Abstract: A syringe includes a hollow barrel, a hollow plunger movable within the barrel and a needle assembly secured within and at a distal end of the barrel. The needle assembly includes a needle holder, a resilient member that biases the needle holder toward the proximal end opening of the barrel, and a retaining member releasably secured to the needle holder via a reduced material section. The retaining member maintains the needle holder at the distal end of the barrel against the bias of the resilient member. When the plunger is fully depressed within the barrel, the plunger engages the needle holder such that the retaining member is forced to break away and separate from the needle holder along the reduced material section to facilitate retraction of the needle holder and a needle secured to the needle holder into the retraction cavity disposed within the plunger.

Abstract: A syringe includes a hollow barrel, a hollow plunger movable within the barrel and a needle assembly secured within and at a distal end of the barrel. The needle assembly includes a needle holder, a resilient member that biases the needle holder toward the proximal end opening of the barrel, and a retaining member releasably secured to the needle holder via a reduced material section. The retaining member maintains the needle holder at the distal end of the barrel against the bias of the resilient member. When the plunger is fully depressed within the barrel, the plunger engages the needle holder such that the retaining member is forced to break away and separate from the needle holder along the reduced material section to facilitate retraction of the needle holder and a needle secured to the needle holder into the retraction cavity disposed within the plunger.

Abstract: A syringe includes a hollow barrel, a hollow plunger movable within the barrel and a needle assembly secured within and at a distal end of the barrel. The needle assembly includes a needle holder, a resilient member that biases the needle holder toward the proximal end opening of the barrel, and a retaining member releasably secured to the needle holder via a reduced material section. The retaining member maintains the needle holder at the distal end of the barrel against the bias of the resilient member. When the plunger is fully depressed within the barrel, the plunger engages the needle holder such that the retaining member is forced to break away and separate from the needle holder along the reduced material section to facilitate retraction of the needle holder and a needle secured to the needle holder into the retraction cavity disposed within the plunger.

Abstract: A syringe includes a hollow barrel, a hollow plunger movable within the barrel and a needle assembly secured within and at a distal end of the barrel. The needle assembly includes a needle holder, a resilient member that biases the needle holder toward the proximal end opening of the barrel, and a retaining member releasably secured to the needle holder via a reduced material section. The retaining member maintains the needle holder at the distal end of the barrel against the bias of the resilient member. When the plunger is fully depressed within the barrel, the plunger engages the needle holder such that the retaining member is forced to break away and separate from the needle holder along the reduced material section to facilitate retraction of the needle holder and a needle secured to the needle holder into the retraction cavity disposed within the plunger.

Abstract: A syringe for giving medical injections which has an internal mechanism for releasing and retracting a needle into the syringe after the injection has been given and retaining the needle and a hollow plunger inside the barrel of the syringe to reduce the risk of accidental needle sticks. The interior of the hollow plunger is initially hydraulically sealed off by a plunger front end wall from the fluid chamber of the syringe to prevent fluid from entering the interior of the hollow plunger. After the plunger has been depressed to expel fluid from the barrel, further depression of the plunger causes cutting punch type members to sever a disc shaped flange portion of a stem type needle retaining member and the plunger front end wall thereby permitting the spring to propel the needle and needle retaining member into the hollow plunger thereby retracting the needle and retaining member inside the barrel.