Note: Descriptions are shown in the official language in which they were submitted.
13~937Z
71208-37
A SYSTEM FOR ORIENTING LOGS FOR LUMBER PROCESSING
Fleld of the Inventlon
Thls lnventlon relates to orlentatlon of logs for lumber
processlng and more partlcularly to a method and apparatus for de-
termlnlng a deslred rotatlve posltlon as well as skew posltlon for
the logs.
Back~round of the Inventlon
In processlng a log for produclng lumber, lt ls common
to clamp the log on or ln a saw carrlage or overhead conveyor so
that the log length 15 allgned wlth a saw or saw array. The car-
rlage or conveyor then conveys the log ln one or more passes
through the saw to cut the log lnto flltches or slabs, and gener-
ally a center cant of deslred dlmenslons. There are a number of
varlatlons to the process and a number of dlfferent apparatus that
make up the varlous components, at least ln part dlctated by the
slze of the log belng processed and the type of lumber belng pro-
duced.
A maior concern of the lumber produclng process ln gen-
eral ls that the process maxlmlzes utlllzatlon of the log. It has
long been recognlzed that small angular shlftlng of the log axls
'I X
13~3~Z
relative to the saw's cutting line can dramatically impact this
utilization. (Hereafter this angular positioning of the log axis
is referred to as skew positioning to differentiate it from
rotative positioning of the log to be described hereafter.)
To achieve the desired skew positioning, it has been common
to measure the lateral dimension of the log at spaced positions
along the log length. This enables the development of a model of
the log for computer analysis. A computer computes the potential
lumber production from the log at various skew positions within
the log model and selects a preferred skew position for the log.
Positioning apparatus then repositions the log axis to achieve
the desired skew position. Such repositioning apparatus may be
a part of the carriage mechanism or it may be a separate apparatus
that repositions the log prior to the log being clamped, e.g. in
the overhead conveyor. A process and apparatus for skew positioning
of a log for lumber processing is disclosed in U.S. Patent No.
3,786,968 issued to Mason, et al on June 5, 1973.
Whereas establishing a preferred skew position for a log is
unquestionably beneficial to log utilization, it has been
determined that log utilization can be further improved by
establishing a preferred rotative position for the log. It is
believed that no one, prior to this invention, has suggested the
benefits of analyzing a log for rotative positiôning or provided
13~937Z
71208-37
the method or means for accompllshing a desired rotative posltion-
lng of the log.
Brlef DescrlPtlon of the Inventlon
The preferred embodlment of the present lnvention pro-
vides for the taking of measurements that enables the creation of
a representative model of the entire log configuratlon.
Generatlng a complete log profile ln and of ltself ls not new as
lllustrated ln the commonly asslgned appllcatlon for Canadlan
Patent, Serlal No. 583,~56 flled November 23, 1988. (The computer
analysls of such a complete log model ls provlded as a computer
package under the trade mark Real ShapeTM, a product of the
Applied Theory Dlvlsion of U.S. Natural Resources, Inc. located ln
Corvallls, Oregon.) However, the more advanced form of log analy-
sls for lumber productlon under Real ShapeTM ls applled only as an
lmprovement for skew posltlonlng.
The present lnventlon adds a new dlmenslon to log analy-
sis for lumber productlon. The log ls lnltlally rough centered
and then rotated on an axls provlded by splndles that pln the log
at the rough end centers. Scanners posltloned along the log
length (e.g. at the center and each end) take numerous measure-
ments of the log proflle as the log ls rotated. A three-
dlmenslonal model of the log ls thereby created for computer
analysls. The optlmum flt of lumber pleces to the log model ls
computed. Thls computatlon flnds the best flt of vertlcally and
horlzontally orlented lumber
xl
~ . .
~3~937Z
pieces to each of a number of rotative positions of the log. The
rotative position that produces the optimum fit identifies the
desired rotative position for the log when clamped to the saw
carriage for sawing.
Real Shape* analysis is a very thorough and complex
process, the objective being to identify precisely the exact
rectangular lumber pieces that will optimally fit into a three-
dimensional log model at a specific rotative position of the log.
For determining which rotative position is best, it may not be
necessary or desirable to apply that same level of analysis to
each of the selected rotative positions. For example, a pre-Real
Shape analysis may determine the maximum number of one-inch by
four-inch boards that will fit the log width at each rotative
position, it being presumed that that position will yield the
optimum fit. Other pre-Real Shape tests will likely be developed
and, of course, it may turn out best that a full Real Shape
analysis be applied at each rotative position.
In accordance with the present lnvention there is
provided a method for lumber processing comprising; rotating a log
about its approximate geometric axis, scanning the log at space
positions along its length to obtain orthogonal X-Y dimensional
data at selected angular orientations of the rotating log,
analyzing the various X-Y dimensional data and determining the
angular orientation for a desired cutting pattern to be derived
from the log, and repositioning the angular orientation of the log
for feeding the log through lumber processinq saws aligned to cut
*Trade-Mark
'~
13~937Z
the lumber pieces out of the log according to the desired cutting
pattern.
In accordance with the present invention there is also
provided a system for processing loqs into lumber comprising; a)
first conveyor apparatus for conveying logs laterally, b) a rough
centering apparatus sequentially receiving the logs conveyed by
the first conveyor apparatus and establishing a geometric center
at each end of a log and positioning the established log end
centers at a predetermined location, c) a scanning apparatus
including opposed retractable spindles for end pinning a centered
log at the established log end center locations, drive means for
rotating the spindles and the log thereby, and scanning means
obtaining scan data of log dimensions at spaced po~itions along
the log length and at determined rotative angular positions of the
log, d) a saw means, and conveyor clamping means receiving and
clamping the log in a computer selected rotative position
established for the log following scanning thereof, said conveyor
clamping means conveying the log to the saw means, and adjustable
means adjusting the relative position of the saw and log held by
the conveyor clamping means for cutting multiple slabs from the
log in accordance with a computer selected predetermined cutting
pattern, and e) computer means for collecting the scan data and
from the scan data, determining the desired rotative orientation
of the log and the desired cutting pattern at that rotative
orientation, instructing the drive means for rotating the spindles
to obtain the desired rotative orientation, and instructing the
13~93~2
adjustable means for adjusting the position of the log relative to
the saw for achlevlng the desired cuttlng pattern.
The lnventlon and the preferred embodiment lncorporatlng
that invention wlll be more clearly understood and appreciated by
reference to the following detailed descrlption and drawings.
DescrlPtion of the Drawinas
4b
13G937~
Fiq. 1 is a schematic illustration of a system for orienting
a log for lumber processing in accordance with the present
invention;
Figs. 2a, 2b and 2c demonstrate the operational concept
applied to the system and apparatus of Fig. l;
Fig. 3 is an end view of a preferred embodiment of the
invention:
Fig. 4 is a partial side view of certain of the apparatus
utilized in the system for Fig. 3 as if taken on view lines 4-4
of Fig. 3;
Fig. 5 is a diagrammatic view illustrating a transfer for
transferring a log from the scanning apparatus to the saw carriage
of the system;
Fig. 6 is a side view of the saw carriage of Fig. 5;
Fig. 7 is a top view of the saw carriage of Fig. 6;
13~937Z
Fig. 8 is an end view of the saw carriage of Fig. 5.
Fig. 9 is a schematic illustration of an alternate saw
carriage and transfer mechanism;
Figs. lOa and lOb illustrate a variation of the transfer
mechanism shown in Fig. 5; and
Figs. lla, llb and llc illustrate a further variation of the
transfer mechanism shown in Fig. 5.
Description of the Preferred Embodiment
Reference is first made to Fig. 1 of the drawings. The
function of the paired log end grippers 20 are two-fold. First
the grippers 20 pin the ends with their spindles 28, such pinning
occurring at an axis roughly through the geometric center, tas
determined by a geometric centering device not shown), and the
spindles then rotate the log about said axis for scanning. Such
rotation occurs as indicated by arrow 42 to rotate the log under
series of spaced optical scanners 44. The scanners project a
laser light beam 46 on the log's surface and through its reflection,
determines the precise distance to the log's surface at the point
of impingement. Any number of scanning techniques are available
for this purpose and they need not be restricted to electro-
optical scanners. Mechanical as well as acoustical scanning
13~372
71208-37
devices are avallable. An example of optlcal scannlng $s lllu-
strated ln U.S. Pa~ent No. 4,246,940.
The scanner readlngs are taken at angular lncrements,
e.g. every 15 degrees of rotatlon, and the readlngs are conveyed
to a computer 50 as lndlcated by arrows 48. The log end grlppers
20 are mounted on supports 80 for parallel movement on ways 78 for
transferring the log in a charglng capaclty. The log 18 is thus
transferred to side grlpplng dogs 72 of an overhead conveyor 74
directly from the log end grlppers. The log ls dellvered after
scannlng and after the deslred allgnments have been computed. The
transfer ls thus accompllshed followlng approprlate posltloning of
the log by the end grlppers 20, l.e. the log ls approprlately
posltloned for lumber cuttlng when engaged by the dogs 72.
A very slgnlflcant advantage ls derlved from applylng
the rotatable and ad~ustable scannlng splndles to lumber pro-
cesslng. A log was heretofore analyzed for lumber productlon wlth
the log malntalned at a flxed posltlon rotatlvely. Thus, the log
as lt was dellvered lnto the system, typlcally has flxed X and Y
axes. An assumptlon ls made that the saws wlll cut through the
log parallel to lts flxed Y ax$s. The log ls thoroughly analyzed
and
, ~ .
,~.
13(~937Z
the best pattern of lumber for the log at that rotative orientation
is determined.
However, the rotative position that is utilized is arbitrary
or simply selected by "eye balling", and the best solution will
more likely occur at a different rotative position. Compare
figures 2a and 2b. The log of Figs. 2a and 2b (the same log) has
an arbitrarily selected angular orientation. The cutting pattern
determined for Fig. 2a is a pattern in the traditional X-Y axis
as utilized in prior systems. A better solution may be one such
as that illustrated in Fig. 2b, i.e. at an X'-Y' axis offset by
angle a. The scanning procedure of Fig. 1 would readily make
that determination by taking orthogonal dimensional data at
numerous angular positions of the log, e.g. determined through
Real ShapeTM analysis. From this analysis, a specific X'-Y'
orientation is determined as the best rotative position, and then
the log is repositioned rotatively by the angle a to align the
log relative to the traditional Y axis cuttiDg, i.e. the position
of Fig. 2c.
The preferred embodiment of the invention is illustrated in
Figs. 3 through 8. From Fig. 3, a conveyor 10 of conventional
design conveys logs laterally onto a stop-and-loader 12, also of
conventional design. The scanning apparatus 14 includes geometric
centering V's for rough centering tupper V's 22 and lower V's
13~?937~
24). The logs 18 are sequentially delivered to the stop-and-
loader 12 by the conveyor 10. In turn, each log is rolled from
the stop-and-loader onto the V's 24 of the scanning apparatus,
the lower V's being positioned in their lowered positions and the
upper V's positioned in their upper position as shown in dash
lines in Fig. 3. The loading of the V's is controlled by the
pivotal position of the stop-and-loader 12, shown in the "stop"
position in solid lines and the "loader" position in dash lines.
The V's close to the position in solid lines whereby the log
is positioned so that spindles 16 are geometrically aligned
centrally on the log ends. The spindles 16 are moved inward to
impale the log ends. The V's open and the spindles 16 rotate to
rotate the log 18. Scanners 26 take measurements of the log at
determined angular increments, e.g. every 15 of rotation and
conveys those measurements to a computer 50' as indicated by arrow
30.
The computer then computes the production for each angular
position as previously explained having reference to Figs. 2a,
2b and 2c. When the desired rotative position is determined, the
computer 50' instructs the drive for the spindles (arrow 32) to
rotate the log to that rotative position.
13(:~37~
The computer 50' also determines the desired skew and offset
position for the log 18 in the selected rotative position and
controls the spindles 16 and/or knees 34 of carriage 36 to
accomplish the desired skew and offset positioning of the log.
Because a small log may be sawed only on two offsized sides and
a large log may be sawed on all four sides, accordingly, the
desired skewed position may be calculated for only the x axis for
the large logs. The control over spindles 16 and/or knees 34 will
be accordingly affected. This control phase of the operation
will be subsequently discussed. First however, the transfer of
the log 18 to the clamps 38 of the two knees 34 will be discussed.
A transfer mechanism is schematically illustrated in Fig.
5. The knees 34 are appropriately positioned relative to the log
ends and the clamps are moved into position around the scanning
~pindles 16. As seen in Fig. 5, the clamps 38 are C shaped and
fit around the spindles 16. The clamps are then driven into the
log ends and the spindles 16 are retracted. The knees are retracted
to draw the log, in the selective rotative position, onto the
carriage as shown.
It is at this point that the computer instructs the two end
knees 34 of the carriage as to the desired positions for sawing
slabs off of the log. The computer can precisely dictate and
control independently the position of the two knees to obtain the
13~g372
desired cutting pattern. The carriage itself (Figs. 6 and 7) is
confined to a reciprocal movement as dictated by the tracks 52 and
54 on which the carriage rollers 56 and 58 are entrained. Roller
58 is grooved and rides on the inverted V rail of track 54 to
affix the carriage position relative to the tracks. Fig. 8
illustrates the saw line 40 and it will be understood that whatever
portion of the log is extended over that saw line 40 is sawed from
the log. As each pass is completed, the computer controlled knees
are moved further out, e.g. in two inch increments. When one side
of the log is sawn down to the center cant, the log is pivoted
180 and the sawing operation is repeated for that other side.
Such pivoting is permitted, e.g. by bearings at 35. It is
contemplated that the transfer to the C clamps 38 would occur
with the log 90 offset from its desired rotative position. The
C clamp 38 would rotate 90 in one direction and then 180 back in
the opposite direction in bearing 35.
In some instances, i.e. for larger logs, the log will be
rotated for sawing on all four sides. Boards or flitches ~sometimes
reEerred to as slabs) will be cut continuously off the log until
the center cant is as small as four inches by four inches at one
end ~or both ends). In order to accomplish this total sawing of
a log, it is believed desirable, and perhaps necessary that the
carriage clamps are spindle shaped and are pinned to the log end
to the center of the area designated by the computer as the center
11
13~937~
cant. This requires a different type of transfer mechanism such
as illustrated in Figs. 10 and 11.
The scanning spindles cannot be pinned at a position near
the log end center for holding the log when the clamps of the
carriage are moved in to grip the logs at the same center position.
In Fig. 10, that problem is resolved by providing the scanning
spindles with means for gripping the log end sides and thereby
leaving the end centers exposed for the clamp~. A spindle shaft
16' is fitted with pinchers 110 and a hydraulic cylinder 112 opens
and closes the pinchers 110 to clamp the sides of the log adjacent
the log end. The log is rotated about shaft 16' and then rotatively
positioned. The shaft 16' may be adjusted to center the designated
cant positions of the log ~the four inch square) relative to the
carriage clamp 38' which is moved along a fixed lineal path. The
clamp arms 34' will project between the pinchers as illustrated
in Figs. lOa and lOb. Lateral positioning of the clamps 38' at
the log end cant position can be achieved by extending the clamps
independently to the designated cant location. However, the
spindle housing as disclosed in the parent application is also
capable of lateral positioning and in such case, both clamps 38'
would simply be extended to a designated position at which the
cant poqition is previously located by adjustment of the spindles.
13~372
It can happen that the desired rotative position for the log
will place the pinchers 110 in line with the path of the clamps
38'. In this event, the computer will simply rotate the log an
additional 90, the log will be transferred to clamps 38', and
clamps ~8' which is designed to rotate the log in 90 increments,
will simply be instructed to readjust the rotative position back
to the desired selected rotative position.
Figs. lla, llb and llc illustrate a further alternative to
the log transfer concept. The support for spindle housing 62
~e.g. sled 66) is designed to carry a transfer clamp arm 114.
When spindle 16'' (which is structured and operates exactly like
spindle 16 of Figs. 3 - 8) has completed its rotation and
repositioning of the log 18, clamp 114 is moved against the log
(arrow 116) to secure the position of the log while spindle 16 "
is retracted (Fig. llb). Clamp 38'' is then moved into the desired
center position as indicated by arrow 115.
Returning to the embodiment of Figs. 3 - 8, the qeneral
arrangement and operations have been described but a number of
details have been skipped over. Logs 18 that are conveyed to the
scanning apparatus 14 are generally not the same length and thus
it is desirable that both the scanning apparatus scan spindles
16 and carriage end clamps 38 adjust to different log lengths.
The task of adjustment is made easier by arranging for the logs to
13
13C~937Z
be conveyed on conveyor 10 with one end of the logs in alignment.
On that end, the spindle support is stationary (although the
spindle is movable relative to the support for engaging and
releasing a log). The spindle support at the opposite end, which
also carries one set oE the centering V's 22, 24, (and clamp 114
where applicable) is movable as illustrated in Fig. 4.
The scanning apparatus 14 includes a frame 60 comprised of
sturdy steel beams that extends over, under and along the sides
of the spindle mechanism. The spindle housing 62 at the adjustable
1end carries the spindle 16 and includes a drive motor for rotatably
driving the spindle. The mechanism for driving the spindle and
extending it relative to the housing is common to scanning spindles
in present use.
15The spindle housing 62 is mounted on a sled 66. The housing
62 is movable on the sled 66 through activation of the hydraulic
cylinder 64 which slides the housing 62 back and forth on rails
68. The sled 66 is mounted on rails 70 that extend just over half
the length of the scanning apparatus. The logs will vary between
8' and 20' in length and to accommodate such variation, the movable
spindle housing must be able to close and open relative to the
fixed spindle housing a distance of about 12'. Because the rough
centering V's 22, 24 are preferably located near the log ends, it
14
13~g372
is necessary to also move the centering V's located adjacent the
movable spindle housing.
As noted from Figs. 3 and 4, the lower V 24 is mounted on
the sled 66. The upper V 22 is mounted on an overhead support 76
that is slidably mounted ~through bearings 82) on the overhead
beams 60a of frame 60. Hydraulic motors ~not shown) connected to
the sled 66 and support 76 move the sled and support back and forth
to the desired distance from the fixed spindle housing as dictated
by the computer 50'. The lengths of the logs are determined by
occlusion scanner 84 that measures the log length, e.g. just prior
to being placed on the stop-and-loader 12. The use of such
scanners for determining log length is common.
In operation, as a log is transferred to the carriage 36,
the computer determines the length of the next log being held by
the stop-and-loader 12 and activates the hydraulic motors to
properly position the upper V support 76 and sled 66. The V's
are opened and the spindle housing 62 at both ends ~as
differentiated from the spindle support, e.g. sled 66) are
retracted by motors 64. The log is rolled onto the lower V's, the
V's are clamped together to rough center the log, and the motors
64 are then activated to drive spindles 16 into the log ends. The
V's are retracted and the log is rotated, scanned and rotatively
13~9372
positioned and adjusted in the vertical and/or lateral directions
as previously described.
The carriageknees 34 have tosimilarly adjustto thedifferent
log lengths. As seen in Figs. 6 and 7, one of the knees 34a is
mounted in a fixed housing 94a, i.e. on the same end as the fixed
spindle housing. The other knee 34b is mounted in a movable
housing 94b on sled 86 that slides on rails 88. Hydraulic motor
90 powers the movement of sled 86 on rails 88 and the motor 90
is controlled by the computer 50' (arrow 92 in Fig. 3). The knees
34a and 34b are slidable relative to their respective housings
94 (arrow 97).
Thus prior to a log being received from the scanning apparatus,
the motor 90 is activated to establish the desired location of
knee 34b. (Note the two extreme positions shown in Fig. 6.) Both
clamps are axially retracted and hydraulic motors 96 are activated
to extend the carriage clamps toward the log, the log being held
in the desired position (rotatively, vertically and/or laterally)
by spindles 16. The clamps cup the spindles as illustrated in Fig.
5 and the knees are extended axially of the log (arrow 96) to
clamp the log ends with the center of the clamps 38 coinciding
with the axis of the spindle 16. ~Or coinciding with the position
determined by the computer for the center cant, in which case
transfer mechanism like that of Figs. 9 and 10 are provided.)
16
13~937Z
Hydraulic motor 96 then retracts the knees to position the log
for sawing, e.g. the position illustrated in Fig. 8.
When positioning the log for sawing, the knees 34 (activated
by motor~ 96) are independently controlled by the computer. The
computer will have determined the exact positions that are desired
for the log in order to generate the desired cutting pattern (see
Fig. 2c). The computer knows the location of saw line 40 and
keeps track of the location of the axis 98 relative to the clamps
38. The selected axis through the log, determined by the computer,
coincides with axis 98 through the clamps 38. The scan data
generated by scanners 26 develops the log configuration relative
to the axis of the spindles and thus relative to axis 98. The
computer is thus able to determine the desired position of the
knees 34a and 34b (both skew position and depth of cut) to line up
the projected cuts for the selected saw pattern with the saw line.
The difference as between the apparatus of Fig. 1 and the
apparatus of Fig. 3 is that end grippers 20 of Fig. 1 perform the
function of skew adjustment as well as rotation adjustment. In
Fig. 3, the spindle 16 adjusts the rotative position of the log
and knees 34 adjust for skew. (Again, however, if centering on
the center cant is desired, vertical adjustment will also be
required and both vertical and horizontal skew positioning can
be accomplished by spindles 16 or clamps 38.) The primary objective
17
13~93~Z
is to establish a preferred rotative position as well as skew
position for a log to be processed into lumber.
Whereas the Real shapeTM analysis of the log is preferred,
one could also simply obtain two-dimensional planar profiles of
the log at each of the rotative positions and simply fit lumber
pieces to the planar profiles at the numerous rotative positions
rather than to a three-dimensional model at these positions. Such
simplified fitting to the numerous log positions could provide
the pre-Real shapeTM testing referred to in the introductory
10portion above.
Other variations of mechanism for obtaining skew and rotative
positions for the log will become obvious. One such "other"
variation may be seen in Fig. 9. The selected rotative position
15is oriented 90 to the saw line, i.e. horizontal rather than
vertical. The desired skew position is then established by raising
and/or lowering the two end spindles 16''' relative to an axis
100 through pivotal arm portions 102 of an overhead end dog
conveyor 104. With the log clamped between arms 102, the spindles
2016 "' are retracted and arms 102 are pivoted 90 (arrow 106).
The log 18 is thereby rotatively positioned and skew positioned.
A still further variation would be to employ a conventional
end log carrîage (like 104 but without the pivot 106) and add an
18
13~93'7Z
XY charger similar to that used for transferring logs to the
veneer lathe in Fig. 1 of the parent application.
An advantage of the Fig. 9 embodiment is the opportunity to
saw multiple slabs from the log so as to require only a single
pass through a saw array indicated by saw lines 108. This may
be preferable for smaller sized logs, e.g. under 20" in diameter
whereas the carriage of Fig. 3 is preferable for larger sized logs.
These and other variations are considered to be within the
1 scope of the invention which is specifically defined in the claims
appended hereto.
