A multi-stroke powered safety hammer including a cylinder having an end, the cylinder mounted to and extending outwardly from a body to the end, and an impact piston disposed within the cylinder for axial reciprocating movement, the impact piston having a striking surface at a front end thereof. The hammer further includes a mount connected releasably over the end of the cylinder and is configured to receive and releasably secure a base of a tool for reciprocating movement, the base including an end having an impact surface. The end of the cylinder is configured to receive the end of the base for reciprocating movement in confronting relation of the impact surface to the striking surface when the base is received and releasably secured by the mount for reciprocating movement.

A hammer is provided that includes a handle, a head, a striking insert, and a claw. The hammer provides for a head with a keyed hole to couple to a keyed projection on a striking insert. The head also includes a dovetail projection that couples to the dovetail connection of the claw. Each component may comprise a different material. For example, the striking insert and the claw comprise one material, and the handle and the head comprise another material. In some embodiments, a slotted punch with a magnetic retainer creates a bore through the face of the head and the striking insert to support a fastener (e.g., a nail) within the head.

Composite gearwheel for an electropneumatic hammer drill, wherein the composite gearwheel has a basic body, consisting of a first material, and an encircling toothing, and wherein the encircling toothing is formed, along a first circular arc, by a toothed body of the composite gearwheel, and is formed, along the remaining second circular arc, by the basic body itself, wherein the toothed body consists of a second material that is different than the first material.

A hammer drill is provided including a housing, a motor mounted within the housing, and a hammer mechanism. The hammer mechanism includes a crank plate or a wobble plate driven by the motor, a con rod coupled to the crank plate or the wobble plate, a piston reciprocatingly driven by the con rod along a longitudinal axis, a ram and a beat piece. At least one of the wobble plate or the con rod is made of sintered steel.

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 knife includes a body including a first end, a second end opposite the first end, and a longitudinal axis that extends centrally through the first end and the second end. The knife further includes a first scoring tip that points in a first direction, a second scoring tip that points in a second direction opposite the first direction, and a scoring tip axis that extends centrally through the first scoring tip and the second scoring tip. The scoring tip axis is perpendicular to the longitudinal axis. A chisel extends from the second end of the body and the longitudinal axis of the body extends centrally through the chisel.

A piston for a hammer drill is a flat piston made from sintered steel. The piston can be impregnated with a lubricant.

A control method for a bore-chiseling portable power tool for machining a substrate by a drill bit includes superimposing a periodic striking on the drill bit at an impact rate and a rotating of the tool holder at a rotational speed in a rotational direction, identifying a material of the substrate being machined by the drill bit by a sensor, adjusting the rotational speed and/or the rotational direction to a first rotational speed and a first rotational direction when the identified material is an iron-based material, and adjusting the rotational speed and/or the rotational direction to a second rotational speed and a second rotational direction when the identified material is a mineral material. The first rotational speed is less than the second rotational speed and the first rotational direction is counter-clockwise and the second rotational direction is clockwise.

A knife including a body having a first end, a second end opposite the first end, and a longitudinal axis that extends centrally through the first end and the second end. The knife further includes a first scoring tip that points in a first direction, a second scoring tip that points in a second direction opposite the first direction, and a scoring tip axis that extends centrally through the first scoring tip and the second scoring tip. The scoring tip axis is perpendicular to the longitudinal axis. A chisel extends from the second end of the body and the longitudinal axis of the body extends centrally through the chisel.

A mallet is described that has at least one cleft, in such a structure that the stress wave created during impact has longer travel way than the length of the mallet as measured along the impact line. This mallet induces longer-lasting and weaker stress wave(s) in the anvil as compared to a solid mallet having the same outer dimensions and more or less the same weight. The Cleft-Mallet increases the effectiveness of the strike, while decreasing the stresses in the anvil.