GB2033037A - Joints for pipes or shafts - Google Patents

Abstract

Securing and sealing apparatus for fitment round a pipe 2 or 3 or, shaft or other body comprises a collar for fitment round the pipes, the collar having inflatable annular tubes 7 disposed in recesses 5 on its inner face so that in use the tubes 7 inflate radially inwardly of the collar against the pipes thereby securing the collar to the pipes, and thereby providing a joint and seal between them. <IMAGE>

Description

SPECIFICATION Securing apparatus This invention relates to securing apparatus, for example for securing to shafts or pipes.

Pipework is often constructed in restricted spaces, and as conventional methods of joining pipes together generally involve the use of a joint member having a gland which is tightened by screwing against the adjacent pipe ends these methods can be very difficult and awkward to perform.

An object of this invention is to provide securing apparatus which is simple and quick to use.

According to the present invention there is provided securing apparatus comprising an annular collar for fitment around a member to which it is to be secured, and a deformable chamber on an inner face of the collar, the chamber being inflatable so as to deform inwardly of the collar.

On inflation the chamber may expand in one, two or three dimensions, but the arrangement is such that it expands at least inwardly of the collar; this can be achieved by restricting its expansion in other directions by means of the shape of the collar or by providing the chamber with only a portion deformable.

The collar may have a recess in its inner face for location of the chamber, and the recess is preferably shaped so as to restrain the chamber from deforming in directions other than inwardly of the collar.

When the collar is fitted around, for example, an open end of a pipe and the chamber inflated the chamber deforms inwardly of the collar to contact the outer surface of the pipe and secure the collar in position. The collar may be closed at one end, and the chamber on inflation may form a seal against the pipe or other surface, so that the collar can provide a closure cap for a pipe, bottle or other openended object.

The chamber preferably has a valve through which the chamber is inflated and which prevents escape of fluid from the chamber.

The valve may be one-way if the apparatus is to be inflated only once for permanent fixing, or may be arranged to allow selective inflation and deflation of the chamber.

The chamber may be inflated with any suitable fluid whether liquid or gas; if the apparatus is to be inflated only once for permanent fixing the fluid may be for example a plastics material in its uncured liquid state which after inflation of the chamber cures to a solid, or a molten metal or other material which at normal temperatures is a solid; solidification of the fluid then ensures permanent inflation of the chamber.

When the apparatus is to be secured to a pair of end-to-end pipes or shafts the collar may include alignment means to ensure that the adjacent ends of the pipes or shafts intercommunicate at a desired angle; such alignment means may take the form of an abutment for the pipes to rest against in predetermined attitudes. If required, a plural ity of chambers can be provided spaced from one another along the collar.

The chamber can be made of any suitable material of which at least a portion is defor mable, for example, rubber, plastics material or thin metal; the material selected may depend on the environment and the substances with which it will come into contact. For many purposes, however, rubber will be most effective because of its ability to form a seal with material against which it is inflated. The chamber may have on its wall facing inwardly of the chamber a material, for example asbestos, which is not itself deformable by inflation but with which it is desired to contact the pipe.

It is advisable in some applications that the portion of the chamber which is to inflate against a pipe should be thicker-walled than the remainder.

The chamber wall facing inwardly of the collar may have a non-planar surface and this may increase its "grip" on the pipe or other surface which it is to contact; for example it may be ribbed or have a screw thread on it, and such screw thread may correspond with an external thread on a shaft, pipe or the like to which the collar is to be secured. This screw thread arrangement allows easy release of the collar from the shaft or pipe by unscrewing in the event of the inflated chamber being difficult to deflate after use. Other profiling of the pipe or shaft may be made to correspond with the form of the chamber and provide positive engagement of the chamber wall with the pipe or shaft.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a sectional side view of apparatus of this invention shown in use in joining two pipes together; Figure 2 is a section on the line A-A of Fig.

1; and Figure 3 is a sectional side view of a portion of an alternative form of the apparatus of the invention.

The apparatus of this embodiment is a clamp fitting having a rigid collar 1 into which adjacent pipe ends 2, 3 are inserted. The collar 1 is in the form of a tube having an internal diameter corresponding to the external diameter of the pipes 2, 3 to be joined, and has a central portion 4 extending into the tube bore by an amount corresponding to the thickness of the walls of the pipes 2, 3. The central portion 4 therefore provides an abutment limiting the extent of insertion of the pipes 2, 3 into the collar 1 and ensuring their correct alignment, but providing a passageway between the pipes 2, 3 of the same diameter as the pipes bore.

Two annular recesses 5 are formed in the inner face of the collar 1 each having a passageway 6 extending from it through the collar 1 to the outside. In each of the recesses 5 there is a chamber in the form of an annular rubber tube 7 whose inner wall 8 is thicker than the remainder, and each tube 7 communicates with the outside through an extension 9 in which a valve 10 is disposed.

In use, the pipe ends 2, 3 are inserted into the collar 1 one from each end as shown in Fig. 1 until they abut the central portion 4.

An air pump, which may be for example manually, electrically or mechanically driven, is then connected to each of the two extensions 9 in turn and air is pumped therethrough to inflate the annular rubber tubes 7.

As they inflate the tubes 7 expand, but this expansion is limited on three sides by the collar 1, so the tube 7 expands inwardly against the pipes 2, 3 walls. A pressure gauge can be used to ensure inflation of the tubes 7 to a predetermined pressure which is set depending on the material of the pipes 2, 3; thus, for example, for steel pipes the pressure could be much greater than for glass pipes.

On achievement of the appropriate pressure the pump is removed and the valve 10 prevents escape of air from the tube 7; the thick wall of the tubes 7 then presses against the walls of the pipes 2, 3, holding them in place.

Fluid can then be passed along the pipes 2, 3 and its flow will not be interrupted at the pipe joint because of the provision of the similar bore through the central portion 4. The clamp fitting therefore provides a simple and quick method of joining the pipe ends and avoids the use of spanners, etc, which require a considerable amount of space for operation.

The fitting can be removed simply by opening the valves 10 to release the air in the tubes 7 and then withdrawing the collar 1 from the pipes 2, 3; the fitting can then be re-used.

If the fitting is to be used at a bend in the pipework it can be designed to receive the pipes 2, 3 other than co-directionally by providing a bend in the bore of the collar 1.

Further, the bore of the collar 1 can have nonuniform diameter to allow pipes of different sizes to be interconnected.

In further embodiments the central portion 4 may be omitted, for example to allow the pipes 2, 3 to abut one another if desired. This can also be of use if the pipes are thin-walled so that minimal flow distortion will occur on passage from one pipe to the other, or to allow adjustment of the extent of insertion of the pipes into the collar to take up pipe length inaccuracies.

A compressed air cylinder or other source may be used instead of the air pump.

In Figs. 1 and 2 the collar 1 is shown as having a much greater outside diameter than the pipes 2, 3, but in modifications the collar can be made thin-walled and the shape of the tube 7 altered accordingly, so that the collar increases the diameter of the pipework only slightly at the pipe joints.

The fitting of Figs. 1 and 2 can also be used to seal holes in pipes by placing the collar 1 over the pipe in a position whereby the hole in the pipe is between the tubes 7.

Inflation of the tubes 7 provides a seal between the collar 1 and the pipe as well as locking it in position, and escape of fluid from the pipe is therefore prevented.

Referring now to Fig. 3, there is shown a shaft 11 which is screw threaded at one end portion 14, and a portion of a collar 1 similar to that of Figs. 1 and 2. In this case, however, the inflatable chamber is defined by part of the recess 5 and a part-toroidal seal 12.

The face 13 of the seal 12 directed inwardly of the collar is screw threaded to correspond with the thread of the shaft 11.

In use, the chamber is inflated as in Figs. 1 and 2, but as it inflates the threaded face 13 of the seal 12 engages tightly with the threaded end portion 14 of the shaft thus locking the shaft 11 and collar 1 together by providing positive engagement between them.

In the event of the collar 1 being in position for a long period of time, in which case the threads may become stuck together even after deflation of the chamber, the collar 1 can be removed from the shaft 11 simply by unscrewing.

The shape of the seal 12 is such that it can act as a valve for inflation of the chamber, as the flap 15 is resilient and is biassed to close off the passage through the extension 9. The greater the pressure within the chamber, the more tightly the flap 15 presses against the inlet passage.

The apparatus of the invention can be used in various forms for many purposes, for example for joining pipes and shafts, sealing pipes, providing quick-release couplings, and closing off pipe ends.

Modifications and improvements can be made without departing from the scope of the invention. For example the chamber can be provided in an end face of the collar to bear against a flap which on inflation of the chamber is pressed inwardly of the collar; in this case the chamber wall itself does not contact the pipe etc to be secured. Further, additional locks can be provided to hold the collar rigidly in place on the pipe or shaft if they are to be subjected to strong forces; such locks may be, for example, grub screws extending through the collar into the pipe wall, or corresponding screw threads on the collar body and the pipe so that the collar is screwed onto the pipe, and the chamber wall provides a seal against escape of fluid passing through the pipe. In a further embodiment the chambrer wall facing inwardly of the collar may be provided with an abrasive surface and the apparatus, when placed around a first shaft and rigidly connected to a second shaft, can form a clutch mechanism, so that if one of the shafts is moving relative to the other the chamber can be inflated to provide a rigid connection between them; deflation of the chamber releases the connection.

Claims (13)

1. Securing apparatus comprising an annular collar for fitment around a member to which it is to be secured, and a deformable chamber on an inner face of the collar, the chamber being inflatable so as to deform inwardly of the collar.

2. Apparatus according to claim 1, wherein the collar has a recess in its inner face, the chamber being located in the recess.

3. Apparatus according to claim 1 or 2, wherein the chamber is a toroidal deformable bag.

4. Apparatus according to claim 2, wherein the chamber wall is partly formed by the recess in the inner face of the collar.

5. Apparatus according to claim 1, 2 or 3, wherein a portion of the chamber wall facing inwardly of the collar is thicker-walled than the rest of the chamber.

6. Apparatus according to any one of the preceding claims, wherein a portion of the chamber wall facing inwardly of the collar has a non-planar surface.

7. Apparatus according to claim 6, wherein the non-planar surface has a screw thread formed on it.

8. Apparatus according to any one of the preceding claims, wherein a plurality of chambers are provided spaced from one another along the collar.

9. Apparatus according to claim 8, wherein the collar includes means for aligning a pair of members around which it is to be fitted.

10. Apparatus according to any one of the preceding claims, wherein the collar is closed at one end to provide a cap for sealing round an open-ended article.

11. Apparatus according to any one of the preceding claims, wherein a portion of the chamber wall facing inwardly of the collar has an abrasive surface.

12. Securing apparatus substantially as hereinbefore described with reference to and as shown in Figs. 1 and 2 of the accompanying drawings.

13. Securing apparatus substantially as hereinbefore described with reference to and as shown in Fig. 3 of the accompanying drawings.