U.S. patent application number 15/716864 was filed with the patent office on 2018-03-29 for lumber transfer system with individually controlled grasping fingers.
The applicant listed for this patent is CARBOTECH INTERNATIONAL. Invention is credited to Louis BEAUDET, Francis LEPAGE.
Application Number | 20180086568 15/716864 |
Document ID | / |
Family ID | 61633076 |
Filed Date | 2018-03-29 |
United States Patent
Application |
20180086568 |
Kind Code |
A1 |
LEPAGE; Francis ; et
al. |
March 29, 2018 |
LUMBER TRANSFER SYSTEM WITH INDIVIDUALLY CONTROLLED GRASPING
FINGERS
Abstract
A lumber transfer system for transferring pieces of lumber
comprising a feeding conveyor having a conveying surface for
receiving the pieces of lumber; a plurality of grasping assemblies
spaced apart transversely along the conveying surface, each one of
the grasping assemblies comprising a grasping finger able to be
positioned independently for either grasping a piece of lumber
located upstream from the grasping assembly and moving it, or
preventing it from grasping a piece of lumber; a detection system
for detecting a presence of a piece of lumber and producing
signals; and a controller controlling the grasping assemblies for
the grasping fingers to be positioned independently. The lumber
transfer system is therefore able to have only grasping fingers
responsible to grasp the piece of lumber to be in a grasping
position.
Inventors: |
LEPAGE; Francis;
(Dolbeau-Mistassini, CA) ; BEAUDET; Louis;
(Sainte-Sophie-d'Halifax, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CARBOTECH INTERNATIONAL |
Plessisville |
|
CA |
|
|
Family ID: |
61633076 |
Appl. No.: |
15/716864 |
Filed: |
September 27, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62400270 |
Sep 27, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B27B 31/08 20130101;
B27B 31/00 20130101; B65G 2203/041 20130101; B65G 2201/0282
20130101; B65G 43/08 20130101; B65G 47/261 20130101; B65G 2203/044
20130101; B65G 2201/0217 20130101; B65G 2203/0233 20130101; B65G
47/847 20130101 |
International
Class: |
B65G 43/08 20060101
B65G043/08; B65G 47/26 20060101 B65G047/26; B65G 47/86 20060101
B65G047/86 |
Claims
1. A lumber transfer system for transferring longitudinal pieces of
lumber from a feeding conveyor to an outfeed conveyor, the pieces
of lumber being conveyed in a conveying direction which is
substantially transverse to their length, the lumber transfer
system comprising: a detection system adapted for monitoring a
presence of a piece of lumber and for producing detection signals;
grasping assemblies spaced apart transversely relative to the
conveying direction; and a controller, in communication with the
detection system and the grasping assemblies, that receives the
detection signals from the detection system, processes the
detection signals to produce discrete control signals and sends the
discrete control signals to each one of the grasping assemblies;
wherein each one of the grasping assemblies is adapted to
independently adopt, based on the discrete control signals, at
least a grasping position and a stowed position, wherein, in the
grasping position, the grasping assemblies grasps a piece of lumber
to transfer it from the feeding conveyor to the outfeed conveyor,
and wherein, in the stowed position, a piece of lumber remains
ungrasped by the grasping assemblies.
2. The lumber transfer system of claim 1, further comprising a
detection corridor oriented substantially transversely with respect
to the conveying direction, wherein the detection system is adapted
for monitoring a presence of a piece of lumber within the detection
corridor and thereby produce the detection signals.
3. The lumber transfer system of claim 2, wherein the grasping
assemblies are located downstream from the detection corridor.
4. The lumber transfer system of claim 2, wherein the detection
system comprises: a combination of detectors detecting a presence
of a piece of lumber relative to discrete portions of the detection
corridor, and one or more detectors detecting in combination a
presence of a piece of lumber over an entirety of the detection
corridor.
5. The lumber transfer system of claim 1, wherein the detection
system comprises at least one of: a camera, a photocell detector,
and an ultrasound detector.
6. The lumber transfer system of claim 1, wherein the detection
system is contact-free.
7. The lumber transfer system of claim 1, wherein the detection
system comprises a contact-based component detecting a presence of
a piece of lumber upon contact with a piece of lumber.
8. The lumber transfer system of claim 1, wherein each one of the
grasping assemblies comprises a grasping finger adapted for
adopting the grasping position and the stowed position.
9. The lumber transfer system of claim 1, further comprising at
least one of blocking fingers and positioning fingers, wherein the
controller further controls at least one of the blocking fingers
and the positioning fingers.
10. A lumber transfer system for transferring pieces of lumber
along a conveying direction comprising an exit, the lumber transfer
system comprising: a feeding conveyor having a conveying surface
for receiving the pieces of lumber in a substantially transverse
orientation with respect to the conveying direction, and for
conveying the pieces of lumber therealong downstream toward the
exit; grasping assemblies spaced apart transversely along the
conveying surface, each one of the grasping assemblies comprising a
grasping finger able to be positioned independently in a grasping
position and a stowed position, wherein the grasping finger in the
grasping position is capable to grasp a piece of lumber located
upstream from each one of the grasping assemblies and to move the
piece of lumber in a downstream position, and wherein the grasping
finger in the stowed position prevents the grasping finger from
grasping a piece of lumber located upstream therefrom; a detection
system for: detecting a presence of a piece of lumber within a
detection corridor oriented substantially transversely with respect
to the conveying direction and upstream from the grasping
assemblies, and producing detection signals based on detection of a
presence of a piece of lumber; and a controller for receiving the
detection signals from the detection system, processing the
detection signals and sending discrete control signals to the
grasping assemblies for the grasping fingers to be positioned
independently in either one of the grasping position and the stowed
position, wherein the lumber transfer system is able to have only
grasping fingers responsible for grasping the piece of lumber in
the grasping position.
11. The lumber transfer system of claim 10, wherein the grasping
assemblies are spaced apart unevenly.
12. The lumber transfer system of claim 10, wherein the detection
system comprises at least one selected from a group comprising: a
camera, a photocell detector, an ultrasound detector.
13. The lumber transfer system of claim 10, wherein the detection
system is contact-free.
14. The lumber transfer system of claim 10, wherein the detection
system comprises a contact-based component detecting a presence of
a piece of lumber upon contact with a piece of lumber.
15. The lumber transfer system of claim 10, wherein the detection
system for detecting presence of a piece of lumber within the
detection corridor comprises: a combination of detectors detecting
a presence of a piece of lumber relatively to discrete portions of
the detection corridor, and one or more detectors detecting
presence of a piece of lumber over an entirety of the detection
corridor.
16. The lumber transfer system of claim 10, further comprising at
least one of blocking fingers and positioning fingers, wherein the
controller further controls at least one of the blocking fingers
and the positioning fingers.
17. The lumber transfer system of claim 10, further comprising a
shaft driven at a speed with the grasping assemblies being mounted
thereto, wherein the controller further controls the speed of the
shaft.
18. The lumber transfer system of claim 10, further comprising at
least one of a feeding conveyor and an outfeed conveyor, wherein
the controller further controls a speed of one of the feeding
conveyor and the outfeed conveyor.
19. The lumber transfer system of claim 10, wherein the grasping
assemblies further comprise biasing means, wherein the biasing
means forces the grasping fingers in the stowed position when not
actuated.
20. The lumber transfer system of claim 10, wherein each one of the
grasping assemblies further comprises a tooth cooperating with the
grasping finger, wherein the tooth is operable between an extended
position and a contracted position concurrently with a positioning
of the cooperating grasping finger.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from U.S. patent
provisional application 62/400,270 filed Sep. 27, 2016, the
specification of which is hereby incorporated herein by reference
in its entirety.
BACKGROUND
(a) Field
[0002] The subject matter disclosed generally relates to systems
for sorting or unscrambling pieces of lumber and to methods of
operating the same.
(b) Related Prior Art
[0003] It is well known in the art that in a saw mill or a lumber
mill, transportation of the lumber pieces of lumber requires the
use of conveyors. Usually, the pieces of lumber emerge from the
mill in random order onto a feeding conveyor. Certain given stages
of the transformation process require that the pieces of lumber be
regularly spaced apart on a conveyor. It is therefore necessary to
provide a system for transferring the pieces of lumber from the
feeding conveyor to another conveyor such that the pieces of lumber
are regularly spaced thereon. In order to be efficient, lumber
transfer systems should allow handling and transfer of any type,
size and shape of pieces of lumber such as stem, saw log, wood
plank, beam and the like. Furthermore, they should also allow a
high transfer rate of pieces of lumber. In fact, the efficiency of
a lumber mill generally depends greatly on the production rate
attainable. The number of pieces of lumber transferred per minute
from one conveyor to another is thus an important factor affecting
greatly the production rate of lumber mills.
[0004] Examples of transfer lumber systems known to the Applicant
are described in the following Canadian patents and/or patent
applications: 1,171,020; 1,228,873; 2,133,927; 2,148,322;
2,151,768; 2,185,609; 2,185,620; 2,238,231; 2,271,175; and
2,577,656.
[0005] It is also well known in the art that pieces of lumber
arriving on the feeding conveyor prior to being transferred and
equally spaced by the transfer system are often intermingled and
comprise different pieces of various lengths. Prior to being
transferred, the pieces of lumber are accumulated on an
accumulating portion of the feeding conveyor, where typically,
conveying chains roll at high speed. When a short lumber is
followed by a long one, the long lumber has a tendency to pivot
around the short lumber. Since the extremity of the longer lumber
stands out relative to the downstream shorter lumber, this longer
extremity is driven by the chains, and/or in some cases, by a
pushing action of other following pieces of lumber, and this
situation leads to an important problem where the transfer system
will load the long lumber together with the short one, while only
the short lumber should have been transferred. When such problem
occurs, production must be stopped and an operator must space out
and put the pieces of lumber back in order. Such a problem commonly
occurs in lumber mills and affects the overall efficiency of the
mills.
[0006] Hence, in light of the aforementioned, there is a need for
an improved system which, by virtue of its design and components,
would be able to overcome or at least minimize some of the
aforementioned prior art problems.
SUMMARY
[0007] According to an embodiment, there is disclosed a lumber
transfer system for transferring longitudinal pieces of lumber from
a feeding conveyor to an outfeed conveyor, the pieces of lumber
being conveyed in a conveying direction which is substantially
transverse to their length, the lumber transfer system comprising:
a detection system adapted for monitoring a presence of a piece of
lumber and for producing detection signals; grasping assemblies
spaced apart transversely relative to the conveying direction; and
a controller, in communication with the detection system and the
grasping assemblies, that receives the detection signals from the
detection system, processes the detection signals to produce
discrete control signals and sends the discrete control signals to
each one of the grasping assemblies; wherein each one of the
grasping assemblies is adapted to independently adopt, based on the
discrete control signals, at least a grasping position and a stowed
position, wherein, in the grasping position, the grasping
assemblies grasps a piece of lumber to transfer it from the feeding
conveyor to the outfeed conveyor, and wherein, in the stowed
position, a piece of lumber remains ungrasped by the grasping
assemblies.
[0008] According to an aspect, the lumber transfer system further
comprises a detection corridor oriented substantially transversely
with respect to the conveying direction, wherein the detection
system is adapted for monitoring a presence of a piece of lumber
within the detection corridor and thereby produce the detection
signals.
[0009] According to an aspect, the grasping assemblies are located
downstream from the detection corridor.
[0010] According to an aspect, the detection system comprises: a
combination of detectors detecting a presence of a piece of lumber
relative to discrete portions of the detection corridor, and one or
more detectors detecting in combination a presence of a piece of
lumber over an entirety of the detection corridor.
[0011] According to an aspect, the detection system comprises at
least one of: a camera, a photocell detector, and an ultrasound
detector.
[0012] According to an aspect, the detection system is
contact-free.
[0013] According to an aspect, the detection system comprises a
contact-based component detecting a presence of a piece of lumber
upon contact with a piece of lumber.
[0014] According to an aspect, each one of the grasping assemblies
comprises a grasping finger adapted for adopting the grasping
position and the stowed position.
[0015] According to an aspect, the lumber transfer system further
comprises at least one of blocking fingers and positioning fingers,
wherein the controller further controls at least one of the
blocking fingers and the positioning fingers.
[0016] According to an embodiment, there is described a lumber
transfer system for transferring pieces of lumber along a conveying
direction comprising an exit, the lumber transfer system
comprising: a feeding conveyor having a conveying surface for
receiving the pieces of lumber in a substantially transverse
orientation with respect to the conveying direction, and for
conveying the pieces of lumber therealong downstream toward the
exit; grasping assemblies spaced apart transversely along the
conveying surface, each one of the grasping assemblies comprising a
grasping finger able to be positioned independently in a grasping
position and a stowed position, wherein the grasping finger in the
grasping position is capable to grasp a piece of lumber located
upstream from each one of the grasping assemblies and to move the
piece of lumber in a downstream position, and wherein the grasping
finger in the stowed position prevents the grasping finger from
grasping a piece of lumber located upstream therefrom; a detection
system for: detecting a presence of a piece of lumber within a
detection corridor oriented substantially transversely with respect
to the conveying direction and upstream from the grasping
assemblies, and producing detection signals based on detection of a
presence of a piece of lumber; and a controller for receiving the
detection signals from the detection system, processing the
detection signals and sending discrete control signals to the
grasping assemblies for the grasping fingers to be positioned
independently in either one of the grasping position and the stowed
position, wherein the lumber transfer system is able to have only
grasping fingers responsible for grasping the piece of lumber in
the grasping position.
[0017] According to an aspect, the grasping assemblies are spaced
apart unevenly.
[0018] According to an aspect, the detection system comprises at
least one selected from a group comprising: a camera, a photocell
detector, an ultrasound detector.
[0019] According to an aspect, the detection system is
contact-free.
[0020] According to an aspect, the detection system comprises a
contact-based component detecting a presence of a piece of lumber
upon contact with a piece of lumber.
[0021] According to an aspect, the detection system for detecting
presence of a piece of lumber within the detection corridor
comprises: a combination of detectors detecting a presence of a
piece of lumber relatively to discrete portions of the detection
corridor, and one or more detectors detecting presence of a piece
of lumber over an entirety of the detection corridor.
[0022] According to an aspect, the lumber transfer system further
comprises at least one of blocking fingers and positioning fingers,
wherein the controller further controls at least one of the
blocking fingers and the positioning fingers.
[0023] According to an aspect, the lumber transfer system further
comprises a shaft driven at a speed with the grasping assemblies
being mounted thereto, wherein the controller further controls the
speed of the shaft.
[0024] According to an aspect, the lumber transfer system further
comprises at least one of a feeding conveyor and an outfeed
conveyor, wherein the controller further controls a speed of one of
the feeding conveyor and the outfeed conveyor.
[0025] According to an aspect, the grasping assemblies further
comprise biasing means, wherein the biasing means forces the
grasping fingers in the stowed position when not actuated.
[0026] According to an aspect, each one of the grasping assemblies
further comprises a tooth cooperating with the grasping finger,
wherein the tooth is operable between an extended position and a
contracted position concurrently with a positioning of the
cooperating grasping finger.
[0027] According to an embodiment, there is disclosed a lumber
transfer system for transferring pieces of lumber along a conveying
direction comprising an exit, the lumber transfer system
comprising: [0028] a feeding conveyor having a conveying surface
for receiving the pieces of lumber in a substantially transverse
orientation with respect to the conveying direction, and for
conveying the pieces of lumber therealong downstream toward the
exit, the feeding conveyor further comprising a detection corridor
oriented substantially transversely with respect to the conveying
direction; [0029] a detection system adapted for monitoring a
lumber presence within the detection corridor and for producing
detection signals; [0030] grasping assemblies located downstream
from the detection corridor and spaced apart transversely along the
conveying surface, each one of the grasping assemblies comprising a
grasping finger able to be positioned independently in a grasping
position and a stowed position, wherein the grasping position is
for grasping a piece of lumber located upstream from each one of
the grasping assemblies and for moving the piece of lumber in a
downstream position, and wherein the stowed position does not allow
grasping a piece of lumber located upstream from the grasping
finger; and [0031] a controller receiving the detection signals
from the detection system, processing the detection signals and
sending discrete control signals to the grasping assemblies for the
grasping fingers to be positioned independently and accordingly in
either one of the grasping position and the stowed position.
[0032] According to an embodiment, there is disclosed a method for
transferring pieces of lumber along a conveying direction of a
lumber transfer system that comprises: [0033] a detector detecting
lumber presence in a detection corridor transversal to the
conveying direction; [0034] a controller; [0035] grasping motors;
and [0036] grasping fingers individually operable by the grasping
motors and adapted to be positioned in a grasping position for
grasping a piece of lumber and a stowed position for preventing
grasping a piece of lumber, the method comprising the steps of:
[0037] a detector detecting a lumber presence along the detection
corridor; [0038] the detector transmitting a detection signal to a
controller upon detection of a lumber presence indicative of an
occupation of the detection corridor by the piece of lumber; [0039]
the controller transmitting control signals to the gasping motors
based on the received detection signal; [0040] the grasping motors
operating grasping fingers for the grasping fingers positioned
along the conveying direction of the piece of lumber to be
positioned in a grasping position while having grasping fingers
outside the conveying direction of the piece of lumber in a stowed
position; and [0041] the grasping fingers moving the piece of
lumber downstream along the conveying direction.
[0042] According to an aspect, the method further comprises
transmitting, by the controller, control signals to one of: [0043]
a motor driving a feeding conveyor conveying the pieces of lumber
upstream toward the grasping fingers; [0044] a motor driving an
outfeed conveyor conveying the pieces of lumber downstream away
from the grasping fingers; and [0045] a motor driving a shaft
having disks mounted thereto, wherein the grasping fingers are
mounted to the disks.
[0046] According to an aspect, the method further comprises
transmitting, by the controller, control signals to one of: [0047]
a blocking finger controller controlling positions of blocking
fingers located upstream from the grasping fingers along the
conveying direction; and [0048] a positioning finger controller
controlling positions of positioning fingers located upstream from
the grasping fingers along the conveying direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0049] Further features and advantages of the present disclosure
will become apparent from the following detailed description, taken
in combination with the appended drawings, in which:
[0050] FIG. 1 is a perspective view of a lumber transfer system,
comprising a close-up of grasping assemblies, according to an
embodiment;
[0051] FIG. 2 is a schematic top view of a portion of a lumber
transfer system according to another embodiment, the lumber
transfer system being shown along with pieces of lumber of
different lengths which may be processed with the lumber transfer
system;
[0052] FIG. 3 is a side view of a portion of the lumber transfer
system shown in FIG. 1;
[0053] FIG. 4 is an enlarged view of a portion of what is shown in
FIG. 3;
[0054] FIG. 5 is a schematic view of steps involved in performing
the improved method according to an embodiment;
[0055] FIG. 6 is a front perspective view showing a grasping motor
mounted to one side of a disk;
[0056] FIG. 7 is a front perspective view showing a plurality of
grasping motors mounted to one side of a disk;
[0057] FIG. 8 is top perspective view showing a top view of a disk
on which fixed teeth and grasping fingers are mounted;
[0058] FIG. 9 is a front perspective view showing a controller,
comprising its display, according to an embodiment;
[0059] FIG. 10 is a side perspective view of the lumber transfer
system of an embodiment at a first step when a piece of lumber is
about to be grasped by grasping fingers;
[0060] FIG. 11 is a side perspective view of the lumber transfer
system of FIG. 10 when the piece of lumber is grasped by grasping
fingers; and
[0061] FIG. 12 is a side perspective view of the lumber transfer
system of FIGS. 10 and 11 at a later time when the grasping fingers
have released their grip on the piece of lumber.
[0062] It will be noted that throughout the appended drawings, like
features are identified by like reference numerals.
DETAILED DESCRIPTION
[0063] In the following description, the same numerical references
refer to similar elements. The embodiments, geometrical
configurations, materials mentioned and/or dimensions shown in the
figures or described in the present description are embodiments
only, given for exemplification purposes only.
[0064] Furthermore, to preserve the clarity of the drawings, some
reference numerals may have been omitted if they were already
identified in a preceding figure.
[0065] Moreover, although the embodiments describe herein were
primarily designed for improving the conveyance or transfer of
pieces of lumber from a feeding conveyor to an outfeed conveyor in
a lumber mill, it may be used with other types of objects and for
other purposes, in other fields, as apparent to a person skilled in
the art. For this reason, expressions such as "conveying",
"transferring", "lumber", "mill", etc., used herein should not be
taken as to limit the scope of the present embodiments and includes
all other kinds of objects or fields with which the present
embodiments could be used and may be useful.
[0066] Moreover, in the context of the present description, the
expressions "system", "assembly", "unit", "device" and any other
equivalent expression and/or compound words thereof known in the
art will be used interchangeably. Furthermore, the same applies for
any other mutually equivalent expressions, such as "lumber",
"elongated piece of lumber", "log", "plank", "board" and the like,
or "segment", "portion" and "section", as well as "unblocked" and
"conveying", for example, as also apparent to a person skilled in
the art. Furthermore, and also in the context of the present
description, the expressions "align", "orientate", "place" and
"space" may also be used interchangeably, or even "second",
"subsequent" and "upstream", as also apparent to a person skilled
in the art.
[0067] In addition, although embodiments as illustrated in the
accompanying drawings may comprise various components, and although
the embodiments of the lumber transfer system as shown consists of
certain geometrical configurations as explained and illustrated
herein, not all of these components and geometries are essential to
the embodiments and thus should not be taken in their restrictive
sense, i.e., should not be taken as to limit the scope of the
present description. It is to be understood, as also apparent to a
person skilled in the art, that other suitable components and
cooperation therebetween, as well as other suitable geometrical
configurations may be used for the lumber transfer system and
corresponding parts according to the present description, as will
be briefly explained hereinafter and as can be easily inferred
herefrom by a person skilled in the art, without departing from the
scope of the description.
[0068] Broadly described, the present description, as illustrated
in the accompanying drawings, relates to a lumber transfer system
for improving the transfer of pieces of lumber from a feeding
conveyor to an outfeed conveyor.
[0069] As previously explained, and as will be understood in
greater detail hereinafter, the present embodiments are a
substantial improvement over conventional lumber transfer systems
or methods in that they comprise components and features that
enable to control individually grasping fingers in response to
detection signals so as to improve handling of pieces of lumber of
different length and thereby to prevent a portion of a longer piece
of lumber that has advanced at the level of a shorter piece of
lumber immediately downstream to the longer one to be grasped along
with the shorter piece of lumber, and therefore preventing the
longer piece of lumber from being grasped and transferred into the
outfeed conveyor with the shorter piece of lumber.
[0070] An advantage resulting from the present embodiments is that
human intervention is substantially reduced in order to ensure a
proper alignment between a pair of neighbouring pieces of lumber
(i.e. a pair of first and second pieces of lumber, the first one
being conveyed downstream, and the second or "subsequent" one,
following upstream along the conveyor), especially in cases when
one is much longer than the other, and that the resulting parallel
pieces of lumber having thus been realigned or reoriented by the
lumber transfer system can thus be individually transferred from
the feeding conveyor to a outfeed conveyor in a much improved
manner (faster, more reliable, etc.), thereby significantly
improving productivity and other desirable factors related to the
operation of a mill.
[0071] Referring to FIG. 1, there is shown a lumber transfer system
10 according to an embodiment. The lumber transfer system 10 is
used for individually transferring substantially parallel and
longitudinal pieces of lumber 12 from a feeding conveyor 14 to an
outfeed conveyor 16, and regularly spacing the pieces of lumber 12
on said outfeed conveyor 16.
[0072] According to an embodiment, the lumber transfer system 10
includes: a feeding conveyor 14; blocking fingers 18 and/or
positioning fingers 44 for stopping a piece of lumber 12 at some
locations on the conveying surface 26; a plurality of grasping
assemblies 22 for regularly transferring the pieces of lumber 12
onto an outfeed conveyor 16 for conveying the transferred and
regularly spaced pieces of lumber 12; and a controller 24 for
synchronizing the overall operation of the lumber transfer system
10.
[0073] The feeding conveyor 14, e.g., a belt or a chain conveyor,
has a longitudinal conveying surface 26 (best shown in FIG. 3) over
which substantially parallel pieces of lumber 12 are conveyed.
Typically, the feeding conveyor 14 receives pieces of lumber 12
accumulating thereon from a plant conveyor which is part of the
mill. The pieces of lumber 12 may be intermingled and are generally
of various lengths and widths. Although it is not a prerequisite,
the pieces of lumber 12 conveyed on the feeding conveyor 14 are
aligned on one reference side 32 (often referred to as the 0''
side). Alternatively, the pieces of lumber 12 may be placed at any
suitable position. For example, the pieces of lumber 12 may be
centered or unpredictably positioned with respect to the conveying
surface 26. As shown, the pieces of lumber 12 are conveyed in a
direction transverse to their length.
[0074] Now additionally referring to FIGS. 4 and 5, a detection
system comprising detector(s) 28, hereinafter detectors 28 for
description purpose, is used for monitoring a lumber presence (a
presence of a piece of lumber) along a detection corridor 30 (shown
in FIGS. 2 and 3) of the longitudinal conveying surface 26 of the
feeding conveyor 14. The detectors 28 are located transversally to
the surface 26, in line with one another. Although, according to
alternative embodiments, other suitable dispositions may be used as
it may be apparent to a person skilled in the art.
[0075] According to an embodiment, the detection corridor 30
consists of a detection line. According to alternative embodiments,
the detection corridor 30 consists of an area, or a lane having a
predetermined width, extending continuously or partially from one
side to the other of the longitudinal surface, and over which each
piece of lumber 12 conveyed will pass or cross. Preferably, while
not in a limiting manner, the detection corridor 30 is a
substantially straight line substantially transversal to the
conveyed direction (aka the conveying direction).
[0076] According to other embodiments, the detectors 28 may be of
many kinds, such as photocells detectors, ultrasound detectors or a
single one or a plurality of cameras, which are able to detect a
presence of a piece of lumber in the detection corridor 30. While
contact-free detection technology is preferred, contact-based
detection solutions producing when contacted by a piece of lumber
12 a may also be used.
[0077] The detectors 28 are placed according to a first embodiment
along the detection corridor 30, underneath the conveying surface
26. According to an alternative embodiment, they are positioned
over the conveying surface or on the side of each belt forming the
conveying surface 26. Moreover, according to alternative
embodiment, the detectors 28 are positioned at any suitable
distance of the conveying surface 26, so long as they each
adequately detect the presence of a piece of lumber within the
associated segment of the detection corridor 30. According to an
embodiment, the detectors 28 are installed as a combination of
detectors 28 detecting a presence of a piece of lumber relatively
to discrete portions (sub-sections) of the detection corridor 30
that do not cover the whole detection corridor 30 but are
indicative of presence and length of pieces of lumber 12 within the
detection corridor 30. According to an embodiment, the detectors 28
are detecting, in combination, presence of a piece of lumber over
the whole detection corridor 30.
[0078] By lumber presence, it is understood that the detectors 28
will detect the presence of a lumber segment or portion in the
"field of view" or "field of detection" of the detectors 28. In
other words, the detectors 28 provide indication as to where up to
a piece of lumber 12 extends from the reference side 32 (a.k.a. 0''
side) along at least a portion of the transverse detecting corridor
30. As illustrated in FIG. 5, the reference side 32 of the
conveying surface 26 can be considered as an X-axis, each piece of
lumber 12 having (by default) one end aligned with the axis, and
the other end of the pieces of lumber 12 extending to a different
length Y. For example, in the embodiment illustrated in FIG. 5,
nine detectors 28 are shown. Starting from the reference side 32
(illustrated as the X-axis), if the first two detectors 28 detect a
lumber presence, and the subsequent detectors 28 (third detector to
the ninth one) do not detect any lumber presence, it can be
considered that the piece of lumber's length extends from the 0''
position, namely the reference side 32, to a length Yi, in the
interval between the second and third detectors 28. It is worth
mentioning that depending on the applications for which the lumber
transfer system 10 is intended for, the detectors 28 are equally
spaced from one another or spaced by discrete uneven distances.
[0079] According to an embodiment, the detection system is adapted
to detect the presence, orientation and/or length of the pieces of
lumber 12 located in a detection corridor 30 defined as a grasping
area close to the grasping assembly 22. Detection of the length
means detection of the length of the piece of lumber 12 as
substantially the positions of the ends of the piece of lumber 12
along the Y-axis. Accordingly, the detection system is able to
detect the presence, the number, the orientation and the distance
between the pieces of lumber 12 in the detection corridor 30 close
to the grasping area. Accordingly, the detection system is adapted
to detect which of the grasping assemblies 22 are aligned to the
piece of lumber 12 to be grasped.
[0080] According to an embodiment, other suitable detecting means,
such as a scanner, is used for recognizing a given profile of a
piece of piece of lumber 12, and comparing it with the profile of a
subsequent piece of piece of lumber 12, in order to selectively,
independently and operatively detect presence and relative
positioning of both pieces of piece of lumber 12.
[0081] The detection system further comprises a controller 24.
According to an embodiment, each one of the detectors 28 is
individually linked, connected or coupled, by wire, to at least one
input component 40 of a controller 24. According to another
embodiment, wireless connections link at least some of the
detectors 28 to the controller 24. The controller 24 is adapted to
receive through the input components 40 signals from the detectors
28, to process individually and independently the signals received
from each of the detectors 28 to produce discrete control signals,
and to send accordingly the discrete control signals via output
components 42 to the motorized blocking fingers 18 and via output
components 43 to the grasping assemblies 22. The discrete control
signals can be sent to the motorized blocking fingers 18 and the
grasping assemblies 22 via dedicated signal paths for each one of
the motorized blocking fingers 18 and the grasping assemblies 22,
via a daisy chain type signal path arrangement, or via an
addressable bus accessible by each one of the motorized blocking
fingers 18 and the grasping assemblies 22 where each one the
motorized blocking fingers 18 and the grasping assemblies 22 has a
unique address.
[0082] According to an embodiment, control signals are sent in
response to the detecting signals, for moving the respective
blocking fingers 18 for which a lumber presence is detected from a
blocking to an unblocking position and otherwise keeping the
respective motorized blocking fingers 18 in their blocking
position. Between each longitudinal piece of lumber 12 detected,
the blocking fingers 18 may be kept in an unblocking position, or
may return to a blocking position.
[0083] Referring additionally to FIG. 9, the controller 24 is
housed as in control box, aside the feeding conveyor 14. The
controller 24 features a monitor 58 on which status of the grasping
assemblies 22 is displayed. Controls, such as touch screen
controls, are used to individually turn on, turn off, test
components of the lumber transfer system 10 connected to the
controller 24, and/or force the positioning of the grasping fingers
into a selected position. According to alternative embodiments,
alternative housing, location, interface and/or command controls
are used for the controller 24.
[0084] As illustrated, the lumber transfer system 10 comprises
blocking fingers 18 and positioning fingers 44 disposed at diverse
locations along the conveying surface 26. These blocking fingers 18
and positioning fingers 44 are for hindering controllably the
course of the pieces of lumber 12 on the conveying surface 26 to
obtain a desired configuration of travelling pieces of lumber 12 on
the conveying surface 26. In other embodiments, one or both of the
blocking fingers 18 and the positioning fingers 44 are absent from
the lumber transfer system 10. Furthermore, the blocking fingers 18
and/or the positioning fingers 44 can be activated controllably
between a first position and a second position under control of a
positioning controller. The positioning controller responsible for
the positioning of the blocking fingers 18 and the positioning
fingers 44 is, according to an embodiment, a single controller, and
according to an embodiment, embodied as the controller 24
responsible for the positioning of the grasping fingers 46.
According to an embodiment, the positioning controller is distinct
from the controller 24.
[0085] According to an embodiment of the lumber transfer system 10
featuring positioning fingers 44, the positioning fingers 44 are
placed right after (or in other words "downstream of") the blocking
fingers 18, before (or in other words "upstream of") the grasping
fingers 46. The positioning fingers 44 are for lying up or halting
the pieces of lumber 12 that have passed the blocking fingers 18
(when present) in the proper location and position so that they may
be adequately grasped or pinched by the grasping assemblies 22.
[0086] Thus, the normal course of the pieces of lumber 12 consists
in the pieces of lumber 12 travelling from the feeding conveyor 14,
to the blocking fingers 18 (when present), freed by the blocking
fingers 18 (when present), and then halted by the positioning
fingers 44 (when present) where the pieces of lumber 12 are grasped
between the teeth 48 and the grasping fingers 46 of multiple
grasping assemblies 22 and regularly transferred onto the outfeed
conveyor 16. That process goes smoothly since the disks 38 and
outfeed conveyor belts rotate at an even and predetermined
speed.
[0087] In addition, FIGS. 6 to 8 illustrate the motorized grasping
assemblies 22. The grasping assemblies 22 are located downstream of
the detection corridor 30, or in other words somewhere between the
detection corridor 30 and the exit 20 of the feeding conveyor 14.
The grasping assemblies 22 are adapted for grasping a piece of
lumber 12 and transferring the piece of lumber 12 to a downstream
portion of the lumber transfer system 10. The grasping fingers 46
mounted to the disks 38 where they are awaiting to transfer the
piece of lumber 12 from an upstream portion of the lumber transfer
system 10 to a downstream portion of the lumber transfer system 10.
The grasping assemblies 22 are aligned with each other, thereby
having the disks 38 aligned with one another. The disks 38 are
further mounted concurrently to a common disk shaft 50. According
to an embodiment, each one of the grasping assemblies 22 comprises
a grasping finger 46, a tooth 48 and a grasping motor 52.
[0088] Regarding the grasping assemblies 22, each one of the
grasping assemblies 22 comprises a grasping finger 46 that is
individually controllable between a grasping position and a stowed
position; the grasping position consisting in a raised position
wherein the grasping finger 46 is able, in collaboration with a
tooth 48, to grasp or pinch a piece of lumber 12, while the stowed
position consisting in a laid down position wherein the gasping
finger 46 has its top face beneath or close to the outer surface of
the disk 38 and wherein one piece of lumber 12 being located close
to the disk 38 would not be grasped by the gasping finger 46.
[0089] Each gasping assembly 22 further comprises a tooth 48. The
grasping finger 46 and the tooth 48 operate in collaboration as
pliers, each defining a plier surface facing each other and adapted
to grasp or pinch the pieces of lumber 12 and to hold the piece of
lumber 12 while moving the piece of lumber 12 downstream. The tooth
48 and the gasping finger 46 are designed such as to have the
strength and the grip qualities for grasping a piece of lumber 12
between the two plier surfaces and for moving and holding a piece
of lumber 12 from a portion of the conveying surface 26 upstream to
the disks 38 to a portion of the conveying surface 26 downstream
from the disks 38 (that may be above the upstream location as
illustrated on FIG. 3). According to non-limiting embodiments, the
tooth 48 and the grasping finger 46 are made of steel, and features
ridges on the plier surfaces to provide the desired non-slippery
surface.
[0090] The grasping assemblies 22 are, according to an embodiment,
mounted to disks 38. A plurality of grasping assemblies 22 are
mounted to each disk 38; the grasping assemblies 22 being disposed
at different angles along the periphery of the disks 38. The
grasping assemblies 22 are designed to operate with the disks 38
rotating in a single direction, with one grasping assembly 22
taking the relay once the rotation of the disks 38 has moved a
grasping assembly 22 in a non-operative angle.
[0091] An operating range is defined for each of the grasping
assemblies 22. The operating range begins with the angle in which
the grasping assembly 22 can grasp a piece of lumber 12 and the
operating range ends with the angle in which the grasping assembly
22 releases the grasped piece of lumber 12 over the downstream
portion of the conveying surface 26. For instance, an operative
range of sixty (60) degrees could be defined as extending from zero
(0) degrees to sixty (60) degrees. According to embodiments, the
operating ranges of neighbor grasping assemblies 22 are slightly
overlapping or not. Operating ranges and overlapping degrees are
function of characteristics of the pieces of lumber 12 to be
grasped.
[0092] In order to operate, the grasping fingers 46 are moved
controllably between a grasping position and a stowed position. A
series of gasping motors 52 are driving individually the grasping
fingers 46 between the grasping position and the stowed position.
The grasping motors 52 are mounted to the disks 38 and connected
one to one to the gasping fingers 46. The grasping motors 52 are
more precisely van-type rotary actuators driven by hydraulic or
pneumatic power. The rotary actuators perform a controlled rotary
motion that is transmitted to the grasping fingers through the
control arm 54 discussed hereinafter.
[0093] As discussed, the disks 38 typically feature a plurality of
grasping assemblies 22. The grasping motors 52 are connected to the
grasping fingers 46 through a control pivot axis 62, with the
control of the position of the control pivot axis 62 permitting to
control the orientation of the gasping fingers 46, thus the
positioning of the grasping fingers 46. Cooperatively to each
grasping finger 46, a tooth 48 is mounted in a stationary manner to
the disk 38.
[0094] According to an embodiment, the tooth 48 are mounted to the
disks 38 in a slidable manner. The tooth 48 are able to slide
between an extended position (acting in collaboration with the
gasping fingers 46 as pliers) and a contracted position. The tooth
48 are operatively connected to the grasping motors 52, the
grasping motors 52 actuating concurrently a grasping finger 46 and
its cooperating tooth 48 to move in a grasping position and an
extended position. The contacted tooth 48, with the present
embodiment, is out of the path of any piece of lumber 12 not to be
grasped.
[0095] Now referring particularly to FIG. 8, each grasping finger
46 is mounted on a first side of a disk 38 according to a control
pivot axis 62. A control arm 54 connects the grasping finger 46 to
the control pivot axis 62, controlling the position of the grasping
finger 46 through rotation of the control arm 54. The plier surface
of the grasping finger 46 is located distant from the control pivot
axis 62 on the opposite portion of the grasping finger 46. The disk
38 has an oblong opening 56 for the passage of a control arm 54
connecting the grasping motor 52 (mounted to the opposite side of
the disks 38) to the grasping finger 46 at the control pivot axis
62. The shape of the opening 56 is for allowing, when connection
and positioning initially the pieces together, fine positioning of
the grasping finger 46 and therefore having the grasping finger 46
capable of occupying the desired grasping and stowed positions.
[0096] An abutment 60 presents an abutment surface to ensure that
the grasping finger 46, when in a grasping position, does not
"open" over a predetermined range.
[0097] According to an embodiment, the control pivot axis 62 is
located on the same side of the abutment 60 as the portion of the
grasping finger 46 featuring the plier surface. The abutment 60 is
located, according to this embodiment, at one end of the grasping
finger 46 with the plier surface being located substantially at the
other end of the grasping finger 46. The control pivot axis 62 and
other attachments responsible for the positioning of the grasping
fingers 46 are located in between.
[0098] Referring back to FIGS. 6 to 8, the tooth 48 and the
grasping finger 46 are mounted on opposed sides of the disk 38, the
latter being located on the same side as the grasping motor 52. The
tooth 48 is mounted to the other side of the disk 38 provides space
for the grasping finger 46 to rotate around its finger pivot axis
62 without the tooth 48 hindering its rotation. According to
another embodiment, the tooth 48 and the grasping finger 46 are
mounted on the same side of the disk 38.
[0099] The number of disks 38 to which are mounted the grasping
assemblies 22 is at least two (2). Accordingly, a plurality of
grasping assemblies 22 work together to move a piece of lumber 12
downstream the conveying surface 26, and some of the grasping
assemblies 22 may have grasping fingers 46 in a stowed position for
facing pieces of lumber 12 of different length. Preferably, the
number of disks 38 to which are mounted the grasping assemblies 22
is at least three (3) so that one grasping assembly 22 may be in a
stowed position while at least two (2) grasping assemblies 22 grasp
a piece of lumber 12. Typically, the number of disks may be about
six (6).
[0100] Typically, the disks 38 on which are mounted grasping
assemblies 22 rotate concurrently through their mounting to a
common disk shaft 50 driving concurrently the plurality of disks
38; the disk shaft 50 being driven by a motor (not shown) or the
like.
[0101] According to an embodiment, the number of grasping
assemblies 22 mounted to the disks 38 is six (6). According to that
embodiment, the grasping assemblies 22 are evenly distributed on
the mounting disks 38. According to an embodiment, grasping fingers
46 mounted to at least two (2) distinct disks 38 of the lumber
transfer system 10 are in phase or at the same angle and enabled to
operate concurrently. In other words, the grasping fingers 46 are
mounted to the disks 38 as to be located in an operating grasping
angle in a synchronous manner. According to an embodiment, the
grasping fingers 46 are evenly distributed over the mounting disks
38.
[0102] Regarding the control of the grasping assemblies 22,
according to an embodiment, both the detectors 28 and the finger
motorizing components (the grasping motors 52 controlling the
positioning of the grasping fingers 46) are connected to the
controller 24 (as shown in FIG. 4), which is a PLC (Programmable
Logic Controller). The controller 24 consists of a single PLC.
Alternatively, the controller 24 comprises, or is distributed over,
multiple PLCs. Of course, other types of controllers may be used,
such as a server or a PC (personal computer) or in its simplest
form, a connecting switch board for interconnecting relays.
[0103] In addition to input components 40 for receiving signals
from the detectors 28, the controller 24 is provided with output
components 43 for sending independently discrete control signals to
each one of the grasping motors 52 (or other controllable
components responsible for positioning the grasping fingers 46).
The discrete control signals, one per grasping assembly 22, are
determined and sent based on processing of the signals received
from the detectors 28, for positioning the respective grasping
fingers 46 in view of whether or not the presence of a piece of
lumber 12 is detected (i.e., the status of the detected piece of
lumber 12). After operation, i.e., after a grasping finger 46 moves
beyond a lumber grasping angle and a releasing angle (thus outside
the operating range of a grasping assembly 22), the grasping
fingers 46 can move to a default position or can remain in last
operating position based on signals received.
[0104] According to an embodiment, the rotation of the disks 38 is
also controlled by the controller 24. According to an embodiment,
the feeding conveyor 14, the positioning fingers 44, the grasping
assemblies 22 and the outfeed conveyor 16 as the motors driving
these different components are all connected to the controller 24,
which controls, manages and synchronizes the overall operation of
the transfer lumber system 10, including the speed of the feeding
conveyor 14, the speed of the outfeed conveyor 16, the speed of the
disks 36, and the speed of the grasping assemblies 22, as can be
easily understood by a person skilled in the art.
[0105] Referring now to FIGS. 10 to 12, these figures are showing
moments during a sequence when a piece of lumber 12 is transferred
by grasping fingers 46 of the lumber transfer system 10 from an
upstream position relatively to the disks 38 to a downstream
position. FIG. 10 shows a first moment when the piece of lumber 12
is located upstream from the disks 38 and about to be grasped by
grasping fingers 46. FIG. 11 shows the piece of lumber 12 when
grasped by grasping fingers 46. FIG. 12 shows the piece of lumber
12 ata later time when the grasping fingers 46 have released their
grip on the piece of lumber 12 and at which time the piece of
lumber 12 is about to be moved on the conveying surface 26
downstream to the disks 38.
[0106] According to an alternative embodiment (not shown),
displacement of each gasping finger 46 is performed by a cylinder
(hydraulic or pneumatic) mounted on the same side of the disk 38 as
the grasping finger 46; the cylinder being secured pivotally to the
grasping finger 46 at the control pivot axis 62 at one of its ends
and secured pivotally to a lug (not shown) extending from the disk
38 at the other of its ends. The cylinder is controllably driven by
pressured fluid (hydraulic or pneumatic) fed by a pump to the
cylinder through tubing with a controllable valve controlling the
fluid fed to the cylinder. The pump is typically located on the
other side of the disk 38 with the feeding tubes passing through
the disks 38 through openings. The controller 24 is linked to the
valve, with the valve opening and closing based on control signals
received from the controller 24.
[0107] According to an embodiment (not shown), a bias component
such as a spring is secured to each of the grasping finger 46. The
spring biases the grasping finger 46 in a default position, namely
the stowed position. Therefore, upon failure of a component
powering the grasping fingers 46, the grasping fingers 46 will not
contact any other component which would potentially result in
premature wearing or component breakage.
[0108] According to an embodiment (not shown), the grasping
assemblies 22 are grouped based on phase, wherein two grasping
assemblies 22 operating at the same angle, thus potentially
concurrently, are considered in phase and are part of the same
"phase". According to this embodiment, a number of pumps (pneumatic
or hydraulic) that is at least equal to the greater of the number
of phases and the number of disks 38 is used to drive the grasping
assemblies 22. A tubing circuit couples a pump to a single grasping
assembly 22 per phase. Further, a controllable valve is associated
with each grasping assembly 22. Accordingly, under control of the
controller 24, the cylinders of all "in-phase" grasping assemblies
22 that are in operating angle may modify the position of the
grasping fingers 46 while being individually powered by a single
pump. Based on the locations of the pumps (for instance grouped at
one end of the disk shaft 50), the circuit of tubes coupled to a
same pump could travel along the disk shaft 50 in a twisted path
around the disk shaft 50 to power per disk 38 a "once de-phased"
cylinder relatively to the previous disk-mounted cylinder.
[0109] According to an embodiment, the outfeed conveyor 16 is a
belt conveyor. According to an alternative embodiment, it consists
of a chain conveyor. Accordingly, the outfeed conveyor 16 is
connected to a downstream lug chain provided with pegs, where
individual transferred pieces of lumber 12 are placed, in between
two subsequent pegs.
[0110] Referring to FIG. 5, there is described a method or process
for individually transferring the substantially parallel pieces of
lumber 12 from the feeding conveyor to the outfeed conveyor.
[0111] The process comprises a first step of monitoring a lumber
presence along the detection corridor 30 on the longitudinal
conveying surface 26 of the feeding conveyor 14 using the detectors
28 placed transversally to the conveying surface 26.
[0112] A second step comprises the controller 24 receiving signals
from the detectors 28. According to an embodiment, each one of the
detectors 28 is respectively associated to a grasping assembly 22.
The motorized grasping fingers 46 of the grasping assemblies 22 are
capable of moving between a grasping position and a stowed
position.
[0113] A third step comprises the controller 24 sending
independently discrete control signals to the grasping motors 52.
The controller 24 sends the discrete control signals for
independently positioning the grasping fingers 46 in a grasping
position when a lumber presence is detected in the corresponding
section of the detection corridor 30 and when the detected piece of
lumber 12 is to be grasped. For other grasping assemblies 22 with
no lumber presence being detected in the corresponding section of
the detection corridor 30, the grasping finger 46 are typically
forced to take the stowed position. According to alternative
embodiments, the grasping finger 46 are remaining in the same
position. Otherwise, when a lumber presence is detected in the
corresponding section of the detection corridor and the detected
piece of lumber 12 is not to be grasped, the grasping finger 46 is
positioned in the stowed position.
[0114] As can be easily understood from the above-described, the
embodiments of the lumber transfer system 10 illustrated in the
accompanying drawings are intended for minimizing components and
assembling steps, while providing a suitable manner for easily,
quickly and efficiently transferring pieces of lumber 12 from a
feeding conveyor 14 to an outfeed conveyor 16.
[0115] The lumber transfer system 10 and corresponding parts are
made of substantially rigid materials, such as metallic materials
(stainless steel, cast iron, etc.), hardened polymers, composite
materials, polymeric materials, and/or the like, so as to ensure a
proper operation thereof depending on the particular applications
for which the lumber transfer system 10 is intended and the
different parameters in cause, as apparent to a person skilled in
the art.
[0116] As may now be appreciated, the present embodiments are a
substantial improvement over the lumber transfer systems of the
prior art in that, by virtue of its design and components, as
briefly explained herein, the lumber transfer system 10 according
to the present embodiments enables to individually control grasping
fingers 46 in response to corresponding detection signals so as to
prevent a portion of a longer piece of lumber to pivot around the
extremity of a shorter downstream piece of lumber, in order to
prevent the longer piece of lumber from being grasped and
transferred into the outfeed conveyor 16 with the shorter piece of
lumber.
[0117] Another advantage resulting from the present embodiments is
that human intervention is substantially reduced in order to ensure
a proper alignment between a pair of neighbouring pieces of lumber,
especially in cases when one is much longer than the other, and
that the resulting parallel pieces of lumber can be thus be
individually transferred from the feeding conveyor to a outfeed
conveyor in a much improved manner (faster, more reliable, etc.),
thereby significantly improving productivity and other desirable
factors related to the operation of a mill.
[0118] Of course, numerous modifications could be made to the
above-described embodiments without departing from the scope of the
description, as apparent to a person skilled in the art.
* * * * *