Automatic banding machine for applying and finishing edges on wooden or similar panels

Abstract

The present invention relates to the field of processing structural slab-shaped elements made of wood or similar materials, and more specifically to a machine for finishing such elements. The invention relates in particular to an automatic edge banding machine for applying and finishing plastic edges on panels of wood or similar material, which can be used for the manufacture of doors, sashes, furniture, partition elements or other furniture components. More specifically, the invention relates to an edge banding machine for applying and finishing edges on panels with a curved profile.

Description

[0001] The present invention relates to the field of processing structural slab-shaped elements made of wood or similar materials, and more specifically to a machine for finishing such elements. The invention relates in particular to an automatic edge banding machine for applying and finishing plastic edges on panels of wood or similar material, which can be used for the manufacture of doors, sashes, furniture, partition elements or other furniture components. More specifically, the invention relates to an edge banding machine for applying and finishing edges on panels with a curved profile.

[0002] This type of panel is increasingly in demand in the furniture industry, which is now looking for more aesthetically elaborate and designer shapes.

[0003] However, machining curved shapes is particularly difficult and therefore an evolution of finishing machines is necessary to meet this requirement. For example, the use of manual or semi-manual finishing machines such as those currently in use is no longer advantageous and compatible with the complexity of the machining required. In fact, finishing machines are currently required to be able to work autonomously because manual operator intervention is an element of variability in precision standards and production speed.

[0004] Edge banding machines for curved panels are currently known, e.g. of the numerically controlled type with a vacuum worktable, i.e. exerting an attractive force on the panel by means of an air suction, or with a movable worktable and articulated arm.

[0005] To date, these known machines do not yet fully meet the requirements of efficiency, precision and processing speed demanded by the market.

[0006] The numerically controlled machines currently known traditionally include a multifunctional head, capable of milling, edging and trimming curved panels automatically. The various machining stages, particularly edge banding and finishing, are carried out in sequence, so the panel is moved several times around its entire perimeter in order to complete all the operations of the work cycle.

[0007] In general, a common feature of existing machines is the need to move the panel often, in different positions and several times around its perimeter. This still makes the working operation time-consuming, complex and can lead to positioning errors, which then affect the precision of the edge banding application.

[0008] In light of this state of the art, the aim of the present invention is to provide an automatic edge banding machine that is capable of edging a curved panel, that is reliable and that can process different panel formats.

[0009] A further aim is to provide an automatic edge banding machine that is fast and meets high precision standards.

[0010] This and other purposes are achieved by the automatic edge banding machine according to the present invention, the essential features of which are defined by claim 1 annexed hereto. Other important additional features are the subject matter of the dependent claims.

[0011] The characteristics and advantages of the edge banding machine according to the present invention will become clearer from the following description of embodiments thereof, given by way of a non-limiting example with reference to the appended drawings wherein: Figure 1 is a view of the machine as a whole; Figure 2 shows the machine in Figure 1 in a working step, with a panel to be machined mounted on the machine itself; Figure 3 is a view from above of Figure 2; Figure 4 is a more detailed view of the application station of the machine; Figure 5 is also a view of the application station, without a panel; Figure 6 shows first measuring means in isolation; Figure 7 shows a finishing station of the machine according to the invention; Figure 8 shows the machine in a working step from a further perspective; and Figures 9 and 10 show a schematic representation of two successive positions of the panel being machined; Figure 11 is a top view of a handling arm of the finishing station; and Figure 12 shows a top view of winch type pulling means of the articulated arm.

[0012] With reference to these figures, the machine comprises support means 1 adapted to support, move and keep in position the panel P to be edge banded during the machining steps. The support means 1 support the panel by arranging it in accordance with a working plane XY (Figure 2).

[0013] As can also be understood from the drawings, the panel P has a prevailing extension according to its face P0, which defines a main plane AA that is parallel to the plane XY when working and arranged on the support means 1. It then has an edge P1 that is perpendicular or substantially perpendicular to the face P0 and thus in the working step, perpendicular or substantially perpendicular to the working plane XY.

[0014] In the preferred solution illustrated in the figures, the support means 1 comprise a plate 10 that defines a resting surface 100 of the panel P. The resting surface 100 in turn defines the working surface XY.

[0015] The plate 10 provides means for the panel and in particular its face P0 to be firmly connected to it. Such firm connection means are, for example but not limited to, suction means that create a vacuum at the surface 100 of the plate capable of keeping the panel firmly attached. This type of solution will henceforth be referred to in the text as the vacuum plate 10.

[0016] The vacuum plate 10 is rotatably mounted around its own axis Z perpendicular to the plane XY on an articulated arm 11 The articulated arm 11 comprises a first segment or fixed segment 110 and a second segment or movable segment 111 articulated to each other. The two segments, as will become clear later on, are articulated to each other along an axis Z2 parallel to the axis Z, whereby the first segment 110 is rotatably connected to a machine frame around an axis of rotation Z1 parallel to the axis Z, whereby the articulated arm 11 moves the panel P on the working plane XY.

[0017] In more detail, the articulated arm 11 therefore extends between a fixed end 11a hinged to the machine frame and constrained to rotate about its own axis Z1 parallel to the axis of rotation Z of the vacuum plate and a free end 11b to which the vacuum plate 10 is rotatably connected.

[0018] The two segments 110, 111 of the articulated arm 11 are then hinged at an articulation point 11c interposed between the movable 11b and fixed 11a ends of the arm 11 where the articulation point 11c represents an additional degree of freedom to rotate about an axis Z2 parallel to the axis Z.

[0019] On the fixed end 11a of the articulated arm and the articulation 11c braking means operate, such as and not limited to a disc brake, to hold the arm firmly in a desired position.

[0020] The vacuum plate 10 can therefore move freely in any direction on the working plane XY.

[0021] The machine then comprises two work stations, one for applying the edge banding tape and one for finishing.

[0022] In the application station 2, the application of the edge banding tape N is carried out on the panel P and in particular on the edge P1.

[0023] This station comprises at least two motorised abutment rollers 20, 21 arranged so as to rotate each about its own axis of rotation Z3, Z4 parallel to the axis Z and at least one motorised pressure roller 22 (Figure 5) arranged so as to rotate about its own axis of rotation A1 perpendicular to the axis of rotation Z3, Z4 of the at least two motorised abutment rollers and arranged on a plane parallel to the working plane XY. The at least three rollers described above have the task of moving the panel P during application of the edge banding tape N. In detail, the at least one motorised pressure roller 22 moves the panel towards the at least two motorised abutment rollers 20, 21, bringing it into abutment on them.

[0024] The at least two motorised abutment rollers comprise at least a first application roller 20, which is the one that physically presses the tape against the edge P1, and a second application roller 21, which is spaced with respect to the first.

[0025] The edge banding tape N is fed to the application station 2 via a feeding unit 23. Next, an adhesive substance contained in a glue pot 24, such as but not limited to a thermoplastic adhesive, is applied to the edge banding tape. Once the adhesive has been applied, the edge banding tape N is adhered to the edge P1 of the panel through the pressure exerted by the first motorised roller 20. The motorised rollers 20, 21 contribute, together with the above-mentioned roller 22, to the advancement of the panel within the station by sliding it along its edge, i.e. by moving it in rotation about the axis Z and in translation on the plane XY, until the set length of the edge banding tape has been applied. For this purpose, the application station 2 of the edge banding tape also comprises first measuring means such as, but not limited to, a first encoder 25 measuring the length of the edge P1.

[0026] Going into more detail, with particular reference to Figures 5 and 6, the first encoder 25 is mounted on a rotating arm 250. The arm is rotatable with respect to the axis Z4 of the second roller 21. The encoder 25 comprises a touch wheel 251 kept in contact with the edge P1 of the panel P by means of the thrust force exerted on the rotating arm 250 by a torsion spring 252. By advancing the panel P, the touch wheel 251, and consequently the encoder, starts measuring the distance travelled and thus the perimeter of the panel P.

[0027] Second measuring means, such as but not limited to a second encoder 12, measure the rotation about its own axis Z of the plate 10 (Figure 1).

[0028] The machine also comprises a control centre with which the first and second measuring means communicate. When the second encoder 12 measures the complete rotation of the plate about the axis Z (i.e. 360°), the control unit sends an end-of-measurement signal to the first encoder 25; in fact - taking any point on the edge P1 of the panel as the start of measurement - the complete rotation of the plate 10 about the axis Z (i.e. 360°) will correspond to the measurement of the complete perimeter of the panel. This measurement is carried out at the pre-processing or presetting stage, i.e. before the edge banding and trimming operations.

[0029] Once the edge measurement P1 has been acquired then it is only possible to measure the length of the tape fed to the application station 2 - by means of a third encoder 26 - by sending a cutting signal to appropriate cutting means 27 when the length measured in the presetting step is reached. By way of non-limiting example, the cutting means comprise a shear placed next to and downstream of the edge feeding unit 23

[0030] In the machine, there is also a finishing station 3, shown in isolation in Figure 7. In finishing station 3, the upper and lower excesses of the tape N applied to the edge P1 are cut and trimmed. According to a particular aspect of the invention, with reference to Figures 7 to 11, the finishing station 3 is mounted on a rotatable arm 4 which is connected to the machine frame below the first tape application roller 20. The arm is thus rotatable with respect to the axis Z3. The rotatable arm 4 allows the trimming station 3 to follow the panel in its roto-translation motion on the plane XY (Figures 9 and 10).

[0031] Referring specifically to Figure 7, the trimming station 3 comprises two trimmers 30, 31 mounted one above the other and spaced on a post 320 that rises along its own axis Z5 parallel to the axis Z from a head 40 of the arm 4. In more detail, the post is rotatably connected to the head 40 around the axis Z5 in a tilting motion.

[0032] Each of the trimmers 30, 31 comprises one or more milling cutters. There are also at least two pairs of feelers 300, 310 each associated with a trimmer. In use, the panel is inserted into the space between the trimmers and they close on the panel, sliding along the post 320 in the axis Z5 until the two pairs of feelers make contact at the top and bottom with the two main flat faces thereof.

[0033] The station then includes a roller 32 controlling the position of the panel and an anti-rotation roller 33 arranged side by side on a tangent line A2 with the panel itself (Figure 9, Figure 10), a line lying on the plane XY.

[0034] The position control roller 32 is arranged coaxial and rotatable on the axis Z5. This roller makes tangential contact on the edge P1 of the panel P and verifies its positioning with respect to the trimmers.

[0035] Due to the degrees of freedom of the finishing station 3 with respect to the axis Z3 and axis Z5, the control roller 32 remains tangential to the panel throughout its machining movement on the plane XY.

[0036] Again, the anti-rotation roller 33 is mounted idle and rotates with respect to its own axis Z6 in a lateral position with respect to the control roller 32. In addition, the anti-rotation roller 33 is carried by the post in rotation about the axis Z5, in a tilting movement that allows the roller to follow the panel in tangency on line A2 (this movement is clearly shown in Figures 9 and 10).

[0037] At least the trimmers 30, 31 and then the control roller 32 and anti-rotation roller 33 are kept adhered to the panel by pneumatic actuation means that apply a torque on the axis of rotation Z5 in thrust against the panel. This torque is transmitted to the post via a drive system such as, but not limited to, a rack and pinion system and pneumatic actuator. The applied torque then pushes the post 320 against the panel and the anti-rotation roller 33 acts as a stop, preventing uncontrolled rotation of the head around Z5 beyond the tangency line between the edge and the roller itself.

[0038] For the rotation of the arm 4 around Z3, a power transmission system is used, by way of non-limiting example of the chain type with pneumatic rotary actuator.

[0039] From the above description, it is clear that in the machine according to the invention, the edging and finishing steps take place in a single movement of the panel, i.e. in a single machining session and simultaneously with each other. In fact, during a complete revolution of the panel around the axis Z, there will be times when in an edge segment P1a the edge banding tape will be applied, while in a previous edge segment P1b where the tape has already been applied the finishing station 3 will be acting. Therefore, at the end of one revolution around the axis Z of the vacuum plate 10 corresponding to one turn on itself of the panel, the panel will be perfectly completed, edged and finished. The ability of the application station 2 of the edge banding tape and the finishing station 3 to engage operationally on successive segments P1a, P1b of the edge at the same time is a not inconsiderable advantage in terms of processing speed and accuracy.

[0040] This is in fact not achieved by currently known machines where the application steps of the edge banding and finishing tape occur at separate and successive times with the need for an operator to reposition between steps. Among other things, the finishing step is often still carried out manually by the actual operator.

[0041] It should be noted that the ability of the finishing station to follow the edge of the panel in the plane XY due to the two degrees of freedom with respect to the axes Z3 and Z5 contributes precisely to achieving the result described above.

[0042] Furthermore, the automatic panel perimeter measurement system by means of a dual encoder 25, 12 allows the determination of the required edge length and avoids the corrections that characterise other measurement systems such as laser or manual measurement, thus speeding up machining operations and increasing the accuracy of the system.

[0043] The machine also comprises winch-type pulling means, which allow a constant tension to be applied to a cable of variable length (Figure 12). The pulling means are housed inside the machine frame and the cable is led out by a pivoting pulley 5 positioned immediately in front and centrally between the support rollers 20 and 21. The cable leaving the pulley is then attached to the end of the second segment of the articulated arm 110, below the vacuum plane 10 by means of a swivel eye. In this way the cable will always apply a constant force independent of the shape of the panel and position of the arm in the direction A3 from the vacuum plane 10 to the pivoting pulley 5, thus always having a force component in the direction A4 orthogonal to the tangent A5 to the support rollers 20,21.

[0044] When loading and unloading the panel, the force applied by the winch system would bring the arm against the machine, which is prevented by the braking means operating on the arm articulation points already described.

[0045] The winch-type pulling means therefore exert a pulling force on the panel against the support rollers 20, 21, which also opposes the force exerted by the trimmer 3, which in certain situations of position and shape of the panel can tend to make it detach from the support rollers. Such means also make it possible to increase the pressing force between the edge banding tape and the edge of the panel, resulting in a stronger bond.

[0046] The present invention has been described hereto with reference to preferred embodiments thereof. It is intended that other embodiments may exist which relate to the same inventive core, all falling within the scope of protection of the claims indicated below.

Claims

1. An automatic edge banding machine for applying and finishing an edge banding tape N to an edge P1 of a curved panel P, such as a panel of wood, plywood or similar materials or the like, comprising: - a support plate (10) which supports the panel P by arranging it in accordance with a working plane XY and which is rotatably mounted with respect to its own axis of rotation Z perpendicular to said working plane XY on a free end (11b) of an articulated arm (11); wherein said articulated arm (11) comprises a first segment (110) and a second segment (111) articulated around an axis Z2 parallel to said axis Z, said first segment (110) being rotatably connected to a frame of said machine around an axis of rotation Z1 parallel to said axis Z, said free end (11b) being an end of said second segment (111), whereby said articulated arm (11) moves said panel P on said working plane XY; - an application station (2) of the edging tape N to said edge P; - a finishing station (3) of the edging tape N applied on the edge P; wherein said panel P is carried by said articulated arm (11) operatively in engagement with said application station (2) and said finishing station (3) at the same time, said application station (2) and said finishing station (3) simultaneously working on different segments of the edge of said panel during a complete revolution of said plate (10) and thus of said panel P about said axis Z.

2. The machine according to claim 1 wherein said finishing station (3) is mounted on an arm (4) rotatably connected to a machine frame according to an axis Z3 parallel to the axis Z.

3. The machine according to claim 2 wherein said finishing station 3 comprises a post (320) defining a proper axis Z5 parallel to said axis Z3 connected to a head (40) of said arm (4) rotatably about said axis Z5, wherein said post mounts trimming means (30, 31).

4. The machine according to claim 3 wherein said finishing station (3) comprises a control roller (32) coaxial and rotatable with respect to the axis Z5, wherein during movement in the plane XY of the panel said control roller (32) is in tangency with said edge (P1).

5. The machine according to claim 4 wherein said finishing station (3) comprises an anti-rotation roller (33) mounted in an idle mode and rotatable with respect to its own axis Z6 in a lateral position with respect to the control roller (32) on a tangency line A2 to said panel and acting as a stop on said edge P1 of said panel P, said anti-rotation roller (33) being carried by the upright in rotation about said axis Z5 to follow the panel in tangency along the whole movement thereof in the plane XY and about the axis Z.

6. The machine according to claim 4 or 5 wherein at least said trimmers (30, 31) and said control roller (32) and said anti-rotation roller (33) are kept adhering to the panel by means of actuation means that apply a torque on the axis of rotation Z5.

7. The machine according to any one of claims 4 to 6 wherein said trimming means comprise at least two milling cutters arranged spaced apart on said post and sliding in reciprocal approach and / or departure to close on said panel arranged between them.

8. The machine according to claim 7 wherein said control roller (32) is arranged in an intermediate position between said at least two milling cutters.

9. The machine according to any one of the preceding claims wherein said application station (2) of the tape N on said edge comprises at least two motorised rollers (20, 21) arranged to rotate each about its own axis of rotation Z3, Z4 parallel to said axis Z, wherein a first applicator roller (20) arranged to exert pressure on said tape against said edge of said panel, said first roller (20) being rotatable about its own fixed axis Z3 which is also the axis of rotation of said articulated arm (4).

10. The machine according to claim 9 wherein said application station (2) comprises first measuring means (25) which measure the length of edging tape N applied to the edge P1 of the panel.

11. The machine according to claim 10 wherein second measuring means (12) are associated with said rotatable plate (10) and measure its rotation about its own axis Z.

12. The machine according to claim 11 comprising a control unit programmed to interrupt the measurement of the first measuring means (25) when said second measuring means (12) detect a complete revolution around the axis Z of the plate.

13. The machine according to any one of claims 10 to 12 wherein said first measuring means comprise an encoder (25) mounted on an arm (250) rotatable with respect to the axis (Z4) of a second roller (21), wherein said encoder (25) comprises a touch wheel (251) kept in contact with the edge P1 of the panel P by means of the thrust force exerted on said rotating arm (250) by a torsion spring (252).

14. The machine according to any one of claims 9 to 13 further comprising a third encoder (26) adapted to send a cutting signal to cutting means (27) of said tape when the measured length of said edge is reached by said first and second encoders.

15. The machine according to any one of claims 9 to 14 further comprising winch-type pulling means housed within the machine frame with a cable associated with a pivoting pulley (5) wherein said cable exiting the pulley is connected to the articulated arm (1) below the plane (10) the cable applying a constant force independent of the shape of the panel and position of the arm in a direction A3 from the plane (10) to said pivoting pulley (5).

16. The machine according to claim 15 wherein said pulley (5) is placed in front of said tape application station (2) in a central position with respect to said two motorised rollers (20, 21).

17. The machine according to any one of the preceding claims, wherein said articulated arm (11) comprises a fixed end (11a) of said first segment (110) hinged to said frame about said axis Z1, said articulated arm further comprising said free end (11b) of said second segment (111) to which said vacuum plate (10) is rotatably connected, wherein said two segments (110, 111) are hinged at an articulation point (11c) interposed between said free end (11b) and fixed end (11a) of the articulated arm (11).

18. The machine according to claim 17 wherein on said fixed end (11a) and on said articulation (11 c) operate braking means to hold the arm stably in a desired position.

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