Patent ID: 8491468

Claim:
A suction syringe comprising: a tubular body in which a suction opening is formed; a piston body comprising a piston portion which reciprocates in close contact with a side surface in the tubular body and whose reciprocating movement is used to suck fluid from the suction opening into a tubular body suction chamber; a shaft portion which supports the piston portion; a pressing portion which is provided on a rear side of the shaft portion; a shaft portion vent passage formed in the shaft portion; a first vent hole formed in the pressing portion communicating with the vent passage; and a second vent hole in a side of the shaft portion; and a biasing member which is disposed between the pressing portion of the piston body and the tubular body, and returns the piston body to an original position after the piston body has been moved forward, wherein moving the piston body forward causes fluid to be sucked from the suction opening into the tubular body, and fluid inside the tubular body is discharged outside through the shaft portion vent passage when the piston body is moved backward, wherein a suction opening of the tubular body is pipe-connected to a fluid storage tank which is pipe-connected to a suction port of an endoscope, and the suction syringe is used as a suction device for the endoscope, wherein the piston portion divides the tubular body into a front chamber and a rear chamber, wherein a third vent hole is formed on the tubular body at a front end of the tubular body so as to communicate with the front chamber, wherein the second vent hole and the suction opening communicate with the rear chamber, and wherein fluid is sucked through the suction opening into the rear chamber by moving the piston body forward with the first vent hole blocked.