Syringe with an improved needle retraction mechanism

A syringe kit, said syringe kit comprising a syringe assembly and an injection assembly, said syringe assembly comprising:

• a. a cylindrical barrel comprising a hollow body, wherein the hollow body is at least partly filled with an injectable liquid;
• b. a hollow plunger positioned within said hollow body of said cylindrical barrel;
• c. a rod connected to or integral with said plunger and extending at least partly into said hollow body of said cylindrical barrel, wherein each of said rod and said plunger has an axial hole passing therethrough;
• d. an extractor element is positioned within said axial hole of said plunger and within said hole of said rod;
• e. a recovery tension or compression spring connected to said extractor element;
• and
• said injection assembly comprising:
• a. a hollow nose end;
• and
• b. a needle holder positioned in said nose end, wherein said needle holder comprises an internal cavity;
• wherein
• the syringe assembly and the injection assembly respectively comprise a first connective part and a second connective part, said first and second connective part are configured to allow both a closed kit configuration and an open kit configuration, said closed kit configuration comprising the air-tight connection of the syringe assembly to the injection assembly, wherein the internal cavity of the needle holder and the hollow body of the cylindrical barrel are configured to form a continuous channel which allows the passage of the injectable liquid, and said open kit configuration comprising the air-tight sealing of the syringe assembly without connection of the injection assembly;
• the extractor element is movably displaceable from an advanced position, surrounded by said plunger with a portion protruding in the first connective part direction, and a retracted position, fully retracted into said rod, positioned away from said first connective part;
• the extractor element has a male protrusion, protruding in said advanced position to engage said internal cavity of said needle holder to join said extractor element to said needle holder, and hooking means defining a connection between said plunger and said extractor element to maintain said extractor element in said advanced position and to maintain the recovery spring under tension or compression;
• characterized in that, the axial hole of the plunger is defined by a at least two bendable flanges which are configured to slidably engage with the needle holder, said bendable flanges thereby bending outwardly and expanding the axial hole of the plunger, and whereby the extractor element is disconnected from said plunger and is retracted towards its retracted position.

A method of manufacturing a syringe kit, comprising:

• assembling or providing a syringe assembly comprising the following parts:
• a. a cylindrical barrel comprising a hollow body;
• b. a hollow plunger positioned within said hollow body of said cylindrical barrel;
• c. a rod connected to or integral with said plunger and extending at least partly into said hollow body of said cylindrical barrel, wherein each of said rod and said plunger has an axial hole passing therethrough;
• d. an extractor element is positioned within said axial hole of said plunger and within said hole of said rod;
• and
• e. a recovery tension or compression spring connected to said extractor element;
• assembling or providing a needle assembly comprising the following parts:
• a. a hollow nose end;
• and
• b. a needle holder positioned in said nose end, wherein said needle holder comprises an internal cavity;
• wherein
• the syringe assembly and the injection assembly respectively comprise a first connective part and a second connective part, said first connective part allowing the air-tight sealing of the hollow body of the barrel, and the air-tight connection to the second connective part of the injection assembly, wherein the internal cavity of the needle holder and the hollow body of the cylindrical barrel are configured to form a continuous channel which allows the passage of the injectable liquid,
• the extractor element is movably displaceable from an advanced position, surrounded by said plunger with a portion protruding in the first connective part direction, and a retracted position, fully retracted into said rod, positioned away from said first connective part;
• the extractor element has a male protrusion, protruding in said advanced position to engage said internal cavity of said needle holder to join said extractor element to said needle holder, and hooking means defining a connection between said plunger and said extractor element to maintain said extractor element in said advanced position and to maintain the recovery spring under tension or compression;
• and wherein
• the axial hole of the plunger is defined by at least two bendable flanges which are configured to slidably engage with the needle holder, said bendable flanges thereby bending outwardly and expanding the axial hole of the plunger, and whereby the extractor element is disconnected from said plunger and is retracted towards its retracted position;
• filling the hollow body of the cylindrical barrel at least partly with an injectable liquid;
• air-tightly closing the hollow body of the cylindrical barrel.