Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2000-05-09
2001-03-27
Yasko, John D. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S195000
Reexamination Certificate
active
06206853
ABSTRACT:
The present invention concerns a syringe with a self-retracting needle.
It also concerns a circlip for preventing relative movement in translation of two bodies sliding one within the other.
Medical syringes are used to inject a substance, generally medication, into the body of a patient using a hollow needle.
So-called single-use syringes are now in general use, and are sold in a sterile condition in sealed packaging. The intention is that they should not be reused, with the aim of preventing any risk of accidental contamination of one patient by another. However, this widely used equipment does not protect medical personnel from accidental pricking and does not materially prevent reuse of the syringe if the user does not intentionally destroy it after use.
Document PCT/FR90/00572 describes a syringe with a self-retracting needle, comprising a body carrying injection-needle support means at one end, a piston mobile in said body, a sheath in which the body can slide, and a spring disposed between the sheath and the body. At least one first flexible lug is also provided, carried by the sheath and cooperating in abutment fashion with a first shoulder to define a first position of immobilization of the body relative to the sheath in a first direction, the spring being compressed and the needle being deployed from the sheath in this first position, and with a second shoulder to define a second position of immobilization in the same direction, the spring being at least partly relaxed and the needle being inside the sheath in this second position. The change from the first position to the second position is effected by cooperation of the piston with the flexible lug to release the lug from the first shoulder at the end of the travel of the piston and thereby, due to the effect of the spring, cause the body to be withdrawn into the sheath until it is immobilized in the second position.
The above syringe has at least one second flexible lug and at least one third shoulder, in respective opposite directions to the first flexible lug and to the two first shoulders, respectively on the sheath and on the wall of the body to immobilize the body in the sheath when it is in the second immobilizing position, in the direction opposite to the first direction.
However, the type of syringe well known in the art has the drawback that its flexible lugs can easily be broken when the user attempts to return the body to its first immobilizing position in the sheath with the aim of using the syringe again.
The flexible immobilizing lugs therefore do not guarantee single use of the syringe.
Document FR 2 680 110 describes a syringe having a body that can slide inside a sheath and is prevented from sliding inside the sheath by a circlip which lodges in two grooves which are aligned in the immobilizing position, one of the grooves being formed on the outside wall of the body of the syringe and the other groove being formed on the inside wall of the sheath.
This immobilizing system is complicated to manufacture because it requires grooves on the inside of the sheath and on the outside of the syringe body.
The object of the present invention is to propose a single-use syringe with a self-retracting needle preventing the user deploying the needle from the sheath again after using the syringe.
The syringe in accordance with the invention with a self-retracting needle comprises a body carrying injection needle support means at one end, a piston mobile in said body, a sheath inside which said body can slide, a spring disposed between the sheath and the body, at least one flexible lug cooperating abutment-fashion with a portion of the body to define a first position of immobilization of the body relative to the sheath in a first direction, the spring being compressed and the needle deployed from the sheath in this first position, and immobilizing means for immobilizing the body in the sheath in a second immobilizing position, the spring being at least partially relaxed and the needle being inside the sheath in this second position, the change from the first position to the second position being effected by cooperation of the piston with said flexible lug to release the lug from said portion of the body substantially at the end of the travel of the piston and thereby to cause the spring to retract the body into the sheath until it is immobilized in the second position.
According to the invention, the syringe is characterized in that the immobilizing means comprise a circlip mounted around said body in a compressed configuration between the sheath and the body in said first immobilizing position and in a relaxed position in said second immobilizing position, the sheath having at one end a sleeve part, the circlip having at least one part housed inside the sleeve part in said second immobilizing position between said end of the sheath and at least one shoulder of the sleeve part adapted to cooperate abutment-fashion with the circlip in said second immobilizing position to immobilize the body in the sheath in said first direction.
The circlip, which expands into the relaxed position, prevents reinsertion of the body into the sheath, which prevents deployment of the needle.
The abutting cooperation of the circlip with the end of the sheath immobilizes the body relative to the sheath in a way that is much more resistant to attempts to reinsert the body into the sheath than the flexible lugs used in syringes well known in the art, which form localized immobilizing points that are easily deformed or destroyed.
The part forming the sleeve around the sheath forms a housing for the circlip in the relaxed configuration so that the user has no access to the circlip and cannot attempt to return it to the compressed configuration in order to reinsert it into the sheath.
In a preferred version of the invention, the circlip has an L-shaped cross section and the leg of the L-shape is lodged between the sheath and the body in the second immobilizing position.
This prevents relative movement of the sheath and the syringe body not only in the longitudinal direction of the syringe but also in a transverse plane of the syringe.
Other features and advantages of the invention will become more apparent in the following description.
REFERENCES:
patent: 685979 A5 (1995-11-01), None
patent: 2680110 (1993-02-01), None
patent: WO 91/13643 (1991-09-01), None
patent: WO 92/09319 (1992-06-01), None
patent: WO 93/00949 (1993-01-01), None
patent: WO 95/23004 (1995-08-01), None
Perman & Green LLP
Yasko John D.
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