| 主权项 |
1. A single-shot type air hammer tool, comprising a cylinder, a hammer provided inside the cylinder to freely slide back and forth, an operation switch for introducing compressed air into the cylinder, and an end tool which is mounted in a front side of said cylinder and on which said hammer strikes, for applying striking force to a workpiece W with an end of the end tool, in which, when the operation switch is operated once and the compressed air is introduced into the cylinder, said hammer moves forward from a stop position defined in the cylinder to an impact position where the hammer impacts on the end tool arranged at a front of the stop position, and after the hammer impacts on the end tool, the hammer moves backward toward said stop position and again stops at the stop position,
wherein an elastic member is located at a predetermined position that is on an inner peripheral surface of said cylinder and faces to said hammer situated at said stop position so as to protrude at least partially into the cylinder, a recess is set up to a hammer in the location which corresponds to the elastic member and the hammer situated at the stop position so as to catch the elastic member, the hammer situated at the stop position is urged forward by the pressure of the compressed air introduced due to one operation of said operation switch, a locked state between said recess of the hammer and said elastic member is disengaged, the hammer starts to move forward, the recess of the hammer moving backward from said impact position to the stop position within the cylinder catches the elastic member again, and thus the hammer stops at the stop position, said elastic member is configured with a partially-removed ring body constructed with an annular wire material made of metal and having a circular cross section in which part of the material is removed, a gap is formed, and thus the partially-removed ring body elastically deforms only in the radial direction to be capable of freely expanding or reducing its inside diameter, a recess in which said partially-removed ring body is held in an elastically deformable manner only in the radial direction is formed on the inner peripheral surface of said cylinder, when said hammer is situated at the stop position, the hammer is fitted onto the ring of the partially-removed ring body, in a state where the hammer situated at said stop position is urged forward, the cross-sectional shape of said wire material does not become deformed in the view that is cut in the plane including a center axis of said partially-removed ring body, the inside diameter of the partially-removed ring body expands, and thus said locked state is disengaged, and the hammer leaves from the partially-removed ring body, and when the hammer moves backward and fits onto said partially-removed ring body to be locked again, said cross-sectional shape of the wire material forming the partially-removed ring body does not become deformed, and the inside diameter of the partially-removed ring body expands. |
