APPARATUS AND METHOD FOR A NEEDLE TIP COVER

摘要

A needle (10) cooperates with a tip cover (11) that coaxially fits about the needle (10) and slides axially relative thereto. A thin walled tube (15) of the needle (10) has a shank portion (12) extending from the proximal end (17) toward the distal end (16) and a tip portion (14) extending from the distal end (16) toward the proximal end (17). The tip portion (14) has a diameter ("A") that is larger than the diameter ("B") of the shank portion (12). The needle (10) includes a transition zone (13) between the shank and tip portions wherein the axial distance ("C") of the transition zone (13) is about an order of magnitude greater than the difference in the diameters of the tip and shank portions. The tip portion (14) includes a bevel (18) extending from the distal end (16) toward the transition zone (13) as a sharpened edge (19) to ease insertion. The cover (11) includes a bearing (21) and a tip protecting part (22). The bearing (21) is sized to coaxially fit about the shank portion (12) and slide axially relative thereto. The difference in the diameters of the tip and shank portions is such that the bearing (21) can not slide distally over the transition zone (13). The cover (11) is positioned on the needle (10) to locate the tip protecting part (22) over the sharpened edge (19) when the bearing (21) is at the transition zone (13). The transition zone (13) is shaped frusto conically and is located between the shank and tip portions. The frusto conical shape (20) is at angle relative to the axis ("E") of the needle (10) due to a difference in the first and second diameters thus providing a diametrical imperceptible change.