Seal for a joint or juncture – Seal between relatively movable parts – Circumferential contact seal for other than piston
Reexamination Certificate
1998-08-21
2001-05-08
Knight, Anthony (Department: 3626)
Seal for a joint or juncture
Seal between relatively movable parts
Circumferential contact seal for other than piston
C277S909000, C277S576000, C277S572000
Reexamination Certificate
active
06227548
ABSTRACT:
This application corresponds to and claims priority under 35 U.S.C. § 119 with respect to German Application No. P 19736321.0 filed on Aug. 21, 1997, the entire content of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention generally relates to seals for use in connection with machine parts. More particularly, the present invention pertains to a valve shaft seal for use in machine parts that reciprocate relative to one another.
BACKGROUND OF THE INVENTION
EP-0 392 893 A1 discloses a valve shaft seal including a sealing ring attached by means of a sleeve-shaped holder on a valve shaft guide. The sleeve-shaped holder has a double-folded flange for supporting the valve spring on the side facing away from the sealing ring. A number of tabs engage an annular groove at the radially inside free end of the lowest flange part. This known holder has a complicated construction and is therefore difficult to manufacture. In addition, the tabs are provided at the end of the holder and so the holder easily tilts when relatively short seating areas are provided.
A need thus exists for a seal having a relatively simple and inexpensive holder which ensures a safe and flawless attachment and centering of the seal.
SUMMARY OF THE INVENTION
In light of the foregoing, one aspect of the present invention involves a valve shaft seal mounted on machine parts that reciprocate relative to each other. The valve shaft seal includes an elastomer sealing lip resting with a radial preload on the outer surface of the first machine part and a sleeve-shaped holder mounted on the second machine part. The holder includes a first section and a second section, with the first section of the holder carrying the sealing lip and the second section projecting axially beyond the sealing lip. The second section of the holder is outfitted with at least one inwardly extending projection that engages a recess formed in an outer surface of the second machine part.
The projection that is directed at an angle towards the inside and engages with a recess in the outer surface of the second machine part ensures a safe, form-fitting attachment of the holder and thus of the seal itself at the machine part. It also ensures a flawless centering of the seal relative to the machine part.
The projection axially fixes the seal and is preferably provided in the center area of the axially projecting second section of the holder so that a support that extends over a larger annular surface results, thus preventing angled orientation or canting of the seal.
The projection can be relatively simply formed by, for example, notching the cylindrical second section of the holder. Also, the corresponding recess in the second machine part is preferably formed as an annular groove, thus eliminating the need for peripheral alignment.
A softer adjustment of the radial characteristic force of the sealing lip can be achieved by providing the holder in the first section that carries the sealing lip with at least one axially extending slit. Such a slit can also be provided in the projecting second section of the holder to facilitate the sliding of the holder onto the machine part while also ensuring that the holder is pressed against the machine part. To further facilitate the sliding of the holder onto the machine part, the end of the holder facing away from the sealing lip can be expanded outwardly in a trumpet-shape.
According to another aspect of the invention, a valve shaft seal for use with first and second machine parts that reciprocate relative to each other includes an elastomer sealing lip that is adapted to rest with a radial preload on the first machine part and a sleeve-shaped holder adapted to be mounted on the second machine part, the holder including a first section and a second section, the first section of the holder carrying the sealing lip and the second section projecting axially beyond the sealing lip, the holder in the second section being provided with at least one inwardly extending projection that is adapted to engage a recess provided in an outer surface of the second machine part.
Another aspect of the invention involves a seal for providing a seal in connection with machine parts that reciprocate relative to each other. The seal includes a sleeve-shaped holder and a sealing lip, with the sealing lip being mounted on the holder and extending inwardly for resting on a first machine part while a portion of the holder extends beyond the sealing lip for being mounted on a second machine part. A portion of the holder is provided with at least one inwardly extending projection for engaging a recess provided in an outer surface of the second machine part.
REFERENCES:
patent: 4773363 (1988-09-01), Stritzke
patent: 4811703 (1989-03-01), Rericha et al.
patent: 4909202 (1990-03-01), Binford
patent: 4947811 (1990-08-01), Binford
patent: 1 899 855 (1964-09-01), None
patent: 24 44 792 (1976-04-01), None
patent: 0 392 893 (1990-10-01), None
patent: 0 405 750 (1991-01-01), None
Hans Deuring, Ventilschaftdichtringe und ihr Langzeitverhalten in Otto- und Dieselmotoren MTZ Motortechnische Zeitschrift, 43 (1982) 12.
Burns Doane Swecker & Mathis L.L.P.
CR Elastomere GmbH
Knight Anthony
Peavey Enoch E
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