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Publication numberUS784931 A
Publication typeGrant
Publication dateMar 14, 1905
Filing dateSep 27, 1904
Priority dateSep 27, 1904
Publication numberUS 784931 A, US 784931A, US-A-784931, US784931 A, US784931A
InventorsJames R Duncan
Original AssigneeJames R Duncan
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Closure for plumbing-traps or the like.
US 784931 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)



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UNITED STATES Patented March 14, 1905.



SPECIFICATION forming part of Letters Patent No. 784,931, dated March 14;, 1905.

Application filed September 27, 1904. Serial No. 226,115.

To all whom it may concern:

Be it known that I, J AMES R. DUNCAN, a citizen of the United States, residing at New York, in the county and State of New York, have invented certain new and useful Improvements in Closures for Plumbing-Traps or the Like, of which the following is a specification, reference being had to the drawings accompanying and forming part of the same.

In modern sanitary plumbing systems it is desirable and in many cases necessary that traps, bends, and the like be so constructed as to offer ready access to their interior for the purpose ofinspection, cleaning, &c. Such devices are therefore provided with suitable apertures and removable closures. The latter must fit tightly, so as to withstand the internal pressure of the system, and at the same time should be easily removed when desired. \Vhere the closure and the surface on which it seats are both made of iron, it is found that the two frequently rust together to such an extent as to make the removal of the cap impossible or extremely difiioult. It has therefore been proposed to make the closure or cap of brass, which of course does not corrode as iron does, or to make the closure of brass or iron and provide in the aperture a thimble of brass to receive the closure. The latter method is effective for rendering the cap readily removable, but possesses certain disadvantages in construction. For example, before a plumbing system is pronounced ready for use it is subjected to highinternal pressure to test its tightness and strength. For this purpose the trap-holes, 620., must be closed. Inasmuch as the brass thimble to be used as the closure seat cannot withstand tight calking between it and the surrounding iron walls of the opening in which it fits it is customary for testing purposes to calk an iron plug very firmly in the opening. After the test is made the plug is removed and the calking, usually lead, is out out. This makes the testing a very troublesome procedure and one that necessitates considerable labor after its completion to put the system in final shape by removing the plugs and calking, then fitting and lightly calking in the brass thimbles or rings which are to receive the removable closure.

1 have therefore been led to devise my present invention, which has for its object to provide a closure for such apertures which may be seated and held with sufiicient firmness to withstand the necessary tests and yet be removable with the greatest readiness. For this purpose I. locate in the inside of the aperture a flaring or tapered ring of brass constituting a seat for the closure, also preferably of brass,which is of corresponding shape. The latter is forced into the seat, thereby forming a perfectly tight joint, by a cap, preferably of brass, which screws over the outside of the walls of the aperture. The screwthreads of the cap and hub or collar on which it is secured are thus completely protected from the moisture in the pipe. As will be readily understood, such a construction furnishes a perfectly tight joint which will withstand any pressure to which it may be subjected, but which can be readily opened for cleaning or inspecting the interior of the pipe by removing the outer cap and lifting out the brass plug.

The invention itself consists in the novel features and combinations of elements hereinafter described, and more particularly set forth in the claim.

A convenient embodiment of the same is shown in the accompanying drawings, in which* Figure 1 is a longitudinal section of a trap to which my invention is applied. Fig. 2 is a perspective view of the closure or plug used in the construction shown in Fig. 1.

The trap illustrated is of the double handhole type, having a pair of nipples or collars l 2, constituting the hand-holes. The inside of each is screw-threaded, as at 3, and provided with a shoulder, as L, upon which rests the eXteriorly-tlireaded ring or seat 5. The latter is preferably made of brass and tapers downwardly on the inside, as shown. Closely conforming to the taper of the ring 5'is a closure or plug 6, also preferably made of brass. This member is shown in perspective in Fig. 2. It is provided with a nut or stud 7, which may be engaged by a wrench in order to start the closure from its seat, and has also a bail or other device 8 for easily lifting the closure from its place. The plug 6 would be of such size relative to the seat 5 that it will not rest therein flush with the top of the ring and collar, but will project above the same a slight distancesay a sixteenth, eighth, or quarter of an inch.

Over the closure or plug 6 is a cap 10, having interior threads to engage those on the outside of the collar or hub, as shown. The innner side of the top'of the cap has a cavity 11 to receive the stud 7 of the plug 6, so that the cap will bear on the plug around the pe riphery ot' the latter instead of on its wrenchstud. This plan puts the strain on the parts best adapted to withstand the same namely, on parts removed from the centers of the cap and closure thus obviating any tendency to buckle. To provide space for the depression or cap 11, the top of the cap need not be thickened, but may be provided with a boss 12. The latter may be squared or otherwise shaped for ready engagement by a wrench for removing the cap, or the wrench may be applied to the body of the cap in the usual way. As for the material of which the cap is made, I prefer brass, as this metal does not rust, and the cap may therefore be left in place for a long period and still be at all times readily removable.

I have shown my closure applied only to the hand-holes of a trap; but it will be obvious that it may be used wherever an easilyremovable closure is desired, such as in sewerfittings, rain-leaders, and plumbing-fittings of all kinds. Whether the section of pipe in which it is used is connected to the adjoining sections by calking, as would be the ease with the trap illustrated in the drawings, or by screw-threads is of course immaterial.

WVhat I claim is The combination of a fitting having a handhole or similar opening formed in a neck integral with the body of the fitting, said opening having an inner shoulder, a tapered seat of non-corrodible metal screw-threaded in the opening and seated on the shoulder, a correspondingly-tapered closure of similar metal fitting the seat and having a stud or boss to be engaged in removing the closure, and a cap of non-eorrodible metal screwed upon the neck over the closure and having an imperforate top with a cavity in its inner surface to receive the boss on the closure, whereby the closure is engaged around its periphery only, and forced firmly into its seat by the pressure of the cap, substantially as shown and described.

JAMES R. DUNCAN. Witnesses:


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2553340 *Oct 22, 1947May 15, 1951Theodore C SmithSeal for auxiliary filling nipples
US2567455 *Aug 9, 1949Sep 11, 1951Edward F HyattCombination pepper-and-salt shaker with two-piece bottom closure
US5899234 *Mar 13, 1997May 4, 1999Plastic Prodution A LlcTest closure plug for the trap bushing of a conventional T-fitting
US8657145 *Apr 30, 2009Feb 25, 2014Vector International LimitedCap for a port of a pressurized container or conduit
US20030116966 *Oct 4, 2002Jun 26, 2003Gray Franklin E.Bullthread
US20060181082 *Apr 10, 2006Aug 17, 2006Gray Franklin EBullthread
US20100276425 *Apr 30, 2009Nov 4, 2010Vector International LimitedCap For A Port Of A Pressurized Container Or Conduit
Cooperative ClassificationB65D47/122, Y10S285/901