Abstract: The invention relates to a work device having a body with an attachment arrangement to attach the work device to a set of booms of a work machine. A pair of jaws fitted to the body includes two jaws arranged to form a grab. A first jaw is fixed to the body and a second jaw is pivoted rotatably to the body to open and close the grab. The rotatable jaw is arranged to be acted on by a hydraulic actuator, to open and close the grab. Between the hydraulic actuator and the rotatable jaw is a wide-angle pivot setup. An arm mechanism, equipped with two pivots fitted to a jaw arm is arranged to belong to the wide-angle pivot setup. In addition, the wide-angle pivot setup is arranged to include a rotatable lever arm fitted between the jaw arm and the body. The rotation angle of the movement created in the rotatable jaw by the wide-angle pivot setup has a magnitude of more than 120°.

Abstract: A hydraulic actuator includes two or more cylinder parts that nest inside each other, each cylinder part including a piston and piston rod forming an operating element and a cylindrical component, inside which the operating element is arranged, the piston of the inner cylinder part being inside the piston rod of the outer cylinder part, chambers formed for each cylinder part, a pressure-medium feed arrangement creating work-movement in the operating element by the pressure medium led to the chambers, a pressure-difference-controlled valve controlling operation of the hydraulic actuator between a first ducting and a second ducting, controlling the feed of the pressure medium among the chambers and a pressure-difference-controlled spool valve including a housing, connecting chambers and a spool arranged to move backwards and forwards in the housing to open and close the connections creating a work movement alternately by the operating element of the inner or outer cylinder part.

Abstract: An energy wood grapple includes a frame, a clamp fitted in the frame, which delimits a jaw together with the frame, as well as a delimbing knife. The delimbing knife is arranged to be loaded against the clamp on the side of the jaw. An accessory for an energy wood grapple includes a fixing detent for fastening the delimbing knife on the pivoting shaft of the clamp included in the energy wood grapple, as well as a hydraulic cylinder to be connected to the energy wood grapple.