The disclosure provides a work tool having an electric motor, a power transmission means that receives motive power from the electric motor and transmits the motive power to a tip tool, a gear housing for accommodating at least a portion of the power transmission means, weights swingably supported on the gear housing, and coil springs that function as an urging means for urging the weights such that the weights are located at an initial neutral position, wherein the weights and the coil springs are provided respectively on the two sides of the gear housing so as to put the power transmission means therebetween, and a rotational support axle is provided that functions as a connecting means for connecting the weights provided on both sides of the gear housing so as to connect the weights such that the weights swing integrally.

The invention relates to an impact machine which is adapted to perform a hammering operation on a surface or an object to be worked upon. In particular, a vibration reduction arrangement is attached to the housing and comprises a moveable counterweight, interacting with a motion reversing arrangement having a non-linear spring characteristics, such that the motion of the counterweight can be brought into a counter-acting movement in relation to the vibrations in the housing of the hammering element thus substantially reducing the vibrations. A spring action arrangement is arranged inside said counter weight, the counter weight being movable a first distance without actuating the spring action arrangement, and the counterweight comprises displaceable projecting member for actuating the spring action arrangement.

A work tool includes a driving motor, a rotary shaft member configured to be rotationally driven by the driving motor, a swinging member configured to be caused to swing by rotation of the rotary shaft member, a tool accessory driving mechanism configured to drive a tool accessory by swinging of the swinging member, a body housing the driving motor, the rotary shaft member, the swinging member and the tool accessory driving mechanism, and a vibration reducing mechanism configured to reduce vibration caused in the body. The vibration reducing mechanism includes a dynamic vibration reducer having an elastic member and a weight, and a connecting member connecting the weight and the swinging member. The vibration reducing mechanism is configured to reciprocate the weight via the connecting member by the swinging of the swinging member.

An impact tool has a body and a striking mechanism that drives a tool accessory in a prescribed longitudinal direction. The body has a first body element on which the striking mechanism is provided, and a second body element. The first body element and the second body element are connected via a cushioning mechanism. A vibration reducing mechanism is provided on the first body element.

The hand-held power tool has a tool holder (2) for holding a tool (4) along a working axis (12). A hammer mechanism (6) has a striker (15) that is moved periodically along the working axis at an impact rate. A drive control (18) of the hammer mechanism (6) sets the impact rate to a set point value. A vibration absorber (19) has an oscillator (21) that moves along the working axis (12) about a resting position and one or multiple springs (20) that drive the oscillator (21) back into the resting position. A calibration phase comprises the following steps: detection of an acceleration using the acceleration sensor (24); determination of a minimum of the acceleration by varying the impact rate in a range of between 90% and 110% of the set point value; and adjusting the set point to the impact rate associated with the ascertained minimum.

A rotary hammer is adapted to impart axial impacts to a tool bit. The rotary hammer comprises a housing, a motor supported by the housing, a gearcase, and a spindle housed in the gearcase and coupled to the motor for receiving torque from the motor, causing the spindle to rotate. The rotary hammer also comprises a reciprocating impact mechanism operable to create a variable pressure air spring within the spindle. The rotary hammer also comprises a vibration damping mechanism including a base on the gearcase, a counterweight circumscribing the base, and a first spring arranged between the base and the counterweight and defining a first biasing axis that is parallel to the reciprocation axis. The vibration damping mechanism also includes a second spring arranged between the base and the counterweight and arranged along the first biasing axis.

A work tool includes a motor, a driving mechanism, a housing, a handle, a detecting mechanism and an elastic support part. The detecting mechanism is configured to detect information corresponding to an operating state of the work tool. The elastic support part supports the detecting mechanism so as to be movable relative to the housing in at least two of a front-rear direction, an up-down direction and a left-right direction. The elastic support part includes at least one elastic member disposed between the detecting mechanism and the housing. The elastic support part has respectively different spring constants in the at least two directions.

A hand-held power tool includes a tool holder for holding a tool on a working axis, a pneumatic striking mechanism for striking the tool, and an absorber, which includes a bending spring, situated transversely to the working axis, and a mass body. A countershaft is driven by the motor around a rotation axis which runs in parallel to the working axis. A wobble drive for driving the pneumatic striking mechanism is situated on the countershaft. In addition, a cam disk is situated on the countershaft and includes a cam which projects in a start-up direction which runs in parallel to the working axis. The bending spring includes a counterpiece provided relative to the cam. The cam, which abuts the counterpiece, pretensions the bending spring in the start-up direction.

A hand-held power tool has a tool holder for holding a tool along a working axis. A hammer mechanism has a striker that is moved periodically at an impact rate along the working axis between a turning point in the proximity of the tool and a turning point remote from the tool. A drive control of the hammer mechanism sets the impact rate to a set point value. A vibration absorber has an oscillator that moves along the working axis about a resting position and one or multiple springs that drive the oscillator back into the resting position. A first sensor is used to determine a phase of the motion of the striker. A sensor is used to determine a first phase of a compression point of the hammer mechanism. Another sensor is used to determine a second phase of a turning point in the proximity of the tool, of the hammer mechanism. A damping controller adapts the set point value in such a way that a phase difference between the first phase and the second phase is less than a threshold value.

The invention relates to an impact machine (100, 200) which is adapted to perform a hammering operation on a surface or an object to be worked upon. In particular, a vibration reduction arrangement (140, 240) is attached to the housing (105, 205, 305, 405) and comprises a movable counterweight, interacting with a motion reversing arrangement having a non-linear spring characteristics, such that the motion of the counterweight can be brought into a counter-acting movement in relation to the vibrations in the housing (105, 205, 305, 405) of the hammering element (110, 210, 310, 410) thus substantially reducing the vibrations.