DOOSAN INDUSTRIAL VEHICLE CO., LTD Patent applications |
Patent application number | Title | Published |
20130145751 | ENERGY RECLAIMING SYSTEM FOR ELECTRIC FORKLIFT TRUCK - The present disclosure relates to an energy reclaiming system for an electric forklift truck. The energy reclaiming system includes an electronic device operated by a motor when a working machine is raised and operated by a generator when the working machine is lowered, a hydraulic pump/motor connected to the electronic device and configured to perform two functions of a hydraulic pump and a hydraulic motor, a main control valve unit including a lift cylinder operating unit connected to the hydraulic pump/motor and configured to operate a lift cylinder and a secondary consumer operating unit connected to the hydraulic pump/motor and configured to operate a secondary consumer, and a control lever including a control valve configured to control the lift cylinder or the secondary consumer through the lift cylinder operating unit and the secondary consumer operating unit of the main control valve unit, respectively. The energy reclaiming system includes: a working fluid return line provided with a flow amount limiting valve configured to interrupt a flow of a return flow amount generated by the lift cylinder when the working machine (or fork carriage) is lowered; and an energy reclaiming unit installed in the working fluid return line and configured to, if a return flow amount generated when the working machine is lowered is smaller than a flow amount consumed by the secondary consumer, reclaim the return flow amount to an oil tank, and, if the return flow amount generated when the working machine is lowered is larger than the flow amount consumed by the secondary consumer, guide the return flow amount to the hydraulic pump/motor. | 06-13-2013 |
20130055704 | Apparatus for Controlling Raise Speed of Working Machine for Heavy Equipment - The present disclosure relates to an apparatus for controlling a raise speed of a working machine for heavy equipment that includes first and second pumps, a main control valve unit that includes two lift cylinder operation units connected with the first and second pumps and operating two lift cylinders and one tilt cylinder operation unit operating two tilt cylinders, a priority valve that is provided in a working fluid line between the second pump and the main control valve unit, and a lift lever that includes a remote control valve connected with the two lift cylinder operation units through a pilot oil line, respectively, and controlling the two lift cylinders through the two lift cylinder operation units, in which a valve control unit, which electrically controls the flow of pilot oil in proportion to the RPM of an engine to allow or stop the working fluid flowing from any one of the two lift cylinder operation units to the two lift cylinders, is disposed in any one of two pilot oil lines between the two lift cylinder operation units and the remote control valve of the lift lever. | 03-07-2013 |