GB2200180A - Pipe coupling - Google Patents

Abstract

The invention refers to a sleeve coupling for connecting pipes together. The sleeve has a central cylindrical body (2) and ring nuts (5, 6) suitable for screwing to the ends of same. The sleeve also has locking rings (9, 10) with a wedge-shaped radial cross-section capable of locking the ends of the pipes to be connected together by interaction with the ring-nuts. Elongated rings (18, 19) are also provided, inserted between an annular rib (17) in the central cylindrical body (2) and said locking rings (9, 10). According to the invention, each locking ring (9, 10) is made integral with its corresponding elongated ring (18, 19) by a spirally-shaped axially-yielding elastic element (100). <IMAGE>

Description

TITLE Pipe Coupling The subject-matter of this invention consists of a perfected sleeve coupling for connecting together metal pipes or pipes made of synthetic material.

The sleeve coupling according to the invention is preferably made of high-density synthetic material, although it can be made of other materials.

Sleeve couplings consisting substantially of a cylindrical body, the ends of which are threaded externally to accommodate two ring nuts, are known.

These ring nuts have truncated-cone shaped internal ends able to force against the outer edges of the pipes inserted into the body of the coupling a locking ring having a wedge-shaped radial cross-section whose inside surface is fitted with teeth, ribs or some other projection able to provide a grip on the outer surface of the pipe.

In this way, by screwing the ring nuts onto the cylindrical body of the joint, mechanical gripping of the pipes inserted into the body is caused.

This locking ring with a wedge-shaped radial crosssection is suitably equipped with a radial cut so that its diameter may be decreased by exerting pressure from outside.

In these couplings of a known type, hydraulic sealing is entrusted to a toric gasket, such as an 0ring, housed in a circular groove prepared in the inner surface of the cylindrical body of the coupling.

The purpose of this toric gasket is to get a grip on the outer surface of the end of the pipe inserted into the sleeve coupling.

#ccording to a previous invention by the same owner (Italian patent no. 1.005.415), instead of said annular groove, on each end of the body of the coupling there is a bore defining a conical shoulder against which one side of said gasket rests.

On the other side, said toric gasket is pressed by the end of an elongated ring which surrounds the pipe and which rests against the locking ring.

In this way, when the ring nut is screwed against the body of the sleeve, the inner conical surface of the ring nut pushes the locking ring axially and radially against the surface of the pipe.

The axial component of the movement of the locking ring is transmitted to the elongated ring, which in turn compresses the annular gasket.

This arrangement is particularly efficient, but requires that for two symmetrically opposing pipes the sleeve coupling be made up of, in this order - the body of the sleeve - the two threaded ring nuts - the two toric gaskets - the two locking rings - the two elongated rings which have to transform the axial movement of the locking rings into compression of the toric gaskets.

The purpose of this invention is that of reducing the number of elements required to make up a coupling, by elimina#ing the two elongated rings.

The simplest way to solve this problem would seem to be that of making the locking rings and the elongated rings integral with one another : the number of pieces to be stocked and the number of operations for assembly of the coupling would thus be reduced by two. It is however not possible to apply this solution just like that.

It must be remembered that the locking ring is crossed through radially by a cut which allows it to be reduced in diameter, with the consequent radial locking of the underlying pipe through the action of the pressure developed by the threaded ring nuts.

The discontinuous circumference formed by the cut in question may not be extended to that part of the ring which has to compress the annular gasket : a difference in pressure along the circumference of the gasket would inevitably lead to a loss of the gasket itself.

According to this invention, the problem has been overcome by making the elongated ring continuous in a circular direction on the one hand, and the locking ring with a radial cut on the other, and by joining these two parts by a third extremely yielding element, preferably consisting of a double helical spring.

The essential characteristics of the invention are summarized and schematically described in the claims; its aims and advantages are also indicated in the following description with particular reference to the attached drawings, in which - figure 1 shows, half as a cross-section and half as a view, a sleeve according to the invention; - figure 2 is a side view of the ring made up according to the invention, formed by a locking ring and an elongated ring joined to one another by a elastically yielding double helical spring; - figure 3 is a front view of the complete ring along the line 111-111 of figure 2; - figure 4 is a side view on the plane IV-IV of figure 3 - figure 5 is a section of the complete ring along the plane V-V of figure 2.

With particular reference to the figures listed above, the sleeve coupling, indicated as a whole by the number 1, comprises, in a known manner - a cylindrical body 2, the outer ends of which (3 and 4) are threaded; - two internally threaded ring nuts (5 and 6) having a truncated-cone surface (7 and 8).

The outer truncated-cone surfaces of the gripping rings (9 and 10) whose radial cross-section is wedge-shaped slide over the truncated-cone surfaces of the ring nuts (7 and 8).

The gripping rings (9 and 10) are cut through in a radial direction so that they can contract when they are submitted to the external radial pressure exerted by the ring nuts 5 and 6 when these are screwed onto the threaded ends (3 and 4) of the cylindrical body (2).

In sleeves of the know type, screwing of the ring nuts CS and 6) causes both the contraction of the locking rings (9 and 10) and their axial movement.

The axial movement of the locking rings (9 and 10) , after recovery of an initial clearance, is transmitted to the elongated rings (18 and 19) which, in known solutions are separate from the locking rings (9 and 10) , and as compared to the latter also form a con tinuous circle, that is to say they have no radial gap in them.

Under the axial thrust of the locking rings (9 and 10), the elongated rings (18 and 19) in turn compress the 0rings 20 against the annular shoulder (17) of the cylindrical body (2) axially, and, radially outwards against the inside surface of said sleeve 2 and inwards against the outer surfaces of the pipes ( and 2).

Sealing of the joint is thus achieved.

ccordin.3 to this invention, as described above, the locking rings 9 and 10 are not separate and disjointed from the elongated rings 18 and 19, but are joined to these by means of double helical springs 100, clearly visible in figures 2 to 5.

In a resting position, as illustrated in figures 2, 4 and 5, and on the right side of figure 1, the turns 100 which join the locking rings to the elongated rings are separated by a clearance which allows screwing of the ring nuts 5 and 6 over the threads of the cylindrical body 2.

Once the clearance between the turns 100 has been recovered, the locking ring 9 or 10 respectively applies to the elongated rings 18 or 19, through the turns 100 by now touching one another, the axial thrust needed to compress the annular gaskets 20.

In this way we have a compound element (9, 10 - 18, 19 - 100) which performs the tasks of the pairs of elements 9 - 18 and 10 - 19 respectively, with no reductions in the degree of liberty required of the two pairs of elements during the delicate gripping phase of the joint, and a considerable simplification of the assembly operations and a reduction in stocks.

It should be noted that the root of the turns 100 ends suitably in a circular widening 101, and this allows an increase in the elasticity of the connecting element 100.

It should also be noted that although the figures refer to the case of a symmetrical sleeve, to be used for connecting together two pipes having the same diameter, this invention may also be applied to sleeves used for joining pipes to different diameters.

Furthermore, the sleeve may be equipped with a dissymmetrical tubular central body 2, which on one end has a threaded trunk 3, a ring nut 5, a pipe ii, a locking ring 9 and an elongated ring 18 joined to the locking ring by the turns 100, while at the other end it may be connected to a circuit of pipes in any suitable manner (for example by threading, gluing, welding or other similar ways).

The coupling of this invention may be sold wholly or partly unassembled, as a kit of parts, and in some circumstances, the parts may be grouped together with identical parts and sold separately, e.g. for commercial building operations.

The present invention has been described above purely by way of example, and modifications can be made within the spirit of the invention.

Claims (13)

Claims

1. A pipe coupling, comprising: a component having at least one bore for receiving a pipe, the bore defining an annular shoulder spaced from its end, and the component having screw-threading for screwing a ring nut onto the component; a sealing ring for insertion into the bore, around the pipe. for resting against the shoulder: a ring nut for screwing onto the screw-threading of the component; and a gripping ring which will go round the pipe and coact with the ring nut to contract onto the pipe as the ring nut is tightened on the component and hence grip the pipe firmly in the component, the gripping ring including an annular abutment element which is connected to the gripping ring by an axially-yielding element, the abutment element being for engaging the sealing ring to compress it against the shoulder and hence seal the pipe to the component.

2. The pipe coupling of Claim 1, wherein the axially-yielding element yields elastically.

3. The pipe coupling of Claim 2, wherein the axially-yielding element comprises at least one member of helical shape.

4. The pipe coupling of Claim 3, wherein there is a rounded widening at at least one end of the helical-shape member.

5. The pipe coupling of Claim 3 or 4, wherein there are at least two of the helical-shape members, parallel to one another.

6. The pipe coupling of any of the preceding Claims, wherein the component is in the form of a cylindrical body for coupling two pipe ends.

7. The pipe coupling of any of the preceding Claims, wherein the screw-threading is external threading, the ring nut has a conical inner surface, the gripping ring is of wedge shape in radial cross-s#ction, to coact with the conical inner surface of the ring nut, is interrupted so as to contract onto the pipe on tightening the ring nut, and has internal teeth for engaging the exterior of the pipe, and the sealing ring is of the O-ring type.

8. The pipe coupling of any of the preceding Claims, with any of the sealing ring, ring nut or gripping ring assembled with the component.

9. The pipe coupling of any of Claims 1 to 7, with the component secured to and sealed to a pipe by means of the gripping ring, ring nut and sealing ring.

10. A ring nut for the pipe coupling of any of Claims 1, 6 or 7, the ring nut having screw-threading for screwing onto the screw-threading of said component, and including an annular abutment element which is connected to a ring nut by an axially-yielding element, the abutment element being for engaging said sealing ring to compress it against said shoulder and hence seal said pipe to said component.

11. The ring nut of Claim 10, and as specified in any of Claims 2 to 5.

12. A pipe coupling, substantially as herein described with reference to, and as shown in, the accompanying drawings.

13. A ring nut including an annular abutment element, substantially as herein described with reference to, and as shown in, the accompanying drawings.