Pipe joints or couplings – Serial,relatively movable portions – Serial diverse single flow path or line
Reexamination Certificate
1999-07-09
2001-02-13
Wilson, Neill (Department: 3627)
Pipe joints or couplings
Serial,relatively movable portions
Serial diverse single flow path or line
C285S355000, C285S390000, C285S423000
Reexamination Certificate
active
06186558
ABSTRACT:
BACKGROUND OF THE INVENTION
1) Field of the Invention
The field of this invention relates to pipe fittings and more particularly to an interconnecting male coupler and female coupler which are to be connected together in a liquid tight manner between a pair of pipe sections which are slightly axially spaced apart.
2) Description of the Prior Art
The use of pipe fittings for connecting together a pair of axially spaced apart pipe sections has long been known. In the laying of any liquid conducting pipe, generally the pipe sections come in prescribed lengths, such as twenty feet in length or any other custom required length. When laying of a length of pipe greater or lesser than standard available length, there is therefore required pipe fittings to connect together the joined pipe sections in a liquid tight manner. Normally, for reasons of economics, plastic pipe is being used with greater frequency as opposed to metallic pipe. Plastic pipe has the advantage that it does not rust as does metallic pipe. However, plastic pipe also has the disadvantage in that it is not as strong as metallic pipe and especially in the area of the fittings that interconnect the different sections of pipe, it is difficult to apply a sufficient amount of compressive force in connecting together of the couplers of the fitting in order to achieve a long lasting liquid tight connection.
In the past, in order to design a stronger plastic fitting or coupling, it has been common to incorporate one or more metallic members within the fitting that are to be used to establish a high degree of compression in forming of the fitting. Plastic fittings alone have been proved incapable of being torqued sufficiently to produce a leak proof fitting for a long period of time owing to its lesser strength compared to metals. Even after the incorporation of the metallic member, the fundamental problem of a liquid leak proof joint remained to be solved due to the formation of a gap at the surface of metal and plastic interface due to inherent property of plastic to shrink after injection molding. Sometimes this gap formation also occurs during over tightening of the fitting resulting in exterior leaks over a period of time. Inserting bigger sizes of metallic inserts and threading the entire length of metallic inserts, exteriorly or interiorly also adds to the cost which is finally to be borne by end users. Some of these prior art types of fittings require the use of several different parts which requires an assembly procedure of the fitting prior to interconnecting of the male coupler and female coupler of the fitting.
If the fitting is constructed totally of plastic, it has been discovered that a totally plastic male coupler and female coupler, when engaged, cannot be tightened sufficiently due to their inherent lesser compression strength than metal fittings to establish sufficient compression that will produce a long lasting liquid tight relationship between a pair of pipe sections.
SUMMARY OF THE INVENTION
The injection molding of a female coupler and a male coupler with each coupler being imbedded with a metallic insert. Each metallic insert includes a series of threads with these threads to be located at the position to be first engaged when interconnecting the male coupler and the female coupler. The first series of threads in any series of threads are the threads that are subjected to possible damage during engagement and also are subject to damage by an exterior object prior to engagement. Therefore, if these threads could be constructed of metal rather than plastic, the resulting pipe fitting is substantially improved because metal threads are stronger than plastic threads and therefore are damaged less. Each of the metallic inserts establish a boundary or interface with the plastic with this boundary communicating with a fluid conducting bore through the fitting. Inherently, this boundary is subjected to liquid being conducted along the boundary and eventually exiting at an exterior surface of the fitting. In order to minimize this possibility of leakage along this boundary, the metal insert is constructed to include at least one notch, protrusion and groove so as to provide a treacherous path for the leakage thereby minimizing the possibility of leakage. The notch, groove and protrusion also function to provide a tight interconnection between the plastic and the metal to keep the plastic bound tight against the metal. Inherently, after the injection molding process, there is a natural tendency for plastic to shrink and therefore produce a minute gap in the contact area between the plastic and the metal insert. The notch, protrusion and groove facilitate tight interconnection between the plastic surface and the metal surface to minimize the creation of any gap.
One of the primary objectives of the present invention is to create a pipe fitting which produces a leak-proof connection between the male coupler and the female coupler of the pipe fitting.
Another objective of the present invention is to construct a pipe fitting which is constructed mainly of plastic that utilizes imbedded metal inserts which are positioned at locations of high degree of wear so as to produce not only a long lasting leak-proof pipe fitting but also a pipe fitting to which a greater than normal degree of compression can be applied than if the pipe fitting were constructed solely of plastic.
Another objective of the present invention is to construct a pipe fitting which can be manufactured at a cost relatively less expensive than conventional metallic pipe fittings and thereby sold to the ultimate consumer at a relatively inexpensive cost.
REFERENCES:
patent: 3614137 (1971-10-01), Jacobson
patent: 4093280 (1978-06-01), Yoshizawa et al.
patent: 4179142 (1979-12-01), Schopp
patent: 4682797 (1987-07-01), Hildner
patent: 5215341 (1993-06-01), Namakura et al.
patent: 5350202 (1994-09-01), Fritz et al.
Munro Jack C.
Wilson Neill
LandOfFree
Pipe fitting does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pipe fitting, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pipe fitting will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2599682