Passive safety shield

1. A safety apparatus comprising:

a needle hub;

an extensible frame connected to the needle hub, the extensible frame including a proximal segment and a distal segment, the extensible frame being resiliently biased from a retracted position to an extended position; and

an arm member extending from any one of the needle hub and segments;

wherein the arm member is configured to releasably engage any other one of the needle hub and segments to fix the extensible frame in a position between the retracted position and the extended position; and

wherein engagement of the distal segment of the extensible frame with a subject during use moves the extensible frame towards the retracted position and releases the arm member from engagement with the one of the needle hub and segments.

2. A safety apparatus as recited in claim 1 , wherein the arm extends from the needle hub.

3. A safety apparatus as recited in claim 1 , wherein a resilient member is coupled to the needle hub and at least one segment, the resilient member being configured to bias the extensible frame from a retracted position to an extended position.

4. A safety apparatus as recited in claim 1 , wherein a needle cover is connected to the distal segment.

5. A safety apparatus comprising:

a needle hub having an arm extending therefrom; and

an extensible frame connected to the needle hub, the extensible frame including a proximal segment and a distal segment, the extensible frame being resiliently biased from a retracted position to an extended position,

wherein the arm is configured to releasably engage the proximal segment to fix the extensible frame in a position between the retracted position and the extended position.

6. A safety apparatus as recited in claim 5 , wherein the extensible frame is resiliently biased via a coil spring disposed about a needle, said coil spring in an axial orientation with the needle and engaging the distal segment.

7. A safety apparatus as recited in claim 5 , wherein a needle cover is coupled to the distal segment.

8. A safety apparatus as recited in claim 7 , wherein the needle cover includes a biasing clip configured to substantially enclose a distal end of a needle.

9. A safety apparatus as recited in claim 7 , wherein the needle cover defines a transverse cavity configured for receipt of a pin, the pin being slidable within the cavity to prevent distal movement of a needle disposed within the needle cover.

10. A safety apparatus as recited in claim 5 , wherein one of the segments includes a catch tab configured to engage a needle such that the extensible frame is fixed in the extended position.

11. A safety apparatus as recited in claim 5 , wherein one of the segments defines at least one retaining pocket and the arm has a locking pin disposed adjacent a distal end thereof, the locking pin being releasably engageable with the retaining pocket.

12. A safety apparatus as recited in claim 11 , wherein the segment defines at least one retaining pocket, the retaining pocket having a flap preventing re-entry of the locking pin.

13. A method for infusing fluids to a subject, the method comprising:

providing a safety apparatus including:

a needle hub having an arm extending therefrom and configured to support a needle cannula,

an extensible frame including a proximal segment being hingedly connected to a distal segment, the extensible frame being resiliently biased from a retracted position to an extended position,

wherein the arm is configured to releasably engage the proximal segment to fix the extensible frame in a position between the retracted position and the extended position,

a needle cover extending from the distal segment and being configured to substantially enclose a distal end of the needle cannula,

and a sheath having a sheath cap and being configured to support the safety apparatus;

attaching the needle hub to a syringe;

removing the sheath cap to expose the needle cannula;

drawing liquid via the needle cannula into the syringe;

removing the sheath from the safety apparatus;

performing an infusion with the syringe and safety apparatus;

removing the needle cannula from the subject such that the needle cover automatically encloses the distal end of the needle cannula.

14. A method according to claim 13 , wherein engagement of the distal segment of the extensible frame with the subject during use moves the extensible frame towards the retracted position and releases the arm member from engagement with the proximal segment.

15. A method for infusing fluids to a subject with a single needle, the method comprising:

providing a safety apparatus including:

a needle hub configured to support a needle cannula,

an extensible frame, connected to the needle hub, including at least one segment and being resiliently biased from a retracted position to an extended position to actuate an automatic locking cover extending from the segment, and

a sheath having a sheath cap and being configured to support the safety apparatus;

attaching the needle hub to a syringe;

removing the sheath cap to expose a length of the needle cannula;

inserting the needle cannula in a vial to draw liquid, via the needle cannula, into the syringe such that the sheath prevents the automatic locking cover from actuating;

removing the sheath from the safety apparatus without actuating the automatic locking cover;

performing an infusion with the syringe and safety apparatus;

removing the needle cannula from the subject such that the locking cover automatically encloses a distal end of the needle cannula.

16. A method for infusing fluids to a subject with a single needle, the method comprising:

providing a safety apparatus including a needle cannula and a sheath having a sheath cap;

removing the sheath cap to expose a length of the needle cannula;

inserting the needle cannula in a vial to draw liquid, via the needle cannula, into a syringe;

removing the sheath from the safety apparatus;

performing an infusion with the syringe and safety apparatus; and

removing the needle cannula from the subject.