Pipe joints or couplings – Particular interface
Reexamination Certificate
2000-02-01
2003-02-11
Sandy, Robert J. (Department: 3677)
Pipe joints or couplings
Particular interface
C285S373000
Reexamination Certificate
active
06517122
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to pipe fittings, and more particularly to a clamshell coupling system and method.
BACKGROUND OF THE INVENTION
Conduit systems are used in a number of industries and applications to form a passage(s) for communicating a media(s). For example, conduit systems are utilized in water and sewage plumbing systems; electrical wire and optic fiber conduit systems; hydraulic and pneumatic systems; as well as other devices and systems. The conduit system generally comprises a number of pipes that are connected together, or assembled, to form the conduit system. The pipe is often constructed from a plastic, such as rigid or plasticized polyvinyl chloride (PVC), and polyethylene. The pipe may be rigid or flexible, and is generally formed in relatively short lengths that must be joined together. In many applications a pipe coupling is used to join the pipes. Pipe couplings can be permanent or detachable. Conventional pipe couplings have several disadvantages. Many piping systems are “welded” together through a process called electro-fusion. This is an expensive and time consuming operation with many drawbacks. For instance, the melting points associated with pipes of different manufacturers may vary considerably thereby hindering the welding operation. Accordingly, skilled artisans are required to assemble piping components and the process must be adjusted continually as ambient temperature changes.
Conventional pipe couplings are often difficult to assemble and prone to failure. In addition, many do not form a tight seal between the pipe interior and ambient environment, thereby allowing the media to escape to the outside environment, or allowing the outside environment to contaminate the media. In general, conventional pipe couplings are difficult to install and assemble, thereby requiring expensive skilled artisans to construct the conduit system. Conduit systems provide an environmentally secure and protective passage for routing optic fibers from one location to another.
In one method of installation, a trench is dug and the pipe is inserted into the trench. A coupling may be used to attach additional pipes to the buried pipe and the construction process continues. In many instances, an obstacle, such as a roadway or the like, prevents a trench from being dug. In these instances, a small passage, or borehole may be excavated under the obstacle and the pipes and the associated couplings are pulled through the passage. The pulling action may create a longitudinal tension load between the couplings and their associated pipes. The pipes may be separated from their associated couplings when under an excessive longitudinal tension load. In many situations, the pipes and/or couplings are also rotated and pulled in order to get the pipes through a restricted passage. Rotating the pipes places a rotational load on the couplings and vice versa. The rotational load may also cause the tubular conduit to separate from the coupling.
SUMMARY OF THE INVENTION
Accordingly, a need has arisen in the art for an improved coupling. The present invention provides a clamshell coupling that substantially reduces or eliminates problems associated with prior systems and methods.
In accordance with one embodiment of the present invention, a coupling comprises at least one semi-tubular, longitudinal housing, having first and second ends which may be adapted to receive at least one section of conduit. The housing may include a first indented region forming a locking lug upon the exterior diameter of the housing. In one embodiment, a second semi-tubular, longitudinal housing, complimentary to the first housing, may be provided, having at least a second indented region forming a second locking lug upon an exterior diameter of the second housing. A locking mechanism including first and second protrusions which cooperate with the first and second locking lugs to couple the first and second housings at a first longitudinal joint, may also be provided.
In a particular embodiment, a hinge operable to couple the first and second housings at a second longitudinal joint may also be provided. In another embodiment, third a fourth indented regions associated with the first and second housings, respectively, may form third and fourth locking lugs on respective exterior diameters of the first and second housings. In this embodiment, a second locking mechanism having third and fourth protrusions which cooperate with the third and fourth locking lugs, respectively, to couple the first and second housings at a second longitudinal joint, may also be provided.
A restraint system may also be provided at an interior diameter of the first housing. In one embodiment, the restraint system may include at least one semi-circular insert disposed along the interior diameter. The insert may include a plurality of gripping teeth operable to engage the conduit when the conduit coupling is in an assembled position. In another embodiment, the restraint system may include a plurality of spikes extending from the interior diameter and operable to engage the conduit when the coupling is in an assembled position. In yet another embodiment, the restraint system may include at least one semi-circular gasket protruding from a notched opening within the interior diameter.
In a particular embodiment, the gripping teeth and/or spikes may extend toward a central portion of the interior diameter, and form an angle greater than 5 degrees with respect to a longitudinal central axis of the conduit coupling. In another embodiment, the gripping teeth and/or spikes may include respective points which extend approximately perpendicular to an axial central axis of the coupling. In still another embodiment, the points may extend toward an axial midpoint of the conduit coupling.
The present invention provides several technical advantages. For example, the coupling can resist very high longitudinal tension loads, as well as rotational loads. Thus, the coupling may be used in high load applications without the conduits becoming separated from the coupling. Accordingly, the cost and expense associated with constructing a conduit system are reduced.
Another technical advantage of the present invention is that the clamshell coupling is generally constructed from plastic materials that will not corrode. Accordingly, the operational life of the conduit system is longer, and the cost of the conduit system is reduced.
Still another technical advantage of the present invention is that the clamshell coupling can maintain a tight environmental seal between the clamshell coupling and the tubular members. Accordingly, the media within the conduit system cannot easily leak to the outside environment, and the outside environment cannot easily contaminate the media.
Yet another advantage is the couplings low profile that makes it easier to install in tight spaces and causes lower friction when pulling through a bore hole.
A further technical advantage of the present invention is that the clamshell coupling is easy to install and remove. Accordingly, the time and expense associated with constructing the conduit system are reduced.
Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions, and claims.
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Baker & Botts L.L.P.
Melwani Dinesh
Sandy Robert J.
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