CN117279761A - Apparatus and method for placing and aligning veneer sheets into veneer sheet stacks in a veneer sheet production process - Google Patents

Abstract

The present invention relates to a method and apparatus for aligning and placing veneer sheets into a veneer sheet stack during the production of veneer sheets in a press. The method here comprises the following method steps: -feeding the veneer (5) on a transport device (1) to a placement area (2) with a fixed or movable base (3) to form a veneer stack (14) or a veneer string (13), -passing the veneer through an alignment area (16) in a transport area (20) of the transport device (1) in order to align the veneer (5) by means of an alignment unit (9) consisting of at least two pairs Ji Daizu which are separately controllable and endless in the transport direction, -measuring the veneer in the transport device (15) before the alignment area (16) or in the alignment area (16) by means of means for position recognition, and-after measuring the position of the veneer, processing the measurement by means of a control device (4) and setting at different speeds to control the alignment strips (6, 7) and the veneer (5) placed thereon until a predefined positioning (1022) of the veneer on the alignment strips (6, 7) is reached.

Description

Apparatus and method for placing and aligning veneer sheets into veneer sheet stacks in a veneer sheet production process

The present invention relates to an apparatus for placing (laying) and aligning (positioning) veneer sheets into a veneer stack (veneer assembly) in a process for producing plywood (veneer) in a press according to the features of patent claim 1.

The invention also relates to a method for placing and aligning veneer sheets into a veneer stack (veneer assembly) in a process for producing plywood (furnieprlatte) in a press according to the features of claim 8.

A method and a device for collecting and feeding a stack of veneer sheets together to a veneer sheet press are known from DE 198 772 C2, in which veneer sheets are aligned and stacked by transport against (relative to) a stop. Sometimes the method and apparatus must be manually supported. Furthermore, the device is very complex and implemented in multiple stages in order to ensure that the stacking (bundling) of the veneer panels is orderly.

Historically, and subsequently with the disclosures of DE 10 2009 021 364 A1, DE 10 2009 021 365 A1, DE 10 2009 021 367 A1 and DE 10 2009 021 368 A1, apparatus and methods for producing veneer stacks at higher speeds were disclosed. The disadvantages of these possibilities are: the veneer edges are damaged or even broken under the influence of the corresponding forces at the quick feed and stop (flap). The fibre direction is also decisive for the design of the system and requires a complex construction for the diametric placement (radial laying) of the layers of fibre direction in the veneer stack.

Furthermore, DE 10 2012 209 929 A1 discloses a device in which the veneer is measured by means of a camera and manipulated and aligned by means of a gripping system. The device, in terms of its construction, meets the current technical requirements of the camera measurement and the corresponding coordinated gripping robot at the level of the prior art, but is characterized by being susceptible to influence and high technical costs. It is conceivable that the orientation of the veneer is independent of the fibre direction. However, due to the tendency of veneer sheets to become thinner, the gripping means can no longer handle these veneer sheets, or the frequency of errors caused by broken veneer sheet portions is unacceptable. This method is not possible with glued veneers.

Apart from the usual possibility of pressing in a circulating press for producing the veneer stacks, veneer strings (veneer strips) can also be formed from veneers or veneer stacks laid one after the other, as is shown in DE 35 40 567 A1 or DE 196 27 024 A1.

In principle, no separate alignment of the veneer without a stop is provided in these publications. As explained in the criticism above, the veneer is thinner and more sensitive. However, even without corresponding predefinations, the aim is to create a gentle (protective) and at the same time automatic handling so that the transport device with the alignment function can align the veneer according to the predefinations, irrespective of the fibre direction of the veneer. At the same time, it should be avoided that the interior of the veneer is subjected to a relief or tension due to externally introduced bending forces, which during production would lead to partial damage or detachment of the veneer at the gaps (holes, defects, etc.) associated with the process technology and the method technology.

The object of the present invention is to propose an apparatus and a method by means of which the veneer can be aligned more gently (better protectively) and more automatically on the transport path for the controlled subsequent laying of the veneer onto the placement position to form a veneer stack or veneer string (veneer strip).

In an extension of this object, an apparatus and a method for aligning a veneer should be developed which are capable of aligning the position of the veneer with a conveyor and of targeted laying, irrespective of the orientation of the fibre orientation of the veneer.

This purpose is also particularly applicable to glued veneers that cannot or are difficult to handle from above.

This object is solved from the apparatus aspect by arranging an apparatus comprising:

a placement area with a fixed or movable base (support, base plate) for receiving the veneer and for stacking a plurality of veneer sheets on top of each other into a veneer sheet stack or veneer sheet string (veneer strip section),

transport means for transporting individual veneer panels to the placement area,

an alignment area with alignment units in the area of the transport device for the pre-given positioning of the veneer,

wherein, at least in the alignment area, alignment strips which are arranged spaced apart from one another and can be controlled individually are arranged below the veneer,

at least one device for position detection of a veneer on a transport device in front of or in the alignment area in the transport direction, and

control device for the predefined positioning of a veneer in an alignment region, wherein the control device

-means adapted to process the measurement results of the device for position recognition of the veneer, and

-adapted for differential control of individual alignment strips in the alignment area.

In a further development, a sensor, preferably a contactless sensor and/or an optical sensor, can be arranged in the device for position recognition, which is particularly suitable for determining the position of the longitudinal edge and/or the transverse edge of the veneer. A 3D scanner or camera system is also conceivable, which is adapted to sense the position or location of the veneer.

Alternatively or additionally, at least one device for increasing the friction of the veneer at the transport device by means of a point-by-point, linear and/or planar force introduction can also be arranged in the transport device and/or the alignment (orientation) unit. These devices are used to ensure the transport of the veneer sheet on the conveyor belt and their forces can be introduced into the veneer sheet from the side of the surface opposite the conveyor belt, i.e. from above, or under the veneer sheet by means of a belt or directly applying negative pressure to the veneer sheet.

Thus, for example, a vacuum tank, a vacuum belt, balls, rollers or rolling bodies (rollers) can be arranged in the transport device and/or the alignment unit in order to exert a force on the veneer.

In an alternative embodiment, the control means may be adapted to generate and/or give a description about the quality of the veneer, preferably about the angulation of the longitudinal edges with respect to the transverse edges, by evaluating the measurement results.

Alternatively or additionally, the control device may be operatively connected to at least one handling device or conveying device downstream of the transport device, for example a placement belt for laying the veneer on a base (floor, substrate), or for transmitting the measurement results and/or instructions on the veneer. This information can also be transmitted to a higher level database or control device of the overall production system.

Preferably, at least two devices, preferably negative pressure devices and/or presses (rolling machines), spaced apart from each other for introducing a force into the veneer can be arranged such that: the angle of rotation of the veneer can be adjusted by the spacing of the devices, for example, when the alignment belts are operated at different relative speeds with respect to each other to rotate the veneer.

This object is achieved with a method for aligning and placing veneer sheets into a veneer sheet stack during the production of veneer sheets in a press, the method having the steps of:

feeding the veneer onto a conveyor (veneer to be placed on the conveyor) to a placement area with a fixed or movable base to form a veneer stack or veneer string (veneer strip section/strip) from a plurality of veneer sheets stacked on top of each other,

the veneer sheet is passed through an alignment zone in the transport zone of the transport device in order to align the veneer sheets by means of an alignment unit consisting of at least two pairs Ji Daizu which are separately controllable and endless in the transport direction,

measuring the veneer in the transport device before or in the alignment area by means of the device for position detection, and

after measuring the position of the veneer, the measurement results are processed by means of a control device and the alignment belts and the veneer placed thereon are controlled at different speed settings until the veneer on the alignment belts reaches a predetermined positioning.

Preferably, the measurement of the position of the veneer is performed during the transport movement.

Alternatively or additionally, the positioning of the veneer into the predefined position is performed outside the positioning movement during the deceleration of the transport movement and/or in a relatively stationary state of the veneer.

Particularly preferably, the positioning of the veneer is monitored by a second device for position detection, if necessary regulated.

Alternatively or additionally, the means for position recognition may comprise contactless sensors, preferably optical sensors, which may be used in particular for position recognition of the longitudinal edges and/or the transverse edges of the veneer.

Alternatively or additionally, in the transport device, the veneer can be pressed at least sometimes by means of a negative pressure to the corresponding means for transport in order to increase the static friction, preferably by means of a transport belt/alignment belt which runs over the negative pressure tank and is permeable to the negative pressure.

Alternatively or additionally, at least one device, preferably a rolling body, a roller or a sphere, may be used in the alignment unit for introducing a force into the veneer, preferably point by point and/or linearly. By introducing a force from above, the veneer can be rotated along a point.

Particularly preferably, in the alignment region, the positioning of the veneer in the transverse direction to the transport direction is shifted or adjusted.

Alternatively or additionally, the measured values of the first means and/or the second means for position recognition may be used to check the quality of the veneer, preferably to check the angle of the longitudinal edge with respect to the transverse edge. Of course, it is also conceivable to inspect the surface by means of a camera system in this process.

The alignment unit may be used to bring the veneer to the placement area or the veneer may be transferred by the alignment unit to a suitable device, preferably to a placement belt, for placement of the veneer onto a base in the placement area.

Alternatively or additionally, the measured value of the first and/or second position detection can be transmitted to a handling device or a conveying device downstream of the conveying device.

Alternatively or additionally, at least two devices spaced apart from each other, preferably a negative pressure device and/or a calender, may be used for introducing a force into the veneer, wherein the rotation angle of the veneer during positioning is adjusted by the spacing of the devices.

In a particular embodiment, a plurality of means for introducing forces may be arranged, which are controlled by the control means in accordance with the positioning requirements or in accordance with the detected position of the veneer, or for adjusting the rotation angle of the veneer. The transverse and/or longitudinal positioning in the transport direction can be illustrated and implemented more easily.

In this case, it may be particularly preferable if these means for introducing forces are arranged movably with respect to the horizontal and/or vertical direction in order to flexibly or as desired arrange the rotation points. For example, a rolling body (roller/drum) pressed from above or a suction device resting against the veneer and/or alignment belt from below can introduce a force into the veneer for fixing. "fixed" means not only absolute static fixation, but in the sense of the present invention it means that the introduction of force is sufficient to make a measurement to affect the change in position due to the alignment belt.

In particular, in the case of a force introduced from above, it can be provided that the device is embodied as one or more spike pins. In the case of a plurality of pins, a degree of freedom should be provided in the horizontal plane or in a plane parallel to the positional change of the veneer, for example by means of a swivel joint, whereby the veneer is not damaged by manipulation of the alignment belt.

The control device may also be embodied as a regulating device, preferably a computer system-based regulating device. In particular, it is provided that a computer program product is arranged in the control device for executing the method.

Based on existing or provided measurement techniques and installed controllable equipment (motors, manipulators, drives, gratings, etc.) provision can be made for information data from the equipment to be provided from necessity to a wide range of control devices in order to optimize the process flow and/or the equipment.

In particular, the means for alignment can be operatively connected to a device for optimally and correctly positioning the veneer on the base (floor, substrate) in the placement (placement) area, which device is in this example a (reversible) placement tape. Within the meaning of the invention, the device for alignment also includes the aspect of laying. This means that the control device is also operatively connected to the separate placement belt and/or the movable base if possible, or to their control device and/or drive. This shall also include any sensor technology in this field. The device, in particular also the control device, is thereby not only suitable for alignment, but also for optimal positioning of the veneer on the base or on a laid veneer which has been placed on the base.

In a particularly preferred embodiment, the system base/placement belt in the placement area can be reduced in terms of its automation effort by means of the control device for the alignment device and the measuring technology available here if the control device takes care of the formation of the veneer stacks or veneer strings on the basis of the veneer position data and generates and transmits the necessary control signals and/or regulation (control) signals for the placement of the veneer at the preset positions on the base.

For quality control (quality inspection), however, it may be expedient to provide sensors in the placement area for detecting and controlling the laid veneer, and also for generating possible correction factors which in turn flow into the (input) control device.

As mentioned, the placement (laying) zone can be arranged before the circulation-type press or the continuous-type press. Further details regarding the transportation of the veneer stacks or regarding the production (preparation) of veneer strings have been described essentially in the prior art. In a circulating press, the movable base can be controlled such that a partially existing stack of veneer sheets is moved for each incoming (arriving) veneer sheet, depending on the position of the incoming (arriving) veneer sheet, in order to achieve an optimal lay-down position. In forming a veneer string, it may be necessary to first place a veneer stack having a stepped orientation and then place the veneer stack, by suitable means of transport, onto the veneer string (veneer strip section/strip) that enters the continuously running press, correspondingly.

It is not absolutely necessary that the placement area or its transport direction is arranged transversely to the transport direction of the transport device as in the illustrated embodiment. The placement areas may also be arranged at an angle or in parallel and are typically determined by the space available in the field or other criteria.

Even though the embodiment examples according to the figures reflect preferred embodiments of the apparatus and process flows (method processes), improvements or alternative possibilities are conceivable here and can be combined with one another in a variable manner in support of the various aspects of the invention.

For example, the alignment unit can also be used directly as a placement tape for laying. The veneer piles may be arranged in a preparation area (supply area) before the transport area or transport device, or the system may provide veneer piles in a preferably predefined order and orientation and deliver them to the transport area. This is particularly advantageous if a layered construction of the veneer stack is required, in which the fibre direction is regularly alternating. In the prior art, a separate transport device is required for each fibre direction. Due to the almost contact-free alignment function, stops and special transport means can be dispensed with. However, this does not necessarily mean that these devices cannot be supportively used on demand.

It is also summarised once again that the present apparatus is adapted to process different fibre directions of the veneer. The fibre direction of the veneer can be oriented (aligned) transversely or longitudinally to (along) the transport direction of the transport means, whereas the veneer is gentle (well protected) and correctly aligned.

Further advantageous measures and design configurations of the subject matter of the invention are explained in the dependent claims and in the following description with the aid of the figures.

Drawings

Aspects of a system or apparatus for producing plywood are shown in the sole figures.

Detailed Description

For this purpose, the veneer 5 is supplied in the preparation area 12 in the transport direction 15 and is delivered to the transport device 1. The transport device 1 transports the corresponding veneer 5 along a transport area 20 to a placement area 2 to create a veneer stack 14 on a base (rack, floor, foundation) 3. Purely schematically, a further placement area 3 is shown on the right side in parallel, where a veneer string (veneer strip) 13 can be formed and fed continuously into a continuously running press 19. In contrast, the veneer assembly (veneer stack) 14 is fed into a cyclically operating press 18. The design of the placement area 2 is purely schematic and is not entirely implemented here, just as is the case for the respective presses 18/19. After pressing the veneer stacks 14 or veneer strings 13, plywood (not shown) or pressed veneer strings (not shown) that can be divided into plywood are produced.

The transport area 20 of the transport device 1 is generally adapted to the specifications of the entire system and the specifications of the plywood produced (process requirements). Thus, variable parameters and setting possibilities exist in the transport device 1. However, it is common to arrange the alignment units 9 in an alignment area 16, which alignment area 16 should be a constituent part of the transport area 20. The transport area generally comprises at the beginning in the transport direction 15 the area to which the veneer 5 is handed over or the area to which the veneer 5 arrives and ends with the veneer 5 laid on the base 3 in the placement area 2. The transport region 1 is thus configured as desired. It is particularly preferred that, as shown in this embodiment, a preferably reversible placement tape 10 is arranged which correctly places the veneer at a predetermined position on the base 3. Of course, other manipulators (operators) for this purpose are also conceivable. For example, as described above, the alignment unit 9 may also take on the task of placing the belt 10. However, this is not necessarily recommended in view of the amount of automation.

The veneer arriving from the preparation area 12 is handed over to the transport area 20 and aligned (calibrated/oriented) by the alignment unit 9 in the alignment area 16. For this purpose, the veneer 5 is measured by means of a sensor 11 of the device 8 for position recognition. The measured values are processed in the control device 4 and the alignment belts 6 and 7 are controlled with calculated different speed values to align the veneer 5. The different speed values of the alignment belts 6 and 7 remain unchanged until the veneer 5 is aligned according to the pre-specifications (regulations). Preferably, this alignment (calibration) is performed during a negative acceleration ramp that reduces the speed of the veneer. Alternatively, the alignment belt may brake the veneer 5 to a stationary state and the alignment is performed by moving only one alignment belt 6 or 7. A point-by-point, linear or (flat) plane-like force introduction point may be provided in order to support the aligned movement of the veneer, or in order to create a rotation point (fulcrum).

During or after alignment of the veneer 5, further sensors 11 or second means 17 for position recognition may measure the veneer 5 and/or confirm the alignment (orientation) or position of the veneer 5.

In an advantageous manner and method, it can now be shown that the veneer is provided in the preparation area 12 by an outdated handling hand or even manually, whereas the alignment and placement of the veneer 5 with respect to the veneer stack (veneer bundle) 14 can be shown automatically.

Preferably, the alignment unit 9 is arranged as close as possible to the placement area 2, since each transition to another conveyor belt again results in a change of position with respect to the transport direction 15.

The veneer 5 is generally rectangular with longitudinal edges 21 and transverse edges 22, wherein the longitudinal edges 21 are preferably and essentially arranged transversely to the transport direction 15 of the transport device 1. In the alignment area 16, the oblique veneer 5 arriving there is measured by means of the device 8 for position recognition and its sensor 11, which is then rotated and aligned by the alignment belt 6/7. In this case, the position of the veneer is measured and controlled in a second device 17 for position detection and is then passed to the placement belt 10 and laid on the base 3 in the placement area 2. To illustrate a possible sequence of the veneers 5, veneers with a transversely extending fibre direction (schematically shown) are shown in the preparation area 12, whereas veneers opposite the transport direction 15 have a longitudinally extending fibre direction.

List of reference numerals: ZP1022

1. Transportation device

2. Placement area

3. Base seat

4. Dispersing device

5. Veneer board

6. Alignment tape

7. Alignment tape

8. Means for position recognition 9. Alignment unit 10. Placing tape (reversible)

11. Sensor for detecting a position of a body

12. Preparation area

13. Veneer string

14. Veneer stacking

15. Transport direction

16. Alignment area 17. Means for position identification (second) 18. Press 19. Press (continuous)

20. Transport area

21. Longitudinal edge 22. Transverse edge.

Claims (20)

1. An apparatus for aligning and laying up veneer sheets into a veneer sheet stack or veneer sheet string during the production of plywood sheets in a press (18, 19), the apparatus comprising:

1.1 a placement area (2) with a fixed or movable base (3) for receiving veneer sheets (5) and for forming a veneer sheet stack (14) or veneer sheet string (13) from a plurality of veneer sheets (5) stacked on top of each other,

1.2 a transport device (1) for transporting individual veneer panels (5) to the placement area (2),

1.3 in the region of the transport device (1) there is an alignment region (16) of an alignment unit (9) for the predefined positioning of the veneer (5), wherein the alignment strips (6, 7) which are arranged at a distance from one another and can be controlled individually are arranged below the veneer (5) at least in the alignment region (16),

1.4 at least one device (8, 17) for position detection for detecting the position of the veneer (5) on the transport device (1) in front of the alignment region (16) or in the alignment region (16) in the transport direction (15), and

1.5 a control device (4) for the predetermined positioning of the veneer (5) in the alignment region (16),

wherein the control device (4)

-means (8/17) adapted to process the measurement results of the device (8/17) for position recognition of the veneer (5), and

-a control adapted to differential the individual alignment strips (6, 7) in the alignment area (16).

2. The device according to claim 1, characterized in that a sensor (11), preferably a contactless and/or optical sensor (11), is arranged in the means (8, 17) for position recognition, which is particularly adapted to determine the position of the longitudinal edge (21) and/or the transverse edge (22) of the veneer.

3. The apparatus according to any of the foregoing claims, characterized in that at least one means is arranged in the transport device (1) and/or the orientation unit (9) for increasing the friction of the veneer (5) at the transport device by means of a point-by-point, linear and/or planar force introduction.

4. The apparatus according to any of the foregoing claims, characterized in that a negative pressure tank, a negative pressure belt, balls, rollers or rolling bodies are arranged in the transport device (1) and/or the alignment unit (9) to exert a force on the veneer.

5. The device according to any one of the preceding claims, wherein the control means (4) are adapted to generate and/or give a description about the quality of the veneer, preferably about the angulation of the longitudinal edge (21) with respect to the transverse edge (22), by evaluating the measurement.

6. The apparatus according to any of the foregoing claims, characterized in that the control device (4) is operatively connected to at least one handling device or conveying device downstream of the transport device (1), for example a placement belt (10) for laying the veneer (5) onto a base (3), or for transmitting the measurement results and/or the instructions concerning the veneer (5).

7. The apparatus according to any of the foregoing claims, characterized in that at least two devices, preferably negative pressure devices and/or presses, are arranged spaced apart from each other for introducing a force into the veneer (5), wherein the angle of rotation of the veneer (5) can be adjusted by the spacing of the devices.

8. A method for aligning and placing veneer sheets into a veneer sheet stack during the production of veneer sheets in a press, the method comprising the method steps of:

8.1 feeding the veneer sheet (5) onto a transport device (1) to a placement area (2) with a fixed or movable base (3) to form a veneer sheet stack (14) or veneer sheet string (13) from a plurality of veneer sheets (5) stacked on each other,

8.2 the veneer sheet passes through an alignment zone (16) in a transport zone (20) of the transport device (1) for aligning the veneer sheet (5) by means of an alignment unit (9) consisting of at least two pairs Ji Daizu which can be controlled separately and which circulate endlessly in the transport direction,

8.3 measuring the veneer in the transport device (15) before the alignment area (16) or in the alignment area (16) by means of the device (8, 17) for position recognition, and

8.4 after measuring the position of the veneer, the measurement results are processed by means of a control device (4) and the alignment strips (6, 7) and the veneer (5) placed thereon are controlled at different speed settings until the veneer on the alignment strips (6, 7) reaches a predetermined positioning.

9. A method according to the preceding method claim, characterized in that the measurement of the position of the veneer is performed during the transport movement.

10. Method according to any of the preceding method claims, characterized in that positioning the veneer (5) into a predefined position is performed in addition to the positioning movement during the deceleration of the transport movement and/or in a relatively stationary state of the veneer (5).

11. A method according to any one of the preceding method claims, characterized in that the positioning of the veneer (5) is monitored and, if necessary, regulated by means of a second device (17) for position recognition.

12. Method according to any one of the preceding method claims, characterized in that the means (8, 17) for position recognition comprise non-contact sensors (11), preferably optical sensors, and that these sensors are used in particular for position recognition of the longitudinal edges (21) and/or the transverse edges (22) of the veneer (5).

13. Method according to any of the preceding method claims, characterized in that the veneer is pressed against the corresponding means for transportation in the transportation means (1), at least sometimes by means of negative pressure, in order to increase the static friction.

14. Method according to any one of the preceding method claims, characterized in that at least one device, preferably a rolling body, a roller or a sphere, is used in the alignment unit (9) for introducing a force into the veneer (5), preferably point by point and/or line-like.

15. A method according to any one of the preceding method claims, characterized in that in the alignment area (16) the position of the veneer (5) is shifted or adjusted transversely to the transport means (15).

16. Method according to any of the preceding method claims, characterized in that the measured values of the first and/or second means (8, 17) for position recognition are used for checking the quality of the veneer, preferably for checking the angle of the longitudinal edge (21) with respect to the transverse edge (22).

17. A method according to any one of the preceding method claims, characterized in that the alignment unit (9) is used to bring the veneer sheet to the placement area, or the alignment unit (9) transfers the veneer sheet (5) to a suitable device, preferably to a placement belt (10), for laying the veneer sheet (5) onto a base (3) in the placement area (2).

18. Method according to any of the preceding method claims, characterized in that the measured value of the first and/or second position identification is transmitted to an operating device or a conveying device downstream of the transport device (1).

19. Method according to any of the preceding method claims, characterized in that at least two devices, preferably negative pressure devices and/or calender, are arranged spaced apart from each other for introducing a force into the veneer (5), wherein the rotation angle of the veneer (5) is adjusted during positioning by the spacing of the devices.

20. A method according to any one of the preceding method claims, characterized in that a plurality of means for introducing forces are arranged, which are controlled by the control means (4) in accordance with the need for positioning or in accordance with the detected position of the veneer or for adjusting the angle of rotation of the veneer.