Metal working – Means to assemble or disassemble – Coupling to conduit
Reexamination Certificate
1999-11-05
2001-03-13
Crane, Daniel C. (Department: 3725)
Metal working
Means to assemble or disassemble
Coupling to conduit
C029S252000, C029S283500
Reexamination Certificate
active
06199254
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to swaging tools for use with swage fittings, and more particular to a swaging tool for swaging axially swaged fittings.
2. Description of the Related Art
Fittings of various types are commonly used to couple tubes and pipes for a variety of applications. For example, in the aerospace industry, swage fittings couple hydraulic lines, fuel lines, and the like used to convey fluids in aircraft and other vehicles. Swage fittings also couple pipes, tubes, and conduits (hereinafter collectively “pipes”) that transport fluids in the marine, petroleum, and chemical industries. The coupling generally involves inserting pipe ends into a cylindrical sleeve of the fitting, and then swaging the fitting to the pipe using a swaging tool, to provide a fluid-tight or hermetic seal between the pipes. The swaging operation, generally requires the application of a radial force that deforms a portion of the pipe and the sleeve. The radial force may be applied directly to the fitting by the swaging tool, or indirectly through a swaging ring, which is moved axially over the fitting by the swaging tool to apply a radial force to the sleeve. Of interest in the present invention are the latter fittings, known as axially swaged fittings. The swage methodology is well known and is described in numerous patents, for example, U.S. Pat. Nos. 3,675,949 and 3,893,718.
Swaging tools are well known and their usefulness is well understood. Two examples of swaging tools for axially swaged fittings are described, for example in U.S. Pat. Nos. 5,398,394, and 5,592,726. Generally, the tools described in these patents have a first and second engagement members, which cradle the ring and/or the sleeve of the fitting while axially moving one engagement member towards the other to swage the fitting. The engagement members are U-shaped members that contact only a portion of the fitting. Thus, the swaging tool tends to provide the majority of axial force along the contacted portion of the pipe, which tends to create a non-uniform force distribution over the ring. The non-uniform force distribution may cause the pipe to cock or deflect as the ring is moved over the sleeve. This may cause gaps in the joint. The effect of a gap in small bore pipe swaging applications, is typically negligible. However, the inability of the tools to provide a substantially uniform axial force over the non-cradled portion of a pipe becomes problematic in large diameter bore pipes. As a result, swaging techniques are not widely used in industrial applications requiring large diameter bore pipes, especially for pipes containing high pressure fluid flow, such as in the marine and offshore oil and gas industries.
Until now, improvements in swaging tools for large diameter bore, high pressure pipe applications have generally been seen as unnecessary since large bore pipes may be coupled together using welds, flange and bolt connections, and threaded engagements. Although these types of connections are commonplace, they have a variety of drawbacks, which make them high cost, high risk, and/or time consuming alternatives to the present invention. For example, welded pipe joints usually require additional pre- and post-weld preparations that are often expensive and time consuming, such as pipe end preparation, post weld grinding, non destructive inspection, and hydro-testing. Welded pipes have also been known to fail at weak spots in heat affected areas adjacent to the welds. Moreover, welding in the vicinity of potentially flammable fluids, such as fuel and oil, which may be used in the pipes or tubes, is inherently risky. Flanged and bolted connecting systems require that the pipe ends be flared prior to use which may be inconvenient, expensive, and time consuming. To create the joint, the flanges are bolted together with a gasket in between, to provide a seal. In many instances vibrations or other general usage may loosen bolts and cause leaks. Moreover, gaskets are prone to failure after time or are easily damaged, which is another source of leaks. Threaded systems require pipe ends to be threaded, which can be both time consuming and ineffective. Generally, an abundance of access space is necessary for using wrenches and the like to couple the threaded pipes. Typically, a sealant is used on the threads to fill gaps and prevent leaking. However, after a period of time, the sealant can deteriorate, which leads to leaking.
For the above reasons, a swaging tool is needed that can swage axially swaged fittings on large bore pipes, such as those used in high pressure applications.
SUMMARY OF INVENTION
The present invention provides a swaging tool for swaging axially swaged fittings on pipes, especially pipes of two inches or more in diameter. The present invention, as described in more detail below, provides a radially balanced axial force, for uniformly pushing a ring of a fitting over a sleeve of the fitting, to swage the fitting to a pipe. The swaging tool is designed to be light weight and small in size, but able to provide an efficient swaging force. Further, the swaging tool is compact, simple to use, low maintenance, and relatively inexpensive to manufacture.
A swaging tool in accordance with one embodiment of the present invention includes a tubular housing, having an inner surface, which defines a bore. The bore is configured to receive at least one pipe section having an axially swaged fitting placed thereon in preparation for swaging. Preferably, the housing may be split lengthwise into two opposed sections, such that when the two sections are brought together, the sections completely surround a portion of the pipe sections and the fitting. Each housing section has cylindrical holes, typically formed symmetrically and circumferentially on one end of each section. The cylindrical holes are each configured to hold a pusher assembly. The pusher assembly preferably includes a pusher connected to a source of hydraulic pressure, which when activated moves the pusher axially to provide the axial force necessary for swaging the fitting. The pushers are made to uniformly contact the ring with a substantially even force that moves the ring axially over the sleeve. The axial movement causes the ring to apply a radial force to the sleeve to swage the sleeve to the pipe section. When the swaging operation is complete, the hydraulic pressure is removed from the pusher. A spring or other biasing device within the housing retracts the pusher into the cylindrical holes.
In one aspect of the invention, a swaging tool includes a housing having an inner surface, a first end, a second end, and a bore therebetween. The bore is configured to receive a portion of a pipe. A plurality of pusher assemblies are disposed uniformly and circumferentially around the housing, typically in axial alignment with the bore. When the pusher assemblies are brought into contact with the fitting, the pusher assemblies provide an evenly distributed axial force to the ring.
In another aspect of the invention, a swaging tool includes a housing having a first housing section and a second housing section, an inner surface, a first end, a second end, and a bore therebetween. The bore is configured to receive a portion of a pipe for swaging. A plurality of pusher assemblies are disposed uniformly and circumferentially around the bore in the housing. Each housing section includes an equal number of the pusher assemblies, such that when the pusher assemblies are brought into contact with the fitting, the pusher assemblies provide an evenly distributed axial swaging force to the fitting.
In another aspect of the present invention, a system for providing a swaging force includes a fitting, which has a sleeve and a swaging ring. Advantageously, the sleeve includes a deformable stepped portion. Also provided are a plurality of pusher assemblies disposed circumferentially in a housing to provide an evenly distributed force to axially move the swaging ring over the sleeve and thereby deform the stepped portion.
The two ho
Crane Daniel C.
Lopez Theodore P.
Mechl LLC
Skjerven Morrill & MacPherson LLP
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