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 (FIG. 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, (now U.S. Pat. No. 5,601,535), .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 lengthwise, 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. 3A and 3B 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. Clinical apparatus operably applicable to a patient by way of a skin puncture, comprising:

an elongate body defining a longitudinal passageway therethrough for transfer of fluid relative to a patient, and having a first connector formation at one end thereof, said formation including a first abutment surface extending transversely of said passageway;

in combination with:

a disposable non-reusable needle assembly operable to effect said skin puncture and comprising:

a needle support housing;

a hollowed needle fixedly mounted in said housing to form with said housing a sub-assembly, with one end portion of said needle projecting from said housing;

a sheath surrounding said needle and mounted directly on said sub-assembly for relative movement in the longitudinal direction of said needle from a first position in which said needle one end portion is exposed to effect said puncture, to a second position in which said needle one end portion is enclosed within said sheath;

a locking mechanism including first and second elements, said first element being a projection from one of said housing and sheath, said second element being a stop surface defining a recess in the other of said housing and sheath, 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 housing and sheath during said relative movement, and said projection being automatically irreversibly moved into said recess alongside said stop surface in response to said bias force when said sheath is in said second position to inhibit a returning relative movement thereof towards said first position; and

a second connector formation at one end of said assembly, said second connector formation including a second abutment surface extending transversely of said needle longitudinal direction;

said apparatus and assembly being separably interconnected for use by way of said first and second connector formation, with said first and second abutment surfaces mutually engaged and effective to constrain said sheath from movement towards and around said apparatus.

2. Clinical apparatus in combination with a needle assembly, said apparatus being operably applicable to a patient by way of a deliberate skin puncture, and said needle assembly being operable to effect said skin puncture, wherein

said apparatus comprises:

an elongate body defining a longitudinal passageway therethrough for transfer of fluid relative to a patient, and having a first connector formation at one end thereof, said formation including a first abutment surface extending transversely of said passageway;

said assembly comprises:

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 second connector formation at one end of said needle assembly, said second connector formation including a second abutment surface extending traversely of said needle longitudinal direction; and

said apparatus and assembly being separably interconnected for use by way of said first and second connector formations, with said apparatus held outside said needle, and with said first and second abutment surfaces mutually engaged and effective to constrain said guard from movement towards and around said apparatus.

3. Clinical apparatus in combination with a needle assembly, said combination being operably applicable to a patient by way of a deliberate skin puncture with said needle assembly being operable to effect said skin puncture wherein:

said apparatus comprises an elongate body defining a longitudinal passageway therethrough for transfer of fluid relative to a patient, and having a connector formation at one end thereof including a tapered surface;

said assembly 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 longitudinally 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 the connector formation of said elongate body of the clinical apparatus, said connector formation of said support structure being integral with said support structure and having an opening therethrough in communication through said support structure with said pathway through said needle and in communication with said longitudinal passage of said elongate body;

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;

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.

4. A combination according to claim 3 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.5. A combination according to claim 4 wherein said guide includes a groove formed in said sub-assembly.6. A combination according to claim 3 wherein said connector formation of said support structure including a tapered surface;

said elongate body and said needle assembly being separately interconnected for use by way of mutual engagement of said tapered surfaces.7. A combination according to claim 6 wherein each said connector formation includes generally frustoconical tapered surfaces.8. A combination according to claim 3 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. A combination according to claim 3 wherein said projection engages said sub-assembly in said second position of said guard and said sub-assembly.10. A combination according to claim 3 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. A combination according to claim 3 wherein said apparatus is a syringe.12. Clinical apparatus operably applicable to a patient by way of a skin puncture, comprising:

an elongate body defining a longitudinal passageway therethrough for transfer of fluid relative to a patient in combination with:

a disposable non-reusable needle assembly operable to effect said skin puncture and comprising:

a needle support housing;

a needle fixedly mounted in said housing to form with said housing a sub-assembly, with one end portion of said needle projecting from said housing;

said needle and said housing being hollowed in the longitudinal direction of said needle to provide a fluid flow pathway extending wholly therethrough, and said pathway having no obstruction therein along its entire length to direct fluid flow therethrough;

a sheath surrounding said needle and mounted directly on said sub-assembly for relative movement in the longitudinal direction of said needle from a first position in which said needle one end portion is exposed to effect said puncture, to a second position in which said needle one end portion is enclosed within said sheath;

a locking mechanism including first and second elements, said first element being a projection from one of said housing and sheath, said second element being a stop surface defining a recess in the other of said housing and sheath, 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 housing and sheath during said relative movement, and said projection being automatically irreversibly moved into said recess alongside said stop surface in response to said bias force when said sheath is in said second position to inhibit a returning relative movement thereof towards said first position; and

said apparatus and assembly having respective connector formations for separable interconnection to communicate said passageway of said apparatus with said pathway of said assembly for fluid flow

therebetween.13. Apparatus according to claim 12 wherein said connector formations include respective tapered surfaces for mutual engagement.14. Apparatus according to claim 12 wherein said projection is from said housing, said recess is formed in said sheath, and said sheath includes a guide for guiding said projection throughout the extent of said relative movement from said first position to said second position.