Seal for a joint or juncture – Seal between fixed parts or static contact against... – Contact seal between parts of internal combustion engine
Reexamination Certificate
1999-07-09
2001-11-20
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
C277S595000, C277S612000, C277S647000, C277S649000
Reexamination Certificate
active
06318732
ABSTRACT:
This invention is concerned with a gasket of the type which is adapted when clamped between two bodies to seal the gap between the bodies around a chamber or passage jointly defined by the bodies. Such a gasket may be used, for example, for sealing the gap between flanges at the ends of pipes. The present invention is also concerned with two bodies that incorporate a gasket and a method of sealing two bodies with a gasket.
Gaskets require to be resilient in order to achieve a seal. In some gaskets, the resilience is achieved by using inherently resilient material such as rubber or cork and, in other gaskets, the resilience is achieved by utilising springy metal which resists being bent out of its initial shape. This invention is concerned with the latter type of gasket which comprises a sealing member which forms a closed loop extending around a hole which corresponds to the chamber or passage. Such gaskets are often in the shape of an annular ring but may have other shapes. Accordingly, the term “ring” is used herein to include a continuous band surrounding a hole of any shape.
Known gaskets made of springy metal have sealing members which have generally C or V-shaped transverse cross-sections (see U.S. Pat. No. 4,877,272 for a V-shaped cross-section). The cross-section comprises two arms which project either inwardly or outwardly of the hole, the arms being adapted to each resiliently engage one of the bodies to form a seal around said hole. In this type of gasket, the sealing force is achieved by deformation of a single piece of metal which bends sharply between its lines of engagement with the bodies against which the gasket seals. Because the single piece of metal has to bend sharply, there is a danger that cracking may occur when the clamping force is applied.
GB 1 041 181 (BTR) and GB 1 434 492 (Ford) describe annular gaskets that form a seal between two bodies. When the bodies are tightened to their limit the annular gaskets, which previously comprised springy arms spaced from each other, are clamped together tightly along their complete co-extent to form parallel arms that abut the bodies and abut each other. Thus when the bodies go from being spaced apart from their limit position to the limit position the seal provided goes from being a substantially linear seal around the bodies to a seal which has an extent radially outwardly of the bodies over the co-extent of the bodies and the arms.
In the limit position the arms may have been bent beyond their useful working range where the spring force of the arms exerts an optimum sealing pressure on the bodies. Alternatively or additionally, to keep the arms operating in their optimum range, the bodies will have to initially engage the arms at a position where the bodies are extremely close together. In the limit position the force exerted on the springy arms may be such that the arms crack when the clamping force is applied or when an excessive clamping force is applied. Furthermore, the seal provided by the arms contacting each other along their complete co-extent is not as satisfactory as a substantially linear contact where the arms remain spaced apart. In addition, in the limit position where the arms are in contact, the pressure of fluid in the two bodies can not urge the parts into further sealing engagement with each other.
It is an object of the present invention to attempt to overcome at least some of the above described disadvantages.
It is another object of the present invention to provide a gasket in which spring metal is used to provide the sealing force, the gasket having a reduced risk of cracking.
According to one aspect of the present invention in a gasket adapted when clamped between two bodies around a chamber or passage jointly defined by the bodies, the gasket forms a ring extending around a hole which corresponds to the chamber or passage, the gasket comprises a first sealing member and a second sealing member both made of springy metal, and a compression limiting stop, the first sealing member having an arm portion projecting from the compression limiting stop, the arm portion of the first sealing member being adapted to resiliently engage one of said bodies to form a seal therewith at a location spaced from the stop, and the second sealing member having an arm portion projecting from the stop, the arm portion of the second sealing member being adapted to resiliently engage the other of said bodies to form a seal therewith at a location spaced from the stop, the first and second sealing members being arranged to resiliently engage their respective bodies to form a seal therewith at a location spaced from the compression limiting stop when both of the bodies engage the stop.
The first and second sealing members may be arranged to be spaced from each other at the location that they sealingly engage their respective bodies when both of the bodies engage the stop.
The free ends of each arm may be arranged to resiliently engage their respective bodies to form a resilient seal therewith.
A location spaced from the ends of the arms may be arranged to engage the respective bodies to form a resilient seal therewith.
A clamping member may be arranged to hold the first and second sealing members in an overlying relationship. The clamping member can be made of thicker material which can resist cracking better than a springy metal. The clamping member may comprise the compression limiting stop. The clamping member may press said first and said second sealing members together so that a seal is formed between them. The clamping member may be formed from sheet metal and have a generally C-shaped transverse cross-section comprising two legs between which the sealing members are received, the legs engaging the sealing members.
The compression limiting stop may be arranged to transmit forces between the bodies, when both bodies engage the stop, through a portion that is separate from the first and second sealing members.
The first and second sealing members may be welded together.
The compression limiting stop may comprise a first member adapted to extend around a hole which corresponds to the chamber or passage arranged to engage one of the bodies and a second member adapted to extend around a hole which corresponds to the chamber or passage arranged to engage the other of the bodies. The first and second members may be spaced from each other. The first and second sealing members may extend at least partially through the first and second members of the compression limiting stop. The first and second members of the compression limiting stop may be welded to the first and second sealing members.
The pressure of fluid within a chamber of passage may be arranged to bias the arm portions further into engagement with their respective bodies to further enhance the sealing effect of the gasket, and may enhance that sealing effect even when the bodies engage the compression limiting stop.
A first sealing means comprising the first and second sealing members may extend inwardly of the compression limiting stop and second sealing means also comprising first and second sealing members as claimed in any preceding claim may extend outwardly of the compression limiting stop.
According to another aspect of the present invention in two bodies that incorporate a gasket clamped between them to seal the gap between the bodies around a chamber or passage jointly defined by the bodies, the gasket forms a ring extending around a hole which corresponds to the chamber or passage, wherein the gasket comprises a first sealing member and a second sealing member both made of springy metal, and a compression limiting stop, the first sealing member having an arm portion projecting from the compression limiting stop, the arm portion of the first sealing member resiliently engaging one of the bodies to form a seal therewith at a location spaced from the stop, the second sealing member having an arm portion projecting from the stop, the arm portion of the second sealing member resiliently engaging the other of the bodies to form a seal therewith at a
Atkinson Alan William
Bond Stephen Peter
Currie Anthony Russel
Hoyes John Robert
Mowvley Peter George
Flexitallic Investments, Inc.
Haynes and Boone L.L.P.
Knight Anthony
Montgomery John W.
Peavey Enoch
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