Note: Descriptions are shown in the official language in which they were submitted.
D6
LUMBER SORTER AND MæTHOD
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to lumber
handling and sorting equipment, and more particularly to
lumber edging picker conveyors.
2. Description o the Prior Art
In a lumber mill, rough boards which are cut from
a log ar sent through an "edger," where bark and board
edges of uneven outline are removed to leave a board of
substantially rectangular cross section. The edger
typically has two or more spaced apart, side-by-side
circular saws, through which a wide, untrimmed board or
lumber slab is conveyed lengthwise. In addition to
trimming off rough outside edges, the edger often performs
longitudinal cuts on the boards, thereby dividing each
board into two or more narrower boards.
During this trimming or "edging" operation, the
narrow, rough strips or "edgings" are removed from the
lumber and must somehow be isolated from the boards
downstream of the edger saws. Optimum efficiency usually
results if, on leaving the edger, the edgings are
immediately separated out from the flow of boards,
enabling the boards to be further processed without
encumbrance by the edgings. Once the edgings are
separated out~ they are chipped, burned, or otherwise
treated. The equipment for performing this separating
function is typically referred to as an edging picker
outfeed conveyor.
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Conventional outfeed conveyors are disclosed in
U.S. Patent Nos. 3,139,125 and 3,017,909 and are marketed
by Schurman Machine Works, Inc., and Portland Iron Works.
The principle of operation of the conveyors disclosed in
these patents and of the Schurman and Portland conveyors
is basically the same. The outfeed conveyor has a first
fîxed "fence" which is aligned with a first fixed edger
saw, which cuts off one rough edging. The outfeed
conveyor also has a movable fence, which is aligned with
and moves with a second laterally movable saw or a third
saw if the lumber slab is to be cut into two narrower
boards. In any event the movable fence is typically
aligned with the saw that cuts off the second rough edge.
As the lumber moves through the edger saws, the waste
edging from tAe first saw is diverted by the first fixed
fence to one side of the outfeed conveyor. The edging cut
by the second or third saw is diverted by the movable
fence to the other side of the outfeed conveyor. The
finished lumber, cut to width, moves over the outfeed
conveyor hetween the fences.
Variations of these basic prior art edging picker
outfeed conveyors are disclosed in the following U.S.
patents: No. 1,724,042 uses a fixed shear strip with a
wedge-shaped downstream end portion to divert edgings
laterally from the edged lumber ~see FigO B); No.
2,468,036 uses rollers with one set of enlarged ends
aligned with the saw blade to cause a slab cut from a log
to lie flat as it is diverted sideways after being
separated from the log; No. 3/687~269 uses a conventional
edging picker along with sweep plates or fingers; and No.
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3,732,765 uses sweep fingers to separate and divert cut
lumber in desired directions on an outfeed conveyor.
A second type of conventional edging picker
outfeed conveyor is disclosed in the U.S. Patent No.
3,225,8000 The apparatus disclosed in ~his patent uses a
pair of outfeed conveyor belts downstream of the edger,
with both belts being laterally displaceable so that one
belt is always aligned between the fixed and one movable
saw, while the other belt is always aligned between the
one movable saw and a second movable saw. The belts are
driven and appear to be the principal outfeed conveyor
means for the edged lumber. Although it is unclear from
the patent, it appears that the edgings drop to opposite
sides of the two beltsO
All of the above-described systems are relatively
complex in design and therefore involve a subs~antial
capital investment to purchase. Because of this
complexity~ they can also be difficult and therefore
expensive to maintain. In normal operation, wearing oE
the components can result in inaccuracy which can
dramatically affect the performance of the system because
precise adjustment of the various components is often
essential to ensure proper operation. Another problem
with many prior art designs, which is particularly
noticeable with respect to the system disclosed in U.S.
Patent No. 3,2~5,800, is that the operator must wait until
lumber i5 downstream of the edging picker conveyor before
resetting the position of the edger saws. If this is not
done~ there is a good chance oE losing lumber off of the
belts as they shift in a lateral direction. Since the
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saws must often be reset after each board has passed
through, the necessi~y of having to wait for the prior
board to clear the conveyor dramatically reduces the
output of the edger.
Hence, it is a primary object of the present
invention to provide an improved lumber sorter which
effectively and reliably overcomes the aforementioned
limitations and drawbacks of the prior art proposals.
More specifically, the present inven~ion has as its
objects one or more of the following, taken individually
or in combination:
~ 1) The provision of an edging picker conveyor
which can operate at higher speeds by permitting
transverse adjustment of the edger saws while the board
which has just passed through the saws is still on the
edging picker conveyor
~ 2) To develop an edgi.ng picker conveyor in
which the settings and adjustments need not be as precise
as with the prior art proposals, thereby simplifying
operation and eliminating the re~uirement of costly and
complicated control mechanisms;
(3) To provide a lumber sorter which is simple
in construction and therefore is relatively inexpensive to
purchase and is reliable, requiring a minimum of
maintenance; and
(4) The development of an edging picker conveyor
whi.ch is narrower than prior art designs and is adapted to
eject edgings downwardly rather than laterally, thereby
facilitating the use of a greater number of picker
conveyors in any given space.
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SUMMARY OF THE INVENTION
This invention responds to the problems pre-
sented in the prior art by providing a lumber sorter
which is adapted to sort laterally aligned pieces of
lumber. Thus, while the invention is normally used as
an edging picker conveyor to separate edged boards from
adjacent edgings, the invention is applicable to resaw
operations or the like where a plurality of boards have
been cut from a single slab of lumber, the boards being
aligned and being directed endwise into the sorter. The
present invention provides a lumber edging picker con-
veyor adapted to receive boards and adjacent edgings
from a lumber edger and having a plurality o edger saws
wherein the conveyor includes:
(1) means for driving the boards along a
Eirst path of travel, while driving the
edgings along a second path of travel, the
second path being vertically divergent with
respect to the first path;
(2~ laterally extending support means Eor
receiving the hoards from the driving means
and for supporting the boards in the first
path of travel; and
(3) means for transversely displacing at
least a portion of the driving means in res-
ponse to transverse displacement of at least
one of the edger saws, where the transverse
displacement means includes time delay means
for delaying the transverse displacement of
the driving means in response to transverse
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displacement of at least one of the edger
s ~ws .
The invention may alternatively be defined as
a lumber edging picker conveyor which includes the
following componentsO
(1) Lumber drive means for receiving boards
and adjacent edgings from a lumber edger and
for driving the boards and the edgings along a
predetermined path; and
(2) Inclined ramp Ineans for conveying only
the boards along an upwardly inclined path
while the boards and the edgings are being
driven by the lumber d-ive means, so that the
boards will be progressively displaced verti-
cally with respect to the edgings. The con-
veyor is adapted to receive lumber from an
edger having a first, a second and a third
saw, the second and third saws being trans-
versely displaceable to saw boards of various
widths. The inclined ramp means includes a
first upwardly inclined ramp member disposed
to receive boards cut between the first and
second saws, and a second upwardly inclined
ramp member disposed to received boards but
between the second and third saws, the second
ramp member including means for transverse
displacement thereof to accommodate for trans-
verse displacement of the second and third
saws, the first and second ramp members being
no wider than the cut boards thereadapted to
receive. According to one aspect of the
invention, each of the ramp members includes a
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plurality of radially-aligned, freely rotata-
ble rollers :Eor receiving boards and permit-
ting them to glide upwardly toward the support
means. According to a further aspect of the
invention, the means for transversely displa-
cing the second ramp member may include time
delay means for delaying the transverse dis-
placement of the second ramp member after
displacement of the second and third saws.
Yet another way to define the invention is as
an edging picker conveyor for separating edgings from
edge boards which includes the following:
(1) First conveyor means downstream of the
saws for receiving and conveying the edgings
and the edged boards endwise;
(2) Second conveyor means downstream of and
in line with the first conveyor means but
spaced therefrom to define a gap therebetween,
the second conveyor means being disposed at a
different level than the first conveyor means,
the first conveyor means being driven and
operable to convey the edged boards and
edgings endwise downstream into and beyond the
gap; and
(3) Ramp means ~ridging the gap so that the
first conveyor means can convey edged boards
endwise over the ramp means and onto the
second conveyor means, the ramp means inclu-
ding separate ramp elements defining the
lateral limits of the ramp means, at least one
of the separate ramp elements being selective-
ly moveable transversely to determine which of
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the cut edgings and boards will be conveyed by
the first conveyor means onto the ramp rneans.
According to one aspect of the invention, the
conveyor means may include lumber hold-down
means for maintaining a desired longitudinal
aliqnment of the boards after they leave the
saws.
The invention may alternatively be defined as
an edging picker conveyor for separating at least one
edging from an adjacent board including the following
components:
(1) First dr;vsn conveyor means extending
downstream of the saw means for receiving and
conveying endwise downstream said edging and
board;
(2) Second driven conveyor means downstream
of and in line with the first conveyor means
but spaced thereErom to define a gap there-
between, the second conveyor means being
disposed at a level above the first conveyor
means, the eirst conveyor means including
hold-down means operable to maintain the edged
board and edging endwise in alignment with the
second conveyor means as they are conveyed
downstream by the first conveyor means into
and beyond the gap; and
(3) Inclined ramp means bridging the gap and
inclined in a direction from the first convey-
or means to the second conveyor means, the
ramp means being longitudinally aligned with
the edged board and havin~ an effective width
less than the ~irst conveyor means, such that
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the first conveyor means drives the edged
board up the ramp means and onto the second
conveyor means, whereas the first conveyor
means drives the edging along a transversely
straight path parallel to and laterally offset
from the ramp means and at a level below khe
second conveyor means.
8RIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and
objects other than those set forth above will become
apparent when consideration is given the following
detailed description thereof. Such description makes
reference to the annexed drawi.ngs wherein:
FIGURE 1 is a plan view of one embodiment of
the presen~ invention depicting the edger saws and
lifter arms in both an initial and an adjusted position
(the latter being in pha~tom);
FIGURE 2 is a side elevation sectional view
taken along line 2--2 of figure 1 depicting a board and
its edgings being driven through the edging picker con-
veyor of Figure l;
FIGURE 3 is an end elevation sectional view
taken along line 3--3 of Figure 2, also depicting the
liter arms in an initial and an adjusted position (the
latter being in phantom);
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FIGURE 4 is a fragmentary perspective view of the
embodiment of Figures 1-3 depicting the means for
transversely adjusting the position of the lifter arms; and
FIGURE 5 is an enlarged schematic view showing
the adaptability of the lifter arms to receive boards of
variouC widths.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The principles of this invention are particularly
useful when embodied in a lumber edging picker conveyor,
such as that illustrated in Figures 1-5i generally
indicated by the numeral 10. As shown in Figures 1 and 2,
edging picker conveyor 10 is adapted to be positioned
immediately downstream of a lumber edger 12. Edger 12
includes a plurality of axially aligned, circular saws
14a, 14b, and 14c which are mounted to a drive shaft 16.
the drive shaft 16 is driven at a high rate of speed by
conventional means (not shown~O It should be appreciated
that edging picker conveyor 10 may be modified as
described below, to be used with edgers having as few as
two or as many as four or more edger saws.
As indicated in phantom in Figure 1, edger saws
14b and 14c are designed to be transversely adjustable.
The means for providing such adjustability are of
conventional design and therefore have not been depicted
nor will be described herein. The adjustability is
provided in order to adapt the system to cut boards of
different widths. For example, the position of the edger
saws 14a and 14b depicted in solid lines might define a
spacing of four inches so that a two-by-four would be
cut. In fact, with the three edger saws 14a, 14b, and 14c
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in the positions depicted in solid linest edger 12 would
be adapted to saw two two-by~fours from a single slab of
lumber. Wi~h edger saws 14b and 14c shifted to the
positions depicted in phantom, edger 12 would be adapted
to saw a single two-by-six, or a two-by-six and a
two-by-four, ou~ of a single lumber slab. Again this
edger capability i5 well known in the art, ~o will not be
described further.
First and second drive rolls 18 and 19 are
disposed immediately downstream of edger 12, to receive
boards 24 and their adjacent edgings 24', and to drive the
boards and edgings into the edging picker conveyor lO.
Drive rolls 18 and l9 are rotatably mounted to a conveyor
frame 23 and are typically driven off a motor (not shown)
of conventional design, at an equal rate of speed. A
first hold-down roll 26 is positioned above and between
first and second drive rolls 18 and 19 and is permitted to
rest upon but rotate freely with respect to the boards 24
and their edgings 24'. This ensures effective driving of
the boards and edgings, bu~ since first hold-down roll 26
is merely resting upon the lumber and is not vertically
ixed in conveyor frame 23, it can accommoda~e boards of
differing thicknesses~
A third drive roll 20 and a second hold-down roll
28 are provided immediately downstream of first and second
drive rolls 18 and 19 and first hold-down roll 26. Third
drive roll 20 and second hold-down roll 28 continue the
driving of boards 24 and their adjacent edgings 24' and
prevent any deflection or misdirection thereof. Third
drive roll 20 and second hold-down roll 28 are similarly
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rotatably mounted to conveyor frame 23, with the third
drive roll being driven by the same motor that drives
first and second drive rolls 18 and 19. Like first
hold-down roll 26, second hold~down roll 28 merely rests
upon the board and edgings and is not vertically fixed
with respect to conveyor frame 23, thereby accommodating
lumber of di~fering thicknesses.
Fourth and fifth drive rolls 21 and 22 continue
to drive the boards 24 and adjacent edgings 24' and are
knurled to increase friction and minimize the possibility
of lateral deflection of the boards and edgings. Fourth
and fifth drive rolls 21 and 22 are also rotatably mounted
in conveyor frame 23 and are driven by the motor (not
shown) which drives first, second, and third drive rolls
18, 19, and 20. Figure 3 depicts a fifth drive roll drive
wheel 29 which is mounted to drive fifth drive roll 22 via
a drive belt 31. While corresponding drive wheels have
not been shown for first through fourth drive rolls 18-21
in order to simplify the drawings, such drive wheels are
normally provided.
As shown best in Figure 2, upwardly inclined ramp
means 30 are provided for guiding the boards 24, but not
their edgings 24', along an upwardly inclined path of
travel~ In the depicted embodiment ramp means 30 comprise
a pair of side-by-side lifter arms 32 and 32a, to which
are mounted a plurality of freely rotatable rollers 34 and
34a. In some applications, the rollers 34 and 34a may be
deleted, but in order to reduce friction between lifter
arms 32 and 32a and the boards 24, the rollers are
normally included.
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Lifter arms 32 and 32a are mounted to first,
second, and third lifter arm support members 36, 38, and
40 which extend between the two sides of a conveyor roll
case 42.
Bushings 44 and 44a are typica]ly included to
mount lifter arms 32 and 32a to lifter arm support members
36, 38, and 40. Lifter arm 32a is transversely
displaceable, while lifter arm 32 is fixed with respect to
lifter arm support ;nembers 36, 38, and 40. To accommodate
for this difference in function, bushings 44 are provided
with set screws 46, which fix lifter arm 32 with respect
to lifter arm support members 36, 38, and 40. Bushings
44a, on the other hand, are provided with grease fittings
48 to ensure that lifter arsm 32a will be freely movable
along lifter arm support members 36, 38, and 40.
The function of lifter arms 32 and 32a is to
receive the boards 24 from edger 12 and to guide the
boards, but not their adjacent edgings, along an upwardly
inclined path of travel. Thus, the edgings 24' follow a
2n second, initially horizontal, path of travel which becomes
downwardly disposed as the efEects of gravity take hold on
the edgings. Since it is essential that lifter arms 32
and 32a support only the boards 24 and not their edgings
24', the transversely adjustable lifter arm 32a must be
disposed in a position which is directly related to the
position of adjustable edger saws 14b and 14c. Lifter arm
32 is transversely fixed, as is edger saw 14a; so these
components will always be disposed properly. However,
with edger saws 14b and 14c in the position depicted in
solid lines in Figure l, lifter arm 32a must be disposed
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somewhere in the vicinity of the position depicted in
solid lines in Figure 1. With edger saws 14b and 14c
adjusted to the position depicted in phantom in Figure 1,
ramp lifter arm 32a must also be shifted to something
approximating the phantomed position. This will ensure
that lifter arm 32a will be substantially centered between
edger saws 14b and 14c and will properly receive the board
24 cut by those saws.
The coopera~ion of edger saws 14b and 14c and
lifter arm 32a will be described in more detail in the
operation sections of this description, but the structure
of the components providing this cooperation will now be
described.
Electrical circuitry (not shown) actuates a
lifter arm shifting mechanism 30, depicted in Figures 3
and 4, so that any transverse displacement of edger ~aws
14b or 14c will result in a corresponding transverse
shifting of lifter arm 32a. For reasons which will be
evident in the Operation sections of this description, a
time delay is provided between the shifting of edger saws
14b and 14c and that of lifter arm 32a. Once the time
delay has occurred and the circuitry demands a transverse
shifting of lifter arm 32a, switches (not shown) are
activated to send control air to either a two-inch section
52a or a three-inch section 52b of a pneumatic control
cylinder 52, which will cause the control cylinder to
either extend or contract two or three inches. Pneumatic
control cylinder 52 is pivotally connected on one end to a
control cylinder support arm 54 which extends downwardly
from conveyor roll case 42, and on the other end to a
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control cylinder extension arm 56~ The control cylinder
extension arm 56 is rigidly mounted to a control cylinder
shaft 58 which is rotatably mounted to conveyor roll case
42 by bushings 60. Control cylinder shaft 58 is
interconnected with transversely adjustable lifter arm 32a
by a pair of lifter arm extension members 62 and lifter
arm extension links 64, which are pivotally mounted to one
another so that any rotational displacement of control
cylinder shaft 58 will be conveyed through these members
to transversely shift lifter arm 32a across lifter arm
support members 36, 38, and 40.
Upwardly extending fences 65 and 67 are provided
along each lateral edge of edging picker outfeed conveyor
13 to prevent the boards 24 from sliding off of the
conveyor during the picking process. The fence 67 which
is adjacent the drive means for drive rolls 18 22 actually
takes the form of a protective cover for the drive means,
thereby serving two separate functions~
First, second, and third outfeed shaft rolls 66,
68, and 70 are provided immediately downstream of ramp
means 30 to receive the boards 24, but not the edgings
24', and convey the boards along a substantially
horizontal path. Outfeed shaft rolls 66, 68~ and 70 are
rotatably mounted to conveyor roll case 42 and are driven
at a rate of speed which corresponds to that of drive
rolls 18, 19, 20, 21, and 22, but by a separate outfeed
shaft motor (not shown). Each of the outfeed shafts 66,
68, and 70 includes bearings on each end, one of which is
shown for each shaft at 72, 74, and 76, which is driven by
a common chain (not shown) from an outfeed shaft motor
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tnot shown)O In the pre-ferred design at least first
outfeed shaft 66 is knurled, although this is not a
necessary feature~ As shown best in Figure 2, the edgings
24', which are not supported by outfeed sha~t rolls 66,
68, and 70, are permitted to drop downwardly into a bin or
a suitable conveyor (not shown). In order to facilitate
the handling of e~tremely stiff edgings which have not yet
dropped down into the bin or conveyor by the time the
boards and edgings reach the end of edging picker conveyor
10, an edging shear 78 is provided to wedg~ remaining
edgings 24' downwardly away from the boards 24.
Additonal out~eed rolls are typically provided
downstream of outfeed shaft rolls 66, 68, and 70 in order
to continue the conveyance of boards 24 to the next work
station. Only one such additional outfeed roll 80 is
depicted in the figures.
Principle of_Operation
The principle on which the present invention
operates is to drive the boards 24 along a path of travel
which is upwardly inclined with respect to the path of
travel in which the edginys 24' are dxiven. In the
depicted embodiment this feature is provided through the
use of lifter arms 32 and 32a and rollers 34 and 34a. The
edgings 24', which are immedately adjacent the boards 24
as the boards and edgings leave edger 12, are not
supported by lifter arms 32 and 32a and are therefore
permitted to progressively drop, by gravity, with respect
to the boards 24.
Figure 5 schematically depicts the method by
which rollers 34 and 34a support the boards 24 without
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supporting edgings 2~'. This figure, which depicts the
boards, edger saws, and rollers from an endwise direction,
is greatly enlarged compared to the other figures. ~t
position A in Figuxe 5, edger saws 14a and 14b are
disposed to cut a single two-by-four froM a slab of
lumber. Lifter arm 32, whic~ is transversely fixed,
supports rollers 34 in position between edger saws 14a and
14b. Thus, the resulting two-by-four board 24 which is
cut by edger saws 14a and 14b is supported by rollers 34,
while the edgings 24' are not. In the depicted
embodiment, rollers 24 are slightly offset with respect to
the transverse centerline of two-by-four board 24.
However, this does not, in actual operation, affect the
performance of edging picker conveyor 1~; that is, the
configuration of rollers 34 and 34a is such that adequate
support is provided for the boards 24. This capability of
edging picker outfeed conveyor 10 to operate
~atisfactorily as long as the rollers are disposed in a
generally central position under the boards is a real
advantage over some of the prior art designs which require
precise positioning of the components.
During the cutting of a single two-by-four, the
position of lifter ar~ 32a and its rollers 34a is
unimportant as long as rollers 34a are sufficiently
displaced with respect to rollers 34 so that the adjacent
edging 24' will not contact rollers 34a. ~hus, it will
usually be sufficient to transversely shift rollers 34a
two inches rightwardly to the position depicted in phantom
in Figure 5. Howevex, it is preferable to shift rollers
34a an additional three inches to the right of the
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phantomed position, or a total of five inches Erom the
position depicted in solid lines, in order to ensure that
rollers 34a do not obstruct the fall of the adjacent
edging 24'.
Position B in Figure 5 depicts the cutting of a
two-by-six board 24 (although the edgings 24' have not
been depicted for simplication purposes). ~dger saw 14b
is first shifted transversely to the position depicted in
phantom. As the lumber slab is passing through edger 12
and is being cut by edgex saws 14a and 14b, but before
board 24 reaches rollers 34 and 34a, lifter arm 32a and
its rollers 34a are transversely shifted to the position
referred to above (but not depicted), five inches to the
right of the position depicted in solid line. With
rollers 34a thus positioned lifter arm 32 and rollers 34
provide support for the edged two-by-six board 24 but do
not obstruct the fall of the edgings 24'. Again, it may
be sufficient to shift rollers 34a only two inches
rightwardly to the position depicted in phantom, but, for
the reason described above, that is not the preferred
procedure.
Position C of Figure 5 depicts the cutting oE two
two-by-four boards 24 from a single lumber slab. Again,
for simplification, edgings 24' have been deleted. In
other to cut the two two-by-fours, edger saw 14b is
shifted to the position depicted in solid lines in Figure
5, and lifter arm 32a and rollers 34a are subsequently
moved into the position also depicted in solid lines in
Figure 5. Edger saw 14c is positioned also as depicted in
solid lines, so that two two-by-four boards 24 are cut and
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so that lifter ax~s 32 and 32a and rollers 34 and 34a
support each of the boards. Thus, edgings 24' (not shown)
are permitted to drop downwardly due to lack of support as
the boards 24 glide up lifter arms 32 and 32a.
Position D of Figure 5 depicts the cutting of a
two-by-six board and a two-by-four board from a single
lumber slab. In order to perform the cutting operation,
edger saw 14b is shifted to the position depicted in
phantom in Figure 5, as is edger saw 14c. Lifter arm 32a
and rollers 34a axe then shifted to the position depicted
in phantom, thereby providing support for the two-by-four
board, while rollers 34 provide support for the
two-by-six. The edgings 24' (not shown) ar~ permitted to
drop downwardly by gravity as the boards 24 are conveyed
up the incline provided by lifter arms 32 and 32a.
Operation of the Depicted Embodiment
The complete operation of the edging picker
conveyor 10 will now be described, beginning with the
edging operation taking place at edger 12. If a pair of
two-by-four boards are to be cut from a lumber slab being
fed into edger 12, edger saws 14a, 14b, and 14c will be
disposed as depicted in solid lines in Figure 1. It will
be assumed that lifter arms 32 and 32a are already
disposed in the position depicted in solid lines in
Figures 1 and 3, ready to receive the two two-by-four
boards.
Once boards 24 and edgings 24' are cut by edger
saws 14a, 14b, and 14c, the boards and adjacent edgings
will be received by first and second drive rolls 18 and 19
and first hold-down roll 26. The weight of first
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hold-down roll 26 maintains boards 24 and edgings 24' in
contact with drive rolls lB and 19 to prevent slippage.
The boards 24 and edgings 24' are then passed to third
drive roll 20 and second hold-down roll 28 which operate
like drive rolls 18, 19, and first hold-down roll 26 to
continue to convey the boards 24 and edgings 24' in a
generally horizontal path of travel. Third drive roll 20
and second hold-down roll 28 serve the additional purpose
of holding the boards 24 and the edgings 24' in position
to prevent any la~eral or vertical deflection. The boards
24 and the edgings 24' are then directed across fourth and
fifth drive rolls 21 and 22 which are knurled to engage
the boards and edgings to minimize the possibility of any
lateral deflection~ Once the boards 24 begin to glide up
rollers 34 and 34a on lifter arms 32 and 32a, the boards
will typically be lifted out of engagement with fourth and
fifth drive rolls 21 and 22. However, the edgings 24' are
normally maintained in contact ~ith fourth and fifth drive
rolls 21 and 22, as depicted in Figure 3, thereby ensuring
that the edgings will be continuously conveyed in a
downstream direction.
As shown at position C in Figure 5, the two
two-by-four boards 24 are received by rollers 34 and 34a
on lifter arms 32 and 32a, thereby directing the boards
along an upwardly inclined path of travel. No support is
provided to the edings 24', which therefore continue to
pass along a substantially horizontal path of travel as
depicted in phantom in Figure 2. As drive rolls 18-22
continue to convey the boards 24 and the edgings 24' in a
downstream direction, the boards 24 glide up rollers 34
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~Z~6~9114~
and 34a and are received by first, second, and third
outfeed shaft rolls 66, 68, and 70. The pa~h of the
edgings 24', on the other hand, becomes progressively
inclined in a downward direction as the edgings pass
downstream of fith drive roll 22, since they are not
supported in any way. The edgings 24' thus pass below
first, second, and third outfeed rolls 66, 68, and 70,
thereby positively segreating the boards 24 with respect
to the edgings 24'. Eventually, once the trailing edges
of the edgings 24' clear second hold-down roll 28 and a
third drive roll 20, the edgings begin to drop downwardly
into the bin or conveyor means (not shown) disposed below
the edging picker conveyor 10. As mentioned above, fourth
and fifth drivP rolls 21 and 22 continue to convey the
edgings 24' in a downstream direction until the trailing
edge of the edgings pass these drive rolls. In the event
the lumber is stiffer than normal, the edgings 24' may not
drop downwardly until the leading edge contacts edging
shear 72, which wedges the edgings downwardly until the
trailing edge of the edgings clears second hold-down roll
28 and third drive roll 20, at which point the edgings
drop downwardly from the edging picker conveyor 10.
When the boards 24 come into contact with first
and second outfeed shaft rolls 66 and 68, these shaft
rolls begin to take over the drive of the boards. The
boards are subsequently passed on to third outfeed roll 70
and to the additional outfeed roll 80 which, in
combination with other outfeed rolls (not shown), convey
the boards to the next processing station (not shown).
When the trailing edges of the two two-by~four
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~6~
boards 24 and edgings 24' have cleared edger saws 14a,
14b, and 14c, the saws may then receive the next lumber
slab without waiting for the two two-by-fours to clear the
edging picker conveyor 10. Thus, if the next lumber slab
is ~o be cut in~o a two-by-six and a two-by-four, edger
saws 14b and 14c may be repositioned. As noted above, in
many of the prior art designs such transverse shifting of
the edger saws must be delayed until after the previcus
boards clear the edging picker conveyor. The time delay
built into the circuitry, ~hich interconnects the means
for transversely shifting the edger saws and corresponding
means for the lifter arms, provides sufficient time for
the two two-by-four boards 24 to clear ramp lifter arms 32
and 32a. Thus, with edger saws 14b and 14c shifted to the
position depicted in phantom in Figure 1, a two-by-six and
a two~by-four board will be cut. Once the circuit time
delay has passed, normally no lon~er than one to one and a
half seconds, the two-by-four boards 24 will have had time
to clear lifter arms 32 and 32a, thus permitting lifter
arm 32a to be shifted two inches to the position depicted
in phantom in Figures 1 and 3. This two-inch shift is
provided by sending control air to the two-inch section
52a to extend that section of control cylinder 52. By the
time the leading edge of the two-by-six and two-by-four
boards reach lifter arms 32 and 32a, lifter arm 32a is in
position to receive the two-by-four board 24. In the
event that a single two-by-six board is to be cut, the
two-inch section 52a of control cylinder 52 is maintained
in its extended position and the three-inch section 52b is
also ext~nded to shift lifter arm 32a a full five inches
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;3916
from the initial position depicted in solid lines in
Figures 1~ and 3.
The operation thus continues with edger saws 14b
and 14c and lifter arm 32a being transversely shifted as
necessary to saw and handle boards of differing widths.
In the event that only two edger saws are
provided (not shown), it may be possible to include only a
single lifter arm (not shown). However, even with only
two saws it is often desirable to include a second,
transversely adjustable lifter arm to han~le wider boards
such as two-by-twelves. In the event that four or more
edger saws are provided, an additional liftex arm is
normally included for each additional edger saw.
Of course, it should be understood that various
changes and modifications of the preferred embodiments
described herein will be apparent to those skilled in the
art. Such changes and modifications can be made without
departing from the spirit and scope of the present
invention and without diminishing its att~ndant
advantages. It is, therefore, intended that such changes
and modifications be covered by the following claims~
.
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