Patent ID: 8062320
Filing Date: 2011-11-22
Classification: A61B

Abstract:
1. A puncture device comprising: a housing having an opening at a front end, and a plunger retained in the housing, slidably in forward and backward axial directions of the housing, said plunger detachably holding a puncture needle; and a tension spring biasing the plunger in its forward and backward directions; wherein a lever is rotatably connected to the plunger and rotatable within a predetermined range; a front end of the tension spring is fixed to a first tension spring fixing chip that is fixed in the housing; a rear end of the tension spring is latched by a second tension spring fixing part that is on the rotatable lever; said second tension spring fixing part is movable backward in conjunction with backward movement of the plunger, thereby expanding the tension spring in an axial direction of the puncture device; said tension spring urging the plunger toward the front end of the housing via the second tension spring fixing part and the lever, by a restorative force caused by expansion of the tension spring in its axial direction; whereby when the plunger moves toward the front end of the housing due to the spring urging toward the front end, a peripheral edge portion of the rotatable lever, which is located between the axis of rotation of the lever and the second tension spring fixing part, contacts a fulcrum shaft on the housing, so that the plunger moves further forward due to its inertial force even after said contact, so that the rotation lever rotates around the fulcrum shaft in the direction that the second tension spring fixing part of the rotatable lever moves backward, whereby the tension spring is again expanded via the rotatable lever and urges the plunger toward the rear end.