An electric tool is provided with a rotary striking mechanism unit converting the rotational force of a brushless motor to a striking force and applying the striking force to a tip tool. The required rated input of the motor is 1000-1300 W, the motor speed under fixed speed control is 1680010% (min.sup.1), and the variable Ku, which relates to the motor, is defined by the following expression Ku={(stator core outer diameter).sup.2(stator core lamination thickness)(total tooth width)(rotor outer diameter)}{(rated input)(motor speed under fixed speed control)}, wherein the stator core outer diameter, the stator core lamination thickness, the total tooth width and the rotor outer diameter are shown in mm, the rated input is shown in W, the motor speed is shown in min.sup.1, and the Ku value of the motor is set to 14.6Ku21.8.

A planetary gear system with a sun gear, a ring gear co-axial with the sun gear, at least one planetary gear meshing with both the sun gear and the ring gear, and a planetary gear carrier which rotationally supports the at least one planetary gear. A torque clutch is supported by and connected directly between two of the sun gear, the ring gear, the at least one planetary gear and the planetary gear carrier. The torque clutch prevents relative rotation when an acting torque is below a predetermined torque value and allows relative rotation when the acting torque is above the predetermined torque value. A torque threshold adjustment mechanism is provided for adjusting the predetermined value of the torque at which the torque clutch slips.

A machine tool is disclosed. The machine tool has a tool receptacle for receiving a tool on a working axis, a housing, and a striking mechanism. An impact stop is provided for a beater or an intermediate beater. An impact absorber has two polymer-based absorber rings that are offset axially to one another and are disposed so that they overlap radially and has two iron-based disks disposed axially between the absorber rings.

A handheld power tool has a tool socket (2) to hold a tool (4) along a working axis (11), a motor (5) and a slip clutch (21) having a number of blocking elements. A sensor (27) serves to record a measured signal (28) as the measure of vibrations inside the handheld power tool (1). A band-pass filter (29) has a pass range in which a frequency lies that is equal to the product of the rotational speed of the wheel (22) on the drive side and the number N of blocking elements (24). The measured signal (28) filtered by the band-pass filter (29) is fed to an evaluation unit (30). When the filtered measured signal (28) exceeds a limit value, the evaluation unit (30) reduces the rotational speed of the motor (5).

A suction extraction device has a fan, a suction head, a channel leading from the suction head to the fan, a dust filter and a collection container to hold the dust that has been deposited on the dust filter. The suction head has a tubular cavity that is arranged around the working axis and that serves to accommodate the connection section of the suction drill bit. Arranged in the cavity is a flow sensor that has a sensor surface facing the working axis and that serves to emit a measuring signal that is indicative of the air flow that is striking the sensor surface. An evaluation unit emits an error signal in response to the measuring signal if the measuring signal is lower than a threshold value for at least a prescribed period of time, whereas it suppresses the error signal if the measuring signal exceeds the threshold value during the prescribed period of time. A signaling unit displays the error signal to a user.

A hand-held power tool has a tool socket 2 to hold a tool on a working axis 11. A pneumatic striking mechanism 6 has an exciter piston 13 that is forced to move periodically along the working axis 11 by a motor 5 and it also has a striker 14 that is coupled to the exciter piston 13 via a pneumatic chamber 18. The exciter piston 13 has a cylindrical main body 21 made of a polymer. One or more rings 24 containing copper surround the main body 21. The rings 24 protrude from the main body 21 in the radial direction.

A power tool having a rotary hammer mechanism has a motor, a driving mechanism, a tool body that houses the motor and the driving mechanism, a handle having a grip part, and a first operation member. The driving mechanism is configured to operate by power of the motor in an action mode that is selected from a plurality of operation modes including a first mode of at least rotationally driving a tool accessory around a driving axis and a second mode of only linearly driving the tool accessory along the driving axis. The grip part extends in a direction crossing the driving axis and is configured to be held by a user. The first operation member is on the tool body and faces the grip part. The first operation member is configured to be manually operated by the user to change the action mode of the driving mechanism.

The power tool includes: a handle; a biasing member for biasing the handle in a direction away from a final output shaft in the axial direction; at least one guiding member disposed between a housing and a first part of the handle so as to extend in the axial direction and configured to slidably guide relative movement between the handle and the housing; and at least one elastic member disposed at least one of between the at least one guiding member and the housing and between the at least one guiding member and the first part of the handle. The at least one guiding member is disposed so as to be movable relative to the housing or the handle in a crossing direction that crosses the axial direction by elastic deformation of the at least one elastic member in the crossing direction.

A rotary hammer includes a tool body, a tool holder, a cylinder, and a coupling member. The tool holder has a tubular shape and a longitudinal axis. The tool holder is configured to hold a tool accessory to be movable along the longitudinal axis and is supported by the tool body to be rotatable around the longitudinal axis. The cylinder extends coaxially with the tool holder and is supported by the tool body to be rotatable around the longitudinal axis. The coupling member is between the tool holder and the cylinder in a radial direction of the tool holder and is engaged with the tool holder and the cylinder to couple the tool holder and the cylinder together such that the tool holder and the cylinder integrally rotate.

A hammer drill serving as an impact tool is provided with a crank housing that accommodates a crankshaft, and a cylinder accommodated in the crank housing. Receiving portions that receive the cylinder which is pressed rearward are provided at multiple locations of the crank housing in the front-rear direction. At least one of the receiving portions is disposed to receive the rear-end portion of the cylinder. A portion of the cylinder, which is received by another one of the receiving portions is a circlip (circumferential member) made of a metal.