JP2012026245A - Construction machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction machinery capable of enhancing energy efficiency and saving labor by storing pressure oil energy as the potential energy of a counterweight.SOLUTION: In the construction machinery, the counterweight 14 is configured to be movable between a lifted position for storing potential energy and a downward standby position in the rear side of a revolving frame 4. Between the revolving frame 4 and the counterweight 14, a weight balance cylinder 18 is provided for moving the counterweight 14 between the lifted position and the standby position. Between the revolving frame 4 and a boom 8, a boom balance cylinder 13 is provided for expanding together with the boom cylinder 11 and moving the boom 8 upward/downward. Between the balance cylinders 13 and 18, a pressure oil circulation mechanism 25 is provided for circulating pressure oil between the balance cylinders by the potential energy when the counterweight 14 moves vertically.

Description

  The present invention relates to a construction machine such as a hydraulic excavator or a hydraulic crane, and more particularly to a construction machine suitably used for lifting and transporting loads such as earth and sand or scrap materials.

  Generally, a construction machine such as a hydraulic excavator is provided with a working device such as a boom and an arm on the front side of the revolving structure, and a counterweight on the rear side of the revolving structure to balance the weight of the entire revolving structure. It is said. This counterweight is normally fixedly provided on the rear side of the revolving structure (see, for example, Patent Document 1).

  In addition, the boom of the work device is provided with an arm that can be pivoted up and down at the tip side, and the counterweight is swung up and down following the movement of the arm at the rear end side of the boom. There is one that is configured to be movable so as to move (see, for example, Patent Document 2).

  However, the prior art disclosed in Patent Document 2 balances the movement of the center of gravity of the arm provided on the front end side of the boom by the movement of the center of gravity of the counterweight provided on the rear end side of the boom. It is not configured to store potential energy on the counterweight side by utilizing the expansion / contraction operation.

JP 2001-254386 A JP-A-10-60938

  By the way, in the above-described prior art, when the boom of the working device is moved up and down at the front of the revolving structure, pressure oil is supplied to and discharged from the hydraulic cylinder (hydraulic pump) to the boom cylinder. There is a problem in that the energy of the pressure oil is wasted because the rod is merely configured to expand and contract.

  That is, when the boom of the working device is swung downward, the weight of the entire working device is added in the direction of contraction of the boom cylinder, so that the pressure oil supplied to and discharged from the hydraulic source to the boom cylinder performs substantial work. There is a problem that the pressure oil energy is wasted in this case.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to store energy of pressure oil as potential energy of a counterweight, thereby improving energy efficiency and saving labor. It is to provide a construction machine.

  In order to solve the above-described problems, the present invention provides a revolving body provided on a base so as to be able to turn, a boom of a working device provided on a front portion of the revolving body so as to be able to be raised and lowered, and driven by a boom cylinder, The present invention is applied to a construction machine provided with a counterweight provided at a rear portion of the swivel body to balance the weight of the swivel body with respect to the working device.

  A feature of the configuration adopted by the invention of claim 1 is that the counterweight is movable between a rising position that rises upward on the rear side of the revolving structure and a standby position that is lowered downward, A weight moving actuator for moving the counterweight to the raised position and the standby position is provided between the swing body and the counterweight, and the boom cylinder and the boom cylinder are disposed between the swing body and the boom. A boom moving actuator that extends and retracts together to move the boom up and down is provided. Between the boom moving actuator and the weight moving actuator, a pressure that allows pressure oil to flow through a pipe line connecting the two. An oil distribution mechanism is provided, and the pressure oil distribution mechanism moves from the boom movement actuator to the weight movement actuator when the boom swings. The counterweight is moved to the raised position by circulating pressure oil through the pipe line toward the eta, and when the boom is lifted, the weight moving actuator is directed to the boom moving actuator via the pipe line. Thus, the counterweight is moved to the standby position by circulating the pressure oil.

  According to a second aspect of the present invention, the boom moving actuator and the weight moving actuator are each constituted by a hydraulic cylinder having a rod side oil chamber and a bottom side oil chamber, and the pressure oil circulation mechanism is A boom rod side pipe line connected to the rod side oil chamber of the boom movement actuator, a boom bottom side pipe line connected to the bottom side oil chamber of the boom movement actuator, and a rod of the weight movement actuator A weight rod side pipe connected to the side oil chamber, a weight bottom side pipe connected to the bottom side oil chamber of the weight moving actuator, and the boom rod side pipe to the weight rod side pipe The rod side pipe switching valve that communicates and shuts off, and the boom bottom side pipe communicates with and blocks the weight bottom side pipe. It has a configuration comprising a bottom side pipeline control valve for.

  According to a third aspect of the present invention, the counterweight is attached to the rear side of the revolving structure so as to be movable up and down, and is lifted upward from the frame of the revolving structure at the raised position. It is set as the structure mounted on the flame | frame of the said revolving body in the stand-by position.

  According to a fourth aspect of the present invention, the counterweight is attached to the rear side of the swinging body so as to be swingable upward and downward, and extends rearward from the frame of the swinging body at the raised position. In the standby position, it is configured to extend downward from the frame of the revolving structure.

  As described above, according to the first aspect of the present invention, when the boom moving actuator is contracted together with the boom cylinder to swing the boom, the pressure oil distribution mechanism is configured to discharge the pressure oil discharged from the boom moving actuator. Is guided to the weight moving actuator on the counter weight side through the conduit, so that the counter weight can be lifted to the ascending position by the weight moving actuator, and the potential energy can be stored at this time. When the boom moving actuator extends together with the boom cylinder to lift the boom, the boom moving actuator is driven in the extending direction by utilizing the potential energy of the counterweight stored by the weight moving actuator. can do.

  That is, the pressure oil distribution mechanism provided between the boom moving actuator and the weight moving actuator is configured so that the boom moving actuator is reduced from the boom moving actuator as the boom moving actuator is contracted when the boom swings. The pressure oil can be circulated toward the counter and the counterweight can be moved to the raised position. On the other hand, when the boom is lifted, the boom moving actuator can be driven in the extending direction until the counterweight moves to the standby position by circulating pressure oil from the weight moving actuator to the boom moving actuator. . Thereby, the speed when the boom is lifted can be increased, energy efficiency can be improved, and labor saving can be achieved.

  Therefore, when the boom of the working device is swung downward, the weight of the entire working device can be used as potential energy and converted to kinetic energy for lifting the counterweight to the raised position. On the other hand, when the boom of the working device is lifted upward, the potential energy stored on the count weight side by the weight moving actuator can be used as kinetic energy for driving the boom moving actuator in the extending direction. .

  According to a second aspect of the present invention, the boom moving actuator and the weight moving actuator are constituted by hydraulic cylinders each having a rod-side oil chamber and a bottom-side oil chamber. When the cylinder) is extended, the counterweight can be lifted to the raised position, and when it is reduced, the counterweight can be lowered to the standby position. Then, by switching both the rod side pipe switching valve and the bottom side pipe switching valve of the pressure oil circulation mechanism to the communication position, the rod side oil chamber of the boom moving actuator and the rod side oil chamber of the weight moving actuator And the bottom oil chamber of the boom moving actuator and the bottom oil chamber of the weight moving actuator can be communicated, and the movements of both actuators (hydraulic cylinders) can be linked. On the other hand, when each of the pipe switching valves of the pressure oil circulation mechanism is switched to the shut-off position, the actuators (hydraulic cylinders) can be shut off from each other. It can be moved up and down by the boom cylinder and the boom moving actuator.

  Further, according to the invention of claim 3, by attaching the counterweight to the rear side of the swinging body so that it can be moved up and down, the weight moving actuator has the counterweight from the frame of the swinging body to the upwardly raised position. In the standby position, the counterweight can be lowered to a position where the counterweight is placed on the frame.

  Further, in the invention of claim 4, the counterweight is attached to the rear side of the swinging body so as to be swingable in the upward and downward directions, so that the weight moving actuator can be moved to the raised position extending rearward from the frame of the swinging body. The counterweight can be swung so as to be lifted, and at the standby position, the counterweight can be swung so as to extend downward from the frame of the revolving structure. As a result, when the boom is swung downward on the front side of the revolving structure, the counterweight can be disposed on the rear side of the revolving structure at a raised position extending rearward from the frame, and the boom and the counterweight The moment can balance the weight before and after the swivel body.

1 is a front view showing a hydraulic excavator according to a first embodiment of the present invention. It is the side view which looked at the hydraulic excavator in FIG. 1 from back. It is sectional drawing which looked at the weight raising / lowering mechanism which raises / lowers a counterweight up and down from the arrow III-III direction in FIG. It is sectional drawing in the position similar to FIG. 3 which shows the state which lifted the counterweight to the raise position by the weight raising / lowering mechanism. FIG. 3 is a hydraulic circuit diagram for driving and controlling a boom cylinder, a boom balance cylinder, a weight balance cylinder, a solenoid valve, and the like. FIG. 6 is a hydraulic circuit diagram similar to FIG. 5 illustrating a state in which the boom is lifted by the boom cylinder and the boom balance cylinder. FIG. 6 is a hydraulic circuit diagram similar to FIG. 5 showing a state in which the regeneration mode is activated by switching the solenoid valve from the low pressure position to the high pressure position. FIG. 6 is a hydraulic circuit diagram similar to FIG. 5 illustrating a state in which the regeneration mode is activated and the boom is lifted. It is a flowchart which shows the selection and cancellation | release process of the reproduction | regeneration mode by a controller. FIG. 5 is a control block diagram including a controller that performs a playback mode selection / cancellation process. FIG. 10 is an electric circuit diagram for selecting and canceling a reproduction mode according to a second embodiment. It is a front view which shows the hydraulic shovel by 3rd Embodiment.

  Hereinafter, a construction machine according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where the construction machine is applied to a medium-sized hydraulic excavator called a so-called standard machine.

  Here, FIG. 1 to FIG. 10 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a hydraulic excavator as a construction machine. The hydraulic excavator 1 is a self-propelled lower traveling body 2 constituting a base, and is mounted on the lower traveling body 2 so as to be rotatable. In addition, the upper revolving unit 3 as a revolving unit constituting the vehicle body of the hydraulic excavator 1 and a work device 7 described later are roughly configured.

  Reference numeral 4 denotes a revolving frame constituting a frame of the upper revolving structure 3, and this revolving frame 4 is configured as a sturdy support structure formed by welding a plurality of steel plates or the like. On the revolving frame 4, a cab 5 that defines a cab is provided on the front side thereof, and on the rear side of the cab 5, for example, an engine (not shown), a hydraulic pump 21 described later, and the like are provided. The building cover 6 etc. accommodated in the inside are provided.

  Further, as shown in FIGS. 3 and 4, a weight mounting portion 4 </ b> A is provided on the rear side of the swivel frame 4, and the weight mounting portion 4 </ b> A is made of a plate material such as a steel plate having high rigidity. Are fixed by means such as welding. Here, the weight attaching portion 4A is formed as a pair of beams spaced apart in the left and right directions, for example, like the left and right vertical plates (not shown) of the revolving frame 4. And the inner tube 16 of the weight raising / lowering mechanism 15 mentioned later is being fixed to the rear end side of these weight attaching parts 4A by means, such as welding.

  Reference numeral 7 denotes a working device provided on the front side of the swing frame 4. The work device 7 includes a long boom 8 whose base end side is attached to the front portion of the swing frame 4 so as to be able to move up and down, and a tip of the boom 8. Arm 9 pivotably attached to the side, clamshell bucket 10 as a work implement pivotably provided on the tip side of the arm 9, and left and right for raising and lowering the boom 8 up and down A pair of boom cylinders 11 and a pair of left and right arm cylinders 12 for turning the arms 9 up and down are configured.

  The work device 7 rotates the boom 9 up and down by extending and retracting the boom cylinder 11 on the front side of the revolving frame 4, and rotates the arm 9 upward and downward by expansion and contraction of the arm cylinder 12. In this state, the working device 7 drives the clamshell bucket 10 to scoop up a load such as earth and sand, waste material, or scrap, and lifts and transports the load.

  Reference numeral 13 denotes a boom balance cylinder as a boom moving actuator provided between the revolving frame 4 and the boom 8. The boom balance cylinder 13 is constituted by a hydraulic cylinder as shown in FIGS. 1 and 5 to 8. Then, the boom 8 is expanded and contracted together with the boom cylinder 11 to move the boom 8 up and down. For this reason, the boom balance cylinder 13 has a function of reducing and reducing the load on the boom cylinder 11 by supporting the load (including its own weight) applied to the boom 8 in a shared manner with the boom cylinder 11.

  Here, as shown in FIG. 5, the boom cylinder 11 includes a tube 11A, a piston 11B that is slidably fitted in the tube 11A, one end fixed to the piston 11B, and the other end outside the tube 11A. It is comprised by the rod 11C which protruded. The piston 11B defines the inside of the tube 11A into a rod side oil chamber 11D and a bottom side oil chamber 11E.

  The boom balance cylinder 13 is configured similarly to the boom cylinder 11, and includes a tube 13A, a piston 13B, a rod 13C, a rod side oil chamber 13D, and a bottom side oil chamber 13E. When the boom balance cylinder 13 extends together with the boom cylinder 11, the boom 8 is lifted in the direction of arrow A in FIGS. 5 and 6, and the boom balance cylinder 13 contracts together with the boom cylinder 11. Sometimes the boom 8 is swung in the direction indicated by the arrow B.

  Reference numeral 14 denotes a counterweight provided on the rear end side of the revolving frame 4. The counterweight 14 balances the weight of the entire upper revolving unit 3 with respect to the work device 7 on the front side. Here, the counterweight 14 is moved up and down by a weight lifting mechanism 15 described later. For this reason, the counterweight 14 is moved between an ascending position that stores potential energy on the rear end side of the turning frame 4 and a standby position that descends downward.

  Reference numeral 15 denotes a weight raising / lowering mechanism, and the weight raising / lowering mechanism 15 is provided in the middle of the counterweight 14 in the width direction as shown in FIG. The outer tube 17 and a weight balance cylinder 18 which will be described later are included. As shown in FIGS. 3 and 4, the inner tube 16 is fixed at the lower end side to the rear end side of the weight mounting portion 4 </ b> A, and the upper end side extends upward (vertical direction) to become a free end.

  The outer tube 17 is formed of a cylindrical pipe that extends through the inside of the counterweight 14 in the height direction (upward and downward), and is integrated so as to form a part of the counterweight 14. The outer tube 17 is provided with its inner peripheral side inserted into the outer peripheral side of the inner tube 16 and is configured to slide and displace along the inner tube 16 together with the counterweight 14. Yes. The upper end of the outer tube 17 is a protruding portion 17A that protrudes from the upper surface of the counterweight 14, and both axial ends of a connecting pin 20 described later are attached to the protruding portion 17A in a locked state.

  Reference numeral 18 denotes a weight balance cylinder as a weight moving actuator that forms part of the weight lifting mechanism 15. The weight balance cylinder 18 is configured using a hydraulic cylinder in substantially the same manner as the boom cylinder 11, and has a tube 18A, a piston 18B, a rod 18C, a rod side oil chamber 18D, and a bottom side oil chamber 18E (see FIG. 5). ing. The weight balance cylinder 18 is inserted into the inner tube 16, and the bottom side of the tube 18 </ b> A is fixed to the lower end side of the inner tube 16 via a connecting pin 19.

  The upper end (projecting end) side of the rod 18 </ b> C is fixed to the projecting portion 17 </ b> A of the outer tube 17 via a connecting pin 20. In the weight balance cylinder 18, when pressurized oil is supplied into the bottom side oil chamber 18E, the rod 18C extends from the tube 18A, thereby raising the outer tube 17 upward along the inner tube 16 and increasing the counterweight. 14 is moved to the raised position shown in FIG. Further, when the rod 18C is contracted into the tube 18A, the outer tube 17 is slid downward along the inner tube 16, and the counterweight 14 is connected to the rear end side (for example, a weight mounting portion) of the swing frame 4. 4A) is lowered to a standby position (see FIG. 3).

  Reference numeral 21 denotes a hydraulic pump that constitutes a hydraulic power source together with the tank 22 shown in FIG. 5. The hydraulic pump 21 is rotationally driven by the engine provided in the building cover 6 of the upper swing body 3 shown in FIG. The hydraulic pump 21 pressurizes the hydraulic oil sucked from the tank 22 and discharges the pressure oil toward the boom cylinder 11 and the like.

  Reference numerals 23A and 23B denote a pair of main pipes provided between the boom cylinder 11, the hydraulic pump 21 and the tank 22. The main pipes 23A and 23B supply pressure oil from the hydraulic pump 21 to a boom control valve 24 which will be described later. The rod side oil chamber 11D and the bottom side oil chamber 11E of the boom cylinder 11 are supplied and discharged via the.

  Reference numeral 24 denotes a boom control valve composed of a direction control valve. The boom control valve 24 is located between the hydraulic pump 21, the tank 22 and the boom cylinder 11 and is provided in the middle of the main pipelines 23A and 23B. . The boom control valve 24 has, for example, hydraulic pilot portions 24A and 24B on both the left and right sides, and is supplied to the hydraulic pilot portions 24A and 24B when an operator operates an operation lever (not shown), for example. According to the pilot pressure, the neutral position (A) is switched to the left and right switching positions (B) and (C).

  When the boom control valve 24 is switched from the neutral position (A) to the switching position (B) as shown in FIG. 6, the pressure oil from the hydraulic pump 21 is sent to the bottom of the boom cylinder 11 via the main line 23B. The oil is supplied to the side oil chamber 11E, and the oil in the rod side oil chamber 11D is discharged toward the tank 22 from the main pipeline 23A side. Thereby, the rod 11C of the boom cylinder 11 extends so as to protrude from the tube 11A.

  On the other hand, when the boom control valve 24 is switched from the neutral position (A) to the switching position (C), the pressure oil from the hydraulic pump 21 is supplied to the rod side oil chamber 11D of the boom cylinder 11 via the main pipeline 23A. Then, the oil in the bottom side oil chamber 11E is discharged toward the tank 22 from the main pipeline 23B side. As a result, the rod 11C of the boom cylinder 11 is displaced so as to shrink toward the inside of the tube 11A.

  Reference numeral 25 denotes a pressure oil distribution mechanism employed in the present embodiment. The pressure oil distribution mechanism 25 is provided between the boom balance cylinder 13 and the weight balance cylinder 18 as shown in FIGS. When the regeneration mode is selected, both cylinders 13 and 18 are operated in conjunction with each other. At this time, the pressure oil circulation mechanism 25 switches a rod-side pipe switching valve 29 and a bottom-side pipe switching valve 31 described later to the communication position (b), so that the boom balance cylinder 13 and the weight balance cylinder 18 are connected to each other. A hydraulic closed circuit is formed between them.

  Here, the pressure oil distribution mechanism 25 includes a boom rod side pipe line 26A connected to the rod side oil chamber 13D of the boom balance cylinder 13 and a boom bottom side pipe connected to the bottom side oil chamber 13E of the boom balance cylinder 13. A path 26B, a weight rod side conduit 27A connected to the rod side oil chamber 18D of the weight balance cylinder 18, a weight bottom side conduit 27B connected to the bottom side oil chamber 18E of the weight balance cylinder 18, and The rod side pipe switching valve 29, the bottom side pipe switching valve 31, a solenoid valve 35, and the like are included.

  28A and 28B are a pair of branch pipelines, and the branch pipelines 28A and 28B constitute a part of the pressure oil circulation mechanism 25. Of these, the branch pipe 28A branches from the main pipe 23A between the boom cylinder 11 and the boom control valve 24, and extends to a position of a rod side pipe switching valve 29 described later. The branch pipeline 28B branches from the main pipeline 23B between the boom cylinder 11 and the boom control valve 24, and extends to a position of a bottom side pipeline switching valve 31 described later.

  Reference numeral 29 denotes a rod side pipe switching valve formed of a hydraulic pilot type directional control valve. The rod side pipe switching valve 29 has a hydraulic pilot section 29A, and is always arranged at an initial position (a) by a spring 29B. Yes. At this time, the rod side conduit switching valve 29 causes the boom rod side conduit 26A to communicate with the branch conduit 28A, and allows the weight rod side conduit 27A to communicate with the tank 22 via the tank conduit 30. For this reason, the boom rod side pipe line 26 </ b> A and the weight rod side pipe line 27 </ b> A are blocked from each other by the rod side pipe line switching valve 29.

  However, when the pilot pressure is supplied from the solenoid valve 35 described later to the hydraulic pilot portion 29A, the rod side pipe switching valve 29 is switched from the initial position (a) to the communication position (b) as shown in FIG. . At this time, the rod side pipe switching valve 29 causes the boom rod side pipe 26A and the weight rod side pipe 27A to communicate with each other and switches the branch pipe 28A and the tank pipe 30 to a closed state.

  Reference numeral 31 denotes a bottom side pipe switching valve composed of a hydraulic pilot type directional control valve. The bottom side pipe switching valve 31 has a hydraulic pilot portion 31A, and is always arranged at an initial position (a) by a spring 31B. Yes. At this time, the bottom side pipeline switching valve 31 communicates the boom bottom side pipeline 26B with the branch pipeline 28B and communicates the weight bottom side pipeline 27B with the tank 22 via the tank pipeline 32. For this reason, the boom bottom side pipe line 26 </ b> B and the weight bottom side pipe line 27 </ b> B are blocked from each other by the bottom side pipe line switching valve 31.

  However, when the pilot pressure is supplied from the solenoid valve 35 described later to the hydraulic pilot portion 31A, the bottom side pipe switching valve 31 is switched from the initial position (a) to the communication position (b) as shown in FIG. . At this time, the bottom side pipe switching valve 31 connects the boom bottom side pipe 26B and the weight bottom side pipe 27B to each other, and switches the branch pipe 28B and the tank pipe 32 to a closed state.

  33A and 33B are a pair of relief valves provided between the weight rod side pipe line 27A and the weight bottom side pipe line 27B. The relief valves 33A and 33B include the weight rod side pipe line 27A and the weight bottom side pipe line. When excessive pressure is generated in 27B, the valve is opened, and this pressure is relieved to the tank 22 side. Accordingly, the relief valves 33A and 33B have a function of preventing excessive pressure from being generated in the weight balance cylinder 18 and the like.

  Reference numeral 34 denotes a pilot pump as an auxiliary pump. The pilot pump 34 is driven to rotate together with the hydraulic pump 21 by the engine, and constitutes a pilot hydraulic source for the rod side pipe switching valve 29 and the bottom side pipe switching valve 31. To do.

  A solenoid valve 35 serves as a regeneration selection valve that supplies pilot pressure from the pilot pump 34 to the pilot pipe lines 36 and 37. The solenoid valve 35 is normally placed at a low pressure position (c) by a spring 35A, and keeps the pressure in the pilot lines 36 and 37 in a tank pressure state. However, when the regeneration selection switch 41 is operated as described later and the pressure oil circulation mechanism 25 is operated in the regeneration mode, the solenoid valve 35 is switched from the low pressure position (c) to the high pressure position (d).

  The solenoid valve 35 switched to the high pressure position (d) supplies the pilot pressure from the pilot pump 34 to the hydraulic pilot portion 29A of the rod side pipe switching valve 29 via the pilot pipe 36 and the pilot pipe 37. To the hydraulic pilot section 31A of the bottom side pipe switching valve 31. Therefore, the rod side pipe switching valve 29 and the bottom side pipe switching valve 31 are switched from the initial position (a) to the communication position (b), respectively, and between the boom balance cylinder 13 and the weight balance cylinder 18. Both cylinders 13 and 18 are operated in conjunction with each other so as to form a hydraulic closed circuit.

  38 is a limit switch for detecting the position of the boom 8. The limit switch 38 is disposed at a predetermined position as shown in FIGS. 5 to 8, and is opened until the boom 8 is lifted upward ( OFF). However, when the boom 8 is lifted up to a predetermined angle, the limit switch 38 is closed (ON).

  Reference numeral 39 denotes another limit switch for detecting the position of the counterweight 14. The limit switch 39 is disposed at a predetermined position as shown in FIGS. 5 to 8, and the counterweight 14 is lowered to the standby position. Sometimes it is in the closed (ON) state. However, when the counterweight 14 is moved upward from the standby position, the limit switch 39 is opened (OFF).

  Reference numeral 40 denotes a controller comprising a microcomputer or the like as control means. As shown in FIG. 10, the controller 40 has an input side connected to limit switches 38 and 39, a regeneration selection switch 41 and the like, and an output side thereof is a solenoid valve 35. And connected to the display 42 and the like. The controller 40 has a storage unit 40A composed of a ROM, a RAM, etc., and a processing program shown in FIG. 9 to be described later is stored in the storage unit 40A.

  The regeneration selection switch 41 is switched between an OFF (open) state and an ON (closed) state by manual operation by an operator in the cab 5, for example. During the open state, a later-described regeneration mode is invalidated. The When the regeneration selection switch 41 is closed, a regeneration mode described later is selected only when both the limit switches 38 and 39 are closed, and the boom balance cylinder 13 and the weight balance cylinder 18 are operated in conjunction with each other. The The display unit 42 displays, for example, whether the reproduction mode is selected in the control process by the controller 40 or whether the reproduction mode is invalidated.

  The hydraulic excavator 1 according to the present embodiment has the above-described configuration. Next, control processing by the controller 40 will be described with reference to FIG.

  First, when the processing operation starts, it is determined in step 1 whether or not the regeneration selection switch 41 is closed, and while it is determined “NO”, the regeneration selection switch 41 is opened. Moving to 2, the solenoid valve 35 is placed in the low pressure position (c). For this reason, the pressure in the pilot pipes 36 and 37 is reduced to substantially the same pressure as the tank pressure, and the rod side pipe switching valve 29 and the bottom side pipe switching valve 31 have returned to their initial positions (a). Is put into a state (see step 3).

  As a result, as shown in step 4, the boom balance cylinder 13 and the weight balance cylinder 18 are set in a state in which the mutual connection is released and the regeneration mode is invalidated. That is, as shown in FIGS. 5 and 6, the rod side pipe switching valve 29 at the initial position (a) connects the boom rod side pipe 26A to the branch pipe 28A and the weight rod side pipe 27A to the tank. It communicates with the tank 22 via the pipe line 30. The bottom side pipeline switching valve 31 at the initial position (a) communicates the boom bottom side pipeline 26B with the branch pipeline 28B and communicates the weight bottom side pipeline 27B with the tank 22 via the tank pipeline 32.

  Therefore, in the boom cylinder 11 and the boom balance cylinder 13, the rod side oil chambers 11D and 13D communicate with each other, and the bottom side oil chambers 11E and 13E communicate with each other. In this state, as shown in FIG. 6, when the boom control valve 24 is switched from the neutral position (A) to the switching position (B), the pressure oil from the hydraulic pump 21 flows through the bottom of the boom cylinder 11 via the main line 23B. While being supplied to the side oil chamber 11E, it is supplied to the bottom side oil chamber 13E of the boom balance cylinder 13 through the branch pipe 28B, and the oil in the rod side oil chambers 11D and 13D is supplied from the main pipe line 23A side to the tank 22. Discharge towards

  Thereby, the rod 11C of the boom cylinder 11 extends so as to protrude from the tube 11A, and the rod 13C of the boom balance cylinder 13 also extends so as to protrude from the tube 13A. As a result, the boom 8 is lifted upward by the boom cylinder 11 and the boom balance cylinder 13, and the lifting force of the load or the like by the work device 7 is increased to a total of four cylinders (two boom cylinders 11 and one or It can be increased by two boom balance cylinders 13). Thereafter, the process returns at step 5.

  On the other hand, when “YES” is determined in step 1, the regeneration selection switch 41 is closed and the regeneration mode is selected, so that the process proceeds to the next step 6 and the limit switch 38 on the boom 8 side is closed. It is determined whether or not. While it is determined as “NO” in step 6, the processes of steps 2 to 5 are repeated, and the boom 8 is lifted as shown in FIG. 6 and the limit switch 38 is closed.

  If “YES” is determined in Step 6, since the limit switch 38 is closed, the process proceeds to Step 7 to determine whether or not the limit switch 39 on the counterweight 14 side is closed. While it is determined as “NO” in step 7, the processes of steps 2 to 5 are repeated, and the process waits for the counterweight 14 to be lowered to the standby position as shown in FIG. The counterweight 14 is normally lowered to the standby position.

  When "YES" is determined in step 7, both the limit switches 38 and 39 are closed, and the boom 8 is lifted upward to a predetermined height position as shown in FIGS. The weight 14 is lowered to a predetermined standby position. As a result, a condition for operating the boom balance cylinder 13 and the weight balance cylinder 18 in the regeneration mode is established.

  Therefore, in this case, the process proceeds to step 8 where the solenoid valve 35 is switched from the low pressure position (c) to the high pressure position (d). As a result, the pilot pressure from the pilot pump 34 is supplied into the pilot pipes 36 and 37, and in step 9, the rod side pipe switching valve 29 and the bottom side pipe switching valve 31 are respectively in the initial positions (a). To the communication position (b). For this reason, as shown in step 10, the boom balance cylinder 13 and the weight balance cylinder 18 are set to the regeneration mode which is the “speed & fuel consumption priority mode”, and both are linked and operated.

  That is, in this state, when the operator switches the boom control valve 24 to the switching position (c) as shown in FIG. 7, the boom cylinder 11 receives the pressure oil from the hydraulic pump 21 via the main pipeline 23A. While being supplied to the chamber 11D, the oil liquid in the bottom side oil chamber 11E is discharged toward the tank 22 from the main pipeline 23B side. In addition, at this time, the weight of the boom 8 and the weight of the work device 7 as a whole are acting on the boom cylinder 11 in the reduction direction (the direction indicated by the arrow B in FIG. 7). 8 is swung down.

  For this reason, the boom balance cylinder 13 is also driven in the reduction direction, and the oil is discharged from the bottom side oil chamber 13E of the boom balance cylinder 13 toward the boom bottom side conduit 26B. This oil is supplied to the bottom side oil chamber 18E of the weight balance cylinder 18 through the bottom side pipe switching valve 31 and the weight bottom side pipe 27B which are switched to the communication position (b). Further, oil liquid is discharged from the rod side oil chamber 18D of the weight balance cylinder 18 toward the weight rod side pipe line 27A, and this oil liquid is switched to the communication position (b). Then, it is supplied to the rod side oil chamber 13D of the boom balance cylinder 13 through the boom rod side pipe line 26A.

  As a result, as the rod 13C of the boom balance cylinder 13 contracts, the weight balance cylinder 18 can extend upward from the tube 18A, lift the counterweight 14 to the raised position, and store potential energy. be able to. As described above, the rod-side pipeline switching valve 29 and the bottom-side pipeline switching valve 31 that are switched to the communication position (b) form a hydraulic closed circuit between the boom balance cylinder 13 and the weight balance cylinder 18. In this state, both cylinders 13 and 18 are operated in conjunction with each other.

  Further, in this state, when the operator switches the boom control valve 24 to the switching position (b) as shown in FIG. 8, the boom cylinder 11 receives the bottom oil from the hydraulic pump 21 via the main line 23B. While being supplied to the chamber 11E, the oil in the rod side oil chamber 11D is discharged toward the tank 22 from the main pipeline 23A side. At this time, the bottom oil chamber 13E of the boom balance cylinder 13 is connected to the bottom oil chamber 18E of the weight balance cylinder 18 via the weight bottom side conduit 27B, the bottom side conduit switching valve 31, and the boom bottom side conduit 26B. Pressure oil is supplied. From the rod side oil chamber 13D of the boom balance cylinder 13, the oil is discharged toward the rod side oil chamber 18D of the weight balance cylinder 18.

  For this reason, the rod 13C of the boom balance cylinder 13 is driven in the extending direction by the pressure oil supplied from the weight balance cylinder 18 side (that is, the potential energy of the counterweight 14 stored by the weight balance cylinder 18). 11, the boom 8 can be lifted upward (in the direction of arrow A in FIG. 7).

  Thus, when the boom balance cylinder 13 is extended together with the boom cylinder 11 and the boom 8 is lifted up with the regeneration mode selected, the potential energy of the counterweight 14 stored in advance by the weight balance cylinder 18 is used. By utilizing this, the boom balance cylinder 13 can be driven in the extending direction, whereby the speed when the boom 8 is lifted can be increased, energy efficiency can be increased, and labor saving can be achieved.

  That is, the pressure oil distribution mechanism 25 provided between the boom balance cylinder 13 and the weight balance cylinder 18 reduces the boom balance cylinder 13 when the boom 8 swings in the direction indicated by the arrow B. Pressure oil can be circulated from 13 to the weight balance cylinder 18 and the counterweight 14 can be moved to an elevated position where potential energy can be stored. On the other hand, when the boom 8 is lifted in the direction of arrow A, the boom balance cylinder 13 is moved until the counterweight 14 moves to the standby position by circulating pressure oil from the weight balance cylinder 18 toward the boom balance cylinder 13. It can be driven in the extending direction, and the lifting speed of the boom 8 can be increased.

  Therefore, when the boom 8 of the work device 7 is swung downward, the weight of the work device 7 as a whole can be utilized as potential energy and converted to kinetic energy for lifting the counterweight 14 to the raised position. On the other hand, when the boom 8 of the working device 7 is lifted upward, the potential energy stored on the count weight 14 side by the weight balance cylinder 18 is utilized as kinetic energy for driving the boom balance cylinder 13 in the extending direction. be able to.

  Next, in step 11 in FIG. 9, it is determined whether or not the regeneration selection switch 41 is closed. While determining “YES”, the processing from step 8 to 10 is repeated, and the boom balance cylinder 13 is repeated. And the weight balance cylinder 18 are operated in the regeneration mode. That is, setting is made so as to improve energy efficiency and save labor by utilizing the potential energy of the counterweight 14. On the other hand, if “NO” is determined in step 11, the reproduction selection switch 41 is opened, and thus the processing of steps 2 to 4 described above is performed. That is, at this time, the regeneration mode is invalidated, and the work mode is controlled with an emphasis on the lifting force of a load or the like by the work device 7.

  Thus, according to the present embodiment, when both the rod-side pipe switching valve 29 and the bottom-side pipe switching valve 31 of the pressure oil circulation mechanism 25 are disposed at the initial position (a) which is the shut-off position, It is possible to block the flow of pressure oil (hydraulic fluid) between the balance cylinder 13 and the weight balance cylinder 18. At this time, the boom 8 is connected to the boom cylinder 11 and the boom balance while the counterweight 14 is held at the standby position. The cylinder 13 can be lifted and lowered in a work mode in which the lifting force is emphasized.

  On the other hand, when the regeneration mode is selected by switching both the rod side pipe switching valve 29 and the bottom side pipe switching valve 31 of the pressure oil circulation mechanism 25 to the communication position (b), the rod side oil chamber of the boom balance cylinder 13 is selected. 13D can communicate with the rod side oil chamber 18D of the weight balance cylinder 18, and the bottom side oil chamber 13E of the boom balance cylinder 13 and the bottom side oil chamber 18E of the weight balance cylinder 18 can communicate with each other. 18 movements can be linked.

  As a result, when the boom 8 of the working device 7 is swung downward, the weight balance cylinder 18 is extended upward as the boom balance cylinder 13 is contracted, and the counterweight 14 is lifted to the raised position to increase the potential energy. Can be stored. On the other hand, when the boom 8 of the working device 7 is lifted upward, the potential energy stored on the count weight 14 side by the weight balance cylinder 18 is utilized as kinetic energy for driving the boom balance cylinder 13 in the extending direction. be able to.

  Therefore, according to the present embodiment, when the boom 8 of the working device 7 is swung downward, the energy of the pressure oil supplied from the hydraulic pump 21 is suppressed from being wasted, and the counterweight 14 side Can store potential energy. When the boom 8 is lifted, the boom balance cylinder 13 can be driven by utilizing the potential energy of the counterweight 14, so that energy efficiency can be improved and labor can be saved.

  Next, FIG. 11 shows a second embodiment of the present invention. In this embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted. Shall. However, the feature of the second embodiment resides in that the playback mode is selected and canceled using a relay circuit.

  That is, in the first embodiment, the controller 40 performs switching control of the solenoid valve 35. However, in the second embodiment, instead of the control means such as the controller 40, the switching control of the solenoid valve 35 is performed by an electric circuit using two relays 53 and 54 described later.

  In this case, the regeneration selection switch 41 includes a movable contact 41A that is manually switched by an operator, a common terminal 41B that is located on the proximal end side of the movable contact 41A, and a distal end side of the movable contact 41A that are switchably connected. 1 and second switching terminals 41C and 41D. The regeneration selection switch 41 is switched from the open (OFF) state to the closed (ON) state by switching the movable contact 41A from the switch terminal 41C to the switch terminal 41D side with the switch terminal 41D connected to the battery 51 as a power source. It is done.

  A lead wire 52 is provided between the common terminal 41 </ b> B of the regeneration selection switch 41 and the solenoid valve 35. This lead wire 52 is connected to the first wiring portion 52A provided between one terminal of the limit switch 38 on the boom 8 side and the common terminal 41B, the other terminal of the limit switch 38, and the counterweight 14. A second wiring portion 52B provided between one terminal of the limit switch 39 and a third wiring provided between the other terminal of the limit switch 39 and a relay coil 53A described later. 52C, a fourth wiring portion 52D provided between a relay coil 53A described later and a relay coil 54A described later, and a relay coil 54A described below and a solenoid valve 35. And a fifth wiring portion 52E.

  The lead wire 52 is connected between the first and second wiring portions 52A and 52B across the limit switch 38 on the boom 8 side, and terminals 53B and 53C of a relay 53 described later are provided in the middle position. A second parallel wiring section in which the second and third wiring sections 52B and 52C are connected across the wiring section 52F and the limit switch 39 of the counterweight 14 and terminals 54B and 54C of a relay 54 described later are provided at intermediate positions. 52G.

  53 is a first relay (relay) provided in parallel with the limit switch 38 on the boom 8 side. The first relay 53 is connected between the third and fourth wiring portions 52C and 52D of the lead wire 52. And a movable contact 53D that closes and opens the terminals 53B and 53C in accordance with energization (excitation) and non-energization (demagnetization) to the relay coil 53A.

  Here, in the first relay 53, when the terminals 53B and 53C are provided in the middle of the first parallel wiring portion 52F and the movable contact 53D is closed by energizing the relay coil 53A, the terminals 53B and 53C are connected. Keep conductive. For this reason, even if the limit switch 38 is opened in this state, the first relay 53 is electrically connected between the first and second wiring portions 52A and 52B of the lead wire 52 via the first parallel wiring portion 52F. Hold in the conductive state.

  Reference numeral 54 denotes a second relay (relay) provided in parallel with the limit switch 39 on the counterweight 14 side. The second relay 54 is connected between the fourth and fifth wiring portions 52D and 52E of the lead wire 52. And a movable contact 54D that closes and opens the terminals 54B and 54C in accordance with energization (excitation) and non-energization (demagnetization) to the relay coil 54A.

  Here, in the second relay 54, when the terminals 54B and 54C are provided in the middle of the second parallel wiring portion 52G, and the movable contact 54D is closed by energizing the relay coil 54A, the terminals 54B and 54C are connected. Keep conductive. For this reason, even if the limit switch 39 is opened in this state, the second relay 54 is electrically connected between the second and third wiring portions 52B and 52C of the lead wire 52 via the second parallel wiring portion 52G. Hold in the conductive state.

  Thus, also in the present embodiment configured as described above, an electric circuit including two relays 53, 54 and the like is used in place of the control means such as the controller 40 employed in the first embodiment. The switching control of the solenoid valve 35 can be performed, and the regeneration mode for operating the boom balance cylinder 13 and the weight balance cylinder 18 in conjunction with each other can be selected and released.

  That is, when the movable contact 41A of the regeneration selection switch 41 is switched from the switching terminal 41C to the switching terminal 41D and closed, the limit switches 38 and 39 are once closed and even if the limit switches 38 and 39 are opened thereafter, the relays 53 and 54 are closed. By keeping the closed state, the boom balance cylinder 13 and the weight balance cylinder 18 can be operated in the regeneration mode, and the potential energy of the counterweight 14 can be utilized to increase the energy efficiency and save labor.

  On the other hand, when canceling such a regeneration mode, the movable contact 41A of the regeneration selection switch 41 is returned to the switching terminal 41D side and opened, thereby deenergizing the relays 53 and 54 and placing the solenoid valve 35 in the high pressure position ( It is possible to return to the low pressure position (c) from d). At this time, the regeneration mode is invalidated, and the work mode can be controlled with an emphasis on the lifting force of the load or the like by the work device 7.

  Next, FIG. 12 shows a third embodiment of the present invention. The feature of the present embodiment is that the swing body of the excavator is arranged at a high position using a support column as a base. is there. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, reference numeral 61 denotes a hydraulic excavator as a construction machine. The hydraulic excavator 61 is configured in substantially the same manner as the hydraulic excavator 1 described in the first embodiment, and includes an upper swing body 62 and a working device as a swing body. 7. However, the upper swing body 62 in this case is different from the first embodiment in that the upper swing body 62 is disposed at a high position using the support column 63 serving as a base.

  Reference numeral 64 denotes a revolving frame constituting a frame of the upper revolving structure 62. This revolving frame 64 is configured in substantially the same manner as the revolving frame 4 described in the first embodiment, and on the revolving frame 64, the cab 5, A building cover 6 and the like are provided. However, a weight mounting portion 64A is provided on the rear side of the turning frame 64 so as to protrude rearward as a support bracket that supports a counterweight 65, which will be described later, so as to be swingable upward and downward. Further, a cylinder mounting portion 64B is provided on the lower surface side of the revolving frame 64 so as to protrude downward, to which a bottom side of a weight balance cylinder 66 described later is rotatably connected.

  Reference numeral 65 denotes a counterweight provided on the rear end side of the revolving frame 64. The counterweight 65 is configured in substantially the same manner as the counterweight 14 described in the first embodiment, and is different from the work device 7 on the front side. Thus, the weight balance of the entire upper swing body 62 is achieved. However, the counterweight 65 is swingably connected to the weight mounting portion 64A of the revolving frame 64 and is moved up and down by a weight balance cylinder 66 described below.

  For this reason, the counterweight 65 extends upward on the rear end side of the revolving frame 64 as shown by a solid line in FIG. 12 and stores it in a downward direction as shown by a two-dot chain line in FIG. It is moved between the standby position lowered. In this standby position, the counterweight 65 is pivoted downward from the weight mounting portion 64A of the swivel frame 64 and extends substantially vertically downward.

  Reference numeral 66 denotes a weight balance cylinder as an actuator for moving the weight. The weight balance cylinder 66 is configured by using, for example, a hydraulic cylinder in substantially the same manner as the boom cylinder 11, and its bottom side is connected to the cylinder mounting portion 64 </ b> B of the revolving frame 64. 67 etc., it is connected so that rotation is possible. Further, the weight balance cylinder 66 is rotatably connected to the counterweight 65 on the rod side using a connection pin 68 or the like.

  The weight balance cylinder 66 lifts the counterweight 65 to the ascending position with the maximum extension as shown by the solid line in FIG. 12, and at this time the counterweight 65 stores potential energy on the rear end side of the swivel frame 64. It extends toward the back. When the weight balance cylinder 66 is reduced, the counterweight 65 is lowered to the standby position as indicated by a two-dot chain line in FIG. 12, and at this time, the counterweight 65 is suspended from the weight mounting portion 64A of the swivel frame 64. So as to extend downward.

  Here, as with the weight balance cylinder 18 described in the first embodiment, the weight balance cylinder 66 is connected to the rod side pipe switching valve 29 via the weight rod side pipe 27A, and the weight bottom side pipe It is connected to the bottom side pipeline switching valve 31 via the channel 27B (see FIGS. 5 to 8).

  Thus, also in the present embodiment configured as described above, by switching the rod side pipe switching valve 29 and the bottom side pipe switching valve 31 to the communication position (b) as in the first embodiment. If the regeneration mode is selected, the boom balance cylinder 13 and the weight balance cylinder 66 can be operated in tandem with each other, and the potential energy of the counterweight 14 can be utilized to improve energy efficiency and save labor.

  In particular, in the third embodiment, the upper swing body 62 is pivotably provided on the support 63 and is arranged at a high position. Therefore, for example, than the hydraulic excavator 1 described in the first embodiment. Transport work and the like at a high place can be performed more efficiently. Further, when the boom 8 of the working device 7 is lifted up and down on the front side of the swing frame 64, the counterweight 65 on the rear end side is swung upward and downward to balance the weight of the entire upper swing body 62. Can be secured satisfactorily.

  In the first embodiment, the weight elevating mechanism 15 that elevates and lowers the counterweight 14 using the two weight balance cylinders 18 has been described as an example. However, the present invention is not limited to this, and the counterweight may be raised and lowered using, for example, one weight balance cylinder or three or more weight balance cylinders. The second embodiment may also be configured to use a plurality of weight balance cylinders.

  On the other hand, in each said embodiment, the case where the clamshell bucket 10 as a working tool was attached to the arm 9 of the working device 7 was mentioned as an example, and was demonstrated. However, the present invention is not limited to this. For example, a gripping device (gripping tool) such as waste material, scrap, or wood, a crusher such as a breaker, an excavator, or a work tool such as a backhoe type bucket is attached to the tip of the arm 9. It is good also as a structure provided in the side.

  Further, the application object of the present invention is not necessarily limited to the hydraulic excavator. For example, the present invention is also applicable to various construction machines in which a working device is provided on the front side of the revolving structure and a counterweight is provided on the rear end side. It can be done. Further, the prime mover of the construction machine is not limited to the engine, and for example, an electric motor may be used as the prime mover.

  Further, in the first embodiment, the case where the weight moving actuator is constituted by the weight balance cylinder 18 made of a hydraulic cylinder and the counterweight 14 is moved up and down has been described as an example. However, the present invention is not limited to this. For example, a weight moving actuator is constituted by a hydraulic motor, and a weight raising / lowering mechanism is constituted so as to convert the rotation of the hydraulic motor into upward and downward movement of the counterweight 14. Is also good. This is the same for the second embodiment.

1,61 Hydraulic excavator (Construction machinery)
2 Lower traveling body (base)
3,62 Upper swing body (swivel body)
4,64 swivel frame 4A, 64A weight attachment portion 5 cab 7 working device 8 boom 9 arm 10 clamshell bucket (working tool)
11 Boom cylinder 12 Arm cylinder 13 Boom balance cylinder (actuator for moving the boom)
14, 65 Counterweight 15 Weight lifting mechanism 16 Inner tube 17 Outer tube 18, 66 Weight balance cylinder (actuator for weight movement)
21 Hydraulic pump (hydraulic power source)
22 Tank 25 Pressure oil distribution mechanism 26A Boom rod side pipe 26B Boom bottom side pipe 27A Weight rod side pipe 27B Weight bottom side pipe 28A, 28B Branch pipe 29 Rod side pipe switching valve 31 Bottom side pipe switching Valve 34 Pilot pump 35 Solenoid valve 38 Boom side limit switch 39 Counterweight limit switch 40 Controller (control means)
41 Playback selection switch (position detection means)
53, 54 Relay 63 Post (base)

Claims (4)

A revolving body provided on the base so as to be capable of swiveling; a boom of a working device provided on a front portion of the revolving body so as to be movable up and down and driven by a boom cylinder; and On the other hand, in a construction machine comprising a counterweight that balances the weight of the swivel body,
The counterweight is configured to be movable between a rising position that rises upward on the rear side of the revolving structure and a standby position that is lowered downward,
Provided between the swivel body and the counterweight is a weight moving actuator that moves the counterweight to the raised position and the standby position;
Between the swivel body and the boom, provided is a boom moving actuator that extends and contracts together with the boom cylinder to move the boom up and down,
Between the boom moving actuator and the weight moving actuator, there is provided a pressure oil distribution mechanism for distributing pressure oil through a pipe line connecting the two,
The pressure oil circulation mechanism moves the counterweight to the raised position by causing pressure oil to flow from the boom moving actuator to the weight moving actuator toward the weight moving actuator when the boom swings, Construction wherein the counterweight is moved to a standby position by circulating pressure oil from the weight moving actuator to the boom moving actuator through the conduit when the boom is lifted. machine. The boom moving actuator and the weight moving actuator are each constituted by a hydraulic cylinder having a rod side oil chamber and a bottom side oil chamber,
The pressure oil circulation mechanism includes a boom rod side conduit connected to the rod side oil chamber of the boom moving actuator, a boom bottom side conduit connected to the bottom oil chamber of the boom moving actuator, The weight rod side conduit connected to the rod side oil chamber of the weight moving actuator, the weight bottom side conduit connected to the bottom oil chamber of the weight moving actuator, and the boom rod side conduit are connected to the weight A rod-side pipeline switching valve that communicates with and shuts off the rod-side pipeline, and a bottom-side pipeline switching valve that communicates and blocks the boom bottom pipeline with the weight bottom pipeline. The construction machine according to claim 1.   The counterweight is attached to the rear side of the revolving structure so as to be movable up and down, lifted upward from the frame of the revolving structure at the raised position, and on the revolving structure frame at the standby position. The construction machine according to claim 1, wherein the construction machine is configured to be placed.   The counterweight is attached to the rear side of the swing body so as to be swingable upward and downward, and extends backward from the frame of the swing body in the raised position, and downward from the frame of the swing body in the standby position. The construction machine according to claim 1, wherein the construction machine is configured to extend toward the front.

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