WO2015118159A1

WO2015118159A1 - Method and apparatus for cooling boards, and a cooling turner

Info

Publication number: WO2015118159A1
Application number: PCT/EP2015/052674
Authority: WO
Inventors: Erno Tulonen; Janne NISKANEN; Markku KIRMANEN; Antti Korhonen
Original assignee: Dieffenbacher GmbH Maschinen- und Anlagenbau
Priority date: 2014-02-10
Filing date: 2015-02-10
Publication date: 2015-08-13
Also published as: DE112015000724T5; FI125432B; FI20145126A; CN206465230U

Abstract

Method for cooling boards (4) or board stacks in a cooling apparatus (26), which comprises a cooling turner (1), in which are prong rows (28) formed by support prongs (2), between which prong rows a board (4) or board stack to be cooled can be fitted and which prong rows are arranged to rotate around a common axis of rotation (29), and a conveyor (7) for bringing the board or board stack to the cooling turner (1), which conveyor (7) is arranged on the side of the cooling turner and above the prong row (28), and in which method individual boards (4) or board stacks are brought to the conveyor (7) for feeding into the cooling turner (1). At least one support prong (2) of at least one prong row (28) is provided with a support structure (3), with which a board (4) or board stack is supported during the turning for minimizing the bendings of the board (4) or board stack.

Description

METHOD AND APPARATUS FOR COOLING BOARDS, AND A COOLING TURNER

The invention relates to a method as defined in the preamble of claim 1 for cooling boards or board stacks in a cooling apparatus. The invention also relates to an apparatus as defined in the preamble of claim 6 for cooling boards and to a cooling turner as defined in the preamble of claim 16.

Wood-based boards, such as chipboards, MDF (Medium-Density Fibreboard) boards or OSB (Oriented Strand Board) boards, are manufactured by hot-pressing wood fibers and binder agent into an integral board with a hot press, after which the boards are sawn to the desired lengths. After this the boards are transported, singly or in stacks of two or more boards, to a cooling turner, in which the boards are cooled before stacking. If necessary, the edges of the boards can also be trimmed before cooling.

The cooling turner comprises a rotating cooling carousel, which typically comprises a cylindrical envelope, to which support prongs are fixed at one of their ends in the radial direction of the cooling carousel. The support prongs are arranged into prong rows in such a way that the support prongs of each prong row are on the same plane in the direction of the axis of rotation of the cooling carousel. On the side of the cooling turner is a conveyor, between the conveyor elements of which are gaps, through which the support prongs can travel. The board or board stack to be cooled is positioned into a standard location on the conveyor. After this the cooling carousel of the cooling turner is rotated, in which case the turning prongs of the prong row under the conveyor lift the board up from the conveyor. The board or board stack is turned 180 degrees between the prongs of two adjacent prong rows and lowered onto a conveyor on the second side of the cooling turner. After this the board or board stack is transferred to a second cooling turner or transported for stacking.

In the cooling turner the distance between the adjacent turning prongs of a prong row is rather large, typically 400-900 mm. The lengths of the boards to be cooled can vary steplessly. Since the second end of the board or board stack is positioned in a standard position at the end of the conveyor on the side of the cooling turner, a situation might arise in which the second end of the board or board stack comes between the adjacent turning prongs and is therefore unsupported. The length of the unsupported part can at its greatest be the amount of the distance between prongs, in which case the end of the stack or board stack might bend. Bending, in turn, causes inter alia displacement of the board or board stack between the prongs of the cooling turner and on the conveyors downstream of the cooling turner. The bending can be extensive, particularly with thin boards.

The bending problem can be reduced by situating the turning prongs more densely, but this considerably increases the manufacturing costs of the cooling turner.

The purpose of this invention is to achieve an improved method for cooling boards, an apparatus for cooling boards, and a cooling turner.

The aims of the invention can be achieved with a method according to claim 1, with an apparatus according to claim 6, and with a cooling turner according to claim 16.

The apparatus according to the invention comprises a cooling turner, in which are prong rows formed by support prongs, between which prong rows a board or board stack to be cooled can be fitted and which prong rows are adapted to rotate around a common axis of rotation, and also a conveyor for bringing the board or board stack to the cooling turner, which conveyor is arranged on the side of the cooling turner and above the prong row. The apparatus comprises a positioning device for transferring the board or board stack to the desired position on the conveyor. At least one support prong of at least one prong row is provided with a support structure for supporting the board or board stack during the turning.

According to one embodiment of the invention the support prong that is at the end of at least one prong row and/or the support prong beside the support prong that is at the end of a prong row is provided with a support structure for supporting the board or board stack beside the ends of the prong row and/or between the support prongs.

According to one embodiment of the invention the positioning apparatus is arranged to transfer a board or board stack according to its length to a determined position on the conveyor.

According to one embodiment of the invention the positioning device is arranged to transfer a board or board stack into a position in which one end of the board or board stack is at the point of a support prong provided with a support structure of the prong row that is under the conveyor, or at the point of the support structure of said support prong, or beside the support structure to the amount of a predetermined overshoot, and the second end of the board or board stack is beside one support prong of the prong row to the amount of a predetermined overshoot or at the point of the support prong.

According to one embodiment of the invention the length of the support structure is smaller than the distance between the adjacent support prongs of a prong row, typically 0.4-0.6 times the distance between the adjacent support prongs of a prong row.

According to one embodiment of the invention the apparatus comprises a control system, which is arranged to determine on the basis of length the position for the board or board stack on the conveyor and to control the positioning device in such a way that the board or board stack is transferred to the determined position.

According to one embodiment of the invention the apparatus comprises a measuring device for measuring the length of the board or board stack coming to the cooling turner, and the control system is arranged to determine on the basis of the measuring data of the measuring device the position for the board or board stack.

According to one embodiment of the invention the positioning device is disposed in the proximity of the end of the prong row on the support structure side.

According to one embodiment of the invention the positioning device is arranged to move in the direction of the axis of rotation of the prong rows.

According to one embodiment of the invention the positioning device and the support structure are arranged in the proximity of the start end or in the proximity of the finish end of a prong row.

In the cooling turner according to the invention are prong rows formed by support prongs, between which prong rows a board or board stack to be cooled can be fitted and which prong rows are adapted to rotate around a common axis of rotation. In addition, at least one support prong of at least one prong row is provided with a support structure for supporting the board or board stack during the turning.

In the method according to the invention individual boards or board stacks are brought to the conveyor for feeding into the cooling turner. At least one support prong of at least one prong row is provided with a support structure, with which a board or board stack is supported during the turning for minimizing the bendings of the board or board stack.

According to one embodiment of the method according to the invention a board or board stack is transferred with the positioning device to the determined position on the conveyor on the basis of the length of the board or board stack, in which position one end of the board or board stack is at the point of a support prong provided with a support structure of the prong row that is under the conveyor, or at the point of the support structure of said support prong, or beside the support structure to the amount of a predetermined overshoot, and the second end of the board or board stack is beside one support prong of the prong row to the amount of a predetermined overshoot or at the point of the support prong.

According to one embodiment of the method according to the invention the support prong that is at the end of a prong row and/or the support prong beside the support prong that is at the end of a prong row is provided with a support structure for supporting the board or board stack beside the ends of the prong row and/or between the support prongs.

According to one embodiment of the method according to the invention the magnitude of the overshoot is determined on the basis of the properties, such as the thickness, rigidity and/or material, of the board or of the boards of the board stack.

According to one embodiment of the method according to the invention the positioning device is moved in the direction of the axis of rotation of the prong rows for transferring a board or board stack to the determined position.

By means of the invention significant advantages are achieved. Bending of the boards to be cooled decreases because the length of the unsupported part of the boards, i.e. the magnitude of the overshoot, can be optimized to be such that detrimental bending does not occur. This, in turn, facilitates the handling of the boards in the handling phases subsequent to the cooling turner and improves the quality of the boards because permanent deformations do not form in the boards. In addition, the apparatus according to the invention can be implemented easily and inexpensively. In addition, existing cooling turners can easily be modernized into apparatuses according to the invention.

In the following, the invention will be described in more detail by the aid of an embodiment with reference to the attached drawings, wherein
Fig. 1 presents one apparatus according to the invention as viewed from above,
Fig. 2 presents the apparatus of Fig. 1 as viewed from the side,
Fig. 3 presents the apparatus of Fig. 1 as viewed from the end of the cooling turner, and
Fig. 4 presents positioning device of the apparatus of Fig. 1 and the first support prong of the cooling turner, and
Fig. 5 presents the positioning device of Fig. 4 as viewed from the side.

The drawings present an apparatus 26 for turning and/or for cooling boards. The apparatus 26 is a part of a manufacturing line, with which wood-based boards 4, such as chipboards, MDF (Medium-Density Fibreboard) boards or OSB (Oriented Strand Board) boards are manufactured. Wood-based boards are manufactured by hot-pressing wood fibers and binder agent into an integral board with a hot press, after which the boards 4 are sawn to the desired lengths. Typically the boards 4 are sawn to a length of 3000-5600 mm. After this the boards 4 are transported with a conveyor to the cooling turner 1, with which the boards 4 are turned 180 degrees for cooling them. Before the cooling turner 1, the boards can be prestacked into board stacks comprising a number of boards 4. In this case the boards 4 in each board stack are of the same length. A manufacturing line can comprise two or more cooling turners 1 fitted consecutively, between which a conveyor is fitted. If necessary, the edges of the boards 4 can be trimmed before cooling. The cooled boards 4 are transported for stacking.

A cooling turner 1 comprises a cooling carousel 27 rotating around an axis of rotation 29, which cooling carousel typically comprises a cylindrical envelope. Support prongs 2, e.g. structural hollow sections, are fixed at one of their ends to the cooling carousel 27 in the radial direction of the cooling carousel 27. The support prongs 2 are arranged into prong rows 28 in such a way that the support prongs 2 of each prong row 28 are on the same plane. The support prongs 2 of each prong row 28 are on the same plane in the direction of the axis of rotation 29. A board 4 or board stack to be cooled is between two adjacent prong rows 28 during the turning motion of the cooling turner 1. Typically there are 10-20 support prongs 2 in one prong row 28. The distance d between adjacent support prongs in a prong row 28 is typically 400-900 mm. The distance between adjacent support prongs 2 of the prong rows 28 is typically constant. The support prongs 2 are arranged with the same distribution into different prong rows 28. Typically a cooling turner 1 has 40-60 prong rows 28. The prong rows 28 are arranged evenly distributed on the rim of the cooling carousel 27 (Fig. 3 presents only some of the prong rows of the cooling turner). The cooling carousel 27 of the cooling turner is rotated by means of drive machinery, e.g. a reduction gear and a squirrel-cage motor controlled with a frequency converter.

The apparatus 26 comprises a conveyor 7, e.g. a roller conveyor, for bringing the board 4 or board stack to be cooled to the cooling turner 1. The conveyor 7 is situated in such a way that the conveying elements, such as rollers, of the conveyor 7 are on the side of the cooling turner 1 and above the prong row 28. The direction of travel of the conveyor 7 is in the direction of the axis of rotation 29. The structure of the conveyor 7 is such that the support prongs 2 are able to rotate through the conveyor 7. The support prongs 2 are able to rotate through the conveyor 7 e.g. between the roller rows of the conveyor 7. There can be incisions on the turnable wheel 27 side of the conveyor 7, through which incisions the support prongs 2 are able to rotate. The apparatus 20 comprises a second conveyor for removing the board 4 or board stack from the cooling turner 1. The second conveyor is situated on the other side of the cooling turner 1, i.e. on the opposite side of the cooling turner 1 with respect to the conveyor 7. The structure of the second conveyor is corresponding to that of the conveyor 7.

In addition, the apparatus 26 comprises a positioning device 10 for transferring the board 4 or board stack to the desired position on the conveyor 7. For minimizing bendings of a board 4, the positioning device 10 is arranged to transfer a board 4 or board stack according to its length to a determined position on the conveyor 7, in which position at least the second end of the board 4 or board stack is beside a support prong 2 of the prong row 28 that is under the conveyor 7 to the amount of a predetermined overshoot 8, or is at the point of said support prong. The positioning device 10 is disposed at either end of the conveyor 7, preferably at that end of the conveyor 7 from which the board or board stack is brought to the conveyor 7, as is presented in Fig. 1.

The positioning device 10 is arranged to move in the direction of the axis of rotation 29. The positioning device 10 comprises a turning beam 23 in the transverse direction of the conveyor, to which beam arms 30 are fixed, onto which arms pressing wheels 21 are installed for supporting the board 4 or board stack. The pressing wheels 21 are fitted above a board 4 or board stack. The turning beam 23 is mounted on bearings at both its ends to vertical beams 31 at the ends of the positioning device 10. The turning beam 23, and thereby the pressing wheels 21, can be turned around the longitudinal axis of the turning beam 23 with an actuator 22, e.g. with a pneumatic cylinder.

The positioning device 10 also comprises traction wheels 18 for displacing the board 4 or board stack. The traction wheels 18 are disposed at the same point in the horizontal direction as the pressing wheels 21. The traction wheels 18 are fitted below the board 4 or board stack. The drive device 17 of the traction wheels 18 is disposed at the end of the turning beam 23. The rotational movement of the drive device 17 is transmitted to the traction wheels, e.g. by means of a shaft and belt transmission disposed under the turning beam 23. The positioning device 10 further comprises a drive motor 11, e.g. a gear-head motor, with which the positioning device 10 is displaced in the direction of the arrow 25, i.e. in the direction of the axis of rotation 29 of the cooling carousel 27. Shafts 14 are connected to the drive motor 11, with which shafts the rotational movement of the drive motor 11 is transmitted to rack drives 12 at the ends of the turning beam 23.

At least one support prong 2 of one or more prong rows of the cooling turner 1 is provided with a support structure 3 for supporting a board 4 or board stack during the turning. The support structure 3 supports the board 4 or board stack or the end of it that is beside the support prong 2. Typically at least one support prong 2 of each prong row 28 of the cooling turner 1 is provided with a support structure 3. The support structures 3 are in different prong rows 28 at the same points in the direction of the axis of rotation 29. The construction of a support structure 3 will be described in more detail hereinafter.

In the embodiment according to the drawings the support prongs 2 that are at the first ends 2.1 of the prong rows 28 of the cooling turner 1 are provided with support structures 3 for supporting a board 4 or board stack. The support structure 3 supports the board 4 or board stack beside the end 2.1 of the prong row 28, i.e. beside the support prong 2 that is at the end 2.1 of the prong row. The support structure 3 is parallel with the axis of rotation 29. In this case it supports the board 4 or board stack beside the end 2.1 of the prong row in the direction of the axis of rotation 29. Typically the length L of the support structure 3 is 0.4-0.6 times the distance d between the adjacent support prongs 2 of a prong row. The support structure 3 extends away from the prong row 28, as is presented in the embodiment according to the drawings. Alternatively, or in addition to this, the support structure 3 can extend in the opposite direction, i.e. towards the support prong 2 beside the prong row 28. In this case the support structure 3 supports the board 4 or board stack, preferably the end of the board 4 or board stack, between the first two or last two support prongs 2 of the prong row 28.

A support structure comprises support spurs 3, such as structural hollow sections, fixed to a support prong 2, said support spurs being at a distance from each other. The distance between adjacent support spurs 3 is typically 200-300 mm. The support spurs 3 extend away from the support prong 2. The support spurs 3 are on the same plane as the support prongs 2 of a prong row 28. The positioning device 10 is disposed in the proximity of the end of a prong row 28 on the support structure 3 side.

In addition, the apparatus 26 comprises a measuring device 32, e.g. a laser scanner, for measuring the length of the board 4 or board stack coming to the cooling turner 1. The measuring device 32 is disposed e.g. above or in connection with a conveyor that is before the conveyor 7. The apparatus 26 also comprises a control system 33, to which the measuring data of the measuring device 32 is transferred. The control system 33 is arranged to determine on the basis of the measuring data of the measuring device 32 such a horizontal position on the conveyor 7 for the board 4 or board stack, in which one end 34 of the board 4 or board stack is at the point of a support structure 3 of a support prong 2 of the prong row 28 that is under the conveyor 7, or beside the support structure 3 to at most the amount of a predetermined overshoot 8, and the second end 35 of the board 4 or board stack is beside one support prong 2 of the prong row 28 to the amount of a predetermined overshoot 8. In addition, the control system 33 is arranged to control the positioning device 10 in such a way that the board 4 or board stack is transferred to the determined position.

The magnitude of the overshoot 8 of the

ends

34, 35 of a board 4 or board stack is determined on the basis of the properties, such as the thickness, rigidity and/or material, of the board 4, or of the boards 4 of the board stack, e.g. experimentally. The magnitude of the overshoot 8 is set to be such that the ends of the boards 4 remain sufficiently straight during the turning movement of the cooling turner 1.

In the following the operation of one preferred embodiment of the invention will be described. Before arriving at the cooling turner 1, the length of a board 4 or of the board stack is measured with a measuring device 32. The measuring data of the measuring device 32 is transferred to the control system 33. The control system 33 determines on the basis of the measuring data, i.e. on the basis of the length of the board 4 or board stack, such a position on the conveyor 7, in which position at least the second end of the board 4 or board stack is beside a support prong 2 of the prong row 28 that is under the conveyor 7 to the amount of a predetermined overshoot 8, or is at the point of the support prong 2. In one embodiment of the invention a position is determined for the board 4 or board stack in which position one end 34 of the board or board stack, i.e. the rear end, is at the point of a support structure 3 of a support prong 2 of the prong row 28 that is under the conveyor 7, or is beside or at the side of the support structure 3 to at most the amount of a predetermined overshoot 8, and the second end 35, i.e. the front end, of the board or board stack is at the point of one support prong 2 of the prong row 28, or is beside or at the side of the support prong 2 to the amount of a predetermined overshoot 8. In addition to the length of a board or board stack, inter alia the dimensions of the cooling turner 1 are used for determining the position of a board 4 or board stack, such as the dimensions of the support structure 3, the distance between adjacent support prongs 2 and the width of the support prongs 2.

The board 4 or board stack to be cooled is transferred towards the conveyor 7 on a second conveyor (not presented). The direction of travel of the board 4 or board stack is presented in Fig. 1 with an arrow 6. The second end, i.e. front end, of the board 4 or board stack displaces to between the pressing wheels 21 of the positioning device 10 and the traction wheels 18 and onwards, pushed by the traction wheels 18, towards the second end 36 of the conveyor 7. When the end 34, i.e. the rear end, of the board 4 or board stack comes to the point, or into the proximity, of the positioning device 10, the traction wheels 18 stop. After this the board 4 or board stack is transferred to the position determined by the control system 33 by moving the positioning device 10 in the direction of the axis of rotation 29, i.e. of the arrow 25, towards the second end 35 of the conveyor 7. When the board 4 or board stack is in the predetermined position, the turning beam 23 is turned upwards, in which case the pressing wheels 21 detach from the surface of the board 4 or board stack. The positioning device 10 is displaced backwards into a position in which the positioning device 10 is not at the point of the board 4 or board stack in the vertical direction. The control system 33 controls the positioning device 10.

After this the cooling carousel 27 of the cooling turner is rotated counterclockwise as viewed from the direction of the arrow 6 of Fig. 1, in which case also the prong rows 28 turn counterclockwise around the axis of rotation 29. The support prongs 2 of the prong row 28 under the conveyor 7 come against the bottom surface of the board 4 or board stack and lift it from the conveyor 7. When the board 4 or board stack is at the desired height above the conveyor 7, the movement of the cooling carousel is stopped and a new board or board stack is transferred onto, and positioned on, the conveyor 7 in the manner described above.

The support prongs 2 of the prong row 28 and the support structure 3 support the board 4 or board stack during the turning. When the board 4 or board stack has turned 180 degrees between the consecutive prong rows 28 of the cooling turner 1, it is lowered onto a discharge conveyor (not presented) on the second side of the cooling turner. After this the board 4 or board stack is generally transferred to the next cooling turner or for stacking. In Figs. 1 and 4 the board 4 or board stack is presented for the sake of clarity with a dashed line in such a way that the structures below it are visible.

It is obvious to the person skilled in the art that the different embodiments of the invention are not limited solely to the examples described above, and that they may therefore be varied within the scope of the claims presented below.

For example, the traction wheels of the positioning device 10 do not need to be movable in the horizontal direction, but instead they can be rigidly installed on the positioning device 10. A belt conveyor can be used as a positioning device instead of pressing wheels or traction wheels, which belt conveyor is fitted against the bottom surface of the board 4 or board stack, or for bringing about the positioning movement rams making a linear movement of a suitable length needed at any given time can be used to push the board or board stack into the desired spot.

The positioning device 10 can alternatively be disposed at the second end 36 of the conveyor 7. In this case in this case the turning prongs 2.2 at the second ends 2.2 of the prong rows 28 are provided with a support structure 3.

In addition, the length of the board 4 or board stack to be brought to the cooling turner 1 might be known without a separate measuring system. The length of the board 4 or board stack can be determined e.g. in connection with sawing.

Instead of, or in addition to, the support prong 2 at the end 2.1, 2.2 of a prong row 28, the support prong beside the support prong that is at the end of the prong row 28 can be provided with a support structure 3. The support structure 3 extends towards the support prong 2 at the end 2.1, 2.2 of a prong row 28. In this case the support structure 3 supports the board 4 or board stack, preferably the end of the board 4 or board stack, between the first two or last two support prongs 2 of the prong row 28. The support structure 3 can correspond structurally to the support structure of the support prong 2 at the end 2.1, 2.2 of the prong row 28.

Claims

Method for cooling boards (4) or board stacks in a cooling apparatus (26), which comprises a cooling turner (1), in which are prong rows (28) formed by support prongs (2), between which prong rows a board (4) or board stack to be cooled can be fitted and which prong rows are arranged to rotate around a common axis of rotation (29), and a conveyor (7) for bringing the board or board stack to the cooling turner (1), which conveyor (7) is arranged on the side of the cooling turner and above the prong row (28), and in which method individual boards (4) or board stacks are brought to the conveyor (7) for feeding into the cooling turner (1), characterized in that at least one support prong (2) of at least one prong row (28) is provided with a support structure (3), with which a board (4) or board stack is supported during the turning for minimizing the bendings of the board (4) or board stack.
Method according to claim 1, characterized in that the board (4) or board stack is transferred with the positioning device (10) to the determined position on the conveyor (7) on the basis of the length of the board (4) or board stack, in which position one end of the board (4) or board stack is at the point of a support prong (2) provided with a support structure (3) of the prong row (28) that is under the conveyor (7), or at the point of the support structure (3) of said support prong, or beside the support structure (3) to the amount of a predetermined overshoot, and the second end of the board (4) or board stack is beside one support prong (2) of the prong row (28) to the amount of a predetermined overshoot (8) or at the point of the support prong (2).
Method according to claim 1 or 2, characterized in that the support prong (2) at the end (2.1) of the prong row (28) and/or the support prong that is beside the support prong (2) at the end (2.1) is provided with a support structure (3) for supporting the board (4) or board stack beside the end (2.1) of the prong row (28) and/or between the support prongs (2).
Method according to any of the preceding claims, characterized in that the magnitude of the overshoot (8) is determined on the basis of the properties, such as the thickness, rigidity and/or material, of the board (4) or boards of the board stack.
Method according to any of the preceding claims, characterized in that the positioning device (10) is moved in the direction of the axis of rotation (29) of the prong rows (28) for transferring the board (4) or board stack to the determined position.
Apparatus (26) for cooling boards (4), which apparatus (26) comprises a cooling turner (1), in which are prong rows (28) formed by support prongs (2), between which prong rows a board (4) or board stack to be cooled can be fitted and which prong rows are adapted to rotate around a common axis of rotation (29), and also a conveyor (7) for bringing the board or board stack to the cooling turner (1), which conveyor (7) is arranged on the side of the cooling turner and above the prong row (28), characterized in that the apparatus (26) comprises a positioning device (10) for transferring the board (4) or board stack to the desired position on the conveyor (7), and in that at least one support prong (2) of at least one prong row (28) is provided with a support structure (3) for supporting the board (4) or board stack during the turning.
Apparatus according to claim 6, characterized in that the support prong (2) at the end (2.1) of the prong row (28) and/or the support prong that is beside the support prong (2) at the end (2.1) is provided with a support structure (3) for supporting the board (4) or board stack beside the end (2.1) of the prong row (28) and/or between the support prongs (2).
Apparatus according to claim 6 or 7, characterized in that the positioning apparatus (10) is arranged to transfer a board (4) or board stack according to its length to a determined position on the conveyor (7).
Apparatus according to any of claims 6-8, characterized in that the positioning device (10) is arranged to transfer a board (4) or board stack into a position in which one end of the board (4) or board stack is at the point of a support prong (2) provided with a support structure (3) of the prong row (28) that is under the conveyor (7), or at the point of the support structure (3) of said support prong, or beside the support structure (3) to the amount of a predetermined overshoot, and the second end of the board (4) or board stack is beside one support prong (2) of the prong row (28) to the amount of a predetermined overshoot (8) or at the point of the support prong (2).
Apparatus according to any of the preceding claims, characterized in that the length (L) of the support structure (3) is smaller than the distance (d) between the adjacent support prongs (2) of a prong row (28), typically 0.4-0.6 times the distance (d) between the adjacent support prongs (2) of a prong row (28).
Apparatus according to any of the preceding claims, characterized in that the apparatus comprises a control system (33), which is arranged to determine on the basis of length the position for the board (4) or board stack on the conveyor (7) and to control the positioning device (10) in such a way that the board (4) or board stack is transferred to the determined position.
Apparatus according to claim 11, characterized in that the apparatus comprises a measuring device (32) for measuring the length of the board (4) or board stack coming to the cooling turner, and in that the control system (33) is arranged to determine on the basis of the measuring data of the measuring device (32) the position for the board (4) or board stack.
Apparatus according to any of the preceding claims, characterized in that the positioning device (10) is disposed in the proximity of the end of the prong row (28) on the support structure (3) side.
Apparatus according to any of the preceding claims, characterized in that the positioning device (10) is arranged to move in the direction of the axis of rotation (29) of the prong rows (28).
Apparatus according to any of the preceding claims, characterized in that the positioning device (10) and the support structure (3) are arranged in the proximity of the start end (2.1) or in the proximity of the finish end (2.2) of a prong row (28).
Cooling turner (1) for turning boards (4) or board stacks, in which cooling turner (1) are prong rows (28) formed by support prongs (2), between which prong rows a board (4) or board stack to be cooled can be fitted and which prong rows are adapted to rotate around a common axis of rotation (29), characterized in that at least one support prong (2) of at least one prong row (28) is provided with a support structure (3) for supporting the board (4) or board stack during the turning.
Cooling turner according to claim 16, characterized in that the support prong (2) at the end (2.1) of the prong row (28) and/or the support prong that is beside the support prong (2) at the end (2.1) is provided with a support structure (3) for supporting the board (4) or board stack beside the end (2.1) of the prong row (28) and/or between the support prongs (2).