Vaccination syringe
A replaceable needle assembly is provided for a retractable, prefilled syringe comprising a barrel having a mounting member and a plunger, whereby the retractable needle can be replaced by a user without affecting the retraction mechanism. The replaceable needle assembly comprises a needle fitted to a retractable needle mount and a needle retainer. The needle mount is removably, screw-threadedly mountable to the mounting member of the barrel. The needle retainer comprises a plurality of fingers that releasably engage the retractable needle to thereby prevent inadvertent retraction of the retractable needle before engagement by the plunger. The plunger comprises a plunger seal comprising an outer member and an inner member that engages the needle for spring-driven retraction. At the end of retraction, a lock is formed between the plunger and barrel to prevent re-use of the syringe.
1. A plunger for a retractable syringe comprising a barrel including a mounting member to which is mountable a replaceable needle assembly, the plunger comprising:
a biasing means;
a plunger member releasably connected to a control rod;
a plunger housing; and
a plunger seal mounted to the plunger member; wherein the control rod comprises a flexible arm configured to initially engage the plunger housing, engagement of the flexible arm and the plunger housing maintaining the biasing means in an initially energized state prior to retraction, wherein the plunger member comprises a needle-engaging portion configured to engage a retractable needle of the replaceable needle assembly to facilitate needle retraction and the plunger housing comprises one or more lock elements configured to form a lock with the barrel, or a barrel collar, after retraction.
2. The plunger of claim 1 , wherein the plunger housing comprises an arm having a shoulder configured to lock onto the barrel or barrel collar.
3. The plunger of claim 2 , wherein the barrel collar comprises a release ring that comprises a rim, wherein the shoulder locks onto the rim of the release ring.
4. The plunger of claim 1 , wherein the control rod is configured to disengage from the plunger housing to facilitate a release of energy from the biasing means to thereby retract the control rod and the plunger member.
5. The plunger of claim 1 , wherein the biasing means is a spring.
6. A retractable syringe kit comprising:
a barrel prefilled with fluid contents, the barrel including a mounting member to which is removably mountable a replaceable needle assembly;
a plurality of replaceable needle assemblies; and
a plunger including:
a biasing means,
a plunger member releasably connected to a control rod,
a plunger housing, and
a plunger seal mounted to the plunger member; wherein the control rod comprises a flexible arm configured to initially engage the plunger housing, engagement of the flexible arm and the plunger housing maintaining the biasing means in an initially energized state prior to retraction, wherein the plunger member comprises a needle-engaging portion configured to engage a retractable needle of each of the replaceable needle assemblies to facilitate needle retraction and the plunger housing comprises one or more lock elements configured to form a lock with the barrel, or a barrel collar, after retraction.
7. The retractable syringe kit of claim 6 , wherein the plurality of needle assemblies comprises a 0.5 inch needle, a 1.0 inch needle, and a 1.5 inch needle.
8. The retractable syringe kit of claim 6 , further comprising a plug removably mounted to the mounting member of the barrel.
9. The retractable syringe kit of claim 6 , wherein the replaceable needle assemblies each further include a needle mount removably mountable to the mounting member of the barrel and a needle retainer configured to prevent inadvertent retraction of the retractable needle.
10. A retractable syringe comprising:
a barrel including a mounting member;
a replaceable needle assembly removably mounted to the mounting member of the barrel and including a retractable needle; and
a plunger including:
a biasing means,
a plunger member releasably connected to a control rod,
a plunger housing, and
a plunger seal mounted to the plunger member; wherein the control rod comprises a flexible arm configured to initially engage the plunger housing, engagement of the flexible arm and the plunger housing maintaining the biasing means in an initially energized state prior to retraction, wherein the plunger member comprises a needle-engaging portion configured to engage a retractable needle of the replaceable needle assembly to facilitate needle retraction and the plunger housing comprises one or more lock elements configured to form a lock with the barrel, or a barrel collar, after retraction.
11. The retractable syringe of claim 10 wherein the replaceable needle assembly further includes a needle mount removably mountable to the mounting member of the barrel and a needle retainer configured to prevent inadvertent retraction of the retractable needle.
12. A method of operating a retractable syringe comprising a barrel and a plunger according to claim 1 , comprising:
removably mounting a replaceable needle assembly comprising a retractable needle engageable by the plunger, a needle mount, and a needle retainer to the barrel of the retractable syringe.
13. The method of claim 12 , wherein the barrel is prefilled with fluid contents.
14. The method of claim 12 , further comprising removing a plug from a mounting member of the barrel prior to removably mounting the replaceable needle assembly to the mounting member.
15. The method of claim 12 , further comprising screw-threadedly mounting the needle mount to a mounting member of the barrel.
16. A method of making a pre-filled syringe comprising:
coupling a plunger according to claim 1 and a plunger seal in a syringe barrel, wherein the syringe barrel is prefilled with fluid contents and comprises a plug member removably mounted thereto or a replaceable needle assembly removably mounted thereto.