PROBLEM TO BE SOLVED: To eliminate the possibility that a driving mechanism and portions adjacent thereto will be broken or damaged.SOLUTION: The medical injector has a housing 2 into which a syringe 1 having an outer cylinder 5 and a plunger 6 is to be detachably loaded, and a manual driving mechanism 3 provided in the housing 2 and sliding the plunger 6 of the syringe 1 axially forward. The driving mechanism 3 has a rack 46 sliding the plunger 6 of the syringe 1, a pinion 39 engaging with the rack 46, a driven shaft 40 relatively nonrotatably provided with the pinion 39, a driving shaft 42 separated axially from the driven shaft 40, a torque limiter 41 relatively nonrotatably engaging the axial ends with the driven shaft 40 and the driving shaft 42, and a manual rotary handle 43 relatively nonrotatably provided at the driving shaft 42.COPYRIGHT: (C)2010,JPO&INPIT【課題】駆動機構やこれに隣接する部分等が破損、損傷する惧れをなくす。【解決手段】外筒5とプランジャ6を有するシリンジ1が着脱自在に装填されるハウジング2と、ハウジング2に備えられ且つシリンジ1のプランジャ6を軸心方向前方に摺動させる手動式駆動機構3を有する。駆動機構3は、シリンジ1のプランジャ6を摺動させるラック46と、ラック46と噛合するピニオン39と、ピニオン39が相対回転不能に備えられた従動軸40と、従動軸40から軸心方向に離間した駆動軸42と、従動軸40と駆動軸42に軸心方向各端部が相対回転不能に係合されたトルクリミッタ41と、駆動軸42に相対回転不能に備えられた手動式回転ハンドル43を有する。【選択図】 図12
