Patent ID: 8603041

Claim:
A needle assembly comprising: a needle comprising a longitudinal axis, a proximal end, a sharp distal end and an outer surface; a needle shield assembly comprising: a first housing having an outer wall and an internal lumen, the internal lumen having a longitudinal axis and being sized such that the first housing is slidable longitudinally along the outer surface of the needle, the first housing being provided with an opening therein, the opening forming a carrier for carrying a needle blocking object, wherein the opening extends from the outer wall to the internal lumen; the needle blocking object carried by the carrier, wherein the needle blocking object is a ball; and a spring positioned such that in a non-shielding position, the spring biases the needle blocking object towards the longitudinal axis of the needle, wherein in the non-shielding position the carrier prevents complete circumferential movement within the carrier of the needle blocking object about the longitudinal axis of the needle; wherein in a shielding position, the carrier limits radial movement of the needle blocking object toward the longitudinal axis of the needle, the needle blocking object lies at least partially in the internal lumen, thereby blocking emergence of the sharp distal end from the needle shield assembly, and the sharp distal end of the needle exerts a force on the needle blocking object, the force comprising a first component in a substantially distal direction and a second component in a substantially radial direction; and a restraint associated with the needle shield assembly for preventing movement of the needle shield assembly off the sharp distal end of the needle.