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: 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 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 rain hat device for heavy construction equipment which is installed adjacent to an exhaust gas discharging port of a distal end portion of an exhaust pipe to prevent inflow of rainwater therein is disclosed. The rain hat device comprises a swing cover installed at a distal end portion of the exhaust pipe in a spaced and floated state so as to prevent rainwater from flowing in the distal end portion of the exhaust pipe, and in which the swing cover does not come into contact with the distal end portion of the exhaust pipe to prevent noise from being generated due to contact and collision when an engine stops or exhaust gas is not discharged.

Abstract: An exhaust cooling apparatus for construction equipment, having a cooling fan taking external air into an engine room for heat exchange with a oil cooler and a radiator, and a blower flowing air out of the engine room to the atmosphere. In the apparatus, an outlet of an exhaust pipe for emitting exhaust gas from an engine is fixedly disposed toward a discharge direction of the blower. The discharge direction of the blower is upwardly vertical to the ground. The exhaust cooling apparatus is effective in preventing combustible matters from burning, or preventing plant lives from withering, due to hot exhaust gas around construction equipment such as excavator, by discharging the hot exhaust gas to the atmosphere after cooling it down through air flowing out of the engine room.

Abstract: A footstep for an excavator is provided, in which the footstep, that is fixed to a track side frame so that an operator can get on/off a cab and so on therethrough, can be prevented from being damaged by rocks and so on during operation of the excavator in an inferior working environment. The footstep for an excavator, mounted on a track side frame of the excavator, includes an upper step composed of side plates formed on left and right sides to face each other, and a front plate formed in a body with the side plates and having through-holes formed on left and right sides thereof, to protect a head part of a fastening member, which fixes the footstep to the side frame, from an external impact; a fixing plate having both ends fixed to inner surfaces of the side plates to fix the upper step to the side frame by the fastening member that is fastened to pass through the through-holes; and a lower step fixed to lower ends of elastic pieces having upper ends fixed to the side plates, respectively.

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 noise silencer for construction equipment is used to minimize outward propagation of noises generated from an engine room. The noise silencer is mounted in air intake and/or discharge openings of an engine room, and includes a frame mounted in the one of the air intake and discharge openings of the engine room, and noise damping members fixed to the frame at uniform intervals, and each including a first member, which is disposed inside the engine room in a horizontal direction such that cooling air introduced from outside to inside of the engine room by operation of a cooling fan smoothly flows, and a second member, which is integrally formed with the first member and is disposed outside the engine room so as to be inclined upwardly at a predetermined inclination.

Abstract: A hydraulic circuit for an excavator is provided, which includes first to third hydraulic pumps, a first traveling control valve and a first boom control valve successively installed along a first center bypass line from a downstream side of the first hydraulic pump, a second traveling control valve and a second boom control valve successively installed along a second center bypass line from a downstream side of the second hydraulic pump, a swing control valve connected between the third hydraulic pump and a swing motor to control the operation of the swing motor in accordance with an external valve switching signal, and a confluence line connected between a third center bypass line and a flow path of the second boom control valve to make hydraulic fluid from the third hydraulic pump join hydraulic fluid in a neutral position of the swing control valve.

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: An apparatus for increasing an operation speed of a boom on excavators is disclosed, which enables an unskilled operator to conveniently manipulate a working device by decreasing a rotation speed and increasing a lifting speed relatively when the excavator performs combined operation of boom lift and swing drive to improve its working efficiency. The apparatus includes first and second hydraulic pumps, a first actuator, a pair of second actuators, first to third control valves, a block valve installed in a flow path between the selected second actuator and the second control valve, supplying the hydraulic fluid from a second hydraulic pump to the selected actuator only when the second actuators are driven to be switched according to a control signal of boom lift at combined operation in which the first and second actuators are simultaneously driven, to replenish the first actuator with the hydraulic fluid to be supplied to the second actuator.

Abstract: A hydraulic circuit for heavy construction equipment to reduce a speed of a swing apparatus while a working apparatus such as a boom is concurrently operated has a work control valve which controls a working apparatus cylinder; a confluence valve which combines a hydraulic fluid of the second hydraulic pump with the work unit flow path based on a positions switch; a swing control valve which controls the hydraulic swing motor; and a disconnection valve which disconnects the hydraulic fluid supplied to at least one of the swing motors.

Abstract: A heating apparatus for a cabin of a construction equipment in which hot air ejected from an oil cooler is used for heating in the winter while it is ejected out in the summer, to maximize cooling or heating efficiency of the cabin of the construction equipment. The heating apparatus for a cabin of a construction equipment includes a duct ejecting air ejected from an oil cooler provided inside an automotive body at the rear of the cabin to the outside of the automotive body, and a switching unit provided in the duct to open and close an air vent in the duct, guiding the air inside the duct to the rear of the cabin if it is opened. The heating apparatus is automatically operated depending on its peripheral temperature condition to maximize cooling or heating efficiency of the cabin.

Abstract: A lubricant recovering apparatus is disclosed, which can process lubricant collected in a drain pipeline due to an oil slobbering phenomenon occurring in a diesel engine. The lubricant recovering apparatus includes a tail pipe connected to an engine of the heavy construction equipment for discharging an exhaust gas, a tap installed at a bottom point of the tail pipe, a first pipe connected to the tap at one end thereof, a joint member detachably connected to the other end of the pipe, a second pipe mounted on a lower end of the joint member and extending to an interior of an oil reservoir, a penetrating portion having a hole formed on an upper portion of the oil reservoir, through which the tail pipe passes, and a drain port formed on a lower end of the second pipe penetrating the penetrating portion and having a mesh.

Abstract: A rain hat for heavy construction equipment is disclosed, which comprises a plate which corresponds to a shape of an outlet of the exhaust tube; a connection part which is formed at one end of the plate and is extended in a downward direction; and an elastic plate of which one end is connected with the connection part, and the other end is engaged with the exhaust tube, said elastic plate having a certain length, whereby the outlet of the exhaust tube, which is closed by means of the plate, opens as a discharge pressure overcomes an elastic force of the elastic plate when exhaust gas is discharged from the exhaust tube.

Abstract: A lubricant recovering apparatus is disclosed, which can process lubricant collected in a drain pipeline due to an oil slobbering phenomenon occurring in a diesel engine. The lubricant recovering apparatus includes a tail pipe connected to an engine of the heavy construction equipment for discharging an exhaust gas, a tap installed at a bottom point of the tail pipe, a first pipe connected to the tap at one end thereof, a joint member detachably connected to the other end of the pipe, a second pipe mounted on a lower end of the joint member and extending to an interior of an oil reservoir, a penetrating portion having a hole formed on an upper portion of the oil reservoir, through which the tail pipe passes, and a drain port formed on a lower end of the second pipe penetrating the penetrating portion and having a mesh.

Abstract: An apparatus for increasing an operation speed of a boom on excavators is disclosed, which enables an unskilled operator to conveniently manipulate a working device by decreasing a rotation speed and increasing a lifting speed relatively when the excavator performs combined operation of boom lift and swing drive to improve its working efficiency. The apparatus includes first and second hydraulic pumps, a first actuator, a pair of second actuators, first to third control valves, a block valve installed in a flow path between the selected second actuator and the second control valve, supplying the hydraulic fluid from a second hydraulic pump to the selected actuator only when the second actuators are driven to be switched according to a control signal of boom lift at combined operation in which the first and second actuators are simultaneously driven, to replenish the first actuator with the hydraulic fluid to be supplied to the second actuator.

Abstract: A hydraulic circuit for heavy construction equipment to reduce a speed of a swing apparatus while a working apparatus such as a boom is concurrently operated has a work control valve which controls a working apparatus cylinder; a confluence valve which combines a hydraulic fluid of the second hydraulic pump with the work unit flow path based on a positions switch; a swing control valve which controls the hydraulic swing motor; and a disconnection valve which disconnects the hydraulic fluid supplied to at least one of the swing motors.

Abstract: A cylinder cushion device is provided for a hydraulic cylinder of an excavator, to prevent a piston from colliding with an end boss and absorb shock due to collision. Pressure higher than design strength of the hydraulic cylinder does not occur even if external force is given to the hydraulic cylinder. The cylinder cushion device includes a tube constituting a receiving chamber of hydraulic oil, a rod performing straight line motion, a piston fixed onto the rod and dividing the receiving chamber of the tube, an end boss, a cushion sleeve provided on the rod to be adjacent to the piston, for generating a predetermined cushion pressure inside the rod-side chamber if the piston is adjacent to the end boss during straight line motion of the rod, and an elastic body provided on the cushion sleeve for preventing the piston from colliding with the end boss and absorbing shock by means of its elasticity.