Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Patent
1991-06-18
1993-11-02
Yasko, John D.
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
604228, 604218, 128919, A61M 500
Patent
active
052579760
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Field of the Invention
The present invention relates to disposable syringes which are rendered non-reusable after a first injection therewith.
2. Background and Prior Art
Syringes disposable after a single use are being used more and more to avoid the risks of contamination from using a syringe poorly sterilized after a first use.
However, contaminations are due to the use by drug-addicts of previously used syringes which are not sterilized or poorly sterilized.
In order to avoid such accidents, syringes have been proposed which are rendered automatically non-usable after a first injection.
U.S. Pat. No. 3 934 586 (Easton et al) describes pre-filled syringes which make it possible to inject several successive doses.
The operating rod of these syringes bears stops which abut one another on the end of the barrel and which are broken along an oblique line of maximum weakness which leaves a sharp edge which scores the wall of the barrel. Such syringes cannot be re-used.
Patent De-A-1 965 761, FR-A-2 027 681, U.S. Pat. No. 3 667 657 (Chiquiar-Arias) describe pre-filled syringes which comprise a small knife which is fixed laterally on the operating rod and which is engaged in an opening in the cylindrical barrel. These syringes cannot be sold empty to be filled by the user as, as soon as the piston is driven into the barrel, the knife cuts the latter.
U.S. Pat. No. 3 951 146, DE-A-2 354 628, FR-A-2 204 429 (Chiquiar-Arias) describes syringes in which the operating rod bears a casing or a notch in which is housed a small knife which is pushed radially by a spring and which presents a rounded rear edge and a cutting front edge. It is possible to withdraw the piston rearwardly in order to suck liquid into the barrel without scratching the wall of the barrel. In order to drive the piston to the bottom of the barrel, a protection sheet is engaged between the wall of the cylindrical barrel and the cutting blade which is removed thereafter.
The problem to be solved is to provide self-destroying syringes which may be sold empty and which make it possible firstly to drive the piston in the barrel in order to drive out the air without scratching the barrel, then to withdraw the piston rearwardly in order to suck in a liquid without scratching or cutting the wall of the barrel, then to drive the piston again into the barrel in order to inject the dose of liquid contained therein, while cutting or scratching or breaking the wall of the barrel in order to render the syringe unusable a second time.
SUMMARY OF THE INVENTION
A syringe according to the invention comprises a cylindrical barrel, a piston displaceable inside said barrel, a rod for moving said piston and a cutting member which scratches or cuts or breaks the wall of said barrel during the injection of the liquid contained in said barrel.
The solution of the aforesaid problem consists in a syringe in which one end of the rod and said piston are connected by means which allow a relative axial displacement and either the rod or piston bears at least one flexible finger, which bears at its free end a cutting member, whilst the other bears a deviation means which cooperates with said flexible finger to deform the latter by pushing said cutting member outwardly when said end of the rod and said piston approach one another, with the result that, when the rod is withdrawn rearwardly in order to fill the syringe with the liquid to be injected, said flexible fingers occupy a position in which said cutting members are retracted inside said barrel and do not touch the wall thereof and when said piston is driven into said barrel, pushing on the rod to inject the liquid, said flexible fingers move apart and said cutting members are pushed outwardly and cut or scratch the wall of the barrel, which renders the syringe unusable a second time.
According to a first embodiment, said piston or one end of the rod bears one or more ramps inclined with respect to the axis of the syringe against which said flexible fingers slide, moving apart towards the outside when the
REFERENCES:
patent: 3934586 (1976-01-01), Easton et al.
patent: 3951146 (1976-04-01), Chiquiar-Arias
patent: 4731068 (1988-03-01), Hesse
patent: 4961728 (1990-10-01), Kosinski
patent: 4979943 (1990-12-01), Trenner
patent: 5037393 (1991-08-01), Ellgass
patent: 5084017 (1992-01-01), Maffetone
patent: 5085640 (1992-02-01), Gibbs
patent: 5149323 (1992-09-01), Colonna
Polutta Mark O.
Yasko John D.
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