Package making – Methods – Plural covers
Reexamination Certificate
1999-06-03
2001-05-15
Vo, Peter (Department: 3721)
Package making
Methods
Plural covers
C053S066000, C053S168000, C053S399000, C053S526000, C053S589000
Reexamination Certificate
active
06230473
ABSTRACT:
FIELD OF THE INVENTION
This invention is in the field of packing technology and relates to a method and an apparatus for packing serially supplied, substantially parallelepipedic stacks each consisting of a plurality of superimposed, flat articles, such as, e.g., newspapers or magazines. It is possible also to pack other, substantially parallelepipedic articles with the method and apparatus according to the invention.
BACKGROUND OF THE INVENTION
For dispatch purposes, newspapers and magazines are usually stacked, the stacks being strapped at least once with a strap or band and they may be enveloped or wrapped with a film or foil prior to strapping. Stacks packed in this way are stable and easy to handle as a result of the strapping and, due to the film wrapping, at least the outermost products are protected against environmental influences such as moisture or dirt and also against mechanical damage. Depending on the stack stability and on the size of the stacked articles, single or multiple strapping is used, the multiple strapping consisting of at least two parallel straps or of at least two straps at right angles to each other.
For wrapping and strapping serially supplied stacks, as well as of other substantially parallelepipedic articles, the most varied methods and apparatus are known and these are, e.g., described in European patent publication numbers EP-0894721, EP-0890509, and EP-0949341. With most of these methods and apparatus, it is possible to produce, with short cycle times, adequately stable stack packs, provided that the heights of all the supplied stacks falls within a predetermined range and in particular provided that none of the stacks has a height smaller than a predetermined minimum height.
The minimum stack height limitation may have various reasons. The stacked products can, e.g., be so bendable or flexible that in a small stack, they are bent by a taut strap so that the strap loosens and the pack becomes unstable. If the strap is welded together on a perpendicular lateral face of the stack, in a small stack, the weld point can be higher than the stack, so that taut strapping cannot be obtained.
For dispatch purposes, predetermined numbers of newspapers and magazines are made ready by stacking and packing and a dispatch unit usually comprises a plurality of standard packs (stacks with a standard height) and, e.g., one top pack (smaller than the standard pack). Such top packs can contain a very small number of magazines or newspapers or even a single magazine or newspaper. Due to the aforementioned limitation to the stack height in the known strapping machines, the top packs may have to be supplied to a separate apparatus, such that not only additional wrapping/strapping apparatus but also additional conveying paths and switch points are required. Because in most cases it is important that standard and top packs are discharged from the packaging process in the same order in which the stacks forming these packs were supplied, the allocation of the stack flow to different packing machines and the bringing together of the packed flow after packing requires complicated automatic control or necessitates manual reorganization.
SUMMARY OF THE INVENTION
An object of the invention is to provide a method of forming serially supplied stacks of flat articles such as newspapers or magazines into stable packs in which the supplied stacks can have any height between a standard height and a very small height. This means that, with the inventive method, it is possible to pack without difficulties also stacks comprising, e.g., a single newspaper or magazine. The method according to the invention is usable without modifying the stack sequence in a stack flow and with cycle times no longer than the cycle times expected in known stack packing methods. A further object of the invention is to provide an apparatus for performing the method.
According to the inventive method, in a first step a foil or film is placed around each of the serially supplied stacks and is closed to form a wrapping or envelope using a per se known method. In a second step, enveloped or wrapped stacks having a greater stack height are pressed and strapped, whereas enveloped or wrapped stacks having a smaller stack height, and therefore not being able to be packed to form a stable pack by strapping, are finished by side welding the film wrapping instead of, or in addition to, strapping.
To permit the lateral or side welding of the film wrapping for stacks with a smaller stack height, the film material used for wrapping is wider than the corresponding dimension of the stack and the film is placed and closed around the stacks such that top, bottom and two vertical sides of the stack are covered by the film and the film projects from the stack on both sides. In the side-welding step applied to small stacks, the film parts projecting beyond the top and bottom of the stack are joined together. It will be understood that, in this context, the foil or film material can be any form of sheet material, commonly plastic or plastic coated, which is capable of being wrapped around articles and welded or otherwise adhered to itself, examples of such material being known from the prior art.
With the inventive method, larger packs (particularly standard packs, but optionally also larger top packs) wrapped with a film and strapped with at least one taut strap, advantageously perpendicular to the film wrapping, as well as small packs (top packs) wrapped with a film covering the top, bottom and two vertical stack sides and being closed over the two other vertical stack sides by at least spot welds, are produced in a stack-height dependent sequence. In both larger and smaller packs, the stacked articles are not only protected, but are also held in the stack, held in one direction by the film and in the other direction either by a strap or by the side-welded film.
The apparatus for performing the method permits in the same stack position (strapping/welding position) and without any specific setting, welding laterally protruding portions of the film wrapper (side-welding) and/or strapping. The apparatus according to the invention comprises means for wrapping serially supplied stacks with a film, means for pressing wrapped stacks and means for strapping wrapped stacks, the pressing means being equipped as welding means for the side-welding operation, at least the strapping means and the welding means being controlled depending on the stack height of each supplied stack.
For controlling the stack height-dependent packing step, the apparatus is equipped with sensor means for detecting the height of a stack to be packed, or with means for supplying suitable data from a central computer to the apparatus.
REFERENCES:
patent: 3643396 (1972-02-01), Togashi et al.
patent: 4691502 (1987-09-01), Convey, Jr.
patent: 4831809 (1989-05-01), Ballestrazzi et al.
patent: 4956961 (1990-09-01), Janhonen
patent: 5299410 (1994-04-01), Freeman
patent: 6082254 (2000-07-01), De Vlaam
patent: 6085487 (2000-07-01), De Vlaam
patent: 31 40 291 (1983-04-01), None
patent: 0 113 874 (1984-07-01), None
patent: 0 940 341 A1 (1999-02-01), None
Desai Hemant M.
Ferag Verpakkingstechniek B.V.
Rankin, Hill Porter & Clark LLP
Vo Peter
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