GB2323418A

GB2323418A - Squeeze to release female conduit coupling member

Info

Publication number: GB2323418A
Application number: GB9705902A
Authority: GB
Inventors: Nuri Djavit
Original assignee: Bristol Myers Squibb Co
Current assignee: Bristol Myers Squibb Co
Priority date: 1997-03-21
Filing date: 1997-03-21
Publication date: 1998-09-23
Anticipated expiration: 2017-03-21
Also published as: GB2323418B; GB9705902D0

Abstract

The female member 10 comprises a skirt 14 carrying one or diametrically opposed locking element(s) 20 for engaging a rib 22 of a male member 12, the skirt 14 being resiliently deformable to allow separation by squeezing the skirt. At least a portion of the skirt 14 is made of a first relatively deformable plastics material and the locking element(s) 20 and/or a structural portion 16, 34 is/are made of a second relatively stiff and hard plastics material, which can be made by a multi-shot moulding process. The shirt 14 can have finger buttons orthogonal to the element(s) 20. The shirt can be of circular or elliptical cross-section when undeformed.

Description

CONDUIT COUPLING This invention relates to a conduit coupling, i.e. a coupling for joining two conduits, and in particular to a squeeze-to-release coupling. The invention is particularly suitable for use in the medical and hygiene fields, for example, as an incontinence coupling, but the invention is not limited to such fields.

Many designs of squeeze-to-release couplings are known. For example, reference is made to US-A-5,466,017, US-A-5,213,376, US 4,844.512, US 3,990,727, GB 2,061,466 and JP-U-62 11610. Such couplings generally tend to have a complicated structure, on the one hand to balance the requirement for a secure mechanical interlock, and on the other hand for a resilient squeeze-to-release wall. Many prior art couplings include an integrally moulded resilient ring which is distinct from, and spaced axially from, the body of the female coupling member; such a ring can be vulnerable to damage or accidental release.

The present invention has been devised bearing such problems in mind.

In contrast to the prior art couplings in which the structural body of a coupling member is generally of a single material, the present invention, broadly speaking, provides a coupling member with first and second structural portions made of different plastics materials having different characteristics.

In one aspect, the present invention provides a conduit coupling comprising a female coupling member and a male coupling member, the female coupling member comprising a skirt carrying at least one locking element for engaging the male coupling member, the skirt being resiliently deformable to move the locking element to a non-engaging position to enable separation of the male and female coupling members, wherein at least a portion of the skirt is of a first relatively deformable plastics material, and wherein the locking element is of a second relatively stiff and hard plastics material.

In a second aspect, the invention provides a conduit coupling comprising a female coupling member and a male coupling member, the male coupling member comprising at least one structural portion of a first relatively stiff plastics material, and a skirt at least a portion of which is of a second relatively deformable plastics material, the skirt being resiliently deformable, in use, to enable the coupling to be unlocked, and the male and female coupling members separated.

During the work leading to the invention as defined in the above aspects, it was appreciated that the structure of the female coupling member may be considerably simplified by the use of a relatively stiff (or firm or rigid) plastics material in at least one portion of the coupling, and of a second relatively resilient or deformable plastics material for at least a part of a flexible skirt or cup portion of the coupling. In one embodiment, the female coupling member is formed with a generally continuous cup wall (at least around the majority of the periphery) which carries locking elements around its mouth. This avoids the need for any form of concentric locking ring in front of the mouth of the female member, as used in some examples in the prior art.

Furthermore, it has been appreciated that the use of first and second different materials can overcome disadvantages of using a single material as in the prior art arrangements.

For example, a wall consisting at least partly of resilient deformable material will usually have better resilient characteristics than an equivalent solid wall made entirely of relatively stiff material. Compared to the specific prior art designs identified above, the need for a discrete ring spaced from the main body of the connector can be avoided. Instead, a resiliently deformable skirt wall can be provided to integrally join the main body and the locking elements. The skirt wall can improve the resilient support of the locking elements by providing a return force (relative to the main body) around the entire periphery of the connector mouth, instead of relying only on the support provided by the discrete beams. Furthermore, the skirt wall can provide better stability of the connector mouth, and can provide better protection than arrangements in which a discreet ring is vulnerable to damage.

The skirt wall does not have to be continuous around its entire periphery. In the preferred embodiment apertures are provided in the skirt wall to assist in moulding the female connector.

Overall, the use of the first and second different materials can enable the connector to have "compound" characteristics in terms of strength and resilience, such characteristics being difficult (or prohibitively expensive or even impossible) to obtain with a single plastics material.

Preferably, the relatively deformable soft plastics material provides a resilient interior sealing surface in the female coupling member, for establishing a seal against the exterior surface of the male member when the coupling is assembled.

Preferably, the female coupling member has a rear extension of relatively firm plastics material, for fitting into the end of a tube with which the female coupling member is to be attached, in use.

In a closely related aspect, the invention provides a method of producing a squeeze-to-release female coupling member for use in the assembly of any preceding claim, the method comprising moulding at least a portion of a resilient skirt of first relatively deformable plastics material, and moulding a second structural or locking portion of second relatively rigid plastics material, using a multi-shot moulding process. The skirt and the second portion can be moulded in any order.

Embodiments of the invention are now described by way of example only, with reference to the accompanying drawings, in which: FIG. 1 shows schematically male and female coupling members of a first embodiment, the female coupling member being shown in cross-section; FIG. 2 is cross-section through the female coupling member along the line II-II of Fig. 1; FIG. 3 is a side view of the female coupling member in the same orientation as that shown in FIG. 2; FIG. 4 is a side view of the female coupling member in the same orientation as that shown in Fig. 1; FIG. 5 is an end view of the female coupling member in its normal condition; FIG. 6 is an end view similar to Fig. 5, but showing an elliptical deformation occurring during the squeeze-to-open action of the female coupling member; FIG. 7 is a side view of a female connector of a second embodiment; FIG. 8 is a underside view looking into the mouth of the connector; FIG. 9 is a side view of the female connector from an orthogonal direction; FIG. 10 is a schematic cross section along the line C-C of FIG. 9; FIG. 11 is a schematic cross section along the line B-B of FIG. 8; FIG. 12 is a schematic cross section along the line A-A of FIG. 8; FIG. 13 is a schematic cross section similar to FIG. 11. showing the male and female connectors when assembled; FIG. 14 is a schematic cross section similar to FIG. 12, showing the male and female connectors when assembled.

Referring to the drawings, the coupling consists of a female coupling member 10 for co-operating with a male coupling member 12. As best seen in FIGS. l and 2, the female coupling member 10 consists of a generally bell-shaped deformable cup or skirt portion 14 which is integrally moulded with a generally rigid rear extension 16. At its mouth, the skirt has an inner ring 19 carrying two inwardly projecting locking elements 20 diametrically opposed positions for latching engagement with an annular shoulder 22 on the male coupling member 12. The male coupling member 12 has a generally cylindrical nose which, in use, is inserted into the female coupling member 10.

The rear extension 16, the ring 19 and the locking elements 20 are made of a first type of plastics polymer, which is relatively stiff or firm. For example, a suitable polymer is polypropylene. The skirt portion 14 is made of a second type of plastics material which is soft or deformable. A suitable type of soft elastomer for the second material is a fully synthetic thermoplastic rubber, for example, the material "santoprene" obtainable from Advanced Elastomer Systems, of Unit l, Harcourt Way, Meridian Business Park, Braunstone, Leicester.

In use, the soft material of the skirt portion 14 enables the mouth of the female coupling member 10 to deform to permit locking assembly and manual separation of the coupling members.

Referring to FIGS. 1 and 5, in this embodiment, the natural shape of the mouth of the skirt portion 14 is circular. To assemble the coupling, the male coupling member is simply advanced into the female coupling member 10. As the male coupling member 12 approaches its fully connected position, the locking elements 20 will begin to bear on the annular shoulder 22. The locking elements 20 and the shoulder 22 have complementary ramp surfaces 24 to permit the locking elements 20 to ride over the shoulder 22 as the male coupling member 12 is pushed fully home into the female coupling member 10, to form a snap-together action.

During such action, the soft material of the skirt portion 14 permits the necessary deformation of the skirt, to enable the locking elements 20 to be displaced radially outwardly.

The locking elements 20 and the annular shoulder 22 have complementary rear abutment surfaces 26. In the fully engaged position of the male coupling member 12 within the female coupling member 10, the abutment surfaces 26 of the locking elements engage behind the abutment surface 26 of the annular shoulder 22, thereby preventing separation of the two coupling members. Since the ring 19 and the locking elements 20 are made of relatively rigid plastics material, there will be very little tendency for the locking elements 20 themselves to deform even if a substantial axial force is applied to try to withdraw the male coupling member 12 from the female coupling member 10. Therefore, the rigid nature of the coupling elements 20 provides a secure locking mechanism, in use.

In the fully engaged position, the interior surface 18 of the skirt portion 14 acts as a pliable sealing surface for establishing a seal against the cylindrical nose 21 of the male coupling element 12. In this embodiment, the interior diameter of the sealing surface 18 is made slightly smaller than the outer diameter of the cylindrical nose 21, so that good sealing contact will be established when the coupling members are assembled. It will be appreciated that the use of the soft material for the skirt portion 14 enables sufficient deformation to accommodate the cylindrical nose 21.

When it is desired to release the coupling members, the user merely has to apply a radial force to the skirt portion 14, to deform it to an elliptical shape. To facilitate this, the skirt portion 14 is provided with integral finger "button" areas 28, which project radially outwardly to indicate the positions at which a user should apply a squeezing force. As best seen in FIGS. 5 and 6, the buttons 28 are arranged orthogonally relative to the locking elements 20, such that, when a user applies a force to squeeze the buttons radially inwardly (as shown by arrows 30), the skirt (and the ring 19) deforms elliptically and the locking elements 20 are shifted radially outwardly (as shown by arrows 32). This moves the locking elements 20 clear of the annular shoulder 22, thereby releasing the locking engagement, and permitting the male coupling member 12 to be pulled free of the female coupling member 10.

As best seen in FIGS. 1-4, in the region of attachment of the rear extension 16 to the skirt portion 14, the rear extension 16 is bifurcated, and comprises two part-circular walls 34. The surface of the skirt portion 14 has a complementary profile, with islands 36 for mating with the part circular walls 34 of the rear extension 16. The part-circular walls 34 serve to reinforce the skirt portion 14 in the region of each locking element 20. It will be appreciated that there may be a tendency for the skirt portion 14 to deform outwardly if an axial separation force is applied to the coupling members while in their assembled condition. Such deformation might be sufficient to cause premature release of the locking elements 20, allowing accidental separation of the coupling members. However, the reinforcement provided by the part-circular walls 34 reduces the risk of this occurring.

On the other hand, the clearance 36 between the part-circular walls 34 allows a greater degree of deformation of the skirt portion 14 in the region of the finger buttons 28, so as not to hinder unnecessarily desired deformation when pressure is applied at the button positions. The reinforcement in selected regions thereby enhances the effectiveness and integrity of the coupling, while still permitting simple unlocking without requiring significant squeezing pressure.

The female coupling member 10 may be produced by a two-shot moulding process. For example, the skirt portion 14 could be moulded as a first stage and, before the plastics material has cured, the rear extension 16 and the locking elements 20 moulded onto the skirt portion 14 as a second moulding operation.

Such a two-shot moulding process relies on a chemical bond being established between the different plastics materials, and is known per se. It will also be appreciated that the different portions could be moulded in a different order.

An alternative moulding technique is to mould one of the portions first, and to allow the plastics material to cure before moulding a subsequent portion. With such a technique, the moulded portions would have to have mechanical interlocking or keying profiles, to ensure that the different portions are joined.

In the illustrated embodiment, the rear extension 16 has a tapered outer surface 40 for frictionally engaging the interior surface of a pipe 42 in which the rear extension 16 is a force fit. Although not illustrated, the male coupling member 12 may have a similar pipe-connecting extension.

Referring to FIGS. 7 to 14, a second embodiment is illustrate which is similar in principle to the first embodiment. The same reference numerals are used where appropriate to denote corresponding features.

A first difference in the second embodiment is that the skirt portion 14 is elliptical in its natural, unstressed condition. In order to release the coupling, pressure is applied at the positions denoted by the arrows 50 in FIG. 8, to deform the skirt towards a circular shape, causing the locking elements 20 to shift radially outwardly (indicated by arrows 52).

The elliptical shape can result in greater radial movement being generated than that possible with a circular shape having the same circumference. Thus, the distance through which the locking elements 20 need to move to clear the annular rib 22 can be greater, allowing a more sure coupling to be established when the locking elements are in their normal position. It will be appreciated that the resiliently deformable skirt 14 contributes to the effectiveness of this design by permitting the large degree of deformation when the skirt is squeezed.

A second difference is that the skirt portion 14 is not a continuous wall, but includes apertures 54 directly above, and in alignment with, the locking elements 20. The purpose of the apertures is to facilitate moulding by providing room for the mould parts (defining the interior shape of the female connector) to be withdrawn after the moulding operation has been completed. In particular, it will be appreciated that it would be difficult to extract axially a solid mould part shaped to define the abutment surface 26 of each locking element 20; the locking element would obstruct extraction through the connector mouth. However, the provision of apertures allows mould parts to be withdrawn (and inserted) radially through the wall of the connector.

A further difference is that the ring 19 carrying the locking elements 20 is on the exterior of the connector mouth, and is coupled to the rear extension 16 directly by exterior webs or legs 56. 58 of relatively stiff material. In particular two legs 56 are arranged radially opposite each other at diametrically opposed positions, and a pair of thinner legs 58 is arranged adjacent to each locking element 20. The legs 56 and 58 serve to further reinforce the support of the ring 19 and of the locking elements 20. Nevertheless, the resiliently deformable skirt 14 integrally moulded with the legs 56 and 58 can enhance the flexibility of the connector compared to a solid wall of rigid material being used. Moreover, the skirt can enhance the stability and resilience of the ring 19 and the locking elements 20, and reduce vulnerability, compared to a discreet ring being axially spaced away from the connector body and supported by discreet beams or limbs.

It will be appreciated that the present invention, particularly as illustrated in the preferred embodiments, can provide a squeeze-to-release coupling assembly which has a simple structure, is straightforward to use, and can achieve secure coupling engagement. The use of different plastics materials, integrally moulded to form a single member, enables the properties of soft plastics material to be exploited as a deformable skirt, and as a seal, and the properties of a more rigid or firm plastics material to be exploited for the locking elements, for non-deformable regions, and for structural reinforcement.

It will be appreciated that the above description is merely of an example of the invention, and that modifications of detail may be made within the scope and principles of the invention.

Features and aspects of the invention believed to be of particular importance have been highlighted in the foregoing description and attached claims. However, the Applicant claims protection for any novel feature or combination of features disclosed herein and/or illustrated in the drawings, irrespective of whether emphasis has been placed thereon.

Claims

1. A squeeze-to-release conduit coupling comprising a female coupling member and a male coupling member, the female coupling member comprising a skirt carrying at least one locking element for engaging the male coupling member, the skirt being deformable to permit release of the locking element from the male coupling member and thereby permit separation of the coupling members, wherein the skirt includes a first portion of a first relatively deformable plastics material, and wherein the locking element is of a second relatively firm plastics material.

2. A conduit coupling according to claim 1, wherein the skirt carries first and second locking elements at diametrically opposite positions.

3. A conduit coupling according to claim 1 or 2, wherein the skirt is generally circular in a normal configuration, and is deformable to a generally elliptical shape, in use, for releasing engagement of the or each locking element.

4. A conduit coupling according to claim 1 or 2, wherein the skirt is generally elliptical in a normal configuration, and is deformable towards a more circular shape, for releasing engagement of the or each locking element.

5. A conduit coupling according to claim 1, 2, 3 or 4 wherein the skirt carries one or more finger buttons at positions corresponding to the positions at which pressure is intended to be applied to release the coupling.

6. A conduit coupling according to claim 5, comprising first and second finger buttons at positions which are orthogonal to the position or positions of the one or more coupling elements.

7. A conduit coupling according to any preceding claim, wherein the female coupling member further comprises a rear extension of a relatively firm plastics material.

8. A conduit coupling according to claim 7, wherein the rear extension is of generally the same plastics material as the one or more locking elements.

9. A conduit coupling according to any preceding claim, wherein the male coupling element comprises an annular projection against which the one or more locking elements are engageable.

10. A conduit coupling according to any preceding claim, wherein the female coupling member comprises an interior sealing surface for establishing a seal with the male coupling member when the coupling members are assembled.

11. A conduit coupling according to claim 10, wherein the interior sealing surface comprises a surface of the portion of the skirt of relatively deformable plastics material.

12. A conduit coupling according to any preceding claim, wherein the relatively deformable plastics material is an elastomer.

13. A conduit coupling according to claim 1 or 2, wherein the skirt wall has one or more apertures therein.

14. A conduit coupling according to any preceding claim, further comprising one or more reinforcement limbs or regions of relatively stiff material extending to or towards the mouth of the female connector.

15. A conduit coupling according to any preceding claim, further comprising a ring of relatively rigid material for carrying the or each locking element.

16. A squeeze-to-release conduit coupling comprising a female coupling member and a male coupling member, the female coupling member comprising a structural portion or an engagement portion of a first relatively firm plastics material, and a skirt at least a portion of which is of a second relatively deformable plastics material, the skirt being resiliently deformable, in use, to release locking engagement with the male coupling member and thereby permit separation of the coupling members.

17. A method of producing a squeeze-to-release female coupling member for use in the assembly of any preceding claim, the method comprising moulding a first resilient skirt including at least a portion of first relatively deformable plastics material, and moulding a second structural or locking portion of second relatively stiff plastics material, using a multi-shot moulding process.

18. A method according to claim 17, wherein the process is a two-shot moulding process.

19. A method according to claim 17 or 18, wherein the second portion is moulded before said portion of the skirt.

20. A coupling, a female coupling member, or a method of production, substantially as hereinbefore described with reference to any of the accompanying drawings.

Amendments to the claims have been filed as follows ring of relatively rigid material for carrying the or each locking element.

17. A method of producing a squeeze-to-release female coupling member for use in the coupling of any of claims 1 to 15, the method comprising moulding a said resilient skirt including at least a portion of first relatively deformable plastics material, and moulding a said locking element of second relatively stiff plastics material, using a multi-shot moulding process.

18. A method of producing a squeeze-to-release female coupling member for use in the coupling of claim 16, the method comprising moulding a said structural portion or an engagement portion of a first relatively firm plastics material, and moulding a said skirt including at least a portion of a second relatively deformable plastics material, using a multi-shot moulding process.

19. A method according to claim 17 or 18, wherein the process is a two-shot moulding process.

20. A method according to claim 17, 18 or 19 wherein the relatively stiff plastics material is moulded before the moulding of the relatively deformable portion.

21. A coupling, a female coupling mcmber, or a method of production, substantially as hercinbcfore described with rcfercncc to any of the accompano ing drawings.