Internal-combustion engines – Valve – Packing
Reexamination Certificate
2000-01-12
2001-08-07
Kamen, Noah P. (Department: 3747)
Internal-combustion engines
Valve
Packing
C277S502000
Reexamination Certificate
active
06269787
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to rocker cover gaskets and valve assemblies. More particularly, the present invention relates to a rocker cover gasket having integral valve stem seals for use in connection with a valve assembly for an internal combustion engine.
BACKGROUND OF THE INVENTION
A valve assembly for an internal combustion engine generally includes a valve spring and a valve seal having a retainer. Before the valve spring and the retainer fit into place, a valve seal is usually positioned over a valve stem. Valve stem seals control the amount of oil allowed between a valve stem and a valve stem guide. The seal functions in the manner of a positive seal or umbrella seal to prevent oil from flowing down the valve stem into the combustion chamber. The spring, which normally acts to keep the valve closed, is held in place by an individual retainer that is secured onto the valve stem. Such retainers typically prevent the valve spring from wearing into the engine head surface. A rocker cover gasket is separately provided to further insure against lubricant flowing into the combustion chamber. However, individual valve stem seal assemblies and rocker cover gaskets are undesirable due to increased assembly time and increased likelihood of manufacturing nonconformaties.
Another known type of valve seal assembly includes a rocker cover sealing member having coil seal members and bolt seal members connected together in series. The coil seal members are positioned on the outermost ends of the rocker cover sealing member and are arranged in a straight line in series on a single blank to correspond to ignition coil mounting holes. A narrow connection member secures the coil seal members together. However, this type of known rocker cover sealing member is undesirable as there is no means for compensating for self-alignment and tolerance problems. Further, there is no mechanism for selective removal of individual valve stem seals in the event of wear or failure of an individual valve stem seal.
Accordingly, there exists a need for an improved combination of a rocker cover gasket having integral valve stem seals. More particularly, there exists a need for a rocker cover gasket having multiple integral valve stem seals that is easy to produce, reduces the number of engine components, and makes the components that are used easier to handle and assemble with respect to a particular engine head configuration.
SUMMARY OF THE INVENTION
The present invention recognizes the limitations associated with currently available multi-seal assemblies and the production of such assemblies. The present invention provides an assembly that includes a rocker cover gasket having individual valve seals connected into a single assembly unit.
Rather than providing individual seals for each valve stem, a molded assembly can be used to seal all of the valve stems on a head of an engine. The assembly can be designed for a particular engine head with specific valve guide spacing having various angles. Further, such a rocker cover gasket/valve stem seal assembly will generally function to hold or retain the rubber portion of the individual seals and to act as a type of valve spring washer to prevent the valve spring from wearing into the head surface of an engine.
The present invention provides several advantages over conventional valve assemblies including, improved functionality, ease of manufacture, and convenient implementation and use. For instance, by forming a single rocker cover gasket assembly comprised of a plurality of integral valve stem seals, the number of component parts in an engine can be reduced, thereby streamlining the assembly process. Moreover, the rocker cover gasket assembly of the present invention may be tailored to specific engine head configurations to further improve the assembly process. Also, if desired, the rocker cover gasket assembly can be formed to include one or more handle portions, thereby making the assembly easier to handle and assemble in connection with a valve assembly.
In accordance with a preferred embodiment of the invention, a one-piece rocker cover gasket assembly is provided that is suitable for use in connection with a valve assembly for an internal combustion engine. The rocker cover assembly includes a molded structural plastic carrier with elastomeric gasket material molded around a peripheral edge of the carrier such for increased sealing effectiveness. A plurality of valve stem seals are integrally connected to the carrier by a plurality of carrier arms. By integrally connecting the carrier to the valve stem seals, a single gasket assembly is formed having the advantage of serving as a gasket that properly positions valve stem seals to permit ease of handling and reducing assembly time and inventory control costs.
In another preferred embodiment, rocker cover gasket assembly may be further provided with optional connectors, the connectors being used to connect or link one valve stem seal to another to form a type of linkage or web of valve stem seals. The connectors add a degree of rigidity to the assembly to insure proper placement of the valve stem seals in relation to the carrier. The connectors may be flat or curved to add a degree of flexibility to the gasket/seal assembly to compensate for tolerance and alignment difficulties.
Preferably, the ends of each connector and carrier arms that are adjacent to each valve stem seal are each provided with a thinned portion. The thinned portions are deformable to permit selective removal of individual valve stem seals from the carrier in the event of a failure or excessive wear of the valve stem seal. Optional pads or handles may also be incorporated on the connectors, or on the carrier to facilitate handling of the rocker cover gasket assembly or to serve as sprues during molding of the gasket.
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patent: 5775284 (1998-07-01), Kirchner et al.
patent: 6123054 (2000-09-01), Netzer
Dana Corporation
Huynh Hai
Kamen Noah P.
Rader & Fishman & Grauer, PLLC
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