Retractable needle single use safety syringe

• US 7,481,797 B2
• Filed: 11/03/2006
• Issued: 01/27/2009
• Est. Priority Date: 11/28/2001
• Status: Expired due to Fees

• Current Assignee: Universal Safetmed Devices LLC
• Original Assignee: Sakharam D. Mahurkar
• Inventors: Mahurkar, Sakharam D.
• Primary Examiner(s): Lucchesi; Nicholas D
• Assistant Examiner(s): VU, QUYNH-NHU HOANG
• Application Number:
  US11/592,952
• Publication Number:
  US 20070060893A1
• Time in Patent Office: 816 Days
• Field of Search: 604/187, 604/110, 604/192, 604/194, 604/195, 604/164.01, 128/919
• US Class Current: 604/195
• CPC Class Codes: A61M 2005/3206 Needle or needle hub disconnecting devices forming part of or being attached to the hub or syringe body
• CPC Class Codes: A61M 25/0606 "Over-the-needle" catheter assemblies, e.g. I.V. catheters
• CPC Class Codes: A61M 25/0631 having means for fully covering the needle after its withdrawal, e.g. needle being withdrawn inside the handle or a cover being advanced over the needle
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence
• CPC Class Codes: A61M 5/3232 Semi-automatic needle retraction, i.e. in which triggering of the needle retraction requires a deliberate action by the user, e.g. manual release of spring-biased retraction means

Abstract

A safety syringe assembly includes an elongated, generally cylindrical barrel having a hollow interior forming a hollow nozzle located at a distal end of the barrel and opening into the interior of the barrel. A plunger is slidably mounted in the barrel and has a longitudinal open channel. A needle holder mounts a needle at a distal end thereof and is slidably mounted in the longitudinal open channel of the plunger for movement between an advanced position in which the needle on the distal end of the needle holder projects from a distal end of the nozzle, and a retracted position in which the needle is retracted within the barrel. A compression spring is mounted inside of the barrel, and a spring retainer element has a spring support portion extending from the interiorly of the barrel to a portion for mounted within the barrel and supporting a distal end portion of the spring against expansion. The spring urges the needle holder toward its retracted position. A latch has a closed position in which the needle holder is latched relative to the barrel to hold the needle holder in its advanced position against the urging of the spring, and an open position in which the needle holder is unlatched relative to the barrel to allow the spring to expand in a proximal direction to move the needle holder to its retracted position.

Claims

1. A safety syringe assembly, comprising:

an elongated, generally cylindrical barrel having a hollow interior forming a hollow nozzle located at a distal end of said barrel and opening into the interior of said barrel;

a plunger slidably mounted in said barrel and having a longitudinal open channel;

a needle;

a needle holder mounting said needle at a distal end thereof and slidably mounted in said longitudinal open channel of said plunger for movement between an advanced position in which said needle on the distal end of said needle holder projects from a distal end of said nozzle, and a retracted position in which said needle is retracted within said barrel;

a compression spring mounted inside of said barrel, and a spring retainer element located in and locked to said barrel and having a stabilizing surface extending along and about a portion of the internal wall of said barrel, and a spring support portion extending from said stabilizing surface interiorly of said barrel and supporting a distal end portion of said spring against expansion, said spring retainer also having a through opening for freely receiving said needle holder therethrough;

said spring urging said needle holder toward its retracted position; and

a latch having an engaged position in which said needle holder is latched relative to said barrel to hold said needle holder in its advanced position against the urging of said spring, and a disengaged position in which said needle holder is unlatched relative to said barrel to allow said spring to expand in a proximal direction to move said needle holder to its retracted position.

2. A retraction control unit for the safety syringe assembly of claim 1, wherein:

said spring retainer element has a distal axial cantilever extension, inserted co-axially and locked within said barrel;

said plunger has a compressibly engaged resilient cap, and one or more radial projections, is capable of reciprocal linear movements, and is inserted within said spring retainer clearing the cantilever;

said needle holder is slidably mounted in said open channel of said plunger for movement between an advanced position in which a needle on the distal end of said needle holder projects from a distal end of said nozzle, and a retracted position in which said needle is retracted within said barrel;

said spring retainer element forms a distal axial cantilever extension retaining a compression spring wrapped around said needle holder, such that said needle holder passes distally through an opening in the said axial extension; and

a proximal surface of said spring retainer element has a stabilizer plate to support the needle holder and a deflectable anchoring plate that releasably holds the needle holder against an expansion force of the spring until it is radially deflected by the projections of said plunger, in response to a force that exceeds a fluid injection force.

3. The safety syringe assembly of claim 1 in which said barrel includes an expanded proximal segment, and said spring retainer element is located in and locked to said expanded proximal segment of said barrel.

4. A retraction control module for a retractable needle safety syringe having a barrel with a hollow interior, said module comprising:

a hollow cylindrical tube with a distal axial extension forming a central cantilever with a central through opening, and a proximal eccentric anchoring plate forming an engagement geometry to engage and anchor a needle holder to the module, said hollow cylindrical tube being anchored to the proximal end of said barrel;

said needle holder having an advanced position in which a needle on the distal end of said needle holder projects from a distal end of said syringe, and a retracted position in which said needle is retracted within said syringe;

a helical compressed spring encircling the needle holder and supported by said axial extension and the central cantilever with the needle holder and an attached needle passing through the central through opening of said cantilever, and within the tube; and

a plunger compressibly engaged with a resilient cap passing through said cylindrical tube and having two parallel walls defining a central open channel that contact with the eccentric anchoring plate without deflecting said anchoring plate;

said plunger having a distally advanced position and ramps on said parallel walls which deflect the anchoring plate radially to disengage the needle holder and cause retraction of the needle when the plunger is advanced to said distally advanced position;

said needle holder being slidably mounted in said central open channel of said plunger;

said anchoring plate with extension arising from the opposite surface of the hollow cylinder from said distal axial extension and engaging with a proximal part of the needle holder preventing the expansion of said spring.

5. The retraction control module of claim 4 which, when engaged to a syringe barrel, converts a conventional syringe into a retractable needle safety syringe.

6. A retraction control module as set forth in claim 4, wherein retraction as a result of deflection and release of the needle holder from the anchoring plate by the plunger ramps is responsive to the advance of the plunger in the cylindrical tube to complete an injection.

7. A retractable needle safety syringe with said retraction control unit as set forth in claim 4, further comprising a closed needle protector, wherein a nozzle formed by said cylindrical tube has a male luer taper on its outer surface that mates with a female luer taper interior of said needle protector creating a taper lock to form an air and water tight seal between said nozzle and said needle protector, whereby air or fluids residing in the sealed cylindrical tube prevent advance of the plunger to the distal end of the cylindrical tube, avoiding retraction before the use of the syringe.

8. A retractable needle safety syringe comprising said retraction control module as set forth in claim 4 and an over-the-needle catheter located on and inserted synchronously with said needle into a vein, said catheter remaining in the vein while said needle is retracted.

9. The retraction control module as set forth in claim 4 wherein the plunger has linear axial mobility independent of movements of the spring and needle holder, and wherein, upon retraction of the needle, every component of the syringe is directly or indirectly locked with every other component of the syringe, such that the entire assembly is interlocked whereby the syringe is non-reusable.

10. The retraction control module as set forth in claim 4, wherein a proximal open end of said needle faces said distal end of said needle holder and communicates with said cylindrical tube by a side opening.

11. A retraction control unit for a retractable needle syringe comprising:

a spring retainer with a distal axial cantilever extension, inserted co-axially and locked within a barrel of a syringe;

a plunger with a compressibly engaged resilient cap, one or more radial projections and a central channel and capable of reciprocal linear movements, and engaged with said spring retainer clearing the cantilever;

a needle holder slidably mounted in said central open channel of said plunger for movement between an advanced position in which a needle on the distal end of said needle holder projects from a distal end of a nozzle, and a retracted position in which said needle is retracted within said barrel; and

a seal between said needle holder and an inside surface of said nozzle to retain liquid within said barrel,

the distal axial cantilever extension of the said spring retainer retaining a compression spring wrapped around said needle holder, such that said needle holder passes distally through an opening in the said axial extension,

a proximal surface of said spring retainer having a deflectable anchoring plate that releasably holds the needle holder against an expansion force of the spring until it is radially deflected by the projections of said plunger, in response to a force that exceeds a fluid injection force, the deflection of said anchoring plate allowing said spring to retract said needle holder.

12. A retraction control unit for a retractable needle syringe as set forth in claim 11, wherein said plunger includes a detent on a plunger flange for engaging a latch, so as to interlock said syringe.

13. A retraction control unit for a retractable needle syringe as set forth in claim 11, further comprising a closed needle protector, wherein said nozzle of said barrel has a male luer taper on its outer surface that mates with a female luer taper interior of said needle protector creating a taper lock to form an air and water tight seal between said nozzle and said needle protector, whereby air or fluids residing in the sealed barrel prevent advance of the plunger to the distal end of the barrel, avoiding retraction before the use of the syringe.

14. A retraction control unit for a retractable needle syringe as set forth in claim 11, further comprising an over-the-needle catheter, said catheter being located on and inserted synchronously with said needle into a vein, said catheter remaining in the vein while said needle is retracted.

15. A retraction control unit for a retractable needle syringe as set forth in claim 11, wherein a proximal open end of said needle faces said distal end of said needle holder and communicates with said barrel by a side opening.

16. A retraction control unit for a retractable needle syringe as set forth in claim 11, wherein the retraction of said needle holder as a result of deflection of said anchoring plate is responsive to the advance of said plunger in said barrel to complete an injection.

17. A retraction control unit for a retractable needle syringe as set forth in claim 11, wherein said spring retainer is engaged to the barrel by one of a mechanical fit, a chemical bond and an ultrasonic bond.

18. A retraction control unit for a retractable needle safety syringe having a barrel with a hollow interior, said module comprising:

a needle holder having an advanced position in which a needle on the distal end of said needle holder projects from a distal end of said syringe, and a retracted position in which said needle is retracted within said syringe,

a hollow spring retainer with a distal axial extension forming a central cantilever with a central through opening, and a proximal eccentric anchoring plate forming an engagement geometry to engage and anchor said needle holder to the control unit, said hollow spring retainer being anchored to the proximal end of said barrel;

a helical compressed spring within said spring retainer and encircling said needle holder and supported by said axial extension and said central cantilever, with said needle holder and an attached needle passing through said central through-opening of said cantilever;

a plunger compressibly engaged with a resilient cap having a through-opening communicating with said spring retainer and having two parallel walls defining a central open channel that contacts said eccentric anchoring plate without deflecting said anchoring plate said plunger having a distally advanced position and ramps on said parallel walls which deflect the anchoring plate radially to disengage the needle holder and cause retraction of the needle when the plunger is advanced to said distally advanced position; and

a seal between said needle holder and an inside surface of said nozzle to retain liquid within said barrel,

said needle holder being slidably mounted in said central open channel of said plunger, and

said anchoring plate with extension arising from said opposite surface of said spring retainer from said distal axial extension and engaging a proximal part of said needle holder to prevent the expansion of said spring.

19. The retraction control unit of claim 18 wherein said spring retainer is engaged to said barrel by one of a mechanical fit, a chemical bond and an ultrasonic bond.

20. The retraction control unit of claim 18 wherein when said anchoring plate is engaged with said needle holder, said needle holder is urged distally through said seal for normal use, and when disengaged the expanded spring of the control unit urges the needle and the needle holder inside the barrel.

21. The retraction control unit of claim 18 wherein hydraulic forces in the syringe do not affect the retraction control unit because said unit is outside a fluid chamber defined in the syringe.

22. Retraction control unit as claimed in claim 18, wherein retraction as a result of deflection and release of the needle holder from the anchoring plate by the plunger ramps is responsive to the advance of the plunger in the barrel to complete an injection.

23. A retractable needle safety syringe with said retraction control unit as set forth in claim 18, further comprising a closed needle protector, wherein said nozzle of said barrel has a male luer taper on its outer surface that mates with a female luer taper interior of said needle protector creating a taper lock to form an air and water tight seal between said nozzle and said needle protector, whereby air or fluids residing in the sealed barrel prevent advance of the plunger to the distal end of the barrel, avoiding retraction before the use of the syringe.

24. A retractable needle safety syringe as set forth in claim 18 further comprising an over-the-needle catheter, said catheter being located on and inserted synchronously with said needle into a vein, said catheter remaining in the vein while said needle is retracted.