Coating processes – Interior of hollow article coating – Metal base
Reexamination Certificate
2000-01-11
2002-04-02
Barr, Michael (Department: 1762)
Coating processes
Interior of hollow article coating
Metal base
C427S284000, C427S287000, C123S337000
Reexamination Certificate
active
06365226
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method of forming a sealant ring within to a throttle body assembly and, more particularly, to a method of closing a gap within a throttle body assembly.
BACKGROUND OF THE INVENTION
Throttle body assemblies are necessary components of fuel injection and combustion engine systems. The throttle body assembly controls the amount of air that is introduced into the system.
Throttle body assemblies typically comprise an essentially cylindrical housing defined by an essentially cylindrical wall member. An essentially circular plate member is pivotally disposed on the wall member. The plate member is pivotably moveable between a closed position to a fully opened position to regulate the amount of air that is introduced into the fuel system. The plate member, when in its closed position, does not continuously abut the cylindrical wall member. As such, an essentially annular gap is formed between the plate member and the wall member. Over time, during use of the fuel system, a carbon-based sludge seal will form between the plate member and the wall member to close the annular gap. This seal will be formed by the fuel system component byproducts.
If this seal is allowed to form during the use of the fuel system, the amount of air introduced, and thus, the operating conditions of the fuel system, will have varied overtime. Accordingly, it is desirable, and has been industry practice, to form a seal in the throttle body assembly to cover the annular gap during production of the throttle body assemblies to provide a throttle body assembly which can have continuous and stable use.
Currently, a high pressure (i.e., about 500 psi)spray head application method is used to apply sealant composition to a throttle body assembly to form the throttle body assembly seal. The sealant composition delivered from the spray head contains a substantial amount of methyl ethyl ketone (MEK) solvent which is a highly volatile and flammable chemical. Typical sealant compositions comprise a Molybdenum disulfide/MEK solution, such as Molydag® from Acheson, which is further diluted with an additional 10-20 weight percent of MEK.
The spray method atomizes the sealant composition to spray the sealant composition over the entire inner surface of about half of the throttle body assembly. This generates a high level of fume inside the spray station where the spraying of the sealant composition takes place. This fume is highly explosive and causes operation complexity and difficulty. For example, in a case where pallet carrying one or more throttle bodies is jammed, or lodged, inside the spray station, an operator cannot simply open the station and fix the pallet immediately. Instead, the operator has to take the process off-line and fill the spray station with carbon dioxide gas and then call a security guard to monitor the fume level to make sure it is safe to open the station. A small and common problem like this can delay the whole assembly process from anywhere from one-half to one and one-half hours.
The spray method also generates excess pollution. One reason for this is that the spray method applies sealant to an area much larger than the gap size. This unnecessary sealant overuse causes additional pollution. Another reason for the additional pollution is that, as discussed above, the molybdenum disulfide composition, as received, is then diluted with an additional 10-20 weight percent MEK before being sprayed. This is done to prevent the spray head from becoming caulked from the atomization of the MEK. Not only does this dilution with the additional MEK result in an extra step of operation, i.e., mixing, but it also increases the material cost and pollution.
Accordingly, it would be desirable to provide a method of forming a sealant ring within a throttle body assembly to close the gap within the throttle body assembly which overcomes the above-mentioned pollution and safety problem found in the current spray method, as well as reducing the cost of providing a sealant ring in throttle body assemblies.
DISCLOSURE OF INVENTION
Accordingly, it is an object of the present invention to provide a method of forming a sealant ring within a throttle body assembly that uses a sealant composition that has less MEK than the sealant composition used with the conventional spray head application method.
It is a further object of the present invention to provide a method of forming a sealant ring within a throttle body assembly which requires less sealant composition per seal than does the conventional spray head application method.
It is yet another object of the present invention to provide a method of forming a sealant ring within a throttle body assembly which overcomes the safety concerns associated with the conventional spray head application method.
It is still yet another object of the present invention to provide a method of forming a sealant ring within a throttle body assembly which can be brought off and on line in a relatively short time compared to the conventional spray head application method.
It is even still yet another object of the present invention to provide a more economical method of forming a sealant ring within a throttle body assembly.
The above and other objects of the present invention are met by providing a method of forming a sealant ring within a throttle body assembly comprising an essentially cylindrical housing defined by an essentially cylindrical wall and an essentially circular plate pivotally disposed on the wall wherein an essentially annular gap is formed between the plate and the wall. The method comprises depositing an essentially continuous ring of sealant composition around the throttle body assembly. The essentially continuous ring covers the essentially annular gap. The sealant composition is dispensed from a needle applicator which is disposed above the annular gap and which travels from a first location in an essentially circular motion around the throttle body until the needle applicator returns to the first location. The sealant composition, upon drying, forms an essentially continuous seal covering the gap of the throttle body.
The above objects of the present invention are also met by providing a method of forming a sealant ring within a throttle body assembly comprising an essentially cylindrical housing defined by a cylindrical wall, and an essentially circular plate pivotally disposed on the wall, wherein an annular gap is formed between the plate and the wall. The method comprises depositing an essentially continuous ring of sealant on the wall and plate to essentially cover the annular gap. The ring is the cured product of an essentially continuous rising of sealant composition. The essentially continuous ring of sealant composition is formed by depositing sealant composition from a needle applicator which travels in a circular motion from a first location around the throttle body assembly until contacting the first location to form a continuous seal over the annular gap.
REFERENCES:
patent: 2578918 (1951-12-01), Boddy et al.
patent: 4695482 (1987-09-01), Weiswurm
patent: 4831977 (1989-05-01), Presswood
patent: 5100699 (1992-03-01), Roeser
patent: 5480487 (1996-01-01), Figini et al.
patent: 5640942 (1997-06-01), Hollister
patent: 5763004 (1998-06-01), Hammen
patent: 40 27 371 (1992-03-01), None
patent: 2131918 (1984-06-01), None
patent: 2 131 918 (1984-06-01), None
Barr Michael
Shelton Larry I.
Visteon Global Technologies Inc.
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