A remote controlled demolition robot (10) comprising a controller (17) and at least one actuator (12) controlled through a hydraulic system (400) comprising at least one valve (13a) connected to a corresponding actuator for a tool (11b) and a pump (410). The controller (17) is configured to operate in a first mode wherein the fluid flow is controlled through the at least one valve (13a), wherein said valve (13a) is a proportional valve, receive a pressure indication indicating a pressure in the hydraulic system (400) and determine if the pressure in the hydraulic system (400) is above a first mode threshold and/or if a pressure change fulfills a first mode condition, and if so operate in a second mode wherein the at least one valve (13a) is in an opened state and the fluid flow is controlled through the pump (410).

A hydraulic unit includes two pressure connections for supplying devices, in particular hydraulic rescue devices, including a first hydraulic circuit with a first pump arrangement and a first pressure connection and a second hydraulic circuit with a second pump arrangement and a second pressure connection, wherein the pump arrangements are driven at the same time by a common drive, and wherein by a first valve switch the first hydraulic circuit can be connected to the second hydraulic circuit and by a second valve switch the second hydraulic circuit can be connected to the first hydraulic circuit. The valve switches include a spring acting in the direction of an initial position and from the first hydraulic circuit or from the second hydraulic circuit a first control line runs to the first valve switch and from the second hydraulic circuit or from the first hydraulic circuit a second control line runs to the second valve switch.

A dual control hydraulic circuit for a tilting power swivel having a main hydraulic pump providing an operational supply of hydraulic fluid causing a clockwise or counter clockwise rotation of the tilting power swivel. A hydraulic cylinder used to hydraulically power an angular change between a bail and a body, wherein a local control valve can enable extension and retraction of a rod of the hydraulic cylinder. An auxiliary hydraulic pump providing hydraulic fluid at a low pressure, a hydraulic reservoir fluidly connected to the main hydraulic pump and the auxiliary hydraulic pump, an engine connected to the main hydraulic pump, and a hydraulic fluid return line from a local control valve to the hydraulic reservoir used for dual control for operating the hydraulic cylinder to tilt the tilting power swivel and a remote control connected to the local control valve for controlling the local control valve.

A hydraulic drive system includes a pump, a steering actuator, a loading/unloading apparatus actuator, a drive device, a relief valve, and an input unit. The drive device: flows hydraulic oil from the pump to the loading/unloading apparatus actuator when an operating tool is operated; flows the hydraulic oil from the pump to the steering actuator when a steering has become an operated state from a non-operated state regardless of an operation of the operating tool; and causes the hydraulic oil from the pump to be discharged to a tank via the relief valve to increase the torque of an engine when an increase instruction is inputted to the input unit and the steering is in a non-operated state.