GB2106208A - Tube connection - Google Patents

Abstract

A tube connection includes a flexible tube (1) with an abutment section (2) which engages with a part (6) of a rigid member (5). A locking ring (7) may be slid axially along the tube (1) to permit easy engagement or disengagement of the tube with the rigid member in a first position (not shown), whilst preventing disengagement of the tube when in a second position (as shown). <IMAGE>

Description

SPECIFICATION Tube connector This invention concerns a tube connector whereby tubes may easily and reliably be attached one to another.

Flexible tubes or hoses frequently have to be connected to rigid tubes, manifolds or the like, and a variety of methods have been involved, varying from simple pressure deformation of the flexible tube by means of binding with wire, wire or strip clips, for example the well-known worm drive clip of the "Jubilee" type, and push-fits over the rigid tube which may or may not have a lip or other outstanding portion to reduce the risk of slippage, to fairly complex arrangements requiring male and female threaded connectors which co-operate to prevent disconnection or leakage. Such threaded connectors are often found on breathing apparatus, especially of the self-contained subaqua or fire or mines rescue type.

The present invention provides a simple but effective connector which is particularly suitable for the attachment of flexible breathing hoses in breathing apparatus, but also has the possibility of widespread applicability for other uses.

Accordingly, the present invention provides a tube connector comprising a relatively flexible tubular member, a relatively rigid member and a locking member, the tubular member being provided with an abutment section adapted to engage with the relatively rigid member or a part thereof and the locking member being an interference fit with the tubular member, whereby in a first position of the locking member, the tubular member may be easily engaged or disengaged from the relatively rigid member and in a second position of the locking member, the abutment section of the tubular member engages with the relatively rigid member or part thereof and is prevented by the locking member from disengaging therefrom, and the yocking member may be slid axial to the tubular member between said first and second positions.

There are two main embodiments of the present invention, one in which the locking member is external of the tubular member and the other in which the locking member is internal of the tubular member, but in both embodiments, the tubular member is locked or trapped between the locking member and the relatively rigid member.

It is believed that currently all methods of securely attaching a flexible tube to a rigid member, have involved the use of a flexible tube having a plain end, the end being trapped or deformed by the use of a device such as a spring or worm drive clip or by wire wrapping. Although it has been known for grommets to have moulded recesses to correspond to the rigid parts which they fit, grommets are not securely fixed using a locking member. Accordingly, we believe that this invention provides for the first time a simple mechanical interlock between a relatively flexible tubular member and a relatively rigid member.

The relatively rigid member may form part of an apparatus to which a flexible tube is to be joined, such as part of a breathing apparatus, or may be merely a connector element, by means of which other tubes, whether flexible or not, may be joined to the flexible tube. The abutment section of the tubular member may be a recess or may be a flange or lip. It is preferred however, that the abutment section is well defined so that there exists a mechanical interlock with the relatively rigid member or part thereof. That is to say, the abutment section and the corresponding part of the relatively rigid member are preferably provided with edges at right angles to the axis of the tubular member. The relatively rigid member is preferably of a rigid and mechanically strong material (for example metal, a cross-linked plastics or a mechanically strong thermoplastic such as nylon).

The relatively flexible tubular member is conveniently a natural or synthetic elastomer, which term includes reinforced hoses and tubes, or may be a flexible end to a less flexible tube.

The locking member is conveniently a ring capable of being moved by sliding axial to the tubular member to overlie the abutment section of the tubular member and may be provided with a portion by which it may be easily gripped to permit manual movement. Alternatively, it may be desirable that the locking ring is not easily manually moved between the locking position and the disengagement position, to prevent tampering, for safety or other reasons. The locking member may be adopted to be moved only by a special tool or may be shaped or adapted so that a tool such as a screwdriver or other blade or tool is required to initiate movement from the locking position but thereafter can be moved manually.If desired, the locking member may be threaded and engaged a threaded portion on the relatively rigid member or a threaded member attached thereto or mounted therewith, but it is not thought that this is in general necessary since the connector of the invention using a sliding locking member has been found to be safe and secure. For certain uses, however, it may be desirable to increase security of fixing using a screw-on locking member or a locking member in some other way secured to the relatively rigid member. The locking member is suitably substantially rigid, and may be a material such as those listed for the relatively rigid member.

The invention will now be described with reference to the accompanying drawings, in which Fig. 1 is a cross-section of a first connector according to the invention, Fig. 2 is a cross-section of a second connector according to the invention, and Fig. 3 is a cross-section of a third connector according to the invention.

Referring to Fig. 1, the end of a breathing apparatus breathing tube is indicated by 1. The tube has a moulded portion, 2, of reduced internal diameter. A breathing bag and purifier unit (not shown) has attached thereto a brass neck 3, which has an outwardly directed lip, 4, and flange, 5, defining therebetween a recessed portion, 6, into which the moulded portion 2 fits snugly. A brass ring, 7, is slidably positioned on the outside of the breathing tube 1 and is an interference fit therewith, and has an upstanding portion, 8, which serves to be gripped by the fingers of a user.

The ring is slid along the tube so that it overlies the recessed portion 6 (as shown) and is extremely effective in preventing disconnection of the flexible tube from the neck. A small moulded lip, 9, on the end of the tube helps to prevent the ring being lost or dropped when the tube is disengaged for servicing or the like, but is not essential.

Referring now to Fig. 2, an alternative moulded end of the breathing tube is shown. The breathing tube, 11, has a moulded internal recess, 12, into which fits the outstanding lip portion, 14, of neck 13. As in Fig. 1 the lip portion 14 defines, with a flange 15, a recess, 16, in the neck, into which part of the end of the breathing tube fits snugly. A ring, 17, with an upstanding portion 18, to be gripped by the fingers, serves as locking member to overlie and trap the end of the breathing tube in the recess 16.

In the above described embodiments of the inventions, the neck (3 and 13) is of relatively small height above the surrounding metal. This is in marked contrast to conventional connectors in which necks are required of significantly greater height. Particularly in the case of breathing apparatus, there are two unfortunate consequences to this prior design; the metal neck is subject to damage by impact and leverage and also the length of the rigid neck "neutralises" a section of the flexible tube so that either a greater length of breathing tube has to be provided or the wearer has to accept reduced freedom of movement. The present invention offers the opportunity to overcome these disadvantages and at the same time minimises the amount of metal required.

In the embodiment of Fig. 3, a metal canister, 21, has an aperture, 22, which is conveniently circular but need not be so. The canister does not require an upstanding neck as shown in the above two embodiments. A flexible tube, 23, has a moulded circumferential recess, 24, in the end thereof, which fits snugly with the edges of the aperture. A metal locking member, 25, is an interference fit on the inside of the tube 23 and can be simply pushed in to lock the flexible tube onto the edges of the canister.

In all embodiments, it may be found desirable to lubricate the surface of the locking member which contacts the flexible tube. This may be done using a silicone or fluorocarbon grease, or the locking member may have a low-friction coating such as a PTFE coating.

It will be appreciated that a variety of different configurations of co-operating portions of the relatively flexible tubular member and the relatively rigid member, which give the necessary trapping action in combination with a locking member, can be devised without departing from the scope of the present invention. This invention gives a simple and extremely cost-effective connection between a flexible tube and a rigid member, which is reliable and relatively secure.

The simplicity of the connector also means that weight can be saved, which is an important consideration in the case of breathing apparatus.

In addition, connection and disconnection do not necessitate the use of tools and if the locking ring is damaged in use it is a simple matter to replace it.

While the invention has been described with particular reference to breathing apparatus, the connectors may be used also in diverse fields, such as heating or ventilating, in the motor industry etc., and only require a short section of appropriate relatively flexible tube. Thus lengths of rigid pipe may be joined using the connectors of the invention with secure fitting and adequate sealing.

Claims (10)

1. A tube connector comprising a relatively flexible tubular member, a relatively rigid member and a locking member, the tubular member being provided with an abutment section adapted to engage with the relatively rigid member or a part thereof and the locking member being an interference fit with the tubular member, whereby in a first position of the locking member, the tubular member may be easily engaged or disengaged from the relatively rigid member and in a second position of the locking member, the abutment section of the tubular member engages with the relatively rigid member or part thereof and is prevented by the locking member from disengaging therefrom, and the locking member may be slid axial to the tubular member between said first and second positions.

2. A connector according to claim 1, wherein the locking member is external of the tubular member.

3. A connector according to claim 1, wherein the locking member is internal of the tubular member.

4. A connector according to claim 2, wherein the relatively rigid member is or comprises a tubular neck portion which fits inside the tubular member.

5. A connector according to claim 4, wherein the neck portion has a part correspondingly shaped to the abutment section of the tubular member.

6. A connector according to claim 5, wherein the abutment section of the tubular member and the correspondingly shaped part of the neck portion are provided with edges at right angles to the axis of the tubular member.

7. A connector according to claim 3, wherein the relatively rigid member comprises the edges of an aperture into which the tubular member may be fitted.

8. A connector according to any one of the preceding claims, wherein the locking member is generally of ring shape and is capable of being moved to overlie the abutment section of the tubular member.

9. A connector according to claim 8, wherein the locking member has a portion by which it may be easily gripped to permit manual movement.

10. A connector according to claim 1, substantially as hereinbefore described with reference to Fig. 1, 2 or 3 of the accompanying drawings.