Excavation machine operating device and excavation machine

Abstract

To provide an operation device of an excavator, and an excavator which control the rotary drive of a rotary drive device, and can reduce operation loads on an operation lever.SOLUTION: An operation device for imparting a lever operation signal to a rotary drive control valve 37 of a rotary drive device on the basis of tilting of an operation lever 33 includes a controller 35, an operation detection part 36 for detecting the tilting of the operation lever, and a rotation holding switch 34 arranged in an operator cab independently from the operation lever, wherein the controller interrupts a lever operation signal and imparts an alternative operation signal corresponding to the lever operation signal to the rotary drive control valve when detection signals are simultaneously input from the operation detection part and the rotation holding switch, interrupts the alternative operation signal on the basis of the tilting through a neutral position of the operation lever in a state where the alternative operation signal is imparted, and recovers only the lever operation signal from the interruption state on the basis of the tilting through the neutral position of the operation lever in a state where the lever operation signal and the alternative operation signal are interrupted.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an operating device for an excavating machine and an excavating machine, and more particularly to an operating device for an excavating machine provided with a rotary drive device that rotationally drives an excavating tool, and an excavating machine. [Background technology]

[0002] Generally, construction machinery equipped with various working devices such as cargo handling equipment and excavation equipment performs desired operations by tilting a control lever located in the driver's seat. These control levers are equipped with a fail-safe function, and when the operator's hand is released from a predetermined operating position, the elastic force of a built-in spring returns the control lever to a neutral position, stopping the operation of the machine. Meanwhile, in order to meet the demand for maintaining a constant operating position of the control lever from the standpoint of convenience, a holding / release device has been proposed that can hydraulically hold the tilted position of the control lever (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-124010 Summary of the Invention [Problem to be solved by the invention]

[0004] Among various types of construction machinery, excavation machines that work underground, for example, use the Kelly drive for continuous rotational drive for long periods of time when removing obstacles, so the burden of operating the control lever can be reduced if the rotational drive can be held in a held state. However, since the held state is not a fail-safe state, from a safety standpoint it is necessary that the held state not be entered easily, and that the rotational drive quickly stops when the return operation is performed.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an operating device for an excavating machine and an excavating machine that are capable of controlling the rotational drive of a rotary drive device to reduce the operating burden on an operating lever. [Means for solving the problem]

[0006] In order to achieve the above object, the operating device for an excavating machine of the present invention is equipped to an excavating machine which includes a lower traveling body, an upper rotating body rotatably provided on the upper part of the lower traveling body, a cab mounted on the upper rotating body and defining an operator's cab therein, a leader provided upright at the front of the upper rotating body, and a rotary drive unit which can rise and fall along the leader, and which applies a lever operation signal to a rotary drive control valve of the rotary drive unit based on the tilting of an operating lever arranged in the operator's cab, the operating device comprising: a controller; an operation detection unit which detects the tilting of the operating lever; and a rotation holding switch which is arranged in the operator's cab independently of the operating lever, The bar is provided with an elastic member that returns the lever shaft from the tilted position to the neutral position, and when detection signals from the operation detection unit and the rotation hold switch are input simultaneously, the controller blocks the lever operation signal and applies an alternative operation signal corresponding to the lever operation signal to the rotation drive control valve, and when the alternative operation signal is applied, blocks the alternative operation signal based on tilting of the operating lever past the neutral position, and when both the lever operation signal and the alternative operation signal are blocked, returns only the lever operation signal from the blocked state based on tilting of the operating lever past the neutral position.

[0007] The lever operation signal is a lever operation pressure signal of the hydraulic oil flowing through a pilot oil passage, and the pilot oil passage is provided with a remote control valve that changes the lever operation pressure signal in accordance with the tilt of the operating lever, and an electromagnetic control valve provided downstream of the remote control valve, and the operation detection unit is a pressure transmitter that detects the lever operation pressure signal in the pilot oil passage between the remote control valve and the electromagnetic control valve, and the electromagnetic control valve is made up of an oil passage shutoff valve that shuts off the flow of hydraulic oil from the remote control valve, and an oil passage switching valve that switches the oil passage by connecting the pilot oil passage downstream of the oil passage shutoff valve to an attached supply pilot oil passage, and the controller controls the pressure transmitter and the rotation holding valve. When detection signals from the holding switches are input at the same time, the oil passage shutoff valve is controlled to shut off the flow of hydraulic oil, and the oil passage switching valve is controlled to introduce the hydraulic oil flowing through the supply pilot oil passage into the downstream pilot oil passage, thereby applying an alternative operating pressure signal corresponding to the lever operating pressure signal to the rotary drive control valve, and when the alternative operating pressure signal is applied, the oil passage switching valve is controlled to shut off the alternative operating pressure signal based on the tilting of the operating lever through the neutral position, and when the lever operating pressure signal and the alternative operating pressure signal are shut off, only the lever operating pressure signal is restored from the shut-off state based on the tilting of the operating lever through the neutral position.

[0008] Furthermore, the inside of the operator's cab is divided into two spaces in the left-right width direction by a vertical plane passing through the center of the operator's seat, the operation lever is arranged in one space of the divided interior spaces and the rotation hold switch is arranged in the other space, and the shortest distance between the operation lever and the rotation hold switch is greater than the left-right width dimension of the operator's seat. [Effects of the Invention]

[0009] According to the present invention, the operating device provided on the excavating machine is provided with a rotation hold switch that is arranged independently of the operating lever, and when detection signals from the operation detection unit and the rotation hold switch are simultaneously input to the controller, the lever operation signal is blocked and an alternative operation signal corresponding to the lever operation signal is applied to the rotary drive control valve.Therefore, even when the operating lever is returned to the neutral position, it is possible to maintain the rotational state of the rotary drive device based on the alternative operation signal, thereby reducing the operating burden on the operating lever.

[0010] Furthermore, by placing importance on the independence of the rotation hold switches, simultaneous operation input from two locations can prevent unintentional transition to the rotation hold state due to misoperation, etc. On the other hand, after transition to the rotation hold state reflecting the operator's operating intention, the operation lever is left to elastically return to neutral, eliminating the involvement of lever operation for rotation drive, and making it possible to position the operation lever appropriately in the driving posture, allowing for stable driving operations that are not dependent on the operator's level of skill.

[0011] Furthermore, since the alternative operation signal is cut off based on tilting the operating lever past the neutral position when the alternative operation signal is applied, the stop operation from the rotation-holding state can be easily and quickly performed with a single main operation input, which is also excellent in terms of safety.In addition, since only the lever operation signal is returned from the cut-off state based on tilting the operating lever past the neutral position when both the lever operation signal and the alternative operation signal are cut off, even if the operating lever is tilted at the time of the stop operation, it is possible to smoothly return to the initial state while ensuring safety. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a side view of a driver's cab equipped with an operating device according to an embodiment of the present invention; [Figure 2] FIG. [Figure 3] FIG. 10 is a diagram showing the arrangement of a rotation holding switch. [Figure 4] FIG. [Figure 5] FIG. 10 is a control circuit diagram showing a state in which the rotation control lever is tilted. [Figure 6] FIG. 10 is a control circuit diagram showing a state in which detection signals from the operation detection unit and the rotation holding switch are simultaneously input to the controller. [Figure 7] FIG. 10 is a control circuit diagram showing a state in which the rotation operation lever is returned to the neutral position in a rotation holding state in which an alternative operation signal is applied to the rotation drive control valve. [Figure 8] FIG. 10 is a control circuit diagram showing a state in which the rotary operation lever is tilted from the neutral position and the alternative operation signal is cut off. [Figure 9] FIG. 10 is a control circuit diagram showing a state in which the rotary operation lever is returned to the neutral position with the alternative operation signal being cut off. [Figure 10] 1 is a side view of an excavator to which an operating device according to an embodiment of the present invention is applied; DETAILED DESCRIPTION OF THE INVENTION

[0013] 1 to 10 show an example of an operating device according to the present invention applied to an excavating machine. As shown in FIG. 10, the excavating machine 11 is a multipurpose excavating machine capable of various construction tasks, such as casing excavation and ground improvement work. It includes a base machine 14 consisting of a crawler-equipped lower track body 12 and an upper rotating body 13 rotatably mounted on the lower track body 12, a leader 15 erected at the front of the upper rotating body 13, and a hoisting cylinder 16 supporting the leader 15 from the rear. A leader support 17 for supporting the leader 15 so that it can be raised or lowered is provided at the front of the upper rotating body 13, and a piping support member 18 for supporting piping is provided above the front of the upper rotating body 13. An operator's cab 19 is provided on the right side of the upper rotating body 13, and a power unit 20 equipped with an engine and a hydraulic pump serving as a hydraulic source is provided on the left side.

[0014] The leader 15 is made up of multiple leader members connected together, each having a rectangular cylindrical cross section, and is rotatably attached to a support shaft in the vehicle width direction provided on the leader support 17. A top sheave 23 around which the kelly rope 22 of the kelly bar 21 and the like are wound is attached to the upper end of the leader 15, and a kelly drive 24, which is an example of a rotation drive device that rotates the kelly bar 21, and a guide device 25 for the kelly bar 21 are attached to the front surface of the leader 15. A rack gear 26, which is a component of the rack and pinion lifting device, is attached to the center of the front surface of the leader 15, and a pair of left and right guide pipes 27, 27 are attached continuously over the entire length of the leader 15 at the front ends of both sides, and serve as mounting parts for the kelly drive 24 and guide device 25.

[0015] The kelly drive 24 is configured around a device main body 24a that has a rotatable kelly bar 21, and has a pair of left and right guide gibs 24b, 24b that protrude rearward and slide against guide pipes 27, 27 of the leader 15. The kelly drive 24 moves up and down along the front of the leader 15 by rotating a pair of left and right pinions that mesh with the rack gear 26 using an elevator hydraulic motor (not shown).

[0016] The Kelly drive 24 also includes a rotary drive hydraulic motor 24c connected to a reduction gear mechanism within the device body 24a, and an electromagnetic proportional pressure reducing valve (not shown) attached to the rotary drive hydraulic motor 24c. The rotary drive hydraulic motor 24c is a swash plate-type variable displacement hydraulic motor whose capacity can be changed by changing the tilt angle of the swash plate. The tilt angle of the swash plate, i.e., the displacement (amount of fluid discharged per rotation of the motor), is adjusted by a regulator. As a result, for a constant flow rate, the rotary drive hydraulic motor 24c will rotate faster as the displacement volume decreases, and the rotation speed will decrease as the displacement volume increases, but since more hydraulic oil is used to rotate, it will generate greater torque.

[0017] The kelly bar 21 employs a well-known locking kelly bar equipped with a locking means capable of transmitting a strong pushing force in hard ground, and has a structure (for example, a four-stage structure) combining multiple kelly bar members, which is configured to expand and contract according to the excavation depth. The locking means consists of a pair of plates attached to adjacent kelly bar members, which fit together and lock together to efficiently transmit the pushing force to the excavation tool attached to the tip (lower end) of the kelly bar 21.

[0018] When the excavating machine 11 is used for the purpose of casing excavation, a casing (not shown) is used as the excavation tool. The casing is connected to the tip of the kelly bar 21 via a coupling. As a result, the cylindrical body of the casing is arranged concentrically with the rotation axis of the kelly drive 24 and rotates integrally with it, and by lowering the kelly drive 24 while driving the kelly bar 21 to rotate, the excavation bit at the tip of the casing excavates the ground or cuts away obstacles such as old foundations.

[0019] To perform such casing drilling, an operator's compartment is defined within the cab 19, and devices such as operating levers and pedals for driving, turning, raising and lowering the Kelly drive 24, and rotating drive, as well as push button switches and touch panel displays are concentrated near the operator's seat for ease of use.In addition, an operating device including a controller electrically connected to these operating devices is installed.

[0020] 1 to 3 show various operating units arranged in the driver's cab. To facilitate understanding of the explanation, each figure is shown in a reversed front-to-back orientation relative to the external view in Fig. 10, with the right side in Fig. 1 representing the front, the left side representing the rear, the far side of the page representing the left side, and the near side representing the right side. When the driver's cab is divided into two in the width direction (the vertical direction in Fig. 2) by a vertical plane S passing through the center of driver's seat 28, the various operating units are arranged side-by-side across driver's seat 28, with left-hand operation input unit 29 operated with the left hand in the left space and right-hand operation input unit 30 operated with the right hand in the right space.

[0021] In the window frame corresponding to the driver's seat 28 in the left-hand space, there are usually disposed a ceiling position operation input unit 31 and a support position operation input unit 32, which are operated with the left hand. These operation input units 31, 32 consist of a group of switches aligned in a horizontal or vertical row along the wall surface, and although they are operated less frequently than main operations such as lever operations that cause the machine to operate, they can be easily operated even while seated.

[0022] Furthermore, as will be described in detail later, the shortest distance between the Kelly drive lift / rotation operation lever (two-axis operation lever) 33 belonging to the right-hand operation input unit 30 and the rotation hold switch 34 belonging to the support column position operation input unit 32 is greater than the left-right width of the driver's seat 28. In other words, as can be seen from Figure 2, the operation lever 33 and the rotation hold switch 34 arranged independently thereof are spaced apart from each other in an area outside the area of ​​the driver's seat 28, which has a left-right width W, inside the driver's cab, and although both hands are required to operate them simultaneously, they can be handled in a natural posture.

[0023] Incidentally, since the excavating machine 11 performs rotational drive of the kelly drive 24 continuously for a long period of time when, for example, performing casing drilling, being able to hold the rotational drive reduces the operating burden of the operating lever 33. Therefore, the operating device allows the operator to select to hold the rotational drive of the kelly drive 24.

[0024] The following describes the case where rotation hold operation is performed, with reference to Figures 4 to 9. Figure 4 shows the control circuit of the rotation operation system, which mainly comprises a controller 35 that executes a control program, an operation detection unit 36 ​​that detects the tilt of the operating lever 33, and a rotation hold switch 34, and in the state before the system is switched to the rotation hold mode (lever mode), it is configured to give a lever operation signal to the rotation drive control valve (rotation direction switching valve) 37 of the Kelly drive 24 based on the tilt of the operating lever 33.

[0025] The lever operation signal is a pressure signal of hydraulic oil that selectively flows through pilot oil passages 38, 39 on the forward and reverse sides of the rotation drive. The pilot oil passages 38, 39 are equipped with a remote control valve 40 that changes the lever operation pressure signal (pilot secondary pressure) in accordance with the tilt of the operating lever 33, and an electromagnetic control valve 41 provided downstream of the remote control valve 40.

[0026] The operating lever 33 is configured using a two-axis remote control valve 40, with left and right tilting being assigned to the rotation of the Kelly drive 24 and front and rear tilting (not shown) to the elevation of the Kelly drive 24. Furthermore, by adjusting the tilting direction of the operating lever 33, combined rotation and elevation can be performed, i.e., casing can be pushed in and pulled out with one hand using a single lever during casing drilling. Furthermore, the operating lever 33 incorporates a coil spring 33b as an elastic member that returns the lever shaft 33a from the tilted position to the neutral position.

[0027] The rotation holding switch 34 is an automatic return type push button switch that is turned on (pushed down), and a button operation signal is input to the controller 35 when the switch is turned on.

[0028] The operation detection unit 36 ​​is made up of a forward pressure transmitter 36a and a reverse pressure transmitter 36b that detect a lever operation pressure signal in detection pilot oil passages 38a and 39a between the remote control valve 40 and the solenoid control valve 41. The lever operation pressure signal generated based on the tilt of the operating lever 33 is converted into an electric signal by the pressure transmitters 36a and 36b and input to the controller 35.

[0029] The electromagnetic control valve 41 is operated by a control command from the controller 35, and comprises forward and reverse side oil passage shut-off valves (lever operation disabling solenoid valves) 42, 43 that shut off the flow of hydraulic oil from the remote control valve 40, and forward and reverse side oil passage switching valves (rotation holding solenoid valves) 45, 46 that selectively connect the common pilot oil passages 38b, 39b downstream of the oil passage shut-off valves 42, 43 to the branch oil passages 44a, 44b of the attached supply pilot oil passage 44, thereby switching the intermediate pilot oil passages 38c, 39c between the oil passage shut-off valves 42, 43 to the supply pilot oil passage 44.

[0030] The hydraulic oil flowing through the supply pilot oil passage 44 has the same hydraulic pressure source as the hydraulic oil flowing through the remote control valve 40. That is, although not shown, the supply pilot oil passage 44 is a branch oil passage obtained by branching off the P line of the pilot pump.

[0031] When the control circuit configured in this way is operated to perform rotation holding operation, first the excavator 11 is moved to the construction site, and after going through the necessary setup, the rotation and lowering operation of the Kelly drive 24 is carried out. Focusing on the rotation operation, as shown in Figure 5, tilting the operating lever 33 to the forward rotation side gives a lever operation pressure signal to the rotation drive control valve 37, and excavation proceeds while obtaining pressurized oil from the main pump (not shown) and rotating the Kelly drive 24 in the forward direction.

[0032] When this lever mode is executed, the controller 35 detects the tilt state of the operating lever 33 using a signal from the forward rotation pressure transmitter 36a, but does not issue a control command to the electromagnetic control valve 41. As a result, both the oil passage shutoff valve 42 and the oil passage switching valve 45 are maintained in a state in which the forward rotation side pilot oil passage 38 is communicated (de-energized state), and therefore the flow of hydraulic oil from the supply pilot oil passage 44 is blocked by the oil passage switching valves 45, 46 in the closed state.

[0033] When the operator simultaneously operates the operating lever 33 and the rotation hold switch 34 based on his / her intention to switch to rotation hold operation, as shown in Fig. 6, the controller 35 simultaneously receives "ON" detection signals from the forward rotation pressure transmitter 36a and the rotation hold switch 34. The controller 35 then switches the forward rotation oil passage shutoff valve 42 to shut off the flow of hydraulic oil in the detection pilot oil passage 38a, and switches the forward rotation oil passage switching valve 45 to introduce hydraulic oil flowing in the supply pilot oil passage 44 (branch oil passage 44a) into the common pilot oil passage 38b, thereby applying an alternative operating pressure signal corresponding to the lever operating pressure signal to the rotation drive control valve 37. At this time, the intermediate pilot oil passage 38c is connected to the T-line that returns hydraulic oil to the tank in accordance with the switching control of the forward rotation oil passage shutoff valve 42 and the forward rotation oil passage switching valve 45.

[0034] When the rotation hold mode is executed, an alternative operating pressure signal is given as a control command to the rotation drive control valve 37, and the rotation drive of the Kelly drive 24 continues. Here, as shown in Figure 7, if the tension on the lever operation (left and right direction) is released and the operating lever 33 is returned to the neutral position, the flow of hydraulic oil to the detection pilot oil passage 38a is blocked by the closed remote control valve 40. However, because the alternative operating pressure signal is given to the rotation drive control valve 37, the rotation state of the Kelly drive 24 is maintained even when the operating lever 33 is returned to the neutral position. Also, in this state, the controller 35 receives "off" detection signals from both the forward rotation pressure transmitter 36a and the rotation hold switch 34.

[0035] While the rotation hold mode is in operation, the operator can concentrate on the operation of lowering the kelly drive 24. However, there are cases where it is desired to exit the rotation hold mode due to the behavior of the machine, etc. In such cases, the operating lever 33 is tilted from the neutral position toward either the forward rotation side or the reverse rotation side. For example, as shown in FIG. 8, when the operating lever 33 is tilted toward the forward rotation side again (for example, by 3 degrees or more), a lever operating pressure signal generated based on this is input to the controller 35 via the forward rotation pressure transmitter 36a.

[0036] At this time, the controller 35, to which the lever operation detection signal "ON" has been input, switches and controls the forward rotation oil passage switching valve 45 based on the tilt of the operating lever 33 past the neutral position (Fig. 7) while the alternative operating pressure signal is being applied (Fig. 6), to block the alternative operating pressure signal (Fig. 8). As a result, no control command is sent to the rotation drive control valve 37, and the rotation (hydraulic drive) of the kelly drive 24 is quickly stopped.

[0037] When the operating lever 33 is in a tilted state (FIG. 8), the flow of hydraulic oil from the remote control valve 40 in the forward rotation pilot oil passage 38 is blocked by the closed forward rotation oil passage shutoff valve 42, so rotation of the Kelly drive 24 is maintained stopped even when the operating lever 33 is in a tilted position. Then, when the operating lever 33 is returned to the neutral position almost simultaneously with or immediately after rotation of the Kelly drive 24 stops, the flow of hydraulic oil to the detection pilot oil passage 38a is blocked by the closed remote control valve 40, as shown in FIG.

[0038] Here, the controller 35 receives an "off" lever operation detection signal from the forward rotation pressure transmitter 36a and switches the forward rotation oil passage shutoff valve 42 to maintain the forward rotation pilot oil passage 38 in a connected state. In this way, the system leaves the rotation hold mode and transitions (returns) to the lever mode, which is the initial state. At this time, with the lever operation pressure signal and the alternative operation pressure signal in a cut-off state (FIG. 8), the controller 35 returns only the lever operation pressure signal from the cut-off state (FIG. 8) based on the tilt of the operation lever 33 through the neutral position (FIG. 9), as shown in FIG. 5. This allows the operator to proceed with casing drilling by operating the lever as desired.

[0039] As described above, according to the present invention, the operating device provided on the excavating machine 11 is provided with the rotation hold switch 34 arranged independently of the operating lever 33, and when detection signals from the operation detection unit 36 ​​and the rotation hold switch 34 are simultaneously input to the controller 35, the lever operation signal is cut off and an alternative operation signal corresponding to the lever operation signal is given to the rotation drive control valve 37. Therefore, even when the operating lever 33 is returned to the neutral position, it is possible to maintain the rotation state of the rotation drive device 24 based on the alternative operation signal, thereby reducing the operating burden of the operating lever 33.

[0040] Furthermore, by placing importance on the independence of the rotation hold switch 34, it is possible to prevent unintentional transition to the rotation hold state due to erroneous operation or the like by simultaneous operation input from two locations. On the other hand, after transition to the rotation hold state reflecting the operator's operational intention, it is possible to eliminate the involvement of lever operation for rotation drive by simply leaving it to the elastic return of the control lever 33 to neutral, and it is possible to position the control lever 33 appropriately in the driving posture, allowing for stable driving operation that is not dependent on the operator's level of skill.

[0041] Furthermore, since the alternative operation signal is cut off based on tilting of the operating lever 33 past the neutral position when the alternative operation signal is applied, the stop operation from the rotation holding state can be easily and quickly performed by inputting the main operation from one location, which is also excellent in terms of safety. In addition, since only the lever operation signal is returned from the cut-off state based on tilting of the operating lever 33 past the neutral position when both the lever operation signal and the alternative operation signal are cut off, even if the operating lever is tilted at the time of the stop operation, it is possible to smoothly return to the initial state while ensuring safety.

[0042] In addition, since the lever operation signal is the lever operation pressure signal (pilot secondary pressure) of the hydraulic oil flowing through the pilot oil passage, it can be easily incorporated into existing hydraulic pilot operation type operating devices as a new or retrofit, resulting in an operating device that is inexpensive, simple to control, and highly robust.

[0043] Furthermore, the interior space is divided into two in the left-right width direction by a vertical plane S that passes through the center of the driver's seat 28. The control lever 33 is located in one space, and the rotation hold switch 34 is located in the other space, and the shortest distance between the control lever 33 and the rotation hold switch 34 is greater than the left-right width dimension W of the driver's seat 28, so the rotation hold state is not easily entered. In other words, rotation hold operation that is against the operator's will can be restricted.

[0044] Furthermore, the operating lever 33 is configured for two-axis operation, with left and right tilting assigned to rotating the Kelly drive 24 and front and rear tilting assigned to raising and lowering the Kelly drive 24, allowing for efficient operation input for the construction of the excavation machine 11.Even when performing combined operations by adjusting the tilt direction of the operating lever 33, casing can be pushed in and pulled out by operating one lever with one hand, and it can also be easily coordinated with rotation holding operation.

[0045] The present invention is not limited to the above-described embodiment, and the configuration and arrangement of the operating device can be changed as appropriate depending on the specifications of the driver's cab. Furthermore, although a hydraulic pilot-operated operating lever is used in the embodiment, an electrically operated operating lever may also be used. In this case, the rotary drive control valve is electrically controlled by a controller, and a lever operation signal from a potentiometer serving as an operation detection unit can be directly input to the controller. Furthermore, the number of axes of the operating lever can also be arbitrary. Additionally, while casing excavation (obstacle removal work) has been described as an example, the present invention is not limited to this, and can be applied to other construction methods such as ground improvement. [Explanation of symbols]

[0046] 11...Excavation machine, 12...Lower running body, 13...Upper rotating body, 14...Base machine, 15...Leader, 16...Drilling cylinder, 17...Leader support, 18...Pipe support member, 19...Operator's cab, 20...Power unit, 21...Kelly bar, 22...Kelly rope, 23...Top sheave, 24...Kelly drive, 24a...Device body, 24b...Guide gib, 24c...Hydraulic motor for rotational drive, 25...Guide device, 26...Rack gear, 27...Guide pipe, 28...Operator's seat, 29...Left-hand side operation input unit, 30...Right-hand side operation input unit, 31...Ceiling position operation input unit, 32...Support position operation input unit, 33...Operation lever, 33a...Lever shaft, 33b...Coil spring, 3 4...Rotation holding switch, 35...Controller, 36...Operation detection unit, 36a...Forward rotation pressure transmitter, 36b...Reverse rotation pressure transmitter, 37...Rotation drive control valve, 38...Forward rotation side pilot oil passage, 38a...Detection pilot oil passage, 38b...Common pilot oil passage, 38c...Intermediate pilot oil passage, 39...Reverse rotation side pilot oil passage, 39a...Detection pilot oil passage, 39b...Common pilot oil passage, 39c...Intermediate pilot oil passage, 40...Remote control valve, 41...Solenoid control valve, 42...Forward rotation side oil passage shutoff valve, 43...Reverse rotation side oil passage shutoff valve, 44...Supplementary pilot oil passage, 44a, 44b...Branch oil passage, 45...Forward rotation side oil passage switching valve, 46...Reverse rotation side oil passage switching valve

Claims

1. The excavator is equipped with a lower traveling body, an upper rotating body rotatably provided on the upper part of the lower traveling body, a cab mounted on the upper rotating body and defining an operator's cabin therein, a leader erected at the front of the upper rotating body, and a rotary drive device that can rise and fall along the leader, an operating device that applies a lever operation signal to a rotary drive control valve of the rotary drive device based on tilting of an operating lever arranged in the driver's cab, A controller; an operation detection unit that detects tilting of the operation lever; a rotation holding switch disposed in the driver's cab independently of the operation lever, The operating lever is provided with an elastic member that returns the lever shaft from the tilted position to the neutral position, when detection signals are simultaneously input from the operation detection unit and the rotation hold switch, the controller blocks the lever operation signal and applies an alternative operation signal corresponding to the lever operation signal to the rotation drive control valve; In a state where the alternative operation signal is applied, the alternative operation signal is cut off based on the tilting of the operating lever past the neutral position, An operating device characterized in that, when the lever operation signal and the alternative operation signal are in a cut-off state, only the lever operation signal is restored from the cut-off state based on tilting of the operating lever past a neutral position.

2. the lever operation signal is a lever operation pressure signal of hydraulic oil flowing through a pilot oil passage, the pilot oil passage includes a remote control valve that changes the lever operation pressure signal in accordance with tilting of the operating lever, and an electromagnetic control valve provided downstream of the remote control valve, the operation detection unit is a pressure transmitter that detects the lever operation pressure signal in the pilot oil passage between the remote control valve and the electromagnetic control valve, The electromagnetic control valve comprises an oil passage shutoff valve that shuts off the flow of hydraulic oil from the remote control valve, and an oil passage switching valve that switches the oil passage by connecting a pilot oil passage downstream of the oil passage shutoff valve to an attached supply pilot oil passage, when detection signals from the pressure transmitter and the rotation hold switch are simultaneously input, the controller controls the oil passage shutoff valve to shut off the flow of hydraulic oil, and controls the oil passage switching valve to introduce the hydraulic oil flowing through the supply pilot oil passage into the downstream pilot oil passage, thereby applying an alternative operating pressure signal corresponding to the lever operating pressure signal to the rotation drive control valve; In a state where the alternative operating pressure signal is applied, the oil passage switching valve is controlled based on tilting of the operating lever past the neutral position to cut off the alternative operating pressure signal, 2. The operating device according to claim 1, wherein, when the lever operating pressure signal and the alternative operating pressure signal are in a cut-off state, only the lever operating pressure signal is restored from the cut-off state based on tilting of the operating lever past the neutral position.

3. The interior of the driver's cab is divided into two spaces in the left-right width direction by a vertical plane passing through the center of the driver's seat, and the operation lever is disposed in one space of the divided interior spaces, and the rotation holding switch is disposed in the other space, 3. The operating device according to claim 1, wherein the shortest distance between the operating lever and the rotation holding switch is greater than the left-right width of the driver's seat.

4. An excavating machine comprising the operating device according to claim 1 or 2.

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