Safety catheter and needle assembly

1. An IV catheter and safety needle assembly comprising:

a catheter assembly including a catheter hub defining a receptacle and a tubular catheter extending distally from and in fluid communication with the receptacle, the catheter hub including one or more protrusions extending from an inner wall of the catheter hub into the receptacle;

a needle assembly including a needle hub defining a chamber and a needle in fluid communication with the chamber, the needle including a sharpened distal tip and an enlarged diameter portion disposed proximally of the distal tip, the needle being dimensioned to extend through the catheter assembly such that the sharpened tip extends from a distal end of the tubular catheter; and

a needle guard supported within the receptacle and having a proximal end positioned adjacent to the one or more protrusions and a distal end having an inner diameter which is smaller than the enlarged diameter portion of the needle, wherein upon withdrawal of the needle from the catheter assembly, the enlarged diameter portion of the needle is positioned to engage the distal end of the needle guard to move the needle guard into the one or more protrusions and effect an inversion of the needle guard about the sharpened tip of the needle.

2. The IV catheter and safety needle assembly according to claim 1 , wherein the enlarged diameter portion of the needle defines a crimp.

3. The IV catheter and safety needle assembly according to claim 1 wherein the enlarged diameter portion of the needle includes a protuberance formed on the needle.

4. The IV catheter and safety needle assembly according to claim 1 , wherein the needle guard defines a conical throughbore having a diameter at a proximal end which is larger than the inner diameter at the distal end.

5. The IV catheter and safety needle assembly according to claim 4 , wherein the needle guard has a conical configuration.

6. The IV catheter and safety needle assembly according to claim 1 , wherein the needle hub defines a flashback chamber.

7. The IV catheter and safety needle assembly according to claim 6 , wherein the needle hub is formed from a transparent material.

8. The IV catheter assembly comprising:

a catheter assembly including a catheter hub defining a receptacle and a tubular catheter extending distally from and in fluid communication with the receptacle, the catheter hub including one or more protrusions extending from an inner wall of the catheter hub into the receptacle;

a needle assembly including a needle hub defining a chamber and a needle in fluid communication with the chamber, the needle including a sharpened distal tip and an enlarged diameter portion disposed proximally of the distal tip, the needle being dimensioned to extend through the catheter assembly such that the sharpened tip extends from a distal end of the tubular catheter; and

a needle guard supported within the receptacle and having a proximal end positioned adjacent to the one or more protrusions and a distal end having an inner diameter which is smaller than the enlarged diameter portion of the needle, wherein upon withdrawal of the needle from the catheter assembly, the enlarged diameter portion of the needle is positioned to engage the distal end of the needle guard to move the needle guard into the one or more protrusions and effect an inversion of the needle guard about the sharpened tip of the needle;

wherein the needle guard includes a cutout formed in an outer surface of the needle guard, the cutout being positioned and configured to receive the enlarged diameter portion of the needle upon inversion of the needle guard.

9. The IV catheter and safety needle assembly according to claim 8 , wherein the enlarged diameter portion of the needle is configured to resist removal of the enlarged diameter portion from the cutout.

10. The IV catheter and safety needle assembly according to claim 1 , wherein the enlarged diameter portion of the needle is dimensioned to frictionally engage the inner diameter of the needle guard after inversion of the needle to retain the needle guard on the tip of the needle.

11. The IV catheter and safety needle assembly according to claim 8 , wherein the enlarged diameter portion of the needle defines a crimp.

12. The IV catheter and safety needle assembly according to claim 8 wherein the enlarged diameter portion of the needle includes a protuberance formed on the needle.

13. The IV catheter and safety needle assembly according to claim 8 , wherein the needle guard defines a conical throughbore having a diameter at a proximal end which is larger than the inner diameter at the distal end.

14. The IV catheter and safety needle assembly according to claim 13 , wherein the needle guard has a conical configuration.

15. The IV catheter and safety needle assembly according to claim 8 , wherein the needle hub defines a flashback chamber.

16. The IV catheter and safety needle assembly according to claim 15 , wherein the needle hub is formed from a transparent material.

17. The IV catheter and safety needle assembly according to claim 8 , wherein the enlarged diameter portion of the needle is dimensioned to frictionally engage the inner diameter of the needle guard after inversion of the needle to retain the needle guard on the tip of the needle.