Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Patent
1996-05-03
1997-12-09
Jackson, Gary
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
604192, A61M 500
Patent
active
056954760
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to needle protection assemblies of the kind including a channel-shape protector housing having a slot opening along a major part of the length of the housing, a needle assembly slidable along the housing between a first position in which a tip of a needle is located within the housing and a second position in which the tip of the needle is exposed at one end of the housing and a cannula assembly mounted on the needle assembly such that it can be slid off the tip of the needle in the second position.
The invention is more particularly concerned with needle protection assemblies for intravenous cannula insertion devices, or the like.
BACKGROUND ART
Intravenous cannula insertion devices of the over-the-needle kind comprise a needle with a bevelled tip that projects by a short distance from the forward, patient end of an intravenous cannula. The cannula is inserted by pushing the needle tip into a vein, then sliding the cannula forwardly off the tip of the needle, into the vein, and withdrawing the needle from the rear end of the cannula. An example of such a device, including a tubular protector surrounding the device before use, is described in EP-A-0054671. The protector has a longitudinal slot along which the cannula hub is slid on insertion. After use, the needle is withdrawn into the protector, leaving the cannula in the vein. The protector provides protection from needle-stick injury before and after use. It is common practice, however, for some clinicians to bend the needle before use in order to give a preferred shape for introduction. In such a case, the tip of the needle can protrude from the slot of the protector when it is withdrawn after use. This can provide a hazard to the user.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide an improved needle protection assembly.
According to the present invention there is provided a needle protection assembly of the above-specified kind, characterised in that the assembly includes a guard mounted on the needle assembly such that it is displaced forwardly to the one end of the housing when the needle assembly is slid to the second position, and a lock for retaining the guard at the one end of the housing when the needle assembly is retracted rearwardly to the first position, and that the guard covers the slot in the housing in the region of the tip of the needle when the needle assembly is retracted to the first position.
The lock preferably comprises a reslient catch on the guard and a locking surface on the housing. The resilient catch may be a rearwardly-extending inclined tab. The needle protection assembly preferably includes a second lock for locking the needle assembly in the first position after it has been retracted into the first position. The second lock may be provided by a forwardly-extending inclined tab on the needle assembly and a rearwardly-facing locking surface on the housing. When the guard is in the first position, the tab on the needle assembly may engage an upper surface of the tab on the guard so that when the needle assembly is slid forwardly, the tab on the guard deflects the tab on the needle assembly over the rearwardly-facing locking surface.
The guard preferably has a surface formation on an upper surface, the needle assembly having a surface formation at one end of an arm, the arm extending from a catch resiliently-mounted on the needle assembly, the needle assembly being displaced from the first to the second position by engaging one surface of the catch so that its arm is urged downwardly, and the needle assembly being displaced from the second to the first position by engaging another surface of the catch so that its arm is urged upwardly and the surface formation on the arm clears the surface formation on the guard. The guard may have a lateral plate with a non-circular aperture, the cannula assembly extending through the aperture and the rear end of the cannula assembly being shaped such that it can only pass through the aperture when oriented cor
REFERENCES:
patent: 4957488 (1990-09-01), Cameron et al.
patent: 4994040 (1991-02-01), Cameron et al.
patent: 5395347 (1995-03-01), Blecher et al.
patent: 5425721 (1995-06-01), Malenchek
patent: 5496274 (1996-03-01), Graves et al.
patent: 5498244 (1996-03-01), Eck
patent: 5582597 (1996-12-01), Brimhall et al.
patent: 5584818 (1996-12-01), Morrison
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