Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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MISALIGNED ARTICLE DISENGAGEMENT SYSTEM
FOR A DISC SINGULATOR
BACKGROUND
Centrifugal disc singulators, sometimes referred to as rotary disc feeders,
are machines used for
automatically orienting and aligning articles from a disorderly bulk supply
into a single row or
file. Examples of these machines are described, for instance, in US Patents
Nos. 3,224,554 and
5,044,487. Typically, they include a rotating disc which receives the articles
to be aligned in bulk
and moves them toward an output by displacing them radially outwardly due to
centrifugal force.
Although most existing disc singulators have been found satisfactory to a
certain degree, room for
further improvements always exist. For example, some of the articles to be
aligned may
nevertheless proceed through the output while still being misaligned, and then
block the output at
one point. A manual intervention and complete stop of the machine is sometimes
required to
remove such blockages, which results in undesirable down time for the machine.
This is
particularly true in the case of elongated articles.
A system which allowed to alleviate some of these difficulties was presented
by Assignee in
corresponding published US patent application No. 2006/0243561 filed on April
25, 2005 and
entitled "ARTICLE FEEDER AND SPACER". The system includes a sensor to detect
the
presence of a misaligned article, and an arm which is activated to dislodge
the misaligned article
upon detection. Further improvements were still desirable.
SUMMARY
In accordance with one aspect, there is provided a misaligned article
disengagement system for
use at an output of a centrifugal disc singulator in which elongated articles
exit lengthwise
following a substantially tangential output path at a periphery of a rotary
disc, the rotary disc
having a vertical rotation axis and an upper article-receiving area surrounded
by a peripheral wall,
the disengagement system comprising: a lateral conveyor positioned at a
radially-outer side of the
output, the lateral conveyor having an inner portion extending substantially
parallel to the output
path and movable in a direction opposite the output path; and a vertically-
extending fulcrum
member positioned at a radially-inner side of the output and being adjacent to
the inner portion of
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the lateral conveyor; whereby, in use, a misaligned article is moved out of
the output and back to
the article-receiving area of the singulator when a leading end of the
misaligned article engages
the inner portion of the lateral conveyor and a side of the misaligned article
engages the fulcrum
member.
In accordance with an other aspect, there is provided a centrifugal disc
singulator comprising : a
rotary disc having a vertical rotation axis and defining an upper article-
receiving area surrounded
by a peripheral wall and an output in which elongated articles exit lengthwise
following a
substantially tangential output path at a periphery of the rotary disc, a
lateral conveyor positioned
at a radially-outer side of the output, the lateral conveyor having an inner
portion extending
substantially parallel to the output path and movable in a direction opposite
the output path, and a
vertically-extending fulcrum member positioned at a radially-inner side of the
output and being
adjacent to the inner portion of the lateral conveyor.
In accordance with an other aspect, there is provided a method of disengaging
a misaligned article
entering an output of a centrifugal disc singulator having an upper article-
receiving area, the
method comprising : moving a leading end of a misaligned article abutting a
radially-outer side of
the output, the leading end being moved in a direction opposite an output
path; and supporting the
side of the misaligned article along a vertically extending fulcrum member
positioned at a
radially-inner side of the output until the misaligned article goes back into
the article-receiving
area.
DESCRIPTION OF THE FIGURES
Further features and advantages of the present improved misaligned article
disengagement system
will become apparent from the following detailed description, taken in
combination with the
appended figures, in which:
Fig. I is a perspective view of an example of a disc singulator with an
example of the improved
misaligned article disengagement system;
Fig. 2 is a top plan view of the disc singulator shown in Fig. 1;
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Fig. 3 is an enlarged top plan view showing some of the parts at the output of
the disc singulator
of Fig. 1;
Fig. 4 is an isometric view showing the misaligned article disengagement
system of Fig. 1;
Fig. 5 is an isometric view of the lateral conveyor used in the misaligned
article disengagement
system shown in Fig. 4;
Fig. 6 is a view similar to Fig. 5, showing the lateral conveyor from an
opposite side;
Fig. 7 is cross-sectional view taken along line 7-7 of Fig. 2;
Fig. 8 is a cross-sectional view taken along line 8-8 of Fig. 2;
Fig. 9 is a cross-sectional view taken along line 9-9 of Fig. 2;
Figs. 10 to 13 are schematic top plan views successively depicting an example
of the
disengagement of a misaligned article in the disengagement system of Fig. 1.
DETAILED DESCRIPTION
Fig. 1 shows an example of a centrifugal disc singulator 10. The disc
singulator 10 includes a
rotary disc 12 having a vertical rotation axis 14 and defining an upper
article receiving area 16
surrounded by a peripheral wall 18. The rotary disc 12 is supported by a
plurality of spaced-apart
support wheels 20 which are rotatably mounted to a frame 22. A rotary disc
motor 24 is provided
to drive the rotary disc 12 into rotation. In the illustrated example, the
rotation of the disc 12 is in
a counter-clockwise direction when viewed from above. The peripheral wall 18
is also mounted to
the frame 22.
Fig. 2 shows the disc singulator in operation once a bulk supply of wood board
pieces 26 having
various lengths is dropped onto the article receiving area 16. The rotation of
the disc 12 displaces
the wood board pieces 26 toward the peripheral wall 18 due to centrifugal
force. During this
displacement, stacks of wood board pieces 26 from the bulk supply
progressively disaggregate,
and wood board pieces laying on a side tend to fall and lay flat against the
upper surface of the
disc 12. Some of the wood board pieces 26 soon become longitudinally aligned
against the
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peripheral wall 18. However, some wood board pieces 26 can remain in a stacked
configuration
abutting the peripheral wall, and some wood board pieces 26 can laterally abut
against other wood
board pieces 26 and thus be maintained in a misaligned state. Such misaligned
wood board pieces
are not longitudinally aligned against the peripheral wall 18 and laying flat
against the upper
surface of the rotary disc 12. Because of the rotation of the disc 12,
correctly aligned articles 28
follow a tangential output path 30 and lengthwisely engage an output 32 of the
disc singulator 10.
The disc singulator 10 is designed to allow them to exit through the output
32. The function of the
disc singulator 10 is thus to orient and arrange the bulk supply of wood board
pieces 26 so as to
create an orderly file of wood board pieces out the output 32.
Misaligned wood board pieces 33 can lead to blockage at the output 32.
Accordingly, the disc
singulator 10 has a plurality of features to reduce the risks of having the
output blocked, including
a misaligned article disengagement system 38 (on the left-hand side of the
figure) provided to
move misaligned articles engaging the output 32 back to the article receiving
area 16. Articles that
are moved out of the output 32 will be correctly aligned at a later time. The
aim of the misaligned
article disengagement system 38 is to remove and disengage all the wood board
pieces which are
not correctly aligned lengthwise along the peripheral wall 18 from the output
32, and to move
them back to the article receiving area 16 of the disc 12.
In the illustrated example, the misaligned article disengagement system 38 has
a round brush 42, a
lateral conveyor 44 and a vertically extending roller 46 (Fig. 1). The lateral
conveyor 44 is
positioned on a radially outer side of the output 32, whereas the roller 46 is
positioned on a
radially inner side of the output 32, relative to the rotation axis 14 of the
disc 12. Reference to
Figs. 3 and 4 can be made for greater clarity.
The illustrated misaligned article disengagement system 38 also includes a
first pile breaker 36
(on the right hand side of the figure), and a second pile breaker 40 (on the
left hand side of the
figure), provided upstream of the output to move superposed articles back
toward the center of the
disc 12. The first pile breaker 36 and the second pile breaker 40 each include
a respective
conveyor brush 47, 48 which has a lower portion moveable toward the disc
rotation axis. Each
conveyor brush 47, 48 is driven by a corresponding conveyor brush motor via a
conveyor brush
driving mechanism.
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As shown in Fig. 4, in the illustrated example, the round brush 42 is
connected to the driving
mechanism 50 of the conveyor brush 48 of the second pile breaker 40, and is
also driven by the
conveyor brush motor 52. The axis of rotation 54 of the round brush 42 is
substantially horizontal,
and parallel to the output path 30 (Fig. 2). The vertically extending roller
46 is driven by a roller
motor 56. The roller 46 has a frictional outer surface 58. The round brush 42,
lateral conveyor 44,
and roller 46 are all mounted onto an auxiliary frame 60, and the auxiliary
frame 60 is mounted
onto the frame 22 of the disc singulator 10 (Fig. 1).
The lateral conveyor 44 is depicted in greater detail in Figs. 5 and 6. In
this case, the lateral
conveyor 44 is an endless chain 44a, and more particularly, a double width
chain 44b driven by a
chain motor 74. The chain 44a is of double width in the sense that it includes
first and second
adjacent chains 64, 66, thus totalling a double width. In alternate
embodiments, the width of the
chain 44a can be varied by using one or more than two adjacent chains and by
varying their
widths.
The radially-inner portion 68 of the chain 44a (relative to the rotation axis
of the rotary disc) is
backed by a backing plate 70 which is fixed. The chain 44a is slidingly
engaged within the
backing plate 70. Hence if a misaligned article impacts the inner portion 68
of the chain 44a with
force, the impact will be absorbed at least partially by the backing plate 70
rather than by an
increase in tension within the chain 44a.
The endless chain 44a is mounted onto two sprockets : a drive sprocket 72
connected to the chain
motor 74, and an idle sprocket 76. A tension adjustment sprocket 78 is also
used to allow
adjusting the tension in the chain 44a. As can be seen in Fig. 6, the tension
adjustment sprocket 78
is mounted to the frame via a tension adjustment mechanism 80 which allows a
technician to pivot
the tension adjustment sprocket 78 around an offset pivot axis 82 to increase
or decrease the
tension within the chain 44a.
Referring now to Fig. 7, the action of a pile breaker 40 is depicted. The
lower portion 84 of the
conveyor brush 48 is spaced from the rotary disc 12 by only slightly more than
the thickness of a
wood board piece. Therefore, when two or more wood board pieces are
superposed, the
superposed wood board piece is frictionally engaged by the conveyor brush 48
as the stack is
displaced by the rotary disc 12. The bristles of the conveyor brush 48
generate a frictional force
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on the superposed wood board piece which moves the superposed wood board piece
back toward
the center, or rotation axis 14, of the rotary disc 12. If a wood board piece
standing on its edge, or
side, engages the conveyor brush 48, it will typically be tipped over by the
conveyor brush 48 so
as to lay flat against the upper surface 16 of the disc 12.
Referring also to Fig. 8, the conveyor brush 48 and the round brush 42 are
both mounted to a
common displaceable frame portion 86 and can be moved together vertically by
using a height
adjustor 88 and horizontally using a depth adjustor 90. The space defined
between the lower
portion 84 of the conveyor brush and the disc 12 can thus be adjusted to adapt
to different
thicknesses of wood board pieces to be aligned, or for fine tuning, for
example.
The function of the round brush 42 is to displace wood board pieces which are
laying flat on the
disc 12 upper surface but which laterally abut against another wood board
piece. Its function is
also to displace pieces, that are not longitudinally aligned against the
peripheral wall 18, out from
the output path 30, and toward the center of the disc 12. The round brush 42
is thus adjacent the
output path 30 and vertically spaced from the rotary disc 12 by less than the
thickness of a wood
board piece so as to frictionally engage wood board pieces which pass
underneath it. The round
brush 42 is positioned as close as possible to the peripheral wall 18 while
maintaining a space set
so that correctly aligned wood board pieces can still pass by it substantially
unaffected. Correctly
aligned wood board pieces which are carried by the disc 12 in longitudinal
alignment against the
peripheral wall 18 along the output path 30 thus pass in the space defined
between the peripheral
wall 18 and the round brush 42, and remain substantially unaffected by the
round brush 42. Wood
board pieces which are not confined within this space are engaged by the round
brush 42. The
round brush 42 frictionally engages the upper portion of such wood board
pieces, which generates
a frictional force oriented toward the center of the disc 12. Because of the
shape of the round
brush 42, the greatest frictional forces are exerted when wood board pieces
are positioned directly
below the rotation axis thereof. Some wood board pieces which have a
relatively low degree of
misalignment, or on which forces are exerted by adjacent wood board pieces,
may remain
substantially unaffected by the round brush 42 when they first pass by it.
Fig. 9 shows that the lateral conveyor 44 has a radially inner portion 68
which can be slightly
recessed relative to an aperture 92 defined in the peripheral wall 18. The
aperture 92 is at least as
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wide as the thickness of the wood board pieces, so as to allow misaligned wood
board pieces to
contact the lateral conveyor 44. The inner portion 68 is driven in a direction
opposite the output
path of wood board pieces. The roller 46 also has an output path side, or
radially-outer side 94,
which is also driven in a direction opposite the output path. The vertically
extending roller 46 is
spaced from the peripheral wall 18 just enough to allow correctly aligned wood
board pieces to
pass between the lateral conveyor 44 and the roller 46 substantially
unaffected. Hence, although
the lateral conveyor 44 and the vertical roller 46 are driven in a direction
which is opposite the
displacement of correctly aligned wood board pieces, correctly aligned wood
board pieces pass
between the lateral conveyor 44 and the vertical roller 46 and are
substantially unaffected by these
components. The vertically extending roller 46 is said to be on a radially
inner side of the output
32 whereas the lateral conveyor 44 can be said to be on a radially outer side
of the output 32,
relative to the rotation axis 14 of the rotary disc 12.
In use, misaligned wood board pieces 33 can come into contact with the roller
46 and lateral
conveyor 44 as shown in Figs. 10 through 13. The leading end 96 of a
misaligned wood board
piece 33a will come into engagement with the inner portion 68 of the lateral
conveyor 44 and the
side of the misaligned wood board piece 33a will come into engagement with the
roller 46. The
lateral conveyor 44 generates a pivoting force on the leading end 96 of the
misaligned wood board
piece 33a and the roller 46 acts as a fulcrum for the pivoting force created
by the lateral conveyor
44. The combined action of the lateral conveyor 44 and the roller 46 moves the
misaligned article
33a around the roller 46 and toward the center of the disc 12. At one point,
in the illustrated
embodiment, the misaligned article 33a will have a portion passing under the
round brush 42. The
round brush 42 further assists in bringing the misaligned article 33a back to
the article receiving
area.
Beginning with Fig. 10, the substantially tangential output path 30 is
schematically depicted as
having the width of a correctly aligned wood board piece 28 and being
positioned immediately
inward of the peripheral wall 18. The wood board pieces 28 which are correctly
aligned in the
output path 30 are those which longitudinally abut the peripheral wall 18 due
to the centrifugal
action of the rotating disc. Such articles traveling along the output path 30
are referred to as
correctly aligned articles when they lay flat therein. A single file, or row,
of correctly aligned
articles 28 exits the disc singulator through the output 32. In this example,
a single layer of articles
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approaches the output 32 because superposed articles were previously moved
back toward the
center of the rotary table by the brush conveyors. The misaligned article 33a
has a leading edge 96
which abuts against the peripheral wall 18 and a side which abuts against a
correctly aligned
article 28a (Fig. 10).
When the misaligned article engages the output (Fig. 11), the leading end 96
of the misaligned
article 33a engages the inner portion 68 of the lateral conveyor 44. The
lateral conveyor 44
generates a pivoting force to the leading end 96 of the misaligned wood board
piece 33a and tends
to move the trailing end 98 of the wood board piece 33a into fuller engagement
with the round
brush 42. This pivoting movement is assisted by the roller 46, which is
engaged by a side of the
misaligned wood board piece 33a. Hence, the leading edge 96 of the wood board
piece 33a is
displaced in the direction opposite to the output path 30 by the lateral
conveyor 44 and is thus
pivoted around the roller 46. This causes the trailing end 98 of the
misaligned article 33a to
increasingly engage the rotary brush 42 (Figs 11 and 12).
The misaligned wood board piece 33a is eventually moved out from the output 32
by the
combined action of the round brush 42, the rotating roller 46 and also by the
rotary disc 12. Fig.
13 shows the misaligned wood board piece being moved out from the output and
back to the
article receiving area of the rotary disc. The following correctly aligned
article 28a can then
engage the output 32. The correctly aligned article 28a remains substantially
unaffected by the
round brush 42, the lateral conveyor 44 and the roller 46.
The method of disengagement proposed herein thus includes moving the leading
end of the
misaligned article in a direction opposite the output path, along a radially-
outer side of the output,
and thereby pivoting the misaligned article around a vertically extending
fulcrum positioned at a
radially inner side of the output.
For illustrative purposes, in the example given above, the rotary disc 12 can
have a diameter of
about 10 feet and operate at angular speeds in the order of 50 RPM. The wood
board pieces to be
aligned can be trims from standard lengths 2 X 4 wood boards between 0.5 and 3
feet in length.
The endless chain can have a height (or width) of 1 1/2 inches for use with
such wood board
pieces. If larger wood board pieces are used, such as trims from 6X6 boards,
the width of the
endless chain can be increased.
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An advantage of the illustrated embodiment is that it has less risks of
stopping, in the sense that
when the disc singulator is in operation, all of the rotary disc, the brush
conveyors, the round
brush, the roller, and the endless chain can be continuously driven without
interruption.
Having discussed above an example of an improved disc singulator with the
misaligned article
disengagement system, it will now be discussed some alternate configurations.
First, it should be
noted that although the articles to align are wood board pieces in the example
given above, the
present improvements can be adapted for use with other types of elongated
articles than wood
board pieces.
The lateral conveyor can be used with a rubber belt or another kind of
flexible member.
The lateral conveyor can be positioned in alignment with the peripheral wall,
but can also be
slightly recessed within the aperture in the peripheral wall. A recessed
configuration can be used,
for instance, in cases where correctly aligned articles otherwise have a
tendency to engage and be
disturbed by the lateral conveyor.
The fulcrum member can be fixed instead of being driven by a motor. It can
also be rotatable
without being motor driven.
The round brush can be entirely omitted or replaced with an equivalent
displacement device, such
as a rubber flap rotor for example. As discussed, if very long elongated
articles are to be aligned
by the disc singulator, the trailing end portion of these articles may
sufficiently extend toward the
rotation axis of the rotary disc to offer a sufficient lever arm for the
frictional force exerted on the
trailing end of the article by rotary disc to pivot the misaligned article
around the fulcrum member
without the aid of a displacement device.
The improved misaligned article disengagement system can be sold in
combination with a new
disc singulator, but it can also be provided alone, as a retro-fit system for
existing centrifugal disc
singulators.
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As can be seen therefore, the examples described above and illustrated are
intended to be
exemplary only. The scope of the invention(s) is intended to be determined
solely by the
appended claims.
