Abstract: A medical syringe has a needle shoot back mechanism which can be triggered to shoot the used needle back into the safety of the syringe body and is of a special design to allow the needle to be replaced without affecting the efficiency of the shoot back mechanism. A rotatable cover member is also available which is relatively large and which can be more easily gripped and turned to remove the needle from the syringe.

Abstract: A single use syringe including shoot back, or retraction, mechanism for biasing a needle, retained in needle holder, back into the interior of the syringe body after use. The needle holder is urged, by a spring in the front of the syringe body, to pass through a piercable seal formed in the front fact of the piston. The needle holder comprises an inner part containing the needle, an outer part engaging the interior wall of the syringe, and a frangible portion joining the inner and outer parts. A raised portion, or bump, is formed partially about the outer part of the needle holder, facing the seal in the piston. The raised portion provides an initial contact area with the plunger, to reduce the force required to break the frangible portion and trigger the shoot-back mechanism. The raised portion may consist of an uppermost portion for contact with the plunger, and a shoulder portion adjacent the uppermost portion to reduce dead space.

Abstract: A positive pressure one way medical valve contains an inlet (10), outlet (11), an internal flow path between the inlet and the outlet and a plunger (12) movable between a retraced sealing position, where backflow is reduced or prevented and an extended open position, where fluid can flow from the inlet to the outlet. The plunger is moved from the retraced to the extended position by insertion of a tip onto the inlet (10). A variable volume chamber (23) is defined partially by an elastomeric member (14) that is stretched, when plunger is in the extended position and reduced, when the plunger is in the retraced position so to increase or decrease the volume of the chamber respectively. A valve (50), which is movable between open and closed positions by the presence or absence of fluid passing through the inlet, immediately seals the flow pathway before the plunger is retraced.

Abstract: A one-way valve assembly can be fitted to the end of a syringe to allow fluid to flow from the syringe and into a body cavity but to prevent backflow. The valve assembly is opened by insertion of the luer tip of the syringe into the assembly inlet. The valve has an internal elastic member that forms a variable volume internal chamber. This chamber expands upon insertion of the luer tip into the inlet and shrinks when the luer tip is removed from the assembly. The shrinking action creates a positive pressure in the valve assembly to prevent backflow.

Abstract: A single use syringe uses a “pinching” action between a specially designed plunger and a specially designed needle holder to shoot the needle back into the syringe body upon completion of the piston stroke. The needle is not biased by a helical spring and the syringe remains in an unbiased condition until the plunger is pushed against the needle holder that creates the pinching action to shoot the needle back into the syringe body.

Abstract: A medical syringe container comprising a housing, an outlet through which a new syringe can be removed from the housing, an inlet through which a syringe can be replaced into the housing, and holding means to prevent a second syringe from being removed from the housing until a used syringe has been replaced into the housing. The container is particularly useful with needle exchange programs.

Abstract: A single use syringe has a needle which is biased back into the barrel but which is prevented from doing so by a holding means which has an outer part and an inner part which are connected together by a frangible portion. The needle is held by the inner part. When the plunger is pushed towards the front of the barrel, it contacts the outer part and pushes it forwardly which stretches the frangible portion until it bursts. When the frangible portion breaks, the inner portion containing the needle is released and can shoot back into a hollow portion in the plunger through the frangible portion of the plunger head.

Abstract: A one-way valve assembly can be fitted to the end of a syringe to allow fluid to flow from the syringe and into a body cavity but to prevent backflow. The valve assembly is opened by insertion of the luer tip of the syringe into the assembly inlet. The valve has an internal elastic member that forms a variable volume internal chamber. This chamber expands upon insertion of the luer tip into the inlet and shrinks when the luer tip is removed from the assembly. The shrinking action creates a positive pressure in the valve assembly to prevent backflow.