A handheld sanding device according to the present invention includes: a power generation unit configured to generate rotating force for sanding operation; a power transmission unit configured to be coupled to the power generation unit, and to transmit the rotating force generated by the power generation unit; a sanding unit configured to be rotated by the rotating force, transmitted through the power transmission unit, in order to sand a sanding target surface; and a shaft coupling unit configured to connect the power transmission unit and the sanding unit to each other so that the sanding unit is freely inclined based on the power transmission unit, thereby improving the close contact between the sanding target surface and the sanding unit while making it easy to carry and also preventing the sanding target surface from being eccentrically worn during sanding operation.

An adjustable stroke mechanism has a housing with a central axis and a wall defining a cavity. At least one counterweight is movably disposed, at least partially, within the cavity. A mounting assembly is disposed, at least partially, within the cavity. The mounting assembly has a workpiece attachment mechanism. A stroke adjustor couples the at least one counterweight with the mounting assembly. The stroke adjustor enables the counterweight and mounting assembly to move with respect to one another such that a distance between the counterweight and the mounting assembly may be variably adjusted which, in turn, variably adjusts a stroke radius of the workpiece attachment mechanism with respect to the central axis of the housing.

An adjustable stroke mechanism has a housing with a central axis and a wall enclosing a cavity. At least one counterweight is movably disposed within the cavity. A mounting assembly is disposed within the cavity. The mounting assembly has a workpiece attachment mechanism. A stroke adjustor couples the at least one counterweight with the mounting assembly. The stroke adjustor enables the counterweight and mounting assembly to move with respect to one another such that a distance between the counterweight and the mounting assembly is variably adjusted which, in turn, variably adjusts a stroke radius of the workpiece attachment mechanism with respect to the central axis of the housing.

An adjustable stroke mechanism has a housing with a central axis and a wall enclosing a cavity. At least one counterweight is movably disposed within the cavity. A mounting assembly is disposed within the cavity. The mounting assembly has a workpiece attachment mechanism. A stroke adjustor couples the at least one counterweight with the mounting assembly. The stroke adjustor enables the counterweight and mounting assembly to move with respect to one another such that a distance between the counterweight and the mounting assembly is variably adjusted which, in turn, variably adjusts a stroke radius of the workpiece attachment mechanism with respect to the central axis of the housing.

A sanding disc stabilizing structure of an orbital sander comprises a casing, a sanding power source, a sanding disc, and at least four springs. The sanding power source is assembled on the casing and comprises a drive shaft and a tool holder disposed on the drive shaft and offset from an axis of the drive shaft. The center of the sanding disc driven by the sanding power source to perform an orbital motion is disposed on the tool holder with a locking screw. Two ends of each of the at least four springs are respectively disposed on the casing and the sanding disc. The free length of each of at least four springs is greater than the spacing between an installation part of the casing and an installation part of the sanding disc provided for one of the at least four springs.

An adjustable stroke mechanism has a housing with a central axis and a wall enclosing a cavity. At least one counterweight is movably disposed within the cavity. A mounting assembly is disposed within the cavity. The mounting assembly has a workpiece attachment mechanism. A stroke adjustor couples the at least one counterweight with the mounting assembly. The stroke adjustor enables the counterweight and mounting assembly to move with respect to one another such that a distance between the counterweight and the mounting assembly is variably adjusted which, in turn, variably adjusts a stroke radius of the workpiece attachment mechanism with respect to the central axis of the housing.

An adjustable stroke mechanism has a housing with a central axis and a wall defining a cavity. At least one counterweight is movably disposed, at least partially, within the cavity. A mounting assembly is disposed, at least partially, within the cavity. The mounting assembly has a workpiece attachment mechanism. A stroke adjustor couples the at least one counterweight with the mounting assembly. The stroke adjustor enables the counterweight and mounting assembly to move with respect to one another such that a distance between the counterweight and the mounting assembly may be variably adjusted which, in turn, variably adjusts a stroke radius of the workpiece attachment mechanism with respect to the central axis of the housing.

A tool spindle having a spindle shaft rotationally-drivable about a spindle axis, a clamping system for the automatic chucking and unchucking of a tool, wherein the clamping system comprises a movement device enabling at least one movable and/or deformable clamping body of the clamping system to be transferred from a first position into a second position by execution of a movement of a part of the movement device in relation to the spindle shaft, wherein the tool is chucked on the tool spindle in the first position and the tool can be removed from the tool spindle in the second position, wherein it comprises a balancing system, which is integrated into the tool spindle so that it rotates jointly with the rotationally-drivable spindle shaft, which is arranged coaxially in relation to the spindle axis, and which is mounted so it is axially movable.

A machine tool, namely a handheld machine tool or a semi-stationary machine tool, having a drivetrain, which includes a tool shaft rotatably mounted on a drive support by means of a bearing assembly and a tool holder arranged on the tool shaft for an in particular disk-like working tool, wherein the tool shaft is rotationally drivable by a drive motor of the machine tool around a rotational axis, and wherein a balancing device is arranged on the tool shaft, which includes a guide body having at least one orbital path extending around the rotational axis and at least one balancing body movably mounted in the orbital path. It is provided in the machine tool that the drive support is movably mounted on a holder of the machine tool, wherein a relative position of the drive support in relation to the holder is adjustable by the balancing device.

A balancing device for each rotating piece, the rotating piece defining an axis of rotation, the balancing device including: a fixed portion, a mobile portion defining a central axis. The balancing device constrained to the rotating piece so that the central axis substantially coincides with the rotation axis. The balancing device including at least one eccentric mass, rotatable around the central axis and not balanced with respect to the central axis. The balancing device further including apparatus for movement of the eccentric masses, including a magnetic brake and being able to rotate the eccentric masses, with respect to the rotating piece around the central axis.