PROBLEM TO BE SOLVED: To provide an infusion pump cassette including a changeover structure between a free flow state and a locked state and hardly causing malfunction.SOLUTION: The infusion pump cassette includes: a body member with an internal space that receives a tube, circulates it along an inner wall surface 203a and extends it to the outside a ring member 220 installed in the internal space toward an inner wall surface 203a at a position for clamping a tube 50 and an eccentric member 210 that freely moves to an infusion position and an opening position and, at the infusion position, presses the ring member 220 to crush the tube 50. The eccentric member 210 includes an eccentric pin 211, and a plunger 212 that, when the eccentric member 210 is at the infusion position, presses the ring member 220 from the inside of the annulus. The ring member 220 includes a large-diameter part 221 that receives the plunger 212 when the eccentric member 210 is at the opening position and escapes from the pressure by the eccentric member 210, where a lower cover 201 supports the large diameter parts 221 to prevent the annular member from moving in the center line direction.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2017,JPO&INPIT【課題】フリーフロー状態とロック状態との切替構造を備え、かつ作動不良の生じ難い輸液ポンプ用カセットを提供する。 【解決手段】チューブを受け入れ内壁面203aに沿わせて周回させて外部に延出させる内部空間を有する本体部材と、内部空間の、内壁面203aとの間にチューブ50を挟む位置に装入されたリング部材220と、輸液位置と開放位置とに移動自在し、輸液位置において、リング部材220を押圧してチューブ50を押し潰す偏芯部材210とを備え、偏芯部材210が、偏芯ピン211と、偏芯部材210が輸液位置にあるときにリング部材220を環の内側から押圧するプランジャ212とを有し、リング部材220が、偏芯部材210が開放位置にあるときのプランジャ212を受け入れて、偏芯部材210による押圧を免れる太径部221を有し、下カバー201が、太径部221を支持して、円環部材の、中心線方向への移動を阻止する。【選択図】図3
