Abstract: In a machine for use on uneven terrain having a stabilizing beam providing a lateral extension of the chassis of the machine and having a support jack mounted at each end thereof and movable relative thereto between an operating position in which the jack is vertical and bears on the ground through the intermediary of a sole plate attached to the end of the piston rod of the support jack and a position in which the jack is substantially horizontal and located within the stabilizing beam, a double actuating actuator jack is provided with its cylinder pivoted to the stabilizing beam and its piston rod pivoted to the cylinder of the support jack, and an hydraulic actuating device is provided comprising supply and take-off conduits for pressurized liquid connected to the chambers of the support and actuator jacks through three pressure sensitive non-return valves such that during movement of the support jack to its operating position, the support jack is extended only when the actuator jack is fully extended and

Abstract: A stabilizer beam for stabilizing a machine for use on rough ground for extending the frame of the machine laterally, the stabilizer beam comprising a supporting box girder to be integral with or rigidly attached to the frame of the machine, a supporting beam slidable in the box girder, a bearer jack carrying a bearer shoe and pivotally connected to that one end of the beam to be remote from the machine frame such that the jack is movable from a rest position in which the jack is substantially horizontal and the bearer shoe is in contact with the end face of the beam, and an operative position in which the jack is substantially vertical, means for supporting and guiding the jack in its movement relative to the beam and pivotally mounted on the one end of the beam, means for locking the jack in its vertical position and operable on relative movement between the beam and box girder, and means for pushing and pulling in the direction of the axis of the beam and pivotally connected to the jack, the pushing and pu