Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
1998-11-18
2001-03-20
Arola, Dave W. (Department: 3627)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S890140, C285S093000, C285S382000
Reexamination Certificate
active
06202284
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fitting for connecting pipes that carry fluid or gas, and more particularly, a fitting that can be connected to a pipe by using a fluid powered sizing apparatus.
2. Description of the Prior Art
Fittings for connecting the ends of pipes are old in the art. The earliest method of fitting two pipes together involved a simple member with an outside diameter that is larger than the pipe to be inserted, creating a snug fit between the two pipes as shown in U.S. Pat. No. 2,121,558. The telescopically inserted pipe could then be either glued are soldered to form a liquid or gas tight seal. The problem with this early design was the inconvenience of using either glue or solder. Further, these pipe fittings did not prove to be adequate for high pressures (above 500 psi).
The earlier pipe fittings were improved upon by creating a member with a complex inner surface that contacted the telescopically inserted pipe. This complex surface consists of such designs as curved grooves as in U.S. Pat. No. 5,080,406, or “teeth” and a lock-ring as in U.S. Pat. No. 4,482,174, or annular grooves as in U.S. Pat. No. 5,452,921. Each of these fittings are designed to operate by inserting a pipe within the complex inner surfaced member and swaging the outer surface of the member. The drawback to these designs is that the inner grooves and teeth create a deformation in the pipe that is inserted. This creates areas of high stress concentrated at specific points in the pipe. It is these high stress areas that are major factors in the incidence of failure in pipe fittings. Furthermore, in order for these fittings to work properly, they must be large and relatively heavy. These characteristics make the prior art fittings undesirable for smaller high pressure fittings.
Other pipe fitting devices can incorporate an “O” ring and adhesives to help form a tight seal as in U.S. Pat. No. 4,330,924. However, this device is also swaged in such a manner as to deform the pipe member that is within the outer fitting member. Also, this and other designs are not as versatile as desired due to the dual nature of the design—both the female (fitting) and male (pipe) portions of the device are designed to work together exclusively. This limits the use of the joint to pipes that are specifically tailored to fit the joint. Thus, while there have been improvements in pipe fittings from the earliest inventions, there is still a need for easier to use fittings. In particular, there is a need for improved fittings for commercial use where qualities such as weight, durability, and low cost are critical factors.
SUMMARY OF THE INVENTION
The present invention consists of a metal pipe fitting, which comprises a generally cylindrical sleeve having an exterior surface and an interior surface. The sleeve has a proximate end and a distal end with the proximate end forming a mouth opening for receiving a mating length of metal pipe the fitting.
Preferably, the sleeve has a circumferential groove formed within the interior surface between the proximate and distal ends, and a seal ring located within the circumferential groove. There is at least one inspection divet which penetrates the exterior surface of the sleeve to the interior thereof to reveal the exterior of the mating length of metal pipe for verifying the proper insertion of the metal pipe. The sleeve narrows in internal diameter in the direction of the distal end to form a positive stop for the mating length of metal pipe to properly locate the mating length of metal pipe at a desired position within the pipe joint.
The seal ring located within the circumferential groove of the sleeve is formed of a resilient material, including but not limited to such materials as polytetrafluoroethylene. There is at least one circumferentially raised portion on the interior and corresponding exterior of the sleeve. The exterior surface of the sleeve is formed in a preselected size which is adapted to be received within the mating jaws of a sizing apparatus. The mating jaws are selectively sized to apply a uniform inwardly directed circumferential pressure to at least a portion of a length of the exterior surface of the sleeve to crimp the sleeve about the mating length of pipe and form a pipe joint.
The metal pipe fitting can be in a T-shaped form with a pair of diametrically opposing mouth openings and a third mouth opening which is arranged at perpendicular position to the diametrically opposing mouth openings, each opening arranged to receive a mating length of pipe. The pipe fitting is formed from a metal including but not limited to copper, steel, stainless steel, and brass.
This invention is also a method of forming a pipe joint comprising the insertion of a mating length of pipe within the mouth of the fitting described above until the mating length of pipe is properly located against the positive stop. Pressure is then applied from a sizing apparatus to the exterior surface of the sleeve to uniformly reduce the sleeve's internal diameter and engage the mating length of pipe within the interior surface of the sleeve.
An object of the present invention is to provide a high pressure fitting for use in a piping joint that allows convenient joining of two ends of a pipe at a variety of angles using a sizing apparatus.
Another object of this invention is to create an easy to use and durable pipe joint for creating a continuous pipe system for transporting liquids and/or gases.
Another object of this invention is to create a pipe joint using the fitting that can withstand high pressure gases or liquids.
Another object of this invention is to form a pipe joint that does not deform the pipe inserted within the fitting upon application of the sizing apparatus.
Another object of this invention is to provide an improved pipe joint for use in the plumbing construction industry.
Additional objects, features and advantages will be apparent in the written description which follows.
REFERENCES:
patent: 2121558 (1938-06-01), Coe et al.
patent: 3244441 (1966-04-01), Caudle
patent: 3596939 (1971-08-01), Gibson
patent: 4330924 (1982-05-01), Kushner et al.
patent: 4482174 (1984-11-01), Puri
patent: 4666190 (1987-05-01), Yamabe et al.
patent: 5080406 (1992-01-01), Hyatt et al.
patent: 5090743 (1992-02-01), Obering
patent: 5452921 (1995-09-01), Hyatt
patent: 5484174 (1996-01-01), Gotoh et al.
patent: 511527 (1939-08-01), None
Arola Dave W.
Gunter, Jr. Charles D.
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