Pipe joints or couplings – Particular interface – Interlocked or overlapped
Reexamination Certificate
1999-06-21
2001-01-09
Arola, Dave W. (Department: 3627)
Pipe joints or couplings
Particular interface
Interlocked or overlapped
C285S351000, C285S382500, C029S523000
Reexamination Certificate
active
06170888
ABSTRACT:
TECHNICAL FIELD
This invention relates to conduit connectors. Specifically, this invention relates to a joint for connecting a tube and a fitting body and the method of forming the joint.
BACKGROUND ART
Many types of conduit couplings are known in the prior art. One category of conduit couplings includes tube fittings which are used to join a tube or similar conduit and a fitting body.
One variety of tube fittings includes compression fittings. Such fittings involve the use of ferrules, nuts and other component pieces for holding a tube in fluid tight connection with a fitting body. Tube fittings of this variety have drawbacks in that they include several components. Such multiple components add to the cost of the fitting. In addition, the assembly of such fittings requires several steps. The completion of these steps takes time which further adds to the cost of using such connectors. The use of several components and a multi-step assembly process also increases the chance of defects which can result in leakage or other types of failure.
Stake type fittings are also known in the prior art. Such fittings have the advantage of being low in cost and may be assembled at high production rates. Examples of prior art stake type tube fittings are shown in U.S. Pat. Nos. 3,930,928, 3,977,710, 4,200,314, 4,262,942, 4,330,144 and 4,450,618, all of which are owned by the assignee of the present invention.
While the prior art stake type tube fittings perform well, there is always a desire to improve fitting performance, increase production rates and to reduce cost.
Thus, there exists a need for a joint connection for joining a tube and a fitting body that is lower in cost, more resistant to leakage, is more rapidly assembled and has greater resistance to unwanted disassembly due to applied forces.
DISCLOSURE OF INVENTION
It is an object of the present invention to provide a joint for connecting a tube and a fitting body.
It is a further object of the present invention to provide a joint for connecting a tube and a fitting body that is a stake type joint.
It is a further object of the present invention to provide a joint for connecting a tube and a fitting body that may be assembled quickly and with automated equipment.
It is a further object of the present invention to provide a joint for connecting a tube and a fitting body that is fluid tight and which provides greater resistance to leakage at higher pressures.
It is a further object of the present invention to provide a joint for connecting a tube and a fitting body that is lower in cost to produce and assemble.
It is a further object of the present invention to provide a joint for connecting a tube and a fitting body that provides greater resistance to unwanted disassembly and breakdown.
It is a further object of the present invention to provide a joint for connecting a tube and a fitting body that may be configured in a manner that is tailored to the particular operating requirements of the system in which it is used.
It is a further object of the present invention to provide a method for forming a joint connecting a tube and a fitting body.
It is a further object of the present invention to provide a method for connecting a tube and a fitting body that may be carried out at high production rates using automated equipment.
It is a further object of the present invention to provide a method for connecting a tube and a fitting body that results in a joint that has increased resistance to leakage, increased resistance to unwanted disassembly and breakdown, and which may be configured in a manner that is tailored to the particular operating requirements of the system in which the joint is used.
Further objects of the present invention will be made apparent in the following Best Modes for Carrying Out Invention and the appended claims.
The foregoing objects are accomplished in a preferred embodiment of the invention by a joint which connects a tube and a fitting body. The joint is manufactured by a process which includes the step of axially extending a hollow tube into a bore in a fitting body. The bore in the fitting body is bounded by a generally annular bore wall. The bore wall includes a generally axially extending bead formation area. The bead formation area is radially disposed outwardly from the tube when the tube is first extended into the bore.
The process of forming the joint further involves engaging an inward end of the tube against a stop face supported on the fitting body in the bore. Thereafter, the tube is compressed axially inward. The compression of the tube in engagement with the stop face causes the sequential formation of at least two outwardly extending beads in the tube. The beads extend outwardly and engage the bore wall in the bead formation area. The engagement of the beads with the bore wall provides a fluid tight joint.
In one form of the invention, after formation of the beads within the bore a tool is axially extended through the fitting opening. The tool operates to axially compress the beads as well as to expand the bead material outwardly into stronger interference engagement with the bore wall. The tool is then withdrawn leaving a joint which is resistant to leakage as well as highly resistant to unwanted disassembly due to internal pressure or external axial or torsional forces.
In another form of the invention the tool which is extended into the bore to compress and radially expand the beads also forms a retaining ridge in the fitting body adjacent to the bore opening. The retaining ridge engages the compressed bead material to resist separation of the joint.
In another form of the invention the bore wall though generally annular, includes a plurality of axially extending serrations. The serrations engage the beads and provide added resistance to rotational movement of the tube relative to the fitting body.
Other forms of the invention include annular seals and other sealing structures which operatively extend between the tube and the bore to resist fluid leakage. Such seals may include combinations of annular o-rings, disc seals and sealing materials which are formed in place. The sealing structures are tailored to enable the joint to satisfactorily operate under various temperature and pressure conditions.
REFERENCES:
patent: 2685461 (1954-08-01), Ridenour
patent: 3787945 (1974-01-01), Pasek et al.
patent: 3930298 (1976-01-01), Ridenour
patent: 3977710 (1976-08-01), Ridenour
patent: 4200314 (1980-04-01), Ridenour
patent: 4262942 (1981-04-01), Ridenour
patent: 4330144 (1982-05-01), Ridenour
patent: 4450618 (1984-05-01), Ridenour
patent: 4805944 (1989-02-01), Reginaldo
patent: 4871199 (1989-10-01), Ridenour et al.
Arola Dave W.
Jocke Ralph E.
Universal Tubular Systems Inc.
Walker & Jocke
Wasil Daniel D.
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