CONTROLLED RETRACTION SYRINGE AND PLUNGER THEREFOR

• US 20090093759A1
• Filed: 04/18/2006
• Published: 04/09/2009
• Est. Priority Date: 04/15/2005
• Status: Active Grant

• Current Assignee: UNL Holdings, LLC
• Original Assignee: Unitract Syringe Pty Limited (Unilife Corp.)
• Inventors: Kaal, Joseph Hermes, Judd, Damien, Thorley, Craig Stephen
• Granted Patent: US 8,167,837 B2
• Time in Patent Office: Days
• US Class Current: 604/110
• CPC Class Codes: A61M 2005/3231 Proximal end of needle captured or embedded inside piston head, e.g. by friction or hooks
• CPC Class Codes: A61M 2005/3235 triggered by radial deflection of the anchoring parts between needle mount and syringe barrel or needle housing, e.g. spreading of needle mount retaining hooks having slanted surfaces by engagement with correspondingly shaped surfaces on the piston at the end of an injection stroke
• CPC Class Codes: A61M 2005/3236 Trigger provided at the distal end, i.e. syringe end for mounting a needle
• CPC Class Codes: A61M 2005/3241 Needle retraction energy is accumulated inside of a hollow plunger rod
• CPC Class Codes: A61M 5/3234 Fully automatic needle retraction, i.e. in which triggering of the needle does not require a deliberate action by the user
• CPC Class Codes: A61M 5/502 for blocking the piston
• CPC Class Codes: A61M 5/508 Means for preventing re-use by disrupting the piston seal, e.g. by puncturing

Abstract

A retractable syringe (11) and plunger (20) therefore are provided, whereby the plunger comprises a controlling means (62) which facilitates control of the rate of retraction of the retractable needle. By controlling the rate of needle retraction, the likelihood of blood spattering is reduced, thereby improving the user-friendliness and appeal of the retractable syringe. Typically, the syringe is a prefilled syringe. Following plunger depression, a symmetrical ejector member (92) releases the retractable needle (40) from a retaining member (30) to thereby allow retraction of the retractable needle. Needle retraction is facilitated by a biasing means (70), such as a spring or other compressible and/or de-compressible device. The plunger comprises a plunger housing (21), in which is located the controlling means. The controlling means may be a pneumatic air space (324) inside the plunger housing which automatically acts against the retracting needle to thereby control or regulate the rate of retraction.

Claims

1. A plunger for a syringe having a retractable needle, said plunger comprising a controlling means which facilitates control of the rate of retraction of said retractable needle when engaged with said plunger and which is disengageable from said plunger following delivery of fluid contents of said syringe.

2. The plunger of claim 1, wherein the controlling means is operable by a syringe user to facilitate control of the rate of retraction.

3. The plunger of claim 2, which comprises a plunger housing, said controlling means being initially internally located within said plunger housing.

4. The plunger of claim 2, wherein the controlling means comprises a control member which is disengageable from said plunger.

5. The plunger of claim 4, wherein the control member is a control rod.

6. The plunger of claim 3, wherein the plunger further comprises a plunger member.

7. The plunger of claim 4, wherein the plunger member releasably engages said control member of said controlling means which is initially located within the plunger housing.

8. A syringe having a barrel, a retractable needle and a plunger engageable with said retractable needle, said plunger comprising a controlling means which facilitates control of the rate of retraction of said retractable needle when engaged with said plunger and which is disengageable from said plunger following delivery of fluid contents of said syringe.

9. The syringe of claim 8, wherein the controlling means is operable by a syringe user to facilitate control of the rate of retraction.

10. The syringe of claim 9, which comprises a plunger housing, said controlling means being initially internally located within said plunger housing.

11. The syringe of claim 10, wherein the controlling means comprises a control member which is disengageable from said plunger.

12. The syringe of claim 11, wherein the control member is a control rod.

13. The syringe of claim 12, wherein the plunger further comprises a plunger member.

14. The syringe of claim 13, wherein the plunger member releasably engages said control member of said controlling means which is initially located at least partly within the plunger housing.

15. The syringe of claim 14, which further comprises a retaining member for facilitating initial retention of said retractable needle at a needle end of said barrel.

16. The syringe of claim 15, which further comprises an ejector member operable to release said retractable needle from said retaining member to thereby allow retraction of said retractable needle when delivery of fluid contents of said syringe is complete.

17. The syringe of claim 16, wherein said ejector member does not require alignment with said retaining member to release said retractable needle from said retaining member.

18. The syringe of claim 8, wherein the syringe comprises a sealing means that comprises an inner sealing member and an outer sealing member.

19. The syringe of claim 18, wherein said inner sealing member has a tapered cross section and comprises a plurality of annular steps that engage complementary annular ribs inside said outer seal member.

20. The syringe of claim 10, wherein said retractable needle comprises a cannula and a needle body

21. The syringe of claim 20, wherein said needle body has a tapered cross section, tapering toward said cannula, and comprises a plurality of steps.

22. The syringe of claim 21, wherein said needle body is mounted to a needle mount that is located in said barrel.

23. The syringe of claim 22, wherein said needle mount comprises a plurality of complementary steps that respectively receive said plurality of steps of said needle body.

24. The syringe of claim 8, which is a prefilled syringe.

25. A prefilled syringe having a barrel;

a retractable needle;

a plunger comprising a housing and a plunger member engageable with said retractable needle;

a spring initially compressed within said plunger;

a needle seal located inside said barrel to which is mounted said retractable needle; and

a retaining member to facilitate initial retention of said retractable needle at a needle end of said barrel;

arranged so that decompression of said spring facilitates retraction of said needle and wherein said plunger further comprises a controlling means which facilitates control of the rate of retraction of said retractable needle when engaged with said plunger member and which is disengageable from said plunger following delivery of fluid contents of said syringe.

26. A plunger for a syringe having a retractable needle, said plunger comprising a pneumatic controlling means which facilitates control of the rate of retraction of said retractable needle when engaged with said plunger.

27. The plunger of claim 26, which further comprises a plunger housing, a first plunger member and a second plunger member, which co-operate to form said pneumatic means.

28. A syringe having a barrel;

a retractable needle and a plunger engageable with said retractable needle, said plunger comprising a pneumatic controlling means which facilitates control of the rate of retraction of said retractable needle when engaged with said plunger.

29. The syringe of claim 28, which further comprises a plunger housing, a first plunger member and a second plunger member, which co-operate to form said pneumatic means.

30. The syringe of claim 29, which is a prefilled syringe.

31. A prefilled syringe having a barrel;

a retractable needle;

a plunger comprising a first plunger member engageable with said retractable needle, a second plunger member and a housing;

a spring initially compressed within said plunger;

a needle seal located inside said barrel to which is mounted said retractable needle; and

a retaining member to facilitate initial retention of said retractable needle at a needle end of said barrel;

arranged so that decompression of said spring facilitates retraction of said needle and wherein said plunger further comprises a pneumatic controlling means which facilitates control of the rate of retraction of said retractable needle when engaged with said first plunger member.