiving a signal with information of the position of the rear edge 24 of the wood-based panel 6. The controller 29 receives further input of operational parameters, such as speed of the conveyor, see arrow 47. The controller 29 comprises software for controlling the movement of the cutting tool 30 in response to the input signals. More specifically, the controller 29 is operationally connected to the actuator 25 for controlling its movement. Accordingly, the controller is adapted for matching the movement of the cutting tool 30 from the retracted position to the extended position based on the position of the rear edge as the wood-based panel 6 passes the cutting tool 30.

[0105] Turning now to fig. 4 and fig. 5, the cutting tool 30 comprises an additional cutting surface 33 that is arranged adjacent the cutting surface 32. More specifically, the additional cutting surface 33 forms a radially outermost periphery of the cutting tool 30. The cutting surface 32 is arranged axially adjacent the additional cutting surface 33 at a radial distance from its periphery. More specifically, the cutting surface 32 forms a shoulder on one side of the additional cutting surface 33 in the axial direction of the cutting tool 30.

[0106] More specifically, the rotational axis 38 of the cutting tool 30 is adapted to be stationary arranged in the vertical direction in the retracted position that allows the additional cutting surface 33 to engage with the wood-based panel 6 for creating a pre-cut groove 35 in the wood-based panel 6, while the cutting surface 32 is not in engagement with the woodbased panel 6 during a main part of the wood-based panel. More specifically, the pre-cut groove 35 is formed along a straight line designated for the engagement groove 4. More specifically, the pre-cut groove 35 is formed all the way from the front edge 22 of the wood-based panel.

[0107] More specifically, the cutting tool 30 has such a cross section shape that the cutting surface 32 is in parallel with its rotational axis. Further, the cutting tool 30 has such a cross section shape that the additional cutting surface 33 is in parallel with its rotational axis. Further, the additional cutting surface 33 is spaced axially from the cutting surface 32 and an inclined surface bridges the distance between them. A similarly shaped inclined surface is arranged on an opposite side of the additional cutting surface 33. Accordingly, the cutting tool 30 has a trapezoidal external shape. It may however be noted that the cutting tool may be designed without the inclined surfaces, for example with planar surfaces extending perpendicularly to the rotational axis on either side of the additional cutting surface 33.

[0108] Fig. 6 is a similar view of the machine 2 as in fig. 1 indicating a cut B-B and Fig. 7 is a cross sectional view of the wood-based panel 6 along the cut B-B in fig. 6.

[0109] Fig. 8 is a schematic view from below of the cutting tool 30 in the machine 2 for material removal of the rear edge 24 of the wood-based panel 6, wherein a vertical movement of the cutting tool 30 upwards is indicated with an arrow 39. Accordingly, the cutting tool 30 is maintained stationary in the retracted position for cutting the pre-cut groove 35 in the wood-based panel 6 with a constant depth along a main portion of a line designated for the engagement groove 4. Further, the cutting tool 30 is moved upwards from the retracted position to the extended position at the rear end of the wood-based panel 6 for cutting material from the rear edge 24 of the wood-based panel. More specifically, the cutting surface 32 of the cutting tool 30 engages with the wood-based panel 6 and cuts material from the rear edge 24 of the wood-based panel at an edge region 46 adjacent the edge 24 so that a cavity 49 is formed, see fig. 9. Fig. 9 is a perspective partly cut view of the edge 24 of the wood-based panel resulting from the material removal of the cutting tool in fig. 8. The cavity 49 that is created by the cutting surfaces 32, 33 has a width Wc, length Lc and depth De . The cavity 49 has a constant width, wherein an extension of the cavity 49 in its height direction increases towards the edge 24.

[0110] Accordingly, the pre-cut groove 35 in the wood-based panel 6 is formed by means of the same cutting tool 30 that cuts material from the rear edge 24 of the wood-based panel 6 for forming the cavity 49.

[0111] The wood-based panel 6 comprises an optional layer 26 of a material of a significantly higher hardness than the chip panel material in the core 23 of a chip panel material of the wood-based panel 6, see fig. 5. The hard surface layer 26 is provided on a main surface of the chip panel material core 23, wherein the pre-cut groove 35 is cut throughout the hard surface layer 26 of the wood-based panel by means of the additional cutting surface 33. The pre-cut groove 35 is cut so that it does not engage with the core 23 of chip panel material, or at least does not engage with the core 23 of chip panel material to a significant extent.

[0112] Turning now to fig. 1 again. The machine 2 further comprises a cutting arrangement 42 positioned downstream of the cutting tool 30 in the forwarding direction of the conveyor 8. The cutting arrangement 42 is adapted to form the engagement groove 4 in the woodbased panel 6 during forwarding of the wood-based panel 6 past the cutting arrangement 42.

[0113] The method further comprises the step of forwarding the wood-based panel 6 past the cutting arrangement 42, wherein the engagement groove 4 is formed in the wood-based panel 6 by the cutting arrangement 42 during the forwarding of the wood-based panel 6 in that the cutting arrangement 42 engages with the wood-based panel 6 in a starting point 44 distant from the edge region 46 of removed material, see fig. 9 and exits the woodbased panel in the region 46 of removed material. The starting point 44 is positioned at the front edge 22 of the wood-based panel 6 in the forwarding direction.

[0114] The cutting arrangement 42 comprises two sections; a first section 48 comprising a further cutting tool 52 for forming a longitudinal base portion 54 of the engagement groove 4, see fig. 11 , and a second section 56 arranged downstream of the first section 48, wherein the second section 56 comprises an under-cutting device 58 for forming a further longitudinal portion in the form of an undercut 60, see fig. 16, in the longitudinal base portion 54 of the engagement groove 4. More specifically, the rotating cutting tool 52 is adjustably fixed vertically in the machine 2.

[0115] Turning now to fig. 11. The longitudinal base portion 54 forms a significant portion of the engagement groove 4 in a cross section. The longitudinal base portion 54 of the engagement groove forms a linear groove with a constant depth and constant width along its extension. More specifically, the longitudinal base portion 54 of the engagement groove is cut so that it is located in parallel with and coinciding with the pre-cut groove 35. More specifically, the rotating cutting tool 52 of the cutting arrangement 42 comprises the rotating saw blade 130, see figure 8, arranged with its axis of rotation perpendicularly to the forwarding direction and in parallel with a main surface of the wood-based panel 6, wherein the axis of rotation of the rotating saw blade is maintained at a predefined distance in relation to the main surface of the wood-based panel 6 during the complete forwarding of the wood-based panel past the rotating saw blade for forming the longitudinal base portion 54 of the engagement groove 4. More specifically, the rotating saw blade comprises a cutting surface 53 at its radial outer periphery. The first section 48 of the cutting arrangement 42 comprises a motor 41 that is rotationally operationally connected to the cutting tool 52 for rotating the cutting tool. The motor 41 is attached to a movably arranged linear guide means 43 for being moved vertically by means on a vertical post 45 adjacent the conveyor 8. In this way, the cutting tool 52 may be set in different vertical positions depending on the application, the character of the wood-based panel to be cut etc. In contrast to the upstream cutting tool 30, the downstream cutting tool 52 is adapted to be vertically stationary arranged during the complete cutting operation.

[0116] The cutting tool 30 is designed and operated in a way that the cavity 49 is sized to allow that at least one longitudinal portion 54, 60 of the engagement groove 4 ends in the cavity 49 at a distance from the edge 24 of the wood-based panel 6. More specifically, the cavity 49 is sized to allow that at least the longitudinal portion 60 forming the undercut ends in the cavity 49 at a distance from the edge 24 of the wood-based panel 6.

[0117] Fig. 12 is a perspective partly cut view of the edge of the panel 6 resulting from the material removal of the rotating cutting tool 52. The cavity 49 that is created by the vertical movement of the cutting tool 30 upwards as explained above comprises a first volume cut away by means of the first cutting surface 32 of the cutting tool 30 and a second volume cut away by means of the additional cutting surface 33 of the cutting tool 30. More specifically, the cavity 49 (see fig. 9) is sized so that the cutting surface 53 of the rotating saw blade 52 passes the cavity 49 during the movement of the panel 6. More specifically, the cutting surface 53 of the rotating saw blade 52 passes in its entirety the cavity 49 of removed material. Accordingly, the longitudinal base portion 54 of the engagement groove 4 ends in the cavity 49 of removed material.

[0118] Fig. 13 is a perspective view of a stationary under-cutting device 58 in the machine 2. Fig. 14 is a view front view of the stationary under-cutting device 58 in fig. 13 in the forwarding direction of the conveyor 8. The under-cutting device 58 comprises a plurality of stationary cutting heads 62, 64 arranged in a spaced relationship in the forwarding direction. The stationary cutting heads 62, 64 are rigidly arranged on a support piece 65. A support part 66, 68 of the respective stationary cutting head 62, 64 is adapted to enter an open end of the longitudinal base portion 54 of the engagement groove 4 at the front edge 22 of the wood-based panel 6 and a cutting part 70, 72 of the stationary cutting head, that extends transversally relative to the support part 66, 68, engages with the wood-based panel adjacent the longitudinal base portion 54 of the engagement groove 4. Further, the stationary cutting heads 62, 64 have cutting surfaces 67, 69 displaced in the transverse direction relative to the forwarding direction for successively cutting material during forwarding of the wood-based panel 6 for forming the longitudinal portion (undercut) 60. In other words, a width of the cutting heads 62, 64 increase from the first cutting head 62 to a last cutting head 64 in the forwarding direction. The cutting heads 62, 64 have cutting edges at a height corresponding with the position of an undercut groove 60 to be formed in the wood-based panel 6.

[0119] After the first cutting step of the cutting arrangement 42, the wood-based panel 6 will have a longitudinal straight groove 35, formed by the rotating saw blade 52. The longitudinal straight groove 35 has a rectangular cross section with one open side, as seen in an end view. In the second step, the wood-based panel 6 will pass over the under-cutting device 58, wherein the under-cutting device 58 is received in the longitudinal straight groove 35 to form the undercut 60.

[0120] The first cutting head 62 in the row of cutting heads is the first one to enter the longitudinal straight groove 35 of the wood-based panel 6. The last cutting head 64 in the row is the last cutting head to enter the longitudinal straight groove 35 of the wood-based panel 6. The number of cutting heads 62, 64 may vary. The cutting width of the cutting heads 62, 64 increases from the first cutting head 62 to the last cutting head 64. Thus, the width of the undercut groove 60 is increased somewhat for each passing cutting head 62, 64.

[0121] The undercut 60 that is cut in the longitudinal base portion 54 of the engagement groove 4 by means of the under-cutting device 58 ends in the cavity 49. Accordingly, the undercutting device 58 is adapted to remove material from at least one of the lateral surfaces 74, 76 defining the longitudinal base portion 54 of the engagement groove 4, see fig. 11. Further, the cutting tool 30 is adapted to remove material from the edge region 46 to such an extent that the cavity 49 formed by the removed material has a larger extension in a transverse direction of the engagement groove 4 than the undercut 60 so that an end of the undercut in its entirety ends up within the cavity 49.

[0122] Fig. 17a is a perspective partly cut view of the edge of the panel 6 resulting from the material removal of the stationary under-cutting device 58. The cavity 49 of removed material is sized so that the cutting surfaces 67, 69 of the stationary under-cutting device 58 passes through the cavity 49 during the movement of the panel 6. Referring now also to fig. 17b and fig. 17c, the cavity 49 has a depth De which is deeper than the depth Dg of the undercut 60. Furthermore, the cavity 49 has a width Wc which is wider than the width Wg of the undercut 60. More specifically, the cutting surfaces 67, 69 of the stationary under-cutting device 58 end up in their entirety in cross section in the cavity 49. In other words, the exit of the undercut 60 is embedded within the width Wc and depth De of the cavity 49. Accordingly, the undercut 60 ends in the cavity 49. Thereby, any shavings formed when cutting the undercut 60 will be formed inside the cavity 49 without reaching the exterior at the rear edge 24. Fig. 17b is a view in a cross section in parallel with the edge of the panel, wherein the cavity 49 may be viewed in further detail.

[0123] Fig. 17c is a perspective view of the panel resulting from the material removal by means of the under-cutting device 58 in fig. 13. A length of the undercut 60, and also the total length of the engagement groove 4 when finalized, as illustrated in Figs. 17a-17b, is denoted Lg.

[0124] In other words, the cutting arrangement 42 is adapted for forming a longitudinal straight groove 35 in a first step, wherein the longitudinal straight groove 35 is formed into an undercut groove 60 in a second step.

[0125] As each cutting head 62, 64 only takes away a small amount of material, the relative travel speed of the wood-based panel past the under-cutting device 58 can be held relatively high without extensive heating of the wood-based panel 6 or the under-cutting device 58.

[0126] Fig. 18 is a perspective view of assembly of a frame 100 for a kitchen cabinet comprising two wood-based panels 6, each provided with the undercut engagement groove 4. More specifically, the undercut engagement groove 4 extend adjacent and in parallel with an edge of the panel. The two wood-based panels 6 are arranged in parallel with each other and at a distance from each other for forming side walls, wherein the undercut engagement grooves 4 face each other. The frame 100 further comprises a bottom wall 102, wherein the two wood-based panels 6 are attached to the bottom wall 102 in a way that they extend perpendicularly with regard to the bottom wall 102. A further panel 104, which may be of a different character than the side walls 6, may be attached to each one of the side walls for forming a back wall. The back wall 104 is slid from above, see arrow 105 and downwards so that its opposite edges 106, 108 simultaneously engage with the engagement grooves 4 in the side walls 6. The undercut engagement grooves 4 and the opposite edges 106, 108 have complimentary shaped crosswise geometries for engagement. Fig. 18 further shows a top wall 110 that is adapted to be arranged on top of and attached to the side walls 6 in a state in parallel with the bottom wall 102.

[0127] Fig. 19 is a schematic perspective view from above of a milling tool 230 for material removal as an alternative to the saw blade according to the first embodiment in fig. 1. Similar to the embodiment of the rotating saw blade, the milling tool 230 is arranged for removing the material at the edge region 46 of the wood-based panel 6 while the woodbased panel is moving to form the cavity 49. The milling tool 230 is arranged with its axis of rotation 138 in a transverse direction relative to an intended extension of the engagement groove 4. More specifically, the milling tool 230 is arranged with its axis of rotation 138 perpendicularly relative to the forwarding direction 10 of the conveyor 8. The milling tool 230 is operationally connected to the motor 40 for rotating the milling tool. Further, the motor 40 is movably arranged up and down, see arrow 39, by means of the actuator 25.

[0128] Fig. 20A-E are schematic perspective views from above of consecutive method steps involving a drill 330 for material removal as an alternative to the saw blade according to the first embodiment in fig. 1. In contrast to the embodiment of the rotating saw blade, the step of removing the material from the edge region 46 of the wood-based panel 6 to form the cavity 49 is performed while the wood-based panel 6 is stationary. According to this example, the method comprises the step of preparing the edge region 46 of the woodbased panel by the removal of material to form the cavity 49 in a step prior to the forming of the engagement groove 4. Further, the drill 330 is moved in a transverse direction relative to an intended extension of the engagement groove 4. More specifically, the drill 330 is arranged for operation with its axis of rotation perpendicularly relative to a main plane of the wood-based panel 6. Fig. 20A shows the drill 330 in an initial, retracted position below the wood-based panel 6. Fig. 20B shows the drill 330 in an extended position, wherein it extends into the wood-based panel 6. Fig. 20C shows the drill 330 in the retracted position again, after having formed the cavity 49. Fig. 20 D shows the precut groove 35 ending in the edge region 46 of removed material. Fig. 20 E shows the undercut groove 4 ending in the edge region 46 of removed material.

[0129] According to an alternative to the arrangement of the drill described above with reference to fig. 20A-E, the drill is adapted for material removal for forming the cavity 49 during the forwarding on the conveyor 8. The drill may be arranged adjacent the conveyor with its axis of rotation perpendicularly to a forwarding direction of the conveyor 8. Further, the drill may be movably arranged in parallel with the forwarding direction of the conveyor 8 and the speed of the drill may be synchronized to be the same as the speed of the conveyor so that the drill is moved in parallel with the panel and at the same speed as the panel when the drill is moved towards the panel for removal of material. Further, the panels may be turned 90° before reaching the position of the drill so that the edge of the panel assigned for material removal faces the drill. Further, the panels may be turned 90° back again after having passe the position of the drill so that the edge of the panel with the cavity 49 faces in the forwarding direction of the conveyor again.

[0130] Fig. 21A-D are schematic perspective views from above of method steps involving a punch 430 for material removal for forming a cavity 49 as an alternative to the saw blade according to the first embodiment in fig. 1. The punch 430 is adapted for creating material deformation by means of compression, i.e. by means of mechanical indentation or cutting out material. The punch is adapted for creating material deformation by means of compression, ie by means of mechanical indentation. Such compression results in that the panel material adjacent the depression / recess has a higher density and thereby higher hardness. According to an alternative, the punch is hollow and adapted to cut away a portion of the panel and bring it away from the panel to form the cavity. In other words, the punch comprises a thin wall defining its peripheral edge, wherein the thin wall defines a hollow interior.

[0131] In contrast to the embodiment of the rotating saw blade, the step of removing the material from the edge region 46 of the wood-based panel 6 is performed while the wood-based panel 6 is stationary. According to this example, the method comprises the step of preparing the edge region 46 of the wood-based panel by the removal of material in a step prior to the forming of the engagement groove 4. Further, the punch 430 is moved in parallel with and in-line with an intended extension of the engagement groove 4. More specifically, the punch 430 is arranged for movement in parallel with a main plane of the wood-based panel 6. Fig. 21A shows the punch 430 in an initial, retracted position next to the wood-based panel 6. Fig. 21 B shows the punch 430 in an extended position, wherein it extends into the wood-based panel 6. Fig. 21 C shows the punch 430 in the retracted position again, and the cavity 49 formed thereby. Fig. 21 D shows the undercut groove 4 ending in the edge region 46 of removed material.

[0132] The punch 430 has a cross section shape and size substantially the same as a cross section shape and size of the engagement groove. According to an alternative, the punch may have a cross section size somewhat larger than a cross section size of the engagement groove. As a complement or alternative, the punch may have a cross section shape that is different from a cross section shape of the engagement groove. According to one example, the punch may have a spherical surface adapted for engagement with the panel for creating a correspondingly spherical depression / recess in the panel.

[0133] According to an alternative to the methods shown in fig. 20A-E and fig. 21A-D, the method comprises the step of removing the material from the edge region 46 of the wood-based panel to form the cavity 49 in a step after the forming of the engagement groove 4.

[0134] According to a further alternative to the methods shown in fig. 20A-E and fig. 21A-D, the method comprises the step of removing the material from the edge region of the woodbased panel by means of a drill, wherein the drill is arranged with its axis of rotation in-line with an intended extension of the engagement groove. More specifically, the drill is arranged with its axis of rotation in parallel with a main plane of the wood-based panel. In other words, the drill is arranged with its axis of rotation perpendicularly to the edge of the wood-based panel. Accordingly, the drill may be moved from an initial, retracted position next to the wood-based panel to an extended position, wherein it extends into the woodbased panel.

[0135] It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

[0136] According to the example described above in association with figures 1-17c, one single tool, that is the saw blade 130, is designed to create a cavity at the edge region of the panel that is sufficiently sized for both receiving the longitudinal base portion 54 of the engagement groove, that is created by the rotating cutting tool 52 (saw blade) and the undercut 60 that is created by the under-cutting device 58. According to an alternative, the cavity creating tool may be designed and operated for creating a cavity that is sized only for receiving one of the longitudinal base portion 54 and the undercut 60 (and not the other one). For example, depending on the tools used, creating the undercut 60 may result in significantly more shavings or chips than creating the longitudinal base portion 54 of the engagement groove, wherein it may be sufficient to create a cavity sized specifically for receiving the undercut 60.

[0137] According to the example described above in association with figures 1-17c, one single tool, that is the cutting tool 30 is designed to create both a pre-cut groove 35 in the woodbased panel 6 and the cavity 49. According to an alternative, the cavity is created by a tool specifically designed and operated only for creating the cavity.

[0138] The example described above in association with figure 18 regards a cabinet, wherein opposite edges of a back wall engage with undercut engagement grooves in two opposite side walls. According to one alternative or complement, a piece of furniture may be designed so that a different panel than a back wall may engage with an undercut engagement groove formed in a panel. According to one example, a bottom wall in a cabinet (or other type of furniture) may be designed with at least one undercut engagement groove, wherein at least one side wall and preferably both side walls may be adapted to engage with the undercut engagement groove(s).

[0139] According to a further alternative, a piece of furniture may be designed so that a metal rail is adapted to be received in an undercut engagement groove in a wood-based panel. According to a further development, such a metal rail may be adapted for forming an attachment for another furniture part. According to one example, the piece of furniture may be a wardrobe.

Claims

CLAIMS1. A method for forming an engagement groove (4) comprising at least one longitudinal portion (54, 60) in a wood-based panel (6), comprising the steps of removing material locally from an edge region (46) adjacent an edge (24) of the wood-based panel (6) to form a cavity (49), wherein the cavity (49) is sized to allow that at least a portion of the at least one longitudinal portion (54, 60) of the engagement groove (4) ends in the cavity (49) at a distance from the edge (24) of the wood-based panel (6) in order to minimize any formation of shavings at the edge (24) of the wood-based panel (6) resulting from the forming of the engagement groove (4), and forming the engagement groove (4) in the woodbased panel (6), wherein the step of removing material locally from the edge region (46) to form the cavity (49) and the step of forming the engagement groove (4) are aligned to make the at least a portion of the longitudinal portion (54, 60) of the engagement groove (4) end in the cavity (49).

2. A method according to claim 1 , wherein the method comprises the step of preparing the edge region (46) of the wood-based panel (6) by the local removal of material and thereby forming the cavity (49) prior to the forming of the longitudinal portion (54, 60) of the engagement groove (4).

3. A method according to any of the preceding claims, wherein the method comprises the step of removing the material locally from the edge region (46) of the wood-based panel (6) and thereby forming the cavity (49) after the forming of the longitudinal portion (54, 60) of the engagement groove (4).

4. A method according to any one of the preceding claims, wherein a length (Lc) of the cavity (49), as seen in a length-wise direction of the longitudinal portion (54, 60) of the engagement groove (4), is less than 10%, preferably less than 5%, still more preferably less than 2.5%, of a length (Lg) of the longitudinal portion (54, 60) of the engagement groove (4).

5. A method according to any one of the preceding claims, wherein a length (Lc) of the cavity (49), as seen in a length-wise direction of the longitudinal portion (54,60) of the engagement groove (4) is 1-40 mm, preferably 2-25 mm, and more preferably 3-20 mm.

6. A method according to any one of the preceding claims, wherein a width (Wc) of the cavity (49), as seen in a direction being perpendicular to a length-wise direction of the longitudinal portion (54, 60) of the engagement groove (4), is larger than a width (Wg) of the longitudinal portion (54, 60) of the engagement groove (4), and / or wherein the width (Wc) of the cavity (49) is 1-15 mm, preferably 2-12 mm, and more preferably 2-10 mm.

7. A method according to any one of the preceding claims, wherein a depth (De) of the cavity (49), as seen in a direction of thickness of the wood-based panel (6), is larger than a depth (Dg) of the longitudinal portion (54, 60) of the engagement groove (4), and / or wherein the depth (De) of the cavity (49) is 4-25 mm, preferably 6-20 mm.

8. A method according to any one of the preceding claims, wherein the step of removing the material locally from the edge region (46) of the wood-based panel (6) to form the cavity (49) is performed while the wood-based panel (6) is stationary.

9. A method according to any one of the preceding claims, wherein the step of removing the material locally from the edge region (46) of the wood-based panel (6) to form the cavity (49) is performed by means of a punch (430).

10. A method according to claim 9, wherein the punch (430) is moved from a retracted position to an extended position in line with an intended extension of the engagement groove (4) so that the punch (430) in its extended position engages with the wood-based panel (6).

11. A method according to any one of the preceding claims, wherein the step of removing the material locally at the edge region (46) of the wood-based panel (6) to form the cavity (49) is performed by means of a cutting tool (30).

12. A method according to claim 11 , wherein the cutting tool (30) comprises a drill (330).

13. A method according to claim 12, wherein the drill (330) is moved from a retracted position to an extended position in a transverse direction relative to an intended extension of the engagement groove (4) so that the drill (330) in the extended position engages with the wood-based panel (6).

14. A method according to any of claims 11-13, wherein the cutting tool (30) comprises a rotatably arranged saw blade (130).

15. A method according to claim 14, wherein the rotatably arranged saw blade (130) is arranged with its axis of rotation (38) in a transverse direction relative to an intended extension of the engagement groove (4).

16. A method according to any of claims 11-15, wherein the cutting tool comprises a milling tool (230).

17. A method according to claim 16, wherein the milling tool (230) is arranged with its axis of rotation (138) extending in a transverse direction relative to an intended extension of the engagement groove (4).

18. A method according to any one of claims 11-17 when dependant on any one of claims 1-3, comprising the step of removing the material at the edge region (46) of the wood-based panel (6) while the wood-based panel (6) is moving.

19. A method according to claim 18, wherein the method comprises the step of forwarding the wood-based panel (6) past the cutting tool (30), wherein the cutting tool (30) is moved in a transverse direction relative to a forwarding direction (10) from a retracted position to an extended position during the forwarding of the wood-based panel (6) so that the cutting tool (30) engages with the wood-based panel (6) and cuts material from the edge (24) at a rear part of the wood-based panel (6) at the edge region (46) of the edge designated for the engagement groove (4).

20. A method according to claim 19, wherein the method comprises the step of moving the cutting tool (30) in a linear path perpendicularly relative to the forwarding direction (10) from the retracted position to the extended position during the forwarding of the wood-based panel (6) past the cutting tool (30).

21. A method according to claim 19 or 20, wherein the method comprises the step of moving the cutting tool (30) back from the extended position to the retracted position for cutting a next incoming wood-based panel (6) forwarded in the forwarding direction.

22. A method according to any one of claims 19-21, wherein the method comprises the step of detecting a position of the edge (24) of the wood-based panel (6) and matching the movement of the cutting tool (30) between the retracted position and the extended position to the position of the edge (24) as the wood-based panel (6) passes the cutting tool (30).

23. A method according to any one of the preceding claims, wherein the forming of the longitudinal portion (54, 60) of the engagement groove (4) is achieved by moving the wood-based panel (6) relative to a cutting arrangement (42) in a way that at least one cutting surface (53, 67, 69) of the cutting arrangement (42) engages with the wood-based panel (6) and that the cutting surface (53, 67, 69) crosses the cavity (49) of removed material at the edge region (46) during the relative movement.

24. A method according to claim 23, wherein the engagement groove (4) is formed in a main surface (16) of the wood-based panel (6) by means of the cutting arrangement (42) engaging with the wood-based panel from a front edge (22) of the wood-based panel to the rear edge (24) of the wood-based panel.

25. A method according to any one of claims 23-24, wherein the cutting arrangement (42) comprises a further cutting tool (52) for forming a longitudinal base portion (54) of the engagement groove (4).

26. A method according to claim 25, wherein the further cutting tool (52) of the cutting arrangement (42) comprises a rotating saw blade arranged with its axis of rotation perpendicularly to the forwarding direction and in parallel with a main surface (16) of the wood-based panel (6), wherein the axis of rotation of the rotating saw blade is maintained at a predefined distance in relation to the main surface of the woodbased panel during the complete forwarding of the wood-based panel past therotating saw blade, wherein the rotating saw blade comprises a first cutting surface(53) for forming the longitudinal base portion (54) of the engagement groove (4).

27. A method according to claim 25 or 26, wherein the cutting arrangement (42) comprises an under-cutting device (58) arranged downstream of the further cutting tool (52), comprising the step of forming the longitudinal portion (60) of the engagement groove (4) as an undercut (60) in the longitudinal base portion (54) of the engagement groove (4) by means of the under-cutting device (58), preferably the under-cutting device (58) comprises at least one second cutting surface (67, 69), wherein the undercut (60) ends in the cavity (49).

28. A method according to claim 27, wherein material is removed from the edge region (46) so that the cavity (49) formed by the removed material has a larger extension in a transverse direction of the engagement groove (4) than the undercut (60) so that an end of the undercut in its entirety is located within the cavity (49).

29. A method according to claim 27 or 28, wherein the under-cutting device (58) of the cutting arrangement (42) comprises at least one stationary cutting head (62, 64), wherein the wood-based panel (6) is moving so that a support part (66, 68) of the stationary cutting head (62, 64) enters an open end of the longitudinal base portion(54) of the engagement groove (4) and a cutting part (70, 72) of the stationary cutting head, that extends transversally relative to the support part, provided with the second cutting surface (67, 69) engages with the wood-based panel (6) adjacent the longitudinal base portion (54) of the engagement groove (4).

30. A method according to claim 29, wherein the under-cutting device (58) of the cutting arrangement (42) comprises a plurality of stationary cutting heads (62, 64) arranged in a spaced relationship in the forwarding direction (10), wherein the stationary cutting heads (62, 64) have the second cutting surfaces (67, 69) displaced in the transverse direction relative to the forwarding direction for successively cutting material during forwarding of the wood-based panel (6) for forming the undercut (60).

31. A method according to any one of claims 23-30, comprising the step of forwarding the wood-based panel (6) past the cutting arrangement (42) positioned downstream of the cutting tool (30) in the forwarding direction so that a cuttingedge of the cutting arrangement (42) engages with the wood-based panel in a starting point distant from the edge region (46) of removed material and exits the wood-based panel in the cavity (49).

32. A method according to any preceding claim, wherein the wood-based panel (6) comprises a core (23) of a chip panel material and a layer (26) of a material of a significantly higher hardness than the chip panel material provided on a main surface of the chip panel material core, wherein the method comprises the step of creating a pre-cut groove (35) throughout the hard surface layer (26) of the woodbased panel (6) along a line designated for the engagement groove (4).

33. A method according to claim 32 when dependant on any one of claims 11-22, wherein the method comprises the step of creating the pre-cut groove (35) in the wood-based panel (6) by means of the same cutting tool (30) that cuts material from the rear edge (24) of the wood-based panel (6).

34. A method according to claim 33, wherein the method comprises the step of maintaining the cutting tool (30) stationary in the retracted position for cutting the pre-cut groove (35) in the wood-based panel (6) along a main portion of the line designated for the engagement groove (4) and moving the cutting tool (30) so that the cutting tool is moved from the retracted position to the extended position at the rear end of the wood-based panel for cutting material from the rear edge (24) of the wood-based panel to form the cavity (49).

35. A method according to any one of claims 23-31 and any one of claims 32-34, wherein the method comprises the step of creating the engagement groove (4) by means of the cutting arrangement (42) in parallel with the pre-cut groove (35) and at least partly overlapping with the pre-cut groove in a way that the engagement groove (4) has a larger extent into the wood-based panel (6) than the pre-cut groove (35).

36. A method according to any one of the preceding claims, wherein the engagement groove (4) is formed to have a linear extension.

37. A method according to any one of the preceding claims, wherein an edge strip (28) is attached to the edge (24) of the wood-based panel (6) in a step prior toremoving material to form the cavity (49) at the edge region (46) of the edge (24) of the wood-based panel and that the removal of material is performed throughout a thickness of the edge strip (28).

38. A machine (2) for forming an engagement groove (4) in a wood-based panel (6), wherein the machine comprises a cutting tool (30) and a conveyor (8) for forwarding the wood-based panel (6) in a forwarding direction (10) past the cutting tool (30), wherein the cutting tool (30) is adapted to be moved in a transverse direction relative to the forwarding direction (10) from a retracted position to an extended position during the forwarding of the wood-based panel (6) so that the cutting tool (30) may engage with the wood-based panel and cut material from a rear edge (24) of the wood-based panel (6) at an edge region (46) so that a cavity (49) is formed, wherein the cavity (49) may be sized to allow that at least a portion of at least one longitudinal portion (54, 60) of the engagement groove (4) ends in the cavity (49) at a distance from the edge (24) of the wood-based panel (6), and wherein the machine (2) comprises a cutting arrangement (42) positioned downstream of the cutting tool (30) in the forwarding direction (10), wherein the conveyor (8) is adapted for forwarding the wood-based panel (6) past the cutting arrangement (42) for forming the engagement groove (4) in the wood-based panel by the cutting arrangement (42) during the forwarding of the wood-based panel in that the cutting arrangement (42) may engage with the wood-based panel in a starting point distant from the cavity (49) formed by material removed at the edge region (46) and exit the wood-based panel in the cavity (49) so that the at least a portion of the longitudinal portion (54, 60) of the engagement groove (4) ends in the cavity (49) at a distance from the edge (24) of the wood-based panel (6).

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