Package making – Methods – Wrapping contents including cover forming
Reexamination Certificate
2000-08-21
2003-01-14
Sipos, John (Department: 3721)
Package making
Methods
Wrapping contents including cover forming
C053S214000, C053S372900
Reexamination Certificate
active
06505459
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for wrapping paper and board rolls into a wrapper having a width smaller than the overall width of the roll.
BACKGROUND OF THE INVENTION
In the paper industry, paper rolls are conventionally packaged into a wrapper wound about the roll and then headers are placed on the ends of the roll. The purpose of the wrapper is to protect the roll from moisture, mechanical blows and to facilitate automated handling without the risk of damaging the roll itself. Frequently, two or more narrow rolls are typically wrapped in the same package, whereby the wrapper must be made sufficiently strong to keep the package intact. The wrapper material is of a thick paper or board, which may be coated with a plastic or, alternatively, comprised of a multilayer structure of different materials. The rims of the wrapper are conventionally allowed to extend over the roll edges and they are then crimped over inner headers placed to the roll ends and glued in place with the help of outer headers. Typically, the wrapper width is selected to be sufficiently wide so as to extend over the entire width of the roll being wrapped and provide an overlap for crimping over the roll edges. Hence, a paper mill must keep a plurality of different wrapper widths available, because the widths of produced rolls are obviously dictated by the roll width orders placed by customer. Obviously, a wrapping machine designed to operate at different wrapper widths is very complicated and expensive, because it must have support means for wrapper rolls of different widths and equipment for dispensing each wrapper type of different width to the roll being wrapped.
The roll to be wrapped may alternatively be wrapped by winding a number of wrapper plies thereon. Glueing is used to assure a positive locking of the wrapper plies on the roll and sufficient strength of the wrapper. The glueing of the wrapper may be implemented by spraying on the wrapper surface a hot-melt glue, which may be applied as a stripe or dots. It is also possible to use a wrapper with a thermoplastic polymer coating that is hot-melted prior to winding the wrapper on the roll surface. Conventionally, the wrapping operation is carried out by first adhering the wrapper to the roll surface and then glueing the last plies of the wrapper to each other. U.S. Pat. No. 5,265,399 describes a method and apparatus for making a roll package by means of a wrapper having its surface coated with a layer of a thermoplastic binder. In this method, the binder coat on the wrapper surface is melted in order to adhere the leading end of the wrapper to the roll and the trailing end to the last plies when the wrapping operation is completed. Further, at least some of the wrapper plies are adhered by heat-melting to each other during the wrapping operation. The wrapper width is equal to the full width of the roll and the hot-melted area is controlled by zones in order to obtain desired glueing patterns and cope with different wrapper widths. Also in this method, a plurality of different wrapper widths are used, whereby the wrapper machine must contain several wrapper rolls. The number of wrapper rolls may be 10 and more, whereby at least a portion of the wrapper rolls will have a long dispensing distance from the wrapper roll to the roll being wrapped. This may cause problems in threading the leading end of the wrapper. A wrapper machine of the above-described type must have separate backstands for rolls of different widths or, alternatively, separate storage sites from which the rolls are fetched to the wrapping machine. As a result, such a wrapping machine requires a very large footprint.
Canadian Patent Application No. 2,184,857 describes a wrapping machine in which a wrapper narrower than the width of the rolls being wrapped is wound about the roll obliquely to the center axis of the roll. The wrapper is adhered by a flowable glue or binder to both the surface of the roll being wrapped and the overlapped portion of the wrapper plies. The wrapper is not wound up to the roll ends, but instead, they are left partially free and, after the obliquely wound portion of the wrapper is completed, the wrapper roll is rotated so that the roll ends can be wrapped with circumferential wrapper portions overlapping the roll ends. These wrapper portions that extend over the roll ends are crimped against the roll ends in a conventional manner. While this method manages using a single-width wrapper roll only, the width of the wrapper must be very narrow due to the oblique wrapping technique in order to achieve reliable wrapping and to avoid leaving an excessively large unwrapped area. at the roll ends. The method provides a two-ply wrap package, but as a consequence of the obliquely wound structure of the wrap, the strength of the package cannot be increased essentially by using a greater number of wrap plies. Due to the narrow width of the wrapper, the wrapper equipment has a limited capacity and operates at a slow pace, because the roll must be rotated over a great number of revolutions, during which the wrapper roll position must be altered and it must be moved between the ends of the roll being wrapped. Such roll rotating and transfer equipment makes the wrapper machine complicated with respect to its wrapping capacity and its complex construction increases the cost of the machine. Moreover, this technique is incapable of wrapping a number of rolls in a single package, because the narrow circumferential wrapper at least in a two-ply wrap fails to support the package reliably at the abutting inner ends of the adjacent rolls.
International patent application No. PCT/FI97/00322 discloses an apparatus for wrapping rolls wider than the wrapper width with a narrow wrapper using a plurality of overlapping wrapper plies wound over the entire length of the roll. In this apparatus, the rolls to be wrapped are brought to the wrapping station and first located therein by aligning their first ends with the edge of the wrapper. Next, a required amount of wrapper is wound about said first end of the roll and then the second end of the roll is aligned with the other edge of the wrapper, after which a second number of wrapper plies is wound about the roll. In this method, the wrapper width must be equal to the width of the narrowest roll to be wrapped, because the wrapper may not extend over the roll ends. This requirement results from the fact that the above-described wrapper apparatus is intended for such a wrapping technique in which no headers are placed to the roll ends, whereby the overlapping rims of the wrapper cannot be crimped against the roll ends. The wrapper is fixed in place by glueing in a conventional manner. While no detailed description is given for the applied glueing technique, conventionally roll packages are secured using, e.g., a hot-melt glue which is dosed in dots or stripes. Such a glueing method does not necessarily give a sufficiently strong and moisture-proof package when the wrap is made from a number of adjacent wrapper plies.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method and apparatus suited for packaging paper and board rolls in a wrapper narrower than the roll width and simultaneously rendering a strong and highly durable package with a good moisture resistance.
The goal of the invention is achieved by wrapping the rolls to be packaged in a wrapping consisting of at least two plies of adjacent turns of a packaging wrapper having its surface coated with a hot-melting and cool-adhering binder material which is melted prior to the wrapping of the wrapper about the roll so that at least the first ply of the wrapper at the portion extending over the roll end is not heated and at least the superimposed portions of wrapper plies at the crimped wrapper edges and the overlapping portions of the adjacent wrapper plies are hot-melt bonded to each other.
Frequently, also the first ply of the wrapper facing the roll surface is hot-melt bonded to attach the wrapper to the roll and
Forsström Risto
Ojala Pertti
Ruohio Raimo
Cohen & Pontani, Lieberman & Pavane
Sipos John
Valmet Corporation
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