Note: Descriptions are shown in the official language in which they were submitted.
APPARATUS AND METHOD FOR DELIVERING WOOD PLANKS
TO A TRANSVERSE BAR CONVEYOR-TYPE MACHINE
TECHNICAL FIELD
[0001] The application relates generally to hardwood manufacturing machines
and
processes and, more particularly, to delivering wood planks to transverse bar
conveyor-
type machines such as end matchers.
BACKGROUND OF THE ART
[0002] In a typical hardwood manufacturing process, hardwood planks exiting
moulder
machines require their ends to be machined. Such hardwood planks are therefore
directed, via a conveyor system, to an end matcher. Such end matchers include
parallel
spaced-apart bars, transversely moving over a fixed surface, for ferrying
planks in a
transverse direction and end-profilers positioned at either parallel
extremities for
machining such planks to the required dimensions. End matchers sometimes
comprises
side-shift rollers, over which the parallel spaced-apart bars are transversely
moving, for
positioning the hardwood planks in a parallel direction within the spaced-
apart bars. In
such end matchers, no more than 1 plank can be positioned between adjacent
parallel
spaced-apart bars; the machine that feeds the planks to the end matcher (known
as the
"Plank Feeder"), more specifically that deposits the planks in between the
moving
adjacent parallel spaced-apart bars, is therefore an important element of the
hardwood
manufacturing process.
[0003] In a first type of well-known end matchers, the Plank Feeder delivers
planks to
the end matcher in a perpendicular direction to the moving parallel spaced-
apart bars of
the end matcher, through the use of a linear feed conveyor positioned
vertically
substantially parallel to the end matcher, as shown, for example, in US
6,945,410
("Stibbard"); such a system however is limited in terms of efficiency (from
the point of
view of being able to feed planks of different lengths in between each
adjacent parallel
spaced-apart bars) and processing speeds, meaning that a high efficiency end
matcher
1
CA 2986679 2017-11-24
(i.e. where one plank is placed in between each adjacent parallel spaced-apart
bars) will
have low processing speeds and vice-versa.
=
[0004] In another type of well-known end matchers, the Plank Feeder consists
in feeding
planks to the end matcher through the use of an inclined chute and trap-door
positioned
above the end matcher; in such systems, the planks to slide down towards the
trap-door
and the trap-door opens up at the right moment so one plank at a time is
deposited in
between the moving parallel spaced-apart bars. There is a certain limit to the
speed at
which such Plank Feeder can operate, to ensure that the planks actually slide
down the
inclined part and are dropped in between the spaced-apart bars.
[0005] In cases where the spaced-apart bars move (and the speed at which the
whole
end matcher can operate) faster than the Plank Feeder can feed the planks,
manual
operators are positioned nearby and manually place planks in between spaced-
apart bars
which did not receive a plank from the Plank Feeder. However, the introduction
of manual
operations in a manufacturing process is not optimal in terms of efficiency.
The
introduction of extra Plank Feeders is also not optimal as it leads to
hardwood
manufacturing machines with increased footprint.
[0006] There is therefore an ongoing need for higher efficiency (where the
majority of
adjacent parallel spaced-apart bars contains a plank) higher processing speeds
end
matchers, more specifically for Plank Feeder that can deposit planks, at high
processing
speeds, in between the majority of moving parallel spaced-apart bars of end
matchers.
SUMMARY
[0007] In one aspect, there is provided a wood plank feeder for transferring
wood plank
from a conveyor to transversely moving parallel spaced-apart bars and wherein
the wood
plank exits the conveyor in a direction substantially parallel to the spaced-
apart bars, the
wood plank feeder comprising: a pair of rollers positioned downstream of the
conveyor,
at least one of the two rollers being rotationally driven by a power source,
and a support
positioned downstream of the pair of rollers and over the transversely moving
parallel
2
CA 2986679 2017-11-24
spaced-apart bars; wherein the wood plank flowing through the pair of rollers
is directed
over the support.
[0008] The wood plank feeder may comprise a plank position sensor for
detecting a
presence of a trailing edge extremity of the wood plank in between the pair of
rollers, the
plank position sensor being operationally linked to the at least one of the
two rollers being
rotationally driven by a power source at a rotational speed. The plank
position sensor
may cause the at least one of the two rollers being rotationally driven by a
power source
to reduce its rotational speed when the presence of a trailing edge extremity
of the wood
plank in between the pair of rollers is detected.
[0009] The pair of rollers may be moveable with respect to one another.
[0010] The at least one of the two rollers being rotationally driven by a
power source may
comprise a wood gripping surface and the pair of rollers may be subjected to a
biasing
force acting against a movement of the pair of rollers away from one another.
[0011] The wood plank feeder may comprise a bar gap sensor for detecting a
position of
at least one of the parallel spaced-apart bars vertically below the support,
the bar gap
sensor being operationally linked to the at least one of the two rollers being
rotationally
driven by a power source. When the presence of a trailing edge extremity of
the wood
plank in between the pair of rollers is detected, the bar gap sensor may cause
the at least
one of the two rollers being rotationally driven by a power source to stop
rotating when
an unsatisfactory position of the at least one of the parallel spaced-apart
bars vertically
below the support is detected and then to resume rotating when a satisfactory
position of
the at least one of the parallel spaced-apart bars vertically below the
support is detected.
[0012] The wood plank feeder may comprise a bar gap sensor for detecting a
position of
at least one of the parallel spaced-apart bars vertically below the support,
the bar gap
sensor being operationally linked to the support. When the presence of a
trailing edge
extremity of the wood plank in between the pair of rollers is detected, the
bar gap sensor
may cause the support to be removed from underneath the wood plank when a
3
CA 2986679 2017-11-24
satisfactory position of the at least one of the parallel spaced-apart bars
vertically below
the support is detected.
[0013] The wood plank feeder may comprise a bar gap sensor for detecting a
position of
at least one of the parallel spaced-apart bars vertically below the support,
the bar gap
sensor being operationally linked to the at least one of the two rollers being
rotationally
driven by a power source and being operationally linked to the support. When
the
presence of a trailing edge extremity of the wood plank in between the pair of
rollers is
detected, the bar gap sensor may cause the at least one of the two rollers
being
rotationally driven by a power source to stop rotating when an unsatisfactory
position of
the at least one of the parallel spaced-apart bars vertically below the
support is detected
and, when a satisfactory position of the at least one of the parallel spaced-
apart bars
vertically below the support is detected, to cause the at least one of the two
rollers being
rotationally driven by a power source to resume rotating and to cause the
support to be
removed from underneath the wood plank.
[0014] The support may be a horizontally displaceable plate. The bar gap
sensor may
cause the horizontally displaceable plate to be removed from underneath the
wood plank
when a satisfactory position of the at least one of the parallel spaced-apart
bars vertically
below the horizontally displaceable plate is detected, after a presence of a
trailing edge
extremity of the wood plank in between the pair of rollers has been detected.
[0015] The bar gap sensor, when a unsatisfactory position of the at least one
of the
parallel spaced-apart bars vertically below the horizontally displaceable
plate is detected,
may cause the at least one of the two rollers being rotationally driven by a
power source
to stop rotating and, when a satisfactory position of the at least one of the
parallel spaced-
apart bars vertically below the horizontally displaceable plate is detected,
to cause the at
least one of the two rollers being rotationally driven by a power source to
resume rotating
and to cause the horizontally displaceable plate to be removed from underneath
the wood
plank.
[0016] In another aspect, there is provided a method for transferring wood
plank from a
conveyor to transversely moving parallel spaced-apart bars, the method
comprising:
4
CA 2986679 2017-11-24
causing a movement of the wood plank from the conveyor, in a direction
substantially
parallel to the spaced-apart bars, over such moving parallel spaced-apart bars
at a
determined translational speed; when the wood plank has reached a determined
position
over the moving parallel spaced-apart bars, reducing the determined
translational speed
of the wood plank; determining a position of at least one of the moving
parallel spaced-
apart bars below the plank; and performing only one of the following 2 steps:
if the at least one moving parallel spaced-apart bars is in an unsatisfactory
position, reducing the determined translational speed of the wood plank to
zero
and holding such wood plank in a stationary position until the at least one
parallel
spaced-apart bar is in a satisfactory position, then, when the at least one
moving
parallel spaced-apart bars is in a satisfactory position, resuming the
movement of
the wood plank and letting such wood plank fall between 2 transversely moving
parallel spaced-apart bars;
if the at least one moving parallel spaced-apart is in a satisfactory
position, letting
the wood plank fall between 2 transversely moving parallel spaced-apart bars.
[0017] The step of causing a movement of the wood plank from the conveyor may
be
performed by pinching the wood plank between two rollers, at least one of the
two rollers
being rotationally driven by a motor.
[0018] The determined position of the wood plank may be reached when a
trailing edge
extremity of such wood plank is located between the two rollers.
[0019] The satisfactory position of the moving parallel spaced-apart bars may
be when
a gap between adjacent moving parallel spaced-apart bars is positioned such
that letting
the wood plank, held over the moving parallel spaced-apart bars, will result
in such wood
plank falling between such adjacent moving parallel spaced-apart bars.
[0020] Further details of these and other aspects of the subject matter of
this application
will be apparent from the detailed description and drawings included below.
CA 2986679 2017-11-24
DESCRIPTION OF THE DRAWINGS
[0021] Reference is now made to the accompanying figures in which:
[0022] Fig. 1 is a schematic isometric view of a hardwood manufacturing
machine
comprising a linear conveyor and an end matcher pursuant to an embodiment of
the
invention;
[0023] Fig. 2 is an isometric view of the plank feeder of the hardwood
manufacturing
machine of Fig. 1;
[0024] Figs. 3-6 are cross-sectional view of the plank feeder of Fig. 2 in
operation,
showing a wood plank being processed through the plank feeder; and
[0025] Fig. 7 is an isometric view of the linear conveyor of the hardwood
manufacturing
machine of Fig. 1.
DETAILED DESCRIPTION
[0026] Fig. 1 illustrates a downstream portion of a hardwood manufacturing
apparatus,
more specifically the portion where hardwood planks 3, having a thickness T, a
length L
and a width W, exiting moulder machines (the details of which are not shown)
are carried,
sequentially one after another, in a direction D1, by a linear conveyor 1 to
an end matcher
2 and where, in turn, end matcher 2 carries hardwood planks 3 in a direction
D2 for further
processing Indeed, as is well known in the art, hardwood planks 3 exiting
moulder
machines need to have their ends further detailed. This is done by end matcher
2 which
includes parallel spaced-apart bars 21, transversely moving over a combination
of fixed
surfaces 22 and side-shift rollers 23, 24 and 25 (the spaced-apart bars 21
moving
hardwood planks 3 in direction D2 and side-shift rollers 23, 24 and 25 moving
hardwood
planks 3 within spaced-apart bars 21 in respective directions D3, D4 and D5)
and end-
cutters 26 and 27 positioned at lateral ends of end matcher 2 (for performing
the needed
detailing). Planks 3 carried in direction D2 (by moving parallel spaced-apart
bars 21)
therefore are moved (by side-shift roller 23) in direction D3 (so as to be
positioned to be
processed by end cutter 26), are then processed by end cutter 26, are then
moved (by
6
CA 2986679 2017-11-24
side-shift roller 24) in direction D4 (so as to be positioned to be processed
by end cutter
27), are then processed by end cutter 27, are then moved (by side-shift roller
25) in
direction 05 and then carried downstream and out of end matcher 2. For proper
functioning of end matcher 2, no more than one plank 3 can be positioned
between
adjacent parallel spaced-apart bars 21. The deposit of plank 3 between
adjacent parallel
spaced-apart bars 21 is accomplished by the plank feeder 4.
[0027] Fig. 2 illustrates in more details the upstream portion of end matcher
2, including
the plank feeder 4 which takes the planks 3 from linear conveyor 1 and
deposits them,
one at a time, in between moving parallel spaced-apart bars 21. The plank
feeder portion
comprises a support 41, a pinch roller 42 and a driving roller 43. Linear
conveyor 1 has
a carrying surface 11 to transport planks 3 to the plank feeder portion, more
specifically
to rollers 42 and 43. Driving roller 43 is positioned and dimensioned to
assist in the
continuous movement of plank 3 (in direction D1) and to assist in the pinching
function of
pinch roller 42; it is understood that any pinching elements, which do not
hinder the
continuous movement of plank 3, are possible pursuant to the invention. Pinch
roller 42
is positioned and dimensioned to pinch plank 3 (in conjunction with driving
roller 43) and
to move plank 3 in direction D1 over support 41; pinch roller 42 is also known
as an idle
roller has it is not driven by a motor, but simply allowed to rotate freely.
With the
assistance of a motor (not shown) however, driving roller 43 is driven at
variable desired
rotating speeds. Support 41, which receives plank 3 from rollers 42, 43, is
positioned
directly above end matcher 2; it is understood that any supporting element,
which can
support plank 3 and release it (as will be explained in more details below),
is possible
pursuant to the invention. The operation of the plank feeder portion, more
specifically of
support 41, pinch roller 42 and driving roller 43, is explained in more
details as follows,
with reference to Figs. 3-6.
[0028] Plank 3 is carried towards rollers 42, 43 by linear conveyor 1 in
direction D1 as
shown in Fig. 3 (for ease of understanding in Figs. 3-6, direction arrow A
represents the
direction of movement of conveying surface 11 and direction arrow B represents
the
direction of movement of plank 3). When plank 3 reaches rollers 42, 43, it is
pinched
between such rollers 42, 43. In the current embodiment, driving roller 43 is
vertically
7
CA 2986679 2017-11-24
aligned with conveying surface 11 and is rotationally driven by a motor (not
shown) and
functions as the driving force to urge plank 3 towards support. Pinch roller
42, on the
other hand, rotates freely so as to support and assist in the movement of
plank 3. When
no plank 3 is positioned between rollers 42, 43, the rotating surface of pinch
roller 42 is
located at a distance S from the rotating surface of driving roller 43 that
does not exceed
the anticipated thickness T of plank 3 and is preferably less than such
thickness T. When
plank 3 passes in between rollers 42, 43 such distance S is allowed to
increase and a
biasing force, pushing against the movement of pinch roller 42 and driving
roller 43 away
from one another, is applied. In combination with a gripping material present
on driving
roller 43, the biasing force pinches plank 3; consequently, the pair of
rollers 42, 43 drive
plank 3 towards support 41 (Fig. 4). In the current embodiment, driving roller
43, with a
rotating surface made of wood gripping material, is not allowed to move
vertically (i.e. no
vertical freedom of movement) and pinching roller 42 is allowed to move
vertically upward
(i.e. has vertical freedom of movement) against a biasing force (which pushes
pinching
roller 42 back down); it is however understood that other combinations of
rollers 42, 43,
gripping surfaces, freedoms of movement and biasing forces, which accomplish
the
function of driving plank 3 from linear conveyor 1 to support 41, are possible
pursuant to
the invention. For example, without being limiting, rollers 42, 43 may both be
driven by
a motor and may both have gripping surfaces; in another non limiting example,
the motor
driven roller with a gripping surface may be the top roller, whereas the idle
pinch roller
may be the bottom roller.
[0029] As indicated above, support 41 is positioned over end matcher 2, more
specifically
over moving parallel spaced-apart bars 21. Top surface 41a of support 41 is
positioned
substantially parallel (horizontally) to conveying surface 11 and its vertical
position does
not exceed the vertical position of such conveying surface 11 and of driving
roller 42;
consequently, plank 3, driven by rollers 42, 43 moves over support 41 and
slides over
top surface 41a. Rollers 42, 43 move plank 3 over support 41 until trailing
edge extremity
31 of plank 3 is positioned (and still pinched) between such rollers 42, 43;
the rotational
movement of rollers 42, 43 is then reduced (and may even be stopped as will be
explained in more details below) such that plank 3 is supported at one end
(trailing edge
extremity 31) by rollers 42, 43 and at the other end (leading edge extremity
32) by support
8
CA 2986679 2017-11-24
41 (Fig. 5). Preferably, support 41 is sufficiently wide to support leading
edge extremity
32 of any plank 3. It is however possible, pursuant to the invention, to have
shorter
supports 41 so long as the supporting function of plank 3 (in conjunction with
rollers 42,
43) is achieved.
[0030] It is to be noted that, the higher the speed at which plank 3 is driven
by rollers 42,
43, the more efficient plank feeder 4 will be; indeed, the faster plank 3 can
be positioned
over support 41 and on top surface 41a (as shown in Fig. 5), the sooner such
plank 3 can
be dropped between adjacent parallel spaced-apart bars 21 moving vertically
below such
support 41. At a minimum, rollers 42, 43 are able to carry plank 3 towards
support 41 at
higher speeds than the speeds at which linear conveyor 1 carry plank 3. A
plank position
sensor 45 is positioned immediately upstream of rollers 42, 43 to detect the
presence of
plank 3. In the current embodiment, because plank 3 accelerates once it is
pinched (and
driven) by rollers 42, 43, a gap arises between sequential planks 3 being
carried by linear
conveyor 1, such that when plank position sensor 45 detects a gap, it means
that trailing
edge extremity 31 of plank 3 is positioned between such rollers 42, 43. It is
understood
that other means of determining when trailing edge extremity 31 of plank 3 is
positioned
(and still pinched) between such rollers 42, 43 are possible pursuant to the
invention.
[0031] Once plank 3 is correctly positioned over the spaced-apart bars 21
moving
vertically below (i.e trailing edge extremity 31 of plank 3 is held in between
rollers 42, 43
and leading edge extremity 32 of plank 3 is held by top surface 41A of support
41, as
shown in Fig. 5), a determination is made as to whether the time is right to
drop plank 3
between adjacent parallel spaced-apart bars 21 moving below; in the current
embodiment, this is accomplished via a bar gap sensor (not shown) which is
able to
determine if a gap between 2 adjacent parallel spaced-apart bars 211s located
below
support 41 such that, if support 41 is removed, plank 3 will fall and position
itself properly
in between such bars 21. If the time is not right (i.e. the gap sensor
determines that the
space-apart bars below are in an unsatisfactory position), the rotational
movement of
rollers 42, 43 is stopped (so as to stop the translational movement of plank
3) until a well-
positioned gap between 2 adjacent parallel spaced-apart bars 21 is detected
(i.e. the gap
sensor determines that the space-apart bars below are in a satisfactory
position). When
9
CA 2986679 2017-11-24
this occurs, the bar gap sensor (not shown) sends a start signal to rollers
42, 43 (so that
translational movement of plank 3 in direction D1 resumes) and an activation
signal to
support 41 (so that top surface 41a is removed from under plank 3, thereby
allowing plank
3 to fall under its own weight); as a result, plank 3 is dropped between 2
adjacent parallel
spaced-apart bars 21 and plank 3 can be further processed by end matcher 2
(Fig. 6). It
is to be noted that, the higher the speed at which support 41 is removed from
under plank
3 (more specifically top surface 41sa is removed from under plank 3), the more
efficient
plank feeder 4 will be (as the sooner such plank 3 can be dropped between
adjacent
parallel spaced-apart bars 21 moving vertically below such support 41). In the
current
embodiment, rollers 42, 43 are re-activated to push plank 3 in direction D1
before support
41 is removed from under plank 3 to ensure the correct placement plank 3 in
between
adjacent parallel spaced-apart bars 21.
[0032] It is understood that if, at the moment plank 3 is correctly positioned
over the
spaced-apart bars 21 moving vertically below (i.e. trailing edge extremity 31
of plank 3 is
held in between rollers 42, 43 and leading edge extremity 32 of plank 3 is
held by top
surface 41A of support 41, as shown in Fig. 5), a determination is made that
the time is
right to drop plank 3 between adjacent parallel spaced-apart bars 21 moving
below (i.e.
the gap sensor determines that the space-apart bars below are in a
satisfactory position),
the rotational movement of rollers 42, 43 does not need to be stopped; its
rotational speed
is simply reduced to a speed that will ensure that plank 3 is not propelled
horizontally
over and beyond end matcher 2 and top surface 41a is removed from under plank
3,
thereby allowing plank 3 to fall under its own weight in between 2 adjacent
parallel
spaced-apart bars 21.
[0033] It should be noted that if it is determined that, when plank 3 is
correctly positioned
over the spaced-apart bars 21 moving vertically below (i.e. trailing edge
extremity 31 of
plank 3 is held in between rollers 42, 43 and leading edge extremity 32 of
plank 3 is held
by top surface 41A of support 41, as shown in Fig. 5), the time is right to
drop plank 3
between adjacent parallel spaced-apart bars 21 moving below, the rotational
movement
of rollers 42, 43 does not have to be stopped (i.e. the translational movement
of plank 3
does not have to be stopped) and support 41 can be removed from under plank 3.
In
CA 2986679 2017-11-24
such instance, the rotational movement of rollers 42, 43 may have to be slowed
down to
ensure that plank 3 is not propelled horizontally over and beyond end matcher
2.
[0034] It should be noted that, in circumstances when the translational
movement of
plank 3 is stopped, it must be ensured that planks further upstream being
carried by
conveying surface 11 do not collide with trailing edge extremity 31 held in
between rollers
42, 43. In most circumstances, there will be enough space with the upstream
planks that
no collision will occur; in certain circumstances, there might be a need to
stop the
upstream plank from travelling towards plank 3 (stopped between rollers 42,
43). In the
current embodiment, this is addressed by stationary plate 48, located between
linear
conveyor 1 and rollers 42, 43, over which plank 3 is allowed to slide, and a
pneumatic
brake that can be activated (when need be) to pin down (and stop) a plank from
progressing further over such plate 48. It is however understood that there
are other
ways to stop the translational movement of upstream planks towards rollers 42,
43 when
need be.
[0035] Reference is made again to Figs. 3-6 to explain more generally the
operation of
the current embodiment. Linear conveyor 1 carries planks 3 on a moving
conveying
surface 1 (typically a belt) length-wise in single files (i.e. one after
another) at speeds
exceeding the speeds at which planks exit moulder machine i.e. at speeds
exceeding
about 200-350 ft/min (typical speeds at which planks exit moulder machine); in
the current
embodiment, linear conveyor 1 operates at about 600 ft/min. It has been found
that the
transfer step between linear conveyor 1 and end matcher 2 (i.e. the process by
which
plank 3 moves from linear conveyor 1 to end matcher 2) is where increases in
efficiency
can be found. In the current embodiment, planks 3 exits linear conveyor 1 in a
direction
D1 substantially perpendicular to the movement direction D2 of the parallel
spaced-apart
bars 21 of end matcher 2 i.e. substantially parallel to the parallel spaced-
apart bars 21.
When leading edge extremity 32 of plank 3 reaches rollers 42, 43, it's linear
speed is
increased to approximately 800 ft/min, so as to bring it as fast as possible
in position over
the parallel spaced-apart bars 21 of end matcher 2 (in the embodiment shown in
Fig. 3,
driving roller 43, with its gripping surface, in combination with pinch roller
42,
accomplishes this). As outlined above, to prevent plank 3 from prematurely
falling down
11
CA 2986679 2017-11-24
in end matcher 2, plank 3 is slid over plate 41, more specifically over top
surface 41A, so
that plank 3 is held over parallel spaced-apart bars 21 moving below. The time
it takes
rollers 42, 43 to place plank 3 in position over parallel spaced-apart bars 21
depends on
its length; as length L of plank 3 varies from 10" to 96", the length of time
it takes will vary.
When trailing edge extremity 31 of plank 3 reaches rollers 42, 43, such
rollers are stopped
if the gap sensor (not shown) detects that it is not the proper time to let
such plank 3 fall
below; in conjunction with plate 41, plank 3 is therefore held stationary over
parallel
spaced-apart bars 21 moving below. As soon as a proper positioning of parallel
spaced-
apart bars 21 moving below is detected, rollers 42, 43 are re-activated and
plate 41 is
removed so as to allow plank 41 to fall in between two adjacent spaced-apart
bars (as
outlined above, it is understood that rollers 42, 43 may not need to be
stopped if proper
positioning of parallel spaced-apart bars 21 moving below is detected at the
moment
trailing edge extremity 31 of plank 3 reaches rollers 42, 43). In terms of
parts/minute,
taking into account the time it takes the planks 3 to fall from plate 41 in
between parallel
spaced-apart bars 21, it means that plank feeder 4 can process about 80-180
parts/minutes (variations account for fact that planks 3 can be anywhere
between 10"
and 96" in length) towards end matcher 2; this rates favourably against prior
art plank
feeders which typically cannot process more than 90 parts/minutes. As current
end
matchers 2 can process up to 180 parts/minutes, the resulting increase in ppm
that the
current embodiment of the plank feeder provides is useful. It must be noted
that the
previous ft/min and parts/min numbers are provided solely for exemplary
purposes and
should not be construed in any way as limiting the invention.
[0036] As can be understood from the description above, the efficiency of
plank feeder
4 will depend on the translational speed at which rollers 42. 43 can position
plank 3 over
support 41. The efficiency of plank feeder 41 will also depend on the speed at
which
support 41 can be removed from under plank 3 and the height plank 3 has to
travel before
hitting end matcher 2; the closer top surface 41A is located over end-matcher
2 and the
quicker support 41 can be removed, the more efficient plank feeder 4 will be.
In the
current embodiment, support 41 is a single thin plate that can be slid
horizontally between
a support and a non-support position. It has been found that this is an
efficient set-up as
such single thin plate can be positioned closer over end matcher 2 and can
activated
12
CA 2986679 2017-11-24
quicker than already known trap-door set-ups. It is however possible, pursuant
to the
invention, to have other types of support 41.
[0037] Fig. 7 is an exemplary illustration of linear conveyor 1 conveying
hardwood planks
3 towards plank feeder 4, more specifically towards rollers 42, 43. Only side
wall 15,
near which planks 3 are carried by conveying surface 11, is shown; the
opposite side wall
(not shown) is similar except for the fact that it can be moved towards/away
side wall 15
so as to create a funnelling path forcing planks 3 towards side wall 15 as it
is being carried
by conveying surface 11 towards rollers 42, 43. Linear conveyor 1 may contain
a
pressure wheel 13 which exerts a downward pressure on wood plank 3 to locally
increase
the friction force between such plank 3 and conveying surface 11. Linear
conveyor 1
may also contain a plank feed detecting wheel 12 for detecting relevant
information about
the planks 3 upstream of plank feeder 4 being carried by conveying surface 11.
[0038] The above description is meant to be exemplary only, and one skilled in
the art
will recognize that changes may be made to the embodiments described without
departing from the scope of the invention disclosed. Still other modifications
which fall
within the scope of the present invention will be apparent to those skilled in
the art, in
light of a review of this disclosure, and such modifications are intended to
fall within the
appended claims.
13
CA 2986679 2017-11-24
