A piston guiding element, rock drilling machine and method for supporting a front end portion of a percussion piston of a rock drilling machine. The piston guiding element includes a braking recess at its rear end. The element further includes at least one bearing sleeve, which is provided with two axially successive slide bearing sections. Hydraulic fluid is conveyed between the slide bearing sections via a feed system.

A piston guiding element, rock drilling machine and method for supporting a front end portion of a percussion piston of a rock drilling machine. The piston guiding element includes a braking recess at its rear end. The element further includes at least one bearing sleeve, which is provided with two axially successive slide bearing sections. Hydraulic fluid is conveyed between the slide bearing sections via a feed system.

A hand-held power tool, which has a pneumatic impact mechanism with an impact piston that is able to be moved back and forth along a working axis in a guide tube by a pneumatic spring, is characterized in that a cylindrical surface of the impact piston has a plurality of cutouts that are distributed in the circumferential direction, and the cutouts take up at least 30%, at least 50% and/or at least 70% of the circumference of the cylindrical surface of the impact piston.

A hand-held power tool, which has a pneumatic impact mechanism with an impact piston that is able to be moved back and forth along a working axis in a guide tube by a pneumatic spring, is characterized in that a cylindrical surface of the impact piston has a plurality of cutouts that are distributed in the circumferential direction, and the cutouts take up at least 30%, at least 50% and/or at least 70% of the circumference of the cylindrical surface of the impact piston.

A power tool having a rotary hammer mechanism is configured to produce hammering motion for driving a tool accessory along a driving axis and rotating motion for rotating the tool accessory around the driving axis. The power tool has a tool holder that is configured to removably hold the tool accessory. The tool holder has a rotation transmitting part configured to transmit rotating power to the tool accessory. A layer formed of carbide of a group 5 element of a periodic table is formed on the rotation transmitting part.

A power tool having a rotary hammer mechanism is configured to produce hammering motion for driving a tool accessory along a driving axis and rotating motion for rotating the tool accessory around the driving axis. The power tool has a tool holder that is configured to removably hold the tool accessory. The tool holder has a rotation transmitting part configured to transmit rotating power to the tool accessory. A layer formed of carbide of a group 5 element of a periodic table is formed on the rotation transmitting part.

An impact tool includes a housing, a motor supported within the housing, a drive assembly configured to convert a continuous rotational input from the motor to intermittent applications of torque on a workpiece, and first and second impact members supported on the drive assembly and configured to deliver impacts to one another. The first impact member includes a core made of a first material having a first hardness, and a sleeve surrounding the core and made of a second material having a second hardness different than the first hardness. The first hardness is less than the second hardness.

An impact tool includes a housing, a motor supported within the housing, a drive assembly configured to convert a continuous rotational input from the motor to intermittent applications of torque on a workpiece, and first and second impact members supported on the drive assembly and configured to deliver impacts to one another. The first impact member includes a core made of a first material having a first hardness, and a sleeve surrounding the core and made of a second material having a second hardness different than the first hardness. The first hardness is less than the second hardness.

An impact mechanism for an impact tool that includes a housing, a piston slidably disposed in the housing and adapted to transfer impact force to a tool bit, and electromagnetic coils disposed between the piston and the housing. The electromagnetic coils are alternately activated to generate respective magnetic fields to cause the piston to move within the housing.

An impact mechanism for an impact tool that includes a housing, a piston slidably disposed in the housing and adapted to transfer impact force to a tool bit, and electromagnetic coils disposed between the piston and the housing. The electromagnetic coils are alternately activated to generate respective magnetic fields to cause the piston to move within the housing.