Pipe joints or couplings – Movable jaw – Wedge bushing
Reexamination Certificate
1997-01-28
2001-07-10
Luu, Teri Pham (Department: 3627)
Pipe joints or couplings
Movable jaw
Wedge bushing
C285S322000, C285S096000
Reexamination Certificate
active
06257628
ABSTRACT:
The present invention relates to a coupling device a tube comprising a sleeve part having at least one insert end for the tube and a sealing organ suitable to provide a seal around the tube inserted into the sleeve part.
Such a coupling device is known from the European patent No. 0 418 961. In this known coupling device a sealing organ is used consisting of an inner ring enclosed by a rubber sealing jacket, which inner ring is supported by supporting surfaces of the sleeve part so as to push this sealing ring against the outer wall of the tube. This known coupling device is capable of accepting and coupling tubes having different diameters so that a seal is provided for liquid, gas and solids, and tubes of different diameters and, if required, different materials can be coupled to each other.
This can be achieved with the known sealing ring because it can be compressed in circumferential direction and to a certain extent around the tube so that it is possible to adapt to the different tube diameters, while in cross-section the sealing ring retains its form relatively well.
This known device still exhibits a number of problems. First, when using the known coupling device with smaller tube diameters, the support of the sealing ring may pose a problem due to the sealing ring having to be deformed to such an extent that the sealing effect is no longer guaranteed. Another problem with the known coupling device is that it does not have sufficient tensile strength. These coupling devices are usually applied to couple underground tubes, for instance under a road. Through movement of the ground, possibly caused by traffic, such a coupling is not imbedded securely and due to displacement of sand and the like the coupling of the known coupling devices may loosen so that leakage occurs.
The invention now aims to offer a solution to these problems. To this effect the coupling device of the invention is characterized in that the sealing organ comprises a plurality of slidably abutting elements forming part of a substantially closed ring, and which elements radially increase in thickness, and which organ is further provided with pressure means for pressing the elements against the tube inserted into the coupling device.
The coupling device according to the invention provides seals which can be used both inside and outside of the tube. The pressure means serve to press the elements against the tube from the outside inward respectively from the inside outward to conform to the tube.
In this way the ring formed by the elements can, with respect to diameter, easily adapt to the tube to be sealed, while also easily accommodating irregularities in the surface of the tube. The elements could be arched but it is preferable that the elements are substantially wedge-shaped. The lateral faces forming the wedge of the wedge-shaped elements may, for instance, form an angle of 60°, in which case 60 wedge-shaped elements suffice to form the closed ring. The sealing ring may, for a part, also consist of differently shaped elements, but also other numbers of such elements are possible. For instance, if the angle between the wedge-forming lateral faces is 5°, 72 elements are required to form the closed ring. The more elements are used, the finer the distribution and closer the fit against the tube to be sealed.
The invention is based on the surprising realization that by shifting the abutting elements the elements rotate so that diameter adjustment takes place by means of the elements forming the closed ring. When applied to the outside of the tube, the desired diameter is adjusted by starting with a larger diameter and then pressing the elements by means of the pressure means against the tube, whereby adjustment to the desired diameter of the closed ring occurs automatically.
In order to obtain the required firmness of the seal it is desirable that each element is provided with a notch on a first side and a projection on a second side opposite the first side of the element, which notch and projection are suitable to interact with a corresponding projection respectively notch of an abutting element. This locks the sealing organ to prevent mutual wrenching of the elements.
The sealing effect of the coupling device according to the invention is aided by the fact that the sealing organ comprises a rubber ring, a portion at least of which is placed between the tube and the elements. It is conceivable to have the rubber ring completely surrounding the assembly of elements, but this is not necessary to achieve the aim of the invention.
In an alternative embodiment the side of the elements abutting against the tube are partly made of rubber. The tension-relieving effect of the coupling device according to the invention is achieved in particular if at least some of the elements are for a part provided with a rough surface abutting against the tube. For this there are also different options possible. For instance, one or more elements may be provided with a toothed grip element. This relieves the tension very effectively. It is, however, also possible to provide the rough surface by glueing sand grains on to the particular surface of the elements. In another embodiment the elements are provided with a grip ring extending at least over part of the circumference of the tube.
To support the tension-relieving effect at least some of the elements that are distributed evenly over the circumference of the tube may be made of a material harder than that of the tube, such as metal, and preferably stainless steel.
To optimize the close fit of the elements abutting against the tube in circumferential direction, independently of the tube's diameter discrepancies, the elements' surface abutting against the tube is arched in the circumferential direction of the tube.
Various systems could serve as pressure means for the wedge-shaped elements.
In a first embodiment of the coupling means according to the invention the pressure means for the elements are provided with a hydraulic ring-shaped chamber containing the elements which serve this chamber as a displaceable wall; the hydraulic chamber is also provided with a sealable connecting opening for the supply of a fluid to produce the hydraulic pressure in the chamber.
However, in an alternative embodiment the coupling device is executed such that the sleeve part, at least around the tube, is provided with a support surface for the elements, the diameter of which support surface in longitudinal direction of the tube decreases, respectively increases, whereby the support surface, by interaction with the elements, forms the pressure means for pressing the elements against the tube.
The invention is also embodied in a separate sealing organ and a separate wedge-shaped element such as can be applied in the coupling device according to the invention.
REFERENCES:
patent: 2201372 (1940-05-01), Miller
patent: 2230725 (1941-02-01), Nathan
patent: 3288497 (1966-11-01), Nydam
patent: 3486772 (1969-12-01), Elsner
patent: 3860270 (1975-01-01), Arnold
patent: 4119335 (1978-10-01), Rieffle et al.
patent: 4676531 (1987-06-01), Martin
patent: 5037144 (1991-08-01), Peting et al.
patent: 5188401 (1993-02-01), Stainforth
patent: 5350204 (1994-09-01), Henniger
patent: 5476292 (1995-12-01), Harper
patent: 2731464 (1978-03-01), None
patent: 4219722 (1993-12-01), None
patent: 0 418 961 (1991-03-01), None
patent: 2072296 (1971-09-01), None
patent: 63780 (1934-04-01), None
patent: 4002770 (1994-02-01), None
Darby & Darby
Georg Rischer Waga N.V.
Luu Teri Pham
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