Note: Descriptions are shown in the official language in which they were submitted.
CA 02214865 2005-07-26
CRIMPER ASSEMBLY FOR SEALING OVERLAPPING PORTIONS
OF A SHEET OF PACKAGING MATERIAL
BACKGROUND OF THE INVENTION
s This invention relates in general to form, fill, and seal packaging
machinery of the type in which a continuous sheet of a packaging
material is sequentially folded about a series of articles to be
packaged, hot or cold sealed about the articles, and cut into
individually sealed packages. More specifically, this invention pertains
to to an improved crimper assembly for forming end seals in overlapping
portions of the sheet of packaging material after being folded about an
article.
The formation of a plurality of individually sealed packages of
articles using a single continuous sheet of a packaging material is well
is known in the art. Briefly, the sheet of packaging material is initially
passed through a folding mechanism, which continuously folds the film
over on itself to form an enclosure for a series of spaces apart articles.
The overlapping portions of the film are then sealed along a
continuous longitudinal seal. Next, the folded sheet of packaging
Zo material is fed to a sealing and cutting assembly, which seals the
leading and trailing edges of the package to be formed about the
enclosed article and cuts the tube into a plurality of individually sealed
packages. In some instances, it may be desirable to apply heat during
the process of sealing the overlapping portions of packaging material.
Zs Packages produced by this form, fill, and seal process are
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commonly used for snack bars, candy, cereals, and the like, as well as for
other
non-food articles.
The sealing of the overlapping end portions of the sheet of packaging
material is frequently accomplished by a mechanical crimper assembly. A
s conventional mechanical crimper assembly includes a pair of opposed crimpers
which are disposed on opposite sides of the overlapping portions of the sheet
of
packaging material. The crimpers are provided with respective undulating or
serrated crimping surfaces defined by adjacent peaks and valleys. When the
opposed crimpers are moved into engagement with the overlapping portions of
the sheet of packaging material, the peaks of the first crimping surface are
aligned with the valleys of the second crimping surface, and vice versa. Such
engagement compresses the overlapping portions of the sheet of packaging
material to form an intermeshing seal pattern. In some instances, the sheet of
packaging material is provided with a cohesive coating for accomplishing the
~s seal when compressed. In other instances, an intermediate seal layer of a
coating
or other bonding material is provided.
During the crimping and sealing process, it is important that the crimpers
exert a sufficient amount of force to compress the overlapping portions of the
sheet of packaging material. If an insufficient amount of force is exerted by
the
2o crimpers, then the overlapping portions of the sheet of packaging material
will
not be compressed sufficiently to form a complete seal. At the same time,
however, it is equally important that the amount of force exerted by the
crimpers
not exceed the strength of the sheet of packaging material. If an excessive
amount of force is exerted by the crimpers, the sheet of packaging material
will
2s tear or break. Thus, it is desirable that the amount of force which can be
exerted
by the crimpers against the overlapping portions of the sheet of packaging
material remain within a predetermined range to insure a complete and secure
seal.
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In a conventional crimper assembly, the crimpers and the crimping
surfaces have been formed from a strong, rigid material, such as high strength
steel. Although such crimpers have functioned satisfactorily in the past,
several
drawbacks have been noted. First, in order to insure that the amount of force
s exerted by the crimpers against the overlapping portions of the sheet of
packaging material remains within the predetermined desired range, the initial
set-up of the crimpers on the crimping assembly must be performed very
carefully. This time consuming operation must be repeated whenever it is
desired to change from one film thickness to another and, therefore, is
to inefficient. Second, wrinkles which are occasionally present in the sheet
of
packaging material can cause additional overlapping portions to be compressed
between the opposed crimpers. Because of the rigid nature of the crimpers, the
presence of the wrinkles results in an excessive amount of force being applied
to
the overlapping portions of the sheet of packaging material. Third, in some
~s packages, the number of overlapping layers of the sheet of packaging
material
varies from side to side. This can occur when the package being formed
includes
a longitudinally extending fin seal which is folded to one side. Each of the
two
end seals of the package would thus include a smaller thickness region
(composed of only two overlapping portions of the sheet of packaging material)
2o and a larger thickness region (composed of four overlapping portions of the
sheet
of packaging material). Similar varying thickness regions are found in
packages
containing conventional gusset folds and fin seals. It has been found to be
quite
difficult to set-up the two crimpers so as to exert a proper amount of force
against these different thickness regions of the end seals. Although it is
known
2s to form the crimpers with bowed or recessed areas to accommodate the larger
thickness region, such crimpers are more expensive and still suffer from the
other drawbacks mentioned above. Thus, it would be desirable to provide an
improved structure for a crimper assembly which addresses all of these
drawbacks.
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CA 02214865 1997-09-08
SUMMARY OF THE INVENTION
This invention relates to an improved structure for a crimper assembly for
use in a form, fill, and seal apparatus for sealing overlapping portions of a
sheet
s of packaging material after being folded about a plurality of articles. The
crimper assembly includes upper and lower crimper bars which are supported for
rotation about axes which extend generally perpendicular to the movement of
the
sheet of packaging material. A pair of upper crimpers are secured to opposite
sides of the upper crimper bar, while a pair of lower crimpers are secured to
opposite sides of the lower crimper bars. Each of the upper crimpers includes
a
metallic base having an outwardly facing portion with an undulating cross
sectional shape. A slot is formed in the outwardly facing portion of the upper
crimper, and a cutting blade is retained therein. In a first embodiment, an
insert
is secured to the base of each of the upper crimpers. The insert includes a
rigid
~s shank having a lip portion extending therefrom. Portions of the outer
surface of
the shank are covered by a layer of a relatively resilient material. The layer
is
formed from a material which is suitable for compressing overlapping portions
of
the folded sheet of packaging material to form an intermeshing seal pattern.
The
outwardly facing portion of the layer of resilient material includes a
20 longitudinally extending, outwardly facing resilient crimping surface with
an
undulating cross sectional shape. The lower crimpers are formed in a similar
manner, except that an anvil is retained within the slot. During operation,
the
crimpers are rotated such that the folded sheet of packaging material is
compressed between the downwardly facing undulating surface of the upper
2s resilient layer and the upwardly facing undulating surface of the lower
base. As
a result, the overlapping layers which make up the folded sheet of packaging
material are sealed together to form a trailing edge seal for a packaged
article.
The cutting blade and anvil cooperate to cut the sealed packaging material
into
individual units.
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Various objects and advantages of this invention will become apparent to
those skilled in the art from the following detailed description of the
preferred
embodiments, when read in light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic perspective view of a form, fill, and seal apparatus
for packaging articles including a rotary crimper assembly in accordance with
this invention.
Fig. 2 is an enlarged sectional elevational view of a portion of the form,
fill, and seal apparatus taken along line 2-2 of Fig. 1, showing the sheet of
film
partially wrapped about an article.
Fig. 3 is an enlarged sectional elevational view of a portion of the form,
fill, and seal apparatus taken along line 3-3 of Fig. l, showing the sheet of
film
fully wrapped about the article, but prior to being sealed and cut into
is individually sealed packages.
Fig. 4 is an enlarged sectional elevational view of the crimper assembly
illustrated in Fig. 1 including a first embodiment of a pair of cooperating
upper
and lower crimpers.
Figs. 5, 6, and 7 are further enlarged sectional elevational view of a
2o portion of the crimper assembly illustrated in Fig. 4 which sequentially
illustrates
the sealing process as the upper and lower crimpers are rotated and engage a
folded sheet of the packaging material.
Fig. 8 is an enlarged sectional elevational view of the crimper assembly
illustrated in Fig. 1 including a second embodiment of a pair of cooperating
2s crimpers in accordance with this invention.
Fig. 9 is an enlarged sectional elevational view of the crimper assembly
illustrated in Fig. 1 including a third embodiment of a pair of cooperating
crimpers in accordance with this invention.
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Fig. 10 is an enlarged sectional elevational view of the crimper assembly
illustrated in Fig. 1 including a fourth embodiment of a pair of cooperating
crimpers in accordance with this invention.
Fig. 11 is an enlarged sectional elevational view of the crimper assembly
s illustrated in Fig. 1 including a fifth embodiment of a pair of cooperating
crimpers in accordance with this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, there is schematically illustrated in Fig. 1 a
form, fill, and seal apparatus, indicated generally at 10, in accordance with
this
invention. The apparatus 10 is generally conventional in the art, and only
those
portions which are necessary for a complete understanding of this invention
will
be explained. The apparatus 10 includes means for supporting a roll 11 of a
conventional packaging material, such as polypropylene films, saran films, or
~s laminations of a plurality of films. A sheet 12 of the packaging material
is payed
out from a roll 11 and fed around various rollers 13 to a folding shoe 15. The
folding shoe 15 is conventional in the art and is provided to continuously
fold
the longitudinal edges of the sheet 12 of packaging material about the sides
of a
plurality of articles 16 which are moved longitudinally along a conveyor 17.
The
2o folded sheet 12 of packaging material is then moved along a support surface
18.
As the folded longitudinal edges of the sheet 12 are moved along the
support surface 18, they are engaged by a pair of folding rollers 20 disposed
beneath the support surface 18. As a result, the longitudinal edges of the
sheet
12 of packaging material are further folded downwardly in an overlapping
2s manner, as shown in Fig. 2. Then, a pair of grooved heat seal rollers 21
disposed
beneath the support surface 18 engage the overlapping edges of the sheet 12 of
packaging material so as to create a continuous longitudinal fin seal 12a (see
Fig.
3). The fin seal 12a is next engaged by a pair of pull rollers 22, also
disposed
beneath the support surface 18, which advance the folded sheet 12 of packaging
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CA 02214865 1997-09-08
material (and the articles 16 enclosed therein) through the apparatus 10. A
deflector 18a is provided in the support surface 18 to fold the fm seal 12a
upwardly into flush engagement with the folded sheet of packaging material, as
shown in Fig. 3.
s A rotary crimping assembly, indicated generally at 30, is provided in the
apparatus 10 for laterally crimping and cutting the folded sheet 12 of
packaging
material so as to form a plurality of individually sealed packages, such as
shown
at 16a in Fig. 1. The crimping assembly 30 includes an upper crimper bar 31
which is disposed above the support surface 18 for rotation about an axis
extending generally perpendicular to the longitudinal movement of the sheet 12
of packaging material. A pair of upper crimpers, indicated generally at 32,
are
secured to opposite sides of the upper crimper bar 31 for rotation therewith.
The
structure of one of the upper crimpers 32 will be explained in detail below.
Similarly, the crimping assembly 30 includes a lower crimper bar 33 which is
is disposed below the support surface 18 for rotation about an axis extending
generally perpendicular to the longitudinal movement of the sheet 12 of
packaging material. A pair of lower crimpers, indicated generally at 34, are
secured to opposite sides of the lower crimper bar 33 for rotation therewith.
Referring now to Figs. 4 through 7, a first embodiment for the structures
20 of the upper and lower crimpers 32 and 34, respectively, is illustrated in
detail.
As shown therein, the upper crimper 32 includes a metallic base 40 which
extends along a portion of the upper crimper bar 31 and is secured thereto by
threaded fasteners 31a (see Fig. 1) or any other conventional means. A
longitudinally extending opening 41 is formed through the base 40 of the upper
2s crimper 32. The opening 41 is provided to accommodate a conventional
heating
element (not shown) which can be disposed within the base 40 to raise the
temperature thereof for heat sealing applications. The heating element is
omitted
from the opening 41 for cold sealing applications.
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The inwardly facing portion of the base 40 is formed having a flat surface
42 which abuts a correspondingly shaped mounting surface (not shown)
provided on the upper crimper bar 31 when secured thereto. The outwardly
facing portion of the upper crimper 32 includes a longitudinally extending,
s outwardly facing rigid crimping surface 43. As best shown in Figs. 5 through
7,
the rigid crimping surface 43 is formed having an undulating cross sectional
shape. The purpose for this undulating cross sectional shape will be explained
below. The outwardly facing portion of the upper crimper 32 also includes a
longitudinally extending slot 44. A conventional cutting blade 45 is disposed
to within the slot 44 and retained therein by threaded fasteners (not shown)
or any
other known retaining mechanism. The cutting blade 45 is formed having a
sharp serrated edge which extends outwardly away from the upper crimper bar
31. The outwardly facing portion of the upper crimper 32 further includes a
longitudinally extending recess 46.
is An insert, indicated generally at 50, is disposed within the recess 46 and
is secured to the base 40 of the upper crimper 32 by a plurality of threaded
fasteners, one of which is illustrated at 51 in Fig. 4. However, it will be
appreciated that the insert 50 may be secured to the base 40 by any other
retaining means. The insert 50 includes a shank 52 having a lip portion 52a
(see
2o Figs. 5 through 7) extending therefrom. The illustrated shank 52 extends
longitudinally throughout the recess 46 formed in the base 40 of the upper
crimper 32. The illustrated lip portion 52a extends generally perpendicular to
the shank 52 so as to define a generally L-shaped cross sectional shape. The
outer end of the lip portion 52a extends adjacent to the undulating rigid
crimping
2s surface 43 of the base 40. The shank 52 is preferably formed from a
relatively
strong and rigid material, such as steel.
Portions of the outer surface of the shank 52 are covered by a layer of a
relatively resilient material. The layer 53 is formed from a material which is
suitable for compressing overlapping portions of the folded sheet 12 of
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CA 02214865 2005-07-26
packaging material to form an intermeshing seal pattern, as will be described
in detail below. The specific material used to form the layer 53 will vary
from
application to application. For cold sealing applications, the layer 53 may be
formed from a resilient polyurethane material, such as ether or ester. For
s heat sealing applications, the layer 5 may be formed from a synthetic rubber
material, such as EPDM or Viton*. Preferably, the layer 53 has a durometer
hardness in the range of from about sixty to about one hundred ten, and
preferably within the range of from about seventy-five to about ninety-five.
The layer 53 may be molded about the desired portions of the shank 52 or
to applied thereto in any other known manner. Preferably, however, a portion
of
the layer 53 extends around the end of the L-shaped shank 52 as illustrated
so as to prevent the layer 53 from separating from the shank 52 during use.
The outwardly facing portion of the layer 53 of resilient material
includes a longitudinally extending, outwardly facing resilient crimping
is surface 53a. As best shown in Figs. 5 through 7, the resilient crimping
surface 53a may be formed having an undulating cross sectional shape. This
undulating shape is preferable for use with the illustrated rotary crimping
assembly 30. However, the crimping surface 53a may be formed having
other shapes, such as flat, for other applications. The purpose for this
2o undulating cross sectional shape will be explained further below.
The lower crimper 34 is formed in a similar manner as the upper
crimper 32, and like reference numbers are used in the drawings to indicate
identical structures. Thus, the lower crimper 34 includes a metallic base 40
having longitudinally extending opening 41, a flat surface 42, a
2s longitudinally extending, outwardly facing rigid crimping surface 43, and a
longitudinally extending slot 44. Rather than providing the cutting blade 45,
a conventional anvil 47 is disposed within the slot 44 of the lower crimper
and retained therein by threaded fasteners (not shown) or any other known
retaining mechanism. The anvil 47 is formed having a slightly curved outer
3o surface which extends
Trade-mark
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outwardly away from the lower crimper bar 33. The outwardly facing portion of
the lower crimper 34 further includes a longitudinally extending recess 46. An
insert, indicated generally at 50, is disposed within the recess 46 and is
secured
to the base 40 of the lower crimper 34. The insert 50 includes a shank 52
having
s a lip portion 52a extending therefrom, and portions of the outer surface of
the
shank 52 are covered by a layer 53 of the relatively resilient material having
an
outwardly facing, resilient, and undulating crimping surface 53a.
Referring to Figs. 5 through 7, the operation of the upper and lower
crimpers 32 and 34 is illustrated in detail. As mentioned above, the upper and
to lower crimpers 32 and 34 are respectively secured to the upper and lower
crimper bars 31 and 33 for rotation. As the folded sheet 12 of packaging
material is moved along the support surface 18 in the direction of the central
arrow, the upper and lower crimpers 32 and 34 are rotated as shown in Figs. 5,
6,
and 7 in the directions of the upper and lower arrows, respectively. As a
result,
1s the leading edges of the upper and lower crimpers 32 and 34 initially
engage the
folded sheet 12 of packaging material, as shown in Fig. 5. When this occurs,
the
folded sheet 12 of packaging material is compressed between the downwardly
facing undulating surface 53a of the upper resilient layer 53 and the upwardly
facing undulating surface 43 of the lower base 40. As a result, the
overlapping
20 layers which make up the folded sheet 12 of packaging material are sealed
together to form a trailing edge seal for a packaged article 16.
Further movement of the folded sheet 12 of packaging material and
rotation of the upper and lower crimpers 32 and 34, respectively, is
illustrated in
Fig. 6. As shown therein, the crimpers 32 and 34 have rotated to a position
2s where the cutting blade 45 is aligned with the anvil 47. Consequently, the
folded
sheet 12 of packaging material is cut longitudinally into two pieces. Still
further
movement of the folded sheet 12 of packaging material and rotation of the
upper
and lower crimpers 32 and 34, respectively, is illustrated in Fig. 7. As shown
therein, the trailing edges of the upper and lower crimpers 32 and 34 engage
the
CA 02214865 1997-09-08
folded sheet 12 of packaging material to compress the folded sheet 12 of
packaging material between the downwardly facing undulating surface 43 of the
upper base 40 and the upwardly facing undulating surface 53a of the lower
resilient layer 53. As a result, the overlapping layers which make up the
folded
s sheet 12 of packaging material are sealed together to form a leading edge
seal for
the next packaged article 16 on the conveyor 17.
Preferably, the upper and lower crimpers 32 and 34 are arranged such that
the resilient layers 53 are within the range of from about 85% to about 95% of
their uncompressed thicknesses when as shown in Figs. 5, 6, and 7. The
to resiliency of the resilient layers 53 allows the crimping assembly 30 to
accommodate wrinkles and variations in the thickness of the sheet 12 of
packaging material, while insuring the formation of a secure seal. One of the
other advantages of the invention is that the inserts 50 can be removed for
inspection and replacement without requiring removal of the cutting blade 45
or
~s the anvil 47.
Referring now to Fig. 8, there is illustrated a second embodiment for the
structures of the upper and lower crimpers 32' and 34'. As shown therein, the
upper and lower crimpers 32' and 34' are formed having essentially the same
structure as the upper and lower crimpers 32 and 34 discussed above, and like
2o reference numbers are used to indicate identical structures. However, the
inserts
50 of the above-described upper and lower crimpers 32 and 34 have been
replaced by modified inserts, indicated generally at 60, in the alternative
upper
and lower crimpers 32' and 34'. As discussed above, the inserts 50 were
composed of the shanks 52 having the respective layers 53 of resilient
material
2s molded thereto. The modified inserts 60 are formed solely of the resilient
material, having no rigid shank contained therein. The crimpers 32' and 34'
function in the same manner as described above. The openings 41 for the
heating elements have been omitted from the modified crimpers 32' and 34' to
indicate that such need not be provided in either of the embodiments.
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Referring now to Fig. 9, there is illustrated a third embodiment for the
structures of the upper and lower crimpers 32" and 34". As shown therein, the
upper crimper 32" includes a metallic base 70 which is adapted to extend along
a portion of the upper crimper bar 31 and be secured thereto by threaded
s fasteners (not shown) or any other conventional means. The inwardly facing
portion of the base 70 is formed having a flat surface 71 which abuts a
correspondingly shaped mounting surface (not shown) provided on the upper
crimper bar 31 when secured thereto. The outwardly facing portion of the base
70 includes a longitudinally extending, outwardly facing rigid crimping
surface
~0 72. As discussed above, the rigid crimping surface 72 can be formed having
an
undulating cross sectional shape. The outwardly facing portion of the base 70
also includes a longitudinally extending slot 73 having a conventional cutting
blade 74 disposed therein.
The lower crimper 34" includes a metallic base 75 which is adapted to
is extend along a portion of the lower crimper bar 33 and be secured thereto
by
threaded fasteners (not shown) or any other conventional means. The inwardly
facing portion of the base 75 is formed having a flat surface 76 which abuts a
correspondingly shaped mounting surface (not shown) provided on the lower
crimper bar 33 when secured thereto. The outwardly portions of the base 75 are
2o covered by a layer 77 of a relatively resilient material. The outwardly
facing
portion of the layer 77 of resilient material includes a longitudinally
extending,
outwardly facing resilient crimping surface 78 having an undulating cross
sectional shape. The outwardly facing portion of the base 75 also includes a
longitudinally extending slot 79 having an anvil 80 disposed therein. The
2s crimpers 32" and 34" function in the same manner as described above.
Referring now to Fig. 10, there is illustrated a fourth embodiment for the
structures of the upper and lower crimpers, indicated generally at 32"' and
34"'
As shown therein, the upper and lower crimpers 32"' and 34"' are formed
having essentially the same structure as the upper and lower crimpers 32 and
34
12
CA 02214865 1997-09-08
discussed above. However, the upper and lower crimpers 32"' and 34"' include
upper and lower inserts, indicated generally at 90 and 91, having respective
modified upper and lower shanks 92 and 93. The upper and lower shanks 92 and
93 have respective lip portions 92a and 93a extending therefrom. A
s longitudinally extending notch or ledge 94 is formed in the lower edge of
the
upper shank 92. Similarly, a longitudinally extending notch or ledge 95 is
formed in the upper edge of the lower shank 93. Each of the ledges 94 and 95
is
preferably arcuate in cross section. A first portion of the ledge 94 of the
upper
shank 92 faces toward a leading edge 100 of the upper insert 90, while a
second
io portion of the ledge 94 faces downwardly toward the lower insert 91.
Similarly,
a first portion of the ledge 95 of the lower shank 93 faces toward a trailing
edge
101 of the lower insert 91, while a second portion of the ledge 95 faces
upwardly
toward the upper insert 90. The purpose for the ledges 94 and 95 will be
described below. The upper and lower inserts 90 and 91 further include
~5 respective layers 102 and 103 of relatively resilient material. The layer
102
surrounds the Iip portion 92a, the ledge 94, and the leading and trailing
sides of
the upper shank 92, while the layer 103 surrounds the lip portion 93a, the
ledge
95, and the leading and trailing sides of the lower shank 93.
The ledges 94 and 95 provide additional mechanical support for the layers
20 102 and 103 of the relatively resilient material during the crimping
process.
Specifically, the ledge 95 of the lower shank 93 supports the layer 103 of the
resilient material at the trailing edge of the lower insert 91 during the
final stage
of the crimping process, such as shown at Fig. 7 above. It has been found that
the lower layer 103 of the relatively resilient material may, in some
instances, be
2s pulled away from the lower shank 93 as a result of the forces generated
during
the crimping process. This pulling away can result in undesirable delamination
of the lower layer 103 from the lower shank 93. The mechanical support
provided by the ledge 95 tends to prevent such delamination. The delamination
problem appears to be more troublesome on the trailing edge of the lower
insert
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CA 02214865 1997-09-08
91. Thus, the ledge 94 illustrated on the upper shank 92 may be omitted if
desired. Alternatively, a ledge may be provided on the trailing edge of the
upper
shank 92.
Referring now to Fig. 11, there is illustrated a fifth embodiment for the
s structures of the upper and lower crimpers, indicated generally at 32"" and
34"". As shown therein, the upper and lower crimpers 32"" and 34"" are
formed having essentially the same structure as the upper and lower crimpers
32
and 34 discussed above. However, the upper and lower crimpers 32"" and
34"" include upper and lower inserts, indicated generally at 110 and 111,
io having respective modified upper and lower shanks 112 and 113. The upper
and
lower shanks 112 and 113 have respective lip portions 112a and 113a extending
therefrom. A longitudinally extending notch or ledge 114 is formed in the
lower
edge of the upper shank 112. Similarly, a longitudinally extending notch or
ledge 115 is formed in the upper edge of the lower shank 113. Each of the
~s ledges 114 and 115 is preferably arcuate in cross section. A first portion
of the
ledge 114 of the upper shank 112 faces toward a leading edge 120 of the upper
insert 110, while a second portion of the ledge 114 faces downwardly toward
the
lower insert 111. Similarly, a first portion of the ledge 115 of the lower
shank
113 faces toward a trailing edge 121 of the lower insert 111, while a second
2o portion of the ledge 115 faces upwardly toward the upper insert 110. The
upper
and lower inserts 110 and 111 further include respective layers 122 and 123 of
relatively resilient material. The layer 122 surrounds the lip portion 112a,
the
ledge 114, and the trailing side of the upper shank 112, but does not extend
over
the leading side of the upper shank 112. The layer 123 surrounds the lip
portion
2s 113a, the ledge 115, and the leading side of the lower shank 113, but does
not
extend over the trailing side of the lower shank 113. The purpose for the
ledges
114 and 115 is the same as described above in connection with Fig. 10.
It has been found to be desirable to form the shanks 52, 92 and 93, and
112 and 113 from an aluminum alloy material, such as 6061 T-6 aluminum alloy.
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It has been found that the layers of resilient material appear to bond more
securely to such aluminum alloy material, thereby tending to prevent
delamination as described above.
In accordance with the provisions of the patent statutes, the principle and
s mode of operation of this invention have been described in its preferred
embodiments. However, it should be noted that this invention may be practiced
otherwise than as specifically illustrated and described without departing
from its
scope. For example, the crimpers of this invention have been described and
illustrated in the context of an otherwise conventional rotary crimping
assembly.
It will be appreciated, however, that the crimpers of this invention may be
utilized in other types of conventional crimping assemblies, such as walking
bar
and intermittent crimping assemblies, wherein one or both of the crimpers are
moved in such a manner as to engage and compress the packaging material
therebetween.
