Conventionally, connectors for connecting an endotracheal tube to an anaesthetic circuit have consisted of a hollow cylindrical tapered insertable portion for inserting into the flexible endotracheal tube and a cylindrical circuit-side portion, generally a standard 15 mm tapered male adaptor, for connecting to the anaesthetic circuit. When such a prior art connector is connected to an over-rigid tube, particularly when temperatures affect the flexibility of the material of the tube, there is a tendency for such prior art connectors to become accidentally disconnected. Also, in cases where such a prior art connector is inserted too tightly into the tube, the withdrawal of the connector from the tube, frequently carried out in order to facilitate new techniques being employed by the profession, often proves impossible without the tube being accidentally dislocated from the trachea of the patient.

Moreover, in order to achieve a reliable connection between the endotracheal tube and the anaesthetic circuit, improvised additional fixing means, such as surgical tape, are often employed.

It is an object of the present invention to provide a connector which may be easily inserted into a flexible tube, is secure when inserted, and may be easily withdrawn when required.

According to the present invention there is provided a tracheal tube connector, comprising a hollow cylinder, with an insertable portion of substantially constant diameter for connecting to a flexible tube, a finger grip portion, and a circuit side portion, the insertable portion having sealing means and an external coarse thread with a sloping leading edge profile such that, in use, the connector may be easily pushed into the tube to form a seal on the insertable portion, but is removable by a screwing action.

The thread of the insertable portion of the connector may comprise a sloping leading edge and a trailing edge at substantially 90" to the base of the thread.

The thread of the insertable portion of the connnector may alternatively comprise a convex leading edge and a trailing edge at substantially 90" to the base of the thread.

Still alternatively, the thread of the insertable portion of the connector may comprise a convex leading edge and a concave trailing edge, being broader at the base of the thread than at the top.

Again alternatively, the thread of the insertable portion of the connector may comprise a concave leading edge and a trailing edge at substantially 90" to the base of the thread.

Preferably, the insertable portion is cylindrical in shape with its free end tapered in order to facilitate easy insertion into the tube.

Also preferably, the insertable portion is provided with the sealing means located between the free end of the insertable portion of the connector and the beginning of the thread, to provide an air-tight seal, in use.

Advantageously, the finger-grip portion is located between the insertable portion and the circuit-side portion and is shaped to provide a grip on the connector.

In order to aid in understanding the invention some specific embodiments thereof will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a partially sectioned side view showing a connector according to the invention, with a cross-section through the thread; Figure 2 is a cross-section showing the connector of Figure 1 inserted into a section of tubing; Figure 3a shows a profile of the preferred thread of the connector of Figure 1; Figures 3b to 3d show profiles of alternative threads.

Referring to the drawings, there is shown a connector 1, with a circuit-side portion 2 conventionally designed to connect to an anaesthetic circuit, an insertable portion 4 for connecting to an endotracheal tube 8, and a cylindrical finger-grip portion 3 which is grooved to provide grip when inserting or removing the connector 1 and has a greater diameter than that of the circuit-side portion 2 or the insertable portion 4. The insertable portion 4 has a tapered end 5 to facilitate easy insertion of the connector 1 into the tube 8, a sealing ring 6, in the form of a ring- like ridge, which provides an air-tight seal between the connector 1 and the tube, and a thread 7 in the form of a male helical ridge on the external surface of the insertable portion 4. The sealing ring 6 is located on the insertable portion 4, preferably between the tapered end 5, and the thread 7. Alternatively, the sealing ring 6 may, in the same location, be provided by an OS ring, sunk into a circumferential groove purposely formed in the cylindrical wall of the connector 1.

Referring in particular to Figure 2, the insertable portion 4 of the connector 1 is inserted into a tube 8, tapered end 5 first, so that the finger-grip portion 3 defines the optimal distance the insertable portion 4 can travel down the tube 8. As the insertable portion 4 of the connector 1 is inserted into the tube 8, the sealing ring 6 and the thread 7 engage with the inner surface of the tube 8.

Referring to Figures 3a to 3d, these show possible variations of the profile of the thread 7 to ensure that the connector 1 may be easily pushed into the tube 8, that a secure connection is formed between the insertable portion 4 and the tube 8, and also that the connector 1 will, by rotation in a screw-like action, be easily removable when required. Figure 3a shows a preferred embodiment of the thread 7, with a broad base 11 on the insertable portion 4 of the connector 1, with a sloping leading edge 9 and a trailing edge 10 at substantially 90" to the base 11. Figure 3b shows a variation on Figure 3a, with a convex leading edge 9 and a trailing edge 10 at substantially 90" to the base 11. Figure 3c shows another variation of the form of the thread 7, with a convex leading edge 9 and a concave trailing edge 10. Figure 3d shows a further variation, wherein the leading edge 9 is concave and the trailing edge 10 is at substantially 90" to the base 11. It will be obvious to one skilled in the art that further variations of profile of the thread 7 may be possible. It is advantageous that the outermost part of the thread, which comes into contact with the tube 8, be blunt in profile, to prevent damage to the inner surface of the tube 8.

In use, the connector 1 is inserted into an endotracheal tube 8, with the tapered end 5 and the sealing ring 6 entering first. The connector 1 is inserted into the tube 8 by pushing the insertable portion 4 directly into the tube 8 in one direction, this insertion being facilitated by the curvature of the leading edge 9 of the thread 7. However, the profile of the thread is designed both to prevent accidental dislodgement of the connector 1 from the tube 8, and to facilitate, when required, its easy and controlled withdrawal from the said tube 8. The easy and controlled withdrawal of the connector 1 is achieved by its rotation anti-clockwise in a screw-like action.

Rotation causes the connector 1 to travel up effortlessly in the track of its own thread 7, thus creating minimum disturbance to the tube 8.

It will be understood that various alterations and modifications may be made to the above embodiments without departing from the scope of the invention, and that the invention is applicable to facilitate connections between other forms both of flexible tubing and adaptors. For instance, the finger-grip of the connector may also be square, triangular, oblong or hexagonal or in fact any shape which provides a suitable grip on the connector.