Note: Descriptions are shown in the official language in which they were submitted.
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AN INPROVED CO~POSITF, CONTAINFR
CONSTRUCTION FOR PACRAGING M~TERIALS
UNDER PRESSURE, OR VACUUM CONDITIONS
BACKGROUND OF-T~E INVENTIOW
The present invention relates to an improved com- -
posite ~ontainer construction capable of retaining
goods packaged under.either vacuum or pressure condi-
tions. Although the invention may be utilized in em-
5 bodiments wherein the basic component of the container
wall is either a polymeri~ or a fibrous material, the
invention is particularly suited to applications in
whiah the container wall is a composite fiber construc- :
tion. Accordingly, the discussion to follow will be
10 directed primarily to such an embodiment~
A composite fibex container wall principally is
formed from fibrous materials (such as kraft, chip or t
jute paper) and therefore requires that the inner sur
face of the container be completeIy sealed and that .
15 the metal closures on its o~posite ends be tightly
locked in sealing reIationship onto the container. .
Addition~lly, the container ~ust be capable of easy
opening.
Prese~t methods of manufacturing composite fiber
20 container ~odies.involve convolute or spiral winding
techniques so as to ~orm a tube. The materials used
in forming spiral wound and convolute tubing are pli-
able by nature and therefore are susceptible to dis
placement and fracturing under pressure or vacuum con- :
~5 ditions. For this reason, either immediate leakage
occurs due to fracturing of the container body, or
eventual slow leakage results from a process known
in the industry as "creep". In the latter case, the
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metal end closures tend to work their way loose from
the container over a period of timeO
Because of such problems, composite containers
have not been suitable for certain markets where the
product is packaged under pressure or vacuum condi-
tions. Examples of such products are tennis balls,
coffee, nuts, low pressure aerosols, and the like~
SUMMARY OF THE INVENTION
According to the present invention, a pressure or
vacuum-type composite cont~iner is produced by provid-
ing a reinforcing strip to the cut edges at opposite
ends of the container. Such strips preferably are a
metallic material which can be flanged. These strips
are made integxal with the container ~y being applied
as bands to the composite tubing prior to its being
cut into container lengths. The bands are spaced
along the tubing at the points where it is cut so that
each end of a container includes a strip of a rein-
forcement band. After the cutting operation, the re-
inforcing strips are flanged so as to be adapted toreceive metallic end closures.
To seal a container end, the edge of the closure
is rolled into interlocking relationship with the
flanged reinforcing strip. As a result, the edge of
the container is compressed between the rigid xein-
forcing strip and the end closure, causing it to act
as a gasket. At the same time, the metal-to-metal
contact between the reinforcing strip and the closure
effectively eliminates "creep". By this procedure,
sufficient strength is imparted to the container con-
struction to permit the use of standard can openers
to open the container.
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DETAILED DESCR P~ION OF THE INVENTION
The invention now will be described in greater _-
detail with respect to the a~companying drawings
wherein:
FIGURE 1 is an eIevational ~iew of a segment of ..
composite tubing with metal reinforcing bands bonded
at spaced locations to its outer surface; ....
FIGURE 2 is an enlarged sectional view taken ~
along line 2-2 of Figure l; . .
FIGURE 3 is an enlarged sectional ~iew o~ a por- E
10 tion of the tubing shown in Figure 1 cut to container E
length; .-.
FIGURE 4 is an enlarged sectional ~iew of a seg- _
ment of the tubing shown in Figure 3; ~-
FI.GURE 5 is an exploded sectional ~iew of a por-
15 tion of a metal end closure and its relationship to L__
the segment of tubing shown in Figure 4 after the lat- ~.
ter has been flanged to receive the closure; ,-
FIGURE 6 is a sectional view illustrating the in- F
terlocking relationship created between the portion of
20 metal end closure ana the segment of tubing shown in
Figure 5 after they are brought together into operative -::
relationship; and
FIGURE 7 is an eIevational view paxtially in -
section, illustrating a completed container prior to
25 its being filled. ,.:
Referring to the drawings, Figure 1 illustrate~ ...
a length of composite fiber tubing 10 provided with
metallic rein~orcing bands 12 integrally secured to
the tubing at spaced locations along its length. The ~-.
spacing of the bands corresponds to the desired lengths
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of the containers which are formed by cutting the tu~
ing alony the'circumferential centerlines of the bands. '
Details of a co~tainer body can be appreciated
by reference to Figures 2-4. The container includes a
multi-ply composite fiber wall 14 having strips 16 of
the reinforcing bands 12 at its opposite ends. These '-
strips are securely bonded to the outer surface of '-
wall 10 by a suitable adhesive 1~.
The outer surface of the container can be labeled ~"'
10 prior to the affixing of the reinforcing bands 12 or ~-
after installation o the strips, as indicated by the ~
numeral 20 in Figures 3 and 4. ~
To seal the interior wall of the containar, a _'
lining 22 (illustrated in Figures 2-4~ is employed r"'_'
which typically comprises a barrier layer of material
having a low moisture'or vapor transmission xate, such
as metallic foils, wax and synthetic polymers. The
lining 22 is suitably laminated or adhered to the ex
posed surface of the innermost composite fiber ply 14.
After the tubing 10 has been cut into lengths to ~:
form container bodies', the opposite ends of each body E
are flanged, as shown in Figures 5 and 7. The flanged r
pcrtions fan out whe're the'tubing 10 has been cut, much
liXe'the pages of an opened book, with the reinforcing ~-
strip 16 being at the'outer edge of the flange. If
desired, heat may be applied to the cut edges of the '~"
tubing to soften the reinforcing strips 16 and bonding
agent 18 to facilitate the flanging operation.
Once the flanges have been formed, metal end clo- ,
30 sures can be seated on the container bodies and inter- L
locked with the reinforcing strips 16 by a conventional
can seamer. More particularly, a closure 24 is placed
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over the end of a container body (Figure 5) so that ~-
its edge overlaps th~ flange. The closure then is t-
rolled into contact with the flange such that the edge ,-
of ~he closure pierces label 20 and engages the re-
5 inforcing strip 16. Further rolling by the can seam- ~-
er results in additional deformation of the closure -
edge and the flange to produce a locking actio~ with
the closure 24 in metal-to-me~al contact with strip 16 t-
(Figure 6)~ The interlocking of closure 24 and strip ,::
10 16 produced by the seaming process, and the firm ~:
anchoring of strip 16 to container wall 14, results in ~-
the anchorins of closure 24 to the container. ~~
As is apparent in Figure 6, after the seaming
operat~on, the multi-ply wall 14 and liner 22 are r
15 compressed be~ween reinforcing strip 16 and the end
closure 24 so as to form an air-tight sealing gasket.
To further improve the seal, a suitable seal nt ma- :
terial 26 may be applied to the end closure 24 prior -
to placing the closure in engagement with the flange _
20 at the end of the container body (Figure 5).
The container as it appears just prior to filling
is shown in Figure 7. A~ter it is filled, the entire ~~
container is sealed by applying a further end closure
in the same manner as previously described. r,,
The support provided by the reinforcing strip 16
is the factor that enables the interior of the contain- -
er to be maintained pressurized or partially evacuated :
through secure sealing of ths end closures 24 to the '
container. This holas true regardless of whether the
30 composite fiber wall construction is spirally or con- :
volutely wound, provided the following conditions are
met: ~
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(1) that the reinforcing s~rips are of a ma
terial having suitable strength and rigidity charac- -
teristics; . -
(23 that the strips are place.d so that the !-
flanged wall portions of the container are compressed
between the reinforcing strips and the ena closures; ~
and r_
(3) that thP deformation of the reinforcing
strips so as to contact and overlap the edges of the
closure is sufficient to prevent what is known as
"creep".
By reinforcing the container wall with a rein- '
~orcing strip, the seam formed when the end closura
is secured to the container is given additional
15 strengtht thereby helping to support the seam when it --
is opened by a conventional can opener which uses a ~-
serrated wheel that rides along the seam to drive the r'~-
cutting blade. The reinforcing strip also lends addi~ :
tional support to the container wall directly adjacent _
2Q the seam. _
It should be noted that by reinforcing the
flanged edge of the container wall, the flange is
sufficiently supported to resist breakdown when moist-
ened, as often occurs during liquid fill operations, -
While the preferred embodiment of the invention
has been described with respect to a composite fiber :
container, it will be understood that-the invention
also may be incorporated in a container ~onstruction -
in which the composite wall is a material suitably
lined with an impervious metallic or plastic foil.
