GB2072288A

GB2072288A - Connectors for tubing

Info

Publication number: GB2072288A
Application number: GB8106608A
Authority: GB
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 1980-03-11
Filing date: 1981-03-03
Publication date: 1981-09-30

Abstract

A medico-surgical connector arranged to make fluid connection between one end of a tube 4, such as an epidural cannula, and, for example, the nose 5 of a syringe 6. The connector has an elastomeric tubular inner member 2 with an axial passage 25 within which the tube is inserted. The inner member is retained at either end 21 and 24 within respective tubular outlet members 1 and 3 of a rigid plastics material. The outer members can be angularly displaced relative to one another, thereby twisting and elongating the inner member to distort its passage into sealing contact about the tube. The outer members have cooperating ratchet teeth 16 and 30 which serve to lock the outer members, with the inner member in a distorted state. One of the outer members 3 is formed with luer-tapered bore 37 that is in communication with the passage through the inner member and that receives the nose of the syringe. <IMAGE>

Description

SPECIFICATION Connectors This invention relates to connectors for enabling fluid connection to be made between two tubular members.

The invention is more especially concerned with connectors for making connection with tubing used for medical purposes. In this respect, the invention is of especial advantage in enabling connection of a luer-tapered member, such as, the nose of a syringe, to be made with a smalldiameter tube such as an epidural cannula.

In order to make connection with a small diameter tube such as an epidural or intravenous cannula, it is usually necessary to provide some form of connector, one end of which receives a larger diameter tube or tubular member. It is an advantage to use a connector that can be readily removed from the end of the small diameter tube since this enables the tube to be connected to other tubes of different sizes by use of different connectors. A removable connector also enables the same connector to be used on a tube that has been shortened by cutting.

It is an object of the present invention to provide a connector of simple and compact construction that can provide an effective seal with a tube and that is readily removable.

According to the present invention there is provided a connector for making fluid connection between first and second tubular members, wherein the connector includes an elastomeric member having a passage therethrough that opens at one end of the connector, said passage being arranged to receive an end of the first tubular member, wherein said elastomeric member has first and second portions arranged for angular displacement relative to one another about the axis of the passage such as to distort said elastomeric member and thereby urge a part at least of said passage into sealing contact with the surface of the first tubular member, wherein said connector is arranged such that said elastomeric member can be maintained in a distorted state, and wherein the other end of said connector is arranged to receive an end of said second tubular member in sealing engagement, such as to establish fluid connection between said first and second tubular members.

The seal with the first tubular member is formed by contact of the elastomeric member about the entire circumference of the first tubular member thereby ensuring an effective fluid-tight seal. The angular distortion of the elastomeric member establishes a torsional couple within the elastomeric member. The properties of elastomeric material are such that this torsional couple produces an elongation of the elastomeric member and consequently produces a seal with the tubular member along a greater length than would otherwise be the case.

The first and other portions of the elastomeric member may be opposite ends thereof. The connector may include a forward outer member and a rear outer member, the forward and rear ends of the elastomeric member being mounted within the respective forward and rear outer members. The forward and rear outer members may be provided with cooperating ratchet teeth which serve to maintain the forward outer member angularly displaced relative to the rear outer member.

The elastomeric member may be formed by moulding within the outer members.

A connector in accordance with the present invention, will now be described with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional elevation through the connector; Figures 2, 3 and 4 are perpective views of parts of the connector; Figures 5 and 6 are end views showing two modified forms of the connector; and Figure 7 is an elevation view showing another form of connector.

The connector comprises three components: an outer, tubular forward member 1 of rigid plastics material; an intermediate inner member 2 of a resilient elastomeric material; and an outer, tubular rear member 3 of rigid plastics material.

An epidural cannula 4 is inserted in the connector from its forward end and is gripped in sealing engagement by rotating the forward member 1 relative to the rear member 3. The rear member 3 enables connection to be made with the luertapered nose 5 of a syringe 6.

The forward member 1 has a generally cylindrical outer surface with flat sides 7 and 8 (Fig. 2). The forward end of the forward member 1 has a bevelled edge 10 and a flared aperture 11 that opens into the interior 12 of the member. The interior 12 is generally cylindrical and is shaped to receive within it the forward end of the intermediate member 2. At its rear end, the forward member 1 has a cylindrical nose portion 15 of reduced outer diameter which projects within the forward end of the rear member 3.

Forwardly of the nose portion 1 5, the outer surface of the forward member 1 is formed with two rearwardly-extending ratchet teeth 16. Each tooth 16 has a straight edge that extends along the curved surface of the member 1, and an inclined edge that extends between the two teeth, around the member. The teeth 16 act as a ratchet in the manner described in greater detail later.

The forward member 1 is also formed with a frusto-conical aperture 17 which extends outwardly from the interior 12 of the member. A cylindrical depression 18 is provided opposite the aperture 1 7 within the forward member 1.

The intermediate member 2 is of a generally Hshape (Fig. 3) having a cylindrical central portion 20 that extends as a close fit within the interior 12 of the forward member 1. The central portion 20 is terminated at its forward end by an upright portion 21, one end 22 of which projects as a close fit within the frusto-conical aperture 1 7, and the other end 23 of which similarly engages the depression 1 8. The rear end of the intermediate portion 2 is formed with a similarly shaped upright portion 24 which is a close fit within the rear member 3. An axial bore 25 extends through the intermediate portion 2, between its ends, and is aligned, at its forward end, with the aperture 1 1.

The rear member 3 has, at its forward end, a cylindrical outer surface with flat sides 26 and 27 (Fig. 4). The forward end of the rear member 3 embraces the nose portion 15 of the forward member 1, and is formed with two forwardlyextending teeth 30 which engage with the teeth 16 on the forward member 1. The rear member 3 has a hollow interior 31 that opens at its forward end and that is shaped to receive the rear end of the intermediate member 2. In this respect, the rear member 3 includes a frusto-conical aperture 32 which receives the similarly shaped end 33 of the rear upright portion 24. The inner surface of the rear member 3 is also formed with a cylindrical depression 34 which receives the other end 35 of the rear upright portion 24. A short bore 36 extends rearwardly of the interior 31, in axial alignment with the bore 25 through the intermediate member 2.The bore 36 in the rear member 3 is of the same diameter as the bore 25 in the intermediate member 2 and communicates with a luer-tapered bore 37 via an inwardly directed annular lip 38. The luer-tapered bore 37 opens at the rear of the rear member 3 and is formed as the interior of a reduced-diameter cylindrical portion 39 at the rear of the rear member.

In use, the epidural cannula 4 is inserted as a close fit through the bore 25 into abutment with the lip 38. The rear member 3 is then rotated in a clockwise direction relative to the forward member 1 so that the inclined edges of the teeth 16 and 30 move over one another and thereby force the foward and rear members apart against the resilience of the intermediate member 2. The forward and rear members 1 and 3 are rotated by 1800 relative to one another, that is, until the two members snap together with their teeth 16 and 30 in engagement at the next position. In doing this, the central portion 20 of the intermediate member 2 is twisted. It is a property of elastomeric materials that a torsional couple causes elongation along the couple axis.The torsional couple acting on the central portion 20 thereby causes elongation along its axis and consequently causes the bore 25 to be constricted about the cannula 4. The elongation produced in the intermediate member 2 enables contact with the outer surface of the cannula 4 to be made over a greater length than would otherwise be the case The elongation produced will also have the effect of keeping the forward and rear members 1 and 3 slightly apart when twisted, unless the intermediate member 2 is held in axial tension in its untwisted state. Providing the teeth 16 and 30 are large enough, this separation between the members need not impair efficient working of the connector.

The connector is maintained in fluid-tight sealing engagement with the cannula 4 whilst the teeth 16 and 30 are engaged in the twisted state.

Depending on the nature of the intermediate member 2 the connector could be locked on the catheter 4 by twisting through a greater angle, such as, 3600 or 5400. To remove the cannula 4, the forward and rear members 1 and 3 are pulled apart thereby allowing the resilience of the intermediate member 2 to rotate the forward and rear members back to their original position.

The connector is preferably made by assembling the forward and rear members 1 and 3 together and then moulding in the intermediate member 2. This is done by positioning a cylindrical mandrel to extend axially through the forward and rear members 1 and 3 so as to define the bore 25 through the intermediate member 2. Rubber solution is then poured into the assembly through one or both of the apertures 17 or 32. When the rubber solution has set the mandrel is removed leaving the intermediate member 2 moulded in position.

It will be appreciated that the connector could be modified in various different ways. For example, a greater number of teeth could be provided, or the teeth could be located closer together so that the amount of rotation needed to lock the connector with a tube is thereby reduced.

Alternative arrangements for maintaining the forward and rear members 1 and 3 in a rotated position, and the intermediate member in a distorted state, are also envisaged. The two members could, for example, be provided with cooperating castellated ends so that, by pulling apart then rotating, and pushing together, they could be held locked in a rotated configuration. Other arrangements such as, for example, where the two members have various other forms of co-operating surface formations could also be used.

The intermediate member could also be of different forms. More particularly, the intermediate member 2 need not necessarily be of H-shape but could instead be of another shape suitably arranged to key with the forward and rear members 1 and 3 without slipping upon relative rotation between them. The intermediate member could, for example, be of a general dumbell shape having enlarged cylindrical end portions, the surfaces of which have projections or indentations which key with the inner surface of the forward and rear members 1 and 3. The intermediate member 2 could be formed separately and subsequently assembled with the forward and rear members 1 and 3; in this way, it would be possible to maintain the intermediate member in axial tension and prevent the forward and rear members being separated by elongation of the intermediate member on twisting.

The connector could readily be adapted to enable two tubes of the same diameter to be connected with one another. To do this, the two tubes could be inserted into the bore 25 through the intermediate member 2 from opposite ends until they abutted one another. Rotation of the forward and rear members would then distort the wall of the passage through the intermediate member into contact with the outer surface at the ends of both tubes.

The flat sides 7 and 8 on the forward member 1, and 26 and 27 on the rear member 3 facilitate gripping and rotation of the forward and rear members. The connector may be differently shaped on its outer surface to facilitate rotation or axial separation of the forward and rear members 1 and 3. For example, the forward and rear members 1 and 3 may be of oval shape, as shown in Figure 5. Alternatively, the forward and rear members 1 and 3 may be of circular cross-section and be provided with axial grooves 40, as shown in Figure 6. Axial separation of the two members 1 and 3 can be made easier by providing annular grooves 41 about the connector, of the kind shown in Figure 7.

The bore 25 through the intermediate member 2 may have a ribbed or other surface chosen to improve the seal with the surface of the tube extending within it.

Claims

1. A connector for making fluid connection between first and second tubular members, wherein the connector includes an elastomeric member having a passage therethrough that opens at one end of the connector, said passage being arranged to receive an end of the first tubular member, wherein said elastomeric member has first and second portions arranged for angular displacement relative to one another about the axis of the passage such as to distort said elastomeric member and thereby urge a part at least of said passage into sealing contact with the surface of the first tubular member, wherein said connector is arranged such that said elastomeric member can be maintained in a distorted state, and wherein the other end of said connector is arranged to receive an end of said second tubular member in sealing engagement, such as to establish fluid connection between said first and second tubular members.

2. A connector according to Claim 1, wherein said first and second portions are opposite ends of said elastomeric member.

3. A connector according to Claim 1 or 2, including a forward outer member and a rear outer member, wherein the forward end of said elastomeric member is mounted within said forward outer member, and wherein the rear end of said elastomeric member is mounted within said rear outer member.

4. A connector according to Claim 3, wherein said forward and rear outer members are of generally tubular shape.

5. A connector according to Claim 3 or 4, wherein said elastomeric member is of a generally tubular shape having surface formations at its ends, said formations being arranged to key with cooperating internal surface formations in the respective forward and rear outer members.

6. A connector according to any one of Claims 3 to 5, wherein said forward and rear outer members are provided with cooperating ratchet teeth arranged to maintain the forward outer member angularly displaced relative to the rear outer member against the resilience of said elastomeric member.

7. A connector according to Claim 6, wherein said ratchet teeth are disposed such as to maintain said forward and rear outer members angularly displaced by a multiple substantially of 1 800 relative to one another.

8. A connector according to any one of Claims 3 to 7, wherein the outer surface of said forward and rear outer members are shaped such as to facilitate gripping and relative angular displacement of the outer members.

9. A connector according to Claim 8, wherein said outer members are formed with flattened surfaces along their length.

10. A connector according to any one of the preceding claims, wherein said passage is arranged to receive said first tubular member along the entire length of said passage.

1 1. A connector according to Claim 10, wherein said rear outer member is provided with a short bore that is aligned with said passage, said bore being arranged to receive an end of said first tubular member projecting from said elastomeric member.

12. A connector according to any one of the preceding claims, wherein the other end of said connector is provided with a luer-tapered bore arranged to receive a corresponding luer-tapered portion of said second tubular member.

13. A connector according to Claim 12 and any one of Claims 3 to 9, wherein said luer-tapered bore is formed in said rear outer member.

14. A connector according to any one of Claims 3 to 9, or Claim 13, wherein said elastomeric member is formed by moulding within said forward and rear outer members.

15. A connector according to any one of Claims 3 to 9, 13 or 14, wherein said outer members are of a plastics material.

16. A medico-surgical connector according to any one of the preceding claims.

17. A connector substantially as hereinbefore described with reference to Figures 1 to 4 of the accompanying drawings.

18. A connector substantially as hereinbefore described with reference to Figures 1 and 3, and any one of Figures 5 to 7.

19. A connector assembly including a connector according to any one of the preceding claims, and said first tubular member extending within said passage.

20. A connector assembly including a connector according to any one of Claims 1 to 18, and said second tubular member connected with said other end of said connector.