Note: Descriptions are shown in the official language in which they were submitted.
CA 02480976 2004-09-09
SYSTEM FOR POSLTIONING A WORKPIECE
Field of the Invention
This invention relates to the field of devices for positioning a workpiece in
a
sawmill, and more particularly, it relates to a system for positioning a
workpiece.into an optimized
position to produce the highest value or yield of lumber.
Background of the Invention
Log turners, which are also known as "flying log turners", typically comprise
a pair
of elongated vertically oriented spiked rolls which are located on each side
of a transporting
conveyor. The log turner rotates a workpiece, such as a log or a cant, as the
workpiece travels
towards the primary breakdown machines, such as a gang saw. The spiked rolls
of the log turner
are movable laterally towards and away from the centreline of a workpiece,
longitudinally along
the length of the workpiece in an open-and-close operation, and vertically
upwards and downwards
to engage, manipulate, and rotate the workpiece.
As a workpiece travels along the conveyor en route to the primary breakdown
2 0 machines, a an optimizer, using data from a scanner, determines an
optimized position of the
workpiece such that the workpiece, when processed in accordance with the
desired angular
rotation of the optimized position, may generate the highest value or yield of
lumber. To position
the workpiece in the optimized position, motion control data generated by the
s optimizer and
associated programmable logic controller (PLC) initiates movement of the log
turner to rotate the
2 5 workpiece in order to attain the optimized position. Lateral and
longitudinal displacement of the
spiked turning mils brings the rolls into contact with the surfarce of the
workpiece. The vertical
displacement of each spiked roll allows the workpiece to be rotated about its
longitudinal axis.
The log turner rotates the workpiece until the optimized position is achieved.
1
CA 02480976 2004-09-09
During the turning process, surface irregularities such as protruding knots or
indentations on the surface of the workpiece may affect proper contact of the
spiked rolls with the
workpiece, thereby inhibiting proper rotation of the workpiece to position it
in the optimized
position. This turning inaccuracy results in a significant reduction in lumber
recovery.
Furthermore, even if the optimized position is achieved, movement of the
transport conveyor on
which the workpiece travels may not maintain the workpiece in the optimized
position. Precision
in workpiece rotation and workpiece positioning is made even more difficult
given the speed at
which the log turner performs its function. By providing a system to improve
the accuracy of
workpiece positioning, lumber volume and value will thereby increase.
Summary of the Invention
It is an object of the present invention to provide a system of positioning a
workpiece into an optimized position whereby rotational accuracy of a
workpiece may be
monitored, maintained, and/or corrected so that positional or rotational
errors at primary
breakdown may be avoided, thereby improving overall lumber recovery.
It is another object of the present invention to provide a marking device to
place a
mark on an end of the workpiece to assist the system in monitoring,
maintaining, and/or correcting
2 0 the position of the workpiece such that the optimized position may be
achieved and maintained.
It is another object of the present invention to provide a means for
identifying the
orientation of the mark in real-rime as the workpiece is transported through
the turning mechanism
such that any necessary corrective angular repositioning may be timely
performed to ensure that
2 5 the orientation of the mark prior to the workpiece leaving the turning
mechanism coincides with
the optimized position of the workpiece.
2
CA 02480976 2004-09-09
It is another object of the present invention to provide a evaluator to
determine in
real-time if there are any positional differences between the orientation of
the mark and the
optimized position while the workpiece is being rotated and transported
towards the primary
breakdown machine.
It is a further object of this invention to provide a mechanism for
transmitting
corrective positioning information to control the operation of the turning
mechanism to adjust the
position of the workpiece such that the optimized position may be achieved and
maintained.
The present invention is a system for positioning a workpiece into an
optimized
position. The system includes a marking device adapted to place a mark on the
workpiece prior to
the workpiece passing through an optimizer. A first identifying means
identifies the orientation of
the mark as a point of reference such that the workpiece may be positioned
into the workpiece's
optimized position by rotating the workpiece relative to the orientation of
the mark. A turning
mechanism rotates the workpiece. A second identifying means identifies the
orientation of the
mark while the workpia:e is being rotated. An optimizer or other processor
receives information
from the first identifying means and from the second identifying means to
determine if the
workpiece is in the optimized position. A PLC or other processor controls
rotation of the
2 0 workpiece such that the optimized position of the workpiece may be
achieved.
The marking device may be a spray paint marking device for placing a spray
paint
line on an end of the workpiece. A first earners identifies the orientation of
the mark. This may be
prior to the workpiece exiting the optimizer. The optimizer determines the
optimized position of
2 5 the workpiece. A workpiece turning mechanism such as one including a pair
of turning rolls, one
tuzning roll on each side of a conveyor, rotates the workpiece to its
optimized position. The
turning rolls may be spiked to grasp the workpiece without slipping. The
turning rolls may also
3
CA 02480976 2004-09-09
displace horizontally to engage the workpiece. They may also rotate about a
vertical axis to assist
in transporting the workpiece along the conveyor. The pair of t<unir~g rolls
displace vertically
relative to one another, upwards and downwards, causing the workpiece to
rotate where
sandwiched between the rolls. A second camera may be positioned within the
turning mechanism.
A third camera. may be positioned adjacent to the turning mechanism. The
second and third
cameras identify the orientation of the mark in real-time, continually or at
predetermined time
intervals while the workpiece is being rotated. The real time orientation of
the mark is transmitted
to the processor which compares the real time orientation of the mark with the
desired optimized
position of the workpiece to determine if the workpiece is in the optimized
position. To position
or maintain the workpiece in the optimized position, the processor transmits
information to the
turning mechanism to control rotation of the workpiece such that the optimized
position of the
workpiece may be achieved and maintained.
Brief Description of the Drawin ~~s
Various other objects, features and attendant advantages of the present
invention
will become fully appreciated as the same becomes better understood when
considered in
conjunction with the accompanying drawings, in which like reference characters
designate the
same or similar parts throughout the several views, and wherein:
Figure 1 is a detailed plan view of the infeed, scanner/optimizer; conveyor
and
fuming roll portions of the present invention;
Figure 1 a is a schematic plan view of the present invention;
Figure 2 is a detailed side elevational view of the invention illustrated in
Figure 1;
Figure 3 is an enlarged plan view of a portion of the turning roll mechanism;
4
CA 02480976 2004-09-09
Figure 4 is a sectional view taken on line 4-4 of Figure 3; and
Figure 5 is an enlarged view of a portion of Figure 3.
Detailed Description of Embodimen~~ of the Invention
With reference to the Figures wherein similar characters of reference denote
corresponding parts in each view, a system 10 according to the present
invention includes a
scanner/optimizer 15, a processor 20, a marking device 25, a first and a
second mark orientation
identifying means 30 and 35, and a turning mechanism 40.
As seen in Figures 1 and 1 a, a plurality of workpieces 5 located on an infeed
12 are
transported by suitable means, such as a chainway, in downstream direction of
flow A towards a
conveyor 14. Marking device 25 positionable along infeed 12 is adapted to
place a mark 28 on
each workpiece 5. Alternatively, marking device 25 may be positionable along
conveyor 14 so
that marking device 25 places mark 28 on workpiece S prior to workpiece 5
passing through
scanner/optimizer I5. In a preferred embodiment, not intended to be limiting,
marking device 25
is a spray paint marking device for placing a visually observable spray paint
line on an end 7 of
2 0 workpiece 5. Alternatively, marking device 25 may be a cutting means for
making a superficial
visual cut mark on end 7 of workpiece 5. It will be recognized that there are
many different
marking devices within the scope of the present invention that may be used to
provide a mark on
workpiece 5 as a reference point to provide information regarding the position
of workpiece 5.
2 5 Workpieces 5, which are marked on ends 7, are then transported on conveyor
14 in
downstream direction B towards and through scanner/optimizer 15.
Scanner/optimizer 1 S detects,
analyzes, and classifies the geometrical information and surface
characteristics of each workpiece
5 and determines an optimized cutting solution to obtain optimal lumber
production from each
5
CA 02480976 2004-09-09
workpiece 5. Based on the optimized cutting solution, scanner/optimizer 15
calculates an
optimized position for each workpiece 5 such that workpiece 5 may be
rotatedinto its position
prior to processing. The optimizer may determine the optimized position of
workpiece 5
simultaneously with first identifying means 30 identifying the orientation of
mark 28 on end 7 of
workpiece 5. In one embodiment, first identifying means 30 is a first camera
positionable adjacent
to and in proximity with scanner/optimizer 15 such that end 7 of workpiece S
may be
photographed or scanned prior to end 7 passing through scanner/optimizer 15.
Data relating to the
orientation of mark 28 identified by first identifying means 30 is then
transmitted to processor 20.
The optimized position calculated by scanner/optimizer 15 is also transmitted
to processor 20.
Typically, processor 20 is a computer or a PLC system capable of controlling
turning mechanism
40 to rotate and position workpiece 5 into its optimized position. The
orientation and position of
mark 28 identified by first identifying means 30 serves as a reference point
to assist processor 20
in controlling the rotation of fuming mechanism 40 to position workpiece 5 in
the optimized
position, as described below.
As seen in Figures 3 to 5, turning mechanism 40 comprises a plurality of
turning
rolls 45 located on each side of conveyor 14. Turning rolls 45 are typically
spiked to enable
turning rolls 4S to engage the surface of workpiece 5 to rotate workpiece 5.
As seen in Figuxe 3,
only two pairs of turning rolls 45, one pair on each side of conveyor 14, are
illustrated and is not
2 0 intended to be limiting as two turning rolls 45, one on each side of
conveyor 14, or four or more
even numbered pairs of turning mlls 45 may be employed. Each pair of turning
rolls 45 may
simultaneously rotate about their vertical axis C and/or displace in direction
D laterally of the
direction of flow B, towards and away from the centreline of workpiece 5.
Rotation of turning
rolls 45 about vertical axis C assists with the transport of workpiece 5 along
conveyor 14. Lateral
2 5 displacement of turning rolls 45 in direction B allows turning rolls 45 to
engage the surface of
workpiece 5 of varying widths. To rotate workpiece 5, turning rolls 45 may
also independently
displace vertically upwards and downwards in direction E along their
corresponding vertical axes
C, to thereby rotate workpiece 22 in a clockwise or counter-clockwise
direction, as shown by
6
CA 02480976 2004-09-09
arrow F. Turning rolls 45 are actuated by conventional actuator means such as
hydraulic means
while the rotational, lateral, and vertical movement of turning rolls 45 are
controlled by processor
20. Processor 20 transmits information by conventional means to turning
mechanism 40 to control
actuation of rolls 45 so as to selectively rotate and position workpiece 5
into the optimized
position.
Second identifying means 35 is adapted to monitor the position of mark 28 as
workpiece 5 is rotated by turning mechanism 40. Second identifying means 35
may include a
second camera, wherein the second camera is mounted within turning mechanism
40. In another
embodiment, at least two second identifying means 35 are mounted within
turning mechanism 40, .
as seen in Figure 3. A third identifying means 50, in a preferred embodiment
including a third
camera, is positioned along conveyor 14 where workpiece 5 exits turning
mechanism 40. For
simplicity, and not intending to be limiting, only a single second identifying
means 35 and a single
third identifying means 50 are illustrated in Figure la.
Second and third identifying means 35 and 50 identify the orientation of mark
28
continually or at predetermined time intervals, such as every 5 seconds, and
transmits such real
time information of the orientation of mark 28 to processor 20. Processor 20
performs an
evaluation in real time of any positional differences between the desired
optimized position of
2 0 workpiece 5 and the real time position of workpiece 5, as indicated by
reference to the orientation
of mark 28. If the orientation of mark 28 indicates that workpiece 5 is not in
the optimized
position, processor 20 calculates the required angular rotation of workpiece 5
into position
workpiece 5 in the optimized position and transmits such corrective
information to turning
mechanism 40. Any positional errors of workpiece 5 are thus corrected on a
continual basis until
2 5 workpiece 5 exits turning mechanism 40. If the orientation of mark 28
indicates workpiece 5 is in
the optimized position, processor 20 and turning mechanism 40 cooperates to
maintain workpiece
5 in the optimized position by making any necessary adjustments if workpiece 5
is displaced, for
example, by the movement of conveyor 14.
7
CA 02480976 2004-09-09
In interpreting both this specification and the claims that follow, all terms
should be
interpreted in the broadest possible manner consistent with the context. In
particular, the terms
"comprises" and "comprising" should be interpreted as referring to elements,
components, or steps
in a non-exclusive manner, indicating that the referenced elements,
camponents, or steps may be
present, or utilized, or combined with other elements, components, or steps
that are not expressly
referenced.
As will be apparent to those skilled in the art in the light of the foregoing
disclosure, many alterations and modifications are possible in the practice of
this invention
without departing from the spirit or scope thereof. Accordingly, the scope of
the invention is to be
construed in accordance with the substance defined by the following claims. v
8
