Method and apparatus for surfacing a board-like object

Abstract: The present invention is related to a method of surfacing at least one wide side of a board-like substrate, in which method at least one wide side of the substrate board and at least one sheet or web of the surfacing material are placed opposing each other. In the method, the surfacing material (1) and the board-like object (2) of the substrate material are transferred into a positioning station so that the at least one aligned edge of the surfacing material (1) and the board-like substrate (2), respectively, are made to desiredly overlap or underlap the respective edge of the opposed element surface, or alternatively, that at least one of said edges is placed essentially aligned with other respective edge of the opposed element surface, irrespective of the initial position or alignment of the surfacing material (1) and/or the board-like substrate (2) to be transferred into the positioning station.

Description: The present invention relates to a method according to the preamble of claim 1. The invention further concerns an apparatus according to claim 12. In the art of manufacturing surfaced boards such as particle boards laminated with a variety of different surfacing materials such as a decorative melamine layer, the sheet of surface lamination has usually been made larger than the board to be surfaced. The need for this practice has chiefly been caused by the inaccurate positioning systems used in lamination. Conventional laminating lines have not been able to align the core board and surface sheet stacks in constant positions in a repetitive manner. Consequently, the positioning of the surface sheets with respect to the boards has been hampered by alignment errors. Hence, complicated positioning systems have been employed to locate the surface sheet accurately with regard to the substrate board. Moreover, it has been necessary to trim away the excess surface sheet overlapping the edges of the substrate board. This operation has needed an extra work step. As a result, the implementation of conventional lamination methods has involved the use of complicated apparatuses. A further handicap has been the material losses due to the trimmed-off edges. WO-A-86/01459 (see in particular figures 1 and 2 in combination with page 5, line 18ff.) is directed to a method of surfacing at least one wide side of a board like substrate 11 by a sheet of surfacing material (cover 13), the substrate and material being transferred to a positioning station 10, 21, 20 in such a manner that substrate and surfacing material will be positioned edge to edge. The edge alignment is achieved by the provision of a positioning station comprising a registering roller 21 cooperating with a registering plate 21 indirectly mounted to the substrate 11 to be surfaced, as best depicted in figure 1 of this publication. It is an object of the present invention to achieve a method of surfacing a board-like object by a surfacing material of sheet or web format in a manner capable of overcoming the drawbacks of prior-art methods. The method and apparatus according to the invention are characterized by what is stated in the appended claims. The method according to the present invention offers a number of significant benefits. For instance, the method according to the invention makes it possible to locate the surfacing material and the substrate board accurately into desired positions irrespective of the initial position or alignment of the surfacing material and/or the board-like substrate. Thence, the precise positioning of the surfacing material with respect to substrate such as a board avoids trimming waste of the surfacing material. The surfacing process will become simpler and faster. Also the apparatus required to implement the method will be less complicated. According to an embodiment of the invention, no complicated control systems are required. By virtue of using an elastic gripper means, the surfacing material and the substrate board can be located accurately against a backgage without any risk of damage to the surfacing material or the substrate board. In the following, the invention will be examined in with reference to the attached drawings in which Figure 1 shows schematically a board to be surfaced and the surfacing material sheets to be bonded thereto; Figure 2 shows a detail of a backgage assembly; Figure 3 shows the backgage assembly as seen from the direction of arrow III in Fig. 2; Figure 4 shows schematically an apparatus according to the invention; Figure 5 shows schematically the transfer of the surfacing material onto the substrate board; and Figure 6 shows the transfer of the substrate board onto the positioning platform. The method according to the invention for surfacing at least one wide side of a board-like object comprises positioning at least one wide side of the board with at least one sheet or web of the surfacing material opposing each other. According to the method, the surfacing material 1 and the board-like object 2 of the substrate material are transferred into a positioning station so that the at least one aligned edge of the surfacing material 1 and the board-like substrate 2, respectively, are made to desiredly overlap or underlap the respective edge of the other element, or alternatively, that at least one of said edges is placed essentially aligned with other respective edge of the other element, irrespective of the initial position or alignment of the surfacing material 1 and/or the board-like substrate 2 to be transferred into the positioning station. In an embodiment of the invention, at least two edges of the surfacing material 1 and the board-like substrate 2 are aligned to a desired overlap with the respective edge of the other element. Advantageously, said two edges are those meeting at a corner of the element. In another embodiment, at least two respective edges of the surfacing material 1 and the board-like substrate 2 are aligned with each other without an essential overlap or underlap of opposed element surfaces. Herein, the goal is to achieve an essential alignment of at least two respective edges of the opposed surfaces of the surfacing material 1 and the board-like substrate 2. The positioning of the board-like substrate and the surfacing material sheet is performed most appropriately with the help of a backgage 3. The backgage may be made fixed, or alternatively, movable to a desired position, whereby accurate location of the surfacing material 1 and the board-like substrate 2 is possible during the mutual positioning of these elements. In the method, the board-like substrate 2 and the surfacing material sheet or web 1 are positioned accurately above one another so that: either a substrate board 2 or a surfacing material sheet 1 is transferred into a position abutting a backgage 3, the substrate board 2 or respectively the surfacing material sheet 1 is lowered onto a platform 4 keeping it abutting the backgage 3, above the lowered element is brought a second element which may be respectively either a surfacing material sheet 1 or a substrate board 2, whereby it is positioned to abut the backgage 3, and the surfacing material sheet 1 or the substrate board 2, respectively, is lowered in abutting contact with the backgage 3 onto the sheet or board, respectively, resting on the platform 4. As mentioned above, the backgage 3 can be driven into a desired location prior to the positioning of the surfacing material sheet and/or the board-like substrate element. The surfacing material sheet or web 1 and/or the substrate board 2 are transferred onto the platform 4 by means of a positioning assembly 5 comprising at least one gripper means 6, 7, which is arranged to be elastic in at least one direction. The surfacing material sheet 1 and/or the board 2 are grabbed by the gripper means 6, 7 principally by the top surface of the element. Advantageously, the gripper means 6, 7 comprise at least one suction cup or the like gripper device. Advantageously, a greater number of suction cups 6, 7 is provided. Advantageously, the backgage 3 comprises two surfaces 8, 9 aligned orthogonally to each other. The set of gripper means 6, 7 is arranged to be elastic in at least one sideways direction perpendicular to the surface of the backgage 8, 9. According to the method, onto the platform is initially transferred a first surfacing material sheet 1, onto which is then transferred a board 2, whereafter a second surfacing material sheet 1 is lowered on top of board. The apparatus for accurate superimposed positioning of the board-like object 2 and the surfacing material sheet 1 comprises a positioning assembly 5 for transferring the surfacing material. sheet and/or the substrate board onto the platform 4. The positioning assembly includes at least one gripper means 6, 7 incorporating at least one elastic member 10, 11. The surfacing material sheet 1 and/or the substrate board 2 are moved by means of the positioning assembly 5 to abut at least one surface 8, 9 of the backgage. The elastic member 10 of the surface material gripper means 6 can be a spring or similar element. The elastic members 11 adapted to the gripper means 7 of the sheet 2 include telescoping slide members. The gripper means includes at least one suction cup or the like gripper device. The gripper means 6, 7 are advantageously connected via the elastic members 10, 11 to the positioning assembly 5. The positioning assembly 5 comprises the gripper means 6, 7 suitable for grabbing both the surfacing material sheet and the substrate board. Typically, the sheet gripper members comprise small-diameter suction cups 6 mounted on a support structure 12 such as a planar strip. In the context of the present invention, the term suction cup refers to a member having an essentially self-sealing rim so that a vacuum can be applied on the area enclosed by the rim. The strip 12 has advantageously an L-shaped form in a top view (refer to Fig. 5). With the help of the gripper means 6, the surfacing material sheet can be grabbed by its top surface, at least essentially close to the sheet corner to be abutting the inside corner of the backgage so that the edges of the sheet will be securely brought into contact with the backgage 3 when the sheet is being lowered by means of the gripper means. Typically, the gripper means 7 for grabbing the substrate board 2 comprise suction cups of larger diameter than the suction cups grabbing the surfacing material sheet. The backgage of the apparatus has two backing surfaces 8, 9 meeting at an angle á which advantageously is essentially equal to 90E. The same backing surface(s) is/are used in the positioning of both the sheet 1 and the board 2. According to a preferred embodiment of the.invention, the backgage is made essentially stationary. According to another embodiment, the backgage is made movable. The invention is suitable for use on the production lines of, e.g., laminated board products in which the surfacing material is in the form of a sheet or a web. After the accurate positioning operation, the sheet-board combination can be transferred from the platform to, e.g., a laminating press or similar post-processing apparatus. To those versed in the art it is obvious that the invention is not limited by the exemplifying embodiments described above, but rather, can be varied within the scope of the appended claims.

Claims: A method of surfacing at least one wide side of a board-like substrate, in which method at least one side of the substrate board and at least one sheet or web of a surfacing material are placed opposing each other, wherein the surfacing material (1) and the board-like object (2) of the substrate material are transferred into a positioning station so that the at least one aligned edge of the surfacing material (1) and the board-like substrate (2), respectively, are made to desiredly overlap or underlap the respective edge of the other element, or alternatively, that at least one of said edges is placed essentially aligned with other respective edge of the other element, irrespective of the initial position or alignment of the surfacing material (1) and/or the board-like substrate (2) to be transferred into the positioning station, characterized in that : either a substrate board (2) or a surfacing material sheet (1) is transferred into a position abutting a backgage (3), the substrate board (2) or respectively the surfacing material sheet (1) is lowered onto a platform (4) keeping it abutting the backgage (3), above the lowered element is brought a second element which may be respectively either a surfacing material sheet (1) or a substrate board (2), whereby said second element is positioned to abut the backgage.(3), and the surfacing material sheet (1) or the substrate board (2), respectively, is lowered in abutting contact with the backgage (3) onto the sheet or board, respectively, resting on the platform (4). A method as defined in claim 1, characterized in that at least two edges of the surfacing material (1) and the board-like substrate (2) are aligned to a desired overlap with the respective edge of the other element. A method as defined in claim 1, characterized in that at least two edges of the surfacing material (1) and the board-like substrate (2) are aligned without any essential overlap or underlap with the respective edge of the other element. A method as defined in claim 1, characterized in that at least two edges of the surfacing material (1) and the board-like substrate (2) are aligned essentially accurately with the respective edge of the other element. A method as defined in any of claims 1 - 4, characterized in that said backgage (3) is actuated into a desired position prior to the positioning of the surfacing material sheet and/or the board-like substrate. A method as defined in any of claims 1 - 5, characterized in that the surfacing material (1) and/or the substrate board (2) are transferred onto the platform by means of a positioning assembly (5) comprising at least one gripper means (6, 7), which is arranged to be elastic in at least one direction. A method as defined in any of claims 1 - 6, characterized in that the surfacing material (1) and/or the board (2) are grabbed by the gripper means (6, 7) principally by the top surface of the element. A method as defined in any of claims 1 - 7, characterized in that said backgage (3) comprises two surfaces (8, 9) aligned orthogonally to each other. A method as defined in any of claims 1 - 8, characterized in that said set of gripper means (6, 7) is arranged to be elastic in at least one sideways direction perpendicular to the surface of the backgage (8, 9). A method as defined in any of claims 1 - 9, characterized in that onto the platform (4) is initially transferred a first surfacing material sheet (1), onto which is then transferred a board (2), whereafter a second surfacing material sheet (1) is lowered on top of board. A method as defined in any of claims 1 - 10, characterized in that the gripper means (6, 7) comprise at least one suction cup or the like gripper device. An apparatus for accurate superimposed positioning of a board-like element (2) and a surfacing material sheet or web (1), said apparatus comprising a positioning assembly (5) for transferring the surfacing material sheet and/or the substrate board onto a platform, characterized in that the positioning assembly (5) includes at least one gripper means (6, 7) incorporating at least one elastic member (10, 11) and that the surfacing material sheet (1) and/or the substrate board (2) are moved by means of the positioning assembly (5) to abut at least one surface (8, 9) of a backgage. An apparatus as defined in claim 12, characterized in that said elastic member (10) is a spring or similar element. An apparatus as defined in claim 12 or 13, characterized in that said gripper means (6, 7) include at least one suction cup or the like gripper device. An apparatus as defined in any of claims 12 - 14, characterized in that said positioning assembly (5) comprises the gripper means (10, 11) suitable for grabbing both the surfacing material sheet (1) and the substrate board (2), respectively. An apparatus as defined in any of claims 12 - 15, characterized in that said gripper means (6) for grabbing the surfacing material sheet (1) comprise small-diameter suction cups. An apparatus as defined in any of claims 12 - 16, characterized in that said gripper means (7) for grabbing the substrate board comprise larger-diameter suction cups. An apparatus as defined in any of claims 12 - 17, characterized in that said backgage (3) is arranged to be movable. An apparatus as defined in any of claims 12 - 18, characterized in that the number of backing surfaces (8, 9) in said backgage is two, said backing surfaces being arranged at an angle (á) with regard to each other, said angle advantageously being essentially equal to 90E. An apparatus as defined in any of claims 12 - 19, characterized in that said elastic members (11) adapted to said gripper means (7) include telescoping slide members.

Inventors: SAUKKONEN SEPPO, SAUKKONEN, SEPPO
Applicants: METSO PANELBOARD OY
Application year: 1998
Main classification: B27N7
IPC codes: B32B37, B27N7, B32B7, B32B21, B27N3