Plastic and nonmetallic article shaping or treating: processes – Direct application of fluid pressure differential to... – Producing multilayer work or article
Reexamination Certificate
1998-05-15
2001-09-25
Silbaugh, Jan H. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Direct application of fluid pressure differential to...
Producing multilayer work or article
C264S512000, C264S513000, C264S515000
Reexamination Certificate
active
06294127
ABSTRACT:
TECHNICAL FIELD
The subject invention generally relates to marine fuel tank assemblies and, more specifically to a blow-molded fuel tank assembly having reinforced corners and a method of making same. The method includes the step of molding reinforcements over a portion of a plastic fuel tank body.
Traditionally, plastic containers, such as fuel tanks, have been molded by a variety of techniques such as roto-molding and blow-molding. Historically, blow-molded fuel tanks have been disfavored since their corners are inherently thin. The thin corners leads to inherent weaknesses in the fuel tanks. Because fuel tanks must meet stringent governmental standards for both permeation and fire resistance, the prior art blow-molded tanks have been disfavored due to their proclivity towards permeation of fuel and decreased resistance to fire.
The prior art has not successfully addressed the problems set forth above for blow-molded fuel tanks. Thus, there has been a need for an improved blow-molded plastic container assembly which provides increased strength, low permeability, and increased fire resistance. There has also been a need for an improved blow-molding method of manufacturing these container assemblies.
SUMMARY OF THE INVENTION
The improved storage tank assembly of the present invention provides a blow-molded fluid sealed tank assembly without weakened corners which are typical in blow-molded plastic fuel tanks. The container assembly includes a plastic container body and at least one corner reinforcement. The reinforcement is molded over an outer surface of at least one corner of the container body. The reinforcement includes a peripheral edge which is partially embedded in the outer surface of the container body. The peripheral edge is also partially deformed and becomes partially cohesive with the outer surface of the container body providing locking engagement between the reinforcement and the container body.
In a method according to the present invention, a reinforcement is molded over the corner of a plastic container body leaving a portion of the reinforcement partially embedded in the molded container body. A mold is provided having an inner surface and an orifice, wherein the inner surface of the mold defines an outer surface of the container body. A reinforcement is disposed in the mold orifice with the portion of the reinforcement to be embedded into the container body positioned in the mold. The reinforcement also includes at least one peripheral edge which is partially embedded in the container body. A fluid thermoplastic material is introduced into the mold and forced against the inner surface of the mold and the peripheral edge of the reinforcement. The fluid thermoplastic material softens or partially melts the peripheral edge of the reinforcement. The peripheral edge is partially deformed forming a locking engagement between the container body and the reinforcement. The thermoplastic material comprising the container body and the thermoplastic material comprising the reinforcement can also cohesively bond together providing a secure seal between the container body and the reinforcement. Thus, sufficient thickness can be obtained at the corners without using greater amounts of plastic in the blow-mold process.
In the preferred embodiment, a blow-molded process is used to mold the container assembly. In this process, a fluid parison of thermoplastic material is introduced into the mold and a pressurized gas charge is introduced into the parison expanding the parison and confirming the parison to the inner surface of the mold. The thermoplastic reinforcement is preferably made by injection molding utilizing the same thermoplastic material as is used to form the container body.
The ability to produce parts with good material thickness in corners without making the balance of the part much too thick just to improve corners.
REFERENCES:
patent: 3479421 (1969-11-01), Armbruster et al.
patent: 4207284 (1980-06-01), Speas
patent: 4215089 (1980-07-01), Uhlig et al.
patent: 4307059 (1981-12-01), Cambio et al.
patent: 4952133 (1990-08-01), Hasegawa et al.
patent: 5100204 (1992-03-01), Makihara et al.
patent: 61-123514 (1986-06-01), None
patent: 62-101420 (1987-05-01), None
patent: 1-202420 (1989-08-01), None
Howard & Howard
McDowell Suzanne E
Silbaugh Jan H.
The Moore Company
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