Safety device for hypodermic needle or the like

Abstract

A safety device for a hypodermic needle or for a similar instrument used in the clinical puncture of the skin comprises a sheath (6, 25 or 32) adapted to be connected to the needle (5, 21 or 33) or to a support (4 or 31) for the needle. The sheath is so connected in a first position (FIGS. 1A, 2A, or 3A) which permits normal use of the needle and can be placed, by movement relative to the needle (FIGS. 1B or 3B) or by folding upon itself (FIGS. 2B and 2C) in a second position in which the needle is encapsulated by the sheath. The sheath is retained in that second position, for example by a projection (9, 27 or 35) extending into a slot (10 or 36) or through an aperture (28).

Description

This is a continuation of Ser. No. 08/160,859 filed Dec. 3, 1993 .The thumb guard 7 constitutes a lateral enlargement of the guard and as illustrated in FIG. 2A has an arcuate surface 7a providing a finger-engaging surface. The needle housing 4 thus comprises a hollow support structure and forms with needle 5 a sub-assembly. Also incorporated in the housing 4 and running length-wise, is a channel 8. The sheath 6 incorporates a self-springed spigot 9, which slides along the channel 8, as shown in more detail in the enlarged inset. When the sheath travels to the end of the channel 8, the self-springed spigot 9 drops into a small "well" 10, thus locking the sliding sheath in position. The length of the sheath is such that, when it is locked in position, the sharp end of the needle is completely enclosed by the sheath, as shown in FIG. 1B.

The housing 4 is designed to mate with any standard syringe barrel or luer connector. After use, the protective sheath is extended into the locked position, thus encapsulating the needle in a safe manner.

The embodiment of the invention shown in FIGS. 2A to 2C 3 and 4A-4C is designed to allow encapsulation of a hypodermic needle 21 which is tethered to a syringe (not shown) by an extension tube 22. The needle 21 is sandwiched between two plastics mouldings or pressings 23,24 which together form a sheath 25. A part 26 of the sheath 25 is permanently attached to the hypodermic needle. At points 23a and 24a the plastic is formed in a manner which allows the free ends of members 23 and 24 to hinge as indicated Near to its outer end, the member 23 carries two spigots 27, which are designed to mate with holes 28 in the member 24 (when the sheath is in its folded position) and lock the sheath securely around the needle 21.

The third embodiment of the invention, as illustrated in FIGS. 5A and 5B 5A-5C, comprises a needle housing 31 in the form of a plastics moulding, a plastics sheath 32 which is free to rotate thereon and a needle 33. Impressed into the housing 31 is helical groove 34 extending from near the end of the housing 31 which is distal to the needle 33 towards the needle. The sheath 32 has a self-springed spigot 35 which fits into, and is free to move along, the helical groove 34 while subject to a biasing force acting between the sheath 32 and housing 31 during relative movement of the sheath and housing. As shown in FIG. 3B 5B, rotation of the sheath 32 in a clockwise direction (viewed from the rear) will result in a forward motion causing the sheath to encapsulate the needle 33. At the end of its travel the springed spigot 35 drops into a "well" 36 thereby locking the sheath in position. The length of the sheath 32 is such that when it has reached this locked position the needle is completely encapsulated and withdrawn beyond the orifice 37 in the outer end of the sheath.

The device shown in FIGS. 3A and 3B 5A-5C is designed to mate with any standard syringe barrel or luer connector. For example, as illustrated in FIG. 2A, a connector formation is provided on an elongate body 40 including a tapered abutment surface 42 for mating with the needle support housing and having a complementary tapered abutment surface 44. After use, the protective sheath is placed in position by applying a twisting force to the sheath. To facilitate the application of this twisting force, a raised section 38 may be incorporated into the sheath's surface.

This form of the invention may be fabricated with one or more helical grooves, which may extend in a clockwise or anti-clockwise direction. For greater mechanical strength and stability, a double helix may be preferred.

In FIG. 6, the groove 34a and spigot 35a are formed in the sheath 32a and housing 31a, respectively, i.e., reversed as previously described from the configuration of FIGS. 5A-5C.

Claims

1. For use with clinical apparatus operably applicable to a patient by way of a deliberate skin puncture, a needle assembly operable to effect said skin puncture and comprising:

a support structure;

a needle fixedly mounted in said structure to form therewith a sub-assembly, with one end portion of said needle projecting from said structure, and said one end portion terminating in a skin-puncturing tip;

a guard mounted around part of said sub-assembly for movement relative thereto in the longitudinal direction of said needle from a first position in which said tip is exposed to effect said deliberate puncture, to a second position in which said tip is embraced by said guard to prevent unintended skin puncture;

a locking mechanism including first and second elements, said first element being a projection from one of said sub-assembly and guard, said second element being a stop surface defining a space bordering the other of said sub-assembly and guard, said elements each extending transversely of said needle longitudinal direction, said elements being spaced apart in said longitudinal direction when said guard is in said first position, said projection being subject to a bias force acting between said sub-assembly and guard during said relative movement, and said projection being automatically irreversibly moved into said space alongside said stop surface in response to said bias force when said guard is in said second position to inhibit a returning relative movement thereof towards said first position; and

a stop mechanism effective to constrain said guard from movement towards and around said apparatus.

2. An assembly according to claim 1 wherein said locking mechanism second element stop surface defines said space as a recess in the other of said sub-assembly and guard.

3. An assembly according to claim 1 wherein, to serve as said stop mechanism, said support structure has a portion with external dimensions transversely of said longitudinal direction which are enlarged relative to the remainder of the structure, and said guard has lesser corresponding internal transverse dimensions around said structure than said portion.

4. For use with clinical apparatus operably applicable to a patient by way of a deliberate skin puncture, a needle assembly operable to effect said skin puncture and comprising:

a support structure;

a needle fixedly mounted in said structure to form therewith a sub-assembly, with one end portion of said needle projecting from said structure, and said one end portion terminating in a skin-puncturing tip;

a guard mounted around part of said sub-assembly for movement relative thereto in the longitudinal direction of said needle from a first position in which said tip is exposed to effect said deliberate puncture, to a second position in which said tip is embraced by said guard to prevent unintended skin puncture;

a locking mechanism including first and second elements, said first element being a projection from one of said sub-assembly and guard, said second element being a stop surface defining a space bordering the other of said sub-assembly and guard, said elements each extending transversely of said needle longitudinal direction, said elements being spaced apart in said longitudinal direction when said guard is in said first position, said projection being subject to a bias force acting between said sub-assembly and guard during said relative movement, and said projection being automatically irreversibly moved into said space alongside said stop surface in response to said bias force when said guard is in said second position to inhibit a returning relative movement thereof towards said first position;

a stop mechanism effective to constrain said guard from movement towards and around said apparatus;

said stop mechanism including a portion of said support structure having external dimensions transversely of said longitudinal direction which are enlarged relative to the remainder of the structure, and said guard having lesser corresponding internal transverse dimensions around said structure than said portion;

said support structure having a connector formation for removable attachment with said clinical apparatus, which formation includes said transversely enlarged portion.

5. For use with clinical apparatus operably applicable to a patient by way of a deliberate skin puncture, a needle assembly operable to effect said skin puncture and comprising:

a hollow support structure;

a needle fixedly mounted on said structure adjacent one end thereof to form therewith a sub-assembly, with one end portion of said needle projecting from said structure, and said one end portion terminating in a skin puncturing tip having an opening therein, the needle being longitudinal hollow to provide a direct fluid flow pathway extending therethrough between said opening in said tip and the remainder of said needle from said one end portion, the needle having no obstruction therein along the entire length of said pathway so that direct fluid flow along the entire length of the pathway is permitted;

said support structure including a connector formation at an opposite end thereof from said needle to engage, in use of said needle assembly, with the clinical apparatus, said connector formation being integral with said support structure and having an opening therethrough in communication through said support structure with said pathway through said needle;

a guard mounted for movement relative to said sub-assembly and in a longitudinal direction of said needle between a first position in which said tip is exposed to effect said deliberate skin puncture and a second position in which said guard extends in part longitudinally beyond said tip to prevent unintended skin puncture;

said guard being carried by said sub-assembly in a captive manner to stop separation of said guard from said sub-assembly by movement from said first position in the longitudinal direction away from said second position;

a projection carried by said guard and projecting generally laterally of the longitudinal direction of said needle, said projection engaging said sub-assembly during said relative movement of said guard and said sub-assembly from said first position towards said second position;

said projection being subject to a biasing force acting between said guard and part of said sub-assembly during said relative movement of said guard and said sub-assembly;

said projection being automatically displaced in a general lateral direction in response to said relative movement of said guard and said sub-assembly to lock said guard and said sub-assembly in said second position.

6. An assembly according to claim 5 wherein said sub-assembly includes a guide for guiding said projection along said sub-assembly and throughout the extent of said relative movement of said guard and said sub-assembly from said first position to said second position. 7. An assembly according to claim 6 wherein said guide includes a groove formed in said sub-assembly. 8. An assembly according to claim 5 wherein said projection is subject to said biasing force throughout the extent of said relative movement of said guard and said sub-assembly from said first position to said second position. 9. An assembly according to claim 5 wherein said projection engages said sub-assembly in said second position of said guard and said sub-assembly. 10. An assembly according to claim 5 wherein said projection is subject to said biasing force throughout the extent of said relative movement of said guard and said sub-assembly from said first position to said second position, said projection engaging said sub-assembly in said second position of said guard and said sub-assembly. 11. For use with clinical apparatus operably applicable to a patient by way of a deliberate skin puncture, a needle assembly operable to effect said skin puncture and comprising:

an elongated support structure having first and second ends and a first direct fluid flow pathway between said ends, said first end adapted for connection and fluid communication with the clinical apparatus:

a needle fixedly mounted adjacent said second end of said structure to form therewith a sub-assembly, one end portion of said needle projecting from said structure and terminating in a skin puncturing tip having an opening therein, the needle being longitudinally hollow to provide a second direct fluid flow pathway extending therethrough between said opening in said tip and the remainder of said needle from said one end portion and in open communication with said first pathway to form a continuous direct fluid flow pathway between said support structure first end and said opening in said tip, the needle and said support structure having no obstruction therein along the entire length of said continuous pathway so that direct fluid flow along the entire length of said continuous pathway is permitted;

a guard mounted for movement relative to said sub-assembly and in a longitudinal direction of said needle between a first position in which said tin is exposed to effect said deliberate skin puncture and a second position in which said tip is enclosed by said guard to prevent unintended skin puncture;

said guard being carried by said sub-assembly in a captive manner to stop separation of said guard from said sub-assembly by movement from said first position in the longitudinal direction away from said second position;

a projection carried by one of said sub-assembly and said guard and projecting generally laterally of the longitudinal direction of said needle;

a guide slot extending along at least one side of another of said sub-assembly and said guard generally in the longitudinal direction of the needle and terminating at one end in a recess having a stop surface;

said projection engaging in said slot in said first position of said guard and said sub-assembly and engaging along said slot during said relative movement of said guard and said sub-assembly from said first position to said second position;

said projection extending into said recess upon said relative movement of said guard and said sub-assembly into said second position and engageable against said stop surface to prevent relative movement of said guard and said sub-assembly from said second position toward said first position;

said guard in said second position extending in part longitudinally beyond

said needle tip and enclosing said needle tip. 12. An assembly according to claim 11 including a lateral enlargement of said guard adjacent an end thereof remote from said needle in said second position of said guard. 13. An assembly according to claim 12 wherein said enlargement has an arcuate surface providing a finger-engaging surface. 14. An assembly according to claim 11 wherein said projection and said another of said guard and said sub-assembly are subject to a biasing force substantially throughout the extent of relative movement of said guard and said sub-assembly from said first position to said second position enabling said projection to engage said stop surface in said second position of said guard and said sub-assembly to prevent said movement from said second position toward said first position. 15. An assembly according to claim 11 wherein said guide slot is formed along said guard and said projection projects from said sub-assembly. 16. An assembly according to claim 11 wherein said guide slot is formed along said sub-assembly and said projection projects from said guard.