Patent ID: 6962273

Claim:
A liquid-dispensing structure comprising: an outer cylinder to be filled with a liquid, said outer cylinder having a one-way valve at its lower end to allow a liquid to flow into the outer cylinder; a hollow piston provided inside the outer cylinder, said piston having a pair of liquid-tight portions formed around its outer circumferential surface, each of which portions liquid-tightly contacts an inner circumferential surface of the outer cylinder, said pair of liquid-tight portions being arranged in positions apart in an axial direction of the outer cylinder, said liquid-tight portions being circular convex portions, wherein one of the pair of liquid-tight portions is provided at an upper end of the piston, and the other of the pair of liquid-tight portions is provided at a lower end of the piston; and an inner cylinder for dispensing the liquid, which reciprocates inside the outer cylinder in an axial direction of the inner cylinder which is co-axial with the outer cylinder, said inner cylinder having a piston-sliding area where when the inner cylinder moves, the piston moves liquid-tightly with respect to the inner cylinder between a lower position and an upper position in the axial direction of the inner cylinder, said inner cylinder having an opening which is closed when the piston is at the lower position and which is opened when the piston is at the upper position wherein the liquid inside the outer cylinder flows into an inside of the inner cylinder through the opening.