U.S. patent application number 16/175714 was filed with the patent office on 2019-02-28 for lug loader.
The applicant listed for this patent is USNR, LLC. Invention is credited to Damon Clinch, Andre LaPierre.
Application Number | 20190062061 16/175714 |
Document ID | / |
Family ID | 50474405 |
Filed Date | 2019-02-28 |
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United States Patent
Application |
20190062061 |
Kind Code |
A1 |
LaPierre; Andre ; et
al. |
February 28, 2019 |
LUG LOADER
Abstract
Embodiments provide methods, systems, and apparatuses for
loading workpieces in a flow direction into the spaced apart lugs
on a lugged conveyor with the workpieces oriented transverse to the
flow direction. The lug loader includes an array of pairs of
endless conveyors configured to convey workpieces toward a lugged
conveyor. The first and second endless conveyors of each pair are
spaced laterally apart across the flow direction and aligned
substantially in the flow direction. The array can form a
continuous or discontinuous transport surface. Some pairs of
endless conveyors in the array may overlap one or more other pairs
of endless conveyors in the array. At least one pair of endless
conveyors in the array may include two or more endless conveyors
that are independently driven at different speeds and/or in
different directions to de-skew a workpiece.
Inventors: |
LaPierre; Andre; (Vancouver,
WA) ; Clinch; Damon; (Vancouver, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
USNR, LLC |
Woodland |
WA |
US |
|
|
Family ID: |
50474405 |
Appl. No.: |
16/175714 |
Filed: |
October 30, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15582567 |
Apr 28, 2017 |
10144590 |
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16175714 |
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14635862 |
Mar 2, 2015 |
9637313 |
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15582567 |
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14055513 |
Oct 16, 2013 |
9022203 |
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14635862 |
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61714690 |
Oct 16, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65G 47/2445 20130101;
B65G 2203/041 20130101; B65G 47/31 20130101; B65G 2811/0626
20130101; B65G 47/244 20130101; B65G 37/00 20130101; B65G 2811/0673
20130101; B65G 15/58 20130101; B65G 2811/0631 20130101; B65G 15/12
20130101; B65G 2201/0282 20130101; B65G 43/08 20130101 |
International
Class: |
B65G 15/58 20060101
B65G015/58; B65G 15/12 20060101 B65G015/12; B65G 37/00 20060101
B65G037/00; B65G 43/08 20060101 B65G043/08; B65G 47/244 20060101
B65G047/244; B65G 47/31 20060101 B65G047/31 |
Claims
1. An apparatus for transporting successive workpieces in a flow
direction, with the workpieces in a generally transverse
orientation, the apparatus comprising: a plurality of conveyor
modules arranged consecutively in the flow direction to form a
continuous workpiece support surface, wherein each of the conveyor
modules includes corresponding first and second endless conveyors
spaced laterally apart across the flow direction and oriented
substantially parallel to the flow direction; a drive system having
a plurality of drives operatively coupled with corresponding ones
of the endless conveyors, wherein the drive system is configured to
drive each of the first and second endless conveyors independently
of one another and independently of the other endless conveyor
modules; and a first transfer positioned to transfer the successive
workpieces to a first one of the conveyor modules disposed at an
upstream end of the plurality of conveyor modules, wherein the
drive system is selectively operable to drive the first and second
endless conveyors to thereby adjust skew angles of the successive
workpieces and gaps between the successive workpieces while
transporting the workpieces in the flow direction on the plurality
of conveyor modules.
2. The apparatus of claim 1, wherein one or more of the conveyor
modules further includes a third endless conveyor spaced laterally
apart from the corresponding first and second endless conveyors
across the flow direction and oriented substantially parallel to
the flow direction.
3. The apparatus of claim 2, wherein at least one of said drives is
operatively coupled with the third endless conveyor, and the drive
system is selectively operable to drive the third endless conveyor
independently of the corresponding first and second endless
conveyors.
4. The apparatus of claim 3, wherein the third endless conveyor is
positioned at a different vertical height than the corresponding
first endless conveyor.
5. The apparatus of claim 2, wherein the third endless conveyor and
the corresponding second endless conveyor are operatively coupled
to a corresponding one of the drives, such that the third endless
conveyor and the corresponding second endless conveyor are driven
synchronously by the drive system.
6. The apparatus of claim 1, wherein the drive system is
selectively operable to drive some or all of the endless conveyors
in a first rotary direction and in an opposite second rotary
direction.
7. The apparatus of claim 1, wherein said plurality of conveyor
modules includes fewer than six of said conveyor modules.
8. The apparatus of claim 7, further comprising a second transfer
positioned to accept the successive workpieces from a last one of
the conveyor modules disposed at a downstream end of the plurality
of conveyor modules.
9. The apparatus of claim 8, wherein the drive system is configured
to drive the endless conveyors to transport the successive
workpieces on the conveyor modules at a generally velocity.
10. A system for transporting successive workpieces in a flow
direction, wherein the workpieces are oriented generally transverse
to the flow direction, the system comprising: a plurality of
conveyor modules arranged consecutively in the flow direction to
form a continuous workpiece support surface, wherein each of the
conveyor modules includes corresponding first and second endless
conveyors spaced laterally apart across the flow direction and
oriented substantially parallel to the flow direction; and a drive
system coupled with the endless conveyors and selectively operable
to drive the first and second endless conveyors of each of the
conveyor modules independently of one another and independently of
the other conveyor modules; a vision camera positioned to detect
the successive workpieces on the plurality of conveyor modules; and
a computer system coupled with the drive system and the vision
camera, the computer system configured to control the drive system
based at least on data from the vision camera to thereby adjust
skew angles of the successive workpieces and gaps between the
successive workpieces while transporting the successive workpieces
along the plurality of conveyor modules.
11. The system of claim 10, wherein the drive system includes a
plurality of drives, each of the drives operatively coupled with a
corresponding one of the first and second endless conveyors.
12. The system of claim 11, wherein some or all of the conveyor
modules include one or more third endless conveyors spaced apart
from the corresponding first and second endless conveyors across
the flow direction and oriented generally parallel to the flow
direction.
13. The system of claim 12, wherein the drive system further
includes additional drives operatively coupled with corresponding
ones of the third endless conveyors, the additional drives operable
to drive the third endless conveyors independently of the
corresponding first or second endless conveyors.
14. The system of claim 12, wherein at least some of the drives are
operatively coupled with a corresponding one of the second endless
conveyors and a corresponding one of the third endless conveyors,
such that some or all of the third endless conveyors are driven
synchronously with the corresponding second endless conveyors.
15. The system of claim 12, wherein the third endless conveyors are
disposed at a different vertical height than the first endless
conveyors, such that the first and second endless conveyors are
collectively operable to support workpieces of a first length and
the first and third endless conveyors are collectively operable to
support workpieces of a second length.
16. The system of claim 11, wherein the drives include variable
frequency drives.
17. The system of claim 11, wherein the drives include induction
motors.
18. The system of claim 11, wherein the drive system is selectively
operable to drive the first and second endless conveyors in a first
rotary direction and in an opposite second rotary direction.
19. The system of claim 11, wherein the plurality of conveyor
modules includes fewer than six of said conveyor modules.
20. The system of claim 19, wherein a first one of the conveyor
modules is positioned to accept the successive workpieces from a
first transfer upstream of the conveyor modules and a last one of
the conveyor modules is positioned to transfer the successive
workpieces to a second transfer downstream of the conveyor modules.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
Ser. No. 15/582,567 filed Apr. 28, 2017, titled "LUG LOADER," which
is a continuation of U.S. patent application Ser. No. 14/635,862,
filed Mar. 2, 2015, titled "LUG LOADER, issued as U.S. Pat. No.
9,637,313, which is a continuation of U.S. patent application Ser.
No. 14/055,513, filed Oct. 16, 2013, titled "LUG LOADER," issued as
U.S. Pat. No. 9,022,203, which claims priority to U.S. Provisional
Patent Application No. 61/714,690, filed Oct. 16, 2012, titled "LUG
LOADER," the entire disclosures of which are hereby incorporated by
reference.
TECHNICAL FIELD
[0002] Embodiments herein relate to the field of lumber processing,
and, more specifically, to methods, systems, and apparatuses for
loading workpieces onto a lugged conveyor.
BACKGROUND
[0003] Conventional lug loaders or singulators (hereinafter
collectively referred to as either lug loaders or singulators) have
been found to be inadequate at higher feed speeds. They are also
limited in their ability to both singulate and allocate lumber.
When lumber is of varying widths and varying in thickness, or
bowed, as may be predominant in curve sawing mills, cupped or
crooked, and/or skewed on the transfer, it becomes increasingly
difficult to handle the lumber at desirable higher speeds.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Embodiments will be readily understood by the following
detailed description in conjunction with the accompanying drawings.
Embodiments are illustrated by way of example and not by way of
limitation in the figures of the accompanying drawings.
[0005] FIG. 1 illustrates a side elevation view of a prior virtual
lug loader shown in an elongated view having component views in
FIGS. 1A, 1B and 1C intended to be viewed side-by-side in
sequence;
[0006] FIG. 2 is a plan view of the virtual lug loader of FIG. 1
shown in an elongated view having component views in FIGS. 2A, 2B
and 2C intended to be viewed side-by-side in sequence;
[0007] FIG. 3 illustrates the lug loader of FIG. 2 showing,
diagrammatically, sensors and controls;
[0008] FIGS. 4A-C illustrate a present embodiment of a lug loader
and control system; and
[0009] FIG. 5 illustrates another present embodiment of a lug
loader, all in accordance with various embodiments.
DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS
[0010] In the following detailed description, reference is made to
the accompanying drawings which form a part hereof, and in which
are shown by way of illustration embodiments that may be practiced.
It is to be understood that other embodiments may be utilized and
structural or logical changes may be made without departing from
the scope. Therefore, the following detailed description is not to
be taken in a limiting sense, and the scope of embodiments is
defined by the appended claims and their equivalents.
[0011] Various operations may be described as multiple discrete
operations in turn, in a manner that may be helpful in
understanding embodiments; however, the order of description should
not be construed to imply that these operations are order
dependent.
[0012] The description may use perspective-based descriptions such
as up/down, back/front, and top/bottom. Such descriptions are
merely used to facilitate the discussion and are not intended to
restrict the application of disclosed embodiments.
[0013] The terms "coupled" and "connected," along with their
derivatives, may be used. It should be understood that these terms
are not intended as synonyms for each other. Rather, in particular
embodiments, "connected" may be used to indicate that two or more
elements are in direct physical or electrical contact with each
other. "Coupled" may mean that two or more elements are in direct
physical or electrical contact. However, "coupled" may also mean
that two or more elements are not in direct contact with each
other, but yet still cooperate or interact with each other.
[0014] For the purposes of the description, a phrase in the form
"A/B" or in the form "A and/or B" means (A), (B), or (A and B). For
the purposes of the description, a phrase in the form "at least one
of A, B, and C" means (A), (B), (C), (A and B), (A and C), (B and
C), or (A, B and C). For the purposes of the description, a phrase
in the form "(A)B" means (B) or (AB) that is, A is an optional
element.
[0015] The description may use the terms "embodiment" or
"embodiments," which may each refer to one or more of the same or
different embodiments. Furthermore, the terms "comprising,"
"including," "having," and the like, as used with respect to
embodiments, are synonymous.
[0016] In various embodiments, methods, apparatuses, and systems
for loading a lugged conveyor are provided. In exemplary
embodiments, a computing device may be endowed with one or more
components of the disclosed apparatuses and/or systems and may be
employed to perform one or more methods as disclosed herein.
[0017] Examples of virtual lug loaders are disclosed in U.S. Pat.
Nos. 7,578,382 and 7,938,247, both of which are owned by the
assignee of the present application, which is directed to a lug
loader. The disclosures of the patents are substantially reproduced
below for ease of reference.
[0018] Embodiments herein provide methods, systems, and apparatuses
for the singulation or allocation of lumber into lug spaces on a
lugged transfer, or other lumber conveying device.
[0019] Some embodiments provide a system for collecting,
singulating, straightening, allocating and consistently spacing,
rough sawn lumber or planed finished lumber, or sticks of varying
widths, thickness and lengths into consecutive spaced-apart lugs,
or allocated spacings onto a transfer, or lugged transfer, or to a
stick placing device, at high speeds.
[0020] The present disclosure relates to a transfer system. The
transfer system makes use of conveyors such as chains or belts to
move lumber pieces downstream while oriented traversely across the
flow path. The lumber pieces enter the virtual lug loading system
according to the present invention moving transversely. The lumber
pieces may enter as a tightly spaced sheet or mat of pieces with no
gaps, or the lumber pieces may be randomly spaced and oriented.
[0021] Within the system pairs of transfers create consistent gaps
between individual lumber pieces. The transfers within a pair may
be driven individually or ganged together. In one embodiment
individual transfers or pairs of transfers are selectively and
independently actuable to vary their speeds so that the gaps may be
created and/or workpieces may be de-skewed.
[0022] The transfers may create and maintain gapping, that is the
spacing between lumber pieces, and allow a surge capacity. Being
individually driven, the transfers also provide for skew correction
should the lumber pieces arrive skewed or skew during a transition
from one transfer to another. These transfers gap and straighten
the pieces as required so that one piece is positioned into each
lug space on downstream lugged transfer chains. Thus, individually
driven belts provide skew correction to correct the orientation of
skewed lumber pieces on the infeed to the lugged transfer being
loaded. Keeping the lumber pieces straight, that is oriented
traversely across the flow path on the infeed, helps deal the
lumber pieces into the lug spaces.
[0023] Dealing the boards directly into lug spaces without a
mechanical lug loader simplifies the loading of the lug spaces in
the lugged transfer as compared to the prior art. It improves
operator access, and reduces the amount of mechanical components
requiring maintenance.
[0024] In one aspect of the present invention, servo controlled
decks singulate the lumber pieces and position them directly into a
lugged chain.
[0025] In summary, a lug loader as described herein may be operable
for loading workpieces in a flow direction into the spaced apart
lugs on a lugged conveyor, wherein the workpieces are transversely
oriented relative to the flow direction. The lug loader includes an
array of pairs of endless conveyors for conveying the workpieces
downstream, wherein each pair of endless conveyors in the array
include two or more endless conveyors spaced laterally apart across
the flow direction. The array forms a continuous or discontinuous
upper surface in the flow direction for supporting the workpieces
translating downstream in the flow direction. Optionally, each pair
of endless conveyors in the array may overlap adjacent pairs of
endless conveyors in the array. At least one pair of endless
conveyors in the array includes independently actuable first and
second drives independently driving their corresponding first and
second endless conveyors.
[0026] Advantageously, at least some of the endless conveyors of a
pair or pairs of conveyors are independently actuable so as to
correctly orient skewed workpieces anywhere along the transfer
system. The pairs of endless conveyors may translate the workpieces
in the flow direction at relatively similar downstream velocities
between an upstream end and a downstream end of the lug loader.
[0027] The independently actuable pairs of endless conveyors may
each have corresponding selectively actuable drives so that each of
those pairs of endless conveyors is asymmetrically actuable to
drive one endless conveyor ahead of another endless conveyor to
correct skew of a workpiece on any one of those endless
conveyors.
[0028] The adjacent pairs of endless conveyors in the array may
overlap at adjacent ends thereof by one endless conveyor of the
adjacent pairs being inset laterally across the flow direction
relative to a corresponding second endless conveyor of the adjacent
pairs.
[0029] The present disclosure also is intended to include within
its ambit a method of virtual lug loading corresponding
substantially to the use of the above described apparatus.
[0030] As seen in FIGS. 1-3, wherein similar characters of
reference denote corresponding parts in each view, the Virtual Lug
Loader disclosed in U.S. Pat. Nos. 7,578,382 and 7,938,247 includes
a gapping section 10 immediately upstream, relative to a direction
of flow A, of lug loading section 12. Workpieces 14 arrive in
direction A so as to form a mat or blanket 16 of workpieces 14 on
infeed transfer 18. Workpieces 14 arriving at the upstream end of
infeed transfer 18 may be fed from, for example, a tilt hoist, a
landing table, an unscrambler, or other wood handling
machinery.
[0031] Mat 16 is formed on infeed transfer 18 as the workpieces are
slowed on transfer belts at the downstream end of infeed transfer
18, workpieces 14 are urged onto the upstream ends 22a of a first
pair of belts 22 for progressively faster translation of each
workpiece 14 in direction A as the workpieces are transferred from
the downstream end of infeed transfer 18 onto sequentially and
progressively faster successive pairs of belts 22, 24, 26, 28, and
30 within gapping section 10. Gapping section 10 may,
alternatively, may be thought of as a lumber separation zone. Thus,
a workpiece 14 having a velocity Vo in direction A on infeed
transfer 18, will, once handed off to the first pair of belts 22,
have a downstream velocity V1, and then sequentially increasing
velocities V2, V3, V4, V5 thereby sequentially increasing the
separation between individual work pieces 14 by reason of the
progressive acceleration of the boards between pairs of belts.
[0032] Advantageously, the separation between individual workpieces
14 is increased as the length of the gaps, distance G between
adjacent workpieces is increased, for example to approximately one
hundred twenty-five per cent of the length of each lug space,
distance L, between lugs 32a of lugged outfeed chains 32. It is
understood that, although five pairs of belts 22-30 are
illustrated, it is not intended to limit the present invention to
five pairs of belts in gapping section 10 as more or fewer pairs of
belts will suffice so long as sequential workpieces 14 are
separated in direction A so that the gap distance G is at least
equal to lug space distance L.
[0033] The pairs of belts 22, 24, 26, 28 and 30 in gapping section
10 may each be driven by variable frequency drives or induction
motors 34 along with associated gear heads. In the illustrated
example, not intended to be limiting, each of the five speed-up
zones corresponding to the five belt pairs are approximately
sixteen inches long so that the length in the downstream direction
of gapping section 10 is approximately six foot, eight inches.
[0034] In some embodiments, lug loading section 12 is immediately
downstream, and cooperates with, the downstream end of gapping
section 10 so that workpieces 14 are smoothly handed off from belts
30, being the downstream most pair of belts in gapping section 10,
to the first pair of control zone belts 36 located immediately
downstream of the interface between gapping section 10 and lug
loading section 12. Lug loading section 12 is a workpiece control
zone wherein skew may be corrected such as the skew of a workpiece
14' illustrated in dotted outline on control zone belts 38. Skew
correction is accomplished by each belt in each pair of control
zone belts 36, 38, 40, 42, 44, and 46 being able and adapted to
selectively operate at different speeds. In order to correct skew,
for example a skew angle alpha (a) of a skewed workpiece 14 the two
belts 38, and subsequent downstream belts as need be, are driven at
different speeds relative to one another as board 14' passes over
the belts, so that the lagging end of the board catches up with the
advanced end of the board until the board is correctly positioned
perpendicularly across the direction of flow A.
[0035] Apart from operating to correct the skew of workpieces
translating downstream in direction A, the independently actuable
control zone belts in the belt pairs of lug loading section 12
also, in addition to those belts in gapping section 10, operate to
selectively space the boards apart and synchronize the boards with
upcoming lugs 32a as the lugged outfeed chains 32 rotate in
direction C. Thus the control zone belts are driven by a motion
controller (not shown) to accelerate or decelerate pairs of belts
36, 48, 40, 42, 44 and 46 to simultaneously accelerate or
decelerate both belts in individual pairs of belts so as to
accelerate or decelerate a workpiece which has been corrected for a
skew. This is done to synchronize and match the placement of a
particular workpiece into, for example, the middle of a
corresponding lug space as the workpiece exits the downstream end
of lug loading section 12. Thus as may be seen, the acceleration or
deceleration of the sequence of workpieces 14 being translated
downstream over the sequential array of pairs of belts 38, 40, 42,
44 and 46, are selectively motion controlled so as to place a
workpiece 14 entering onto the upstream end of the lugged outfeed
chains 32 preferably into for example the middle of a corresponding
lug space or otherwise exiting off the downstream end of belts 46
just after a pair of lugs 32a rotate to the vertical as chains 32
rotate endlessly around sprockets 48.
[0036] In the illustrated embodiment of FIGS. 1-3, not intended to
be limiting, lug loading section 12 has six control zone belt pairs
may be thought of as six belt modules each approximately sixteen
inches long in the downstream direction for a total downstream
length of eight feet. In one preferred embodiment, the motors 50
which selectively individually drive each belt in each belt module,
may be servo motors having corresponding gear heads.
[0037] It is understood that sensors 52 such as seen in FIG. 3 and
known in the prior art, and as would be known to one skilled in the
art, would be provided to detect the position of individual boards
and that the information from the sensors is processed by a digital
processor 54 cooperating with the sensors and that the digital
processors also cooperates with a programmable logic controller
(PLC) 56 via network 58 which in turn cooperates with the motors
for selectively driving the belts 22, 24, 26, 28 and 30 in gapping
section 10 and belts 36, 38, 40, 42, 44 and 46 in lug loading
section 12.
[0038] FIGS. 4A-C and 5 illustrate present embodiments of a lug
loader and control system. In the embodiment of FIGS. 4-5, to
facilitate the description, components substantially similar to
those components identified in FIGS. 1-3 are identified by the same
reference characters. Unless otherwise indicated, such components
may function in the same or similar manner as described above.
[0039] In contrast to the virtual lug loader disclosed in U.S. Pat.
Nos. 7,578,382 and 7,938,247, the present embodiment of a lug
loader system includes a combined gapping and de-skewing section
100 between infeed transfer 18 and the lugged conveyor (FIG. 4A).
Again, successive workpieces 14 are urged from infeed transfer 18
onto the upstream ends 22a of a first pair of belts 22. First pair
of belts 22 may be driven at a speed that is greater than the speed
of infeed transfer 18. Unlike the above-described embodiment, gaps
are created between the workpieces 14 by driving the successive
pairs of belts 22, 24, 26, 28, 30, 36, 38, 40, 42, 44, and 46
within section 100 at generally the same or similar speeds. Thus, a
workpiece 14 having a velocity Vo in direction A on infeed transfer
18, will, once handed off to the first pair of belts 22, have a
downstream velocity V1, and will continue to have approximately the
same velocity while traveling on successive pairs of belts except
while being de-skewed, if necessary (see e.g., FIGS. 4B and 5).
[0040] It is understood that, although eleven pairs of belts 22-46
are illustrated, it is not intended to limit the present invention
to eleven pairs of belts in section 100 as more or fewer pairs of
belts will suffice. In addition, although the present description
refers to "pairs" of belts, it is to be understood that a "pair"
may include two, three, four, five, or more than five belts
arranged across the direction of workpiece flow. For example, one
or more of the pairs of belts 22, 24, 26, 28, 36, 38, 40, 42, 44,
and 46 may include five belts, allowing for use of the lug loader
to load longer lengths of lumber onto a lugged conveyor. Thus, a
relatively long workpiece that is skewed may have a first end that
is in contact with a belt of one pair and an opposite end that is
in contact with a belt of another pair (see e.g., FIG. 5).
[0041] Optionally, one or more of the belts of a pair may be set at
different vertical heights. For example, a pair of belts arrayed
across the direction of flow may include a first belt at a first
side of the conveyor that is positioned at a first vertical
distance D1 from an underlying support surface (e.g., a floor), a
second belt that is positioned at a second vertical distance D1, a
third belt that is positioned at a third vertical distance D3, a
fourth belt that is positioned at a fourth vertical distance D4,
and a fifth belt that is at the opposite side of the conveyor and
is positioned at a fifth vertical distance D5. The vertical heights
may increase incrementally from D1 to D5 (e.g., by 0.25 inches). As
a result, workpieces conveyed along this pair of belts may be in
contact with only two belts. Thus, a workpiece of relatively short
length may be in contact with the first belt and the second belt, a
workpiece of intermediate length may be in contact with the first
belt and the third belt, and a relatively long workpiece may be in
contact with the first belt and the fifth belt. In some embodiment,
multiple pairs of belts may be arranged in such a manner.
[0042] The pairs of belts 22, 24, 26, 28, 30, 36, 38, 40, 42, 44,
and 46 in section 100 may each be driven by variable frequency
drives or induction motors 34 along with associated gear heads.
Skew may be corrected along the length of section 100, such as the
skew of a workpiece 14' illustrated in dotted outline in FIG. 5.
FIG. 5 shows a relatively long workpiece skewed such that a first
end of the workpiece is engaging a first belt of the pair of belts
38 and a second opposite end of the workpiece is engaging a fifth
belt of the pair of belts 30. Skew correction is accomplished by
selectively operating the two belts in contact with the workpiece
to operate at different speeds. Typically, this is done by
operating one of the two belts to rotate at a greater speed than
the other of the two belts. However, skew correction may
alternatively be done by operating one of the two belts to rotate
in the direction of flow and operating the other of the two belts
to rotate in the opposite direction. In any case, one or more of
the belts in at least some of the pairs of belts 22, 24, 26, 28,
30, 36, 38, 40, 42, 44, and 46 may be selectively operated at
different speeds in order to correct skew. For example, to correct
a skew angle alpha (a) of a skewed workpiece 14, the first belt of
the pair of belts 38 and the fifth belt of the pair of belts 30
(and subsequent downstream belts as need be) are driven at
different speeds or in different directions relative to one another
as board 14' passes over the belts. The belts may be selectively
driven to apply relatively greater speed to the lagging end of the
board, or to slow the advanced end of the board, until the board is
correctly positioned perpendicularly across the direction of flow
A.
[0043] Apart from operating to correct the skew of workpieces
translating downstream in direction A, the belt pairs of section
100 also operate to selectively space the boards apart and
synchronize the boards with upcoming lugs 32a as the lugged outfeed
chains 32 rotate in direction C. Thus some or all of the belts may
be driven by a motion controller (not shown) to simultaneously
accelerate or decelerate the belts within individual pairs of belts
so as to accelerate or decelerate a workpiece which has been
corrected for a skew. This is done to synchronize and match the
placement of a particular workpiece into, for example, the middle
of a corresponding lug space as the workpiece exits the downstream
end of section 100. Thus as may be seen, the acceleration or
deceleration of the sequence of workpieces 14 being translated
downstream over the sequential array of pairs of belts are
selectively motion controlled so as to place a workpiece 14
entering onto the upstream end of the lugged outfeed chains 32
preferably into for example the middle of a corresponding lug space
or otherwise exiting off the downstream end of belts 46 just after
a pair of lugs 32a rotate to the vertical as chains 32 rotate
endlessly around sprockets 48.
[0044] In the illustrated embodiment of FIGS. 4-5, not intended to
be limiting, section 100 has eleven belt pairs. However, other
embodiments may have six, seven, eight, nine, ten, twelve, more
than twelve, or fewer than six belt pairs. In one preferred
embodiment, motors 50 may selectively individually drive one or
more of the belts in a pair. Optionally, motors 50 may be servo
motors having corresponding gear heads.
[0045] In contrast to the virtual lug loader disclosed in U.S. Pat.
Nos. 7,578,382 and 7,938,247, which disclosed sensors 52 (FIG. 3)
to detect the position of individual boards, the present embodiment
includes a vision camera 152 mounted above the lug loader apparatus
such that the field of view encompasses most or all of the pairs of
belts (FIGS. 4B, 4C). The vision camera 152 may be coupled to a
computer system 154. Computer system 154 may in turn be operatively
coupled to motors 50, programmable logic controller 156, a driver
of infeed 18, and/or a driver of the lugged conveyor. Together,
vision camera 152 and computer system 154 may comprise a vision
based lumber flow management system that optimizes lumber flow
during processing. Such a system may reduce the expense of
installing and maintaining multiple sensors. In addition, the
overhead vision camera may provide a clear view of the workpieces
and be less susceptible to dust and moisture and reducing the need
for frequent maintenance (e.g., lens and reflector cleaning).
[0046] The vision based system operates by creating a virtual array
of presence detection points along the lug loader. As workpieces
travel through the detection area, the system recognizes the
presence or absence of workpieces as well as width, length, and
skew of the workpieces. Based on this and other data, the computer
system 154 may send commands to programmable logic controller (PLC)
156 which in turn cooperates with the motors 50 for selectively
driving the belts 22, 24, 26, 28, 30, 36, 38, 40, 42, 44 and 46 in
section 100. In this manner, the computer system 154 may
selectively drive the belts to de-skew workpieces and create
desired gaps between them. Optionally, computer system 154 may also
send commands to one or more drivers of infeed 18 and/or the lugged
chain conveyor based on this and other data (e.g., to speed or slow
infeed 18 and/or the lugged chain conveyor).
[0047] While the above description refers to loading a lugged chain
conveyor, it is to be understood that a lug loader as described
herein may alternatively be used to de-skew and/or create gaps
between workpieces upstream or downstream of any other apparatus.
Examples include, but are not limited to, a sorter, a ducker, a
translineator, a cutting device, and a grading station.
[0048] Although certain embodiments have been illustrated and
described herein, it will be appreciated by those of ordinary skill
in the art that a wide variety of alternate and/or equivalent
embodiments or implementations calculated to achieve the same
purposes may be substituted for the embodiments shown and described
without departing from the scope. Those with skill in the art will
readily appreciate that embodiments may be implemented in a very
wide variety of ways. This application is intended to cover any
adaptations or variations of the embodiments discussed herein.
Therefore, it is manifestly intended that embodiments be limited
only by the claims and the equivalents thereof.
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