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EP0478281A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Single-use syringe

Assignee: MEDI PLUS TEC MEDIZINISCH-TECHNISCHE HANDELSGESELL
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Filing: 1991-09-24
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Granted: —
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Expires: 2011-09-24
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Abstract

Abstract A single-use syringe has a piston assembly sealingly slidable within a barrel. The piston assembly has a plunger (1) with a divergently tapered portion (4) and a resiliently deformable piston (2) with a through aperture (7), correspondingly tapered so that part of the tapered portion (4) may fit within the aperture, and a tapered skirt portion (6) adapted to surround a further part of the tapered portion (4). The through aperture is adapted to be plugged by the plunger. A locking ring (3) having a tapered aperture to surround said skirt portion is provided to hold the skirt (6) against the plunger end portion (4). When the plunger (1) is depressed within the barrel, the locking ring (3) is delayed by the wall of the barrel while the skirt (6) is pushed inwardly. Once the skirt (6) is unrestrained by the locking ring (3), outward movement of the plunger (1) will cause its end portion (4) to be pulled free from the piston (2). The piston (2) is thus non-retractable to prevent a second drawing-in of liquid.

Inventors

  • 👤 William Thomas Dennis Bates

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-05 17:26
CPC Classifications
A; A61; A61M; A61M5/00; A61M5/50; A61M5/5066; A61M5/508; A61M5/5013; A61M5/502; A61M2005/5026

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 103 words
A single-use syringe comprising a piston assembly sealingly slidable within a barrel (5), the piston assembly having a plunger (1) with a divergently tapered portion (4), a resiliently deformable piston (2) having a tapered skirt portion (6) adapted to surround at least a part of the plunger tapered portion, and a locking ring (3) having a tapered aperture to surround said skirt portion and being in sliding frictional engagement with the barrel of the syringe; characterised in that said piston has a through aperture (7) adapted to be plugged by said plunger, and said tapered skirt portion extends coaxially with said through aperture.
Claim 2
Dependent Claim 32 words
A syringe according to claim 1, wherein said plunger has a plug (8) extending from said divergently tapered portion, the plug being dimensioned to fill a forward portion of said through aperture.
Claim 3
Dependent Claim 12 words
A syringe according to claim 2, wherein said plug is convergently tapered.
Claim 4
Dependent Claim 42 words
A syringe according to claim 3, wherein said through aperture is dimensioned with a divergent taper corresponding to an end part of said plunger tapered portion and a convergent taper at said forward portion corresponding to the convergent taper of said plug.
Claim 5
Dependent Claim 15 words
A syringe according to any preceding claim, wherein said locking ring is a split ring.
Claim 6
Dependent Claim 36 words
A syringe according to any preceding claim, wherein the angle of taper of said plunger tapered portion is in the region of between 1 and 10 degrees with respect to the longitudinal axis of the plunger.
Claim 7
Dependent Claim 20 words
A syringe according to claim 6, wherein the angle of taper is in the region of 1.5 to 5.0 degrees.
Claim 8
Dependent Claim 18 words
A syringe according to claim 7, wherein the angle of taper is in the region of 2 degrees.
Claim 9
Dependent Claim 33 words
a syringe according to claim 2, wherein the forward portion of the through aperture cooperable with said plug has a diameter between one third and one quarter of the diameter of the piston.
Claim 10
Dependent Claim 44 words
A syringe according to any preceding claim, wherein provision is made for an elongate member to maintain pressure on the locking ring during insertion of the piston assembly into the barrel, whereby the locking ring is kept in engagement with the tapered skirt portion.

References Cited (Backward Citations)

GB2015883A Cited
EP0304386A2 Cited
EP0329358A2 Cited
EP0336855A1 Cited
GB2220143A Cited

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