This disclosure pertains to a post driver apparatus of simplified and compact construction. The apparatus can be easily attached to a vehicle equipped with a universal quick attach hitch and having auxiliary hydraulics, for example a farm or construction vehicle. The apparatus includes a hydraulic motor that is driven by the auxiliary hydraulics of the vehicle to which the apparatus is attached. The hydraulic motor rotates a drive wheel of the apparatus which is operatively connected with a weight piston of the apparatus. Rotation of the drive wheel lifts and then drops the weight piston on each rotation of the drive wheel. With the apparatus positioned on the top end of a post, each time the weight piston is dropped it impacts the top of the post and drives the post downwardly. The apparatus is equipped with a safety feature that prevents rotation of the drive wheel from operatively raising the weight piston until the apparatus is positioned on top of a post and exerts a force on the top end of the post.

Hammer drill and/or chipping hammer having a drive motor, an impact mechanism and a tool fitting for fitting a tool, wherein the impact mechanism has an anvil that is axially displaceable in an anvil guide and acts on the tool, wherein the impact mechanism has an idle-strike damper element and a rebound-strike damper element, which are formed in one piece with one another and as such form a combined damper element, wherein the anvil guide is arranged outside, preferably only outside the combined damper element.

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 hammer assembly used in a machine is described. The hammer assembly comprises a power member, a tool member, and a housing member. The housing member includes a first set of channels and a second set of channels. The first set of channels is disposed along a first axis and the second set of channels is disposed along a second axis in an orthogonal direction with respect to the first axis. The hammer assembly is rotated by an angle to make use of any one of the first set of channels or the second set of channels. The first set of channels is shaped to receive a first set of pins and the second set of channels is shaped to receive a second set of pins for engagement of the housing member and the tool member.