CA1146051A - Method and device for feeding timber into a machine for treating timber - Google Patents
Method and device for feeding timber into a machine for treating timberInfo
- Publication number
- CA1146051A CA1146051A CA000370108A CA370108A CA1146051A CA 1146051 A CA1146051 A CA 1146051A CA 000370108 A CA000370108 A CA 000370108A CA 370108 A CA370108 A CA 370108A CA 1146051 A CA1146051 A CA 1146051A
- Authority
- CA
- Canada
- Prior art keywords
- timber
- piece
- measuring
- control
- devices
- 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
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Classifications
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- 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
- B27B1/00—Methods for subdividing trunks or logs essentially involving sawing
- B27B1/007—Methods for subdividing trunks or logs essentially involving sawing taking into account geometric properties of the trunks or logs to be sawn, e.g. curvature
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q35/00—Control systems or devices for copying directly from a pattern or a master model; Devices for use in copying manually
- B23Q35/04—Control systems or devices for copying directly from a pattern or a master model; Devices for use in copying manually using a feeler or the like travelling along the outline of the pattern, model or drawing; Feelers, patterns, or models therefor
- B23Q35/08—Means for transforming movement of the feeler or the like into feed movement of tool or work
- B23Q35/12—Means for transforming movement of the feeler or the like into feed movement of tool or work involving electrical means
- B23Q35/121—Means for transforming movement of the feeler or the like into feed movement of tool or work involving electrical means using mechanical sensing
-
- 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
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Wood Science & Technology (AREA)
- Forests & Forestry (AREA)
- Automation & Control Theory (AREA)
- Manufacture Of Wood Veneers (AREA)
- Length Measuring Devices With Unspecified Measuring Means (AREA)
- Numerical Control (AREA)
Abstract
ABSTRACT
A method and an apparatus for feeding longitudinally moving pieces of timber into a timber processing machine operates according to the prin-ciple that the contours in the longitudinal direction of the piece of timber are first measured by measuring devices which exert minimal pressure on the piece of timber, after which the piece of timber is advanced to at least one control device which is arranged immed-iately adjacent to the processing machine and acts laterally upon the piece of timber with a considerably larger align-ment force. Measurement signals from measuring devices are processed in a conventional manner in a computer from which the order signals are sent to the control unit with a determined delay. The control device operates both as an alignment device, by aligning the piece of timber to the necessary feed attitude calculated in the computer, and as a control device in the stricter sense of the term by controlling the piece of timber while it is being fed into the processing machine.
A method and an apparatus for feeding longitudinally moving pieces of timber into a timber processing machine operates according to the prin-ciple that the contours in the longitudinal direction of the piece of timber are first measured by measuring devices which exert minimal pressure on the piece of timber, after which the piece of timber is advanced to at least one control device which is arranged immed-iately adjacent to the processing machine and acts laterally upon the piece of timber with a considerably larger align-ment force. Measurement signals from measuring devices are processed in a conventional manner in a computer from which the order signals are sent to the control unit with a determined delay. The control device operates both as an alignment device, by aligning the piece of timber to the necessary feed attitude calculated in the computer, and as a control device in the stricter sense of the term by controlling the piece of timber while it is being fed into the processing machine.
Description
1146~Sl The invention relates to a method and apparatus for feeding pieces of timber into a timber processing machine. The expression pieces of timber as used here means elongated lengths of timber which have a centre line and which possess in the lon-gitudinal direction either only outside contours, such as logs, or both outside contours and measurable inside contours such as blocks, planks, and boards. A timber processing machine, which also has a centre line, as referred to herein means a sawing machine, a reducer, a reducing and sawing machine or some other such machine. To achieve the optimum yield from a piece of timber, the piece of timber should be fed into the processing machine in a particular feed attitude, which can be defined, for example, in terms of the position relationship between the centre lines of the piece oftimber and the processing machine.
Methods are known in which thelongitudinal ccntours of a piece of timber are sensed or measured b~ an optical or mechanical measuring system which feeds the measurement results in the form of electrical signals to a computer system in which the optimum yield and the feed attitude required to achieve it is determined, and in which control signals are produced, on the basis of which the piece of timber is lined up in the necessary feed attitude by special alignment devices. An arrangement of this kind is described for example in the applicant's US Patent No. 4,139~035 issued February 13, 1979.
Methods are likewise known in which, for planks and other pieces of timber which, in the longitudinal direction, have inside contours as well as outside contours, the inside contours are used in the computer as a basis for determining the optimum yield, since it is these, and not the outside contours, that determine thevolume of sound wood.
Both optical and mechanical measuring devices for re-cording the outside contours and/or the inside contours are known - 1 - ~
`- 1146~51 an~ are described, for example, in Swedish patent specification ~81,334 published December 1, 1975 and in German Offenlegungsshrift
Methods are known in which thelongitudinal ccntours of a piece of timber are sensed or measured b~ an optical or mechanical measuring system which feeds the measurement results in the form of electrical signals to a computer system in which the optimum yield and the feed attitude required to achieve it is determined, and in which control signals are produced, on the basis of which the piece of timber is lined up in the necessary feed attitude by special alignment devices. An arrangement of this kind is described for example in the applicant's US Patent No. 4,139~035 issued February 13, 1979.
Methods are likewise known in which, for planks and other pieces of timber which, in the longitudinal direction, have inside contours as well as outside contours, the inside contours are used in the computer as a basis for determining the optimum yield, since it is these, and not the outside contours, that determine thevolume of sound wood.
Both optical and mechanical measuring devices for re-cording the outside contours and/or the inside contours are known - 1 - ~
`- 1146~51 an~ are described, for example, in Swedish patent specification ~81,334 published December 1, 1975 and in German Offenlegungsshrift
2,706,149 published August 18, 1977.
The weakest link in all hitherto known arrangements for feeding pieces of timber into a timber processing machine is the mechanical holding or location of the piece of timber when, during the feed sequence, it has already been engaged by the processing tools of the machine, and is thus subjected to the effect of by no means insignificant lateral forces.
However sophisticated the measurement of the geometry of the of the pieces of timber and its relative position may be, the results cannot be more accurate than the performance of the con-trol equipment, and with optical measuring systems in particular, the alignment stage is often a basic weakness.
The present invention overcomes the above-mentioned disadvantage and develops the general concept that the longitudinal contours of the piece of timber (outside contours or, where applicable, outside and inside contours) are to be measured during the longitudinal forward feeding of the piece of timber, i.e. during a forward feeding motion of the same kind as the motion with which the piece of timber is fed into the processing machine, and with measuring devices which do not exert any significant lateral force on the piece of timber (or no force at all).
Alignment is achieved during feeding-in at the same time as guiding, and is performed by devices which apply lateral force to the piece of timber and which ~ointly "re-create" the longitudinal contour form of the piece of timber, calculated in the measuring system, but generally in a corrected position (relative to the centre line of the processing machine). The sawing technique in which a piece of timber with a curved centre line is continuously xotated during feeding about an axis perpendicular to the feed centre line, is also to be possible.
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1146~51 According to the present invention there is provided a method for feeding pieces of timber into a timber processing machine, in which a measuring system longitudinally measures the contours of the piece of timber, and the measurment ~esults are input in the form of electrical measurement signals to a computer system in which, on the basis of these signals and a stored optimisation program, are calculated both the optimum yield that can be obtained from the piece of timber, and the attitude in which the piece of timber must be fed into the pro-cessing maching to achieve this yield, the electrical order sig-nals are generated for aligning the piece of timber with the above-mentioned necessary attitude, in which method the piece of timber is advanced longitudinally on a conveyor arrangement relative to which it is positionally fixed, through the measuring system a~ong the centre line of the conveyor system, and is further conveyed from the measuring system to a control system situated closely adjacent to the processing machine, the piece of timber is advanced longitudinally through the control system along the centre line of the control system, which coincides with the centre line of the processing machine, at a rate defined relative to the feed rate through the measuring sys-tem, the measurement results from the measuring system, containing information on the longitudinal contours of the piece of timber, including the outside contours, and on the position of the said contours relative to the centre line of the measuring system, `. are input to the computer system in the form of at least one continuous sequence of longitudinal contour signals, the control signals are output from the computer in the form of at least one continuous sequence and are fed to the above-mentioned control system for operating its control devices with a delay corresponding to the time taken by a reference point on the piece of timber to
The weakest link in all hitherto known arrangements for feeding pieces of timber into a timber processing machine is the mechanical holding or location of the piece of timber when, during the feed sequence, it has already been engaged by the processing tools of the machine, and is thus subjected to the effect of by no means insignificant lateral forces.
However sophisticated the measurement of the geometry of the of the pieces of timber and its relative position may be, the results cannot be more accurate than the performance of the con-trol equipment, and with optical measuring systems in particular, the alignment stage is often a basic weakness.
The present invention overcomes the above-mentioned disadvantage and develops the general concept that the longitudinal contours of the piece of timber (outside contours or, where applicable, outside and inside contours) are to be measured during the longitudinal forward feeding of the piece of timber, i.e. during a forward feeding motion of the same kind as the motion with which the piece of timber is fed into the processing machine, and with measuring devices which do not exert any significant lateral force on the piece of timber (or no force at all).
Alignment is achieved during feeding-in at the same time as guiding, and is performed by devices which apply lateral force to the piece of timber and which ~ointly "re-create" the longitudinal contour form of the piece of timber, calculated in the measuring system, but generally in a corrected position (relative to the centre line of the processing machine). The sawing technique in which a piece of timber with a curved centre line is continuously xotated during feeding about an axis perpendicular to the feed centre line, is also to be possible.
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1146~51 According to the present invention there is provided a method for feeding pieces of timber into a timber processing machine, in which a measuring system longitudinally measures the contours of the piece of timber, and the measurment ~esults are input in the form of electrical measurement signals to a computer system in which, on the basis of these signals and a stored optimisation program, are calculated both the optimum yield that can be obtained from the piece of timber, and the attitude in which the piece of timber must be fed into the pro-cessing maching to achieve this yield, the electrical order sig-nals are generated for aligning the piece of timber with the above-mentioned necessary attitude, in which method the piece of timber is advanced longitudinally on a conveyor arrangement relative to which it is positionally fixed, through the measuring system a~ong the centre line of the conveyor system, and is further conveyed from the measuring system to a control system situated closely adjacent to the processing machine, the piece of timber is advanced longitudinally through the control system along the centre line of the control system, which coincides with the centre line of the processing machine, at a rate defined relative to the feed rate through the measuring sys-tem, the measurement results from the measuring system, containing information on the longitudinal contours of the piece of timber, including the outside contours, and on the position of the said contours relative to the centre line of the measuring system, `. are input to the computer system in the form of at least one continuous sequence of longitudinal contour signals, the control signals are output from the computer in the form of at least one continuous sequence and are fed to the above-mentioned control system for operating its control devices with a delay corresponding to the time taken by a reference point on the piece of timber to
- 3 ~
~146Q51 travel from a reference point in the measuring system to the corresponding reference point in the control system so that when the piece of timber passes through the control system the external longitudinal contour shape determined in the measuring system is re-created in the control system, but, relative to the centre line of the control system, in a position corrected by calculation on the computer system to the above-mentioned necessary feed attitude, and the piece of timber is fed into the processing machine under forced control by the thus-operated con-trol devices, which are each subjected by an actuating devicewith sufficient force for lateral guiding of the piece of timber.
The present invention also provides an apparatus for feeding pieces of timber into a timber processing machine by the method comprising at least one measuring arrangement to measure the contours of each piece of timber in the longitudinal direction, an alignment arrangement to align the piece of timber to a feed attitude necessary for optimum yield, a computer system to which the measuring and alignment stations are connected and which is arranged to receive measurement signals from the measuring system or systems and to process the measurement signals with the aid of a stored optimisation program into control signals to operate aiignment devices in.the alignment arrangement so that the piece of timber is aligned to the said necessary feed attitude and at least one conveyor arrangement to advance the pieces of timber, in which apparatus the measuring system comprises a conveyor arrangement to advance the piece of timber longitudinally and in a state in which its position is fixed, through the measuring system along the centre line of the measuring system, and at least one measuring device to measure the contours of the piece of timber in the longitudinal direction and to send the measurement results to the computer system in the form of at least one con-tinuous sequence of measurement signals, closely adjacent to the - 3a -processing machine there is arranged a control system which comprises a conveyor arrangement to advance the piece of timber lonc3itudinally through the control system along the centre line whic:h coincides with the centre line of the processing machine and for feeding the piece of timber into the processing machine, and at least one control device which is powered by an actuating device that can be operated by control signals from the computer system, with a force sufficient to displace the piece of timber laterally on the conveyor arrangement and to hold the piece of timber firmly under the action of lateral force acting upon it in the processing machine during processing, the computer system is arranged to output the control signals in the form of at least one continuous sequence of control signals and comprises a delay unit to delay the said output of control signals to the control system by a time corresponding to the time required for a reference point on the piece of timber to travel from a reference point in the measuring system to a corresponding re-ference point in the control system.
The invention will be explained in detail with reference to the accompanying drawings in which:-Fig. 1 is a schematic plan view of a first embodiment of an apparatus according to the invention, Fig. 2 is a schematic plan view of a second, and Fig. 3 of a third embodiment of the present invention, Figs. 4a and 4b show a board with waney edges in two different positions, Fig. 5 shows measurement of the inside and outside contours of a board according to Fig. 4a, and Fig. 6 shows in a diagram examples of the behaviour of the signal obtained in a measuring system.
According to Fig. 1, a log lOA is moved on a longitu-dinal conveyor tchain conveyor) 20 which is driven in the direction - 3b -' 1146~51 of the arrow Pl in a conventional manner, (not shown in the drawing). The log is pressed against the conveyor by one or more retaining rollers 21 above the log with such a force that the log is fixed in position relative to the conveyor.
Log lOA is in the process of passing through a measuring station M in which there is arranged a measuring system that includes two measuring devices, each comprising a pair of contact rollers 22, 23 with vertical spindles 22a, 23a. The pairs of rollers are arranged a distance e apart, where e is preferably 2 m (for the measurement of pieces of timber at least 4 m long).
The contact rollers can move freely transversely to conveyor 20, and pressure devices, for example a helical spring 22b, which for clarity is shown only on contact roller 22, press the contact rollers against log lOA, but with such a small force that the position of the log on conveyor 20, held by retaining roller 21, is not affected. The distance apart of each pair of contact rollers ("the opening width"), and their position relative to the centre line CM of the measuring station is continuously sensed and is fed to a computer D as a continuous sequence of signals from each measuring device. For clarity only the connection between the left-hand contact rollers and the computer have been drawn in Fig. 1, although obviously the positions of the right-hand rollers are fed to the computer.
The forward motion of log lOA
f 30
~146Q51 travel from a reference point in the measuring system to the corresponding reference point in the control system so that when the piece of timber passes through the control system the external longitudinal contour shape determined in the measuring system is re-created in the control system, but, relative to the centre line of the control system, in a position corrected by calculation on the computer system to the above-mentioned necessary feed attitude, and the piece of timber is fed into the processing machine under forced control by the thus-operated con-trol devices, which are each subjected by an actuating devicewith sufficient force for lateral guiding of the piece of timber.
The present invention also provides an apparatus for feeding pieces of timber into a timber processing machine by the method comprising at least one measuring arrangement to measure the contours of each piece of timber in the longitudinal direction, an alignment arrangement to align the piece of timber to a feed attitude necessary for optimum yield, a computer system to which the measuring and alignment stations are connected and which is arranged to receive measurement signals from the measuring system or systems and to process the measurement signals with the aid of a stored optimisation program into control signals to operate aiignment devices in.the alignment arrangement so that the piece of timber is aligned to the said necessary feed attitude and at least one conveyor arrangement to advance the pieces of timber, in which apparatus the measuring system comprises a conveyor arrangement to advance the piece of timber longitudinally and in a state in which its position is fixed, through the measuring system along the centre line of the measuring system, and at least one measuring device to measure the contours of the piece of timber in the longitudinal direction and to send the measurement results to the computer system in the form of at least one con-tinuous sequence of measurement signals, closely adjacent to the - 3a -processing machine there is arranged a control system which comprises a conveyor arrangement to advance the piece of timber lonc3itudinally through the control system along the centre line whic:h coincides with the centre line of the processing machine and for feeding the piece of timber into the processing machine, and at least one control device which is powered by an actuating device that can be operated by control signals from the computer system, with a force sufficient to displace the piece of timber laterally on the conveyor arrangement and to hold the piece of timber firmly under the action of lateral force acting upon it in the processing machine during processing, the computer system is arranged to output the control signals in the form of at least one continuous sequence of control signals and comprises a delay unit to delay the said output of control signals to the control system by a time corresponding to the time required for a reference point on the piece of timber to travel from a reference point in the measuring system to a corresponding re-ference point in the control system.
The invention will be explained in detail with reference to the accompanying drawings in which:-Fig. 1 is a schematic plan view of a first embodiment of an apparatus according to the invention, Fig. 2 is a schematic plan view of a second, and Fig. 3 of a third embodiment of the present invention, Figs. 4a and 4b show a board with waney edges in two different positions, Fig. 5 shows measurement of the inside and outside contours of a board according to Fig. 4a, and Fig. 6 shows in a diagram examples of the behaviour of the signal obtained in a measuring system.
According to Fig. 1, a log lOA is moved on a longitu-dinal conveyor tchain conveyor) 20 which is driven in the direction - 3b -' 1146~51 of the arrow Pl in a conventional manner, (not shown in the drawing). The log is pressed against the conveyor by one or more retaining rollers 21 above the log with such a force that the log is fixed in position relative to the conveyor.
Log lOA is in the process of passing through a measuring station M in which there is arranged a measuring system that includes two measuring devices, each comprising a pair of contact rollers 22, 23 with vertical spindles 22a, 23a. The pairs of rollers are arranged a distance e apart, where e is preferably 2 m (for the measurement of pieces of timber at least 4 m long).
The contact rollers can move freely transversely to conveyor 20, and pressure devices, for example a helical spring 22b, which for clarity is shown only on contact roller 22, press the contact rollers against log lOA, but with such a small force that the position of the log on conveyor 20, held by retaining roller 21, is not affected. The distance apart of each pair of contact rollers ("the opening width"), and their position relative to the centre line CM of the measuring station is continuously sensed and is fed to a computer D as a continuous sequence of signals from each measuring device. For clarity only the connection between the left-hand contact rollers and the computer have been drawn in Fig. 1, although obviously the positions of the right-hand rollers are fed to the computer.
The forward motion of log lOA
f 30
4 1146~)51 through measuring station M is also sensed and fed to the computer D; this can be done either by means of a separate motion detector such as pulse transmitter 16, or by means of retaining roller 21.
In principle only one measuring device is sufficient to measure the longitudinal contours of the piece of timber, but the piece of timber, which may for example be up to 6 m long, must then first pass completely through the measuring device before control can begin. However, this distance is reduced by using several measuring devices in the measuring system, for example two 3 m apart, as shown, or three 2 m apart. A piece of timber 6 m long then has only to be conveyed 3 m or 2 m respectively through the measuring station to be fully measured.
In the rest position contact rollers 22, 23 may be either at a minimum distance apart, smaller than the smallest log diameter, or at a maximum distance apart, greater than the largest log diameter In the first case the measuring process is initiated by the piece of timber forcing the contact rollers apart; in the second it is initiated by a signalling device such as a photocell arrangement 29 signalling that the top end of the piece of timber has arrived at the last measuring device in the direction of feed, after which all the contact rollers in the measuring system are pressed against the piece of timber.
The same conveyor 20 moves log 1OA from measuring station M
to and through a control station I in which the log has the position 1OD, and is then fed into a reducer 11 with two reducing discs 15. The centre line CI of control station I
coincides with the centre line Cg of reducer 11, and in the example shown also with the centre line CM of measuring station M. Since log 1OA, 1OD is being carried all the way on a conveyor 20, the speed of its forward motion through control station I is equal to its speed in measuring station M, and no additional sensors are required. As a general principle, the speed in control station I must be unambigu-ously defined relative to the speed through measuring section M.
In principle only one measuring device is sufficient to measure the longitudinal contours of the piece of timber, but the piece of timber, which may for example be up to 6 m long, must then first pass completely through the measuring device before control can begin. However, this distance is reduced by using several measuring devices in the measuring system, for example two 3 m apart, as shown, or three 2 m apart. A piece of timber 6 m long then has only to be conveyed 3 m or 2 m respectively through the measuring station to be fully measured.
In the rest position contact rollers 22, 23 may be either at a minimum distance apart, smaller than the smallest log diameter, or at a maximum distance apart, greater than the largest log diameter In the first case the measuring process is initiated by the piece of timber forcing the contact rollers apart; in the second it is initiated by a signalling device such as a photocell arrangement 29 signalling that the top end of the piece of timber has arrived at the last measuring device in the direction of feed, after which all the contact rollers in the measuring system are pressed against the piece of timber.
The same conveyor 20 moves log 1OA from measuring station M
to and through a control station I in which the log has the position 1OD, and is then fed into a reducer 11 with two reducing discs 15. The centre line CI of control station I
coincides with the centre line Cg of reducer 11, and in the example shown also with the centre line CM of measuring station M. Since log 1OA, 1OD is being carried all the way on a conveyor 20, the speed of its forward motion through control station I is equal to its speed in measuring station M, and no additional sensors are required. As a general principle, the speed in control station I must be unambigu-ously defined relative to the speed through measuring section M.
5 1146051 Control statlon I is adjacent to reducer 11, and is equipped with a control system consisting of two control devices, each comprising a pair of guide rollers 32, 33, which have vertical spindles such as 33a and which, at least in the parts that come into contact with log 1OD, resemble the corresponding parts of contact rollers 22, 23 in measuring station M.
In this description, control device, control system etc means the arrangements etc that act upon the piece of timber with the combined effect of positioning it in the required feed attitude and keeping it in that attitude during feeding.
Unlike the contact rollers in the measuring station, the guide rollers in the control stàtion are therefore actuated with such a great force that they are able, despite retaining roller 21', to change the position of log 10D
relative to conveyor 20. In the example shown this is achieved by each guide roller or guide roller spindle being carried by the piston rod of double-acting hydraulic cylinder-pi8ton assemblies 34, 35, which are the actuating devices of the control devices. For alignment a device is needed to position the top end of piece of timber 1OD (this is the alignment that is often performed in known arrange-ments). At least one aditional control device is required for possible parallel displacement and/or rotation (around an axis perpendicular to its centre line) of the piece of timber. For alignment of short pieces of timber the distance e' between two adjacent control devices must be less than the shortest length of a piece of timber, which on the other hand leads to problems with the alignment of pieces of timber of maximum length (6 m). It therefore proves particularly advantageous to use at least three control devices 2 m apart, as shown in ~ig. 3.
The activating devices operate in accordance with order signals received from computer system D, which produces the order signals on the basis of a stored program and of the signals rscsivsd from msasuring station ~ and pu1ss :
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transmitter 16. For clarity Fig. 1 shows connections only from computer D to the left-hand actuating devices, bu-t obviously there are the corresponding connections to the right-hand actuating devices.
Such signals from the measuring station are shown in the diagram in Fig. 6, where the abscissa represents -the travel distance of the piece of timber, and the ordinate the measurement signals. The curve A is the midpoint curve of the piece of timber, corresponding to the expression Y(x), whilst the curve ~1 represents one longitudinal outside contour of the piece of timber and F2 the other outside contour.
(y(x) + ( ) ) . . . . . . . . . . . . . . . . . . . (~ ) (y(x) _ (x)) . . . . . . . . . . . . . . . . . . . . (2), where b(x) represents the width curve of the piece of timber.
In principle, measurement can be performed in two ways of equal value, either by recording the outside contours and calculating the midpoint and width, or by recording the midpoint and width and calculating the outside contours.
In computer system D there is stored in a known manner a program for calculation of optimum yield (which need not always be the greatest yield in volume terms) from a piece of timber for which the measurement signals have been received, and of the feed attitude required to obtain the optimum yield. On the basis of the calculation results, the computer D generates order signals to position the piece of timber in control station I to the required feed attitude.
According to the present invention, the computer D is equipped with a delay unit R to which the generated order signals are first fed, and in which their output from computer D is delayed by such an amount that when, for example, a point S' on log 1OD passes through control device 32, ~2, actuating device ~4, ~4 of this control device .
;. , , ,, ., 7 114605~
is controlled by an order signal that was generated on the basis of tne measurement signal that was produced when the point S on log 1OA passed through measuring device 22, 22.
It can thus be said that the control devices "re-create" the longitudinal contour form of the log that was sensed by the rneasuring devices, but with the important difference that it is re-created in a corrected, i.e. changed, position rel-ative to the centre line CI of the control system, compared with the position of the centre line Cv of log 10 relative to the centre line CM of tl1e measuring station. This change of position is the result ^f the optimisation calculation performed in computer D, so that the basically random position of log 10 in measuring station M relative to centre line CM is now corrected to a calculated optimum position relative to centre line CI of control section I, and therefore also relative to centre line Cg of processing machine 11, which is to say that the required feed attitude has been achieved.
The measurement signals can be used in different ways, depending on the design of the processing machine and the type o~ control required. Various control possibilities are stated in more detail at the end of this description. They also include the case of zero correction, in which the computer D determines that the log 10 was already by chance in a position in measuring station M corresponding to the required feed attitude in control station I.
Fig. 1 shows the log 1OD after the position correction has been carried out and the centre line Cv of the log coincides with centre line CI of the control section, which was not the case relative to the centre line CM of the measuring station.
In principle the length of the delay in delay unit R can be determined in two ways. Either a signalling device, for example a photocell arrangement 39, generates a signal which indicates that the top end of log 1OD has arrived at control device 32, 32, this signal is fed to delay unit R and causes the order signals to be issued, or the sequence of signals from pulse transmitter 16 is fed to delay unit R and is used 8 ~4~
there, when the program contains the distance between the measuring station and the control station to determine the instant at which the order signals are issued. It should be noted that in the example according to ~ig. 1, provided that the speed of conveyor 20 is constant, the log moves at the same speed in positions 1OA and 1OD. This means that the order signal sequence must ~e issued at the same rate as the measurement signal sequence was fed in.
At rest, the guide rollers in each pair of guide rollers are the maximum distance apart. At the instant when the top end of log 1OD enters the control device 32, 32, closest to the processing machine 11, the issue of order signals from com-puter D starts, and both guide rollers 32, 32, and guide rollers 33, 33, grip log 10D and hold it firmly under the influence of the order signal sequences that are now being supplied to actuating devices 34, 35 during the entire process of feeding into reducer 11. This effectively pre-vents the unwanted lateral forces occurring in this reducer from laterally deflecting the piece of timber.
~ig. 2 shows an alternative execution in which the meas-uring station and the control station are arranged alongside each other. The connections to and from computer D are indicated only schematically, but are essentially the same as in ~ig. 1. Here the measurement and control stations each have their own longitudinal conveyor 20 and 30 res-pectively. The speed of each conveyor is sensed by pulse transmitters 16' and 16". These speeds need not be identi-cal, since the relationship betwen them can be determined in computer D on the basis of the signals from the two pulse transmitters 16', 16", and thus also the correct rate at which the order signals must be issued, for instance in order that, when a reference point T' passes through control device 33, 33, the control device is subjected to an order signal that was generated on the basis of a measurement signal obtained when the reference point T passed through measuring device 23, 23, regardless of whether conveyors 20 and 30 are moving at equal or different speeds.
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. .
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In principle conveyors 20 and 30 can be mechanically syn-chronised or coupled together and pulse transmitters 16', 16" can be omitted. But there must then be no sliding or slipping, and this can hardly be guaranteed in practice.
As a consequence of the transverse motion between the mea~urement and control stations, a signalling device such as a photocell arrangement 39 is essential here to determine when the output of the order signals is to begin.
The above-mentioned transverse motion is achieved in the following manner. Conveyor 20 feeds piece of timber 10A
into measuring station M in the direction of arrow P1, with the root end forward. After discharge from the discharge end Mu of the measuring station, the piece of timber arrives in a position 10~ on a roller convey~r 37a-37c which extends in the same direction as conveyor 20, and which is crossed by a transverse conveyor which includes three conveyor chains 36a-36c with driver elements. Transverse conveyor 36a-36c may possibly equipped be in a known manner with buf-fer arrangements to regulate the flow at the required rate.
The transverse conveyor move~ the piece of timber in the direction of the arrows P2 to another conveyor 38a-38c which, driven in the direction of arrows P3, runs in the same direction as conveyor 30 of control station I. The drawing shows the piece of timber in a position 10C just before it has reached the above-mentioned second roller conveyor 38a-38c, by which it is then fed top end first into control station I via input end Ii Of the control section.
The piece of timber moves to position 1OD on conveyor 30 and is advanced by conveyor 30 in the direction of arrow P4, as well as being aligned and guided by control devices 32, 33 in the same manner as described in connection with ~ig. 1.
Any rotation of the pieces of timber about a vertical axis during travel between conveyor 20 and conveyor 30 is im-material since it cannot influence the result. On the other hand, the pieces of timber must not rotate about their centre line during this travel, and for this reason the arrangement according to Fig. 2 is best suited for pieces of timber such as boards, planks and blocks, which have a fl!at .
l o li4~
surface resting on the conveyor arrangement.
In view of the fact that the piece of timber can be fed through the measurement and control stations at different speeds, it is evident from ~ig. 2 that one control station can be combined with or can interact with several measuring stations, or that one measuring station can be combined with or can interact with several control stations. As a general rule, timber can be fed faster through a measuring station than through a control station, since the control station also acts as a feed station, and must maintain a working rate that is determined by the feed rate possible in the processing machine.
Fig. 3 shows another, space-saving execution. A log 1 OA, which for clarity is shown in the lower part of the drawing, is fed on a single longitudinal conveyor 20 through a combined measuring and control station MI, arranged immediately adjacent to processing machine 11 . The following devices, in the order corresponding to the direction of motion of conveyor 20, are arranged in the combined station:
a measuring device 41 of essentially the 8ame kind as measuring devices 22, 23, two combined measuring and control devices 42, 43, and a control device of essentially the same kind as control devices 33, 34. The combined measuring and control devices 42, 43 are essen-tially identical to measuring devices 41, but they can also be subjected to the effect of greater force by reason of the fact that they are each subject to the action both of a weak pressure device such as a spring 43d, and an actuating device such as 43e. All devices in section MI are shown to be of a basically known type in which the vertical spindles, such as 41a, of the contact or guide rollers, are fixed to arms such as 41b which in turn are pivoted on spindles such as 41c, and are constantly pressed towards conveyor 20 by weak pressure devices such as coil springs 41d. Control ; devices 44 are subject not to the action of the above-mentioned weak pressure devices, but to the action of actuating devices such as hydraulic-piston assemblies 34'.
These ectuating devices, :uch as actuating devices 43e, S
:, ,: . ' . .:
,.
:g are fully comparable with actuating devices 33 and 34, also with regard to control by order signals from computer D.
When the actuating device is not activated, the combined devices work as measuring devices, and when the actuating device is actuated they work as control devices. The com-puter is informed of the forward feed rate of the piece of timber either by a motion detector or a signalling device.
The arrangement operates in the following manner. ~og lOA
is inserted from the side with its top end at device 43, or is fed to this position longitudinally in the direction of arrow Pl, and measurement then starts. During measurement, which is performed by measuring device 41 and by combined devices 42, 43, all these devices operate as measuring devices, and the actuating devices of combined devices 42, 43 and of control device 44 are deactivated. Log lOA is advanced through the arrangement in the direction of arrow Pl. When the top end of the log reaches control device 44, the entire log has been measured and control can begin.
Combined devices 42, 43 change over to active control, and control device 44 is al~o activated. When the rear end of the log passes device 42 (position lOD), this device is deactivated. When the rear end paase8 device 43, this device is al~o deactivated, thus making the system ready to receive the next log. When the rear end has passed device 44, this device is also deactivated.
Figs. 4a and 4b explain in more detail the process of processing planks, boards, blocks etc which possess longi-tudinally both outside contours H and inside contours G.
Between the outside and inside contours there are inferior waney edge regions V. The usable volume is determined by the clear area B between the inside contours G. The waney edge regions V may be very irregular, so that the centre line Cv of the whole piece of wood does not coincide with the centre line Cg of the clear area B. Only clear area B
with delimiting contours G is of importance for calculating the optimum yield, and the required feed attitude is that shown in Fig. 4b, where the centre line CB Of the clear area coincides with the centre line CR of the machine. However, in the control arrangement board 10' can be gripped by I
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12 ~460S~ ~
control devices 32, 33 only along its outside contours H.
Thus the optimum yield is calculated on the basis of inside contours G, but the order signals for the control devices are generated with respect to outside contours H.
Consequently both the outside and inside contours must be measured in the measuring system and input to computer D.
Fig. 5 shows measurement of the inside contours in two basically known manners. Either mechanical sensors in the form of contact wheels 24 with bevelled surfaces, or a non-contacting optical sensor 45 may be used. The vertical spindles of the contact wheels are mounted on pivoted arms in the same way as arms 41b in Fig. 3, and a known measuring system of this kind is described for example in German patent aplication 27 06 149. The optical sensor 45 is in principle a camera with an objective 46 and an array 47 of light-sensitive devices in the focal plane. A known measur-ing system of this kind, which is described for example in Swedish patent specification 381.334, can measure the inside and outside contours at the same time, so that a measuring section according to the present invention can be equipped only with such mea8uring 8ystem8. The mechanical measurin~
system shown must be supplemented with a measuring system for the outside contours, but mechanical measuring systems that measure both the inside and the outside contours have already been proposed.
Obviously the measuring and control devices need not be of the same typei an optical measuring device may be used alongside a mechanical control device. The essential requirement is that the measuring devices relative to each other and the control devices relative to each other should be equally spaced in the longitudinal direction of the piece of timber. It is also essential that each measuring and control device has a known position relative to the centre lines of the sections in question, even if, as Fig. 2 shows, the centre lines of the measuring and control sections need not coincide. The opening width measured in the measuring system (the distance between contact rollers 22, 2~, 41 within ~ pair) corresponde to the diameter of the piece of ~ ;
; .
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1~
timber, and can be used to advantage for automatic setting Of the tools in proces~ing machine 11, for example to set the po~itions of reducing discs 15 relative to each other.
~he delay in computer D can also be achieved by delaying the input measurement signals before calculation operations are performed, and by then issuing the order signals immediately.
In conclusion, with reference to Fig. 6 and to formulas (1) and (2), seven typical cases will be described, in which ~k represents the order signal to the control devices, rep-resents the measurement signal from the measuring devices and YN a polynomial of degree N: ~
1) yk = o No correction signal. The piece of timber i9 processed along the midpoint curve corresponding to a fixed control device. During processing it i8 subject to large lateral forces caused by irreg-ularities in its outside contours. This is the conventional method, the disadvantages of which it is the purpose of the present invention to eliminate.
2) yk = y The correction signal is equal to the measurement signal. The piece of timber is processed alone the centre line of the measurine section, i.e. the lateral position of the piece of timber relative to the processine machine is not changed. This corresponds to a feeding-in arraneement desiBned in such a way that the piece of timber i9 fixed on the feed conveyor, a method that leads to relatively complex arranee-ments when known technology is used.
3) yk = y - yO (yO = constant) The difference between this and case 2) is that a "best" lateral displacement is calculated, and the piece of timber is processed in a position displaced parallel relative to the centre line of the measuring station In the present description "best"
(adaptation) means an adaptation of a function expression to a given curve such that the spread is as small as pos~ible. The dimension of the spread can be defined in different ways, for example by the least squares sum of all deviations or as the smallest maximum deviation, or by means of a calculation based on the width information obtained at the same time as the midpoint curve. It is also fully conceivable that 3 other measuring systsms msssurs othsr pmrsmeters of the plscs o~
., :.
:
14 1~46Q5~
timber and a "best" processing curve i8 calculated, which is fed to the feeding system according to the present invention.
) yk = y - Yl (Y1 = cO + clx~ .-. cO, c1 = constant) The difference between this case and case 3) is that a "best" rotation is calculated and the piece of timber is proces~ed in a parallel-displaced and rotated position relative to the centre line of the measuring station.
~ yk = y - Y2 (Y2 = cO + clx + c2x2~ .-.-..-. cO, cl, C2 = constant) The difference between this and case 4) is that a "best" parabola is calculated and the piece of timber is now continuously turned while beinB processed. This is a form of curve-sawing.
In this description, control device, control system etc means the arrangements etc that act upon the piece of timber with the combined effect of positioning it in the required feed attitude and keeping it in that attitude during feeding.
Unlike the contact rollers in the measuring station, the guide rollers in the control stàtion are therefore actuated with such a great force that they are able, despite retaining roller 21', to change the position of log 10D
relative to conveyor 20. In the example shown this is achieved by each guide roller or guide roller spindle being carried by the piston rod of double-acting hydraulic cylinder-pi8ton assemblies 34, 35, which are the actuating devices of the control devices. For alignment a device is needed to position the top end of piece of timber 1OD (this is the alignment that is often performed in known arrange-ments). At least one aditional control device is required for possible parallel displacement and/or rotation (around an axis perpendicular to its centre line) of the piece of timber. For alignment of short pieces of timber the distance e' between two adjacent control devices must be less than the shortest length of a piece of timber, which on the other hand leads to problems with the alignment of pieces of timber of maximum length (6 m). It therefore proves particularly advantageous to use at least three control devices 2 m apart, as shown in ~ig. 3.
The activating devices operate in accordance with order signals received from computer system D, which produces the order signals on the basis of a stored program and of the signals rscsivsd from msasuring station ~ and pu1ss :
,,, ' .
. . .
transmitter 16. For clarity Fig. 1 shows connections only from computer D to the left-hand actuating devices, bu-t obviously there are the corresponding connections to the right-hand actuating devices.
Such signals from the measuring station are shown in the diagram in Fig. 6, where the abscissa represents -the travel distance of the piece of timber, and the ordinate the measurement signals. The curve A is the midpoint curve of the piece of timber, corresponding to the expression Y(x), whilst the curve ~1 represents one longitudinal outside contour of the piece of timber and F2 the other outside contour.
(y(x) + ( ) ) . . . . . . . . . . . . . . . . . . . (~ ) (y(x) _ (x)) . . . . . . . . . . . . . . . . . . . . (2), where b(x) represents the width curve of the piece of timber.
In principle, measurement can be performed in two ways of equal value, either by recording the outside contours and calculating the midpoint and width, or by recording the midpoint and width and calculating the outside contours.
In computer system D there is stored in a known manner a program for calculation of optimum yield (which need not always be the greatest yield in volume terms) from a piece of timber for which the measurement signals have been received, and of the feed attitude required to obtain the optimum yield. On the basis of the calculation results, the computer D generates order signals to position the piece of timber in control station I to the required feed attitude.
According to the present invention, the computer D is equipped with a delay unit R to which the generated order signals are first fed, and in which their output from computer D is delayed by such an amount that when, for example, a point S' on log 1OD passes through control device 32, ~2, actuating device ~4, ~4 of this control device .
;. , , ,, ., 7 114605~
is controlled by an order signal that was generated on the basis of tne measurement signal that was produced when the point S on log 1OA passed through measuring device 22, 22.
It can thus be said that the control devices "re-create" the longitudinal contour form of the log that was sensed by the rneasuring devices, but with the important difference that it is re-created in a corrected, i.e. changed, position rel-ative to the centre line CI of the control system, compared with the position of the centre line Cv of log 10 relative to the centre line CM of tl1e measuring station. This change of position is the result ^f the optimisation calculation performed in computer D, so that the basically random position of log 10 in measuring station M relative to centre line CM is now corrected to a calculated optimum position relative to centre line CI of control section I, and therefore also relative to centre line Cg of processing machine 11, which is to say that the required feed attitude has been achieved.
The measurement signals can be used in different ways, depending on the design of the processing machine and the type o~ control required. Various control possibilities are stated in more detail at the end of this description. They also include the case of zero correction, in which the computer D determines that the log 10 was already by chance in a position in measuring station M corresponding to the required feed attitude in control station I.
Fig. 1 shows the log 1OD after the position correction has been carried out and the centre line Cv of the log coincides with centre line CI of the control section, which was not the case relative to the centre line CM of the measuring station.
In principle the length of the delay in delay unit R can be determined in two ways. Either a signalling device, for example a photocell arrangement 39, generates a signal which indicates that the top end of log 1OD has arrived at control device 32, 32, this signal is fed to delay unit R and causes the order signals to be issued, or the sequence of signals from pulse transmitter 16 is fed to delay unit R and is used 8 ~4~
there, when the program contains the distance between the measuring station and the control station to determine the instant at which the order signals are issued. It should be noted that in the example according to ~ig. 1, provided that the speed of conveyor 20 is constant, the log moves at the same speed in positions 1OA and 1OD. This means that the order signal sequence must ~e issued at the same rate as the measurement signal sequence was fed in.
At rest, the guide rollers in each pair of guide rollers are the maximum distance apart. At the instant when the top end of log 1OD enters the control device 32, 32, closest to the processing machine 11, the issue of order signals from com-puter D starts, and both guide rollers 32, 32, and guide rollers 33, 33, grip log 10D and hold it firmly under the influence of the order signal sequences that are now being supplied to actuating devices 34, 35 during the entire process of feeding into reducer 11. This effectively pre-vents the unwanted lateral forces occurring in this reducer from laterally deflecting the piece of timber.
~ig. 2 shows an alternative execution in which the meas-uring station and the control station are arranged alongside each other. The connections to and from computer D are indicated only schematically, but are essentially the same as in ~ig. 1. Here the measurement and control stations each have their own longitudinal conveyor 20 and 30 res-pectively. The speed of each conveyor is sensed by pulse transmitters 16' and 16". These speeds need not be identi-cal, since the relationship betwen them can be determined in computer D on the basis of the signals from the two pulse transmitters 16', 16", and thus also the correct rate at which the order signals must be issued, for instance in order that, when a reference point T' passes through control device 33, 33, the control device is subjected to an order signal that was generated on the basis of a measurement signal obtained when the reference point T passed through measuring device 23, 23, regardless of whether conveyors 20 and 30 are moving at equal or different speeds.
,., ~. ' . . .
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. .
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In principle conveyors 20 and 30 can be mechanically syn-chronised or coupled together and pulse transmitters 16', 16" can be omitted. But there must then be no sliding or slipping, and this can hardly be guaranteed in practice.
As a consequence of the transverse motion between the mea~urement and control stations, a signalling device such as a photocell arrangement 39 is essential here to determine when the output of the order signals is to begin.
The above-mentioned transverse motion is achieved in the following manner. Conveyor 20 feeds piece of timber 10A
into measuring station M in the direction of arrow P1, with the root end forward. After discharge from the discharge end Mu of the measuring station, the piece of timber arrives in a position 10~ on a roller convey~r 37a-37c which extends in the same direction as conveyor 20, and which is crossed by a transverse conveyor which includes three conveyor chains 36a-36c with driver elements. Transverse conveyor 36a-36c may possibly equipped be in a known manner with buf-fer arrangements to regulate the flow at the required rate.
The transverse conveyor move~ the piece of timber in the direction of the arrows P2 to another conveyor 38a-38c which, driven in the direction of arrows P3, runs in the same direction as conveyor 30 of control station I. The drawing shows the piece of timber in a position 10C just before it has reached the above-mentioned second roller conveyor 38a-38c, by which it is then fed top end first into control station I via input end Ii Of the control section.
The piece of timber moves to position 1OD on conveyor 30 and is advanced by conveyor 30 in the direction of arrow P4, as well as being aligned and guided by control devices 32, 33 in the same manner as described in connection with ~ig. 1.
Any rotation of the pieces of timber about a vertical axis during travel between conveyor 20 and conveyor 30 is im-material since it cannot influence the result. On the other hand, the pieces of timber must not rotate about their centre line during this travel, and for this reason the arrangement according to Fig. 2 is best suited for pieces of timber such as boards, planks and blocks, which have a fl!at .
l o li4~
surface resting on the conveyor arrangement.
In view of the fact that the piece of timber can be fed through the measurement and control stations at different speeds, it is evident from ~ig. 2 that one control station can be combined with or can interact with several measuring stations, or that one measuring station can be combined with or can interact with several control stations. As a general rule, timber can be fed faster through a measuring station than through a control station, since the control station also acts as a feed station, and must maintain a working rate that is determined by the feed rate possible in the processing machine.
Fig. 3 shows another, space-saving execution. A log 1 OA, which for clarity is shown in the lower part of the drawing, is fed on a single longitudinal conveyor 20 through a combined measuring and control station MI, arranged immediately adjacent to processing machine 11 . The following devices, in the order corresponding to the direction of motion of conveyor 20, are arranged in the combined station:
a measuring device 41 of essentially the 8ame kind as measuring devices 22, 23, two combined measuring and control devices 42, 43, and a control device of essentially the same kind as control devices 33, 34. The combined measuring and control devices 42, 43 are essen-tially identical to measuring devices 41, but they can also be subjected to the effect of greater force by reason of the fact that they are each subject to the action both of a weak pressure device such as a spring 43d, and an actuating device such as 43e. All devices in section MI are shown to be of a basically known type in which the vertical spindles, such as 41a, of the contact or guide rollers, are fixed to arms such as 41b which in turn are pivoted on spindles such as 41c, and are constantly pressed towards conveyor 20 by weak pressure devices such as coil springs 41d. Control ; devices 44 are subject not to the action of the above-mentioned weak pressure devices, but to the action of actuating devices such as hydraulic-piston assemblies 34'.
These ectuating devices, :uch as actuating devices 43e, S
:, ,: . ' . .:
,.
:g are fully comparable with actuating devices 33 and 34, also with regard to control by order signals from computer D.
When the actuating device is not activated, the combined devices work as measuring devices, and when the actuating device is actuated they work as control devices. The com-puter is informed of the forward feed rate of the piece of timber either by a motion detector or a signalling device.
The arrangement operates in the following manner. ~og lOA
is inserted from the side with its top end at device 43, or is fed to this position longitudinally in the direction of arrow Pl, and measurement then starts. During measurement, which is performed by measuring device 41 and by combined devices 42, 43, all these devices operate as measuring devices, and the actuating devices of combined devices 42, 43 and of control device 44 are deactivated. Log lOA is advanced through the arrangement in the direction of arrow Pl. When the top end of the log reaches control device 44, the entire log has been measured and control can begin.
Combined devices 42, 43 change over to active control, and control device 44 is al~o activated. When the rear end of the log passes device 42 (position lOD), this device is deactivated. When the rear end paase8 device 43, this device is al~o deactivated, thus making the system ready to receive the next log. When the rear end has passed device 44, this device is also deactivated.
Figs. 4a and 4b explain in more detail the process of processing planks, boards, blocks etc which possess longi-tudinally both outside contours H and inside contours G.
Between the outside and inside contours there are inferior waney edge regions V. The usable volume is determined by the clear area B between the inside contours G. The waney edge regions V may be very irregular, so that the centre line Cv of the whole piece of wood does not coincide with the centre line Cg of the clear area B. Only clear area B
with delimiting contours G is of importance for calculating the optimum yield, and the required feed attitude is that shown in Fig. 4b, where the centre line CB Of the clear area coincides with the centre line CR of the machine. However, in the control arrangement board 10' can be gripped by I
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12 ~460S~ ~
control devices 32, 33 only along its outside contours H.
Thus the optimum yield is calculated on the basis of inside contours G, but the order signals for the control devices are generated with respect to outside contours H.
Consequently both the outside and inside contours must be measured in the measuring system and input to computer D.
Fig. 5 shows measurement of the inside contours in two basically known manners. Either mechanical sensors in the form of contact wheels 24 with bevelled surfaces, or a non-contacting optical sensor 45 may be used. The vertical spindles of the contact wheels are mounted on pivoted arms in the same way as arms 41b in Fig. 3, and a known measuring system of this kind is described for example in German patent aplication 27 06 149. The optical sensor 45 is in principle a camera with an objective 46 and an array 47 of light-sensitive devices in the focal plane. A known measur-ing system of this kind, which is described for example in Swedish patent specification 381.334, can measure the inside and outside contours at the same time, so that a measuring section according to the present invention can be equipped only with such mea8uring 8ystem8. The mechanical measurin~
system shown must be supplemented with a measuring system for the outside contours, but mechanical measuring systems that measure both the inside and the outside contours have already been proposed.
Obviously the measuring and control devices need not be of the same typei an optical measuring device may be used alongside a mechanical control device. The essential requirement is that the measuring devices relative to each other and the control devices relative to each other should be equally spaced in the longitudinal direction of the piece of timber. It is also essential that each measuring and control device has a known position relative to the centre lines of the sections in question, even if, as Fig. 2 shows, the centre lines of the measuring and control sections need not coincide. The opening width measured in the measuring system (the distance between contact rollers 22, 2~, 41 within ~ pair) corresponde to the diameter of the piece of ~ ;
; .
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114~5~
1~
timber, and can be used to advantage for automatic setting Of the tools in proces~ing machine 11, for example to set the po~itions of reducing discs 15 relative to each other.
~he delay in computer D can also be achieved by delaying the input measurement signals before calculation operations are performed, and by then issuing the order signals immediately.
In conclusion, with reference to Fig. 6 and to formulas (1) and (2), seven typical cases will be described, in which ~k represents the order signal to the control devices, rep-resents the measurement signal from the measuring devices and YN a polynomial of degree N: ~
1) yk = o No correction signal. The piece of timber i9 processed along the midpoint curve corresponding to a fixed control device. During processing it i8 subject to large lateral forces caused by irreg-ularities in its outside contours. This is the conventional method, the disadvantages of which it is the purpose of the present invention to eliminate.
2) yk = y The correction signal is equal to the measurement signal. The piece of timber is processed alone the centre line of the measurine section, i.e. the lateral position of the piece of timber relative to the processine machine is not changed. This corresponds to a feeding-in arraneement desiBned in such a way that the piece of timber i9 fixed on the feed conveyor, a method that leads to relatively complex arranee-ments when known technology is used.
3) yk = y - yO (yO = constant) The difference between this and case 2) is that a "best" lateral displacement is calculated, and the piece of timber is processed in a position displaced parallel relative to the centre line of the measuring station In the present description "best"
(adaptation) means an adaptation of a function expression to a given curve such that the spread is as small as pos~ible. The dimension of the spread can be defined in different ways, for example by the least squares sum of all deviations or as the smallest maximum deviation, or by means of a calculation based on the width information obtained at the same time as the midpoint curve. It is also fully conceivable that 3 other measuring systsms msssurs othsr pmrsmeters of the plscs o~
., :.
:
14 1~46Q5~
timber and a "best" processing curve i8 calculated, which is fed to the feeding system according to the present invention.
) yk = y - Yl (Y1 = cO + clx~ .-. cO, c1 = constant) The difference between this case and case 3) is that a "best" rotation is calculated and the piece of timber is proces~ed in a parallel-displaced and rotated position relative to the centre line of the measuring station.
~ yk = y - Y2 (Y2 = cO + clx + c2x2~ .-.-..-. cO, cl, C2 = constant) The difference between this and case 4) is that a "best" parabola is calculated and the piece of timber is now continuously turned while beinB processed. This is a form of curve-sawing.
6) yk = y _ y3 (y~ = cO + clx + c2x2 + c3x3, ..... ---- cO, cl, c2, c3 = constant) The difference between this and case 5) is that a "best" cubic arc is calculated. The curved sawing follows the midpoint curve of the piece of timber better, but this methGd can lead to larger and more abrupt curves on the proce~sed piece.
) yk = y - YN (N > 3, high-degree polynomial) When N is increa~ed, the "best"curve is made to approximate increasingly to the measured midpoint curve, i.e. Y ~ YN. which gives yk ~ o, which finally leads to yk = o, which has already been dealt with in case 1). (A polynomial has been u~ed here to descr-ibe the correction signal, even though this is not necessary, but it is the commone~t and most effective form of function expres~ion).
) yk = y - YN (N > 3, high-degree polynomial) When N is increa~ed, the "best"curve is made to approximate increasingly to the measured midpoint curve, i.e. Y ~ YN. which gives yk ~ o, which finally leads to yk = o, which has already been dealt with in case 1). (A polynomial has been u~ed here to descr-ibe the correction signal, even though this is not necessary, but it is the commone~t and most effective form of function expres~ion).
Claims (19)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for feeding pieces of timber into a timber processing machine, in which a measuring system longitudinally measures the contours of the piece of timber, and the measurement results are input in the form of electrical measurement signals to a computer system in which, on the basis of these signals and a stored optimisation program, are calculated both the optimum yield that can be obtained from the piece of timber, and the attitude in which the piece of timber must be fed into the processing machine to achieve this yield, and electrical order signals are generated for aligning the piece of timber with the above-mentioned necessary attitude, in which method the piece of timber is advanced longitudinally on a conveyor arrangement relative to which it is positionally fixed, through the measuring system along the centre line of the conveyor system, and is further conveyed from the measuring system to a control system situated closely adjacent to the processing machine, the piece of timber is advanced longitudinally through the control system along the centre line of the control system, which coincides with the centre line of the processing machine, at a rate defined relative to the feed rate through the measuring system, the measurement results from the measuring system, containing information on the longitudinal contours of the piece of timber, including the outside contours, and on the position of the said contours relative to the centre line of the measuring system, are input to the computer system in the form of at least one continuous sequence of longitudinal contour signals, the control signals are output from the computer in the form of at least one continuous sequence and are fed to the above-mentioned control system for operating its control devices with a delay corresponding to the time taken by a reference point on the piece of timber to travel from a reference point in the measuring system to the corresponding reference point in the control system so that when the piece of timber passes through the control system the external longitudinal contour shape determined in the measuring system is re-created in the control system, but, relative to the centre line of the control system, in a position corrected by calculation on the computer system to the above-mentioned necessary feed attitude, and the piece of timber is fed into the processing machine under forced control by the thus-operated control devices, which are each subjected by an actuating device with sufficient force for lateral guiding of the piece of timber.
2. A method according to claim 1, for machining of pieces of timber such as planks and boards which possess longi-tudinally, in addition to outside contours, also inside contours, in which both the outside and inside contours are measured in the measuring system and the measurement results are input to the computer system in the form of at least one continuous sequence of outside contour signals and at least one continuous sequence of inside contour signals, and that the yield calculation is performed in the computer system on the basis of the inside contour signals, whilst the control signals for the control system are obtained-with reference to the outside contour signals and on the basis of the result of this calculation.
3. A method according to claim 2, in which at least some of the longitudinal contours of the piece of timber are measured optically in the measuring system.
4. A method according to claim 1, 2 or 3, in which at least some of the longitudinal contours of the piece of timber are measured mechanically in the measuring system by means of measuring devices which act upon the piece of timber with such a small force that the position holding of the piece of timber relative to the conveyor arrangement is not affected, and which, at least in the part that acts upon the piece of timber, ad-vantageously have the same form as the part of the control device or devices that acts upon the piece of timber.
5. A method according to claim 1, in which measurement is performed in at least one measuring station situated at a distance from the processing machine, and alignment is performed in at least one control station separate from the measuring station or stations.
6. A method according to claim 5, in which the piece of timber is fed into the measuring station with its root end forward, is transferred laterally between the measuring and control stations, and is fed into the control station with its top end forward.
7. An apparatus for feeding pieces of timber into a timber processing machine by the method according to claim 1, comprising at least one measuring arrangment to measure the con-tours of each piece of timber in the longitudinal direction, an alignment arrangement to align the piece of timber to a feed attitude necessary for optimum yield, a computer system to which the measuring and alignment stations are connected and which is arranged to receive measurment signals from the mea-suring system or systems and to process the measurement signals with the aid of a stored optimisation program into control signals to operate alignment devices in the alignment arrangement so that the piece of timber is aligned to the said necessary feed attitude, and at least one conveyor arrangement to advance the piece of timber, in which apparatus the measuring system comprises a conveyor arrangement to advance the piece of timber longitudinally and in a state in which its position is fixed, through the measuring system along the centre line of the mea-suring system, and at least one measuring device to measure the contours of the piece of timber in the longitudinal direction and to send the measurement results to the computer system in the form of at least one continuous sequence of measurement signals, closely adjacent to the processing machine there is arranged a control system which comprises a conveyor arrangement to advance the piece of timber longitudinally through the control system along the centre line which coincides with the centre line of the processing maching and for feeding the piece of timber into the processing machine, and at least one control device which is powered by an actuating device that can be operated by control signals from the computer system, with a force sufficient to displace the piece of timber laterally on the conveyor arrangement and to hold the piece of timber firmly under the action of lateral force acting upon it in the pro-cessing machine during processing, the computer system is arranged to output the control signals in the form of at least one con-tinuous sequence of control signals and comprises a delay unit to delay the said output of control signals to the control system by a time corresponding to the time required for a re-ference point on the piece of timber to travel from a reference point in the measuring system to a corresponding reference point in the sontrol system.
8. An apparatus according to claim 7, which comprises at least one motion detector connected to the computer system to measure the forward motion of the piece of timber through the measuring and control systems as a basis for determining the above-mentioned travel and delay times.
9. An apparatus according to claim 7 or 8, in which the measuring system comprises measuring devices to measure both the outside contours and the inside contours in the longitudinal direction of a piece of timber and to issue at least one continuous outside contour signal sequence and at least one continuous inside contour signal sequence, and that the computer system is arranged to perform the yield calculation on the basis of the inside contour signal sequence or sequences and to produce the control signal sequence or sequences on the basis of the result of this calculation and with reference to the outside contour signal sequence or sequences.
10. An apparatus according to claim 7 or 8, in which at least one of the measuring devices in the measuring system is an optical measuring device that operates without contact.
11. An apparatus according to claim 7, in which at least one of the measuring devices in the measuring system is a mechanical measuring device that acts upon the piece of timber with such a small force that the position fixing of the piece of timber on the conveyor arrangement is not affected.
12. An apparatus according to claim 11, in which the said measuring device has at least in the part that acts upon the piece of timber the same form as the part of the control device or devices in the control system that acts or act on the piece of timber.
13. An apparatus according to claim 7, in which the measuring device or devices are arranged in at least one measuring station situated at a distance from the processing ma-chine and the control device or devices are arranged in a control station arranged immediately adjacent to the processing machine.
14. An apparatus according to claim 12, in which in a combined measuring and control station arranged immediately adjacent to the processing machine at least one measuring device, at least one combined measuring and control device and at least one control device are arranged in the stated order, the combined device being arranged to be able to operate selectively as a measuring device acting upon the piece of timber with a low pressure and as a control device acting upon the piece of timber .
with a higher pressure.
with a higher pressure.
15. An apparatus according to claim 14, in which there are arranged in the control station at selected distances apart, in the direction of feed of the piece of timber: one measuring device, two combined measuring and control devices and one control device.
16. An apparatus according to claim 13, in which the measuring station or stations are positioned alongside each other and so that the output end of the measuring station or stations is adjacent to the input end of the control station or stations and a transverse conveyor arrangement is arranged to move the pieces of timber between the said ends of the stations.
17. An apparatus according to claim 7 or 8, in which the control devices, the combined measuring and control devices and where applicable the mechanical measuring devices comprise a pair of interacting contact rollers, have vertical spindles, and a cylindrical or bevelled surface for contact with the piece of timber.
18. An apparatus according to claim 7 or 8, in which the actuating devices for the control devices or for the combined measuring and control devices are double-acting cylinder-piston assemblies supplied with a pressure medium.
19. An apparatus according to claim 7 or 8, in which the distance between measuring devices and between control devices or the combined measuring and control devices is 2 m.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8000893-1 | 1980-02-05 | ||
| SE8000893 | 1980-02-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1146051A true CA1146051A (en) | 1983-05-10 |
Family
ID=20340167
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000370108A Expired CA1146051A (en) | 1980-02-05 | 1981-02-04 | Method and device for feeding timber into a machine for treating timber |
Country Status (8)
| Country | Link |
|---|---|
| AT (1) | AT377220B (en) |
| AU (1) | AU545434B2 (en) |
| CA (1) | CA1146051A (en) |
| DE (1) | DE3103725A1 (en) |
| FI (1) | FI810315L (en) |
| FR (1) | FR2474933B1 (en) |
| GB (1) | GB2068294B (en) |
| NO (1) | NO810377L (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4879752A (en) * | 1987-11-18 | 1989-11-07 | Macmillan Bloedel Limited | Lumber optimizer |
| US5960104A (en) * | 1996-08-16 | 1999-09-28 | Virginia Polytechnic & State University | Defect detection system for lumber |
| US8105009B1 (en) | 2007-05-08 | 2012-01-31 | Wps Industries, Inc. | Econo-optimized board edger |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE8207023D0 (en) * | 1982-12-09 | 1982-12-09 | Kockums Ind Ab | PROCEDURE AND DEVICE FOR PROCESSING CROCHET STOCK |
| AT383078B (en) * | 1983-06-08 | 1987-05-11 | Haeupl Johann | PLANT FOR MACHINING BLACK SLEEVED TREES |
| DE3517714A1 (en) * | 1985-05-17 | 1987-01-22 | Enis Ersue | METHOD FOR THE AUTOMATIC CUTTING OF PLANPARALLEL WORKPIECES, ESPECIALLY FROM WOOD, AND A DEVICE FOR CARRYING OUT THIS METHOD |
| FR2602993A1 (en) * | 1986-08-22 | 1988-02-26 | Bocquet Expl Bureau Etu Indles | METHOD AND DEVICE FOR MEASURING AND POSITIONING A PIECE OF WOOD IN A WOODEN MACHINE OF THE DELIGNING TYPE |
| US4732183A (en) * | 1987-04-20 | 1988-03-22 | Macmillan Bloedel Limited | Method and apparatus for peeling veneer |
| US6991012B2 (en) | 1996-03-21 | 2006-01-31 | Coe Newnes/Mcgehee Inc. | Apparatus for sawing a workpiece |
| AU759749B2 (en) * | 1996-03-21 | 2003-05-01 | Usnr/Kockums Cancar Company | Position-based integrated motion controlled curve sawing |
| WO1997034744A2 (en) * | 1996-03-21 | 1997-09-25 | Newnes Machine Ltd. | Position-based integrated motion controlled curve sawing |
| DE19701028C2 (en) * | 1997-01-15 | 1999-12-30 | Esterer Ag Maschf | Device for trimming wooden cuttings |
| CA2338242C (en) | 2000-02-23 | 2004-07-20 | Cae Electronics Ltd. Cae Electronique Ltee | Active sawguide assembly and method |
| CA2309359C (en) | 2000-04-17 | 2009-07-21 | Cae Mcgehee, Inc. | Log processor and method |
| US6929043B2 (en) | 2001-07-24 | 2005-08-16 | Valley Machine Works Ltd. | Optimized board edger and method of operation thereof |
| EP1724075A3 (en) * | 2004-10-08 | 2011-12-21 | José Luis Godoy Varo | Automatic system and procedure for handling and treatment of natural cork slabs |
| DE102005007934B3 (en) * | 2005-02-10 | 2006-06-01 | Esterer Wd Gmbh & Co. Kg | Directing table for aligning wood products comprises a bearing surface curved in the conveying direction so that a distance measured between a point and the axis in the direction of the longitudinal axis is kept constant |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE687283A (en) * | 1965-09-24 | 1967-03-23 | ||
| IT1118219B (en) * | 1978-05-05 | 1986-02-24 | Celaschi Cost Mecc Cmc | EQUIPMENT FOR MILLING PROFILES IN WOOD PANELS OR SIMILAR MATERIAL |
-
1981
- 1981-02-02 GB GB8103149A patent/GB2068294B/en not_active Expired
- 1981-02-02 AT AT0044581A patent/AT377220B/en not_active IP Right Cessation
- 1981-02-02 AU AU66825/81A patent/AU545434B2/en not_active Ceased
- 1981-02-04 NO NO810377A patent/NO810377L/en unknown
- 1981-02-04 DE DE19813103725 patent/DE3103725A1/en not_active Withdrawn
- 1981-02-04 FI FI810315A patent/FI810315L/en not_active Application Discontinuation
- 1981-02-04 CA CA000370108A patent/CA1146051A/en not_active Expired
- 1981-02-04 FR FR8102139A patent/FR2474933B1/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4879752A (en) * | 1987-11-18 | 1989-11-07 | Macmillan Bloedel Limited | Lumber optimizer |
| US5960104A (en) * | 1996-08-16 | 1999-09-28 | Virginia Polytechnic & State University | Defect detection system for lumber |
| US8105009B1 (en) | 2007-05-08 | 2012-01-31 | Wps Industries, Inc. | Econo-optimized board edger |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2068294B (en) | 1984-02-15 |
| ATA44581A (en) | 1984-07-15 |
| FR2474933B1 (en) | 1985-08-02 |
| GB2068294A (en) | 1981-08-12 |
| AU6682581A (en) | 1981-08-13 |
| FR2474933A1 (en) | 1981-08-07 |
| AU545434B2 (en) | 1985-07-11 |
| AT377220B (en) | 1985-02-25 |
| DE3103725A1 (en) | 1982-01-14 |
| NO810377L (en) | 1981-08-06 |
| FI810315L (en) | 1981-08-06 |
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| MKEX | Expiry |