Method for edge-banding panels and an edge-banding head capable of carrying out the method

Abstract

A method is described for covering a panel edge by applying a covering tape to the edge, with the steps of - loading a segment of tape onto an edge-banding head by installing an accumulation of curved tape on the edge-banding head; - moving the edge-banding head parallel to the edge and simultaneously applying the segment of tape to the edge by picking up tape from the accumulation. Thanks to the method the tape can be laid without it dangling from the edge-banding head which applies it.

Description

[0001] The present invention relates to a method for edge-banding panels and an edge-banding head capable of performing the method.

[0002] For edge-banding panels to be used in furniture construction, taken here as an example, a CNC machine is known in which the panel is machined in a stationary and horizontal position using a multi-tool spindle and an edge-banding head. The edge-banding head is fed by a tape which it then applies to the edge of the panel as a covering. As the tape is applied, its tail protrudes from the edge-banding head and hangs in the air like a whip around the panel and the CNC machine, causing safety and jamming problems. Especially for large panels, the length of the tape is several meters, and the probability that the "flying" tape will sooner or later get caught somewhere or gets scratched before assembly is very high.

[0003] The main object of the invention is to improve the current state of the art.

[0004] Another object is to provide a method for edge-banding panels in which the applied tape is less likely to jam and / or be damaged.

[0005] Another object is to create an edge-banding head capable of implementing the method.

[0006] These and other objects are achieved by the attached claims; advantageous technical features are defined in the dependent claims.

[0007] A method is proposed for covering a panel edge by applying a covering tape to the edge, with the steps of loading a segment of tape onto an edge-banding head by installing an accumulation of curved tape on the edge-banding head (the loaded tape is folded on the edge-banding head to concentrate it in a space smaller than its linear length); moving the edge-banding head parallel to the edge and simultaneously applying the tape segment to the edge by taking tape from the accumulation.

[0008] As the tape is loaded onto the edge-banding head, the tape is deflected and / or forced to change direction so that it is constrained to follow a curved path and thus form an accumulation of curved tape. The accumulation is compact and has a maximum size that is less than the linear length of the loaded tape, e.g. 3 to 20 times smaller, in particular about 10 times smaller.

[0009] The accumulation of curved tape has the advantage that the tape no longer protrudes from the edge-banding head as it is carried onto the panel or deposited on it. The tape is stored and compacted on the edge-banding head according to a pattern and therefore does not get in the way or become damaged before or during application. Thanks to this method, the tape can be laid without dangling or flapping from the edge-banding head that applies it.

[0010] The accumulation may be used up to lay a single edge, i.e. the application device applies the length of tape to one edge of the panel until the accumulation is depleted, or tape is taken from the accumulation to cover a plurality of edges.

[0011] In a variant that favors processing speed, an accumulation of curved tape already formed may be loaded onto the edge-banding head, i.e. a segment of tape already configured as an accumulation of curved tape is transferred to the edge-banding head.

[0012] In a different variant, which favors less complexity and greater flexibility of the system, the accumulation is formed on the edge-banding head during the loading of the tape onto the edge-banding head, e.g. starting from a straight tape and e.g. taken from a reel.

[0013] Preferably, the accumulation of curved tape is created by directing the tape segment into a curved guide located on the edge-banding head, wherein the guide defines a winding (i.e. curvilinear, serpentine-shaped, zigzag, or wavy) path and causes the tape segment to bend to follow the course / development of the path itself.

[0014] Preferably, the accumulation of curved tape is created by pushing or sliding the tape segment against one or more deflector or guide members placed on the edge-banding head, which cause respective changes in direction on the tape segment, and / or against a curved wall that causes the tape segment to curve in order to create, for example, a loop on it or to wrap the tape segment around itself.

[0015] Preferably, for compactness, the tape segment is loaded onto the edge-banding head, creating a winding with the tape segment (the accumulation of curved tape is a winding), in particular by winding the tape segment around or inside a circular member located on the edge-banding head.

[0016] To ensure repeatable and efficient formation of the accumulation, preferably one end of an external tape is blocked on the edge-banding head at a point of the edge-banding head, the point is moved relative to the rest of the edge-banding head to drag a segment of tape onto the edge-banding head and form the accumulation of curved tape, and the tape is cut determining the length of the tape segment loaded onto the edge-banding head as the length between said blocked end and an end created by the cut.

[0017] With the same advantage, preferably one end of an external tape is blocked on the edge-banding head at a point on the edge-banding head, the point is rotated along a circumference relative to the rest of the edge-banding head to drag a segment of tape onto the edge-banding head and form a circular winding of tape; the tape is cut determining the length of a circumference of tape loaded onto the edge-banding head as the length between said blocked end and an end created by the cut.

[0018] Preferably, the edge-banding head comprises an application zone or means for applying tape to the panel, and said blocked end or said end created by the cut is moved towards said area or means.

[0019] Preferably, in the application zone, the tape is coated with adhesive before application to the edge.

[0020] Preferably, in the application zone, or by means of the means for applying, the tape is cut after the application to the edge (to cut off excess tape relative to the length of the edge).

[0021] Preferably, the edge-banding head is installed in a processing workstation of a group of N processing workstations, N ≥ 2, arranged in a circular series around a rotatable member on which the panels to be edge-banded are mounted, during the rotation of the rotatable member, each panel is always kept vertical, and preferably with the same major surface always facing radially outwards from the rotatable member; the panel is stopped sequentially at the N workstations to be machined, the panel arrives at the workstation hosting the edge-banding head, and the edge-banding head applies the tape to one edge of the panel mounted on the rotatable member.

[0022] Preferably, the tape is deposited by moving the edge-banding head sequentially only vertically and / or horizontally, or sequentially vertically and then horizontally, or vice versa, to edge-band corresponding sides of the panel.

[0023] In particular, the tape is deposited along the perimeter edges of the panel on surfaces of the panel corresponding to its thickness.

[0024] More preferably, the tape is deposited by moving the edge-banding head along a trajectory that travels along all the perimeter edges of the panel, or along a trajectory that runs only along a subset of the perimeter edges of the panel. The remaining perimeter edges are covered with tape by the same edge-banding head when it runs along a different trajectory, complementary to the first trajectory with respect to the perimeter edges, or by two edge-banding heads that run along different trajectories that are complementary to each other with respect to the perimeter edges.

[0025] Another aspect of the invention relates to an edge-banding head, for edge-banding furniture panels with a segment of tape, capable of performing the method.

[0026] The edge-banding head shares all the variants described for the method, and comprises: means or a storage unit for maintaining the tape segment in the form of an accumulation of curved tape during the movement of the edge-banding head, and an application device for applying a length of tape to an edge of the panel by straightening tape taken from the accumulation, preferably until the accumulation is depleted.

[0027] Said means or storage unit may comprise a labyrinth, or a series of linear or curved guides, or a series of obstacles, configured to determine a plurality of changes of direction for the tape and force it to form an accumulation of curved tape, and more preferably also configured to keep the accumulation of curved tape stable and / or permanent during movements of the edge-banding head towards and along the edge to be covered with tape.

[0028] Said means or storage unit, in order to achieve the accumulation in a simple but efficient manner, more preferably comprise a circular member configured to wind the length of tape onto itself on a track, and a drive for rotating the circular member.

[0029] More preferably, in order to adapt the edge-banding head to various types of tape, the circular member is made up of two circular components placed side by side which are relatively movable along the axis of rotation of the circular member to vary the width of the track.

[0030] Preferably, the edge-banding head comprises a blocking member, e.g. mounted on the circular member, which is configured to block one end of the tape on the circular member (so that the circular member can pull the tape as it rotates).

[0031] To facilitate the application of the tape to the edge, the edge-banding head preferably comprises an application device for applying tape to the panel, and a movable arm for bringing one end of the tape coming and taken from the accumulation of curved tape towards the application device in order to feed the tape to the application device.

[0032] More preferably, the arm is movable between two positions: a first position in which the arm guides a portion of tape toward the circular member to form the accumulation of curved tape, and a second position in which it brings an end of the tape coming and taken from the accumulation closer to the application device.

[0033] For mechanical compactness, the movable arm is preferably a rotatable arm, more preferably having an axis of rotation coinciding with that of the circular member.

[0034] To facilitate the movement of the tape onboard the edge-banding head, the movable arm preferably comprises a blocking member for attaching one end of the tape to a point on the movable arm (e.g. a suction cup).

[0035] Preferably, the application device comprises: an adhesive dispenser for spreading adhesive onto tape coming from the accumulation of curved tape before the application to the edge, and / or means for cutting the tape after the application to the edge.

[0036] For the method, the edge-banding head, and the machine, the panel may be, for example, made of wood or plastic, and in particular for constructing furniture.

[0037] Said accumulation has the shape of, for example, a spiral, a helix, or a serpentine or a winding, having for example circular, polygonal, or mixed-line shape.

[0038] Further advantages will become clear from the following description, which refers to a preferred embodiment of an edge-banding head in which: Figure 1 shows a side view of the edge-banding head; Figures 2 and 3 show cross-sectional views according to plane II-II of Fig. 1 for two different operating configurations; Figures 4-7 show a side view of the edge-banding head in different operating configurations; Figures 8-9 show front views of a panel machining workstation incorporating the edge-banding head; Figure 10 shows a plan view of a CNC machine.

[0039] Equal numbers in the figures indicate identical or substantially identical parts. In order not to crowd the drawings, identical members are sometimes not numbered.

[0040] An edge-banding head MC comprises a frame 10 that supports a tape loading device 20 and a tape application device 70 (Fig. 1).

[0041] The tape loading device 20 comprises a rotatable member 22 rotatable about an axis X of rotation on two supports 24. The rotatable member 22 is formed of two flanged rings 26, each pivoted on its respective support 24. Each flanged ring 26 comprises a track 30 and a flange 28, and can be set into rotation by a drive 98.

[0042] As explained below, the rotatable member 22 serves to wind a length of tape onto the edge-banding head MC.

[0043] By means of a drive 96, the supports 24 are translatable independently parallel to the X axis (see arrow F1) to separate or bring closer the flanged rings 26, so that the relative distance between the two tracks 30 and therefore the effective width of the overall track between the flanges 28 can be varied. See, for example, the two different configurations shown in Figs. 2 and 3.

[0044] On one of the two flanged rings 26 there is a movable blocking member 42, e.g. a tooth or a dowel, which can be actuated to be pushed against the track 30.

[0045] An arm 30 is pivotally mounted about the X-axis, at the free end of which a pedestal 32 is mounted comprising a flat surface 34 approximately tangent to the track 30. A tape blocking member 44 (e.g. a suction cup) is installed in the flat surface 34.

[0046] The tape application device 70 comprises: a conveyor belt 72 which can be driven by known motor rollers 74; a shear 76 mounted above the conveyor belt 72 with the blade facing the conveyor belt 72, and an adhesive dispenser 78 directed towards the conveyor belt 72.

[0047] The edge-banding head MC is fed from, and cooperates with, a tape storage unit 96, which may be of a known type, preferably capable of dispensing a predetermined length of tape.

[0048] In the drawings, as an example, the storage unit 96 comprises: a tape dispensing plane 92, a shear 90 with a blade facing the plane 92, and leveling and / or feed rollers 86, 88.

[0049] The roller 88 is opposite and almost in contact with the plane 92, while the roller 86 is movable relative to the plane 92 so as to be able to align with the roller 88 and almost touch the flat surface 34 or to be able to move away from the flat surface 34.

[0050] The arm 30 is movable between two positions: a first position in which the flat surface 34 is coplanar with the outlet or the plane 92 of the storage unit 96 and tangent to the tracks 30, and a second position in which the flat surface 34 is coplanar with the plane of the conveyor belt 72. OPERATION

[0051] A sequence of operating steps for the edge-banding head MC is now described. [1] (Fig. 1): The arm 30 is in the first position, where the flat surface 34 and the plane 92 are coplanar. The rollers 86, 88 are aligned with the plane 92 and a segment of tape 94 slides between the plane 92 and the rollers 86, 88 towards the rotatable member 22. Optionally, the distance between the supports 24 is adjusted to adapt the width between the flanges 28 to that of the tape 94. [2] (Fig. 4): When the free end of the tape 94 has reached the tracks 30, the blocking member 42 is lowered to clamp such end against at least one track 30. Now the end of the tape 94 is integral with the rotatable member 22. Then the rotatable member 22 is set into rotation to wind a segment of tape of a predefined length onto the tracks 30 and thus load the edge-banding head MC with an accumulation of curved tape. Figs. 4-7 show the winding of tape 94 in transparency. [3] (Fig. 5): Once the winding is complete, the rotatable member 22 stops, the tape 94 is cut by the shears 90, and the cut end of the tape 94 is blocked onto the flat surface 34 by the blocking member 44. The roller 86 lifts off the flat surface 34. [4] (Fig. 6): The arm 30 rotates (arrow F2) to end up in the second position, where the flat surface 34 is now coplanar with the conveyor belt 72. The blocking members 44 and 42 are deactivated to release the tape segment 94 from the rotatable member 22, and the conveyor belt 72 is activated to advance the tape segment 94 toward the adhesive dispenser 78, unwinding it from the rotatable member 22. [5] (Fig. 7): As the tape segment 94 grazes the adhesive dispenser 78, the latter spreads adhesive onto the tape 94. The tape 94 passes past the adhesive dispenser 78 and protrudes from the conveyor belt 72. During the adhesive spreading, the edge-banding head MC is moved to deposit the tape 94 protruding from the conveyor belt 72 onto a panel edge. Once the tape 94 has been laid, the shear 76 is activated to cut off a possible excess of tape 94. [6] (Fig. 1): The arm 30 returns to its initial position, the roller 86 approaches the flat surface 34 to realign with the roller 88, and the cycle restarts for another accumulation of tape and a different panel edge.

[0052] In a preferred embodiment, the edge-banding head MC is installed on board an edge-banding workstation, which is a standalone unit or included in a larger CNC machine tool 500, see fig. 10, which comprises a central member 510 rotatable about a vertical axis, and N machining workstations 520, N ≥ 2, arranged in a circular series, preferably with a constant angular pitch, around the member 510; wherein the rotatable member 510 is capable of sequentially feeding a panel to each of the N workstations 520, and the edge-banding head MC is installed in at least one of the N workstations 520.

[0053] A preferred embodiment for the workstation 520 is shown in Figs. 8-9.

[0054] The workstation 520 comprises two parallel vertical columns 60 on which one or two horizontal bars 62 are mounted so as to be vertically translatable (arrow F3) by means of known drives. A carriage 64 is mounted on each horizontal bar 62 and is linearly translatable, by means of known drives, on the respective horizontal bar 62 (arrow F4).

[0055] An edge-banding head MC is mounted on the carriage 64, the former being capable of moving along two axes thanks to the coordinated movement of the horizontal bars 62 and the carriages 64.

[0056] The edge-banding head MC travels along one vertical side of the panel 200 (shown in dotted lines), depositing a strip of tape, spread with adhesive, over it; the strip will constitute the panel edge.

[0057] Once the tape has been applied, the edge-banding head MC cuts off the excess tape that protrudes beyond the length of the panel side.

[0058] To improve cycle time, preferably in the edge-banding workstation 300 there are two identical edge-banding heads MC that simultaneously work in the above manner on a respective vertical side of the panel 200.

[0059] In a different variant, the edge-banding head MC works in the same way on the horizontal sides of the panel 200. Here too, to improve cycle time, there are preferably two identical edge-banding heads MC working simultaneously on a respective horizontal side of the panel 200.

[0060] In one variant, the pedestal 32 or the edge-banding head MC comprises means for cutting the tape 94 after it has been wound onto the rotatable member 22 in order to separate it from the storage unit 96.

[0061] The drive 96, 98 may be, for example, an electric or pneumatic motor.

Claims

1. Method for covering a panel edge by applying a covering tape to the edge, with the steps of - loading a segment of tape onto an edge-banding head by installing an accumulation of curved tape on the edge-banding head; - moving the edge-banding head parallel to the edge and simultaneously applying the segment of tape to the edge by picking up tape from the accumulation.

2. Method according to claim 1, wherein an accumulation of already formed curved tape is loaded onto the edge-banding head.

3. Method according to claim 1, wherein the accumulation is formed on the edge-banding head while loading the tape onto the edge-banding head.

4. Method according to claim 3, wherein the accumulation of curved tape is created by directing the segment of tape into a curved guide located on the edge-banding head, wherein the guide defines a tortuous path and causes the segment of tape to bend to follow the course of the path itself.

5. Method according to claim 4, wherein the curved tape accumulation is created by pushing or sliding the tape segment against one or more deflecting or guiding members located on the edge-banding head that cause respective changes in direction on the tape segment.

6. Method according to claim 4, wherein the curved tape accumulation is created by pushing or sliding the tape segment against a curved wall that causes the tape segment to curve.

7. Method according to any one of claims 3 to 6, wherein one end of a tape external to the edge-banding head is blocked at a point of the edge-banding head, the point is moved relative to the remainder of the edge-banding head to drag a tape segment onto the edge-banding head and form the curved tape accumulation, and the tape is cut thereby determining the length of the tape segment loaded onto the edge-banding head as the length between said blocked end and an end created by the cut.

8. Method according to claim 6, wherein one end of a tape external to the edge-banding head is clamped at a point of the edge-banding head, the point is rotated along a circumference relative to the rest of the edge-banding head to drag a segment of tape onto the edge-banding head and form a circular winding of tape; the tape is cut thereby determining the length of a circumference of tape loaded onto the edge-banding head as the length between said clamped end and an end created by the cut.

9. Method according to claim 7 or 8, wherein the edge-banding head comprises a zone or means for applying tape to the panel, and said clamped end or said end created by the cut is moved toward said zone or means.

10. The method according to claim 9, wherein in said application zone, or by said application means, the tape is cut after application to the edge to cut off an excess of tape with respect to the length of the edge.

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