GB2192438A - Coupling device for anaesthesia and respiration appliances - Google Patents

Abstract

For the establishment of a reliable and at the same time quickly detachable connection between the tubes (8) and the pipe sockets (4,5) on the parts (1) of an anaesthesia or respiration appliance, the tubes (8) are provided on their inside with a flexible lip (9) which engages in an undercut (9) on the pipe socket (4,5) when the tube is pushed on. This undercut (7) may be formed in particular by a shoulder at the end of a cone such as that which the ISO specifies is to be attached to the pipe sockets of the parts of anaesthesia and respiration appliances. <IMAGE>

Description

SPECIFICATION Coupling device for anaesthesia and respiration appliances The invention relates to a coupling deviceforthe establishment of a secure and at the same time quickly detachable connection between the tubes and the pipe sockets on the parts of an anaesthesia or respiration appliance, in which the pipe socket is provided with an undercut disposed at a distance from its end and the tube is provided with a flexible catch element engaging in the undercut.

Anaesthesia and respiration appliances comprise a number of parts which are interconnected bytubes which serve to carry the respiratory air or else to supply anaesthetics and remove mucous and the like by suction. As one of the things on which the life of a patient depends is the troublefree operation of the anaesthesia or respiration appliance, it must be ensured that the tubes connecting the parts ofthe appliance do not become detached during operation from the pipe sockets onto which they are pushed.

On the other hand, it may be necessary in emergency situations to detach the tube connections extremely quickly. The pipe sockets with standard cone which are fitted on anaesthesia and respiration appliances and connectors nowadays and onto which thetubes usually consisting offlexible latex are pushed do not meet this requirement because they entail the risk that the tubes may inadvertently slip off the pipe sockets and thus cause accidents. In this context "tubes" are also to be understood asthetube-like attachments to parts of the appliance which are intended for pushing onto pipe sockets, such as for example the attachment to respiratory bags and the like.

Various embodiments of the coupling devices which meet the requirementfora reliable and at the same time quickly detachable connection are already known. These coupling devices take the form of special systems with parts which can be firmly fixed to the end of the tube and have a mechanis#m with varying degrees of complexity, by which it is possible to establish a catch connection with the pipe sockets which ensures a reliable connection to the pipe socket under the forces normally occurring in operation but can be detached very quickly with an increased application of force. Although these systems ensure satisfactory operation, they are very expensive and, due to their complicated mechanism, take on such dimensions that, if put into application, already existing accessories of the anaesthesia appliances can no longer be used.

In contrast, the invention is based on the object of creating a coupling device ofthetype mentioned at the start which meets the requirements for establishment of a reliable and at the same time quickly detachable connection but can be produced less expensively than the previously known systems and the application of which does not constitute an obstacle to the continued use of the existing accessories of such appliances.

According to the invention, this object is achieved in that the catch element is formed by a flexible lip provided on the inside of the tube.

Thus, according to the invention no use is made of any expensive additional system to establish a stable connection between the tubes and the pipe sockets of the parts of theanaethesia or respiration appliance, instead a flexible lip is provided in a simple way on the inside of the tube, which lip ensures the desired reliable connection between tube and pipe socket when it engages behind the undercut on the pipe socket but whose form closure with the undercut on the pipe socket can be overcome with increased application offorceto make it possible to detach the existing connection quickly when required. The design of lip and undercut allows for the force which is necessary for separation of the connection to be adjusted to the desired value with accounttaken of the flexible properties ofthetube material and ofthetube diameter.Thus, the invention provides a very simple way of solving a long-standing problem with very little outlay. This solution also has the particular advantage that no modifications need to be made to existing devices in particular in cases where they are provided with ISO standard cones which form a shoulder on their rim facing away from the pipe end, which shoulder can be readily used as the undercut with which the lip provided on the tube interacts.

In a preferred embodiment of the invention, the lip is directly moulded onto the inside ofthe tube. It may then beformed during the productionof the tube by having a corresponding design ofthe mould used for this purpose, withoutthis giving rise to any additional costs. At the same time, a lip designed as an integral part of the tube offers maximum operational reliability.

There is of course also the possibility of providing the lip on a special partconnectedtothetube.

Consequently, another advantageous embodiment of the invention envisages that the lip is provided on an annular body, preferably consisting of plastic, inserted in the widened end ofthetubeandfirmly connected to the tube. In this embodiment of the invention too the connection between the annular bodyandthetube end can makethe lip into an.

inseparable part of the tube. In this case, there is no difficulty in finding for the annular body materials, and in particular plastics, which both have the desired flexibility properties and can be connected well to the material of the tube and in addition can be sterilized without any problems just like the tube.

The avoidance of complicated systems by the application of a simple flexible lip is of considerable significance in general for the problem of sterilization of the individual parts of anaesthesia and respiration appliances.

As already mentioned, a special advantage ofthe invention consists in that the lip provided on the tube, according to the invention, can interact directly with the shoulder which is located on the end of ISO standard cones, such as are frequently fitted on the pipe sockets of parts of anaesthesia and respiration appliances.But even cases where undercutsshould be provided on such pipe sockets for interaction with a lip existing in the tube, it is expedient if the undercut forms a shoulder perpendicular to the axis of the pipe socket on its rim facingzthe end of the pipe socket, because such a shoulder forms a perfect contactsurfaceforthe rim ofthe lip, butwithout having a barb-like effect which prevents the desired separation of the tube from the pipe socket even under increased.application of force.

On the other hand, it is advantageous.iftheflexible lip provided on the tube has a sharp edge by which it comes into engagement with the undercut to ensure reliable blocking. Itshould be taken into-account in particular here that, with the small wall thicknesses of customary pipe sockets, it is not possible to make deep undercuts. Consequently, for example the shoulder at the rear end of an ISO standard cone has a a radial extent of only-approximately 0.8 mm. A radial extent of such a shoulder exceeding 1 mm would probably not readily be feasible in practice.

Therefore, a preferred embodimentoftheinvention envisages thatthe lip has, seen from the end ofthe tube, a first conical surface constricting the tu'be and is limited at its inner end by a second conical surface which has an apex angle which is in the same direction butgreaterthan that ofafirst conical surface. This gives the lip a sawtooth-like contour, which ensures the desired reliability even with small dimensions. In this case, a radial flank at the end of thalipwould haveto beconsideredasa limiting case of the second conical surface.

If the lip is provided on an annular body inserted into the end ofthetube, this body usually consists ofa stiffer material than the elastomerictube.

Therefore, it is expedient if, for adjusting the desired retaining force of the lip, the second conical surface has substantiallythe same axial extent as the first conical surface and lies opposite and at a distance from a conical surface which is formed by the inner tube wall and connects the widened end ofthetube to section of constant diameter.

The explanation of the invention up to now has assumed thatthe lip is on the inside ofthe tube and the undercut is on the periphery ofthe pipe socket, becauseinthiswayusecan be made ofthe shoulders on the pipe sockets ofknown appliance parts. However, itgoes without saying that, in the case of newly designed appliances, the desired reliable and at the same time quickly detachable connection, under corresponding applicational force, between tube-and pipe socket, can be established in the converse way if a lip is located on the periphery of a pipe socket and interacts with an undercut provided inside the tube.

The invention will be described in more detail and explained belowwith reference to the exem#plary embodiments represented in the drawing. The features to be taken from the description and the drawing can be used individually in themselves or together in any combination in other embodiments ofthe invention. In the drawing, Figure l shows the view of a coupling device according to the invention on a pipe socket of an #appliance part represented in side view and of a tube, represented in section, pushed onto the pipe socket Figure 2 shows a longitudinal section through the end of the tube represented in. Figure 1, and Figure3 shows a section through a further embodiment of a tube which can be used in connection with the appliance part according to Figure 1.

Figure 1 shows an m connector 1, which is conventionally used with anaesthesia and respiration appliances and has, apart from a closable suction removal socket 2 and a connection Bfor anaesthesia or respiration inhalers and endotracheal tubes, two pipe sockets 4 and 5 which are intended fortheconnection of respiratory tubes and each have attheir ends an ISO standard cone 6, which ends in a shoulder 7 at a certain distance from the end ofthe pipe socket. With an external nominal diameter of 22 mm, the shoulder7 has a radial extent of approximately 0.8 mm.It must be ensured that, although they execute periodic movements in time with the respiratory equipment, the respiratory tubes pushed onto the pipe sockets 4, 5, such as the respiratory tube 8 pushed onto the pipe socket 5, do not slip off the pipe sockets 4, 5 and thereby interrupt the breathing of the patient and possibly endanger his life. On the other hand, there must be the possibility of quickly pulling offthe tubes from the pipe sockets 4, 5 in-an emergency. Similar conditions also apply to other tube connections on anaesthesia and respiration appliances, although in general it should be sufficient if there is an easily accessible point at which the respiratory tubes on the pipe sockets of a part of the appliance can be pulled off.

The end of the tube 8 pushed onto the pipe socket 5 of the connection 1 according to Figure 1 is represented separately in Figure 2. As canbe seen, this tube 8 has on its inside a flexible lip 9 which is moulded onto the inside of the tube 8, in otherwords is an integral partofthe latter. It is limited byafirst conical surface 10, which beg ins just behind the end 11 of the tube 8 and hastheeffectuptotheendofthe lip 9-of constricting the innertube diameter. At its inner end, the lip 9 is limited by a second conical surface 12, which opens on the same side as the conical surface 10, but whose apex angle is greater than the apex angle o-ofthe first conical surface 10.In this way, the lip 9 is given a sawtooth-like profile in cross-section, with a claw-liketip 13, which comes to rest firmly against the shoulder 7 of the pipe socket forming an undercut, when the tube is fitted on the pipe socket 5.

A pulling off of the tube is consequently only possible if the flexible lip 9 is widened radially to such an extentthat it can slip overtheshoulder7 on the pipe socket 5, in otherwords can slip out ofthe undercut formed by the shoulder 7. The force necessaryforthis can be adjusted by dimensioning the lip 9 such that an independent slipping off ofthe tube from the pipe socket is reliably avoided, but this force can be readily applied whenever it is necessary to pull the tube off the pipe socket in an emergency.

Therefore, this extremely simple arrangement meets the condition of establishing a connection between the tubes and the pipe sockets on the parts of an anaesthesia or respiration appliance which connection on the one hand ensures absolutely reliable operation and on the other hand is quickly detachable nevertheless in an emergency.

Figure3showsanembodimentofatube 18in which the lip 19 is not moulded onto the inside ofthe tube but is located on an annular body 31 of thermoplastic material, inserted in the end ofthe tube 18. This annular body 31 has a first cylindrical section which is inserted in a corresponding cylindrical section 21 on the end ofthetube 18 and is undetachablyconnected here to the tube. For example, the annular plastic body 31 may be glued into the tube end 21. The internal diameter ofthe annular plastic body 31 is substantially the same as the diameter of the tube 18, so that the section 21 of the tube is widened corresponding to the external diameter of the annular body 31.

The lip 19 provided ontheannular body 31 is also limited bytwo conical surfaces 20 and 22, which both have apex angles a', (3'which are in the same direction but of which the apex angle ss' ofthe outer conical surface 22 is only slightly greater than the apex angle ' of the inner conical surface 20.

Furthermore, the two conical surfaces 20, 21 in this case have substantially the same axial extent 1, so that a very narrow and axially extensive lip is produced. This lip is opposite and at a distance from a conical surface 24, which connects the widened head 21 of the tube 18 to its section of constant diameter.

Here too, it is again ensured that the sharp edge 23 at the end of the lip 19 catches in the undercut formed by the shoulder 7 on one of the pipe sockets 4, Swhen such atube is pushed onto such a pipe socket. The in this caseverythin lip in turn ensures that, despite the use of a plastic, which although flexible is not elastomeric, the catch between lip 19 and shoulder7 can be detachedwith reasonable application of force whenever it is necessary to pull the tube quickly off the pipe socket.At the same time, here too it is again ensured that the force necessary for pulling offthetube 18from a pipe socket 4 or 5 is great enough to prevent reliably any independent detachment ofthetubefrom the pipe socket.

Itgoeswithoutsayingthattheinvention is not restricted to the exemplary embodiments represented butthat deviations from them are possible without going beyond the scope of the invention. In particular, the lips provided on the tube end may interactwith undercuts provided especially for this purpose on the pipe sockets and it is also possible to use a large number of different, matched cross-sectional shapes of lips and undercuts. To this extent, the term "lip" is intended to designate annular collars of any cross-section. It further goes without saying thatthe invention can also be realised in the form of its kinematic reverse, in otherwords lips, collars or beads provided on the periphery of pipe sockets may interact with corresponding undercuts formed on the inside of the tube by annular grooves, steps and the like. Finally, the tubes to be fastened on the pipe socket need not be independent structures ofsizeable length but may also be elastomeric attachments to appliance parts serving for the purposes of connection and fastening, such as for example the attachments of respiratory bags.

Claims (7)

1. Coupling device for the establishment of a reliable and atthe same time quickly detachable connection between the tubes and the pipe connections on the parts of an anaesthesia or respiration appliance, in which the pipe socket is provided with an undercut disposed at a distance from its end and the tube is provided with a flexible catch element engaging in the undercut, characterized in that the catch element is formed by a flexible lip (9, 19) provided on the inside ofthetube (8,18).

2. Coupling device according to Claim 1, characterized in thatthe lip (9) is moulded onto the inside of the tube (8).

3. Coupling device according to Claim 1, characterized in thatthe lip (19) is provided on an annular body (31), preferably consisting of plastic, inserted in the widened end (21 ) of the tube (18) and firmly connected to the tube (18).

4. Coupling device according to one ofthe preceding claims, characterized in that the undercut forms a shoulder (7) perpendicularto the axis ofthe pipe socket on its rim facing the end of the pipe socket (4,5).

5. Coupling device according to one of the preceding claims, characterized in that the lip (9, 19) has, seen from the end of the tube (8,18), a first conical surface 20) constricting the tube and is limited at its inner end by a second conical surface (12, 22) which has an apex angle ((3, ss') which is in the same direction but greater than that ofthefirst conical surface 20).

6. Coupling device according to Claims 3 and 5, characterized in that the second conical surface (22) of the lip (19) has substantially the same axial extent (1 ) as the first conical surface (20) and lies opposite and at a distance from a conical surface (24) which is formed bytheinnertubewall and connects the widened end (21 of the tube (18) to its section of constant diameter.

7. Either of the coupling devices substantially as herein described with reference to the accompanying drawing.