US Patent 7559919 Needle shield

A needle shield is removably mountable to a syringe to protect a user from inadvertent needle pricks and limit contamination of a needle of the syringe. The needle shield includes a plug having an external surface and a shell having an inner surface defining a cavity therein. The plug is positioned within the cavity and a portion of the external surface of the plug is in contact with the inner surface of the shell at a contact area. The plug is non-removably bonded to the shell in the contact area by melting a portion of the shell and the plug in the contact area through application of radiation energy. A securing ring may alternatively be fixed to the shell through the application of radiation energy to secure a shoulder of the plug between the ring and a rib of the shell. The radiation energy is preferably applied by laser welding.