CA1080090A - Method and apparatus for positioning a piece of timber - Google Patents
Method and apparatus for positioning a piece of timberInfo
- Publication number
- CA1080090A CA1080090A CA278,417A CA278417A CA1080090A CA 1080090 A CA1080090 A CA 1080090A CA 278417 A CA278417 A CA 278417A CA 1080090 A CA1080090 A CA 1080090A
- Authority
- CA
- Canada
- Prior art keywords
- timber
- piece
- positioning
- centering
- cant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27B—SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR
- B27B31/00—Arrangements for conveying, loading, turning, adjusting, or discharging the log or timber, specially designed for saw mills or sawing machines
- B27B31/06—Adjusting equipment, e.g. using optical projection
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Wood Science & Technology (AREA)
- Forests & Forestry (AREA)
- Dovetailed Work, And Nailing Machines And Stapling Machines For Wood (AREA)
Abstract
ABSTRACT
A method and apparatus for positioning a piece of timber, while it is moving towards a cutting machine to obtain an optimum amount of wood from it. The method includes the steps of centering the piece of timber symmetrically with respect to the feeding line, determining its form, computing the position of the piece of timber which gives the best result and positioning it in this position. The centering and positioning of the piece of timber are performed by means acting at the same two points on it.
A method and apparatus for positioning a piece of timber, while it is moving towards a cutting machine to obtain an optimum amount of wood from it. The method includes the steps of centering the piece of timber symmetrically with respect to the feeding line, determining its form, computing the position of the piece of timber which gives the best result and positioning it in this position. The centering and positioning of the piece of timber are performed by means acting at the same two points on it.
Description
-' ~08VQ9(~
~ET~IOD AND APPARATUS FOR POSITIONING A PIECE OF TIMBER
BACKGROUND OF T~E INVENTION
1. Field of invention The present invention relates to a method and apparatus for the positioning of a piece of timber such as a log or cut lumber which is fed to a cutting machine. More particularly, the invention is re-lated to a method and apparatus for positioning a cant before a sawing machine in such a way that an optimum saw yield results.
It is an object of the invention to provide a method and apparatus for positioning a cant which is moving towards a sawing machine, wherein the positioning of the cant is effected automatically by means of a measuring device and a data processing unit without inter-rupting the movement of the cant in the feeding direction.
When a log is recluced to cut lumber a cant with two paralleL sides is flrst made. Thls is nowadays usually done by converting two oppo-site slde segments of the logs lnto chlps in a cant chipper cutting off a side board or sideboards from each side of the log in a sawing machine. After this, the cant is turned, its sides are planed off in a chipper and the cant is divided into boards.
The cant is usually fed to the chipper and the sawing machine centered symmetrically with respect to the feeding line.
It is one disadvantage of the symmetric centering of the cant, that irregularities of the wood~ such as crookedness of tbe logg root swelling, and unevenness of the surface can not be taken into account.
The taper of the logs also causes decreased yields.
The measures of the cut lumber are standardized which means that the sawing operation often has to performed with a setting of the saw blades which is not the most favourable for the si~e of cants ~2-. - :
800~
.. ..
J in question. The settîng of t~e blades can for instance be such that side boards are not o~tained from both sides of the cant if the cant is symmetrically centered. If the cant is moved sideways in relation to the feeding line, a side board can in many cases be obtained also from the other side.
~ET~IOD AND APPARATUS FOR POSITIONING A PIECE OF TIMBER
BACKGROUND OF T~E INVENTION
1. Field of invention The present invention relates to a method and apparatus for the positioning of a piece of timber such as a log or cut lumber which is fed to a cutting machine. More particularly, the invention is re-lated to a method and apparatus for positioning a cant before a sawing machine in such a way that an optimum saw yield results.
It is an object of the invention to provide a method and apparatus for positioning a cant which is moving towards a sawing machine, wherein the positioning of the cant is effected automatically by means of a measuring device and a data processing unit without inter-rupting the movement of the cant in the feeding direction.
When a log is recluced to cut lumber a cant with two paralleL sides is flrst made. Thls is nowadays usually done by converting two oppo-site slde segments of the logs lnto chlps in a cant chipper cutting off a side board or sideboards from each side of the log in a sawing machine. After this, the cant is turned, its sides are planed off in a chipper and the cant is divided into boards.
The cant is usually fed to the chipper and the sawing machine centered symmetrically with respect to the feeding line.
It is one disadvantage of the symmetric centering of the cant, that irregularities of the wood~ such as crookedness of tbe logg root swelling, and unevenness of the surface can not be taken into account.
The taper of the logs also causes decreased yields.
The measures of the cut lumber are standardized which means that the sawing operation often has to performed with a setting of the saw blades which is not the most favourable for the si~e of cants ~2-. - :
800~
.. ..
J in question. The settîng of t~e blades can for instance be such that side boards are not o~tained from both sides of the cant if the cant is symmetrically centered. If the cant is moved sideways in relation to the feeding line, a side board can in many cases be obtained also from the other side.
2. Prior art rn a earlier known method, described in the Swedish publication print 3~6.415 the cant is first centered immediately beore the sawing machine. The position of the cant is then adjusted after having been examined ~y means of sensing devices. In this method the positioning of the cant is effected when the cant stands still with regards to the centering device. The feeding movement has therefore to be interrupted and large gaps appear between consecu-tive cants which restricts the capacity o the sawmill.
The Swedish publication print 307.443 describes a method, wherein a board which is fed to an edger saw is measured while the board is mowing towards the saw but not lateral or angular adjust-ment of the board is performed.
SUMMARY OF THE I~VENTION
According to the invention, a cant can move through the process without change of speed, whereby no gaps between consecutive cants appear and the capacity of the sawing will considerably increase.
The position of the cant is adjusted while it moves lengthwise toward the cutting machine in such a way that a high yield is obtained. The method can be utilized in producing cut lumber from logs, or in ot~er log processing operations.
The objects of ~he invention are attained by a method which includes the steps of centering the cant symmetrically while it is moving towards a cutting machine by means of a centering device which is ~ '` .
. : : . .: ,. . . .
, ; :` : : , ' ,: . . : . . . : . . :; : .
10~009~
acting at two points located at a certain distance from each other along the cant, measuring the form o~ the cant, computing the position which gives an optimum result and moving the cant laterally and angularly into this position by means of a positioning device which acts at the same points as the centering device.
[)ESCRIPTION OF TllE DRAWING
A preferred embodiment of the invention will now be described by way of example, with reference to the accompanying drawing~ wherein:
~ig. 1 shows a side view of an apparatus for carrying out the rnethod in accordance with the invention, and Fig. 2 illustrates the principle of its operation.
DESCRIPTION OF THE INVEN llON
In the drawing the reference numeral I denotes conveyor rolls on which a cant 2 is transported forward with constant speed towards a cutting machine (not shown). When the forward end of the cant is In front of a detector 3, two pairs of centering rolls 4 and 5, which are located at a distance Ll and L2 from the forward end of the cant, . .
center the cant symmetrically in relation to the feeding line A-A.
The form of the cant is determined in one single measuring operation by a measuring device 6 above the cant. The measuring device includes light or Laser beam sources and detector means, which receive laser or light impulses reflected from the surface of the cant, thus pro-viding information about the position of the boundary lines at various points along the cant. The impulses are transferred to a computer, which calculates the optimum position of the cant. The computer has previously been programmed to select the processing schedule which gives the best result considering the crookedness, the size, the length and~the taper of the log. The output signals from the ~ ; ;
computer 7 controls the servo units 10 and 11 which actuate the ~`
': ' .
'' .~ ' :
:: :
.: . .
-- 16)8~)9~
positioning rolls 8 and 9. When the forward end of the cant is in front of a detector 12, the position of the cant will be adjusted by the positioning rolls, which are located at the same distances Ll and L2 from the forward end of the cant as the centering rolls. In Fig. 2 the rant is shown in two consecutive positions, centered 2' and ad-justed 2".
An individual cutting schedule and adjustment of the position is determined for each cant. for which reason an optional yield of the sawn material is achieved. By centering and positioning the cant from the same points. It is possibly to reliably command the processing of the cant.
The invention is not limited to the embodiment illustrated in the drawing and the description. Instead of the shown centering and positionin~ rolls other means can be used, Eor instance rolls which act on the plane surfaces of the cant~ The same means can be used for the centering and positioning meovement without causing a substantial error if its speed is high compared with the feed velocity of the ~ ;
cant. Alternatively the centering means and the positioning means can have one common member which performs two functions, i.e. cen-tering and ad~usting the position of the cant.
The centering and positioning devices have been illustrated as being stationary, but embodiment whLch include movable centering and posi-tioning means~ which move with the cant while adJusting its postion are also possible.
', ~,' .. ': ~ '
The Swedish publication print 307.443 describes a method, wherein a board which is fed to an edger saw is measured while the board is mowing towards the saw but not lateral or angular adjust-ment of the board is performed.
SUMMARY OF THE I~VENTION
According to the invention, a cant can move through the process without change of speed, whereby no gaps between consecutive cants appear and the capacity of the sawing will considerably increase.
The position of the cant is adjusted while it moves lengthwise toward the cutting machine in such a way that a high yield is obtained. The method can be utilized in producing cut lumber from logs, or in ot~er log processing operations.
The objects of ~he invention are attained by a method which includes the steps of centering the cant symmetrically while it is moving towards a cutting machine by means of a centering device which is ~ '` .
. : : . .: ,. . . .
, ; :` : : , ' ,: . . : . . . : . . :; : .
10~009~
acting at two points located at a certain distance from each other along the cant, measuring the form o~ the cant, computing the position which gives an optimum result and moving the cant laterally and angularly into this position by means of a positioning device which acts at the same points as the centering device.
[)ESCRIPTION OF TllE DRAWING
A preferred embodiment of the invention will now be described by way of example, with reference to the accompanying drawing~ wherein:
~ig. 1 shows a side view of an apparatus for carrying out the rnethod in accordance with the invention, and Fig. 2 illustrates the principle of its operation.
DESCRIPTION OF THE INVEN llON
In the drawing the reference numeral I denotes conveyor rolls on which a cant 2 is transported forward with constant speed towards a cutting machine (not shown). When the forward end of the cant is In front of a detector 3, two pairs of centering rolls 4 and 5, which are located at a distance Ll and L2 from the forward end of the cant, . .
center the cant symmetrically in relation to the feeding line A-A.
The form of the cant is determined in one single measuring operation by a measuring device 6 above the cant. The measuring device includes light or Laser beam sources and detector means, which receive laser or light impulses reflected from the surface of the cant, thus pro-viding information about the position of the boundary lines at various points along the cant. The impulses are transferred to a computer, which calculates the optimum position of the cant. The computer has previously been programmed to select the processing schedule which gives the best result considering the crookedness, the size, the length and~the taper of the log. The output signals from the ~ ; ;
computer 7 controls the servo units 10 and 11 which actuate the ~`
': ' .
'' .~ ' :
:: :
.: . .
-- 16)8~)9~
positioning rolls 8 and 9. When the forward end of the cant is in front of a detector 12, the position of the cant will be adjusted by the positioning rolls, which are located at the same distances Ll and L2 from the forward end of the cant as the centering rolls. In Fig. 2 the rant is shown in two consecutive positions, centered 2' and ad-justed 2".
An individual cutting schedule and adjustment of the position is determined for each cant. for which reason an optional yield of the sawn material is achieved. By centering and positioning the cant from the same points. It is possibly to reliably command the processing of the cant.
The invention is not limited to the embodiment illustrated in the drawing and the description. Instead of the shown centering and positionin~ rolls other means can be used, Eor instance rolls which act on the plane surfaces of the cant~ The same means can be used for the centering and positioning meovement without causing a substantial error if its speed is high compared with the feed velocity of the ~ ;
cant. Alternatively the centering means and the positioning means can have one common member which performs two functions, i.e. cen-tering and ad~usting the position of the cant.
The centering and positioning devices have been illustrated as being stationary, but embodiment whLch include movable centering and posi-tioning means~ which move with the cant while adJusting its postion are also possible.
', ~,' .. ': ~ '
Claims (7)
1. A method for positioning a piece of timber for processing by a cutting machine, comprising the steps of centering each piece of timber symmetrically with respect to the feeding line by centering means acting at two points spaced apart along the piece of timber, determining the form of the piece of timber, computing the position of the piece of timber which gives an optimum result, and positioning the piece of timber into said position by means acting at the same points as the centering means, all of said steps being effected generally simultaneously with a lengthwise advancement of the piece of timber toward the cutting machine.
2. A method according to Claim 1, wherein the centering and the positioning is performed by two separate means.
3. A method according to Claim 1, wherein the centering means and the positioning means have one common member per-forming a centering and a positioning function.
4. A method according to Claim 1, wherein the centering means and the positioning means are stationary.
5. A method according to Claim 1, wherein the centering and positioning means are moving with the piece of timber while performing its function.
6. An apparatus for positioning a piece of timber while it is moving towards a cutting machine, comprising two pairs of centering rolls spaced apart along the piece of timber, two pairs of positioning rolls spaced apart along the piece of timber, two detectors for detecting the position of the forward end of the piece of timber, whereby the distances from one detector to the two pairs of centering rolls along the piece of timber is equivalent to the distance from the other detector to the two pairs of positioning rolls.
7. An apparatus according to Claim 6, wherein one of the pairs of centering rolls also performs the function of one of the pairs of positioning rolls.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI761401A FI761401A (en) | 1976-05-19 | 1976-05-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1080090A true CA1080090A (en) | 1980-06-24 |
Family
ID=8510003
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA278,417A Expired CA1080090A (en) | 1976-05-19 | 1977-05-13 | Method and apparatus for positioning a piece of timber |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA1080090A (en) |
| FI (1) | FI761401A (en) |
| SE (1) | SE431623C (en) |
-
1976
- 1976-05-19 FI FI761401A patent/FI761401A/fi not_active Application Discontinuation
-
1977
- 1977-05-13 CA CA278,417A patent/CA1080090A/en not_active Expired
- 1977-05-17 SE SE7705856A patent/SE431623C/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| SE431623C (en) | 1985-12-02 |
| SE7705856L (en) | 1977-11-20 |
| FI761401A (en) | 1977-11-20 |
| SE431623B (en) | 1984-02-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |