The present disclosure is directed to a power tool adapted to impart axial impacts to a tool bit. The power tool includes a housing, an electric motor, and a barrel. The power tool also includes a reciprocation drive assembly coupled to the electric motor and configured to convert torque from the electric motor to reciprocating motion of a piston that is received within the barrel for reciprocation therein. The power tool further includes a striker received within the barrel for reciprocation in response to reciprocation of the piston, and an anvil received within the barrel between the striker and the tool bit. The anvil is configured to communicate axial impacts to the tool bit in response to reciprocation of the striker. The anvil defines an opening and an inner bore that communicates with the opening, and the inner bore at least partially receives a shank of the tool bit.

An impact power tool including a housing, a motor supported by the housing, a spindle coupled to the motor for receiving torque from the motor to cause the spindle to rotate, and a reciprocating impact mechanism operable to create a variable pressure air spring within the spindle. The impact mechanism includes a striker received within the spindle that reciprocates along a reciprocation axis in response to the variable pressure air spring, a piston that reciprocates along the reciprocation axis to induce the variable pressure air spring, and a crankshaft configured to convert continuous rotational motion from the motor to reciprocating linear movement of the piston. The crankshaft defines a crank axis perpendicular to the reciprocation axis, and the motor defines a motor axis that is parallel with the reciprocation axis. A center of gravity of the impact power tool is positioned between the motor axis and the reciprocation axis.

A movable support at least partially supports a final output shaft and a driving mechanism, and is integrally movable relative to a housing in an axial direction of a driving axis. A biasing member biases the movable support toward a front side in the axial direction. A first guide shaft extends in the axial direction and slidably guides the movement of the movable support in the axial direction. At least one intermediate shaft rotates in response to rotation of a motor shaft and transmit power of the motor to the driving mechanism. At least one bearing supports an end portion of the at least one intermediate shaft is located in the front side in the axial direction. A single metal support is immovable relative to the housing and supports the at least one bearing. The single metal support has a first hole for partially receiving the first guide shaft.

An impact tool performs a processing operation on a workpiece by carrying out an impact operation on a tool bit in a longitudinal axis direction. The impact tool includes a motor having a rotor and a stator, a tool main body housing the motor, a drive shaft parallel to a longitudinal axis of the tool bit and rotatably driven by the motor, and an oscillating member that is supported by the drive shaft and that carries out an oscillating movement in the axial direction of the drive shaft based on the rotational motion of the drive shaft. A tool drive mechanism is coupled to the oscillating member so that the oscillating movement of the oscillating member linearly moves the tool bit in the longitudinal axis direction. The motor is an outer rotor motor in which the rotor is disposed on an radially outer side of the stator.

An impact tool includes a casing (13) supporting a tip tool (12), a piston (41) provided in the casing (13), an electric motor (11) provided in the casing (13), a motion converting mechanism (45) provided in the casing (13), and a vibration reducing mechanism (47) provided in the casing (13). The vibration reducing mechanism (47) has a supporting member, which is swingable with using a fixing position (J) as a supporting point and a weight (49) attached to a free end side of the supporting member. In a plane including a center line (C), the gravity center (H) of the weight (49) and the gravity center (G) of the casing (13) are disposed at mutually different locations, and the fixing position (J) is disposed on the side of the gravity center (G) relative to the center line (C).

A rotary hammer includes a housing, a first motor supported by the housing and defining a first motor axis, a second motor supported by the housing and defining a second motor axis that is coaxial with the first motor axis, and a spindle coupled to the first motor for receiving torque from the first motor, causing the spindle to rotate. The rotary hammer further includes a reciprocation mechanism operable to create a variable pressure air spring within the spindle. The reciprocation mechanism includes a piston configured to reciprocate within the spindle in response to receiving torque from the second motor, a striker that is selectively reciprocable within the spindle in response to reciprocation of the piston, and an anvil that is impacted by the striker when the striker reciprocates towards the tool bit. The anvil imparts axial impacts to the tool bit.

A workability of a driving work machine is improved by reduction in vibration transmitted to a housing. A driving work machine 10 includes: a cylinder 21 applying a rotational force to a tip tool; a piston 33 applying a striking force to the tip tool; a driving source generating a power; a switching part 61 making switching between at least two operational states including a rotational striking state of transmitting the power as a striking force and a rotational force to the tip tool and a rotational state of transmitting the power as the rotational force but not transmitting the power as the striking force to the tip tool; and a housing 12. The cylinder 21 includes a pushing part 46 pushing the switching part 61 rearward, the switching part 61 is able to switch an operational state of the cylinder 21 by the rearward movement caused by the pushing force of the pushing part 46, and a rubber annular member 72 serving as an anti-vibration part is arranged between the pushing part 46 and the preventing part 71.

An electric power tool includes a motor, a driving side member, and a driven side member. The driving side member and the driven side member have mutually opposed surfaces. A plurality of cam teeth are respectively disposed on concentric circles on the opposed surfaces. The plurality of cam teeth have meshing surfaces inclined at predetermined lead angles. A torque limiter is formed to disengage the engagement of the meshing surfaces of the cam teeth by moving the one member in a separation direction from the other member when load of the driven side member increases. The respective cam teeth are formed such that the lead angles of the meshing surfaces are different between a forward rotation side and a reverse rotation side. A transmission torque transmitted from the driving side member to the driven side member is equal between the forward rotation and the reverse rotation.

An electric power tool includes a motor, a driving side member, and a driven side member. The driving side member and the driven side member have mutually opposed surfaces. A plurality of cam teeth are respectively disposed on concentric circles on the opposed surfaces. The plurality of cam teeth have meshing surfaces inclined at predetermined lead angles. A torque limiter is formed to disengage the engagement of the meshing surfaces of the cam teeth by moving the one member in a separation direction from the other member when load of the driven side member increases. The respective cam teeth are formed such that the lead angles of the meshing surfaces are different between a forward rotation side and a reverse rotation side. A transmission torque transmitted from the driving side member to the driven side member is equal between the forward rotation and the reverse rotation.

A power tool having a hammer mechanism includes a tool body defining the driving axis, a motor housed in the tool body, an elongate handle connected to the tool body in a cantilever manner and extending in a direction intersecting the driving axis, and at least one biasing member disposed between the tool body and the handle. The motor has a motor shaft that is rotatable around an axis parallel to the driving axis. The handle includes a first end portion connected to the tool body to be pivotable around a pivot axis relative to the tool body, a free end, and a grip part disposed between the first end portion and a free end of the handle. The at least one biasing member is configured to pivotally bias the tool body and the handle such that the grip part and the tool body move away from each other.