IL150324A - Pipe coupling - Google Patents

Description

PIPE COUPLING mnrx nana The present invention relates to the axial interconnection of pipes which may be of different diameters.

More particularly, the invention provides a low cost pipe coupling which includes sealing means, gripping means and the option of interconnecting pipes of different diameters and different materials.

Small diameter pipes are easily interconnected by threading both pipe ends and inserting a sleeve coupling thereover. The threaded ends are susceptible to corrosion, and such a joint can be used only if it is possible to revolve at least one of the pipes. A sealant or a sealing material such as Teflon tape or flax fibers must be added to prevent leakage. Medium sized pipes - typically in the 3" to 8" range are usually joined by the use of flanges, whose sizes have long been standardized. Both types of connection are openable so that pipes can be replaced when necessary. There are also applications where the pipe ends are simply welded together without flanges, with the obvious consideration that there is no foreseen need to effect replacements. These connection means have been in use for more than a century.

Existing methods are less satisfactory with regard to large diameter steel pipes.

The forces operating to axially separate the pipe joint due to fluid pressure when in use are a function of the square of the pipe internal diameter. For example, if a 1 " pipe joint at a given pressure needs to resist 120N, a 10" pipe subjected to the same pressure requires its flanges to resist an axial force of 12000N. However the perimeter of the flange used for resisting such forces increases only in direct proportion to the pipe diameter. The result is that large pipe flanges are heavily loaded, and tend to leak. A common solution of welding bridging strips to join the flanges together makes replacement difficult and furthermore contributes nothing to maintaining the required pressure on any seal element used.

Many prior art pipe couplings are designed to squeeze together a pair of sloping side flanges assumed to be strongly attached or integral with the pipes. Examples of this type of coupling are seen in US Patents Nos. suc ange can not e coup e y suc ev ces.

While a full review of pipe couplings would need to be in book form, the state of the art can be assessed reasonably well from a review of the above, and additional, more recent US Patents.

Wilkins discloses a complex pipe coupling in US Patent No 6.007.106 which c ~~ ^ includes a plastic seal having high resistance to various chemicals. Frictional forces are relied upon to resist axial separation.

The present inventor has disclosed a moderate-cost coupling in US Patent No. which is capable of sealing pipes of two different diameters. However it has now been found that, in large diameter piping, the frictional forces generated by the compressed seal which prevent axial separation should be supplemented by other means.

Wolfsdorf in US Patent No.J3,312,025 do.es provide clamping elements to restrain axial separation of the two pipes. However the sealing arrangement makes no provision for accepting two pipes of different diameters.

In US Patent 6,361 ,082 B1 Hauki et al. discloses a pipe cuupiing intended for connecting plastic tubing of the type used for small diameter low pressure installations. The coupling includes an eccentric tightening arrangement. A pipe coupling seen in US Patent no. 6,378,915 B_1 Jo Katz is based on an outer housing, seal members and a nut-like member which is screwed to the outer housing to compress the seal members. No additional provision is made to prevent axial separation.

Provision to resist axial separation, and to effect sealing, are included in a coupling device seen in European Patent Application Hulsebos. The device is however quite complex and is not intended to accept pipes of two different diameters.

It is therefore one of the objects of the present invention . to obviate the disadvantages of prior art prior art pipe couplings and to provide a design which is suitable for large diameter pipes, can accept two pipes of different diameters and does provide resistance means against axial separation.

It is a further object of the present invention to achieve all of the above objects by a pipe coupling of moderate cost by use of a sheet metal construction.

The present invention achieves the above objects by providing a pipe coupling comprising a tube-like member with externally projecting flanges at each extremity, said flanges being provided with an inner face and an outer face, a pair of peripheral clamp members being arranged to contact said projecting flanges on said inner face thereof and provided with a recess delimited by an inward facing flange, said recess containing at least one resilient seal member, the improvement being that at least one resilient ring member in axial proximity to said seal member carries at least one metal gripping element mounted on the inner diameter of said at least one resilient ring member, and tightening of said peripheral clamp member causes said metal gripping elements to bite into the outer surface of a pipe to be held in said coupling.

In a preferred embodiment of the present invention there is provided a pipe coupling wherein pipes be interconnected, and wherein a plurality of concentric resilient ring members of different diameters are nested in each other, each of said ring members being provided with metal gripping elements mounted on the inner diameter of said ring member, the smaller diameter inner ring members being used to grip a pipe of a first diameter, said smaller ring members being selectively removable to allow gripping of a pipe of a second, larger outer diameter.

In a most preferred embodiment of the present invention there is provided a pipe coupling as wherein said concentric resilient ring members of different diameters are provided with inter-engagement grooves and projections to resist axial movement therebetween.

Yet further embodiments of the invention will be described hereinafter.

It will thus be realized that the novel device of the present invention serves to couple pipes of different diameters due to the peripheral clamp as well as options to add/remove seal elements. The structural parts of the coupling being made of sheet metal can be produced at low cost by press tools. There are no large diameter components requiring machining.

It will be seen in the drawings that the steel tooth elements which bite into the pipe to resist axial separation are arranged in an intermittent array, and staggered in some embodiments to avoid forming a peripheral ring in the pipe outer diameter which could later lead to pipe failure. Some embodiments of the steel tooth elements are also produced at low cost in press tool dies The invention will now be described further with reference to the accompanying drawings, which represent by example preferred embodiments of the invention. Structural details are shown only as far as necessary for a fundamental understanding thereof. The described examples, together with the drawings, will make apparent to those skilled in the art how further forms of the invention may be realized.

In the drawings: FIG. 1 is a sectional elevational view of a preferred embodiment of the coupling according to the invention, shown in its open state; FIG. 2 is a n end view of the same embodiment; FIG. 3 is a sectional elevational view of a further preferred embodiment of the coupling according to the invention, able to connect two pipes of different diameters; FIG. 4 is a detail view of the resilient rings seen in FIG. 3; FIG. 5 is a detail view of a sheet-metal element arranged to grip the pipe and to prevent outwards axial outward movement thereof; FIG. 6 is a plan view , at smaller magnification, of the toothed element seen in FIG. 5; FIG. 7 is a detail sectioned view of an embodiment provided with an interlocking toothed element; FIG. 8 is a sectioned enlarged view of said interlocking toothed element; FIG. 9 is a view of a toothed element which can be manufactured by forging or diecasting; FIG. 10 is a plan view , at smaller magnification, of the toothed element seen in FIG. 9; FIG. 1 1 is an end view of a further sheet-metal toothed element; and FIG. 12 is a plan view of the element seen in FIG. 1 1 .

There is seen in FIGS. 1 and 2 a pipe coupling 10, the central component of which is a tube-like member 12 with externally projecting integrally formed flanges 14 at each extremity. The flanges 14 are provided with an inner face 16 and an outer face 18. The member 12 can be fabricated from thin wall tubing or sheet metal.

A pair of peripheral clamp members 20 are arranged to contact the projecting flanges 14 on the inner face 16. Each clamp member 20 has a recess 22 which is fitted over the flange 14 of the tube-like member 12. The recess 22 is delimited by an inward facing flange 24, which contacts tn^^^r facej 6 and allows movement of the clamp member 20 when tightened or loosened.

The clamp members 20 are also configured in a manner suitable for manufacture from sheet metal.

At each side a support member 26 abuts the flange outer face 18, supporting the seal element 28 which is to contact the pipe (not seen) to be inserted. A resilient ring member 30 in axial proximity to the seal member carries at least one metal gripping element 32 mounted on the inner diameter of the ring member. The metal gripping element 32 need not be formed as a single strip, but can comprise a plurality of shorter strips.

By tightening the nut 34 and bolt 36, seen best in FIG 2,_ the clamp member 20 diameter is reduced. Thus the peripheral clamp member 20 causes the metal gripping elements 32 to bite into the outer surface of pipes to be held in the coupling, preventing axial separation thereof due to fluid pressure when the coupling 10 is in use and a fluid under pressure flows in the coupled pipes.

It will be noted that clamping is effected without any need to add a collar, flange or other projection to either pipe being coupled.

With reference to the rest of the figures, similar reference numerals have been used to identify similar parts.

FIG. 3 illustrates an embodiment of the pipe coupling 38 wherein pipes 40, 42 of substantially different outside diameter may be interconnected.

Seen near the outer edge 44 of the left side clamp member 46 are two concentric resilient ring members 48, 50 of different diameters, nested one inside each other. Each of the ring members 48, 50 are provided with metal gripping elements 52 mounted on the inner diameter of the ring member 48, 50. The smaller diameter inner ring member 48 is used to grip the pipe 40 of a first diameter, as seen on the left side of the figure. On the right side it is seen that one of the smaller ring members 48 has been removed to allow gripping of a pipe 42 of a second, larger outer diameter ring member 60a and gripping element 52a.

Preferably the gripping elements 52 are open, that is there is a gap 51 in the element 52 which varies in size to readily allow the incomplete ring to adapt to different diameter pipes.

The ring members 50, 50a are backed up by an outer further resilient component 53.

Referring now to FIG. 4, the resilient rings members 48, 50 already described with regard to FIG. 3 are seen to better effect..

The figure shows a preferred arrangement of the resilient ring members to retain the metal gripping element 52. Inwardly-projecting teeth 54 mounted on the inner diameter 56 of the ring members 48, 50. A second smaller diameter metal gripping element has external grooves to engage the first, larger diameter metal gripping element 52a.

The smaller diameter metal gripping element 52 is exposed and available to grip a pipe 40 of a first, smaller diameter.

The metal gripping element 52a is readily removable to allow the first metal gripping element 52 to contact a pipe 42 of a second, larger outer diameter. For ease of assembly and to prevent axial displacement when in use, additional inter-engagement groove and projections 58 features are provided both for the seal elements 28 and for the ring members 48, 50.

Referring now to FIGS. 5 and 6, there is depicted a detail of a metal gripping element 52 of the type seen in FIG. 4. The element 52 is a steel pressing having integrally-formed teeth 60 oriented to prevent outward axial movement of the pipe to be held in the coupling. The teeth 60 are substantially square in form, and are easily formed at low cost using a suitable press die. The sharp edges resulting, which in most sheet metal work are a nuisance and must be removed, are here utilized to constrain the axial motion of the pipes to be coupled.

Turning now to FIGS. 7 and 8, there is depicted a further embodiment of a gripping member 62. Teeth 64 are oriented to prevent outward axial movement of the pipe to be held in the coupling. Recesses 66 on the face 68 opposite to the teeth 64 interlock with projections of an outer ring. The outer ring can be a larger diameter gripping member 62a or a resilient back-up component 70.

FIGS. 9 and 10 illustrate another embodiment of a gripping member 72. The teeth 74 are staggered and oriented to prevent outward axial movement of the pipe to be held in the coupling, while avoiding unnecessary weakening of said pipe. This form of tooth can be produced by cold pressure rolling or forging.

In conclusion, FIGS. 1 1 and 12 illustrate a further sheet-metal embodiment of the gripping member 76, similar to 52 seen in FIG. 5, but having a rounded form 78 at the tooth root.

The scope of the described invention is intended to include all embodiments coming within the meaning of the following claims. The foregoing examples illustrate useful forms of the invention, but are not to be considered as limiting its scope, as those skilled in the art will readily be aware that additional variants and modifications of the invention can be formulated without departing from the meaning of the following claims.

Claims (6)

1. A pipe coupling comprising a tube-like member with externally projecting flanges at each extremity, said flanges being provided with an inner face and an outer face, a pair of peripheral clamp members being arranged to contact said projecting flanges on said inner face thereof and provided with a recess delimited by an inward facing flange, said recess containing at least one resilient seal member, the improvement being that at least one resilient ring member in axial proximity to said seal member carries at least one metal gripping element mounted on the inner diameter of said at least one resilient ring member, and tightening of said peripheral clamp member causes said metal gripping elements to bite into the outer surface of a pipe to be held in said coupling.

2. The pipe coupling as claimed in claim 1 , wherein pipes of substantially different outside diameter may be interconnected, and wherein a plurality of concentric resilient ring members of different diameters are nested in each other, each of said ring members being provided with metal gripping elements mounted on the inner diameter of said ring member, the smaller diameter inner ring members being used to grip a pipe of a first diameter, said smaller ring members being selectively removable to allow gripping of a pipe of a second, larger outer diameter.

3. The pipe coupling as claimed in claim 1 , wherein pipes of substantially different outside diameter may be interconnected, and wherein a resilient ring member retains at least one first metal gripping element provided with inwardly-projecting teeth mounted on the inner diameter of said ring member, a second smaller diameter metal gripping element having external grooves to engage said first, larger diameter metal gripping element, said smaller diameter metal gripping element being available to grip a pipe of a first

4. The pipe coupling as claimed in claim 2, wherein said concentric resilient ring members of different diameters are provided with inter-engagement grooves and projections to resist axial movement therebetween.

5. The pipe coupling as claimed in claim 1 , wherein said at least one metal gripping element is a steel pressing having integrally-formed teeth oriented to prevent outward axial movement of said pipe to be held in said coupling.

6. A pipe coupling substantially as described hereinbefore and with reference to the accompanying Advocates, Patent Attorneys & Notaries by: P-4946 -IL