A support plate for a flexible tool that is to be rotated for surface fine machining by grinding or polishing has a plate body with a bottom side that is provided with a circumferentially extending circular contact surface for the flexible tool. A fixation device is arranged at the bottom side and detachably fixes the flexible tool to the contact surface. The plate body has a top side with a drive connector that is axially oriented in a direction of an axis of rotation of the support plate and frictionally connects the support plate to a drive. One or more fatigue markings are provided on or in the top side of the support plate.

A power tool, in particular an angle grinder, having a drive motor accommodated in a housing which drives a rotor shaft, a tool spindle comprising a tool holder which is preferentially connected to the rotor shaft in a power-transmitting manner by a gearing, as well as a control switch for activating the drive motor, wherein the control switch comprises a first switching element which is pivotably mounted on the housing about a pivot axis between a first switch position for switching on the drive motor and a second switch position for switching off the drive motor, and a second switching element which is rotatable about a rotational axis between a locked position which blocks the first switching element from moving into the first switch position and a release position which enables the first switching element to move into the first switch position.

A sander includes a housing, an electric motor, a fan assembly, an eccentric element, a base plate assembly including a base plate, a support for supporting the eccentric element. The support includes a first end surface and a second end surface opposite to each other, and the second end surface is disposed on a side of the support facing the lower surface relative to the first end surface. The sander further includes a counterweight connected to the eccentric element. The ratio of the distance from the centroid of the counterweight to the lower surface of the base plate to the distance from the first end surface of the support to the lower surface of the base plate is greater than or equal to 0.1 and less than or equal to 0.5.

A grinding machine tool comprises a housing, a driving assembly disposed in the housing, a grinding disc driven by the driving assembly, and having a grinding surface and a non-grinding surface, a switch driving the driving assembly, and a pressing plate disposed on the housing and having a first state in which the switch drives the driving assembly to drive the grinding disc when the pressing plate is operated, and a second state in which the switch stops driving the driving assembly when the pressing plate is not operated. The grinding machine tool has a grinding disc braking structure detached from the non-grinding surface when the pressing plate is in the first state; when the pressing plate is in the second state, the grinding disc braking structure moves toward the non-grinding surface and contacts with the grinding disc to stop the grinding disc from rotating.

A grinding machine tool comprises a housing, a driving assembly disposed in the housing, a grinding disc driven by the driving assembly, and having a grinding surface and a non-grinding surface, a switch driving the driving assembly, and a pressing plate disposed on the housing and having a first state in which the switch drives the driving assembly to drive the grinding disc when the pressing plate is operated, and a second state in which the switch stops driving the driving assembly when the pressing plate is not operated. The grinding machine tool has a grinding disc braking structure detached from the non-grinding surface when the pressing plate is in the first state; when the pressing plate is in the second state, the grinding disc braking structure moves toward the non-grinding surface and contacts with the grinding disc to stop the grinding disc from rotating.

A dust collector in one aspect of the present invention comprises a dust collection portion, a communication portion, and an interlock operation control portion. When the communication portion receives an interlock command transmitted from an electric working machine, the interlock operation control portion makes the dust collection portion operate interlocking with the electric working machine. The interlock operation control portion includes a storage portion, in which identification information specific to the electric working machine with which the dust collection portion is to be made to perform the interlock operation is stored.

An ultrasonic resonator support structure including a holder supports an ultrasonic resonator at both sides such that the ultrasonic resonator is rotatable to the holder. The ultrasonic resonator includes an ultrasonic horn with a machining tool attached, and a first booster and a second booster coaxially fixed one by one to both ends in the axial directions of the ultrasonic horn. The holder has a rolling bearing mechanism that rotatably supports the first booster side of the ultrasonic resonator and a gas bearing mechanism that rotatably supports the second booster side of the ultrasonic resonator.

An ultrasonic resonator support structure including a holder supports an ultrasonic resonator at both sides such that the ultrasonic resonator is rotatable to the holder. The ultrasonic resonator includes an ultrasonic horn with a machining tool attached, and a first booster and a second booster coaxially fixed one by one to both ends in the axial directions of the ultrasonic horn. The holder has a rolling bearing mechanism that rotatably supports the first booster side of the ultrasonic resonator and a gas bearing mechanism that rotatably supports the second booster side of the ultrasonic resonator.

Provided is a power tool capable of performing braking in which deterioration and breakage of elements are inhibited. In a brake control, an arithmetic unit 21: performs a switching control of a combination of any of upper arm side Q1-Q3 switching elements and any of lower arm side switching elements Q4-Q6 while sequentially switching the elements; and causes a current to flow in a closed loop (a closed loop in the same direction as during driving of the power tool) in order through any of the upper arm side Q1-Q3 switching elements, stator coils 6e, any of the lower arm side switching elements Q4-Q6, and a first diode bridge 15.

A dust collector in one aspect of the present invention comprises a dust collection portion, a communication portion, and an interlock operation control portion. When the communication portion receives an interlock command transmitted from an electric working machine, the interlock operation control portion makes the dust collection portion operate interlocking with the electric working machine. The interlock operation control portion includes a storage portion, in which identification information specific to the electric working machine with which the dust collection portion is to be made to perform the interlock operation is stored.