Safety medical syringe with retractable needle

A syringe comprising:

• a hollow barrel having a proximal opening, a distal opening and a fluid chamber defined therebetween, the barrel having an interior surface proximate the distal opening;
• a hollow plunger having a cavity and extending into the barrel via the proximal end opening and axially movable within the barrel toward and away from the distal end opening;
• a needle assembly configured to be selectively secured at least partially within and located proximate a distal end of the barrel, the needle assembly comprising a needle holder, a resilient member biasing the needle holder toward the barrel proximal end opening, and a retaining member releasably secured to the needle holder via a reduced material section, further comprising:
• a needle connector secured to a needle and configured to releasably secure the needle to the needle holder, wherein the needle connector and the needle holder include corresponding engaging portions comprising at least one protrusion and a corresponding groove that engage with each other when the needle connector is secured to the needle holder.

A syringe comprising:

• a hollow barrel having a proximal opening, a distal opening and a fluid chamber defined therebetween, the barrel having an interior surface proximate the distal opening;
• a hollow plunger having a plunger cavity and extending into the barrel via the proximal end opening and axially movable within the barrel toward and away from the distal end opening;
• a needle assembly configured to be selectively secured at least partially within and located proximate a distal end of the barrel, the needle assembly comprising a needle holder, a resilient member biasing the needle holder toward the barrel proximal end opening, and a retaining member releasably secured to the needle holder via a reduced material section;
• wherein the barrel comprises a retention member extending inwardly from the interior surface configured to allow the needle assembly to be positioned therepast from the barrel proximal opening, the retention member configured to secure the needle assembly in the axial direction when the plunger is advanced to engage the needle assembly and until the needle holder is retracted into the plunger cavity.

A method of utilizing a syringe, comprising:

• a hollow barrel having a proximal opening, a distal opening and a fluid chamber defined therebetween, the barrel having an interior surface proximate the distal opening;
• a hollow plunger having a plunger cavity and extending into the barrel via the proximal end opening and axially movable within the barrel toward and away from the distal end opening;
• a needle assembly configured to be selectively secured at least partially within and located proximate a distal end of the barrel, the needle assembly comprising a needle holder, a resilient member biasing the needle holder toward the barrel proximal end opening, and a retaining member releasably secured to the needle holder via a reduced material section;
• wherein the barrel comprises a retention member extending inwardly from the interior surface configured to allow the needle assembly to be positioned therepast from the barrel proximal opening;
• comprising the steps of:
• inserting the needle assembly into the barrel proximal opening and advancing past the barrel retention member such that it locks in place in the axially direction;
• advancing the plunger to engage the locked needle assembly until the reduced material section is ruptured and the needle holder is retracted by the resilient member into the plunger cavity.

A single use syringe comprising:

• a hollow syringe body including a longitudinal passageway with an open proximal end and an open distal end;
• a plunger including a distal end that extends into the syringe body via the open proximal end of the syringe body;
• and
• a needle holder that is disposed at least partially within and proximate the distal end of the syringe body, a needle that is removably or fixedly attached to the needle holder, a spring in the syringe body distal end that is biased to project the needle holder through the distal end of the plunger and into the plunger, the needle holder comprising an inner part and an outer part, the inner part containing the needle, the outer part including an outer peripheral portion that engages with a wall of the longitudinal passageway, the inner part being configured to break away from the outer part at a break away section located between the inner part and outer part, the outer part containing a raised portion directed toward the distal end of the plunger, the raised portion extending only partially around the inner part, and the raised portion being configured to provide an initial contact area for the plunger with the outer part of the needle holder so as to reduce a force required to break the inner part from the outer part.

A syringe comprising:

• a hollow barrel including an opening at a proximal end of the barrel, an opening at a distal end of the barrel and a fluid chamber disposed within the barrel;
• a hollow plunger having a plunger cavity and extending into the barrel via the proximal end opening and axially movable within the barrel toward and away from the distal end opening;
• and
• a needle assembly secured at least partially within and located proximate the distal end of the barrel, the needle assembly comprising a needle holder, a resilient member biasing the needle holder toward the proximal end opening of the barrel, and a retaining member comprising a retainer ring disposed about a proximal end of the needle holder and releasably secured to the needle holder via a reduced material section, wherein the needle holder is configured to fixedly or releasably secure a needle to the needle holder so as to permit the needle to extend through the distal end opening of the barrel, and the reduced material section of the retaining member comprises at least one scored section defined between the retainer ring and the needle holder such that the retaining member and needle holder are configured as a single, integral piece prior to separation of the retaining member from the needle holder;
• wherein:
• the retainer ring includes at least one protrusion that extends from a surface of the retainer ring toward the plunger, the at least one protrusion is disposed between a peripheral edge of the retainer ring and the at least one scored section, and the plunger and the at least one protrusion are further configured to initiate a progressive breaking away of the retainer ring from the needle holder along the at least one scored section upon engagement of the at least one protrusion of the retainer ring with the plunger distal end in combination with movement of the plunger toward the barrel distal end, such that upon completion of the break the needle holder retracts into the plunger retraction cavity.