Self-sealed hypodermic syringe
First Claim
1. A self-sealed hypodermic syringe, comprisingan inner barrel having a rear open end,a front wall in said inner barrel, whereby a chamber is defined between said front wall and said rear open end within said inner barrel,a boss extending from said front wall having a bore therethrough in communication with said chamber,a skirt extending from said inner barrel concentric with and spaced from said boss, whereby an annular groove is formed therebetween,means for closing said bore formed to fit over said skirt,a unitary double walled stem member having an inner wall and an outer wall spaced therefrom, thereby forming an annular space therebetween having a rear closed end and a front open end,said annular space being formed to accept said inner barrel, whereby said stem member is movable between a telescoped position with said front open end proximate to said front wall and an extended position remote therefrom, and a rear tortuous path between the surrounding environment and said chamber is formed extending along the interfaces between said outer wall and said inner barrel outside surface, said rear closed end of said annular space and said rear open end of said inner barrel, and said inner wall and said inner barrel inner surface,a front stem member wall adjacent to said front open end having a hole therethrough,a resilient plunger formed for sliding motion within said inner barrel between said front wall and said rear open end,a protrusion on said resilient plunger having an enlarged end and a neck portion substantially of the same dimensions as said hole, so that when said enlarged end is deformed and forced through said hole with said neck portion engaged therein, said resilient plunger is retained in said front stem wall,a tab on said means for closing said bore extending rearwardly to overlie said outer wall when said stem member is in said telescoped position,and a breakable bond between said tab and said outer wall, whereby said bore is maintained closed and said stem member is maintained in said telescoped position isolating said chamber from the surrounding environment until said bond is broken prior to use.
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Accused Products
Abstract
A self-sealed hypodermic syringe uses Louis Pasteur'"'"'s principle of the "tortuous path" to maintain a sterile condition within a medicament chamber contained within the syringe barrel without using airtight seals. A double walled stem cooperates with the barrel to form a rear tortuous path. A needle and hub assembly cooperates with a front bore in the barrel together with an overlying needle sheath and front cap to form a front tortuous path. The front and rear tortuous paths are maintained by a breakable bond between the cap and the stem until the syringe is to be used. Another embodiment includes a pin on the front cap which cooperates with the front barrel bore in place of the needle and hub assembly.
54 Citations
11 Claims
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1. A self-sealed hypodermic syringe, comprising
an inner barrel having a rear open end, a front wall in said inner barrel, whereby a chamber is defined between said front wall and said rear open end within said inner barrel, a boss extending from said front wall having a bore therethrough in communication with said chamber, a skirt extending from said inner barrel concentric with and spaced from said boss, whereby an annular groove is formed therebetween, means for closing said bore formed to fit over said skirt, a unitary double walled stem member having an inner wall and an outer wall spaced therefrom, thereby forming an annular space therebetween having a rear closed end and a front open end, said annular space being formed to accept said inner barrel, whereby said stem member is movable between a telescoped position with said front open end proximate to said front wall and an extended position remote therefrom, and a rear tortuous path between the surrounding environment and said chamber is formed extending along the interfaces between said outer wall and said inner barrel outside surface, said rear closed end of said annular space and said rear open end of said inner barrel, and said inner wall and said inner barrel inner surface, a front stem member wall adjacent to said front open end having a hole therethrough, a resilient plunger formed for sliding motion within said inner barrel between said front wall and said rear open end, a protrusion on said resilient plunger having an enlarged end and a neck portion substantially of the same dimensions as said hole, so that when said enlarged end is deformed and forced through said hole with said neck portion engaged therein, said resilient plunger is retained in said front stem wall, a tab on said means for closing said bore extending rearwardly to overlie said outer wall when said stem member is in said telescoped position, and a breakable bond between said tab and said outer wall, whereby said bore is maintained closed and said stem member is maintained in said telescoped position isolating said chamber from the surrounding environment until said bond is broken prior to use.
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4. A self-sealed hypodermic syringe, comprising
a syringe barrel having side walls defining a medicament chamber therein and having a rear open end, a front wall in the other end of said syringe barrel, a boss on said front wall extending forwardly therefrom and having a bore therethrough in communication with said medicament chamber, a skirt on said syringe barrel surrounding said boss, a plunger cooperating with said syringe barrel side walls and said rear open end forming a tortuous rear path between the external environment and said medicament chamber, means cooperating with said skirt, boss and bore forming a front tortuous path between the external environment and said medicament chamber, and a tab extending from said last named means rearwardly to said plunger and forming a breakable bond therebetween, whereby said plunger is retained in fixed position and said tortuous front and rear paths are maintained until said bond is broken.
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8. A self-sealed hypodermic syringe comprising
a barrel defining a medicament chamber therein and having an opening at both a front and a rear end thereon, means for forming with said barrel a front tortuous path between the surrounding environment and said medicament chamber mounted on said barrel front end, a plunger assembly mounted on said barrel rear end movable between a telescoped forward position and a withdrawn rearward position, said plunger assembly forming with said barrel a rear tortuous path between the surrounding environment and said medicament chamber when in said telescoped forward position, a tab attached to said means for forming a front tortuous path extending rearwardly to overlie a portion of said plunger assembly, and a breakable bond between said tab and said plunger assembly in said telescoped forward position, whereby said front and rear tortuous paths are maintained while said breakable bond is unbroken.
Specification
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- Resources
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Current AssigneeStewart-Riess Laboratories, Inc.
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Original AssigneeStewart-Naumann Laboratories Incorporated
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InventorsXanthopoulos, Piritheos
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Primary Examiner(s)Yasko, John D.
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Application NumberUS05/828,516Time in Patent Office589 DaysField of Search128/218 R, 128/218 S, 128/218 P, 128/218 PA, 128/218 N, 128/221, 128/220, 128/234, 128/215, 128/216, 206/365, 206/571US Class Current604/192CPC Class CodesA61M 2005/3104 Caps for syringes without n...A61M 2005/3106 Plugs for syringes without ...A61M 2205/583 by visual feedbackA61M 5/31 DetailsA61M 5/3202 Devices for protection of t...A61M 5/5086 for indicating if defective...
