Abstract: A power tool includes an impact damping mechanism for damping an impact in a direction of rotation of a speed reduction mechanism portion 8.

Abstract: A main valve and a manual operating valve cooperatively control the compressed air supplied to an air motor and a piston. The main valve is responsive to the compressed air supplied from the manual operating valve via an air passage. An orifice is provided in the air passage to reduce the speed of the compressed air supplied to the main valve so that the shift movement of the main valve is delayed when the manual operating valve is closed.

Abstract: An air motor has a rotor rotatable in response to the pressure of pressurized air. A cylindrical rotary member is connected to the air motor for causing a rotation in synchronism with the rotation of the rotor. A rotary slider is slidable in the axial direction along the inner cylindrical wall of the rotary member. A rotational force transmitting mechanism is provided for transmitting the rotation of the rotary member to the rotary slider. A shaft has one end fixed to the rotary slider and the other end equipped with a piston and a driver bit holder. The rotational and axial motion of the rotary slider is transmitted to a driver bit held in the driver bit holder. And, a cylinder guides the axial slide movement of the piston responsive to the pressure of pressurized air applied on a pressure-receiving surface of the piston.

Abstract: A pneumatically operated screw driver having a moving unit rotatable about its axis by rotation of a rotor and movable axially by a pneumatic pressure. The moving unit includes a spline shaft supported by the rotor through a ball spline, and a drive bit aligned with the spline shaft and engageable with a head of a screw. The spline shaft has an annular flange portion. A movable piston is disposed concentrically over the spline shaft and movable in an axial direction thereof with respect to the spline shaft. A spring is disposed over the spline shaft and is interposed between the movable piston and the flange portion. A stop member is provided to a rotor or a frame body. If pneumatic pressure is applied to the movable piston, the latter is axially moved downwardly and is brought into abutment with the stop member. The spline shaft is also moved axially slightly after the movement of the movable piston.

Abstract: A pneumatically operated screw driver having a pneumatically operated rotor rotatably supported in an outer frame. The rotor is only rotatable about its axis. A moving unit is slidably disposed within the rotor. The moving unit has an upper piston and is axially movable upon application of pneumatic pressure to the upper piston. The moving unit is also rotatable about its axis because of spline connection with the rotor. A valve is disposed for selectively applying the pneumatic pressure to the piston and to the rotor. Upon application of the pneumatic pressure, the moving unit is moved downwardly, and the pneumatic pressure is then introduced into the rotor for rotating the same. The rotation of the rotor is transmitted to the moving unit. The valve closes a fluid passage directing to the piston and to the rotor when the moving unit has the lowermost position.

Abstract: An electric hammer drill including a vacuum dust collecting device for collecting dust from an area of an article being drilled by a drill bit wherein a hose extending from a body of the hammer drill is directly connected to an end of a movable first pipe which is slidably received in a stationary second pipe. A fan for transporting the dust by vacuum is fixed on a shaft extending across a dust collecting chamber in the body. The shaft is coaxial with, and releasably coupled with, an armature shaft of a motor. With this releasable coupling, the armature shaft is relatively short and unlikely to bend or flex, so that vibration produced during a drilling operation is small. During the drilling operation, the first pipe slides back and forth along the second pipe as a suction hood moves in a direction opposite to the direction of movement of the drill bit.