Importance

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Abstract

This dripless automatic syringe for dispensing fluids has a barrel for containing the fluid, a nozzle for discharging the fluid, and a housing to which the barrel is attached. A piston rod in the housing carries a rigid sealed piston head in the barrel for pushing out the fluid. Behind the piston head a normally unflexed elastic disc in the housing. The disc flexes when the piston rod moves forwardly under a driving force. The disc unflexes to retract the piston rod and piston head slightly when the driving force stops to create a suction which draws fluid back into the nozzle and thereby prevents dripping. The disc has an integral nipple which frictionally grips the rod to hold it in place, when the driving force ceases. The nipple permits axial rearward movement of the piston rod by an externally applied force for filling the barrel with fluid.

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First Claim