Note: Descriptions are shown in the official language in which they were submitted.
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
METHOD AND APPARATUS FOR APPLYING GLUE TO BOXES
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for applying glue to
boxes, and
more particularly to a method and apparatus that is used for applying glue to
boxes during a
process of sealing the flaps of boxes.
BACKGROUND OF THE INVENTION
Cardboard boxes, cartons, and cases are widely used for holding many products,
including but not limited to powdered detergents, sugar, flour, and paclcaged
products. It is
especially important to achieve a good seal on boxes that contain powdered
materials and other
fine products, otherwise, these materials will leak from the boxes. That is,
these boxes should be
"sift proof '. In these boxes, or in boxes for other products, it may be
equally important for the
boxes to be sealed sufficiently to keep bugs and other pests from coming
inside the boxes. That
is, these boxes may also need to be infestation proof.
The process of making boxes generally involves folding and sealing the flaps
on the
boxes, such as with glue to fornz the box into a closed and sealed
configuration. Currently, boxes
are sealed with relatively complex and expensive glue guns. Often, the
applicators are stationary
devices (glue guns) that apply glue to moving carton flaps with a doctor
blade. The doctor blade
contains a series of narrow, rectangular channels that form orifices. The
orifices are arranged in
a line that is perpendicular to the direction of carton travel. As the carton
flaps move past the
glue gun, a series of valves open at various times to allow glue to be
extruded from the orifices.
Thin films of glue are then wiped or smeared onto the passing carton flaps to
fornz "U" or "II"-
shaped plan view patterns on the carton flaps that are used to seal the flaps
in a closed
configuration. Aside from the complexity and expense of this type of
apparatus, the narrow glue
channels in the doctor blades are easily clogged and require regular
maintenance. There is also
continuous dynamic contact between the carton flaps and a "wear bar" that
holds the flaps against
the glue guns and at a specific distance from the glue orifices. This requires
periodic adjustments
and eventual replacement of the wear bar and doctor blade assembly.
Italian Patent BO 94A 000,044 assigned to Senzani is directed to an apparatus
for tightly
securing the closing tabs of the ends of cases or boxes, by means of lines of
glue delivered partly
onto the tabs, with orientation transverse to the forward moving direction of
the boxes. The
apparatus described in this patent application suffers from a number of
drawbacles. A primary
1
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
drawback is the fact that the apparatus is driven by the same drive that
powers the boxing
machine. The boxing machine may not have sufficient power to drive such an
apparatus. This
patent teaches no way to phase the application of the glue onto the boxes
other than by tying the
movement of the glue application apparatus to the boxing machine.
European Patent Application EP 1 069 045 A1 assigned to Senzani is directed to
an
apparatus for supplying adhesive to dispensing heads. The apparatus described
in this patent
application also suffers from a number of drawbacks. A primary drawbaclc is
the complicated
nature of the apparatus, and the potential for leakage of the adhesive from
the flexible hose
connection and rotary hydraulic coupling shown therein.
LT.S. Patent 5,094,398 issued to Jeter, et al. (assigned to Nordson
Corporation) is directed
to an apparatus for adjusting the relative position of two or more material
dispensers.
Thus, there is a need to provide improved methods and apparatus for applying
glue to
boxes.
SUMMARY OF THE INVENTION
The present invention relates to a method and apparatus for applying glue to
boxes, and
more particularly to a method and apparatus that is used for applying glue to
boxes during a
process of sealing the flaps of boxes.
There are numerous, non-limiting embodiments of the invention. In one
embodiment, the
apparatus may comprise an independently powered, stand alone apparatus for
applying glue to
the flaps of boxes that is associated with a box-making assembly line or box
conveying line. The
apparatus may be driven independently from the mechanism that drives the box-
malting assembly
line or conveying line, yet phased to apply adhesive on the proper locations
on the box flaps. The
apparatus may comprise a moving mechanism that applies glue to the boxes as it
moves at an
angle to the direction the boxes are moving.
In the foregoing, or other embodiments, the method may comprise applying a
first line of
glue to the trailing flap of a first box and a second line of glue to the
leading flap of the second
box.
The apparatus may have a non-limiting number of other features that comprise
inventions
in their own right. Such features include, but are not limited to an improved
assembly for
conveying glue to the glue guns.
2
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
BRIEF DESCRIPTION OF THE DRAWINGS
While the specification concludes with claims particularly pointing out and
distinctly
claiming the invention, it is believed that the present invention will be
better understood from the
following description taken in conjunction with the accompanying drawings in
which:
Fig. 1 is a partially fragmented side view of one non-limiting embodiment of a
portion of
an assembly line for folding and sealing the flaps of boxes.
Fig. 2 is a plan view of a portion of the assembly line shown in Fig. 1.
Fig. 3 is a top view of one non-limiting embodiment of the apparatus for
applying glue to
the boxes.
Fig. 4 is a side view of the apparatus shown in Fig. 3.
Fig. 5 is an end view of the apparatus shown in Fig. 3.
Fig. 6 is a schematic plan view showing the how the glue pattern is formed on
a pair of
boxes.
Fig. 7 is a cross-sectional view of a line of adhesive talcen along line 7-7
of Fig. 6 that
shows an example of the flattened cross-sectional shape that some lines of
adhesive may have.
Fig. 8 is a cross-sectional view taken from the same perspective as Fig. 7,
that shows an
example of a beaded cross-sectional shape that other lines of adhesive may
have.
Fig. 9 is a schematic fragmentary side view of a box showing a final step in
the folding
and sealing of its flaps.
Fig. 10 is a schematic perspective view of a portion of the platform and rail
system of the
embodiment of the adhesive application apparatus shown in Figs. 3-5.
Fig. 11 is a side view of the assembly that supplies glue to the glue guns.
Fig. 12 is a plan view that shows the operating sequence of the apparatus on
two boxes.
3
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a method and apparatus for applying glue to
boxes, and
more particularly to a method and apparatus that is used for applying glue to
boxes during a
process of sealing the flaps of boxes.
There are numerous, non-limiting embodiments of the invention. Several non-
limiting
embodiments are described herein, as are several components of the apparatus,
each of which
may constitute an invention either in its own right or together with other
components. All
embodiments, even if they are only described as being "embodiments" of the
invention, are
intended to be non-limiting (that is, there may be other embodiments in
addition to these), unless
they are expressly described herein as limiting the scope of the invention.
The terms "boxes", "cartons" and "cases", as used herein, can all be
considered to be
synonymous for the purpose of the present invention. The terms "glue" and
"adhesive", as used
herein, will also be considered to be synonymous.
One non-limiting embodiment of an apparatus for carrying out the present
invention is
shown in Figs. 1-5. Figs. 1 and 2 show one non-limiting embodiment of a
portion of an assembly
line 10 for folding and sealing the flaps of boxes. The assembly line 10 for
folding and sealing
the flaps of boxes shown in Figs. 1 and 2 comprises a conveyor, which may be
in the form of a
continuous belt 12. The assembly line 10 may be used for not only folding and
sealing the flaps
of boxes, but also for filling the boxes with product(s). Therefore, the
assembly line 10 for
folding and sealing the flaps of boxes may be alternatively referred to as box-
making machine or
a carton-~Iling machine 10.
The box-making machine 10 may comprise a drive mechanism 14 and a filling
station 16.
The endless belt 12 travels around pulleys designated generally by reference
number 18, and
separately as pulley 18A and pulley 18B. The boxes 24 are traveling in the
direction of the arrow
designated "MD" (or in the "machine direction") in the box-making machine 10.
The boxes can
be provided to the box-malting machine 10 in a "knocked down flat" condition.
The box-malting
machine 10 can open the lrnocked down flat boxes into rectangular shapes.
As shown in Fig. 2, the box-making machine 10 may comprise more than one
(e.g., two)
adhesive application apparatuses 20. One apparatus can be used for sealing the
flaps on the
4
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
bottom of the box, and the other apparatus can be used for sealing the flaps
on the top of the box.
The two apparatuses 20 can be similar, or opposite hand copies of each other.
An opposite hand
copy of one of the apparatuses 20 can be inverted relative to the other to
apply adhesive on the
other side of the box. As shown in Fig. 2, the box-making machine can be
arranged in the form
of a conveyor that forms a loop when viewed from above, and one of the
apparatuses can be
located on one side of the loop, and the other apparatus can be located on the
other side of the
loop. In the embodiment shown in the drawings, after one side of the boxes are
sealed by the
adhesive application apparatus 20 shown in the lower portion of Fig. 2, the
boxes 24 travel to the
filling station 16 where the products) are placed in the boxes. The boxes then
move to the
adhesive application apparatus 20 shown in the upper portion of Fig. 2 where
the flaps on the
other side of the boxes are folded as sealed.
As shown in greater detail in Fig. 3, the adhesive application apparatus (or
simply
"apparatus") 20 comprises one or more glue guns designated generally by
reference number 22
that apply glue to boxes that are designated generally by reference number 24.
In this
embodiment, the glue guns apply glue to at least portions of the flaps 26 of
the boxes 24. Fig. 3
shows that the boxes 24 are traveling in the direction of the arrow designated
"MD" in the box-
making machine 10 that folds the flaps 26 and closes at least a portion of the
boxes 24.
In the embodiment shown in Figs. 3-5, there are three glue guns, 22A, 22B, and
22C. As
shown in Fig. 5, the glue guns 22 have nozzles 30, which have orifices 32. The
glue guns 22 may
be of any suitable type. However, in preferred embodiments, the glue guns 22
are of the "non-
contact" type. In other words, the glue guns 22 never make contact with the
surface to which the
glue is applied, such as the carton flaps 26. One example of such a glue gun
is referred to as the
E350 glue module available from Nordson Corporation of Duluth, Ga., USA. In
the apparatus
described herein, the glue guns 22 can be used in a truly non-contact manner,
with the nozzles 30
of the glue guns 22 spaced between as much as 1/a inch to 3/8 inch (6.4 mm to
9.5 mm) from the
portions of the box flaps 26 to which the adhesive is applied. (Of course, in
other less desirable
embodiments, contact glue guns can be used.) The glue guns 22 have an internal
valve that can
be operated mechanically, electrically, or pneumatically.
The boxes 24 and one example of the pattern of glue that can be applied to the
flaps 26
thereof, are shown schematically in Fig. 6. As shovcm in Fig. 6, in this
embodiment, the apparatus
applies glue to portions of the flaps of two boxes, box 24A and box 24B
simultaneously.
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
However, the apparatus and method described herein is not limited to
simultaneous application.
(It should also be understood that this is a non-limiting example, and in
other embodiments, the
apparatus 20 may apply glue to the flaps of a single box, rather than to
portions of the flaps of
two boxes during the process.) Box 24A will be referred to herein as a first
box, and box 24B
will be referred to as a second box. Each of the boxes 24A and 24B has a
leading side 34, a
trailing side 36, and two lateral sides 38 and 40.
The boxes 24 each have flaps 26 comprising a leading flap 42 and a trailing
flap 44
(which form a first pair of flaps that may be referred to as the "minor flaps"
in this embodiment),
located on opposite sides of the box adjacent the leading and trailing sides
of the box,
respectively, and a second pair of flaps, comprising flaps 46 and 48. Each
flap in the second pair
of flaps (which in this embodiment, may be referred to as the "major flaps")
is located adjacent to
one of the lateral sides 38 and 40 of the box on opposite sides of the box.
The boxes 24A and
24B can optionally be separated by a spacer, such as a spacing block 49. The
spacing block 49
has a centerline, CL.
In the embodiment shown in Fig. 6, the adhesive is applied in the general
pattern of an
upper case letter "U" on each box. This is shown on box 24B. The adhesive
pattern comprises a
leading line of adhesive 50, a trailing line of adhesive 52, and a third line
of adhesive 54. The
leading line of adhesive 50, the trailing line of adhesive 52, and the third
Iine of adhesive 54 may
be comiected, such as through the third line of adhesive 54 as shown in Fig.
6. In other
embodiments, they need not connect. In the embodiment shown in Fig. 6, the
lines of adhesive
may be rectilinear. In other embodiments, the lines of adhesive may be
rectilinear, curvilinear, or
have sections that are both rectilinear and curvilinear. The lines of adhesive
can be continuous,
intermittent, or they can have some portions that are continuous and some
portions that are
intermittent. The adhesive need not even be in the form of lines. For example,
a suitable
adhesive pattern can be formed of a plurality of spots of adhesive such as by
turning the glue
guns on and off. In these or other embodiments, there can be more than one
line or pattern of
adhesive on each flap. This might be useful, for example if the boxes have
handles, and a region
of adhesive needs to be applied on each side of the handle. More than one line
or pattern of
adhesive can be formed by multiple glue guns or by glue guns with a split
nozzle tip.
In the embodiment shown in Fig. 6, the leading and trailing lines of adhesive
50 and 52
have gaps 56 therein. Gaps 56 can be left for any suitable reason, such as to
avoid having the
6
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
adhesive come into contact with portions of the equipment that hold the flaps
folded. In this
embodiment, a gap is left for rail 64 that keeps the first pair of flaps
folded down so that glue can
be applied thereto. As shown in Fig. 3, a second rail 65 holds the second pair
of flaps in a folded
down configuration as well.
The lines of adhesive 50, 52, and S4 can be of any width and any cross-
sectional
configuration. Non-limiting examples of possible cross-sectional
configurations of lines of
adhesive are shown in Figs. 7 and 8, with the adhesive being designated by
reference number 58.
Fig. 7 shows an example of the flattened cross-sectional shape that some lines
of adhesive may
have. Fig. 8 shows an example of a raised or beaded cross-sectional shape that
other lines of
adhesive may have. The apparatus 20 may provide the lines of adhesive in
either cross-sectional
shape. However, in some embodiments, the beaded cross-sectional shape shown in
Fig. 8 is
preferred. Many prior apparatuses have been unable to form lines of adhesive
that are oriented
perpendicular to the machine direction (such as leading and trailing lines of
adhesive 50 and 52)
that have a beaded cross-section due to the fact that these apparatuses used
contact-type glue guns
or other types of applicators that needed to wipe or smear the adhesive on the
box flaps when
lines of adhesive are applied perpendicular to the machine direction.
The beaded cross-sectional configuration of the adhesive shown in Fig. 8 may
be
preferred for sealing the portion of the box shown in Fig. 9. There are
several reasons for this.
When the lines of adhesive have a raised cross-section (as opposed to a
flattened cross-sectional
configuration, such as that shown in Fig. 7), the adhesive can function more
like caulking in
filling gaps 60 such as those formed when the box flaps 26 are folded as shown
in Fig. 9. This
can provide the sealed box with better sift-proof and infestation proof
characteristics.
There are two periods of time that are of interest in sealing boxes with
heated adhesives.
The first period of time is the period that the adhesive remains sufficiently
molten that it is
capable of forming a bond with other portions of the box. This may be referred
to herein as the
"molten time" or "open time". After the molten time, the adhesive will harden
and the flap with
the adhesive thereon Will not be able to form a bond with other portions of
the box. The second
period of time is the period that the adhesive requires to bond with other
portions of the box.
This may be referred to herein as the "tack time" or the "green seal time".
Once the adhesive is
applied to the flap and the flap is brought into contact with the other
portion of the box to which
it is intended to be bonded, it is desirable that the adhesive set or "freeze"
as quicldy as possible.
7
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
If pressure is used to effect the bond, the faster the adhesive sets, the
shorter the amount of time
pressure is required to be applied to ensure that a seal is formed.
If the adhesive is heated, the raised cross-section of the adhesive also
allows the beaded
line of adhesive to retain heat better than a flattened line of adhesive due
to the smaller surface
area of exposed adhesive relative to the amount of adhesive in the line of
adhesive. This allows
the beaded line of adhesive to continue to remain taclcy, maintaining or
increasing the molten
time for the same, or a lesser amount of adhesive. Lesser amounts of adhesive
can also reduce
the tack time, and the length of time and/or amount of pressure that is
required to be applied on
the flaps 46 and 48 to keep the flaps folded until the adhesive "sets". The
use of the raised bead
of adhesive may allow the speed of the box-making line to be increased due to
the shorter tack
time. If desired, the speed of the box-malting line may even be decreased
because the adhesive
retains its heat longer, and the flaps do not have to be folded as quickly
after a heated adhesive is
applied. Thus, the method and apparatus described herein may reduce the amount
of adhesive
required and provide greater flexiblility in the operation of the box-making
machine.
The use of a raised bead of adhesive may also permit less expensive, lower
temperature
adhesives to be used since the heat will not dissipate from the raised line of
adhesive as rapidly as
it does from the flattened line of adhesive. In other embodiments, "cold" or
unheated types of
adhesive can be used. The use of the non-contact glue guns can also result in
a potentially
substantial savings in the amount of adhesive required, particularly with
respect to prior types of
apparatuses that extrude and wipe the adhesive. It has been found during the
operation of such
prior machines that the contact nature of the adhesive applicators, and the
wear on the same,
makes it continuously necessary to increase the amount of adhesive used in
such apparatuses over
time in order to achieve a good seal. The use of non-contact glue guns reduces
or eliminates this
problem.
The apparatus 20, and its operation will now be looked at in greater detail.
In the
embodiment of the apparatus 20 shown in Fig. 3, one or more of the glue guns
22, such as
stationary glue gun 22A, may be mounted in fixed positions and does not move
during the glue
application process. The stationary gun 22A is located so as to place a long
continuous bead of
glue onto the flaps that are parallel to the direction of carton travel and
(or the "machine
direction") at specific locations on the flaps. This line of glue forms the
third line of adhesive 54
which forms the "connecting bars" between the two legs of the "U" pattern
shown in Fig. 6. In a
8
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
preferred embodiment, this line of glue has a beaded cross-sectional
configuration such as that
shown in Fig. 8.
The other two glue guns, 22B and 22C, are dynamic (movable) and are used to
create the
leading and trailing lines of adhesive, 50 and 52, which form the two legs of
the glue patterns that
are perpendicular to the direction of carton travel. These guns 22B and 22C
are mounted on a
platform 62 that slides baclc and forth in the direction of the double-headed
arrow S on a bearing
rail 63. The entire assembly is shown in greater detail in Fig. 10. As shown
in Fig. 10, the
assembly comprising a beam 61, the bearing rail 63, and a linear bearing 67
that slides in the
direction of the arrow S. The platform 62 is mounted on the linear bearing 67.
As shown in Fig.
3, the bearing rail 63 is mounted in a position opposite the carton flaps and
at an angle to the
machine direction. In the embodiment shown in Fig. 3, the angle, A, is about
60°. In other
embodiments, the angle A can be any suitable angle, including angles greater
than about 45°.
In the embodiment shown in the drawings, hot glue is supplied to the glue guns
22
through an glue conveying assembly 80 that has a unique configuration. As
shown in Fig. 11, the
glue conveying assembly 80 comprises a glue supply 81 that supplies glue
through a conduit,
preferably a flexible conduit such as a flexible hose 82, that can be formed
in the configuration of
an arch. The hose 82 can be supported by a flexible support 84 that can be
made of plastic or
other suitable material. If desired, the hose 82 can be in more than one
section. The hose 82 may
be a heated hose, and can be obtained from Nordson Corporation. The hose 82
can be held onto
the support 84 in any suitable manner, including by several springs 86. The
hose 82 is preferably
arched so that it moves from a first position in which the radius of the apex
of the arch is smaller
to a flattened second position in which the radius of the apex of the arch is
larger. The arched
configuration may ensure that there are no sharp bends in the hose 82, and may
help eliminate or
reduce any movements that would rub or wear the hose 82.
The hose 82 can be formed into an arch that is in any suitable orientation. W
the
embodiment shown in the drawings, the hose 82 is arched over the path of
movement by the
dynamic glue guns 22B and 22C. In other embodiments, the orientation of the
arch of the hose
82 can be at any suitable angle relative to the path of movement of the glue
guns. In other
embodiments, the arch can be inverted, or in less preferred embodiments,
oriented in a sideways
orientation. The arched configuration of the hose 82 may provide a more simple
and reliable
9
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
mechanism than the assemblies used to supply glue in other devices, such as
the rotary hydraulic
coupling shown in European Patent application EP 1 069 045 Al.
In the embodiment shown, the platform 62 is connected to a crank arm 66 by
means of a
connecting rod 68. The crank arm 66 is mounted to the shaft 70 of a gearbox
72. The gearbox 72
can be driven by any suitable type of apparatus that can be used to generate
motion, or more
particularly, in this embodiment, since a crank arm is used, radial motion.
The apparatus in this
embodiment comprises a phasing mechanism that phases the application of glue
onto the box
flap. Preferably the phasing mechanism is a servo-controlled apparatus or
device (that is, a
feedback control system). In the embodiment shown, a servomotor 74 drives the
gearbox 72, and
because of the radial motion, the servomotor may constantly changes its speed.
Servomotors
have been used in robots previously. A suitable servomotor for the apparatus
shown in the
drawings is the Allen-Bradley H-4050-P-HOOAA servomotor available from
Rockwell
Automation of Milwaukee, Wisconsin, USA.
The movement of the glue guns 22B and 22C is, thus, not powered by the drive
mechanism that drives the box-malting machine 10. This allows the apparatus 20
to be inserted
into existing box-making machines as a stand-alone unit operation which does
not need to be tied
into the the same drive that powers the box-making machine. In other
embodiments, the platform
62 can be driven by an apparatus that generates a linear motion. Suitable
apparatuses of this type
include, but are not limited to: a linear motor, a linear actuator, or a
servomotor. In other
embodiments, the cranlt arm 66 can be replaced by a cam so the motor can run
at a more constant
speed that may be more closely tied to the speed of the box-making machine 10.
Rotation of the crank arm 66 in the direction of the arrows by the servomotor
74 causes
the two glue guns 22B and 22C to move back and forth on the rail 63 at an
angle over the carton
path. The glue guns 22B and 22C move between the position shown in Fig. 3 and
the position
shown in dashed lines in Fig. 3. As shown in Fig. 12, the movement of the glue
guns 22B and
22C occurs in such a way that moves the gun nozzles along a path that stays
parallel to the
leading and trailing edges of the moving cartons.
In the embodiment shown, the movement of the glue guns 22B and 22C is kept in
phase
with the movement of the boxes in the box-making machine in the following
manner. The
apparatus 20 is provided with a box or carton position-indicating device. In
this embodiment, the
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
carton position-indicating device is a position feedback device. A suitable
position feedbacle
device is an electromechanical device comprising an encoder (or "resolver")
78. A suitable
encoder 78 for the apparatus shown in the drawings is the XH25D-SS-12,500-TS-
ABZC-4469-
SM18 encoder available from BEI Encoder Division Sensors and Systems Company
of 7230
Hollister Avenue, Goleta, California 93117-2891, USA. As shown in Fig. l, the
encoder 78 is
driven by the belt 12 and pulley 18B that is opposite the pulley 18A which is
being driven by the
drive 14 of the box-malting machine 10. In other embodiments, the encoder 78
can be located in
any other suitable location and driven by any other component, such as other
components of the
box-malting machine 10. The encoder 78 (or other carton position-indicating
device) is in
electrical or electronic communication with the servomotor 74 such as through
a wire, or
otherwise.
In this embodiment, the encoder 78 makes one revolution for each "pitch
length" on the
box-making machine 10. The pitch length can be set at the distance between any
established
point in the box-making process to the next occurrence of that point. In this
embodiment, the
pitch length is set as the distance between the centerline, CL, in Fig. 6, of
each successive spacer
49 between adjacent boxes 24. The encoder 78 can communicate the location of
the boxes 24 to
the servomotor 74. This conununication allows the servomotor 74 to move the
glue guns 22B
and 22C at the proper time to apply glue to the desired portions of the
leading and trailing flaps
42 and 44. In other embodiments, types of devices can be used other than
encoders that allow the
follower (apparatus 20) to be phased in sync with the box-making machine IO
(or master
machine). Such other devices may include, but are not limited to DC motors,
computerized
controllers, and the like.
The two guns 22B and 22C are positioned so that while one moving nozzle
orifice places
a line of glue 50 along the trailing flap 44 of a first carton, the second
movW g gun is placing a
line of glue 52 along the leading flap 42 of the second carton. Two
consecutive revolutions of
the crank arm 66 are required to apply both the leading and the trailing glue
lines 50 and 52 on a
single carton. The apparatus may further include optical devices to ensure
that a carton is present
when the adhesive is to be applied from the glue guns 22.
The possible variations of the embodiment shown in the drawings, include but
are not
limited to the following. In other variations of the embodiment, the two
dynamic glue guns 22B
and 22C can be arranged so that a single pass of the gun platform 62 will
apply glue to the
11
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
leading and trailing flaps of the same carton. In other variations or
embodiments, other types of
linear bearings and rails, or alternatives thereto, can be used.
The apparatus for sealing boxes may provide numerous advantages including, but
not
limited to: (a) improved quality and consistency in flap bonding; (b) less
glue required which
results in significant packaging cost savings; (c) significant maintenance
savings due to the
simpler and more reliable design; and (d) less machine down time, improving
the box-making
line efficiency. However, it should be understood that the claimed invention
may provide these
advantages, but is not required to provide any of these advantages, or any of
the other potential
advantages described throughout this specification.
Other advantages include the ability to use "off the shelf' glue guns which
are much less
expensive than the arrangement of the custom made and carton specific glue
guns and doctor
blades described in the Background of the Invention. The initial set up of the
apparatus is easier
to achieve and maintain for the following reasons: 1) the carton flaps never
make direct contact
with any of the glue gun orifices, therefore, no wear occurs on the external
extremeties of the
glue guns; and 2) a gap exists between the gun nozzle orifices and the carton
flaps. The size of
the gap can vary to some degree without having significant impact on the
quality of the glue bond
achieved.
In addition, the non-contact nature of the glue guns, and a reduction in the
duration
and/or amount of pressure that may be needed to seal the flaps may allow the
amount of
equipment that is generally used to apply pressure perpendicular to the flaps
to seal the flaps to
be reduced or eliminated. When the amount of this equipment is reduced or
eliminated, this
opens up space on the box-making line. The fact that a certain amount of this
equipment was
previously required would place constraints on the size of boxes that could be
sealed on the box-
making machine. Since the amount of this equipment can be reduced and/or
eliminated, there can
be more flexibility in the size of the boxes that can be run on existing box-
making machines. In
the case of new box-making machines, the design of these machines is less
constrained by the
requirements of the glue system.
The disclosure of all patents, patent applications (and any patents which
issue thereon, as
well as any corresponding published foreign patent applications), and
publications mentioned
throughout this description are hereby incorporated by reference herein. It is
expressly not
12,
CA 02476373 2004-08-16
WO 03/082557 PCT/US03/07183
admitted, however, that any of the documents incorporated by reference herein
teach or disclose
the present invention.
While particular embodiments of the subj ect invention have been described, it
will be
obvious to those skilled in the art that various changes and modifications of
the subject invention
can be made without departing from the spirit and scope of the invention. In
addition, while the
present invention has been described in connection with certain embodiments
thereof, it is to be
undersood that this is by way of illustration and not by way of linutation and
the scope of the
invention is defined solely by the appended claims which should be construed
as broadly as the
prior art will permit.
13
