Note: Descriptions are shown in the official language in which they were submitted.
CA 02488340 2004-11-24
SPECIFICATION
APPARATUS AND METHOD FOR PACKAGING SHEET MATERIAL
BACKGROUND OF THE INVENTION
1. Priority
[0001] Priority is claimed to U.S. Provisional Patent Application No.
60/524,773,
filed November 21, 2003, and to U.S. Patent Application No. 10/772,967, filed
February
5, 2004, which claims priority to U.S. Provisional Patent Application No.
60/446,293,
filed February 10, 2003. The disclosure of each of the aforementioned
documents is
incorporated herein by reference.
2. Field of the Invention
[0002] The field of the present invention is sheet material packaging
equipment
and methods.
3. Background
[0003] Dispensers for sheet material are well known to the art and come in
different forms for dispensing a wide variety of sheet materials. In some
cases, the
packaging in which the sheet material is initially placed by the manufacturer
also serves
as the dispenser. In other instances, the sheet material is packaged to
facilitate
placement of the package in the dispenser and to facilitate dispensation
therefrom.
[0004] One common aspect of many of these dispensing methods is that the
sheet material is placed into a U-shaped form before being inserted into the
packaging.
Different methods of forming the sheet material into the U-shaped form are
disclosed in
U.S. Patent Nos. 6,732,492 to Osborne et al. and 6,202,392 to Greenwell et al.
Other
methods, such as the one disclosed in U.S. Patent No. 3,919,827 to Larson et
al., which
discloses an apparatus for folding a stack of bags into a "W" shape prior to
packaging,
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are adaptable to place sheet material into a U-shaped form. The solutions
provided in
the aforementioned patents, however, may not be well suited for all types of
stacked
materials or for all packaging needs.
SUMMARY OF THE INVENTION
[0005] The present invention is directed towards an apparatus and method for
packaging sheet material. Referring to the apparatus, a housing defines a
cylindrical
cavity which is open at both ends. A wall of the housing includes a
longitudinal opening
which intersects the cylindrical cavity. A first forming guide is affixed to
the housing
adjacent to the longitudinal opening and extends into the cylindrical cavity.
A banding
unit is disposed adjacent the downstream end of the cylindrical cavity. The
first forming
guide may extend longitudinally beyond the upstream end of the cylindrical
cavity and
may include parallel walls, each wall being disposed on an opposite side of
the
longitudinal opening. Optional features include a second forming guide which
has a
radially defined end affixed to the housing at the upstream end of the
cylindrical cavity,
a shrink-wrap unit disposed downstream of the banding unit, and a perforation
unit
disposed downstream of the shrink-wrap unit.
[0006] Turning to the method, a U-shaped form is imparted upon a stack of
sheet
material by insertion of the stack into a cylindrical cavity which has a
diameter that is
less than the width of the stack. The U-shaped stack is moved toward and out
of the
downstream end of the cylindrical cavity. The U-shaped stack is then banded as
it
emerges from the cylindrical cavity. When in the cylindrical cavity, a support
may be
inserted into the U-shaped stack, with the support and the U-shaped stack
being moved
together toward and out of the cylindrical cavity. After banding, heat-
shrinkable wrap
may be placed on the banded stack, which may also be perforated following
application
of heat.
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[0007] Accordingly, the present invention provides an improved apparatus and
method for packaging sheet material. Other advantages of the invention will
appear
hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] In the drawings, wherein like reference numerals refer to similar
components:
Fig. 1 is a perspective view of a package of sheet material;
Fig. 2 is a perspective view of a package of sheet material within a
dispenser;
Fig. 3 is a schematic view of an apparatus for use in packaging sheet
material;
Fig. 4 is a perspective view of a forming unit for use in packaging sheet
material;
Fig. 5 is a cross-sectional along the line 5-5 of Fig. 4;
Fig. 6 is a cross-sectional along the fine 6-6 of Fig. 4;
Fig. 7 is a perspective view of the upstream end of the forming unit of Fig.
4;
Fig. 8 is a cross-sectional view of the forming unit of Fig. 4 with a stack of
sheet
material passing therethrough; and
Fig. 9 is a is a perspective view of the downstream end of the forming unit of
Fig.
4 with a stack of sheet material emerging therefrom.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(0009] Turning in detail to the drawings, Fig. 1 illustrates a cartridge 11 of
sheet
material which is a product which may be generated using the following
apparatus and
method. The cartridge includes a U-shaped stack of sheet material 13, a
supporting
insert 15, a heat-shrunken wrap 17, and a band 19. The heat-shrunken wrap 17
and the
band 19 both include perforations 21, 23, respectively, to enable easy access
to the
sheet material 13 when the cartridge 11 is placed in the dispenser 25 shown in
Fig 2.
The bottom of supporting insert 15 extends below the ends of the U-shaped
stack of
sheet material 13 by a small distance 27 to provide stability to the cartridge
11 within the
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dispenser 25. The longitudinal ends of the supporting insert 15 also extend
beyond the
longitudinal ends of the U-shaped stack of sheet material 13 by a small
distance 29 to
provide further stability to the cartridge 12 within the dispenser 25. The
overall size of
the support may vary as desired or as needed to suit a particular dispenser.
[0010] Fig. 3 schematically illustrates a packaging apparatus 31 in which
product
flows in the direction indicated, with the forming unit being at the upstream
end of the
apparatus. A flat stack of sheet material (not shown), preferably interfolded,
initially
passes into the forming unit 33. The forming unit 33 imparts a U-shaped form
upon the
stack of sheet material and allows the support to be inserted into the U-
shaped stack.
The banding unit 35 is disposed downstream of the forming unit 33 and places a
band
around the U-shaped stack of sheet material, preferably as the U-shaped stack
emerges from the forming unit 33. The band is preferably perforated prior to
being
placed around the stack and is preferably constructed from a thin sheet of
paperboard
material, although other suitable materials may also be used. A shrink wrap
unit 37 is
disposed downstream of the banding unit 35. This shrink wrap unit 37 places a
heat
shrinkable wrap about the banded stack of sheet material and heats the heat
shrinkable
wrap so that the shrink wrap snuggly fits about the form of the U-shaped stack
of sheet
material. Lastly, the newly packaged sheet material passes to the perforation
unit 39,
where the perforations are made in the shrink-wrap as shown in Fig. 1.
[0011] The banding unit 35, the shrink wrap unit 37, and the perforation unit
39
are each of a type that are commonly used throughout the packaging industry
and are
thus known to those skilled in the packaging arts. As such, the details
relating to these
downstream units are not discussed further herein.
[0012 A forming unit 33 is illustrated in Figs. 4-6. Referring to Fig. 4, the
forming
unit 33 has three primary parts: the housing 41, the first forming guide 43,
and the
second forming guide 45. The housing includes a cylindrical tube 47, the
interior of
which forms the cylindrical cavity 49, and two annular rings 51, 53 affixed to
the
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cylindrical tube 47, one at the upstream end near the second forming guide 45
and the
second at the downstream end. The cylindrical cavity 49 has a diameter less
than the
width of the stack of sheet material that is to be packaged. The annular rings
51, 53
facilitate introduction of the forming unit 33 into a production line with
other equipment,
such as the banding unit, shrink wrap unit, and perforation unit.
Specifically, the annular
rings 51, 53 provide a convenient surface with which to mechanically attach
the forming
unit to other equipment.
[0013] As can be seen in Figs. 5-6, an opening extends longitudinally in the
wall
of the cylindrical tube 47, spanning from the upstream end to the downstream
end. A
set of flanges 57a, 57b are attached to the cylindrical tube 47 at the
downstream end
thereof, one on either side of the longitudinal opening. The flanges 57a, 57b
are
secured together to help maintain the shape of the cylindrical tube 47. A
second set of
flanges is similarly attached to the upstream end of the cylindrical tube 47
(Fig 6 shows
one flange 59a of this second set). Two longitudinal flanges 61, 63 are also
affixed to
the exterior of the cylindrical tube 47, one on either side of the
longitudinal opening.
These longitudinal flanges 61, 63 are angled slightly away from the
longitudinal opening
to help guide the support into and through the longitudinal opening as
discussed below.
[0014] The configuration of the first forming guide 43 is best seen in Figs. 5
and
6. Referring to Fig. 5, which shows the cross-sectional view of the forming
unit 33, the
first forming guide 43 is constructed of parallel walls 65, 67, each affixed
to the
cylindrical tube 47 on opposite sides of the longitudinal opening. The
combination of the
gap in the cylindrical tube 47 and the parallel walls 65, 67 of the first
forming guide 43
allow insertion of the support into the formed stack of sheet material as the
stack
passes through the forming unit 33. As can be seen in Fig. 6, the two parallel
walls of
the first forming guide merge to form an integral extension 69 which protrudes
beyond
the upstream end of the cylindrical tube 47. The lower portion 71 of this
extension 69 is
tapered to facilitate the passage of a stack of sheet material.
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[0015] Figs. 4 and 6 best illustrate the second forming guide 45. The second
forming guide 45 includes a radially defined end 73 which is affixed to the
upstream end
of the housing 41. The inner radius of the radially defined end 73 is
approximately equal
to the inner radius of the cylindrical tube to allow a stack of sheet material
to easily
transition from the second forming guide 45 into the cylindrical tube 47. The
opposite
end 75 of the second forming guide 45 is linearly defined, having an
approximately
rectangular shape with three physical sides. The side walls of the second
forming guide
45 at the rectangular end 75 are set apart at least as wide as the stack of
sheet
material. The rectangular end 75 of the second forming guide 45 enables a flat
stack of
sheet material to be conveyed from standard packaging equipment directly onto
the
second forming guide 45 without significant, if any, modification to the
standard
equipment. Between the two opposing ends of the second forming guide 45, the
walls of
the second forming guide smoothly transform from the rectangular shape at the
rectangular end 75 to the circular shape at radially defined end 73.
[0016] With the forming guides configured thusly, when a flat stack of sheet
material passes into the rectangular end of the second forming guide and is
pushed
towards the radially defined end, the outer edges of the flat stack curl about
either side
of the extension of the first forming guide. The two forming guides thus guide
the stack
of sheet material into the U-shaped form that allows the stack to pass into
the cylindrical
cavity and is desired for the final product.
[0017] Referring to Figs. 7-9, the process of passing a stack of sheet
material
through the forming unit is illustrated. In Fig. 7, a stack of sheet material
81 is shown
entering the second forming guide 45. The stack 81 is moving toward the
radially
defined end 73 of the second forming guide 45. At this point, the flat stack
of sheet
material 81 is beginning to take on the U-shaped form that is desired for the
final
product. In particular, both sides 83, 85 of the stack 81 are being curled
upward by the
second forming guide 45 to form the legs of the U-shaped form, while as the
stack 81
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moves forward, the middle portion 87 of the stack 81 will be held down by the
lower
edge of the first forming guide 43. Fig. 8 shows the stack of sheet materials
81 within
the cylindrical cavity 49. The support 89 for the final packaged product is
being inserted
through the longitudinal opening in the cylindrical tube 47. The parallel
walls 62, 65 of
the first forming guide allow the support to be inserted into the center of
the U-shaped
form of the stack of sheet material 81. Once the support 89 is inserted into
the stack of
sheet material 81, the stack 81 and support 89 are pushed or guided out of the
downstream end of the cylindrical cavity. Fig. 9 shows the stack 81 emerging
from the
forming unit 33 after it has already had a band 91 placed about it by the
banding unit. At
this point, the stack is ready to be passed to the shrink-wrap unit and then
to the
perforation unit, thereby forming the cartridge 11 shown in Fig 1.
[0018. Thus, an apparatus and a method for packaging sheet material are
disclosed. While embodiments of this invention have been shown and described,
it will
be apparent to those skilled in the art that many more modifications are
possible without
departing from the inventive concepts herein. The invention, therefore, is not
to be
restricted except in the spirit of the following claims.
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