An electric powered pneumatic balancer is provided. In an embodiment it includes: a housing; an air balancer located in the housing; and a compressor located in the housing. The housing includes an opening to receive air to the compressor as it generates compressed air. The compressor is in fluid communication with the balancer which operates in response to receipt of the pressurized air from the compressor. An electrical power supply is in electrical communication with the compressor to power the compressor to generate the pressurized air.

A pneumatic and manual clutch of a power winch provides an option of controlling the clutch by a manual or pneumatic method. The pneumatic control method just needs to connect a pump connector of an air pump to a pneumatic connector of the clutch properly to start or stop the air pump even when a user is standing at a position far from the power winch and the clutch can be turned on and off by starting or stopping the air pump. Either a cable or wireless remote control can be used to start or stop the air pump, to provide a very convenient operation.

A pneumatic and manual clutch of a power winch provides an option of controlling the clutch by a manual or pneumatic method. The pneumatic control method just needs to connect a pump connector of an air pump to a pneumatic connector of the clutch properly to start or stop the air pump even when a user is standing at a position far from the power winch and the clutch can be turned on and off by starting or stopping the air pump. Either a cable or wireless remote control can be used to start or stop the air pump, to provide a very convenient operation.

A valve assembly and a hydraulic circuit including the valve assembly are provided. The valve assembly comprises a hydraulically actuated valve configured to be biased from a first control position to a second control position by a hydraulic pressure applied to a first fluid port of the hydraulically actuated valve. A first switching threshold pressure required to switch the hydraulically actuated valve to its second control position when applied to the first fluid port of the hydraulically actuated valve in its first control position differs from a second switching threshold pressure required to keep the hydraulically actuated valve in its second control position when applied to the first fluid port of the hydraulically actuated valve in its second control position.

A main winch system of a rotary drilling rig includes a main action loop, a pilot control loop, and a feedback control loop. The main action loop includes an engine, a hydraulic pump, a main control valve, a balance valve, a main winch motor, and an oil tank. The pilot control loop includes a pilot handle, a solenoid valve I, a pressure relay, and the main control valve in the main action loop. The feedback control loop includes a solenoid valve II and the hydraulic pump and the main control valve in the main action loop. In response to a lifting action of the pilot handle for the main winch, under the control of a button, the solenoid valve II is energized continuously, and the solenoid valve I is energized and de-energized according to a given rule.

A hydraulically actuated liftable and lowerable hook of a crane has a hydraulic system comprises at least one working machine with a hydraulic motor driving a winch. At least one drive machine comprising a pump is connected directly or indirectly to at least one of the working machines by means of two connections via corresponding working lines, which serve as a feed or return depending on the operating state of the working machine. A lowering brake valve is provided in one working line and is connected to the other working line via a control line such that the lowering brake valve is displaceable against a restoring force by pressure, which prevails in the other working line and is forwarded via the control line, from the blocking position of said valve into a through-flow position for lowering the hook by means of a primary winch.

A hydraulically actuated liftable and lowerable hook of a crane has a hydraulic system comprises at least one working machine with a hydraulic motor driving a winch. At least one drive machine comprising a pump is connected directly or indirectly to at least one of the working machines by means of two connections via corresponding working lines, which serve as a feed or return depending on the operating state of the working machine. A lowering brake valve is provided in one working line and is connected to the other working line via a control line such that the lowering brake valve is displaceable against a restoring force by pressure, which prevails in the other working line and is forwarded via the control line, from the blocking position of said valve into a through-flow position for lowering the hook by means of a primary winch.

A hydraulic driving apparatus that drives a plurality of driving subjects and regenerates energy thereof. This hydraulic driving apparatus includes: a first pump motor; a second pump motor that is switchable between a state of moving a first driving subject by hydraulic oil discharged from the first pump motor and a state of being operated as a pump by means of energy of the first driving subject; a first pump motor line that couples the first and second pump motors with each other; a first accumulator connected to the first pump motor line; a regeneration subject hydraulic actuator that moves a second driving subject; a second accumulator that receives hydraulic oil from the regeneration subject hydraulic actuator; a second pump motor line that couples the second accumulator with the first pump motor; and a pressure release changeover valve that opens/closes the second pump motor line.

A pneumatic and manual clutch of a power winch provides an option of controlling the clutch by a manual or pneumatic method, and the pneumatic control method just needs to connect a pump connector of an air pump to a pneumatic connector the clutch properly to start or stop the air pump even when a user is standing at a position far from the power winch and the clutch can be turned on and off by starting or stopping the air pump, and either a cable or wireless remote control can be used to start or stop the air pump, so as to provide a very convenient operation.

A pneumatic and manual clutch of a power winch provides an option of controlling the clutch by a manual or pneumatic method, and the pneumatic control method just needs to connect a pump connector of an air pump to a pneumatic connector the clutch properly to start or stop the air pump even when a user is standing at a position far from the power winch and the clutch can be turned on and off by starting or stopping the air pump, and either a cable or wireless remote control can be used to start or stop the air pump, so as to provide a very convenient operation.