Safety syringe with releasable anti-rotation retractable needle adapter

A syringe comprising:

• an axially elongated barrel having a hollow interior;
• an adapter carried by said barrel adjacent a distal end thereof and removable therefrom in response to rotation relative to and about the axis of the barrel, the adapter having a passage for providing fluid communication with the interior of the barrel;
• a plunger axially movable in said barrel between positions axially spaced from said adapter and engaging said adapter;
• an adapter-engagement structure disposed adjacent a first end of the plunger and engageable with mating engagement structure on the adapter for enabling rotation of the adapter and distal end of the barrel relative to one another to cause the adapter to part from the distal end of the barrel;
• means cooperable between the adapter and the barrel for preventing relative rotation of the adapter and the distal end of the barrel;
• connective surfaces engageable between said plunger and adapter enabling withdrawal of said adapter, when parted from the distal end of the barrel, into the interior of the barrel upon joint axial movement of said plunger and said adapter in a direction away from the distal end of the barrel;
• and
• means cooperable between the plunger and the adapter for disabling said preventing means thereby enabling relative rotation of the adapter and the distal end of the barrel and withdrawal of the adapter, when parted from the distal end of the barrel, into the interior of the barrel.

A syringe comprising:

• an axially elongated barrel having a hollow interior;
• an adapter carried by said barrel adjacent a distal end thereof and removable therefrom in response to rotation relative to and about the axis of the barrel, the adapter having a passage for providing fluid communication with the interior of the barrel;
• a plunger axially movable in said barrel between positions axially spaced from said adapter and engaging said adapter;
• an adapter-engagement structure disposed adjacent a first end of the plunger and engageable with mating engagement structure on the adapter for enabling rotation of the adapter and distal end of the barrel relative to one another to cause the adapter to part from the distal end of the barrel;
• first elements interengageable between the adapter and the barrel for preventing relative rotation of the adapter and the distal end of the barrel;
• connective surfaces engageable between said plunger and adapter enabling withdrawal of said adapter, when parted from the distal end of the barrel, into the interior of the barrel upon joint axial movement of said plunger and said adapter in a direction away from the distal end of the barrel;
• and
• elements cooperable between the plunger and the adapter to disable said interengageable elements from preventing relative rotation of the adapter and the distal end of the barrel thereby enabling relative rotation of the adapter and the distal end of the barrel and withdrawal of the adapter, when parted from the distal end of the barrel, into the interior of the barrel.