Seal for a joint or juncture – Seal between fixed parts or static contact against... – Contact seal between parts of internal combustion engine
Reexamination Certificate
1998-11-02
2001-01-30
Knight, Anthony (Department: 3626)
Seal for a joint or juncture
Seal between fixed parts or static contact against...
Contact seal between parts of internal combustion engine
C277S600000, C277S637000, C277S654000, C029S888300, C024S618000
Reexamination Certificate
active
06179298
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a gasket and more particularly to a multiple layer gasket having a snap-fit attachment element to positively attach multiple gasket layers together.
BACKGROUND OF THE INVENTION
Gaskets are often used to seal mating mechanical components. One common application involves the placement of a gasket between a head and an exhaust manifold of an internal combustion engine. Another application involves gasket placement between the exhaust manifold and an exhaust pipe flange. Gaskets for either application are considered high temperature gaskets and more particularly exhaust manifold gaskets since they provide an exhaust seal that prevents the by-products of combustion exiting the combustion chamber from escaping a vehicle engine.
In a metallic laminate gasket for an exhaust manifold of an internal combustion engine, the gasket is formed from a plurality of metallic gasket layers laminated together. The metallic layers provide structural support between the manifold and engine block, and radial strength to resist gasket blow-out due to combustion chamber generated pressures. Typically, the metallic layers are laminated together by welding. However, welding is undesirable for a number of applications. For example, welding is a time consuming process and involves specialized tooling, thus increasing manufacturing costs. Further, the metallic layers may become warped, thereby compromising sealing effectiveness, due to the high weld temperatures generated. Additionally, weld beads formed by the welding operation may reduce the force available for sealing the gasket layers as weld beads can interfere with mating members before they are fully tightened together.
To avoid the difficulties associated with welding, it has been known to provide a metallic gasket with a plurality of bending strips that cooperate with holes for connecting first and second metal plates together. A hole is formed in the first plate while a bending strip extends from the second plate. The bending strip is passed through the hole of the first plate where it is bent over to engage an outer surface of the first plate. While the use of bending strips is less expensive than welding, a bending strip produces localized stress loading, which may compromise gasket sealing effectiveness over time. Further, the edges of the bending strip are unprotected. Therefore, the bending strip may become accidentally dislodged from the hole or otherwise damaged. In addition, the bending strips are often have limited effectiveness in gaskets that are subject to high frictional forces because the frictional forces cause buckling and sliding of the metallic plates, thereby resulting in the bending strips becoming partially disengaged from the first plate. Once again, sealing effectiveness is potentially compromised.
SUMMARY OF THE INVENTION
The present invention is directed to a snap-fit attachment element for laminating multiple metallic gasket layers together in a multi-layered sealing gasket.
The sealing gasket has at least two metallic gasket layers. A first metallic gasket layer includes at least one pre-blanked first aperture having a plurality of fingers extending radially inwardly from a peripheral edge of the first aperture. A second metallic gasket layer includes at least one second aperture and a supporting member formed on a peripheral edge of the second aperture. The supporting member extends upwardly from a first surface of the second gasket layer. The supporting member is preferably formed in a stamping operation such that the supporting member is integrally formed with the second metallic gasket layer. The supporting member includes a base portion and a closed end portion with the base portion connecting the supporting member to the second metallic gasket layer. At least two slots for receiving the fingers of the first metallic gasket layer are formed in the base portion of the supporting member. Preferably the slots are cut into a section of the second metallic gasket layer prior to the stamping operation so as to insure proper slot positioning.
To laminate the metallic gasket layers together, the first and second metallic gasket layers are arranged in an overlying manner such that the first aperture of the first metallic gasket layer is aligned with the supporting member of the second metallic gasket layer and the fingers are aligned with the slots. A laminating tool is then brought into contact with a first surface of the first metallic layer. The laminating tool has an engaging portion and a flexing portion that has a length slightly greater than the length of the engaging portion. The flexing portion elastically flexes the fingers to permit the supporting member of the second gasket layer to be extend through the first aperture of the first metallic gasket layer. Simultaneous with the flexing action, the engaging portion moves the first metallic layer into face-to-face contact with the second metallic layer. When the supporting member has extended through the first aperture, the fingers matingly engage the corresponding slots, disposing distal ends of the fingers into a chamber formed by the closed end portion and the base portion of the supporting member, thereby permanently laminating the first and second metallic gasket layers together without welding or the use of any additional fasteners. Further, as distal ends of the fingers are disposed within the chamber, the fingers are protected against possible damage, thereby insuring that the first and second metallic gasket layers do not become accidentally dislodged.
REFERENCES:
patent: 350020 (1886-09-01), Shipman
patent: 1320496 (1919-11-01), Roth
patent: 1607145 (1926-11-01), Anderson
patent: 3367809 (1968-02-01), Soloff
patent: 4456644 (1984-06-01), Janz et al.
patent: 4822671 (1989-04-01), Carper et al.
patent: 5084324 (1992-01-01), Schirmer
patent: 0588049 (1947-05-01), None
Dana Corporation
Knight Anthony
Peavey E
Rader & Fishman & Grauer, PLLC
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