A control valve, an impact device for a rock breaking apparatus, and a method are provided. The control valve is an elongated piece with a central axis and radial outer and inner surfaces (Ros, Ris). The control valve includes several control surfaces disposed at axial distances from each other for controlling hydraulic fluid flows (Hff) in response to axial control movement (M). One or more radial surfaces of the control valve include one or more slanted surface (SS) a longitudinal direction of which have oblique orientation in relation to the central axis (Ca) of the control valve. The control valve rotates or turns during a working cycle due to hydraulic flow effecting on the slanted surfaces.

A piledriving apparatus for driving stakes or posts into the ground includes a housing and a ram mounted in the housing. A head is attached to the ram and defines a cavity for receiving a stake. The ram is operable to drive the head against the stake to urge the stake into the ground. Grips for holding the apparatus by the hands of a user are described and claimed. Controls for directing the direction, force, and speed of a piston rod of the ram is disclosed and claimed.

A piledriving apparatus for driving stakes or posts into the ground includes a housing and a ram mounted in the housing. A head is attached to the ram and defines a cavity for receiving a stake. The ram is operable to drive the head against the stake to urge the stake into the ground. Grips for holding the apparatus by the hands of a user are described and claimed. Controls for directing the direction, force, and speed of a piston rod of the ram is disclosed and claimed.

A piledriving apparatus for driving stakes or posts into the ground includes a housing and a ram mounted in the housing. A head is attached to the ram and defines a cavity for receiving a stake. The ram is operable to drive the head against the stake to urge the stake into the ground. Grips for holding the apparatus by the hands of a user are described and claimed. Controls for directing the direction, force, and speed of a piston rod of the ram is disclosed and claimed.

A piledriving apparatus for driving stakes or posts into the ground includes a housing and a ram mounted in the housing. A head is attached to the ram and defines a cavity for receiving a stake. The ram is operable to drive the head against the stake to urge the stake into the ground. Grips for holding the apparatus by the hands of a user are described and claimed. Controls for directing the direction, force, and speed of a piston rod of the ram is disclosed and claimed.