A panel edge machining unit

Abstract: A unit for machining edges of panels (1) envisages two operating units (6, 7) controlled by means (8) which adjust and drive the units themselves and which comprise a respective structure (9, 10) that moves in both directions along an axis (Z) which is inclined with respect to a panel (1) feed line (L) and along a plane which is parallel to a vertical plane (V). Each structure (9, 10) is pivoted at (U1; U2) so as to enable the structures (9, 10) to swing in both directions in such a way as to drive each unit (6, 7) along defined straight and arched paths and in such a way as to define on the panel (1) two or more working positions, in permanent contact with the panel, such that both the units (6, 7), cause a band (4) applied to the edge (1b) to copy the shape of the edge itself.

Description: The present invention relates to a unit for machining the edges of panels for edge banding machines and used in particular to machine the edges of panels made of wood or similar material to which a strip made preferably, but not only, of synthetic material has been applied. The panels made of solid wood or wood derived material such as chipboard or even of plastic are widely used in the manufacture of furniture and shelving and come in many different sizes and shapes, depending on market requirements and on what the panels will be used for. The production line for panels of this kind consists of machines, known as "transfer" machines, where the panel is fed along two or more successive units, hereinafter referred to as machining stations. These machines are normally used to perform a certain number of operations, which are always identical within a single batch, on large numbers of panels to be used for the manufacture of furniture. During the process, the large surfaces of the "unfinished" panel (especially if it is a chipboard panel) are covered by a veneer of decorative wood or laminate in order to give the panel an attractive surface finish. The veneering varies in colour and material according to the purpose of the panel. Once the panels have been covered, they are cut down to the required sizes and are transferred to an edge banding station where a strip or edge band is glued to the uncovered edge of each panel. To ensure that the edge of the panel is covered completely, the edge band is larger in area than the edge of the panel and is applied in such a way that it protrudes from the latter. In order to finish the panel, the protruding sections must be trimmed in order to reduce the edge band to the same size as the panel edge. This is done at a station following the edge band gluing station. This station consists of two or more substations, each designed to perform a specific operation. Thus, as the panel moves along a horizontal feed path, it comes to a first operating unit comprising at least one end trimming tool which cuts the edge band at the front and back ends of the panel so that the length of the edge band is the same length as the panel edge. Next, the panel reaches a second operating unit where a trimming tool trims the top and bottom excess parts of the edge band lengthways. After these two operations, if the panel has sharp-edged ends, it may be fed to yet another station where minor imperfections caused by the two previous operations are removed by panel finishing units. If the profile of one of the edges at a corner of the panel has one half radiused or with a straight angle, the panel will be machined at the edge banding station by suitably profiled tools designed to copy the front and back of the radiused end profile at the ends of the panel edge. Since these machines are large and expensive in their final assembly line configuration, the policy adopted by manufacturers is, where possible, to reduce the size of individual stations and to eliminate operating elements and accessories in such a way as to make the machine more economical, also according to the type of end product made. This size reduction can be achieved by creating multifunctional operating units, especially for the end trimming, lengthways trimming and profiling operations described above. For example, a configuration with four power-driven units has been known for some time. These are four electro-spindles with tool and edge profile copier with which, by guided driving close to the panel feed line, it is possible to perform these operations, even if the operating elements have to be changed between one operation and the next. For example, the operating elements (or at least the tools) must be changed when one passes from panels with a relatively thick veneer to panels with a thin veneer or no veneer at all, or if panels with straight or tapered edge are being machined. In another solution, designed and made by the Applicant (see patent application IT - BO97A000188, which discloses the preamble of claim 1), the size of the station was reduced by using only two operating units, independent of each other, and each consisting of a single power tool equipped with a corresponding panel edge copier. Each unit is connected to means for driving the tool in directions lying in a vertical plane in such a way that each unit is driven along two controlled axes (the X-axis and Z-axis on the machine) following predetermined paths such as to define two or more working positions on the panel, in permanent contact with the panel in such a way that the edge band copies the shape of the panel edge. Although this solution reduces the number of operating units used, it does not significantly reduce the working dimensions of the operating units (one above and one below) since each unit must run on a corresponding linear guide (along the lengthways X-axis) of the edge banding station which are relatively long and which cannot lie over each other. After innumerable studies, the Applicant has managed to create a panel edge machining unit whose dimensions are even smaller than those of the above mentioned solution thanks to the use of operating units structured in such a way as to enable the end trimming, lengthways trimming and profiling operations to be performed on the panel without changing any operating element and with extremely reduced movements for each unit, while maintaining high machining speeds and high quality standards of the end product. The technical characteristics of the invention, according to the above mentioned aims, are described in independent claim 1 and its advantages are apparent from the detailed description which follows with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention without restricting the scope of the inventive concept and in which: Figures 1, 2 and 3 are partial perspective views showing differently shaped panel ends with edge bands applied to them which have been machined with the edge machining unit made according to the present invention; Figure 4 is a schematic front view, with some parts cut away in order to better illustrate others, of a panel edge machining unit made according to the present invention; Figure 5 is an exploded perspective view, with some parts cut away in order to better illustrate others, of the panel edge machining unit illustrated in Figure 4; Figures 6a, 6b, 6c and 7a, 7b, 7c show some operating steps of one of the elements of the machining unit made according to the present invention, in schematic side views with some parts cut away in order to better illustrate others. With reference to the accompanying drawings, in particular Figures 1, 2 and 3, the edge machining unit disclosed is used in particular to machine prism-shaped panels 1 made of wood or plastic and with edges 1b of limited thickness S. The ends of the panels 1a have differently shaped edges, for example, sharp edges (see Figure 1) or radiused to varying degrees as far as a straight angle (two examples of such radiused edges are shown in Figures 2 and 3). The edge banding unit 2 disclosed forms part of machines having a horizontal table 3 along which the panel 1 is moved along a feed line, indicated by the arrow L, to two or more successive stations. At these stations, which are not illustrated since they are of the known type, a band 4 of material, preferably a synthetic material, lying in a vertical plane V (see Figure 3) perpendicular to the feed table 3, is glued to the edge 1b of the panel 1, the band projecting from the edge 1b itself (in Figures 1 to 3, the "unfinished" band 4 is drawn with a dashed line). The unit 2 disclosed basically comprises means 5 for machining the band 4 in such a way as to reduce the band to the size and shape of the edge 1b of the panel 1. The means 5 for machining the band 4 comprise two operating units 6 and 7, independent of each other and each consisting of a single power tool equipped with corresponding means for copying the edge 1b of the panel 1. The units 6 and 7 are not described or illustrated in detail since they fall within the scope of patent application No. BO97A000188 by the same Applicant. As clearly shown in Figures 4 and 5, each of the operating units 6 and 7 is connected to means 8 which control and drive it and which comprise a corresponding structure 9 and 10 that moves in both directions (see arrows F) along an axis Z which is inclined with respect to the panel 1 feed line L and along a plane which is parallel to the vertical plane V. Each of these structures 9 and 10 is pivoted, at U1 and U2 respectively, in such a way as to enable the structures 9 and 10 to swing in both directions (see arrows F1) in such a way as to drive each unit 6 and 7 along predetermined straight and arched paths and in such a way as to define on the panel 1 two or more working positions, in permanent contact with the panel, such that both the units 6 and 7, cause the band 4 to copy the shape of the edge 1b of the panel 1. In other words, each unit 6 and 7, thanks to the corresponding structure 9 and 10, can machine the panel 1 in such a way as to perform end trimming, lengthways trimming and profiling of the edge band 4. In particular, as described in more detail below, each unit 6 and 7 covers one half of the profile of the edge 1b of the panel 1 thanks to the straight and arched path followed by the structure. Looking more closely at the constructional details, one of the structures, the one labelled 9, is pivoted at U1, below the work table 3, and is connected to a fixed machine bed 11 to which the unit 2 is fitted in such a way that the operating unit 6 works below the table and at the front end of the panels 1 in relation to their feed direction along the feed line L. The other structure, the one labelled 10, is pivoted at U2 to a vertical column 12 connected to the bed 11, at a point U2 above the work table 3 in such a way that the operating unit 7 works above the table 3 and at the rear end of the panels 1 in relation to their feed direction along the feed line L. The second structure 10, since it is above the table 3, is equipped with means 13 for adjusting it in such a way as to vary the height of the related unit 7, towards or away from the table 3 (see arrows F2), according to the thickness S of the panel 1 to be machined. Looking in more detail, each of the structures 9 and 10, consists of a block 14, 15 which mounts the corresponding operating unit 6, 7 and to which there is connected a first piston 16, 17 whose stem 16', 17' is attached to a fixed surface 18, 19 of a beam 20, 21 extending at an angle to the work table 3. Each of the fixed beams 20, 21 has a guide 22, 23 in which the block 14, 15 runs in such a way that the action of the first piston 16, 17 raises or lowers the corresponding unit 6, 7 relative to the work table 3, in a straight path. Each of the beams 20, 21 is equipped, at an intermediate point, with a corresponding pin 24, 25 defining the above mentioned pivot point U1, U2: the first pin 24 is attached to the bed 11 by a mounting plate 30, while the second pin 25 is attached to the vertical column 12 by a shaped bracket 31. Thanks to this pivot point, the two units 6, 7 can swing in both directions so as to follow the profile of the edge 1b of the panel 1. The path followed is arched thanks to a corresponding second piston 26, 27 whose stem 26', 27' is attached to a free end of each beam 20, 21 by a corresponding fork 32, 33. The cylinder of each second piston 26, 27 is attached to the bed 11 and to the column 12, respectively. In particular, the cylinder of the second piston 27 acting on the second structure 10 is attached to an extension 34 of the bracket 31. The above mentioned means 13 for adjusting the second unit 7 in height (see Figure 5) consist of a carriage 28 connected to the vertical column 12, supporting the entire structure 10 and sliding on a guide 35 made on the vertical column 12. The slide 28 is acted upon by a drive unit 29 consisting of a lead nut and screw assembly 36 and 37 connected to a bevel gear pair 38 designed to transmit motion from adjustment means (not illustrated) to the drive unit 29 itself. The bevel gear wheels 38 and the adjustment means are housed near the bed 11: in this way, it is possible to adjust the starting height of the second unit 7 in accordance with the thickness S of the panel 1 to be machined. Obviously, the units 6 and 7, the pistons 16, 17, 26, 27 and the means 13 for adjusting the height of the second unit 7 are controlled by a drive unit 39 of the profiling machine (illustrated schematically as a block since it is of the known type). An edge banding unit made in this way can perform all edge banding operations extremely quickly and accurately. For example, Figures 6 and 7 show, in alphabetical sequence, the different stages in the machining cycle of the first unit 6, that is, the front, lower one. In these illustrations, the unfinished edge band 4 is drawn with a dashed line. As shown in Figures 6a to 6c, the unit 6 is located at the centreline of the panel 1 being fed until contact between the unit 6 and the panel 1 occurs (see Figure 6a), that is to say, until the copier and tool assembly reaches the panel 1. At this point, the first control piston 16 enables the unit 6 to move downwards (arrow F3, Figure 6b), gradually profiling the edge of the panel 1, which in this case is radiused at a straight angle (see Figure 6b). As the panel moves forward, the tool automatically follows the profile of the panel downward along F3 and until it reaches the body of the panel, where the unit 6 is held in a stable position so as to trim the lower part of the edge of the panel 1 as the latter continues moving forward (see Figure 6c). Preferably, the holding of the tool in this stable position is facilitated by the second piston 26. As the panel 1 continues moving forward, the unit 6 reaches the back end of the panel 1 (see Figure 7a). At this point, the second piston 26 comes into operation and causes the unit 6 to rotate about the pivot point U1 (see arrow F5, Figure 7b) so as to follow the rear edge 1b along the arched path in such a way as to copy the shape of the edge 1b of the panel 1 until it reaches the centreline (see Figures 7b and 7c, arrow F5). Similarly, the second unit 7 profiles and trims the front and rear of the upper part of the edge 1b of the panel 1. The motion of the unit 7 is substantially symmetrical to that followed by the unit 6 and in the opposite direction. A unit as described above therefore achieves the set aims with its simple, compact structure and thanks to the two inclined units which work one above the other in a reduced space. Moreover, the unit in no way affects the quality standard of the end products and the high operating speeds required of machines of this kind.

Claims: A unit for machining panel edges, especially for machining prism-shaped panels (1) made of wood or plastic, with edges (1b) of limited thickness (S), and differently shaped ends (1a), for example, with sharp edges or radiused to varying degrees as far as a straight angle; said unit (2) forming part of machines having a horizontal table (3) along which the panel (1) is moved along a feed line (L), to two or more successive stations where a band (4) of material, preferably a synthetic material, lying in a vertical plane (V) perpendicular to the feed table (3), is glued to the edge (1b) of the panel (1), the band projecting from the edge (1b) itself; said unit (2) comprising means (5) for machining the band (4) in such a way as to reduce the band to the size and shape of the edge (1b) of the panel (1); the means (5) for machining the band (4) comprising two operating units (6, 7), which are independent of each other and each consisting of a single power tool equipped with corresponding means for copying the edge (1b) of the panel (1); the unit being characterized in that each of the operating units (6, 7) is connected to means (8) which control and drive it and which comprise a corresponding structure (9, 10) that moves in both directions along an axis (Z) which is inclined with respect to the panel (1) feed line (L) and along a plane which is parallel to the vertical plane (V); each of the structures (9, 10) being pivoted, at (U1; U2) in such a way as to enable the corresponding structure (9, 10) to swing in both directions so as to drive each unit (6, 7) along predetermined straight and arched paths and in such a way as to define on the panel (1) two or more working positions, in permanent contact with the panel, such that both the units (6, 7) cause the band (4) to copy the shape of the edge (1b). The unit according to claim 1, characterized in that the first structure (9) is pivoted at (U1), below the work table (3), to a fixed bed (11) of the unit in such a way that the operating unit (6) works below the table and at the front end of the panels (1) in relation to the feed line (L); the second structure (10) being pivoted to a vertical column (12) connected to the bed (11) at a point (U2) above the work table (3); the second structure (10) being equipped with means (13) for adjusting it in such a way as to vary the height of the related unit (7), towards or away from the table (3), according to the thickness (S) of the panel (1) to be machined and in such a way that the unit (7) works above the table (3) and at the rear end of the panel in relation to the feed line (L). The unit according to claim 1, characterized in that each of the structures (9, 10), consists of a block (14, 15) which mounts the corresponding operating unit (6, 7) and to which there is connected a first piston (16, 17) whose stem (16', 17') is attached to a fixed surface (18, 19) of a beam (20, 21) extending at an angle to the work table (3); each fixed beam (20, 21) having a guide (22, 23) in which the block (14, 15) runs in such a way that the action of the first piston (16, 17) raises or lowers the corresponding unit (6, 7) relative to the work table (3), in a straight path. The unit according to claims 2 and 3, characterized in that the beams (20, 21) of the structures (9, 10) are equipped, at intermediate points along them, with corresponding pivot pins (24, 25) attached to the bed (11) and to the vertical column (12), respectively, and designed to enable each of the units (6, 7) to swing in both directions by means of respective second pistons (26, 27) attached by their stems (26', 27') to a free end of the beams (20, 21) and by their cylinders to the bed (11) and to the column (12), respectively. The unit according to claim 2, characterized in that the means (13) for adjusting the height of the second unit (7) consist of a carriage (28) slidably connected to the vertical column (12) and mounting the unit (7); the carriage (28) being acted upon by a drive unit (29) consisting of a lead nut and screw assembly (36, 37) connected to a pair of bevel gear wheels (38), one of which is motor driven in such a way as to enable the unit (7) to be raised or lowered relative to the work table (3) in accordance with the thickness (S) of the panel (1).

Inventors: CAVALLI GIUSEPPE, MAIOLI FABIO, ROSATI MASSIMO, CAVALLI, GIUSEPPE, MAIOLI, FABIO, ROSATI, MASSIMO
Applicants: SCM GROUP SPA, SCM GROUP S.P.A.
Application year: 1999
Main classification: B27D5
IPC codes: B27D5