Connector for connecting to a tube

A connector having a body 1 with a central throughway in which a tube T is received. A collet 30 within the body has a plurality of flexible legs 32 arranged to grip the tube T if a force is applied to withdraw the tube. The connector further comprises at least one first tooth 14, the first tooth having a gripping edge in a plane angled to a plane perpendicular to the main axis of the connector, and being mountable with respect to the body so as to be non-rotatable about the main axis X.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to United Kingdom Application No. 1317952.8, filed Oct. 10, 2013, the contents of which is incorporated herein by specific reference.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention relates to a connector for connecting to a tube.

2. The Relevant Technology

In particular, the invention is directed to an improvement in a connector for connecting to a tube, the connector having a body with a central throughway in which the tube is received, in use, and defining a main axis at its centre; a collet retained within the body, the collet comprising a plurality of flexible legs, the legs being arranged to bear against a cam surface in the body such that a force on the collect tending to pull it out of the body causes the legs to interact with the cam surface and be deflected inwardly to grip the tube, in use. Such a connector will subsequently be referred to as “of the kind described”.

Collets of the kind described have been made by the applicant for decades. The collets are designed to grip the tube and stop it from moving in an axial direction. However, they do not stop the tube from rotating as the collet itself can typically rotate within the connector. In some cases, such as that disclosed in EP 2 400 201, the collet is prevented from rotating within its housing. In this case, the teeth on the collet simply cut a circumferential groove in the tube allowing it to rotate freely. In many cases, this ability for the tube to rotate is not a problem and may indeed be an advantage as it keeps torsional stresses on the tube to a minimum.

However, in some circumstances, it would be advantageous for the tube not to be able to rotate within the connector. For example, in a shut-off valve, particularly one with a long actuator handle, the valve would be easier and more convenient to use if the valve's radial orientation was fixed. This would also result in a neater installation.

The present invention is aimed at providing a connector of the kind described in which the tube cannot readily rotate within the connector.

SUMMARY OF THE INVENTION

According to the present invention, a connector of the kind described is characterised by further comprising at least one first tooth, the first tooth having a gripping edge in a plane angled to a plane perpendicular to the axis, and being mounted with respect to the body so as to be non-rotatable about the main axis.

A tooth which is angled in this way is much more readily able to resist rotation of the tube than a conventional collet tooth. Because it is angled, the tooth presents a broader face than the “knife edge” represented by a typical collet tooth.

Even a small angle between the gripping edge and the plane perpendicular to the axis will cause some degree of resistance to rotation. However, preferably, the angle is between 20° and 70° and more preferably between 30° and 60° with respect to the plane perpendicular to the axis.

The or each first tooth may be in the collet and the collet is non-rotatable about the main axis with respect to the body. Alternatively, the or each first tooth may be in a component different from the collet which is non-rotatable about the main axis with respect to the body.

The tooth may be positioned in a non-tapering portion of the throughway. However, this will provide relatively little gripping force, or may unduly interfere with the tube upon insertion. Preferably, therefore, the housing has a tapered surface which tapers in the axial direction positioned to urge the or each first tooth radially inwardly as it is moved axially into the body. This initially allows greater room for insertion of the tube, but causes the or each first tooth to be urged radially inwardly thereby increasing the gripping force and hence the resistance to rotation of the tube.

It is possible for the tube itself to urge the or each first tooth onto the tapered surface upon insertion. However, preferably, the connector further comprises a locking ring which is arranged to be advanced along the body after insertion of the tube and, in doing so, to cause the tapered surface to urge the first teeth radially inwardly. Thus, the tube will be inserted into the correct position without interference from the or each first tooth, whereupon the locking ring can be moved into place thereby causing the or each first tooth to grip the tube.

The body may also be provided with a radially tapered surface positioned to urge the first teeth radially inwardly as they are urged about the axis. The nature of this radially tapered surface means that, should the tube and hence the or each first tooth begin to be rotated about the axis, the radially tapered surfaces will cause the or each tooth to grip the tube more tightly thereby increasing the resistive force with the rotational force.

If the collet is to be non-rotatable within the body, this may be done by the collet engaging with features on the inside of the body. Alternatively, the connector may further comprise a bushing which has at least one leg which co-operates with the collet legs to prevent rotation of the collet. This bushing may provide the above mentioned component which is provided with the first teeth. As such, the bushing will serve both to carry the or each first tooth and also to prevent rotation of the collet.

As a further alternative, the collet is provided with features on the end faces of the legs which engage with complementary features that are fixed with respect to the body to prevent rotation of the collet. These complementary features may be provided directly on the body, or may be provided on a ring which has a set of teeth that engage with the housing to prevent rotation of the ring with respect to the housing.

It is not necessary for the collet to have teeth. If this is the case, the or each first tooth may assist the collect to some extent in resisting axial movement of the tube. However, preferably, the connector further comprises at least one second tooth, the second tooth being on the collet and having a gripping edge in the plane perpendicular to the axis. This enhances the ability of the collet to provide a resistance to axial movement of the tube.

A single first tooth will provide a reasonable degree of resistance to rotation. However, preferably, there are a plurality of discrete first teeth circumferentially spaced about the main axis. This provides a better distributed resistive force. When there is more than one first tooth, the first teeth on opposite sides of the connector may be coplanar. However, preferably, each first tooth is angled in the opposite sense to the first tooth on the opposite side of the connector. Effectively, when viewed from the side, looking down on a pair of opposite first teeth, the first teeth will cross one another in a X shape. Again, this provides for a better distributed resistive force and one which would not tend to generate a resultant axial force on the connector. The first tooth may not have a pair on the exact opposite side of the connector, for example if there are an odd number of first teeth. However, it is preferable that the first teeth are still angled in the opposite sense as compared to those teeth with are generally on the opposite side of the connector.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before describing the examples, the nomenclature used in the subsequent description will be explained. The connectors are generally tubular in nature and have a main axis X which also corresponds to the axis of a tube inserted into the connector. The connector has a mouth at one end into which the tube is inserted. The radial and circumferential directions are defined with respect to the axis X. The end with the mouth will be referred to as the proximal end and the opposite end is the distal end.

A First Example of a Connector is Shown inFIGS. 1 to 4.

This comprises a main body1having a generally tubular configuration centred on axis X and having a throughway2extending from the relatively wide mouth3at the proximal end to a narrow outlet4at the distal end. Within the throughway2approximately midway along the body1are a number of circumferentially arranged castellations5best shown inFIG. 2. These are arranged so that the diameter of the throughway is intermittently narrow at this point. Between the castellations5, there is a ramped surface6which represents a gradual decrease in the cross-section of the throughway2towards the distal end. The purpose of the castellations5and ramped surface6is described below. Towards the outlet4, the throughway2is provided with an annular shoulder7which represents a step-down in the cross-section and provides an end stop for the tube T as best shown inFIGS. 3 and 4. The proximal end of the body1is provided with a male screw thread8the purpose of which is described below.

The first component to be inserted into the throughway2of the housing1is an annular bushing10. This has an annular portion11at the proximal end from which a number of legs12project distally. These legs12correspond in number and size to the spaces between castellations5into which they fit. The outermost edge13of each of the legs12engages with the ramp6as best shown inFIGS. 3 and 4. Each of the legs12is provided with an angled tooth14. When viewed in the plan view, the tooth14is at an angle of approximately 45° with respect to the axis X as best shown inFIG. 1.

After the bushing10is inserted into the throughway2in the main body1, this is followed by an O-ring seal20which engages with the annular portion11of the bushing10and creates a seal between the tube T and the main body1. As can be seen fromFIGS. 3 and 4, the bushing10is on the same side of the seal20as the tube T and is referred to as the “wet” side.

Behind the O-ring20is a spacer ring21which abuts against the seal20.

Behind the spacer ring21is a collet30which has a conventional construction. This comprises an annular end portion31at the proximal end from which a number of legs32extend distally. Each leg32has an inwardly projecting second tooth33the cutting edge of which is in a plane perpendicular to the axis X in conventional fashion.

A locking ring40surrounds a central portion of the collet30and has a female screw thread41which engages with the male screw thread8on the connector1. In its initial configuration, the components of the connector are in the position shown inFIG. 3in which the locking ring40is not fully threaded onto the main body1. Thus, the components within the throughway are free to move axially to a small extent. With the connector in this configuration, the tube T is inserted into the throughway2until it lands on the shoulder7. Once it is fully engaged, the locking ring40is screwed down into the body1moving the components to the position shown inFIG. 4. As the locking ring40is screwed down, the ramped surface42engages with the legs32of collet30and moves them distally. This, in turn, pushes the spacer ring21, O-ring seal20and bushing10distally into the position shown inFIG. 4. The edges31of legs12of the bushing10run up ramp6and are forced inwardly thereby causing the angled teeth14to grip the tube T as shown inFIG. 4. The components are held in this position because the locking ring40prevents them from moving axially. Any axial force on a tube T in a direction pulling it out of the connector causes the second teeth33of the collet to grip the tube T more tightly as the legs are forced up the ramp42as is conventional with a collet of this type. In addition, any force tending to cause the tube T to rotate about the axis X is resisted by the angled teeth14.

As illustrated in the drawings, the sides of the castellations5and the corresponding legs12are in a generally radial plane. However, these surfaces could be inclined to this radial plane in the sense that any rotational force applied to the bushing10will cause the legs12to ride up these inclined surfaces thereby increasing the gripping force exerted by the angled teeth14as the tube is rotated in a similar manner to that in which the second teeth33of the collet provide an increased gripping force caused by the ramped surface42.

In order to remove the tube T from the connector, the locking ring40is unscrewed to the position shown inFIG. 3and the collet30is depressed into the connector such that the collet legs can expand radially free from influence by the ramped surface42. Similarly, the legs12of the bushing10are free to slide back up the ramp6again releasing the tube so that it can simply be pulled out of the connector.

A Second Example of a Connector is Shown inFIGS. 5-8.

In this, similar components will be designated with the same reference numerals, and only the differences are described in detail.

In the second example, the bushing10from the first example as well as the castellations5and ramps6are no longer present. Instead, the angled teeth14are provided on the collet30as best shown inFIG. 6. All of the teeth may be of the angled type. Alternatively, some may be angled, while some are conventional teeth33in the radial plane as shown inFIG. 6. In place of the bushing10, the second example uses features on the end of the collet and the spacer in order to prevent rotation. Thus, the spacer is provided with a plurality of teeth22on its radially outermost surface which engage with complimentary teeth23of an inner face of the proximal end of the main body1as best shown inFIG. 5. Once the spacer21is in place, the teeth22and23engage with one another preventing rotation of the spacer21. On the axial end faces of the spacer ring21are a number of circumferentially arranged protrusions24. As is apparent fromFIGS. 5 and 6, these are present on both faces of the spacer ring21. However, only those facing the collet are operative. They are provided on both sides so that the spacer21can be inserted either way up. Complementary protrusions34are provided on the distal end face of the collet30as shown inFIG. 6. These engage with the protrusions24on the spacer ring21so that the collet30cannot rotate in respect to the spacer21and hence with respect to the rest of the coupling. Although described as protrusions24,34, these could equally be recesses in one of the surfaces. The important requirement is that the two sets of features are complementary and prevent the relative rotation as described above.

With the components in the configuration shown inFIG. 7, the tube T is inserted. The locking ring40is then screwed into the position shown inFIG. 8causing the collet teeth to move inwardly and grip the tube as described above. This also causes the protuberances24and34to engage with one another therefore preventing rotation of the tube T.

A Third Example of a Connector is Shown inFIGS. 9-12.

This example is similar to the second example in that the angled teeth14are provided on the collet. The spacer21is provided with four proximally protruding legs25with enlarged ends26which land in U-shape recesses27in the proximal end face of the main body1. The legs32of the collet fit between these legs25such that the collet cannot rotate.

The locking ring40does not have a screw-thread, but is arranged to rotate through 900 with respect to the main body1, such that features43engage with the collet30and urge it away from the main body1. The distal end has an undulating profile44which selectively covers features45on the body1to provide a visual indication that the locking ring is at its locked positioned.

FIG. 10also illustrates how the angled teeth14on opposite sides of the connector are oriented. As can be seen inFIG. 10, the tooth on one side is angled in the opposite sense to the tooth on the other side such, if the two were viewed directly from the side, they would cross in an X shape.

A Fourth Example of a Connector is Shown inFIGS. 13-16.

The fourth example is similar in construction and operation to the first example, in that it has a bushing10with the angled teeth14. In the fourth example, rotation of the bushing10is prevented by a pair of projections15which fit into complementary keying slots16in the inner face of the proximal end of the main body1.

The operation of this connector is broadly the same as that of the first example. However, as best seen inFIGS. 15 and 16, the angled teeth14are closer to the mouth of the connector than they were in the first example. They are positioned in such a way that the ramp surface42on the locking ring40pushes them inwardly into the tube T as best shown inFIG. 16. Thus, the ramp surface42biases both the angled teeth14and the second teeth33on the collet (not shown inFIGS. 15 and 16as they are out of the plane of the section) into engagement with the tube T.