PROBLEM TO BE SOLVED: To provide an inexpensive syringe 1 preventing an erroneous puncture accident.SOLUTION: An outer hub 5 is mounted on the distal end of the barrel 2 of the syringe 1, an inner hub 7 on which a cannula 6 is mounted is provided in the outer hub 5 so as to be moved back and forth, and a spring 8 is elastically equipped between the inner hub 7 and the outer hub 5. A through-hole is formed from the outer peripheral surface to the inner peripheral surface on the outer hub 5, the engagement pin of an engagement member is inserted into the through-hole, the engagement pin is mutually engaged with a recessed part formed on the inner hub 7 and the inner hub 7 is held at the position of being moved forward against the energizing force of the spring 8. After using the syringe 1, by pulling out the engagement member 9, the engagement pin and the inner hub 7 are disengaged, and the inner hub 7 is moved back by the energizing force of the spring 8 and is housed inside the barrel 2 together with the cannula 6.COPYRIGHT: (C)2008,JPO&INPIT【解決手段】注射器1のバレル2の先端には外ハブ5が装着されており、該外ハブ5にはカヌラ6の装着された内ハブ7が進退動可能に設けられるとともに、内ハブ7と外ハブ5との間にはばね8が弾装されている。外ハブ5には外周面から内周面に貫通孔が形成されており、該貫通孔には係合部材の係合ピンが挿入され、該係合ピンは内ハブ7に形成された凹部と相互に係合して、内ハブ7をばね8の付勢力に抗して前進位置に保持している。注射器1の使用後には、上記係合部材9を引き抜くことで、上記係合ピンと内ハブ7との係合が解除され、内ハブ7はばね8の付勢力により後退し、カヌラ6ごとバレル2内に収容されることとなる。【効果】誤穿刺事故を防止することができ、かつ安価な注射器1を提供する。【選択図】図3
