Method and apparatus for shielding the tip of a catheter introducer needle

A medical needle assembly includes: a needle cannula having a body and a tip, the tip is disposed at a distal end of the cannula; a part fixed to the needle cannula body; a shield slidingly mounted to the needle for movement between a proximal position to a distal position, wherein, the shield includes a shield body having a central chamber, a distal end and a proximal end; a plate secured to theproximal end of the shield body and defining an aperture; wherein, when the shield is at the proximal end, the introducer needle is partly in the central chamber and passes through the hole of the plate; the size of the hole is defined that the needle body can pass through but the part can not; and a bending part which has a first end, a second end, and a thickness, wherein the first end is fixedin the shield body and in the central chamber; the second end of the bending part extends radially inward to the central chamber; when the shield is at proximal end, the needle body can press the bending part into a groove for