Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-04-02
2001-07-31
Mendez, Manuel (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S905000
Reexamination Certificate
active
06267754
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is concerned with medical catheters and cannulae, and in particular is concerned with a coupling device for connecting a cannula or catheter to a connection tube through which liquid to be administered to a patient is delivered or fluid to be taken from a patient is collected.
2. The Prior Art
A form of coupling which has been in widespread use for many years comprises a female member fixed to the catheter end and having a moulded plastic hub defining an inwardly tapering frustoconical socket, and a male member which is fitted to the end of a connection tube forming part of an administration set for example, and which includes a tapering frustoconical spigot of complementary form to the hub socket for engaging therein with a friction fit. The coupling is made by pushing the male and female members together and is disconnected by pulling them apart. In order to help prevent unintentional disconnection it is known to equip the male member with an internally threaded cap which can be screwed onto a flange provided at the free end of the hub of the female member.
In WO 95/22369 there are described several improvements to medical cannulae couplings aimed at overcoming drawbacks inherent in the known coupling described above, especially regarding the dangers of air embolism should the coupling become unintentionally disconnected, and infection due to bacterial colonisation of the coupling. With the same basic objectives in mind the present invention is concerned with further improvements to medical cannulae couplings.
SUMMARY OF THE INVENTION
In accordance with one aspect the invention there is provided a coupling for a medical cannula or the like including a female member having a socket, a male member having a spigot engagable with a push fit into the socket, a cap attached to one member and rotationally engagable with the other member to secure the spigot against disengagement from the socket, and a locking arrangement to lock the cap against rotation in the direction of disengagement from the other member, characterised in that the locking arrangement includes a sleeve provided on the cap and a slide movable on the other member to engage the sleeve and thereby lock the sleeve and cap against rotation in the disengagement direction.
The coupling of the invention includes a novel system for locking the male and female members against accidental separation. Conveniently, the cap is provided on the male member and has a splined sleeve, and an axially movable slide on the female member is arranged to be engageable with the sleeve to lock the sleeve, and hence the cap, against rotation relative to, the hub of the female member.
Conveniently, the sleeve is internally splined and the slide includes a collar with external splines of complementary configuration and arrangement to the sleeve splines. To facilitate locking engagement of the collar with the sleeve after the cap has been tightened to secure the hub and spigot connection, the collar is preferably capable of limited rotational movement. e.g. through 10°-15°, to enable alignment between the splines of the sleeve and collar. The ends of the splines of the collar and/or sleeve can be shaped to guide the splines of the two parts into correct rotational alignment as the collar is moved from an unlocked to a locked position.
In an especially expedient embodiment, the cap is locked against rotation in a direction to release the coupling by a valve actuator of the female member. The female part of the coupling includes a valve for closing the connection between the hub socket and the cannula tube, e.g., when there is no male part fitted to the socket. The valve conveniently comprises a tube section with a flexible wall enabling the tube to be collapsed by a pinching action to close the passageway through the tube. An element, such as a ball, for pressing on the tube can be actuated by a slider on the female coupling member. This slider, in the preferred construction, carries the splined collar which interlocks with the sleeve fast with the cap.
In accordance with a further aspect of the invention provides a medical coupling in which the male and female members have finger gripping sections at which the members may be held to bring the spigot and hub together and to rotationally engage the securing cap with the hub. The gripping sections being axially spaced from the hub and cap, and a casing is provided to define a sealed housing around the coupled parts of the male and female members with the gripping sections remaining outside the housing.
By this construction an hermetically sealed enclosure can be formed around the parts with which fluids being administered to a patient may come into contact, and as the only parts which need to be handled are located outside the sealed enclosure, the risk of the enclosed parts becoming contaminated, such as by bacteria which can colonise on the surfaces, is significantly reduced.
In case where there is a locking device, such as the splined collar described above, this device can be located on the female member so as to be housed within the casing when it is fitted to the coupling. Furthermore, the interior of the casing can be so configured that it can only be closed around the coupling if the locking collar is in its correct locking position. This means that where the locking collar is fixed to the valve actuator, the casing can be arranged so that it can not be successfully applied with the valve in a closed condition. So that the locking collar and/or valve actuator can be adjusted without need to be touched with the hand, a tool, conveniently a two pronged fork, can be provided in a sterile pack with the casing and possibly the male and/or female coupling members. The tool may serve a dual purpose in being adapted to open the sealed casing when it is desired to access the connection between the male and female members, e.g., to connect a fresh administration set.
A more complete understanding of the invention will be gained from the following more detailed description in which reference is made to the accompanying drawings, wherein:
REFERENCES:
patent: 4340052 (1982-07-01), Dennehey et al.
patent: 4405312 (1983-09-01), Gross et al.
patent: 4473369 (1984-09-01), Lueders et al.
patent: 5037405 (1991-08-01), Crosby
patent: 5531695 (1996-07-01), Swisher
patent: 5545152 (1996-08-01), Funderburk et al.
Gossett PLLC Dykema
Mendez Manuel
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