This invention relates to a reinforcing ring for a plastic fitting and a plastic fitting incorporating such a reinforcing ring. The invention has particular utility with respect to fire sprinkler heads in buildings, although it will also have utility with other applications.
In the past, plastic fittings have been used for receiving a threaded male part, typically a threaded pipe. Also, in the past, reinforcing rings have been used to reinforce plastic fittings, such as described in U.S. Pat. Nos. 5,582,439 and 6,866,305 to Spears and U.S. Patent Application 2004/0051316 to Spears. Also, U.S. Pat. No. 4,682,797 to Hildner and U.S. Pat. No. 6,186,558 to Komolrochanaporn, as well as U.S. patent Application 2003/0184085 to Thompson, disclose a reinforcing ring used with plastic fittings.
Although reinforcing rings that have been made in the past, and used with plastic fittings, there have been problems with such rings and fittings, particularly relating to cross-threading and shearing. Therefore, the present invention provides an improved reinforcing ring and an improved fitting incorporating the reinforcing ring.
One problem is that when the male part which is being inserted into the plastic fitting is over-tightened, there is a tendency for the plastic fitting to shear.
Also, cross-threading occurs when the thread axis of the male part is not properly aligned relative to the female fitting's thread axis. All plastic thread design is susceptible to cross-threading. One way of at least reducing the risk of cross-threading is to guide the male part to be axially in line with the female fitting. Another way to lessen the likelihood of cross-threading is to reinforce the first few plastic threads of the fitting with a harder material. The present invention has been able to successfully combine both of these approaches to provide an improved method of reducing the likelihood of cross-threading using only a single starter thread. None of the prior art reinforcing rings use only a single starter thread.
Accordingly, it is an object of this invention to at least partially overcome the disadvantages of the prior art. Also, it is an object of this invention to provide an improved reinforcing ring for plastic fittings and an improved plastic fitting incorporating the reinforcing ring.
Accordingly, in one of its aspects, this invention resides in providing a reinforcing ring for a plastic fitting, comprising: a first tubular portion; a radial portion extending radially inwardly from a forward end of the tubular portion; a guide portion extending rearwardly from a radially-inner region of the radial portion; and a starter thread extending radially inwardly from a rearward end of the guide portion.
In a further aspect, the present invention resides in providing a plastic fitting for receiving a threaded male part, comprising: a plastic body having inner plastic threads for receiving the male part in threaded engagement; and a reinforcing ring as described above wherein the first tubular portion of the reinforcing ring surrounds at least a portion of the plastic body.
Further aspects of the invention will become apparent upon reading the following detailed description and drawings which illustrate the invention and preferred embodiments of the invention.
In the drawings, which illustrate embodiments of the invention:
As shown in
In one preferred embodiment, the guide portion 20 is tubular. In another preferred embodiment, the guide portion 20 is conical and extends rearwardly and inwardly as seen in
Preferably, the tubular portion 14 is conical, preferably at about 86° from horizontal, but the tubular portion 14 may be cylindrical (90° from horizontal).
Preferably, the reinforcing ring 10 is stamped from a metal sheet 42 and in a more preferred embodiment the ring is made of stainless steel. The reinforcing ring 10 can also be made of technical plastic materials and/or ceramics.
Preferably, the reinforcing ring 10 may be stamped from the steel sheet 42, preferably a stainless steel sheet.
When the reinforcing ring 10 is stamped in this manner, the starter thread 24 is no more than 360° around the guide portion 20. In a preferred embodiment, the starter thread 24 is 360° around the guide portion 20. In another preferred embodiment, the starter thread is less than 360° around the guide portion as seen in
As will be seen from the Figures, the reinforcing ring 10, particularly when stamped from a metal sheet 42, is dimensioned such that the thickness T of each of the first tubular portion 14, the radial portion 16 and the guide portion 20 (as best seen in
The plastic fitting 12 is intended to and does receive a threaded male part 28 as seen in
Preferably the guide portion 20 of the reinforcing ring 10 forms a guide portion 36 of the fitting 12 for guiding the male part 28 to the starter thread 24. This reduces the likelihood of cross-threading.
Preferably, the starter thread 24 of the reinforcing ring forms a lead face 40 of the first thread 32A of the threads 32 of the plastic body 30.
Preferably, when the reinforcing ring 10 is properly installed as part of plastic fitting 12, the radial portion 16 of the reinforcing ring 10 forms a forward protective portion 38 protecting the plastic body 30 from contact with the male part 28 as the male part 28 initially engages the fitting 12.
Preferably, the first tubular portion 14 of the reinforcing ring 10 surrounds at least a portion 34 of the plastic body 30.
Preferably, the plastic fitting 12 is molded with the first tubular portion 14 of the reinforcing ring 10 within and surrounded by a portion 44 the plastic body 30.
Typically there are several inner threads 32 of the plastic body 30. There will be at least a first inner thread 32A (as best seen in
More preferably, the first tubular portion 14 extends rearwardly beyond the last thread 32B of the plastic body 30.
It will be understood that, although various features of the invention have been described with respect to one or another of the embodiments of the invention, the various features and embodiments of the invention may be combined or used in conjunction with other features and embodiments of the invention as described and illustrated herein.
Although this disclosure has described and illustrated certain preferred embodiments of the invention, it is to be understood that the invention is not restricted to these particular embodiments. Rather, the invention includes all embodiments which are functional or mechanical equivalents of the specific embodiments and features that have been described and illustrated herein.
Number | Date | Country | Kind |
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2524768 | Oct 2005 | CA | national |
This application is a continuation in part of U.S. patent application Ser. No. 11/356,954 filed Feb. 21, 2006 and entitled “Reinforcing Ring for a Plastic Fitting and Plastic Fitting Incorporating a Reinforcing Ring” which has now issued to U.S. Pat. No. 7,597,363.
Number | Name | Date | Kind |
---|---|---|---|
299063 | Story | Jun 1880 | A |
2702565 | Mortiz | Feb 1955 | A |
2352574 | Arthur | Nov 1967 | A |
3899004 | Marelli | Aug 1975 | A |
4093280 | Yoshizawa | Jun 1978 | A |
4179142 | Schopp | Dec 1979 | A |
4335753 | Freye | Jun 1982 | A |
4655256 | Lasota | Apr 1987 | A |
4682797 | Hildner | Jul 1987 | A |
4756857 | Dezio | Jul 1988 | A |
5109929 | Spears | May 1992 | A |
5366257 | McPherson | Nov 1994 | A |
5437481 | Spears | Aug 1995 | A |
5454675 | DeHaitre | Oct 1995 | A |
5582435 | Goto et al. | Dec 1996 | A |
5582439 | Spears | Dec 1996 | A |
6186558 | Komolrochanaporn | Feb 2001 | B1 |
6866305 | Spears | Mar 2005 | B2 |
6991268 | Spears | Jan 2006 | B2 |
20030184085 | Thompson | Oct 2003 | A1 |
20040051316 | Spears | Mar 2004 | A1 |
Number | Date | Country |
---|---|---|
02 299929 | Dec 1990 | JP |
Number | Date | Country | |
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20100038905 A1 | Feb 2010 | US |
Number | Date | Country | |
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Parent | 11356954 | Feb 2006 | US |
Child | 12461940 | US |