Pipe joints or couplings – Packed – Sleeve
Reexamination Certificate
2000-01-18
2001-12-11
Browne, Lynne H. (Department: 3629)
Pipe joints or couplings
Packed
Sleeve
C285S369000, C285S104000
Reexamination Certificate
active
06328352
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pipe coupling for connecting pipes having unprofiled free end portions that face one another. The pipe coupling includes just one clamping clip that can be moved into the clamped position by a tensioning device, thereby reducing the diameter of the clip. The clamping clip is interrupted in the circumferential direction to permit its diameter to be reduced during the clamping process and to permit its diameter to be increased to insert further components of the pipe coupling into the clip. An annular sealing ring corresponds to each pipe and is made of a deformable material so that it may press on the circumference of the free end portion of the respective pipe. A retention device extends over the major part of the circumference of the annular sealing rings.
2. Discussion of the Related Art
U.S. Pat. No. 3,116,078 to Scherer discloses a pipe coupling that includes a collar 18 of rubber or rubber-like material. Collar 18 bridges the gap between the mutually facing ends of two pipes that have been introduced into the pipe coupling. The radially inner surface of the collar comes into contact with the fluid flowing through the pipes. If the pipe coupling is used for pipes that carry high temperature or aggressive fluids (e.g., the exhaust gases in exhaust pipes, especially those of an internal combustion engine), the sealing collar must be produced from an expensive material that can withstand these types of fluids for a sufficient length of time. Conventional elastomers are unsuitable for this purpose. Because the ends of the pipes are not always placed directly against one another, but are often axially spaced a relatively large distance apart, a relatively large amount of expensive sealing material is required in the production of the sealing collar.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a pipe coupling that uses less material for the sealing device, ensures a high leak tightness of the joint and also provides a longer service life for the sealing device, especially at relatively high temperatures.
This and other objects are achieved in accordance with a currently preferred exemplary embodiment of the present invention by using a sealing device that comprises two sealing rings, each of which is assigned to one of the pipes. An annular sleeve is disposed radially within the retention device. The sleeve has end portions that are bent obliquely outwardly toward the sealing rings. An inner surface of each of the end portions rests against the axially inner face of one of the sealing rings. A retention device has two radially inwardly open, circumferentially extending grooves of approximately V-shape in cross-section. The V-shaped grooves are interrupted to match interruptions in the retention device. An inner surface of one side wall of each of the grooves rests against the outer surface of the mutually facing sides of the bent axial end portions of the sleeve. In a clamped position, an inner surface of the other side wall of each groove exerts an axial force on the axially outer face of each of the sealing rings.
Thus, in accordance with this exemplary embodiment, less sealing material is required than conventional pipe couplings, regardless of the axial distance between the free axial ends of the connected pipes. The sealing rings are, to a large extent, enclosed and, therefore, do not to any great extent come into contact with the fluid in the pipes. Thus, a relatively large degree of freedom is permitted in choosing of the sealing ring material. Moreover, an axial force is exerted on the faces of the sealing rings as the clip is clamped. The axial force causes the sealing material to yield radially inwardly so that it is pressed, with a corresponding high pressure, against the outer surface of the pipes. The leak tightness of the joint is, therefore, guaranteed, even when the internal pressures in the pipes are high. Thus, the pipe coupling in accordance with the present invention is particularly suitable for exhaust pipes of internal combustion processes, especially internal combustion engines in motor vehicles.
A tapered cover ring is preferably disposed between the inner surface of the other side wall of each of the grooves and the axially outer face of the sealing rings. The axially outer faces of the sealing rings are directed away from one another toward opposite axial ends of the clip. The tapered cover rings ensure that, even in the region of one or more interruptions in the circumference of the clip, clip strap and/or the retention device, the sealing rings are to a large extent protected even on their axially outer faces from aggressive fluids (e.g., atmospheric oxygen and/or water-containing road salt from melted snow), which exhaust pipe systems of motor vehicles are frequently exposed to.
Radially outside of the sealing ring, an axial end portion of the tapered cover ring axially overlaps an axial end portion of the bent portion of the sleeve. Thus, the sealing rings are protected from aggressive fluids over their entire circumference by these overlapping axial end portions, even on the outer radial side of the sealing rings. The overlapping end portions also facilitate centering of the sleeve and cover rings during the assembly of the pipe coup ling . The radially inner surface of these axial end portions also act as a stop to limit the axial compression of the sealing rings.
The retention device has two radially inward projecting corrugation peaks at each of its axial end portions. The mutually adjacent side walls of the peaks, respectively, form the side walls of one of the V-shaped grooves. Thus, the V-shaped grooves are formed from a simple design. In an alternate embodiment, the clip itself can form the retention device by having two radially inward projecting corrugation peaks at each of its axial end portions, thereby eliminating the retention device as a separate part.
Alternatively, the retention device can be in the form of a collar that is interrupted in the circumferential direction and is disposed radially within the clip. This type of collar is easy to form from sheet material that is resistant to aggressive fluids. For example, the sheet material can be sheet metal, which is a thin-walled material that nevertheless withstands high clamping forces.
A generally conical retaining ring is disposed between the axially outer side wall of each of the axially outer corrugation peaks and each of the radial flanges of the clip. The flanges are bent radially inwardly towards an axial center line of the pipe coupling at each axial end of the clip. Each of the flanges have at least one interruption. The retaining ring has on its radially inner rim claws for engaging into the pipe material. An axial inner surface rests against the axially outer side wall of the axially outer corrugation peak of the radially inward projecting corrugation peaks in the retention device. The retaining rings increase the axial load bearing capacity of the pipe joint at high internal pressures. Under increasing higher pressure, the retaining rings straightening up (i.e., they move to a more radial direction), thereby digging ever more firmly into the pipe material.
An axially outer side wall of each of the axially outer corrugation peaks merges into a radially outwardly projecting flattened corrugation peak. The generally conical retaining ring rests in an axially outer bend of the radially outwardly projecting corrugation peak. With this construction, the retaining rings increase the axial load bearing capacity of the pipe joint at high internal pressures. To make the clip more flexible, the flanges on the axial ends of the clip can be omitted.
The retention device preferably has at least one length compensation corrugation to compensate for a change in the length of the retention device during the clamping of the clip.
The length compensation corrugation preferably includes radial apertures. Radial apertures increase the flexibility of the length compensatio
Geppert Helmut
Scheit Peter
Bochna David E.
Browne Lynne H.
Darby & Darby
Rasmussen GmbH
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