US Patent 7987921 Hammer

A hammer comprising: a body; a tool holder mounted on the body for holding a cutting tool; a handle pivotally mounted on the body about an axis; a vibration dampener which connects between the handle and the body and which reduces the amount of angular vibrations transmitted from the body to the handle; a motor mounted within the body; a hammer mechanism mounted in the body, capable of being driven by the motor when the motor is activated, the hammer mechanism, when driven, imparting impacts onto a cutting tool 6 when held by the tool holder; wherein the handle is pivotally mounted about a pivot axis which passes through the centre of gravity of the hammer.