A handheld power tool 1 has a tool socket 2 to hold a tool along a working axis 11. A motor-driven, pneumatic striking mechanism 6 has an exciter 17 which is driven by a motor 5, a striker 14 that is coupled to the exciter 17 via a pneumatic chamber 19, and an intermediate striker 22 arranged on the working axis 11 in the striking direction 12 behind the striker 14. A ventilation opening 30 connects a cavity 29 situated between the striker 14 and the intermediate striker 22 to the environment. A valve 38 that closes the ventilation opening 30 is opened when actuated by the intermediate striker 22 when the intermediate striker 22 is moved into its working position counter to the striking direction 12.

A hammer drill is provided with a hammer mechanism that includes a cylinder having a central axis, a ram having a radial recess slidably mounted within the cylinder, a piston slidably mounted within the cylinder, and a ram catcher. The ram catcher includes a first ring and a second ring surrounding the central axis and forming a groove therebetween, the second ring being located between the first ring and the end of the cylinder. An O-ring that is resiliently-deformable is mounted within the groove and includes an inner side projecting inwardly towards the central axis. When the ram is in a working position, the O-ring is located forward of the ram. When the ram is in a forward position, the O-ring is located in-line with the radial recess of the ram.

The invention relates to a striking hand-held machine tool having a tool holder for holding a striking tool on a working shaft, an electric motor, and a striking mechanism. In the striking direction, the striking mechanism has an exciter piston, a pneumatic chamber, a striker, an intermediate chamber and a rivet snap following one another. A closed channel connects a first channel opening in the pneumatic chamber and a second channel opening in the intermediate chamber. A non-return valve, which shuts off during an air flow from the first channel opening to the second channel opening and opens during an air flow from the second channel opening to the first channel opening, is arranged in the channel. Arranged on the second channel opening is a shut-off valve, which is forced into a position closing the second channel opening when the rivet snap is in the working position.

A handheld power tool 1 has a tool socket 2 to hold a tool along a working axis 11. A motor-driven, pneumatic striking mechanism 6 has an exciter 17 which is driven by a motor 5, a striker 14 that is coupled to the exciter 17 via a pneumatic chamber 19, and an intermediate striker 22 arranged on the working axis 11 in the striking direction 12 behind the striker 14. A ventilation opening 30 connects a cavity 29 situated between the striker 14 and the intermediate striker 22 to the environment. A valve 38 that closes the ventilation opening 30 is opened when actuated by the intermediate striker 22 when the intermediate striker 22 is moved into its working position counter to the striking direction 12.

A power tool includes a housing having a motor housing portion and a front casing coupled to the motor housing portion. The power tool also includes an electric motor positioned within the motor housing portion, a drive assembly having an output shaft to which a tool element for performing work on a workpiece is attachable, and a powdered metal bushing disposed within the front casing that rotatably supports the output shaft.

A rational technique which can realize vibration suppression and reduction of unstable driving elements of a striker. A representative power tool, a first compensation mechanism moves a swinging mechanism from a swinging mechanism reference position to a swinging mechanism moving position and moves a cylinder to a second side, thereby increasing the volume of an air chamber. Further, the second compensation mechanism moves an intermediate element from an intermediate reference position to an intermediate element moving position and moves a striking element to the second side, thereby compensating the volume of the air chamber.

An impact tool includes a tubular tool holder, a hammering mechanism, a resistor, and a biasing member. An impact element moves forward and rearward in conjunction with a piston. An intermediate element is housed movable back and forth between the impact element and a tip tool. The intermediate element abuts on a rear end of the tip tool to indirectly transmit a striking force from the impact element to the tip tool in a normal striking. The resistor is configured to abut on at least one of the intermediate element and the tip tool to apply a resistance to a front-rear movement of at least one of the intermediate element and the tip tool in a non-striking state. The biasing member disposed on the tool holder biases the resistor to a side of at least one of the intermediate element and the tip tool.

The handheld power tool has a tool receptacle for accommodating a tool on a working axis (11) and an electric motor (5). A pneumatic percussion mechanism (6) has an exciter, which is moved back-and-forth by the motor (5) periodically in parallel to the working axis (11), a striker (14), which is movable on the working axis (11) and is coupled via a pneumatic spring (18) to the exciter, and an anvil (19), which is situated movably on the working axis (11) and is situated downstream from the striker (14) in the percussion direction (12). The anvil (19) has a cylindrical anvil section (22) having a diameter and multiple channels (30) extending over the entire length (31) of the anvil section (22). A cross-sectional area of the anvil section (22) is at most 5% less than a circular area defined by the diameter.

A tool includes a housing, a drive assembly including an output shaft extending from the housing such that a tool element for performing work on a workpiece is attachable to the output shaft, and a bushing disposed within the housing. The bushing rotatably supports the output shaft. The bushing is impregnated with lubricant such that the bushing is self-lubricating, and the bushing has an impregnation ratio between about 5% and about 25%.

A sleeve is disclosed for use with a piston of a hydraulic hammer. The sleeve may have a generally cylindrical body with a top end and a bottom end, and a central bore passing axially from the top end of the generally cylindrical body to the bottom end. The generally cylindrical body may be a composite structure including a guide layer forming an inner annular surface of the central bore, an energizer layer located radially outward of the guide layer and being bonded to the guide layer, and a support layer bonded to the energizer layer. The support layer may form an outer surface of the generally cylindrical body.