Patent Grant
7325376
Not applicable.
This invention relates in general to the bundling of products for shipping convenience and more particularly to an apparatus and method of bundling loose or bulk products, for example magazines, using a wrapping process that includes binding material that is removable without damaging the bulk products.
Plastic strapping and shrink wrapping are currently the industry standard for securing loose stacks of paper products. Plastic strapping includes one or more straps around a bundle that are not usually fixed to the bundle.
In a traditional plastic strapping process, pre-stacked products such as magazines form a loose stack or bundle that are conveyed out of a stacking mechanism and through a strapping machine. With the aid of a photo eye or some sensory trigger, the strapping cycle is initiated when a strap is fed or pushed through an existing track that forms a hoop that encircles the bundle at a diameter larger than the bundle. The end of the strap makes contact with a clamping mechanism and the feed process is reversed to take up the slack in the strap, thereby liberating the strap from the track and bringing the strap into contact around the bundle. When the tension on the strap reaches a predetermined value, the strap is heat-sealed to the clamped end and then the strap is cut. It is noted that in this traditional plastic strapping process, there is no direct attachment of the strap to the bundle other than the friction caused by the bundle pushing against the hoop strength of the pre-tensioned strap. Additionally, there is currently no widely used or accepted automatic system for removal of the plastic straps from the bundles. Therefore, the plastic straps must be manually removed and this removal includes cutting and discarding the strap or sliding the strap off the end of the bundle.
While a majority of all bundles today reach their destination after being secured in some fashion by wrapping and or strapping as described above, this type of plastic wrapping has a number of disadvantages. To make a durable bundle that will not become loose during shipment, the strap is often installed around the bundle too tightly, thus causing the bundled products to deform and, in some cases, become damaged such that the bundle cannot be reintroduced into any further automated processes. In fact, the damage can be so great that the bundle must be discarded as a damaged product. When the plastic strap is installed loosely enough to prevent the bundle paper products from being deformed and damaged, the plastic strap is often too loose to allow the bundle to be reliably palletized automatically. Additionally, the loose plastic wrapping also makes for unstable manually palletized loads that must themselves be wrapped and strapped. Strapping equipment also has a higher incidence of downtime and a shorter mechanical life span that other equipment in printing industry environments. This is a function of the speed per minute that the bundles must be wrapped. To further exacerbate these problems, the plastic straps must be removed manually from the bundles for further automated processing.
In an alternate form of strapping, the material to be shipped is wrapped with a material that shrinks when warmed, thereby securing the wrapping to the material and generating a secured shipping bundle. In this “shrink wrapping” process, pre-stacked products such as magazines, are positioned to form a loose stack or bundle that are then conveyed out of the stacking mechanism. The stacks are widely spaced via some conveyance medium, usually over two successively faster belt conveyors. The stacks are conveyed without stopping through a machine that has two rolls of film—one over and one under the product. The two rolls of film are joined and cut by a heated wand that melts the two lengths of film together. As the stack moves past the joined rolls, it takes the film with it, both over and under the bundle. When the stack has passed the heated cut-off wand, the two layers of film are cut and joined in one process. The film enshrouded stack is then conveyed through a heat tunnel where hot air causes the film to shrink, thus creating tension and holding the bundle together. The bundle is conveyed out of the heat tunnel and cooled in ambient air.
Once the bundle wrapped by the shrink wrapping process has reached its shipping destination, the shrink wrap material must be removed. There is currently no widely used or accepted automatic system for removal of heat shrink film from bundles. Manual removal of the shrink wrap from the bundle includes cutting and discarding the wrap.
Shrink wrapping has some advantages. For example, the film's coefficient of friction against itself is quite good for use in making pallet loads that are more stable. The bundle also becomes stronger than a stack by itself, thus helping to prevent product damage and paper folding. And, as in the previously described strapping process, most of all bundles usually reach their destination when secured in some shrink wrapped fashion.
However, there are also a number of disadvantages associated with shrink wrapping. For example, shrink wrapping equipment includes a high temperature tunnel that is easily misadjusted thereby causing improper wrapping. During the shrink wrapping process, a bundle stopped in the heat tunnel used to heat and shrink the wrapping material can also ruin the bundle due to the heat, or can actually cause the bundle to burst into flames. The shrink wrapping process also requires burning products that give off potentially toxic gasses and can potentially burn the products.
The completion of the shrink wrapping process also requires extensive use of factory floor space because the bundles must be conveyed down a longer out-feed conveyor needed to allow the heated shrink wrap to cool down. If there is a conveying problem that causes the shrink wrapped bundles to touch each other before the shrink wrap has cooled, the hot bundles can stick to each other. Finally, the shrink wrap material must also be removed manually from bundles for further automated processing making the removal of the shrink wrap labor intensive.
The above bundle packaging methods also present other problems. Bundles of bulk paper items must be transportable without falling apart. The above bundle packaging methods may result in bundles that are too loose or too weak, resulting in unstable loads and loosely strapped bundles that fall apart. While the preferred bundle packaging process must not change its contents, the above examples may result in products damages by crimped bindings, burns, tears, rolled or bent edges, and football-shaped bundles. The above bundle packaging processes are also excessively labor intensive during the process of removing the wrapping material.
A preferable bundle packaging method would likely have a number of preferable characteristics. For example, bundles should maintain bundle integrity for automatic handling of the bundle, such as palletizing, depalletizing, conveying, and sorting, etc. The bundle packaging material should also be automatically removable and include automatic waste removal. Machinery for applying and removing packaging should be reliable with respect to speed, maintenance, and life expectancy. Finally, the packaging material costs for any new packaging process must not exceed current packaging costs. The above-described packaging methods do not offer all of these advantages.
In the accompanying drawings which form part of the specification and wherein like numerals and letters refer to like parts wherever they occur:
While the embodiment of the present invention is illustrated in the above-referenced drawings and in the following description, it is understood that the embodiment shown is merely for purpose of illustration and that various changes in construction may be resorted to in the course of manufacture in order that the present invention may be utilized to the best advantage according to circumstances which may arise, without in any way departing from the spirit and intention of the present invention, which is to be limited only in accordance with the claims contained herein.
The Wrapping Process.
Referring to
The bundle of loose pre-stacked magazines 1, or similar paper products, is conveyed from a stacking mechanism (not shown). The bundle 1 is gapped from any adjacent bundles 1 to allow space between it and the next bundle 1. This spacing is usually accomplished inline by using two speed-up belt conveyors (not shown). In this spacing action, a first conveyor having a set speed transports the bundle onto a second conveyor having a different speed that is greater than the speed of the first conveyor. The speed differential between the first conveyor and the second conveyor causes a bundle that has been placed on the second conveyor to travel faster than the bundle behind that still remains on the first conveyor operating at the slower speed. By the time the next bundle reaches the faster second conveyor, a distance has been generated between the first bundle and the second bundle as both bundles continue on the faster second conveyor.
Using label applying equipment (not shown), the top surface 6 (
The double-sided label 3 could be the entire width of the binding material to be used. In the present embodiment, the width of the binding material is about 1.25 inches, and it is preferred that the glue surface should be not less that 2.50 inches in the other dimension, and it is preferable that there be some glueless overhang in that dimension of about 0.12 inch. In the present embodiment, the double-sided label 3 could be made from any material that meets the requirements described herein, but its size should preferably be about 2.5 inch×about 1.25 inch.
One purpose of the double-sided label 3 is to anchor the binding material to the top magazine cover so that the binding material can be held in tension along its entire width. The double-sided label 3 does this by transferring forces in the binding material to the front page of the top magazine and into that magazine's binding, thus making the top magazine part of the packaging. This works best in the center at the top and bottom of the cover as you hold the magazine as if it was being opened by a reader, and about 1 inch in from the edge.
In the present embodiment, the double-sided label 3 also offers a number of favorable characteristics. For example, the use of two kinds of glue on this label sized object—permanent on one side and removable on the side facing the stack—allows the stronger glue to be used for permanently adhering the binding material to the label. It is also noted that in the present embodiment, it is preferred that the stronger glue be a strong pressure sensitive glue that has excellent lateral load or shear strength characteristics and covers the whole double-sided label 3. For example, when the preferred glue is stuck to the binding material, the binding material will not slip under the loads that are put on the binding material.
The binding material 10 will be pressed onto this label once by the binding material head, while the weaker side of the double-sided label 3 will adhere to the printed cover of the top magazine. Due to the removable nature of the side of the binding material 10 attached to the magazines in the bundle 1, the double-sided label 3 will not leave a tear or mar the surface when the double-sided label 3 is removed. This weaker glue will be similar to a “post it note/removable tape.” The weaker glue should have as much shear strength as possible to keep it from slipping along the paper under tension while simultaneously having a tear strength just below that of the material it is making contact with which, for this embodiment, is a magazine cover. It is also noted that the weaker glue that is on this double-sided label 3 may not cover its entire area.
As the components 2 in the bundle 1 move downward, the two binding material heads 4 contacts the bottom surface 7 of the bundle 1 as shown in
It is appreciated that the application of the binding material 10 occurs while the material 2 in the bundle 1 is in compression from the compressing device 5. When the binding material 10 has been attached to the double-sided label 3, the compression device 5 is removed from the bundle 1 as shown in
In this embodiment of the present invention, the length of a piece of binding material 10 is about twice the height of the bundle 1 plus two extra lengths of about 2 inches on the top surface 6 and about 2.00 inches of the bottom surface 7 of the stack. It will be appreciated by those skilled in the art, that the length of the binding material can be adjusted as need for each unique application while still remaining within the intended scope of the present invention. In a preferred embodiment, the total required length of the binding material 10 for a single bundle 1 in most applications can be calculated via the following:
(2)sides×[height(2)+2.00 inches on top+2.00 inches on bottom]=Length of Overall Binding Material/Bundle.
It has been found that the bundled material has greater stability when the ratio between the dimension of the material being bundled and the width of the binding material is small. For example, a wider binding material results in a more stable bundle. Using the narrowest dimension of the stack of magazines used in the present embodiment, that is, 8.5 inches, the binding material can cover 30% of the width with about a 2.5 inches wide band, whereas, a 3.3 inches wide binding material would be needed to do the same job on the other dimension of 11 inch. For this reason, and in light of the need to stay away from the binding edge of the magazines, the magazines in the present embodiment are wrapped by locating the strapping material along the long 11 inch dimension of the magazine. Additionally, locating the strapping material near the center of the bundle generally works better because this central location minimizes the unbound distance.
The tension in the present embodiment of the invention is introduced evenly through compression of the bundle 1. This is beneficial in that resistance to slippage between the individual items in the bundle 1 increases dramatically when the excess air is gone from the bundle 1. It is also appreciated that it is harder to damage materials through evenly distributed compression rather than point loaded compression in a strapping machine. This means compression can be reached quickly during the packaging process, without damaging the stack material 2 in the bundle 1. The binding material 10 is then wrapping around the stack under enough tension to remove any slack from the binding material. The holding forces that keep the bundled stack together generally come from the expansion of the stack of material 2 when the compression device 5 is removed.
With the combination of the binding material 10 in tension that is wrapped around all four sides and anchored to the top and bottom of the magazine, a stable structure is created that resists torsion in the stack, fanning of the stack rotationally and horizontally, individual magazine slippage pop outs, and bowing of the stack into a shape similar to a football.
The above described embodiment of the present invention offers a number of desirable characteristics including using a strap made of any material that does not stretch under the loads that it will experience and is thin enough to transfer tension around the four trimmed edge corners of the magazine stack it is wrapping. Additionally, the binding material does not have any glue or tack to it.
After the binding material 10 has been applied to the bundle 1, the bundle 1 then leaves the machine and proceeds to a standard palletizer to further prepare for shipment.
The Unwrapping Process.
While the above process may be used where any bundle of loose bulk components must be packaged, other embodiments of the present invention also include additional processing steps for unwrapping the bundle 1. In yet other embodiments of the present invention, only the unwrapping process described herein are included. In fact, it is understood by those skilled in the art that the embodiments of the present invention may include (1) only the process of wrapping a bundle of bulk products as described herein, (2) only the process of unwrapping a bundle of bulk products as described herein, or (3) a combination of wrapping and unwrapping a bundle of packaged bulk products as described herein.
Referring to
While the above description describes various embodiments of the present invention, it will be clear that the present invention may be otherwise easily adapted to fit any configuration where a process for wrapping and/or unwrapping a bundle is required. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. For example, while certain types of manufactures are described herein for the embodiments shown, various other type of manufacturing methods may be used and remain within the scope of the present invention as long as the manufacturing method selected results in the construction of a device that performs the same or similar function as the manufacturing method that is being replaced.
This patent application is related to U.S. Provisional Application Ser. No. 60/614,116 filed on Sep. 29, 2004 from which priority is claimed.
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| 60614116 | Sep 2004 | US |
