Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1
GLUING DEVICE FOR VENEER SHEET STACKS
FIELD OF THE INVENTION
The present invention relates to a device fox
applying a coating of glue on two longitudinal edges of
elongated veneer sheet stacks.
2
In the prior art, the gluing is usually done
manually with a paint brush or with a spray gun applicator.
However, the layer of glue is not always uniform and
problems might occur in the splicer because of a local
surplus of glue. Additionally, the spraying of glue can be
very hazardous for the health of the workers.
SUMMARY OF THE INVENTION
The object of the present invention is to provide
a device for applying a very uniform layer of glue on a
veneer sheet stack.
More particularly, the object of the present
invention is to provide a device for applying a coating of
glue on two longitudinal edges of elongated veneer sheet
stacks, the device comprising:
a supporting surface;
first pressing means for applying a force on the
longitudinal edges of a stack, thereby urging them to be
substantially perpendicular to a first plane surface of the
stack:
second pressing means far applying an offset force over
a second plane surface of the stack, the second plane
surface being opposite the first plane surface;
driving means for longitudinally advancing the stack
over the supporting surface;
two sets of glue distributing rollers adjacent a
corresponding longitudinal edge of the stack, at least one
set being movable laterally, each set comprising:
- an engraved roller for engagement with its
corresponding edge of the stack: and
- a substantially smooth roller juxtaposed to the
engraved roller for wiping off excesses of glue
thereon; and
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means for providing a substantially liquid glue on the
engraved roller of each set of glue distributing rollers.
According to a preferred embodiment, the
supporting surface co~pprises a plurality of evenly spaced
apart horizontal rollers.
According to another preferred embodiment, the
first pressing means comprise two opposite lateral roller
assemblies, each located on a corresponding edge of the
device and provided with a plurality of spaced apart
1o vertical rollers, at least one lateral roller assembly being
movable laterally.
According to a still preferred embodiment, the
second pressing means comprise a horizontal wheel assembly
provided with a plurality of substantially aligned wheels
for engagement with said second plane surface.
According to a still preferred embodiment, the
driving means comprise a motor mechanically connected to at
least one of the horizontal rollers for driving the same
into rotation.
According to a still preferred embodiment, the
engraved roller and the substantially smooth roller of each
set of glue distributing rollers are rotated at a speed
synchronized with an advancing speed of the stack, the
substantially smooth roller of each set being rotated in
opposition to the engraved roller.
According to a still preferred embodiment, the
engraved roller has a thread-like groove over the surface
thereof .
According to a still preferred embodiment, the
megns for providing glue comprise a tube circuit having ends
located at a top part between the engraved roller alnd the
substantially smooth roller of a corresponding set of glue '
distributing rollers.
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4
According to a still preferred embodiment, the
device further comprises a pan located under the set of glue
distribution rollers for collecting surplus of glue.
It is also an object of the present invention to
provide a device for applying a coating of glue on two
longitudinal edges of elongated veneer sheet stacks, the
device comprising:
a plurality of evenly spaced apart rollers;
first pressing means for applying a force on the
longitudinal edges of a stack, thereby urging them to be
substantially perpendicular to a first plane surface of the
stack, the first pressing means comprising two opposite
lateral roller assemblies, each located on a corresponding
edge of the device and provided with a plurality of spaced
apart vertical rollers, at least one lateral roller assembly
being movable laterally;
second pressing means for applying an offset force over
a second plane surface of the stack, the second plane
surface being opposite the first plane surface, the second
pressing means comprising a horizontal wheel assembly
provided with a plurality of substantially aligned wheels
for engagement with said second plane surface;
driving means for longitudinally advancing the stack
over the horizontal rollers, the driving means comprising a
motor mechanically connected to at least one of the
horizontal rollers for driving the same into rotation;
two sets of glue distributing rollers, at least one set
being movable laterally, each set being positionable to be
adjacent to a corresponding edge of the stack and comprising
an engraved-roller having a thread-like groove over the
surface thereof for engagement With a corresponding edge of
the stack and a substantially smooth roller laterally
juxtaposed to the engraved roller for wiping off excesses of
glue thereon, the engraved rollers and the substantially
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smooth rollers being rotated at a speed synchronized with an
advancing speed of the stack, the substantially smooth
rollers being rotated in opposition to their corresponding
engraved roller; and
5 means for providing a substantially liquid glue on the
engraved rollers, the means comprising two distribution
tubes, each located at a top part between the engraved
roller and the substantially smooth roller of a
corresponding set of glue distributing rollers.
A non restrictive description of a preferred
embodiment will now be given with reference to the appended
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view df the gluing device
according to an embodiment of the present invention, shown
here without the upper roller assemblies;
FIG. 2 is a front view similar to FIG. 1, with the
edges of a stack being currently glued;
FIG. 3 is a edge elevational view of the gluing
device of FIG. 1;
FIG. 4 is a cross-sectional view of the device
according to line IV-IV of FIG. 3:
FIG. 5 is a schematic view of a stack being
pressed laterally and downwardly.
DESCRIPTION OF A PREFERRED EMBODIMENT
Referring to FIGS. 1 to 3, the gluing device 20
comprises a rigid main frame 21 having a feeding section 23
and a gluing section 25. The device 20 has a supporting
surface for supporting the weight of the stack l0.
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Each stack 10 comprises a plurality of elongated
veneer sheets having substantially the same size, especially
the same width.
This supporting surface preferably consists of a
plurality of spaced apart horizontal rollers 22 allowing the
stack 10 to be supported and to be moved longitudinally in
the device 20 from the entry to the exit thereof. The
rollers 22 are operatively attached to the edge rails 24 and
driven by driving means which may comprise an electrical
motor 26 mechanically connected to the end rollers by a
chain or belt 28. Each roller 22 is connected to an adjacent
roller 22 by means of belts connected to a main shaft (not
shown). The supporting surface may also be a conveyor (not
shown), a plurality of small wheels (not shown) or any other ..
similar system.
The glue application is achieved by two sets of
rollers 50, each comprising a roller 52 and a roller 54,
both rotating around a vertical pivot axis. Each set 50 is
adjacently located to a corresponding longitudinal edge of
the stack 10. The rollers 52 are engraved rollers having
preferably a thread-like groove over the surface thereof,
and the rollers 54 are substantially smooth rollers
laterally juxtaposed to a corresponding engraved roller 52.
The rollers 52 and 54 are preferably supported by
a support 55 and are rotated, at a speed synchronized with
the advancing speed of the stack 10, by means of an
electrical motor 56 mechanically connected thereon. The
substantially smooth roller 54 of each pair 50 is rotated in
opposition to the corresponding engraved roller 52.
The purpose of the engraved roller 52 is to
directly apply the glue which is a substantially liquid glue
provided by suitable means, preferably comprising a pump 60
taking glue from a tank (not shown) and circulating it
through the device 20 by means of a tube circuit 61 having
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ends 62 located in the middle upper gap of each set of
rollers 50, as shown in FIGS. 1 and 2. As shown in FIG. 2,
the glue sticks to the engraved rollers 52 and is
distributed on the longitudinal edges of the advancing stack
10. As the glue is poured between the rollers 52 and 54, it
slowly falls down under gravity and tends to accumulate at
the lower portion of the engraved rollers 52. The
substantially smooth rollers 54 help keeping a constant
thickness of glue on their corresponding engraved roller 52
by counter-rotating at a given distance therefrom. The
surplus of glue falling from the bottom of the rollers 52
and 54 goes to a funnel-like pan 70 where the glue may be
accumulated and then recirculated through the pump 60.
At least one set of rollers 50 is movable along
slides 51 laterally for adjusting the distances between the
two sets of rollers 50 to the width of the stack 10. The
movement of the movable set of rollers 50 relies on the
position of a movable lateral roller assembly 30 described
hereinafter. Preferably, an endless screw 10o driven by an
electrical step motor 102 mechanically connected thereto by .
means of a chain or a timing belt 101 allows the movement of
the movable set of rollers 50.
Referring to FIG. 3, the stack 1o first enters the
device 20 by the entry table 23. The stack 10 is loaded in
the device 20 either by hand or by an automatic loading
machine (not shown).
Referring to FIGS. 3 to 5, first pressing means
are used for applying a force on both longitudinal edges 12
of the stack 10 for urging them to be substantially
perpendicular to a first plane surface thereof. These
longitudinal. edges 12, being vertical in the preferred
embodiment, have to be substantially. perpendicular to the
supporting surface defined by the first plane overlying the
rollers 22 so that the glue can be applied very uniformly
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thereon. The first plane substantially coincides with the
bottom veneer sheet of the stack 10 since it rests on the
supporting surface.
In the preferred embodiment, the first pressing
means comprise two opposite lateral roller assemblies 30,
each located on a corresponding edge of the device 20 and
provided with a plurality of spaced apart vertical rollers
32. Since the width of the stacks 10 may be different from
one to the other, and for easying the loading of the stacks
10, at least one roller assembly 30 is movable laterally.
Referring to FIG. 4, this may be achieved by means of at
least one pneumatic cable actuator 34 moving the, movable
roller assembly 30 along a rail 36. An optical switch (not
shown) may be used for stopping the movable roller assembly
30 at the right place before it crushes the veneer stack lo.
When the stack 10 is loaded, the distance between
the two lateral roller assemblies 30 is maximum in order
that enough room is created for the insertion of the stack
l0. Once the stack 10 is on the supporting surface, the
actuator 34 is operated by an optical switch for moving the
stack 10 against the other lateral roller assembly 30 and
for applying the lateral force. The force will then be
applied on both edges because of the resultant force of the
other lateral roller assembly 30.
second pressing means are provided for applying a
downward offset force over the stack 10. In the preferred
embodiment, this offset force is applied downwardly by means
of a horizontal wheel assembly 40 provided with a plurality
of substantially aligned wheels 42. The horizontal wheel
assembly 40 may be moved up and down by means of pneumatic
actuators 44.
As schematically shown in FIG. 5, the purpose of
the horizontal wheel assembly 40 is to generate a small
deformation 46 of the stack 10 for allowing the lateral
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surplus of wood pushed inside by the vertical roller
assembly 30 to go somewhere during the alignment of the
sheets, and thus virtually unstress the excess of wood so as
to produce aligned and smooth edges of the stack 10.
Referring to fIG. 3, two upper roller assemblies
80 may also be provided for applying a pressure on the top
the stack 10 so that glue stays only on the longitudinal
edges 12 and does not go between the sheets. The upper
roller assemblies 80 comprise a plurality of rollers 81 and
are operatively connected to the frame 21 by means of
sliders 84 (partially shown) movable inside vertical beams
of the frame 21. Both upper roller assemblies 80 are
connected to each other by the sliders 84 and are moved up
and down by means of two pneumatic actuators 82. A rod 86
mechanically connected to both sliders 84 ensures that they
are both moved symmetrically together.
Once the stack 10 is at the exit of the device 20,
it may go to a conveyor ( not shown ) bringing the stack 10
near a veneer splicer (not shown).
Although a preferred embodiment of the invention
has been described in detail herein arid illustrated in the
accompanying drawings, it is to be understood that the
invention is not limited to this precise embodiment and that
various changes and modifications may be effected therein
without departing from the scope or spirit of the invention.
