Abstract: A system and method of controlling torque of plural variable displacement hydraulic pumps in construction equipment are provided, which can control torque of the variable displacement hydraulic pumps so that the total amount of torque of the hydraulic pumps does not exceed the preset amount of torque by presetting the torque so that the engine does not stop even at maximum load of the hydraulic pumps or by presetting the speed of the engine or the used torque of the hydraulic pumps in consideration of the fuel economy or working speed.

Abstract: An engine revolution speed control system for a construction machine is disclosed. The engine revolution speed control system includes an input unit that sets an engine revolution speed by a user, outputs a setting process as a set signal, and determines whether or not an engine is driven at a set engine revolution speed; a control unit that receives the set signal and stores the set engine revolution speed, receives the set signal and an ON/OFF signal to output an output signal corresponding to the received set signal and the ON/OFF signal, and controls operation of the engine at the set engine revolution speed in accordance with the ON/OFF signal; and a display that receives the output signal to visually output the setting process or whether or not the engine is driven at the set engine revolution speed.

Abstract: Construction equipment including a hydraulic pump driven by an engine, a lower driving structure, an upper swing structure swingably mounted on the lower driving structure, a working device mounted on the upper swing structure and having a boom, an arm, and a bucket respectively driven by a hydraulic cylinder is disclosed. The construction equipment comprises a rear view camera to permit a driver to view rearward traffic conditions.

Abstract: A traveling system for construction equipment is provided, which can secure an initial traveling manipulability regardless of a low-speed traveling or a high-speed traveling. If the high-speed traveling is selected and the traveling is manipulated, the inclination angle of a swash plate of a hydraulic pump is variably controlled, so that the discharge flow rate of the hydraulic pump exceeds a predetermined flow rate in comparison to the low-speed traveling.

Abstract: An apparatus for cooling overheated gas generated from a diesel particulate filter which is connected between a diesel engine and an exhaust pipe of the diesel engine is disclosed. The apparatus includes a tail pipe for discharging outwardly the overheated gas discharged from the diesel particulate filter, a cooling fan, provided at one side of an engine room, for generating an air stream by sucking ambient air, and a diffuser enclosing an outer circumference of the tail pipe in such a way a space is formed between the diffuser and the tail pipe to prevent the diffuser from directly contacting the tail pipe. The engine room is provided with a through-hole penetrating one side of the engine room, and the tail pipe has one end connected to the diesel particulate filter, and the other end extended outwardly from the engine room through the through-hole.

Abstract: A traveling and turning device for a construction machine is provided, which includes a left driving motor and a right driving motor driven by hydraulic fluid, a left main control valve and a right main control valve controlling movement of the left driving motor and the right driving motor, respectively, and a left pedal and a right pedal adjusting the operation state of the left main control valve and the right main control valve, respectively.

Abstract: A shock absorption device and a control method thereof for a small swing radius (SSR) excavator are provided, which can relieve shock generated on a boom cylinder by controlling only the discharge flow rate of hydraulic pumps, being supplied to the boom cylinder, even without controlling a main control valve when a boom of the excavator ascends at its maximum height through manipulation of a control level.

Abstract: An image display system for controlling automatic leveling of heavy equipment is provided. The image display system includes the leveling means for adjusting horizontal levels of a lower frame provided with a traveling means and an upper frame having a cab and installed on an upper part of the lower frame, a sensor unit for sensing posture information of the heavy equipment, a leveler electronic control unit for generating an image signal from the posture information, and an image display unit for displaying the image signal on a display screen. The posture information includes inclination angles of the upper frame and the lower frame sensed on the basis of a horizontal surface against a direction of gravity, an azimuth angle of the heavy equipment sensed against a forward direction of the upper frame, and a swing angle of the upper frame sensed on the basis of a front direction of the lower frame.

Abstract: An engine room for construction equipment is provided, which can minimize emission of noise generated in an engine room due to driving of an engine and a ventilating fan to an outside of the engine room by absorbing the noise through a noise trap, and can improve the cooling performance of corresponding components by smoothing inhalation/discharge of an external air to/from the airtight engine room.

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. The system 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 system and method for controlling automatic leveling heavy construction equipment. The system has a lower frame and an upper frame, the lower frame having a traveling unit, and the upper frame being tiltably and swingably connected to the lower frame. The system comprises a sensor unit, provided in the equipment, including an inclination detecting sensor for measuring twist angles of the lower frame and the upper frame against a reference horizontal surface, a traveling detection sensor for measuring a traveling speed of the equipment, and a working device sensor for detecting working state information of a working device. A control unit receives the twist angles, the traveling speed, and the working state information, calculates a corrected angle at which the upper frame is to be tilted against the lower frame, and generates a control signal for instructing an operation of an actuator. A driving unit performs a leveling control through the actuator in accordance with the received control signal.

Abstract: A traveling device for crawler type heavy equipment is provided, which can improve manipulability by preventing an abrupt decrease/increase of a traveling speed of the equipment when a combined operation, in which a left/right traveling device and a working device are simultaneously driven, is performed. The traveling device for crawler type heavy equipment includes a variable orifice shifted to intercept the supply of the hydraulic fluid toward the traveling device in response to the signal pressure in the combined working mode if a load pressure of the working device is relatively higher than that of the traveling device.

Abstract: A hydraulic circuit having a holding valve of an external pilot pressure operation type is provided, which can make a double check valve, which is installed to prevent an actuator from being pushed due to leakage of hydraulic fluid of a main control valve, be opened by an external signal pressure being supplied to shift the main control valve. The hydraulic circuit includes a double check valve installed in a flow path between the main control valve and the hydraulic cylinder to be opened by the pilot signal pressure for shifting the main control valve, and preventing the hydraulic cylinder from being moved due to leakage of hydraulic fluid of the main control valve, and a select valve shifted to open the double check valve in response to the pilot signal pressure being supplied in accordance with the manipulation of the joystick.

Abstract: A system and method for controlling an automatic leveling of heavy equipment. The system, 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 sensing twist angles of the lower frame and the upper frame against a reference horizontal surface and a traveling speed of the equipment. A control unit receives the twist angles and the traveling speed, sets a limit of an operation time for the automatic leveling in a standstill state of the equipment while calculating a corrected angle to which a twist angle of the upper frame is to be corrected, without setting the limit of the operation time for the automatic leveling, in a traveling state of the equipment, and generates a control signal for instructing an operation of a tilting unit in accordance with the corrected angle. A driving unit performs a tilting control through the tilting unit in accordance with the received control signal.

Abstract: A hydraulic circuit of an option device for an excavator is disclosed, which can constantly supply hydraulic fluid to an option device, such as a breaker and so on, selectively mounted on the excavator, irrespective of the size of a load occurring when the option device operates, and control respective flow rates required for various kinds of option devices. The hydraulic circuit includes a variable hydraulic pump, an option device, a first spool shifted to control hydraulic fluid fed to the option device, a poppet and a piston, an option spool shifted to control hydraulic fluid fed to the option device via the first spool, a second spool shifted to control hydraulic fluid fed to a back pressure chamber of the poppet, and a control means installed in the poppet and controlling hydraulic fluid passing through an orifice of the poppet when the piston and the poppet are pressed by the hydraulic fluid fed from the hydraulic pump, through the shifting of the second spool.

Abstract: An antitheft system and method for construction equipment is disclosed. The antitheft system and method can prevent the construction equipment from driving if a driver gets out of a cabin in the state in which an ignition is turned on so as to preheat a heater or engine or in a case where a driving unit is not manipulated during a predetermined period.

Abstract: A hydraulic circuit for preventing a change of stroke of a boom cylinder or an arm cylinder during transportation. The hydraulic circuit includes first and second hydraulic pumps, a boom cylinder, an arm cylinder, a boom confluence logic valve, a first port connected with a chamber of the boom cylinder in a housing in which a spool for the boom cylinder is shiftably installed, a second port connected with a hydraulic tank in the housing, and a first orifice formed between the housing and a land part of the spool for the boom cylinder located between the first port and the second port. During transportation, a small amount of hydraulic fluid fed from the second hydraulic pump to the large chamber of the boom cylinder drains to the hydraulic tank through the first orifice to prevent a change of stroke of the boom cylinder.

Abstract: A hydraulic circuit for heavy equipment is provided, which can prevent signal pressure exceeding a predetermined pressure from being formed in a pilot signal path provided in a switching valve to sense whether the switching valve has been shifted in a hydraulic system that minimizes the discharge flow rate of a hydraulic pump when a working device such as a boom is not driven.

Abstract: A seat for heavy equipment having a buffer in forward and backward directions, which can protect an operator by attenuating impact and vibration generated in a cab in forward and backward directions of an excavator in accordance with the driving of the buffer in a main working mode of the excavator. The seat includes a lower member mounted on a suspension plate, an upper member slidably mounted on the lower member in forward and backward directions of the equipment, a buffer unit for attenuating impact and vibration generated in the forward and backward directions of the equipment, a tilting unit, and a locking unit. In a main working mode, a buffer function is performed through forward and backward movement of the upper member against the lower member, and when the main working mode is released, the buffer function is released.

Abstract: An arrangement for reducing a rotational speed of a rotating member includes a first and second pressure member arranged at a distance from each other and an opposite sides of the rotating member for movement relative to each other between a retracted position and a forward position engaging the rotating member. The arrangement includes an adjustment device including a friction structure forming a friction joint with one of the pressure members for maintaining a position relative to one another provided a maximum friction force is not exceeded. The arrangement further includes a spring acting on the friction structure for separating the pressure members after having been compressed. The spring has a gradually increasing spring force between a non-compressed state and a totally compressed state.