GB2454473A

GB2454473A - Locking ring for coupling assembly

Info

Publication number: GB2454473A
Application number: GB0721791A
Authority: GB
Inventors: Stephen John Dilks; Martin John Bailey
Original assignee: EUROPOWER HYDRAULICS Ltd
Current assignee: EUROPOWER HYDRAULICS Ltd
Priority date: 2007-11-07
Filing date: 2007-11-07
Publication date: 2009-05-13
Also published as: GB0721791D0

Abstract

A male body 20 is secured within a female body 10 inlet by e.g. radially outwardly biased collar segments 30 which engage a male body groove 22. A locking cap 40 retains the collar segments within the groove when partially inserted into the inlet and is retained therein by security element 60 which is mounted in or over a recess 29 in the male body between an upstand 28 and the groove. The security element can be resiliently compressed into the recess to allow the locking cap to be positioned concentrically therearound prior to insertion of the locking cap and to automatically expand beyond the recess to provide a non-return stop once inserted. The security element can be a part circular resilient band with longitudinal slots 62 in one edge defining tabs 64, 68, some of which 68 are compressibly deflected outwardly, can be a coiled resilient band or can be formed of two parts, at least one being resiliently compressible, e.g. into a depression provided in the other.

Description

P119374GB

COUPLING ASSEMBLY

The present invention is concerned with coupling assemblies for the connection of fluid conduits.

BACKGROUND

In the applicant's earlier WO 02/073079 and WO 2005/071304, couplings are described which retain in sealing engagement a first body, such as a housing, manifold or valve block, and a second body, such as a pipe or other conduit.

Accompanying figures 1 and 2, which are longitudinal cross sectional views, show a specific prior art coupling arrangement where the first body 10 is provided with an inlet or cavity 12 into which an end portion of the second body 20 is inserted. One or more deformable or moveable securing members 30 are mounted within the inlet 12 and serve to inter-engage the first and second bodies 10, 20. In this respect, portions of the securing member or members 30 engage with features of the second body 20 which have a different diameter from the general diameter of the body, for example, either a raised shoulder around the circumference of a pipe or a groove there around.

In this illustrated example, a groove 22 is provided in the pipe 20 and the securing members are in the form of three substantially identical locking collar segments 30 a, b, c, best seen in figure 3, which is a tranverse section along the line A-A in figure 1. These locking collar segments 30 a, b, c are of rigid material and they are resiliently biased outwardly by a resilient discontinuous band 38, such as a coil spring, so that radially enlarged rear portions 32 of each segment 30a, b, c are retained within a recess 14 in the wall of the inlet 12. Such rigid securing segments are necessary when the coupling is in respect of a fluid conduit for conveying high pressure mediums, for example hydraulic or pneumatic power supplies. The locking segments 30a, b, c also have respective radially inward projections 34 whereby they engage the said groove 22 in the pipe 20 upon coupling engagement, as will be explained shortly in greater detail. The locking collar segments 30 a, b, C, also have an externally tapered front edge 36.

The sealing function between the bodies 10 and 20 is performed by one or more flexible or elastomeric sealing members, such as "0" ring seals 24 shown in figures 1 and 2 mounted in a further groove 26 near the insertion end of the second body 20.

P119374GB In other known embodiments of couplings of this general type a single securing member of a delormable material, or a single discontinuous securing member such as a split ring may be employed when the coupling is for use in a conduit for conveying fluid in a low pressure environment.

The prior art coupling arrangement also comprises a locking cap 40, in the form of a sleeve which is an easy sliding fit on the second body (pipe) 20, for retaining the securing means 30 in engagement with the second body 20 thereby locking the end of the second body 20 within the inlet 12 of the first body 10. This cap 40 has a generally cylindrical leading portion 44 for insertion into the inlet 12 and a radially outwardly directed flange 42 at its trailing end for abutment against the face of the first body 10.

The leading portion 44 has a tapered front face 46 on its inner surface. The cap 40 is formed of a plastics material moulding and a series of resiliently deflectable tabs 47 are integrally moulded around the circumference of the cylindrical portion 44. Each tab 47 has a terminal claw 48 which resiliently clicks into place in a groove 16 in the first body when the cap 40 is pushed fully home to the position shown in figure 2, with its flange 42 in abutment against the face of the first body 10.

In operation, in order to join the two bodies 10, 20 together in a secure fashion the locking cap 40 is firstly slid to a position where its flange 42 abuts an annular upstand 28 for that purpose, as shown in figure 1. The end of the second body 20 is then inserted into the first body 10 in the direction of the arrow E in Figure 1 until it is fully into the base of the inlet 12 of the first body 10, abutting a shoulder 18 which defines the base of the enlarged region which constitutes the inlet 12. To reach this position, the end of the pipe has passed through the central opening defined by the three locking collar segments 30 a, b, c. Facilitated by a tapering front face of the radial inward projections 34, the end region of the pipe pushes the collar segments radially outwards further into the recess 14 until the radial inward projections 34 of the collar segments fall into the groove 22.

Only at this point is the locking cap 40 pushed along the pipe 20 in the direction of the arrow E and thereby inserted into the inlet 12 in the first body 10. The tapered front face 46 of the cylindrical leading portion 44 of the cap 40 engages and then slides over the tapered front edge 36 of the collar segments 30 a, b, c so that the entire cylindrical leading portion 44 moves down between the wall of the inlet 12 and the exterior of the collar segments 30 to the position shown in figure 2. In this position the claws 48 on the P119374GB cap 40 have clicked into the groove 16 and the flange 42 abuts the face of the first body 10. Also in this position the collar segments 30 a, b, c have been forced inwards against spring bias of the band 38 so that their radiaUy inward projections 34 are securely retained in the groove 22 in the pipe 20. This results in a secure connection between the first and second bodies 10, 20.

The cap 40 is provided with additional "0" ring seals 49 to prevent ingress of dirt or debris.

In order to disassemble the coupling shown in Figure 2, the cap 40 can be withdrawn from the inlet 12 of the first body 10 by inserting a tool such as a screwdriver blade or a special purpose-made tool between the face of the first body 10 and the underside of the flange 42 of the cap 40. Once the cap 40 has been prised away from the first body in this manner the locking collar segments 30 will release the end of the pipe 20 upon application of limited outward force on the pipe 20.

WO 02/073079 discloses in figure 11 how a dr-clip may be fitted to the pipe 20 behind an inserted member comparable to the locking cap 40 for added security.

In relation to the specific prior art arrangement of figures 1 to 3, in order that users can be assured that a secure connection has been made, an extra clip 50 has been provided for fitting in between the cap 40 (after it has been pushed home into the body 10) and the annular upstand 28 on the second body 20. This is a large coloured C-shaped plastic clip, as shown in figure 2. It may have an integral lug 52 to serve as a hand grip to facilitate fitting and removal. Not only does this provide a visual indication that the cap is fully pushed home, it also prevents any possibility of the cap 40 working free during operation, i.e. passage of fluid through the coupled conduit., for example by excessive vibration.

This clip 50 is, of course, intended to be fitted around the pipe 20 only the pipe 20 has been connected to the first body 10 as described above, first being fully pushed into the end of the enlarged inlet 12, then the cap 40 slid into its insertion position and pushed home.

Unfortunately, particularly where these couplings need to be disconnected and reconnected frequently, operatives have not been following this procedure and have P119374GB been fitting the clip 50 onto the pipe 20 between the cap 40 and the upstand 28 before the pipe 20 is inserted into the inlet 12. In other words, looking at Figure 1, the cap 40 has been displaced to the left and the 50 inserted behind it. This has the effect of preventing proper interconnection taking place. With reference to Figures 1 and 2 again, if the cap 40 is in a more forward position (i.e. to the left in figure 1) because the clip 50 has already been located behind it, its tapered front face 46 will engage behind the collar segments 30 (between the collar segments 30 and the wall of the inlet 12) earlier than in the correct coupling procedure. This forces the collar segments 30 to move inwards and grip the pipe 20 before the pipe has reached a position where its end abuts the shoulder 18 and prevents the pipe from moving to that position. When the cap is then slid along the pipe 20 in the direction E and into the the inlet 12, the tabs 47 are pressed inwards so there is a slight clicking sound which suggests that a connection has been made. In fact, the claws 48 have not yet reached a position where they can correctly engage into the groove 16 (as in the correct engaged position shown in figure 2) and the flange 42 at the top of the cap 40 does not abut the outside face of the first body 10. A slight gap remains. Overall the connection has not been securely made between the first and second bodies. Since these couplings are used in situations where fluids are conveyed under high pressure, this risks leakage of fluid and is generally undesirable.

The broad aim of the invention is to deal with this problem. More specifically, the object is to replace the clip, which can be misused as just explained, or can be mislaid when not fitted, by some sort of automatic indicator/lock which only becomes effective when the cap is pushed home in the correct manner.

BRIEF SUMMARY OF THE DISCLOSURE

The present invention provides a coupling assembly comprising a first body and a second body adapted for interconnection, the first body being provided with an inlet for receiving an end portion of the second body and the second body being of tubular form and having a portion, for engagement purposes, with an external diameter different from the remainder of the second body and also having an upstand at a spacing from its end at a distance beyond said different diameter portion, securing means for securing said second body end within said inlet, said securing means being located within the inlet and serving to engage the second body at said different external diameter portion thereby to secure said second body end within said inlet, and a locking cap in the form of a sleeve on the second body P119374GB for retaining the securing means in engagement with the second body and thereby assisting locking the second body end within the inlet of the first body, said locking cap being moveable longitudinally relative to the end portion of the second body in order to be partially inserted into the inlet where it is able to hold the securing means in its second body engaging position, and an additional security element capable of being mounted on the second body behind the locking cap in the direction of insertion of the second body into the inlet in the first body and between the locking cap and the upstand on the second body.

However, in contrast to known coupling arrangements the coupling assembly of the present invention is characterised in that the second body is formed with an annular or part-annular recess at the side of the upstand adjacent the locking cap, and in that the additional security element is mounted at least partially in or over said recess and is at least partly deformable such that it is capable of being resiliently compressed into said recess in order to allow the locking cap to be positioned concentrically there around prior to insertion of the locking cap into the inlet of the first body, yet automaticaUy expands to project beyond the recess and act as a stop for the locking cap when the locking cap is moved longitudinally of the second body to be inserted into the inlet.

Three different specific embodiments are proposed.

In the first, the additional security element is in the form of a part circular band of resilient material, said band being provided with a series of longitudinal slots in one edge to define there between a series of circumferential tabs, at least some of which are deflected outwardly relative to the others, but can be compressed into alignment with the others.

In the second, the additional security element is in the form of a coiled band of resilient material.

In the third version, the additional security element is formed of two parts, at least one of which is resiliently compressible. Preferably the first part locates in the recess and provides a depression facing outwards of the recess, and the second part is of resilient material, is located radially outwards of the first part and is compressible to P119374GB locate into the depression in the first part.

However, other versions may be possible within the scope of the general concept of the invention.

The invention will be described further, by way of example, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a fragmentary longitudinal cross section of a known prior art coupling assembly which has already been described above, the first and second (female and male) parts being shown prior to interconnection; Figure 2 shows the same parts as in figure 1 when connected and how an additional security element and indicator in the form of a clip is known for fitting onto the second body behind the locking cap; Figure 3 is a transverse section along the line A-A in figure 1 to illustrate the three locking collar segments and the band which biases them outwards into engagement with the recess in the inlet of the first body; Figure 4 is a view similar to figure 2 but to a somewhat enlarged scale and showing a first embodiment of a coupling assembly in accordance with the invention, in which a novel form of additional security element and indicator is employed; Figures 5 and 6 are reduced scale side views of just the second body (male part) of the coupling assembly of figure 4 showing the two alternative positions of the locking cap and additional security element; Figure 7 is an enlarged perspective view of the second body in the position shown in figure 6, with the additional security element operational; Figure 8 is a fragmentary perspective view illustrating a second embodiment in accordance with the invention; P119374GB Figure 9 is a fragmentary perspective view illustrating a third embodiment in accordance with the invention; and Figure 10 is a fragmentary perspective view illustrating a fourth embodiment in accordance with the invention.

DETAILED DESCRIPTION

Insofar as the embodiments of the invention are the same as the prior art, the description above will not be repeated and the same reference numerals have been allocated to the corresponding parts of the coupling assembly shown in figures 4 to 10.

Referring to figures 4 to 7, in a first embodiment in accordance with the invention, the second body 20 is formed with an annular recess 29 at the side of the upstand 28 adjacent the locking cap 40. Instead of the clip 50, a different form of additional security element 60 is provided. It is in the form of a part circular (i.e. discontinuous) band of resilient material, such as metal or plastics. This band has a series of longitudinal slots 62 cut or moulded into one edge to define there between a series of circumferential tabs 64, 68. Alternate first tabs 68 are deflected outwardly relative to the other second tabs 64, which maintain a generally cylindrical configuration. By virtue of the resilience of the band and its material, the first tabs 68 can be compressed into alignment with the second tabs 64.

As best shown in figure 4, this element 60 is mounted substantially in the recess 29 with only the deflected tabs 68 standing proud of the adjacent surface of the pipe 20.

However these tabs 68 are capable of being resiliently compressed into said recess 29 in order to allow the locking cap 40 to be positioned concentrically there around, abutting the upstand 28, as previously described in relation to figure 1 of the prior art, and as shown in figure 5, prior to insertion of the locking cap 40 into the inlet 12 of the first body 10. When the coupling is to be made and the locking cap 40 is slid along the pipe to engage in to the inlet 12 in the first body 10 (direction E in figure 1), the tabs 68 automatically return to their uncompressed state projecting proud of the recess 29 and act as a stop for the locking cap 40, as shown in figures 4, 6 and 7.

The element 60 can remain fitted to the pipe 20, located in the recess 29, so is not at risk of being mislaid like the previous clip 50. It operates automatically as both an P119374GB additional security lock and, particularly if coloured, as an indicator that the coupling has been corrected connected. So long as the locking cap 40 starts from a position overlying the element 60, as in figure 5, upon first connection of the coupling assembly, then, for disconnection, the cap 40 can only be pulled back when the tabs 68 of this indicator/lock element 60 are compressed back into the underlying groove 29. That can be done by a special encircling tool. Accordingly it does not allow for misuse leading to incorrect coupling as was possible with the plain clip 50 (as explained above).

Figure 8 illustrates a second embodiment of the invention where the additional security element is in the form of a coiled band 70 of resilient material, again possibly metal or plastics material. An inner part of the coil 70 retains the element in the recess 29, while an outer part, in a relaxed condition, extends beyond the recess 29, proud of the adjacent pipe surface, but can be compressed to locate fully in the recess when the locking cap 40 is slid back to lie there over, Its operation and advantages are otherwise the same as described for the first embodiment.

Figure 9 illustrates a third embodiment of the invention where the additional security element is formed of two parts, 80, 82. The first part is a part circular band 80 which locates in the recess 29 and provides a depression 81 facing outwards of the recess 29. The second part is also a part circular band 82, but of a more resilient materia' than the first band 80. The second band 82 is located radially outwards of the first band and is compressible to locate into the depression 81 in the first band 80, and thus lie fully within the recess 29. Operation and advantages of this embodiment are again the same as described for the first embodiment. This time only the outer band 82 needs to be compressed.

Figure 10 illustrates a variant where a band 84 similar to the outer band 82 in figure 9 surrounds a compressible C -clip 86, and both can be compressed into locating within the recess 29 when the locking cap is slid back to overlie them and abut the upstand 28.

The foregoing embodiments are only illustrative and the principles of the invention can equally be applied to other types of coupling assembly, different in detail from the version illustrated here as prior art. For example, as mentioned in the introduction, in other known proposals for couplings a single securing member, P119374GB which may be of deformable material, may be used in place of the separate rigid locking segments 30. Also, as disclosed in the applicant's earlier WO 03/0297 1 6 the leading end portion of the locking cap may project, upon coupling, to the inside of the securing member(s) (instead of to the outside in the version shown in figures 1 and 2), between said securing member and the second body. The inventive concept of the additional security element as automatic secondary lock/indicator, as described in the foregoing, can just as well be applied to these types of known coupling arrangement. Also many other variations in the specific details of the structure and engagement of the parts of the coupling assembly are possible, within the scope of the invention, as will be readily apparent to a person skilled in this

technical field.

Features, described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

Claims

P119374GB CLAIMS

1. A coupling assembly comprising: a first body and a second body adapted for interconnection, the first body being provided with an inlet for receiving an end portion of the second body and the second body being of tubular form and having a portion, for engagement purposes, with an external diameter different from the remainder of the second body and also having an upstand at a spacing from its end at a distance beyond said different diameter portion; securing means for securing said second body end within said inlet, said securing means being located within the inlet and serving to engage the second body at said different external diameter portion thereby to secure said second body end within said inlet; and a locking cap in the form of a sleeve on the second body for retaining the securing means in engagement with the second body and thereby assisting locking the second body end within the inlet of the first body, said locking cap being moveable longitudinally relative to the end portion of the second body in order to be partially inserted into the inlet where it is able to hold the securing means in its second body engaging position; and an additional security element capable of being mounted on the second body behind the locking cap in the direction of insertion of the second body into the inlet in the first body and between the locking cap and the upstand on the second body; characterised in that the second body is formed with an annular or part-annular recess at the side of the upstand adjacent the locking cap; and in that the additional security element is mounted at least partially in or over said recess and is at least partly deformable such that it is capable of being resiliently compressed into said recess in order to allow the locking cap to be positioned concentrically there around prior to insertion of the locking cap into the inlet of the first body, yet automatically expands to project beyond the recess and act as a stop for the locking cap when the locking cap is moved longitudinally of the second body to be inserted into the inlet.

2. A coupling assembly according to claimi wherein the additional security element is in the form of a part circular band of resilient material, said band being provided P119374GB with a series of longitudinal slots in one edge to define there between a series of circumferential tabs, at least some of which are deflected outwardly relative to the others, but can be compressed into alignment with the others.

3. A coupling assembly according to claimi wherein the additional security element comprises a coiled band of resilient material.

4. A coupling assembly according to claimi wherein the additional security element is formed of two parts, at least one of which is resiliently compressible.

5. A coupling assembly according to claim 4 wherein the first part locates in the recess and provides a depression facing outwards of the recess, and the second part is of resilient material, is located radially outwards of the first part and is compressible to locate into the depression in the first part.

6. A coupling assembly substantially as hereinbefore described with reference to and as illustrated in Figures 5 to 8, or any one of Figure s 9, 10 or 11 of the accompanying drawings.