Patent ID: 8728036

Claim:
An anesthetic compound needle comprising: an outer needle; an inner needle; a tubular adaptor; a tubular inner needle proximal end portion at a proximal end of said inner needle and having a front portion attached to a rear end portion of said adaptor; a tubular outer needle proximal end portion at a proximal end of said outer needle and inserted through an opening in a distal end of said adaptor, and a distal end of said inner needle protruding from a distal end of said outer needle; a plurality of parallel peripherally-extending grooves formed along an axial direction on a lower outer surface of said outer needle proximal end portion; and a restricting plate having an insertion hole through which said outer needle proximal end portion is inserted, said restricting plate being inserted into said adaptor through an opening in an upper surface of said adaptor, said adaptor having a plate spring portion for urging said restricting plate upward when said restricting plate is pushed downward and for pushing said restricting plate upward when the downward pushing force is released, said plate spring portion being formed of a cutout portion in a lower surface of said adaptor; wherein said restricting plate has a protrusion formed on a lower surface of said insertion hole, said protrusion protruding upward so as to engage one of said grooves on said lower outer surface of said outer needle proximal end portion; wherein said adaptor, said outer needle proximal end portion, and said restricting plate are configured so that, when said restricting plate is pushed downward, said grooves on said outer needle proximal end portion and said protrusion of said restricting plate are disengaged from each other so that said inner needle is in an unlocked state to allow said inner needle to be advanced or retracted relative to said outer needle; and wherein said adaptor, said outer needle proximal end portion, and said restricting plate are configured so that, when the downward pushing force is released, said restricting plate is pushed upwardly by said plate spring portion and said protrusion of said restricting plate engages one of said grooves on said outer needle proximal end portion so that said inner needle is in a locked state to prevent said inner needle from advancing or retracting relative to said outer needle.