Patent ID: 7261704

Claim:
A syringe comprising: an outer tube, a gasket slidable in said outer tube, a pusher inserted through an opening of a base end of said outer tube and operable for moving said gasket, a stopper disposed on said pusher to be slidable along the longitudinal direction of said pusher, fixing means for selecting and fixing the position of said stopper on said pusher, an operating portion provided in said stopper for performing a pressing operation, a traction operation or a pinching operation, wherein the position of said stopper on said pusher can be regulated by releasing the fixation by said fixing means through an operation at said operating portion, wherein the depth of insertion of said pusher into said outer tube is restricted by abutment of said stopper on a portion of said outer tube, wherein said fixing means is returned to a fixation state by elasticity when the operation on said operating portion is released, wherein said fixing means comprises a rack provided on said pusher and including a plurality of engaging recessed portions or engaging projected portions provided at a predetermined interval along the longitudinal direction of said pusher, and an engaging portion provided on said stopper to be displaceable between a state of being engaged with said rack and a state of being retracted from said rack, said engaging portion is normally engaged with said rack and is retracted from said rack by an operation at said operating portion, wherein said fixing means comprises a pressing portion operated in conjunction with said operating portion to be displaced between a first position for pressing said engaging portion to be engaged with said rack and a second position for releasing the pressing, and biasing means biasing said pressing portion to bring into said first position, and said fixing means is normally in such a state that said pressing portion is located in said first position and said engaging portion is engaged with said rack to fix said stopper, said fixing means being so operated that, when said operating portion is operated, said pressing portion is moved to said second position, whereby said engaging portion is retracted from said rack and a fixation of said stopper is released, and when the operation on said operating portion is released, said fixing means is returned into the state for fixation of said stopper by the biasing force of said biasing means.