Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1995-06-29
2001-06-19
Johnstone, Adrienne C. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S308200, C156S309600
Reexamination Certificate
active
06248194
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention is generally directed to a novel fabricated tube construction and a process for making the same. More particularly, the invention contemplates a tube construction having a novel shoulder that when joined to a sleeve eliminates the leakage problem which occurs with prior art tube constructions.
Fabricated tubes and processes of forming the same are known in the art. In prior art designs, the manufacture of the tube is essentially as described hereinafter. Initially, a sleeve or cylinder is formed out of a stock material by slightly overlapping the ends of the stock material to form a lap seam. A weld or heat seal is effected along the entire length of the overlapping lap seam. The stock material may be laminated and may have multiple layers and an inner foil lining. Next, the resulting cylinder from the stock are cut to a desired length to form individual sleeves. Thereafter, a neck member including a shoulder, to which the sleeve is to be affixed, is positioned on a mandrel. The sleeve is slid over the mandrel until an end portion of the sleeve is brought up into proximity with a mounting portion of the neck shoulder. Subsequently, with the neck shoulder and sleeve on the mandrel, hot air is applied to the mounting portion of the shoulder and the end portion of the sleeve to soften both components. Next, a die, which includes a radio frequency welder, is brought into engagement about the mounting portion of the shoulder for 360° and through the use of radio frequencies, welds the end portion of the sleeve to the mounting portion of the shoulder thereby producing a slight reforming of the end portion of the sleeve so that it conforms to the radius portion of the shoulder. A cap is then put onto the shoulder and the open end of the sleeve is used to fill the tube. After the sleeve is filled with the desired contents, the open end of the sleeve is sealed to complete the process.
With this prior art design, there is a problem of leakage at the point of the overlapping lap seam of the sleeve at the location of welding to the neck shoulder. Leaks most often occur at the void created at the place where the longitudinal lap seam inner layer spaces the overlapping outer layer away from the shoulder because of the inner layer's thickness. It can be appreciated that at this point, a double layer exists and the area at which the outer portion of the sleeve overlaps the inner portion of the sleeve would not always attain a proper, desired seal. Leakage is particularly prominent with three layer laminates having center layers of aluminum or high temperature film stocks.
In prior art tube constructions, the neck member shoulder surface to which the sleeves are heat sealed are smooth and continuous. The heat sealing technique therefore requires that a great deal of heat from a heat die be conducted through the sleeve into the shoulder to fuse both the shoulder and the sleeve together. Often, process parameters and cosmetic issues dictated less than optimum temperature or duration resulting in failure to close the void created by the seam, and thus, leakage results.
The present invention provides a novel tube construction and a process of making the same which eliminates the leakage problem found in prior art tube constructions. Other features and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the present invention is to provide a novel fabricated tube construction and a process for making the same which eliminates leakage problems found in prior art tube constructions due to the tube body overlapping layers.
Another object of the present invention is to provide a fabricated tube construction having a novel neck member shoulder structure that when joined to a seamed sleeve eliminates the leakage problem which occurs with prior art tube constructions.
Yet another object of the present invention is to provide a novel fabricated tube construction which can be easily and cost effectively manufactured.
Briefly, and in accordance with the foregoing, the present invention discloses a novel fabricated tube construction which includes a sleeve formed from flat stock material, which may be laminated, and a novel, plastic neck member and shoulder construction. The sleeve has overlapping edges which are joined together to form a lapped seam. The neck shoulder includes a mounting portion upon which at least one raised, plastic rib is provided. Preferably, a plurality of weld ribs are provided on the mounting portion of the shoulder. Each weld rib extends around the entire periphery of the mounting portion, but may extend only around a portion of the mounting portion. An end portion of the sleeve initially overlays the shoulder such that the lap seam overlays the raised weld rib on the mounting portion. As discussed above, a small, but significant, void results between the lap seam on the sleeve and the mounting portion of the shoulder due to the thickness of the inner layer of the stock material. When the sleeve and the shoulder are joined together, the raised, plastic weld rib melts and flows into the void to fill and seal the void. In addition, a portion of the shoulder melts to form a seal between the shoulder and the sleeve. This results in a leak-proof seal or joint between the sleeve and the shoulder of the neck member.
A process for forming the fabricated tube construction is also disclosed herein. First, flat stock material, which may be laminated, is provided for the sleeve and a neck member with a shoulder having a mounting portion upon which at least one raised, plastic weld rib is provided. The ends of the stock material are overlapped to form a tube, and are welded, heat sealed or otherwise suitably joined together to form a tubular component with a lap seam. The lapped stock material is then cut to length to provide a tubular body or sleeve. Next, an end portion of the tubular body or sleeve is brought into contact with the mounting portion of the shoulder. This step may be effected by placing the neck member on a mandrel or the like and sliding the sleeve over the mandrel until an end portion of the sleeve overlaps the mounting portion of the shoulder. As discussed above, the lap seam forms a small void between the sleeve and the shoulder due to the thickness of the inner layer of the stock material. Thereafter; the shoulder and the sleeve are joined together by a thermal and/or high frequency welding procedure. During this step, the plastic weld rib on the mounting portion melts and flows into the void between the sleeve and the shoulder to seal the void and provide a complete leak-proof joint. A portion of the shoulder will also melt to seal the sleeve and the shoulder together. This step may be effected by directing hot air onto the mounting portion of the shoulder and the end portion of the sleeve to soften the end portion and the mounting portion, and, thereafter, bringing a die into engagement about the mounting portion of the shoulder which welds the end portion of the sleeve and the shoulder together to produce a slight reformation of the end portion of the sleeve so that the sleeve conforms to the mounting portion of the shoulder. The welding operation may be attained by use of frequency welding , ultrasonic welding, heat sealing or some other similar form of thermal welding.
REFERENCES:
patent: 3948704 (1976-04-01), Evans
patent: 4222974 (1980-09-01), Smith
patent: 4259419 (1981-03-01), Uba
patent: 4606470 (1986-08-01), Barlics
patent: 4769095 (1988-09-01), Sager
patent: 5160061 (1992-11-01), Stolzman
Atrion Medical Products, Inc.
Johnstone Adrienne C.
Trexler, Bushnell Giangiorgi, Blackstone & Marr, Ltd.
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