Seal for a joint or juncture – Seal between fixed parts or static contact against... – Contact seal for other than internal combustion engine – or...
Reexamination Certificate
1999-08-02
2001-09-18
Knight, Anthony (Department: 3626)
Seal for a joint or juncture
Seal between fixed parts or static contact against...
Contact seal for other than internal combustion engine, or...
C277S650000, C277S616000, C277S637000
Reexamination Certificate
active
06290240
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a grommet cup packing made of elastomeric material for hydraulic apparatus.
BACKGROUND OF THE INVENTION
These packings are used to form a seal between two cooperating parts of a hydraulic apparatus, primarily faucets and cartridges for faucets. The cup packing is inserted in a seat that is recessed in one of the two parts between which a seal must be established, and it is forced into contact with the other part. The force is often applied by a spring housed inside the cup packing, but it can also be applied by means of diverse or diversely arranged members or by the elasticity of the elastomeric material comprising the cup packing. To establish the best possible hydraulic seal these packings should be made of an elastomeric material that has a high degree of elastic yield. As a rule, conventional cup packings have a circular cross-section.
The conventional and known cup packings have serious disadvantages. For both technical and regulatory reasons hydraulic apparatus must be able to resist high pressures which, according to some standards, attain 50 bar and even 120 bar. If the cup packings are comprised of elastomeric material under high pressures, and especially in the case of pressure surges, they can become deformed and can even burst. This means that such packings must be made with relatively rigid elastomeric material which is unable to establish the best possible seal. This phenomenon is also present when the packings are installed under operationally static conditions.
When such packings are used under operationally dynamic conditions, i.e., when they must establish a seal between reciprocally movable parts, there is yet another disadvantage. When one of the two parts, between which the cup packing establishes a seal, is shifted with respect to the other part in which the cup packing is seated, then the packing tends to be dragged, due to friction, and is deformed. If the movable part is a shutter that has passage openings which must be open or closed during displacement, then the deformation of the packing modifies the relative positions in which the passage openings are controlled, and if said deformation is excessive it impairs the precision of the shutter's operation and may even actually jeopardize the proper closing, for example, of a faucet.
It has been proposed to rigidify a cup packing by inserting a bushing made of rigid material such as a plastic. However, this procedure has not proven to be sufficiently effective due to the fact that the pressure can be transmitted to the interface between the cup packing and the inserted bushing, and it can thus act on the packing itself causing the above discussed disadvantages.
One purpose of this invention is to provide a cup packing consisting of a relatively yielding elastomeric material which would be able to establish a good seal and which will be able to resist high pressures and pressure surges.
Another purpose of this invention is to provide a cup packing which would be particularly suitable for dynamic operation due to the fact that it does not undergo excessive deformation due to by the displacement of the parts between which the seal is established.
Yet another object of the invention is to provide a cup packing which can be formed with a noncircular cross-section.
SUMMARY OF THE INVENTION
These objects are attained according to this invention by virtue of the fact that the packing has a composite structure. This composite structure is comprised of an elastomeric material (which can have considerable yielding capacity) in the portions intended to establish a seal and of a rigid or semirigid material (such as a suitable plastic material or a metallic material) corresponding to a core that is at least partly incorporated in the elastomeric material of the packing.
In this composite structure the elastomeric material only functions to establish the hydraulic seal. It is thus practically relieved of all of the mechanical resistance functions of the packing which are entirely or almost entirely performed by the incorporated core, which takes the stresses to which the packing is subjected, both under static conditions and under dynamic conditions. This means that one can separately design with different criteria, especially with regard to the choice of materials, the two parts of the packing's structure. The packing of the instant invention has a high degree of sealing due to the choice of a sufficiently yielding elastomer and a high degree of resistance to deformations due to the choice of appropriate shapes and composition of the core.
Preferably, the core which is incorporated in the elastomeric material is provided with anchoring means that can secure the elastomeric material to the core itself.
In particular, the core can consist of a portion that extends axially, having a cross-section that substantially corresponds to the cross-section of the packing, from which laterally extend sections of flange that at least partly extend radially in the elastomeric material.
The packing of this invention is preferably made by injecting an elastomeric material in the fluid state into a mold so as to incorporate a rigid or semirigid core, and then cross-linking the elastomeric material that constitutes the packing.
In contrast to known and conventional cup packings, the packing of this invention need not have a circular cross-section. The packing can considerably diverge from this usual circular shape, providing that the seat in which it is seated has a corresponding shape. It is also possible to provide different shapes to the portion of the packing that is seated in a seat of one of the two parts between which the seal is established and to the portion of the packing that provides the seal.
These and other features, purposes and advantages of this invention will be apparent from the following description of some of the embodiments illustrated in the attached drawings.
REFERENCES:
patent: 2062186 (1936-11-01), Mittelman
patent: 2069212 (1937-02-01), Buffington
patent: 2345515 (1944-03-01), Tweedale
patent: 4298203 (1981-11-01), Hölzer et al.
patent: 4538819 (1985-09-01), Wagner et al.
patent: 4674756 (1987-06-01), Fallon et al.
patent: 5004650 (1991-04-01), Ashizawa et al.
patent: 5011162 (1991-04-01), Jelinek
patent: 5518027 (1996-05-01), Saiki et al.
patent: 6116279 (2000-09-01), Pawelzik et al.
Adusei-Poku Kwadjo
Doigan Lloyd D.
Knight Anthony
Masco Corporation of Indiana
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