US Patent 7452348 Transfer needle assembly

A transfer needle assembly including a cap-like outside guide member; a tubular inside guide member; and a puncture member. The puncture member has a tip fitting portion at a proximal end and a puncture needle at a distal end. The inside guide member can slide along an inner wall of a skirt portion of the outside guide member from a position where a distal end of the needle is receded in the inside guide member, to a position where the distal end of the needle projects outside of the inside guide member. At the position where the distal end of the needle is receded in the inside guide member, the outside guide member and the inside guide member are engaged so as to be incapable of sliding, with the engagement being releasable by inserting a mouth portion of a vial into the inside guide member.