Abstract: Plural first exhaust pipes are disposed as exhaust paths at an upper portion of a heat treatment apparatus. Exhaust gases are discharged from the inside of the heat treatment apparatus to the respective exhaust pipes. Inlets of catalyst units are connected to outlets of the first exhaust pipes, and second exhaust pipes are connected to outlets of the catalyst units. Exhaust gases are discharged from exhaust ports of the second exhaust pipes to the outside (e.g., the atmosphere) of the heat treatment apparatus.

Abstract: A hammer drill is equipped with a connector shaft, which is rotationally driven by a motor, a spindle that transmits the rotation through a connector shaft, and a percussive impact impact mechanism that applies a percussive force in the axial direction to a drill bit held by the spindle through performing a reciprocating motion, in the axial direction, relative to a spindle that receives the rotation of the connector shaft through a motion converter mechanism. The hammer drill is provided with a percussive force converter from the percussive impact impact mechanism by changing the speed reduction ratio between the motor and the connector shaft. This makes it possible to adjust the percussive force according to the drill bit used.

Abstract: Plural first exhaust pipes are disposed as exhaust paths at an upper portion of a heat treatment apparatus. Exhaust gases are discharged from the inside of the heat treatment apparatus to the respective exhaust pipes. Inlets of catalyst units are connected to outlets of the first exhaust pipes, and second exhaust pipes are connected to outlets of the catalyst units. Exhaust gases are discharged from exhaust ports of the second exhaust pipes to the outside (e.g., the atmosphere) of the heat treatment apparatus.

Abstract: A hammer drill is equipped with a connector shaft, which is rotationally driven by a motor, a spindle that transmits the rotation through a connector shaft, and a percussive impact means that applies a percussive force in the axial direction to a drill bit held by the spindle through performing a reciprocating motion, in the axial direction, relative to a spindle that receives the rotation of the connector shaft through a motion converter mechanism. The hammer drill is provided with a percussive force converter means from the percussive impact means by changing the speed reduction ratio between the motor and the connector shaft. This makes it possible to adjust the percussive force according to the drill bit used.