Abstract: A screw-tightening tool includes a housing, a spindle, a motor, and a power-transmitting mechanism including a sun member, a ring member, a carrier member and a planetary roller. The power-transmitting mechanism is configured such that, when the ring member moves rearward to be closer to the sun member in response to rearward movement of the spindle, the planetary roller transmits power of the motor to the spindle owing to frictional force between the planetary roller and each of a first tapered surface of the sun member and a second tapered surface of the ring member. The sun member is configured to move from a first position to a second position, which is forward of the first position, when the frictional force reaches a threshold, and to move from the second position to the first position when the frictional force falls below the threshold.

Abstract: A power tool may include: a motor; a power transmission mechanism connected to the motor; a housing that houses the motor and the power transmission mechanism; a tip tool holder connected to the power transmission mechanism and holding a tip tool; and a cover covering at least a part of the tip tool. The cover may include: a fixed cover portion fixed to the housing; a movable cover portion movable with respect to the fixed cover portion; and an operation member mechanically connected to the movable cover portion and configured to move the movable cover portion with respect to the fixed cover portion.

Abstract: A screw-tightening tool includes a housing, a spindle, a motor, and a power-transmitting mechanism including a sun member, a ring member, a carrier member and a planetary roller. The power-transmitting mechanism is configured such that, when the ring member moves rearward to be closer to the sun member in response to rearward movement of the spindle, the planetary roller transmits power of the motor to the spindle owing to frictional force between the planetary roller and each of a first tapered surface of the sun member and a second tapered surface of the ring member. The sun member is configured to move from a first position to a second position, which is forward of the first position, when the frictional force reaches a threshold, and to move from the second position to the first position when the frictional force falls below the threshold.

Abstract: A working machine includes: an output shaft to which a tip tool is attachable; a housing rotatably supporting the output shaft; and a protection cover attached to the housing so as to cover an outer periphery of the tip tool which is attached to the output shaft. The protection cover is configured to be displaceable between a processing position to expose a part of the outer periphery of the tip tool to thereby allow cutting of a workpiece, and a protecting position to cover the outer periphery of the tip tool more than in the processing position, and is biased by a biasing member to be displaced from the processing position to the protecting position.

Abstract: A power tool may include: a motor; a power transmission mechanism connected to the motor; a housing that houses the motor and the power transmission mechanism; a tip tool holder connected to the power transmission mechanism and holding a tip tool; and a cover covering at least a part of the tip tool. The cover may include: a fixed cover portion fixed to the housing; a movable cover portion movable with respect to the fixed cover portion; and an operation member mechanically connected to the movable cover portion and configured to move the movable cover portion with respect to the fixed cover portion.

Abstract: A grinder according to one aspect of the present disclosure includes a motor, a housing for housing the motor, a spindle protruding from the housing and configured to be driven to be rotated by the motor, a wheel cover configured to cover a part of a tip end tool attached to the spindle, a detector configured to detect the wheel cover, and a controller configured to stop or restrict the spindle being driven by the motor in response to non-detection of the wheel cover by the detector.

Abstract: [Object] To provide a door frame structure and a method for mounting the door frame structure which improve rigidity, prevent deformation that is caused by relative story displacement of a building in the event of an earthquake, and enable easy mounting. [Solution Means] A door frame structure 1 is indirectly mounted to a wall surface 4 via mounting angles 11 fixed to the first reinforcing members 9. Therefore, the door frame structure 1 does not follow relative story displacement of the wall surface 4 caused by lateral vibration in the event of an earthquake, so that deformation of the door frame structure 1 is minimized, and a door 31 can be opened and closed even in an emergency.

Abstract: A grinder includes a motor, a housing, a spindle and a cover. The spindle protrudes downward from the housing, is driven by the motor, and thereby rotates. The cover is provided on the spindle in the circumferential direction and at least partially covers a tool accessory, which is mounted on the spindle. The cover is configured such that at least one part deforms and/or is composed of an elastic material.

Abstract: A working machine includes: an output shaft to which a tip tool is attachable; a housing rotatably supporting the output shaft; and a protection cover attached to the housing so as to cover an outer periphery of the tip tool which is attached to the output shaft. The protection cover is configured to be displaceable between a processing position to expose a part of the outer periphery of the tip tool to thereby allow cutting of a workpiece, and a protecting position to cover the outer periphery of the tip tool more than in the processing position, and is biased by a biasing member to be displaced from the processing position to the protecting position.

Abstract: A grinder according to one aspect of the present disclosure includes a motor, a housing for housing the motor, a spindle protruding from the housing and configured to be driven to be rotated by the motor, a wheel cover configured to cover a part of a tip end tool attached to the spindle, a detector configured to detect the wheel cover, and a controller configured to stop or restrict the spindle being driven by the motor in response to non-detection of the wheel cover by the detector.

Abstract: [Object] To provide a door frame structure and a method for mounting the door frame structure which improve rigidity, prevent deformation that is caused by relative story displacement of a building in the event of an earthquake, and enable easy mounting. [Solution Means] A door frame structure 1 is indirectly mounted to a wall surface 4 via mounting angles 11 fixed to the first reinforcing members 9. Therefore, the door frame structure 1 does not follow relative story displacement of the wall surface 4 caused, by lateral vibration in the event of an earthquake, so that deformation of the door frame structure 1 is minimized, and a door 31 can be opened and closed even in an emergency.

Abstract: A grinder includes a motor, a housing, a spindle and a cover. The spindle protrudes downward from the housing, is driven by the motor, and thereby rotates. The cover is provided on the spindle in the circumferential direction and at least partially covers a tool accessory, which is mounted on the spindle. The cover is configured such that at least one part deforms and/or is composed of an elastic material.