Contour line scanner
First Claim
1. Sawmill control apparatus for sensing the contours of a cant having a cross section defined by a pair of opposite broad faces and a pair of opposite side faces, and determining an optimum sawline normal to said broad faces, the apparatus comprising:
- beam-forming means for projecting a pair of lines of light onto each of the opposite side faces of a cant in a common plane parallel to the broad faces of the cant to form contour lines of light lengthwise along the side faces, the lines being substantially narrower than the side faces;
light sensor means directed toward the cant at an angle to said plane for sensing the contour lines and generating an output signal corresponding thereto; and
first means responsive to the output signal for defining, in accordance with said contour lines, a width of the cant along its length;
second means for determining the position of a sawline relative to one of said contour lines to maximize, as a function of said width, the recovery of lumber from the cant;
the beam-forming means being positioned to project said lines onto the sides of the cant at a predetermined position between the broad faces to define a grade line corresponding to a specified grade of lumber;
the second means including means for computing a total value of lumber, as a function of said specified grade, can be sawn from the cant between the contour lines positioned at said grade line.
1 Assignment
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Accused Products
Abstract
An edging system for sawing cants into boards includes a contour line scanner for profiling the cant and determining the combination of board widths of a specified grade which will yield the greatest economic return based on current prices. A pair of fan-like lasers positioned along a conveyor project coplanar lines of light onto the side faces of the cant to form contour lines characterizing the widthwise position and shape of the side faces. An X-Y axis TV camera is positioned above the cant for raster scanning the cant widthwise (X-axis) at close lengthwise (Y-axis) intervals along the cant to detect the contour line. The camera output signal is digitized and input to a microcomputer programed to convert the signal to pairs of digital numbers corresponding to the contour line positions at each interval. Two parallel sawlines are fit between the contour lines, one sawline touching one contour line and the second sawline touching or near the second contour line. Board values, tabulated by grade, width and length of the boards, are stored in the computer memory and used to evaluate possible combinations of standard width boards that can be cut between the contour lines for selecting the combination providing the greatest value. The elevation of the lines of light and the board values used in computing total lumber values are jointly varied for different grades of lumber.
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Citations
16 Claims
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1. Sawmill control apparatus for sensing the contours of a cant having a cross section defined by a pair of opposite broad faces and a pair of opposite side faces, and determining an optimum sawline normal to said broad faces, the apparatus comprising:
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beam-forming means for projecting a pair of lines of light onto each of the opposite side faces of a cant in a common plane parallel to the broad faces of the cant to form contour lines of light lengthwise along the side faces, the lines being substantially narrower than the side faces; light sensor means directed toward the cant at an angle to said plane for sensing the contour lines and generating an output signal corresponding thereto; and first means responsive to the output signal for defining, in accordance with said contour lines, a width of the cant along its length; second means for determining the position of a sawline relative to one of said contour lines to maximize, as a function of said width, the recovery of lumber from the cant; the beam-forming means being positioned to project said lines onto the sides of the cant at a predetermined position between the broad faces to define a grade line corresponding to a specified grade of lumber; the second means including means for computing a total value of lumber, as a function of said specified grade, can be sawn from the cant between the contour lines positioned at said grade line. - View Dependent Claims (2, 3, 4, 5, 7)
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6. A method of economically optimizing the sawing of boards from a cant having a pair of opposite broad faces defining a thickness of the cant and a pair of opposite side faces defining a width of the cant, the method comprising:
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storing current values of boards of different widths for a selected grade of lumber; projecting a thin line of light onto each opposite side face of a cant in a plane parallel to the width of the cant to form a pair of contour lines along the opposite side faces and thereby define a grade line on each side face at a predetermined position spaced between the broad faces of the cant corresponding to said selected grade; sensing the relative positions of the contour lines widthwise of the cant; positioning one of the cant and a first saw for sawing the cant lengthwise normal to said plane along a first sawline at a specified widthwise position inwardly adjacent a first one of the contour lines so as to saw the cant along the first sawline in accordance with the selected grade; determining a second sawline parallel to the first sawline at a widthwise position relative to the second one of said contour lines to maximize, in accordance with the stored values, the aggregate value of boards of the selected grade to be sawn from the cant, and positioning a second saw to saw the cant along the second sawline. - View Dependent Claims (8, 9)
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10. A method of economically optimizing the sawing of boards from a cant having a pair of opposite nonparallel side faces, the method comprising:
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storing current values of lumber of different grades, the grade being determined by a dimensional characteristic of the lumber including an amount of corner truncation and by a nondimensional characteristic of the lumber; storing current values of boards of different widths for a selected grade of lumber; grading the cant in accordance with said nondimensional characteristic to determine its grade; projecting a line of light onto each opposite side face of the cant in a plane parallel to the width of the cant to form a pair of contour lines along the opposite side faces; positioning the lines of light normally to said plane in accordance with said grade to delineate a maximum amount of corner truncation on the side faces of said cant for said grade as a function of said dimensional characteristic; and determining positions of at least two parallel sawlines spaced apart between said contour lines which will produce a maximum value of lumber from the cant, including lumber having said maximum amount of corner truncation. - View Dependent Claims (11, 12)
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13. Sawmill control apparatus for sensing the contours of an irregularly-shaped elongated wooden workpiece and determining an economically optimum sawline, comprising:
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beam-forming means for projecting thin coplanar sheets of light against opposite sides of the workpiece in a predetermined plane extending lengthwise of the workpiece to form a pair of contour lines defining a widthwise dimension of the workpiece and characterizing any irregularities in the workpiece in said plane; matrix sensor means directed normally to said plane and having a two-dimensional field of view for sensing the contour lines at a plurality of intervals along a substantial lengthwise portion of the workpiece and producing a pair of output signals corresponding to the widthwise position of the pair of contour lines at each interval; means responsive to the pairs of output signals at each interval for determining the widthwise positions of the contour lines and computing therefrom an optimum sawline through the workpiece normal to said plane as a function of the widthwise dimension of the workpiece defined in said predetermined plane by said contour lines; and means responsive to the computing means for positioning one of the workpiece and a saw for sawing the workpiece along said optimum sawline. - View Dependent Claims (14, 15, 16)
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Specification