Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Patent
1996-08-22
1999-10-19
Stright, Jr., Ronald K.
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
604192, 604240, 604199, 206365, A61M 500, B65D 8310
Patent
active
059680210
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to needle units for disposable injection needles, and specifically a needle unit comprising a needle mounted in a hub having a sleeve made from a plastic material and surrounding an end of the needle in a distance from that needle, the unit being designed to be mounted at the outlet end of a syringe having a cylindric connecting piece with a recess in a plane perpendicular to the cylinder axis, which connecting piece is received in the sleeve of the needle unit.
DESCRIPTION OF RELATED ART
By known needle units an inner surface of the depending sleeve is provided with an inner thread corresponding to an outer thread on the connecting piece of the syringe which the unit is intended for. The unit may then be mounted on the syringe simply by screwing it onto the connecting piece of the syringe.
However, such a screwing may be difficult to perform especially to people with reduced tactile motor function, and particularly unscrewing of a used unprotected sharp needle may be difficult if the screw connection has been carefully tightened when the unit was mounted.
Needle units are known of a type which can without screwing be mounted on a syringe which instead of a thread has a circumferential recess at the inner end of its connecting piece. Such needle units have at the inner side of their depending sleeves protrusions engaging the recess of the receiving connecting piece of the syringe. This construction is known from disposable syringes formed by snapping a needle unit onto the neck end of a cylinder ampoule, whereafter the syringe with the needle unit mounted is disposed of after use as a unity, as the needle unit cannot easily be demounted.
SUMMARY OF THE INVENTION
The object of the invention is to provide a needle unit of the snap-on type, which may easily be snapped onto a durable pen type syringe and which may easily be dismounted from the syringe to make it possible to change the needle without having to dispose of the syringe.
This is obtained by a needle unit of the above mentioned type, which unit is characterized in that the sleeve is so designed that the locking engagement between the protrusions of this sleeve and the recesses of the connecting piece is released when radial inward pressures are exerted on specific zones of the sleeve.
In an embodiment of the needle hub at least two protrusions may be provided on the inner surface of the sleeve, the apexes of these protrusions lying on a circle having its centre in the axis of the needle unit and having when the sleeve is not deformed a radius which is smaller than the radius of the connecting piece, and the connecting piece may fit into the sleeve with a play allowing deformation of the sleeve to an extent enlarging the radius of the circle through the apexes of the protrusions to be at least equal to the radius of the connecting piece.
The sleeve may either be deformed when the connecting piece is pressed into the sleeve urging the protrusions to pass over the side wall of this connecting piece until they snap into the recesses in this wall, or the deformation may be obtained by applying a radial inward pressures on the outer side of the sleeve at zones circumferentially displaced from the position of the protrusions. By such radial pressures the sleeve will be deformed so that the protrusions will be drawn out of the recesses in the connecting piece.
To prevent the sleeve from wriggling on the connecting piece due to the play between this sleeve and connecting piece, longitudinal spacer ribs may be provided on the inner surface of the sleeve at positions lying between the protrusions and zones lying halfway between the protrusions, which zones are designed for application of radial inward pressures.
Such spacer ribs are especially indispensable when according to the invention only two protrusions are provided diametrically opposite each other.
In another appropriate embodiment of the invention three protrusions are provided 120.degree. circumferentially spaced. To dismount this needle unit a
REFERENCES:
patent: 3989044 (1976-11-01), Meierhoefer
patent: 4772272 (1988-09-01), McFarland
patent: 4840272 (1989-06-01), Goldman
patent: 4961730 (1990-10-01), Poncy
patent: 4968304 (1990-11-01), Alter et al.
patent: 5226894 (1993-07-01), Haber et al.
patent: 5312370 (1994-05-01), Talonn et al.
Novo Nordisk A S
Stright Jr. Ronald K.
Zelson Esq. Steve T.
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