A hammer drive mechanism is provided for converting rotary drive from a motor to reciprocatory movement of an impact member of a hammer drill. The mechanism comprises a rotatable plate adapted to be rotated by the motor, an input drive member associated with the rotatable plate in an eccentric position with respect to the axis of rotation of the rotatable plate, an output drive member associated with the impact member, and a crank shaft having a respective driver adjacent each of its ends. Each driver engages with, and is complementary to a respective one of the drive members. At least one end portion of the crank shaft comprises a lubricating aperture which opens into the adjacent driver to provide a lubrication path to the engaging surfaces of the drivers and the drive members.

The present invention discloses an electric chisel capable of being matched with a domestic electric drill to be used. The electric chisel comprises an electric drill, a casing, a push rod and chisel head mechanism and a groove cam mechanism. The top of the casing is provided with an oil hole, and a rubber plug is arranged on the oil hole to be used for preventing dust; the two ends of the groove cam mechanism are provided with a first bearing and a second bearing respectively, and a first groove and a second groove are formed below the first bearing and the second bearing respectively and positioned in the inner wall of the casing. The groove cam mechanism is provided with a groove, and the push rod and chisel head mechanism is connected with the groove cam mechanism and performs reciprocating motion up and down in the groove of the groove cam mechanism. During the use, the whole electric chisel is installed on the domestic electric drill, and when the groove cam mechanism is driven by the electric drill to rotate, the push rod and chisel head mechanism performs liner reciprocating motion. The electric chisel is simple in structure, small in size, portable and convenient to operate and can quickly chisel floors or wall tiles.

A mobile power tool comprising a drive unit is disclosed. The drive unit has an aqueous lubricant and/or the drive unit is set up for operation with the aqueous lubricant, wherein, before the start of a running-in phase of the drive unit, a bond roughness sigma of two interacting contact surfaces of the drive unit is greater than 0.01 m, preferably at least 0.1 m.

Lubrication system includes a drive fluid valve member and a detune valve member. The drive fluid valve member is movable from a first to a second position in response to drive fluid pressure to reduce the volume of a variable volume lubricant charge chamber. The detune valve member is movable from a first to a second position in response to lubricant pressure within the lubricant charge chamber, and is adapted to permit fluid communication between inlet and bypass fluid passages in its the first position and to disengage the fluid connection in its second position.

Lubrication system includes a drive fluid valve member and a detune valve member. The drive fluid valve member is movable from a first to a second position in response to drive fluid pressure to reduce the volume of a variable volume lubricant charge chamber. The detune valve member is movable from a first to a second position in response to lubricant pressure within the lubricant charge chamber, and is adapted to permit fluid communication between inlet and bypass fluid passages in its the first position and to disengage the fluid connection in its second position.

A plug assembly configured for installation in a hammer assembly, the plug assembly comprising a cylindrical plug and an anti-rotation component. The cylindrical plug may include a plug head and a plug body. The plug head may include a first hole and a second hole opposite the first hole, each hole extending from the outer surface of the plug head. The anti-rotation component may include a first linear portion and a second linear portion. The first linear portion and second linear portion may both be configured to fixably engage with the hammer assembly.

A plug assembly configured for installation in a hammer assembly, the plug assembly comprising a cylindrical plug and an anti-rotation component. The cylindrical plug may include a plug head and a plug body. The plug head may include a first hole and a second hole opposite the first hole, each hole extending from the outer surface of the plug head. The anti-rotation component may include a first linear portion and a second linear portion. The first linear portion and second linear portion may both be configured to fixably engage with the hammer assembly.

A lubrication system for a hydraulic hammer is disclosed. The lubrication system includes a housing having a first chamber, and a control valve, disposed proximal to a first end of the first chamber, moveable from a closed position to an open position. A piston is received within the first chamber and moveable between a first position and a second position. The piston includes a first end having a cavity, and a second end facing towards a second chamber, which receives hydraulic fluid therein. In the second position, when the first chamber is filled with air in the first position of the piston, the cavity defined at the first end of the piston maintains pressure of the air less than a biasing force of a resilient member that keeps the control valve in the closed position.

A lubrication system for a hydraulic hammer is disclosed. The lubrication system includes a housing having a first chamber, and a control valve, disposed proximal to a first end of the first chamber, moveable from a closed position to an open position. A piston is received within the first chamber and moveable between a first position and a second position. The piston includes a first end having a cavity, and a second end facing towards a second chamber, which receives hydraulic fluid therein. In the second position, when the first chamber is filled with air in the first position of the piston, the cavity defined at the first end of the piston maintains pressure of the air less than a biasing force of a resilient member that keeps the control valve in the closed position.

A power tool comprises a driving mechanism and a gear housing space (105a) which houses the driving mechanism. A lubricant is provided to the driving mechanism inside a gear housing (105). The driving mechanism includes a driving motor (110) having a motor shaft (111). The motor shaft (111) includes an inner communicating opening (191), an outer communicating opening (192) and an air passage (193) which connects the inner communicating opening (191) and the outer communicating opening (192). At least a part of the air passage (193) is arranged inside the motor shaft (111), and the passage (193) communicates with the gear housing space (105a) via the inner communicating opening (191) and also communicates with the outer space of the gear housing (105) via the outer communicating opening (192).