Single use syringe

Abstract

A single use syringe .[.having.]. .Iadd.has .Iaddend.an interacting piston and cylinder which cooperate to define a variable volume working space.[.,.]..Iadd.; .Iaddend.the syringe includes a valve body located in the chamber so as to divide the chamber into a first and second sub-chamber, .Iadd.and .Iaddend.the valve body has valves which permit a liquid to be initially drawn into the syringe and then injected, but prevent a subsequent liquid being drawn into the syringe. .Iadd.A valve for the syringe is also claimed. .Iaddend.

We claim: 
     
       1. A single use syringe comprising: an inter-acting piston and cylinder defining a variable chamber within which a liquid to be injected is drawn;   a needle mounting at one end of said cylinder, to receive a needle, a passage extending through said mounting enabling liquid communication between said .[.cylinder.]. .Iadd.chamber .Iaddend.and said needle;   a piston rod attached to said piston and operable by a user to cause movement of said piston to vary the volume of said chamber;   a valve means including a valve body located within said chamber between said mounting and said piston and dividing said chamber into a first sub-chamber located between said mounting and valve means.[.,.]. and a second sub-chamber located between said valve means and said piston, said valve body being movable longitudinally of said cylinder between a first position and a second position, .[.and.]. .Iadd.wherein .Iaddend.said valve means includes .Iadd.1) .Iaddend.a first valve which, when said .Iadd.valve .Iaddend.body is in said first position, permits flow from said first sub-chamber to said second sub-chamber and prevents flow from said second sub-chamber to said first sub-chamber, but when said .Iadd.valve .Iaddend.body is in said second position, said first valve permits flow form said second sub-chamber to said first sub-chamber .[.and prevents flow from said first sub-chamber to said second sub-chamber,.]..Iadd., .Iaddend. and .Iadd.2) .Iaddend.a second valve which, when said .Iadd.valve .Iaddend.body is in said first position, permits flow from said first sub-chamber to said second sub-chamber, but prevents flow from said first sub-chamber to said second sub-chamber when said .Iadd.valve .Iaddend.body is in said second position.[.;.]..Iadd., .Iaddend.and   means to prevent movement of said .Iadd.valve .Iaddend.body from said second position to said first position.   
     
     
       2. The syringe of claim 1, wherein said .[.first.]. .Iadd.second .Iaddend.position of said .Iadd.valve .Iaddend.body is closer to said mounting than .[.the second.]. .Iadd.said first .Iaddend.position of said .Iadd.valve .Iaddend.body. 
     
     
       3. The syringe of claim 1 or 2.Iadd., .Iaddend.wherein said first and second valves include valve flaps attached to said .Iadd.valve .Iaddend.body, and said cylinder has recesses selectively sealingly cooperating with said valve flaps. 
     
     
       4. The syringe of claim .[.2,.]. .Iadd.3 .Iaddend.further including first projection means to engage the valve flap of said first valve, which first projection means is positioned to deflect said valve flap from sealing engagement with said cylinder when said .Iadd.valve .Iaddend.body is in said second position, and second projection means to engage .[.thje.]. .Iadd.the .Iaddend.valve flap of said second valve means to move it from sealing contact with said cylinder when said .Iadd.valve .Iaddend.body is in said first position. 
     
     
       5. The syringe of claim 1 .Iadd.or 2, .Iaddend.wherein said valve body is formed of resilient material, and said valves include resilient .[.annular.]. flanges on said .Iadd.valve .Iaddend.body, and a first projection means on said cylinder .[.and.]. positioned to engage .[.the flap.]. .Iadd.the flange .Iaddend.of .[.the.]. .Iadd.said .Iaddend.first valve when said .Iadd.valve .Iaddend.body is in said second position, and second projection means which engages the flange of said second valve when said .Iadd.valve .Iaddend.body is in said first position.Iadd., further wherein said flanges are circular.Iaddend.. 
     
     
       6. A valve assembly for a syringe having an interacting piston and cylinder, with the cylinder terminating at one end with a mounting to receive a syringe needle, said piston and cylinder co-operating to define a variable volume working chamber which receives a liquid to be injected by the syringe, said valve assembly being adapted to be located within said chamber so as to divide said chamber into a first sub-chamber located adjacent the needle mounting.[.,.]. and a second sub-chamber located adjacent the piston, said valve assembly .].including;.]. .Iadd.comprising the following components: .Iaddend. a valve sleeve to be sealingly received within said cylinder so as to be coaxial with respect thereto, said sleeve having an internal peripheral surface;   a movable valve member received within said sleeve and sealingly co-operating therewith so that in use of the syringe the valve member selectively controls the direction of flow of liquid within the syringe, said valve member having a pair of axially spaced .[.annular.]. .Iadd.circular .Iaddend.sealing surfaces which sealingly engage said sleeve, and which are resiliently deformed;   a first set of sleeve projections extending inwardly of said sleeve to engage a first one of said sealing surfaces.[.;.]..Iadd., and .Iaddend.   a second set of sleeve projections extending inwardly of said sleeve to engage the other sealing surface, said second set of sleeve projections being spaced longitudinally of said first set of sleeve projections.[.; and.]..Iadd., .Iaddend.   wherein said valve member is longitudinally movable between a first .[.portion.]. .Iadd.position .Iaddend.wherein the first .[.annular.].sealing surface is engaged with .[.the.]. .Iadd.said .Iaddend.first set of sleeve projections so as to be deformed and deflected from said sleeve so that liquid may pass thereby, and the other sealing surface is in sealing contact with said sleeve and inhibits .[.the direction of.]. fluid flow in a first direction, and a second position wherein .[.said.]. .Iadd.the .Iaddend.second sealing surface is engaged with said second set of sleeve projections so that liquid may pass thereby, and said first sealing surface is sealingly engaged with said sleeve to inhibit fluid flow in a second direction.[., which is.]. opposite to said first direction.   
     
     
       7. A single use syringe .[.having.]. .Iadd.comprising .Iaddend.an interacting piston and cylinder, with the cylinder terminating at one end with a mounting to receive a syringe needle, said piston and cylinder cooperating to define a variable volume working chamber which receives a liquid to be injected by the syringe, and .[.the.]. .Iadd.a .Iaddend.valve assembly .[.of claim 6.]., which valve assembly is located within said chamber so as to divide said chamber into .[.said.]. .Iadd.a .Iaddend.first sub-chamber and .[.said.]. .Iadd.a .Iaddend.second sub-chamber.Iadd., and which valve assembly includes the following components: a valve sleeve to be sealingly received within said cylinder so as to be coaxial with respect thereto, said sleeve having an internal peripheral surface;   a movable valve member received within said sleeve and sealingly co-operating therewith so that in use of the syringe the valve member selectively controls the direction of flow of liquid within the syringe, said valve member having a pair of axially spaced circular sealing surfaces which sealingly engage said sleeve, and which are resiliently deformed;   a first set of sleeve projections extending inwardly of said sleeve to engage a first one of said sealing surfaces, and   a second set of sleeve projections extending inwardly of said sleeve to engage the other sealing surface, said second set of sleeve projections being spaced longitudinally of said first set of sleeve projections,   wherein said valve member is longitudinally movable between a first position wherein the first sealing surface is engaged with said first set of sleeve projections so as to be deformed and deflected from said sleeve so that liquid may pass thereby, and the other sealing surface is in sealing contact with said sleeve and inhibits fluid flow in a first direction, and a second position wherein the second sealing surface is engaged with said second set of sleeve projections so that liquid may pass thereby, and said first sealing surface is sealingly engaged with said sleeve to inhibit fluid flow in a second direction opposite to said first direction. .Iaddend. .Iadd.8. A valve for a single use syringe having an interacting piston and cylinder and a syringe needle, said valve comprising:   duct means providing a passage through which liquid to be injected must pass to be delivered to said needle;   a movable valve body located in said duct means and dividing said passage into a first sub-chamber and a second sub-chamber with, said first sub-chamber to be located closer to said needle than said second sub-chamber, said valve body being movable longitudinally of said duct means between a first position and a second position under the influence of pressure applied thereto through said liquid, wherein said valve body includes 1) a first valve means sealingly co-operating with said duct means, which, when said valve body is in said first position, permits flow from said first sub-chamber to said second sub-chamber and prevents flow from said second sub-chamber to said first sub-chamber, but which, when said valve body is in said second position, permits flow from said second sub-chamber to said first sub-chamber, and 2) a second valve means which, when said valve body is in said first position, permits flow from said first sub-chamber to said second sub-chamber, but which, when said body is in said second position, prevents flow from said first sub-chamber to said second sub-chamber, and   means to prevent movement of said valve body from said second position to said first position. .Iaddend. .Iadd.9. The valve of claim 8, wherein said second position of said valve body is intended to be closer to said needle than said first position of said valve body. .Iaddend. .Iadd.10. The valve of claim 8 or 9, wherein said first and second valve means include valve flaps attached to a central portion of said valve body, and said duct means has recesses selectively sealingly co-operating with said valve flaps. .Iaddend. .Iadd.11. The valve of claim 9, wherein said valve body is formed of resilient material, and each of said valve means includes a resilient circular flange, and said each of said valve means further includes projection means on an internal peripheral surface of a sleeve positioned to engage said first valve means when said valve body is in said second position and to engage said second valve means when said valve body is in said first position. .Iaddend. .Iadd.12. The valve of claim 11, wherein said projection means includes 1) first projection means to engage said first valve means, positioned to deflect said first valve means from sealing engagement with said duct means when said valve body is in said second position, and 2) second projection means to engage said second valve means to move it from sealing contact with said duct means when said   
     
     
        valve body is in said first position. .Iaddend. .Iadd.13.  The valve of claim 9, wherein said piston and cylinder provide a primary chamber;   said valve is adapted to be located within said primary chamber so as to divide said primary chamber into said first sub-chamber, which is located adjacent the needle mounting, and said second sub-chamber, which is located adjacent said piston, and   said valve is sealingly received within said cylinder so as to be coaxial with respect thereto. .Iaddend. .Iadd.14. A single use syringe comprising the following components:   (I) an inter-acting piston and cylinder defining a variable volume primary chamber within which a liquid to be injected is drawn;   (II) a needle mounting at one end of said cylinder to receive a needle;   (III) a passage extending through said mounting enabling liquid communication between said cylinder and needle;   (IV) a piston rod attached to said piston and operable by a user to cause movement of said piston to vary the volume of said primary chamber, and   (V) a valve, through which said liquid must pass in flowing between said needle and primary chamber, which valve includes   (A) duct means providing a passage through which liquid to be injected must pass to be delivered to said needle;   (B) a movable valve body located in said duct means and dividing said passage into a first sub-chamber and a second sub-chamber, with said first sub-chamber to be located closer to said needle than said second sub-chamber, said valve body being movable longitudinally of said duct means between a first position and a second position under the influence of pressure applied thereto through said liquid, wherein said valve body includes 1) a first valve means sealingly co-operating with said duct means, which, when said valve body is in said first position, permits flow from said first sub-chamber to said second sub-chamber and prevents flow from said second sub-chamber to said first sub-chamber, but which, when said valve body is in said second position, permits flow from said second sub-chamber to said first sub-chamber, and 2) a second valve means which, when said valve body is in said first position, permits flow from said first sub-chamber to said second sub-chamber, but which, when said body is in said second position, prevents flow from said first sub-chamber to said second sub-chamber, and   (C) means to prevent movement of said valve body from said second position to said first position,   wherein said second position of said valve body is intended to be closer to said needle than said first position of said valve body. .Iaddend. .Iadd.15. The syringe of claim 14, wherein said valve body is located within said primary chamber between said mounting and piston, and said cylinder provides said passage. .Iaddend. .Iadd.16. The syringe of claim 14, wherein said valve is located in said needle mounting. .Iaddend.   
     
     
        .Iadd.7.  The valve of claim 8, wherein said second position is intended to be closer to the needle than said first position. .Iaddend. .Iadd.18. The valve of claim 17, characterized in that the flow from said first sub-chamber to said second sub-chamber can charge the syringe with liquid, while the flow from said second sub-chamber to said first sub-chamber provides for injection of the liquid from the syringe. .Iaddend. .Iadd.19. The valve of claim 18, characterized by further including annular seal means surrounding a portion of said passage and wherein said valve body engages one side of said seal means in said first position before being moved longitudinally, under the influence of said pressure, relative said seal means to said second position, at which said valve body engages the other side of said seal means to prevent flow from said first sub-chamber to said second sub-chamber. .Iaddend..Iadd.20. The valve of claim 19, wherein said first and second valve means are leading and trailing portions of said valve body with respect to movement of said valve body in the direction of movement between said first position and said second position. .Iaddend. .Iadd.21. The valve of claim 20, wherein said means to prevent movement of said valve body from said second position to said first position is in the configuration of said valve body and said seal means. .Iaddend. .Iadd.22. The valve of claim 21, wherein said seal means provides a valve opening through which said valve body passes. .Iaddend. .Iadd.23. The valve of claim 22, wherein resilient deformation permits movement of said valve body through said seal means. .Iaddend. .Iadd.24. The valve of claim 23, wherein said first and second valve means are resilient circular end walls of said valve body, which valve body includes a longitudinal stem joining the end walls. .Iaddend. .Iadd.25. The valve of claim 24, wherein said second valve means co-operates with said seal means to prevent flow from said first sub-chamber to said second sub-chamber when said valve body is in its second position, and said first valve means co-operates with said seal means to prevent flow from said second sub-chamber to said first sub-chamber when said valve body is in its first position. .Iaddend. .Iadd.26. The valve of claim 25, wherein said second valve means is resiliently deformable so as to pass through said valve opening when said valve body is moved from the first position to said second position. .Iaddend. .Iadd.27. The valve of claim 22, wherein said first and second valve means are circular end walls. .Iaddend. .Iadd.28. The valve of claim 19, which further includes annular seal means surrounding a portion of said passage, and projection means to engage said first valve means when said valve body is in said second position, wherein the valve means are valve flanges of circular configuration, and said valve body extends through said seal means when said valve body is in either said first or said second position. .Iaddend. .Iadd.29. The valve of claim 8 or 18, wherein said first and second valve means are leading and trailing portions of said valve body with respect to movement of the valve body in the direction of movement between said first position and said second position.