Blood sampling assembly with a retractable needle

A method of retracting a needle from a cylinder, the needle having an end for insertion into a patient such that a vial is pressed over an opposed end of the needle to obtain a blood sample, the method comprising:

• providing a cylinder having a needle end and an opposed extractor end;
• providing circumferentially spaced needle seat tabs and needle seat slots each between spaced needle seat tabs on the cylinder;
• providing a stopper tab stop on the cylinder;
• engaging circumferentially spaced cylinder tabs on a needle seat each with a respective needle seat tab to support the needle seat on the cylinder;
• providing cylinder slots each between the spaced cylinder tabs on the needle seat;
• providing a cap stop on the needle seat;
• providing a closed end tube containing a vacuum and a stopper in sealed engagement with the tube and axially movable between an initial position and a needle retracted position;
• axially securing a stopper tab to the stopper;
• engaging a retainer tab on a stopper retainer with the stopper tab when the stopper tab is in a retaining position;
• providing an end cap rotatable with the tube, the end cap including a needle seat stop;
• inserting the tube at least partially within the extractor end of the cylinder such that the opposed end of the needle is within the stopper;
• engaging the stopper tab stop on the cylinder with the stopper tab to prevent rotation of the stopper tab;
• and
• rotating the tube, the end cap and the stopper retainer from a retaining position for retaining the stopper in the initial position to a release position for releasing the stopper to move to the retracted position, such that a slot in the stopper retainer is circumferentially aligned with the stopper tab when the stopper retainer is in the release position and the cylinder slots on the needle seat are each circumferentially aligned with a respective needle seat tab on the cylinder to release the needle seat and the stopper so that the stopper may move to the needle retracted position within the tube by the vacuum.

A blood sampling assembly with a retractable needle for use to obtain a blood sample within a vial, such that an end of the needle is adapted to be inserted into a patient and an opposed end of the needle is sealed with the vial to obtain the blood sample, the blood sampling assembly comprising:

• a hollow cylinder having a needle end and an opposed extractor end, the cylinder including circumferentially spaced needle seat tabs and needle seat slots each between spaced needle seat tabs, the cylinder further including a stopper tab stop;
• a needle seat for supporting the needle on the cylinder, the needle seat including circumferentially spaced cylinder tabs each in engagement with a respective needle seat tab to temporarily fix the needle seat to the cylinder, the needle seat including cylinder slots each between spaced cylinder tabs and circumferentially aligned with a respective needle seat tab to release the needle seat and the needle from the cylinder, the needle seat further including a cap stop;
• and
• an extractor assembly for positioning at least partially within the extractor end of the cylinder, the extractor assembly including a closed end tube containing a vacuum, a stopper in sealed engagement with an interior surface of the tube and axially movable between an initial position and a needle retracted position, the stopper receiving therein the opposed end of the needle, a stopper tab axially secured to the stopper, a stopper positioner in engagement with both the stopper tab stop on the cylinder and the stopper tab for preventing rotation of the stopper tab during rotation of the tube, an annular stopper retainer including a throughbore and rotatable with the tube between a retaining position for temporarily fixing the stopper in the initial position and a release position for releasing the stopper to move to the needle retracted position, a retainer tab on the annular stopper retainer in engagement with the stopper tab when the stopper retainer is in the retaining position and a slot in circumferential alignment with the stopper tab when the stopper retainer is in the release position, and an annular end cap rotatable with the tube and including a throughbore and a needle seat stop for engagement with the cap stop, such that rotation of the tube rotates the end cap, the stopper retainer, and the needle seat relative to the cylinder to release the needle seat and the stopper and the stopper is moved to the needle retracted position by the vacuum within the tube.