Abstract: A system and method for controlling engine revolutions for a hybrid construction machine, including an engine, a hydraulic pump which is driven by the engine to drive a hydraulic actuator with discharged hydraulic fluid, a motor-generator which is driven by the engine to generate electricity and to drive the hydraulic pump as a motor supplementing the engine, an energy storage device which is charged with electric energy generated by the motor-generator and which supplies the electric energy for motor operation of the motor-generator, a torque detection unit for detecting an output torque of the hydraulic pump that is required to drive the hydraulic actuator, and a hybrid control unit for controlling the motor operation of the motor-generator to supplement the engine output if the change of the output torque of the hydraulic pump exceeds a predetermined level and it is determined that an engine revolution drop will occur.

Abstract: A hydraulic control valve for heavy equipment is provided, which includes a valve body having a supply passage supplied with a hydraulic fluid from a hydraulic pump, ports for supplying the hydraulic fluid to an actuator or receiving the hydraulic fluid from the actuator, tank passages for returning the hydraulic fluid from the actuator to a hydraulic tank, and a first regeneration passage for supplying a part of the returned hydraulic fluid to the supply passage; a spool slidably installed in the valve body in accordance with supply of a pilot signal pressure from an exterior, and controlling flow of the hydraulic fluid supplied to the actuator from the supply passage during shifting; and a regeneration valve installed between the first regeneration passage and the tank passage, and including a piston moved by the hydraulic fluid from the hydraulic pump, a regeneration spool shifted by pressure fluctuation of the supply passage to variably adjust a flow rate of the hydraulic fluid discharged from the first r

Abstract: A swing system of a construction machine having a power generation function is provided. The construction machine includes a lower driving structure capable of traveling, an upper swing structure mounted on an upper portion of the lower driving structure and provided with a working device, a swing ring gear fixed to the lower driving structure, a swing ring gear cover fixed to the upper swing structure and engaged with the swing ring gear to perform a rotational operation, a permanent magnet installed on one of the swing ring gear and the swing ring gear cover, and an induction coil installed on the other of the swing ring gear and the swing ring gear cover. Induction current is generated in the induction coil in accordance with the rotational operation of the swing ring gear cover.

Abstract: An apparatus for shutting off a power supply for construction equipment or a vehicle driven by an engine, including a power supply, functional electrical devices connected to the power supply, a key switch managing the power supply, and a main relay applying or shutting off the power supply to the functional electrical devices in accordance with the state of the key switch, which includes a manipulation sensing means, a control relay installed between the key switch and the main relay to apply a key switch signal to a driving unit of the main relay if the electricity is not applied to its driving unit and to shut off the key switch signal to the driving unit of the main relay if the electricity is applied to its driving unit, and a controller receiving a manipulation signal from the manipulation sensing means and shutting off the power by driving the control relay if there is no manipulation signal for a predetermined time.

Abstract: A step apparatus for heavy construction equipment and tree harvester having a leveling system for controlling a horizontal level of a cab and an upper frame is provided, which includes a step protector including a main body fixedly installed on one side of an upper frame, a step guide hole opened from an inside of the main body to an outside, a guide rail formed along a length direction of an inner side wall of the main body, and an insert hole formed on one side of the guide rail and open toward a vertically upward direction of the guide rail; a side step including a plurality of foot steps arranged at specified intervals on a step frame to form stairs, a step drawer formed on an upper part of the step frame and seated in the step guide hole, and a guide pin positioned adjacent to the step drawer and projected toward the side wall of the main body, wherein when the guide pin is slid along the guide rail, the step frame is seated in the main body or is drawn out from the inside of the main body; and a folding

Abstract: A swing control system and method for a construction machine using an electric motor is provided. The swing control system includes a swing electric motor swinging an upper swing structure and a swing control unit.

Abstract: A negative control type hydraulic system in which the use of a pilot pump and a load pressure generator between a hydraulic pump and a control valve is not required to prevent a power loss.

Abstract: A step apparatus for heavy construction equipment and tree harvester having a leveling system for controlling a horizontal level of a cab and an upper frame is provided, which includes a step protector including a main body fixedly installed on one side of an upper frame, a step guide hole opened from an inside of the main body to an outside, a guide rail formed along a length direction of an inner side wall of the main body, and an insert hole formed on one side of the guide rail and open toward a vertically upward direction of the guide rail; a side step including a plurality of foot steps arranged at specified intervals on a step frame to form stairs, a step drawer formed on an upper part of the step frame and seated in the step guide hole, and a guide pin positioned adjacent to the step drawer and projected toward the side wall of the main body, wherein when the guide pin is slid along the guide rail, the step frame is seated in the main body or is drawn out from the inside of the main body; and a folding

Abstract: A hydraulic cylinder cushion device installed in a hydraulic cylinder provided, in which a rod performs reciprocating movement in a cylinder tube, and which discharges high-pressure hydraulic fluid that is formed in pressure chambers between a piston and a head cover and between the piston and a cover end during a stroke-end operation. The hydraulic cylinder cushion device includes a check ring which is installed in a groove provided on an inner surface of the head cover or the cover end, and moves to one side in the groove so as to close a flow path during rushing into a stroke end while it moves to the other side in the groove so as to open the flow path during an initial operation in the stroke end.

Abstract: A hydraulic circuit for an excavator is provided, which includes at least one first working device control valve having a first traveling control valve and a first boom control valve successively installed along a first center bypass line from a downstream side of a first hydraulic pump, at least one second working device control valve having a second traveling control valve and a second boom control valve successively installed along a second center bypass line from a downstream side of a second hydraulic pump, a third hydraulic pump providing fluid pressure to a swing motor installed on a third center bypass line, a swing control valve installed on a downstream side of the third hydraulic pump and shifted, in accordance with a valve switching signal input from the outside, to supply hydraulic fluid discharged from the third hydraulic pump to the swing motor, and a boom confluence line connected between an output port of the swing control valve and an input port of the boom control value to make the hydrauli

Abstract: A hydraulic system for construction equipment is provided, which can increase the driving speed of a corresponding working device by making hydraulic fluid of a hydraulic pump, which is added to the hydraulic system having two hydraulic pumps in the construction equipment, join hydraulic fluid on the working device side, and can intercept the supply of hydraulic fluid from the working device side to a traveling apparatus side when the working device and the traveling apparatus are simultaneously manipulated.

Abstract: A system and method for controlling engine revolutions for a hybrid construction machine is provided.

Abstract: A hydraulic system for construction equipment having a float function is provided. The hydraulic system can perform ground leveling as making a boom descend due to its own weight without using hydraulic fluid that is discharged from a hydraulic pump. The hydraulic system includes a holding logic poppet mounted in the float valve to prevent an abrupt descending of the boom due to leakage of the hydraulic fluid through a flow path between the main control valve and the float valve during the operation of the boom cylinders.

Abstract: Construction equipment having an electric control lever is provided, which can intercept a control signal applied to a flow control valve when trouble occurs in the electric control lever or a control unit.

Abstract: A hydraulic control valve is provided, which can prevent the occurrence of overload by relieving hydraulic fluid of a return line in which the overload occurs due to an inertial force of a rotator when a hydraulic motor that is operated by the hydraulic fluid supplied from a hydraulic pump stops halfway.

Abstract: A hood stay apparatus for an engine room in heavy construction equipment. The hood stay apparatus can safely keep an engine hood in an open state even if an external force is abruptly generated due to vibration, wind, and the like. The hood stay apparatus can also facilitate an opening/closing operation of the engine hood.

Abstract: A sliding door safety device for heavy construction equipment is provided, which includes an outer side wall having a doorway formed thereon, an upper rail and a lower rail formed on an upper part and a lower part of the outer side wall, respectively, a sliding door sliding to move to a front or rear side of a cab by an upper roller and a lower roller engaged with the upper rail and the lower rail, respectively, to open or close the doorway, and first and second door position sensing switches mounted on one side of the outer side wall to sense a door position when the door is in its open position where the door is fully opened or in its closed position where the door is fully closed.

Abstract: A leveling control system and method for heavy equipment, in which a lower frame having a traveling unit and an upper frame are combined together by a tilting unit, includes a sensor unit, provided in the equipment, for measuring twist angles of the lower frame and the upper frame against a reference horizontal surface and a traveling speed of the equipment, and detecting working state information of working devices; a control unit for receiving the twist angles, the traveling speed, and the working state information, calculating a correction angle for the leveling control of the upper frame, and generating a control signal for instructing an operation of an actuator in accordance with the correction angle; and a driving unit for performing the leveling through the actuator in accordance with the control signal received therein.

Abstract: A hydraulic flow sharing system for excavating and pipe laying work is provided, which can prevent the abrupt change of a traveling speed during traveling through compulsory sharing of the flow rate applied to a working device and a traveling apparatus when a combined operation, in which the traveling apparatus and the working device such as a boom are simultaneously driven, is performed.

Abstract: A pressure control valve is provided, which can variably control the set pressure of a relief valve in accordance with pilot signal pressure that is controlled in an operator's seat and so on when the set pressure of the relief valve required in a replaced working device is changed.