Stock material or miscellaneous articles – Hollow or container type article – Polymer or resin containing
Reexamination Certificate
1999-07-27
2002-03-19
Dye, Rena L. (Department: 1772)
Stock material or miscellaneous articles
Hollow or container type article
Polymer or resin containing
C428S036910, C428S037000, C206S389000, C242S160100, C242S166000, C156S169000, C156S173000
Reexamination Certificate
active
06358586
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a packaging strap coil which is made up of a helically wound thermoplastic resin packaging strap and used in strapping various items, and a method for producing the same. The present invention also relates to a packaging strap coil unit comprising the strap coil, and further relates to a packaging machine equipped with a strap coil reel for loading the strap coil on an automatic packaging machine.
A tape-like thermoplastic resin packaging strap is employed for strapping a corrugated cardboard box or the like. The resin strap is usually manufactured by extrusion-moulding an olefinic thermoplastic resin (i.e. polypropylene, polyethylene terephthalate) into a required flat tape shape, in which case drawing and stretching of the resin is carried out at a rate exceeding the extrusion rate. The stretched resin strap is helically wound up on a tubular paper core to form a strap coil.
The strap coil is loaded on an automatic packaging machine, together with the tubular paper core. A strap therein is successively drawn out to strap a corrugated cardboard box or like item. When the strap coil runs out of the strap, it consists of the tubular paper core. The paper core has been marred by the strap and may not be reused as the core of the packaging strap coil. If the paper core is stained with a synthetic resin-based adhesive, it even fails to make a material for recycled paper. The tubular paper core, which is no longer available as a paper core or a material for recycled paper, is only to be discarded. Disposal of the paper core, however, still requires transportation and waste treating expenses.
In view of the above problems, Japanese Patent Application Laid-open No. 315690/1995 (JP-A-7-315690) discloses a coreless packaging strap coil and a manufacturing method thereof, wherein a packaging strap is helically wound in the absence of a paper or like core. As shown in
FIGS. 57 and 58
, the coreless strap coil
205
has a cylindrical hollow
206
at its axis. The innermost end of the strap
204
is melt-bonded at a melt-bonded area
241
with another strap layer overlaid on the top side thereof.
To produce this strap coil, a strap
204
is wound on a winding roller
201
comprising a pair of separable right/left roller components
203
,
213
. Firstly, the start of the strap
204
is wound in one turn along the middle of the axial length of the winding roller
201
where the right/left roller components
203
,
213
are joined. Then, the strap
204
provides another layer thereon. The laminated strap layers are melted and bonded to each other by applying a heated iron, thereby forming a melt-bonded area
241
. Once the innermost end of the strap
204
is fixed, a predetermined length of the strap
204
is wound on the entire surface of the winding roller
201
to form a strap coil. Finally, the right/left roller components
203
,
213
of the winding roller
201
are disjoined and removed from the strap coil. Thus obtained is a coreless packaging strap coil
205
.
In this packaging strap coil, the fined innermost end of the strap is not drawn out into the hollow at the axis. Therefore, the strap coil remains firm and solid even during transportation.
When this strap coil is loaded on an automatic packaging machine, the strap is drawn out from the outermost end and used for strapping a corrugated cardboard box or like items.
As mentioned above, a heated iron is used to heat a predetermined area on the laminated portion of the strap wound on the winding roller, so that the laminated strap portion is melted and bonded together. However, as the iron fails to give a stable heating temperature, the bonding strength of the laminated strap layers may vary from batch to batch. Provided the innermost end of the strap is bonded too strongly, namely, provided the melt-bonded area possesses too high a peeling strength, the bonded area may not peel readily when used in the packaging machine. In some cases, the strap may be partially torn off at the rigidly bonded area. Actually, when a strap coil is loaded on the automatic packaging machine, the strap is drawn out along with the rotation of the feed rollers. If the laminated layers of the strap are bonded too strongly, the feed rollers may fail to peel off the strap layers, and worse, destroy themselves, depending on the rotation power.
The strap coil of the prior art manifests more defects. As a strap coil is prepared by laminating a strap in a spiral form, it is somewhat extended in the axial direction. Although the innermost end of the strap is bonded with a layer or layers laminated thereon, the rest of the innermost rows of the strap coil which axially neighbour the bonded strap end are left unbonded with respect to the layers laminated thereon.
Such a strap coil may unwind or collapse at the non-bonded area.
For transportation or storage, the prior art strap coils are laid horizontally and stacked on top of each other as shown in
FIG. 55
, with the axis oriented vertically. Usually, a pair of strap coils
101
are vertically stored in a package (shown by imaginary line). Each strap coil
101
has uneven side surfaces by nature, where the edge of the strap
101
a
sticks out in some layers. When a plurality of strap coils
101
are laid axiswise vertically on top of each other, as shown in
FIG. 55
, the edge of the strap
101
a
projecting from the side surfaces of the strap coil
101
can be bent or deformed. The strap coil
101
which includes a strap bent or deformed on the edge is less likely to ensure smooth supply of the strap
101
a
in the automatic packaging machine.
To protect the side surfaces of a strap coil, the strap coil
101
is conventionally transported or stored in the form of a strap coil unit shown in
FIG. 56
, which includes a pair of disc pads
102
applied on each side surface of the strap coil
101
. Each disc pad
102
is made of cardboard and formed with a central hole
102
a
which corresponds to the cylindrical hollow
101
a
at the axis of the strap coil
101
. A pair of pads
102
are integrally joined on the side surfaces of the strap coil
101
by a plurality of straps
103
. Each strap
103
ties the strap coil
101
and the pads
102
together, passing axially through the hollow of the strap coil
101
and the holes of the pads
102
and then axially crossing the outer cylindrical surface of the strap coil
101
.
Since the cardboard pads
102
cover both side surfaces of the strap coil
101
, the edge of the strap
101
a
, even if it may unevenly project or sink, is protected from deformation or damage.
Nonetheless, the preparation of such packaging strap coil units is not a simple task, because the process requires positioning the pads
102
on both side surfaces of the strap coil
101
and thereafter tying them together by a plurality of straps
103
.
As for an automatic packaging machine equipped with a strap coil reel and operated for packaging an item automatically, the strap coil reel usually accommodates a strap coil comprising a strap wound around a tubular paper core. The strap coil reel includes a core element which is inserted into the paper tube and supports the same. As the core element, there may be adopted a cylindrical structure which comprises a cylinder whose diameter is slightly smaller than the inner diameter of the paper tube, a three-parallel-rod structure in which three parallel rods support the inner cylindrical surface of the paper tube at three circumferentially evenly spaced positions, or a flat-plate structure which comprises a pair of parallel plates. When the core element of the strap coil reel holds a tubular paper core, the strap coil reel is rotated by the inertia force generated while the strap is drawn out from the strap coil by the feed rollers.
Unfortunately, in inserting the core element into the hollow of the coreless strap coil, friction with the core element may induce the strap coil to unwind or disintegrate on the inner cylindrical surface thereof. Besides, this core element is not applicable to a coreless
Fujita Kuniaki
Kawamoto Izuru
Marutani Tetsuya
Oba Kazuyuki
Tajika Satoru
Dye Rena L.
Rader Fishman & Grauer
Sekisui Jushi Kabushiki Kaisha
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