Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27D—WORKING VENEER OR PLYWOOD
  • B27D1/00—Joining wood veneer with any material; Forming articles thereby; Preparatory processing of surfaces to be joined, e.g. scoring
  • B27D1/10—Butting blanks of veneer; Joining same along edges; Preparatory processing of edges, e.g. cutting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H9/00—Registering, e.g. orientating, articles; Devices therefor
  • B65H9/002—Registering, e.g. orientating, articles; Devices therefor changing orientation of sheet by only controlling movement of the forwarding means, i.e. without the use of stop or register wall
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2511/00—Dimensions; Position; Numbers; Identification; Occurrences
  • B65H2511/50—Occurence
  • B65H2511/51—Presence
  • B65H2511/514—Particular portion of element
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2701/00—Handled material; Storage means
  • B65H2701/10—Handled articles or webs
  • B65H2701/13—Parts concerned of the handled material
  • B65H2701/131—Edges
  • B65H2701/1313—Edges trailing edge
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2701/00—Handled material; Storage means
  • B65H2701/10—Handled articles or webs
  • B65H2701/19—Specific article or web
  • B65H2701/1938—Veneer sheet

Definitions

• the present invention relates to a method of aligning veneers during the manufacture of a wood panel, where an aligning table is provided in front of a press, where the veneers are stacked prior to being fed into the press.
• the object of the present invention is to provide a method of ensuring that the panels are right-angled and that an incipient rhombus shape (angle error) is detected and corrected by means of a differential control of the press feed.
• this object is achieved by a distance being established at regular intervals between two consecutive veneers, whereupon the trailing edge of the leading one of said two veneers is detected by means of two photocells arranged along a line perpendicular to the conveying direction and with a certain distance in the longitudinal direction of the veneers, where a possible time difference between the signals emitted by the photocells for detecting the trailing edge is used to change the conveying speed of the veneers on one side compared to the other side, until the time difference is eliminated.
• the present invention also relates to an apparatus for aligning veneers during the manufacture of wood panels, comprising a press, where an aligning table is provided in front of the press, where the veneers can be stacked prior to being fed into the press.
• the apparatus is characterised in that it has a separating mechanism for establishing a distance between two consecutive veneers at regular intervals, and at least two photocells arranged along a line perpendicular to the conveying direction and with a certain distance in the longitudinal direction of the veneers, said photocells being adapted to detect the trailing edge of the veneer, and a differential drive to vary the speed on one side compared to the other side as a function of a possible time difference between the signals emitted by the two photocells, until the time difference is eliminated.
• the signals emitted by the photocells are transmitted to a control unit, said unit computing a possible angle error, with a correction factor being computed based on the angle error.
• the control unit can compute the required difference in speed between the differentially driven motors.
• Fig. 1 shows an apparatus according to the present invention for aligning veneers during the manufacture of a wood panel
• Fig. 2a and Fig. 2b are perspective and lateral views, respectively, of the apparatus.
• Fig. 3 is a lateral view of a conveying mechanism.
• the apparatus shown in Fig. 1 for aligning veneers during the manufacture of a wood panel comprises a press 20.
• an aligning table is arranged, cf. Fig. 2a and Fig. 2b, where the veneers can be stacked prior to being fed into the press 20.
• the veneers are conveyed into the press 20 by means of continuously running subjacent chains 1.
• Fig. 2and Fig. 2b illustrate all six chains 1.
• Said separating mechanism comprises two pneumatic cylinders 3 subjacent to the conveyed veneers with catching devices 2 being mounted at the ends of the piston rods.
• Said catching devices 2 are moved up and lift the veneer in question approximately 2 mm off the chain path.
• the cylinders 3 are suspended on a console 12.
• positive pressure is supplied to a pneumatic cylinder 6 arranged superjacent to the veneers, said cylinder being suspended on a fixedly mounted panel 7.
• the end of the pneumatic cylinder 6 is provided with a panel with rubber friction blocks 4 mounted thereon.
• One motor 22 (MASTER) runs with the line speed of the press 20, while the other motor 23 (SLAVE) runs with the line speed plus/minus the difference in speed computed by the control unit 21 on the basis of the angle error.
• the motors 22, 23 are controlled e. g. by a PID control loop with negative feedback.
• the control After a certain amount of time has passed since the photocells 11 have registered a gap, a signal is transmitted for the cylinders 3, 6 to let go and the veneers positioned behind are conveyed towards the veneers in front.
• a pressure of 1-6 bar is applied via a mechanism illustrated in Fig. 3, said pressure causing the veneers to be pressed down towards the chains 1 to thereby increase friction.
• the mechanism comprises a pneumatic cylinder 9 suspended in a con- sole 10.
• the cylinder 9 presses several wheels 8 down towards the veneers.
• the wheels 8 are suspended in a bogie system, where the wheels 8 are movable in vertical direction, so that there is always one wheel in contact with the veneers, regardless of any minute variation in veneer thickness.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Wood Science & Technology (AREA)
• Forests & Forestry (AREA)
• Veneer Processing And Manufacture Of Plywood (AREA)
• Press Drives And Press Lines (AREA)
• Control Of Presses (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=40228012

Family Applications (1)

Country Status (3)

Citations (2)

• 2007
  • 2007-10-15 DK DK200701482A patent/DK176755B1/da not_active IP Right Cessation
• 2008
  • 2008-10-14 EP EP08801396A patent/EP2212069A1/en not_active Withdrawn
  • 2008-10-14 WO PCT/DK2008/000362 patent/WO2009049623A1/en active Application Filing

Patent Citations (2)

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