Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2002-05-15
2004-07-27
Casler, Brian L. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S195000, C604S218000, C604S220000, C604S240000
Reexamination Certificate
active
06767335
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention deals with a syringe of single-use type intended for injection or lab tests of the kind given in the introduction part of the following patent claim
1
.
Currently used syringes for injection are normally of single-use type and of simple design. They are mass-produced of plastic material consisting of a cover, inside which there is a movable plunger constructed in one piece with a protrusion forming a plunger pole. The plunger is equipped with a simple ring-shaped packing, and at the bottom of the cover there is a gripper for attaching a mountable injection needle which extends through the base of the cover. Before usage, a detachable needle protection cover, on the needle, protects the needle.
After usage, the syringe is usually thrown away into a special container for risk waste. Sometimes this is forgotten and the syringe may by mistake be used several times, which means considerable risks for patients.
Another disadvantage about conventional single-use syringes involves accidental risk for personnel by the fact they may easily get stung when handling it. Normally, as mentioned, the syringe needle is protected by a needle protection cover before usage. This should be re-applied onto the needle after usage, before throwing away the syringe. The opening of the needle protection cover is of small diameter, although to some extent conical shaped, and it may be hard to move the needle into the opening, safely. If you miss some time, there is a considerable risk of pricking your finger, and this risk is imminent when working in situations when there is little time and stress. The frequency of incidents for personnel who often handle syringes of this kind, is as high as 80%, according to an investigation counting the number of incidents when people prick their fingers, occurring at least once per person. Even already used, loose injection needles imply risks, even when contained in risk waste containers, since it happens that needles penetrate container walls.
To avoid or prevent these potential incidents, it is known to have a coupling device applied to the plunger part facing the cover base, by which the plunger when maximally pushed in may be connected to the inner end of the needle, after which the needle may be retracted into the space between the cover base and the plunger, by maximally pulling it out. In this position, however, the syringe may not be thrown away, since there is a risk that the maximally protruding plunger pole may be somewhat pushed in, thus making the needle protrude from the cover base.
There is, however, the possibility of turning the plunger pole and thereby the plunger, to some extent, so that the needle is displaced sideways a bit, and thereafter break the plunger pole. A disadvantage then is that the plunger by bending tensions may become tilted or the syringe cover breaks, so that remaining liquid in the syringe may leak out.
Another well-known solution as regards the protruding plunger pole consists in after having turned the plunger pole somewhat, slightly reminiscent of above-mentioned turning, the whole plunger is pushed back, whereby the needle end hits the cover base, and the needle is strongly bent backwards. A certain amount of force is required for this, and in unfortunate cases it may happen that the needle end penetrates the base, whereby there is considerable risk of the needle penetrating into the hand that holds the cover base of the syringe.
Yet another known solution to the problem of encasing the injection needle after usage inside the syringe, consists in applying, according to EP 0413414, a mechanism in the cover base, which upon the pressure of the plunger on the cover base pushes in a cap exposing a hole through the plunger ending in a space behind the plunger, simultaneously releasing the needle attachment device in the cover base, permitting a spring mechanism to throw the needle backwards in the syringe into aforementioned space behind the plunger front end, which is a cavity inside the plunger pole. This is an expensive and complicated syringe, which furthermore has the disadvantage that the needle has to be assembled upon manufacturing the syringe and cannot be replaced, if needed, afterwards, in which case the whole syringe must be replaced
SUMMARY OF THE INVENTION
The object of the present invention is to achieve a single-use syringe of afore-mentioned kind, which combines simplicity with higher security for avoiding accidents when handling the syringes, compared to known syringes.
This has, according to the invention, been achieved by giving the syringe the characteristics that are indicated in patent claim
1
. Instead of making the needle bent, which is the case in one of the known solutions, will the solution according to the invention, after having pushed in the plunger a second time after having dragged in the needle into the space between the cover base and the plunger, involve the pushing of the needle through a hole penetrating the plunger until the needle point is positioned closely level with the front face of the plunger with the rest of the needle in the plunger and a space behind it. For this push-in of the plunger, less force is required compared to the known solution whereby the needle was bent and shortened, and this means that the risk of pushing the needle through the cover base is negligible. Preferably, the needle point part be safely held fast in the front end of the plunger by equipping the penetrating hole in the plunger with a surrounding, embracing, elastic device as indicated in claim
2
.
Other preferred embodiments of the syringe according to the invention are stated in the sub-claims and the folloeing description.
REFERENCES:
patent: 4955869 (1990-09-01), Bin
patent: 5064419 (1991-11-01), Gaarde
patent: 5242402 (1993-09-01), Chen
patent: 5496278 (1996-03-01), Buff
patent: 5531694 (1996-07-01), Clemens et al.
patent: 5533975 (1996-07-01), Lu
patent: 5562627 (1996-10-01), Chen
patent: 6050974 (2000-04-01), Allard et al.
patent: 6074370 (2000-06-01), Pressly et al.
patent: 6117107 (2000-09-01), Chen
patent: 6179812 (2001-01-01), Botich et al.
patent: 6206857 (2001-03-01), Chen
patent: 0 413 414 (1991-02-01), None
Casler Brian L.
Frishauf Holtz Goodman & Chick P.C.
HelgMediTech AB
Thissell Jeremy
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