Work equipment

Abstract

To provide a work machine that allows the posture of a movable part to be grasped without increasing a burden of calculation processing.SOLUTION: A first boom 411 is provided so as to turn on a mast frame 21, and a second boom 413 is provided so as to turn relatively with respect to the first boom 411 in a direction intersecting with a turning direction of the first boom 411. The second boom 413 can turn to a first turning position which is a relative backing position with respect to the first boom 411, a second turning position which is a relative intermediate position with respect to the first boom 411, and a third turning position which is a relative advancing position with respect to the first boom 411 according to turning angles of the second boom. In response to an instruction for the second boom 413 to start turning from the second turning position and the third turning position toward the first turning position, a control unit t determines an abnormal state and stops the operation of the second boom 413 if it is determined that there is no change in a detection signal of a first switch Sw1 within the set lapse time after the start of the turning of the second boom 413.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to a working machine.

Background Art

[0002] A mowing device has been proposed in Patent Document 1, in which a plurality of arms are connected and a mowing tool for ground work is attached to the arms. This mowing device includes sensors for detecting the position and posture of the arms and the mowing tool, and controls the mowing operation by the mowing tool by subjecting the information detected by the sensors to arithmetic processing in a control unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, if the information on the position and posture, which is the information obtained from the sensors, is input to the control unit as a direct or linear one, the burden on the arithmetic processing increases. Also, as the control of the movable parts and directions of the arms increases, the burden on the arithmetic processing inevitably increases. When trying to perform arithmetic processing on a large amount of information, the processing ability has to be increased, so there is a problem that the configuration of the control unit for performing the arithmetic processing becomes expensive. Further, when an abnormality occurs in the sensors and an accurate signal cannot be received from the sensors, the operation control of the arms cannot be properly performed, and it is also conceivable that the arms perform unintended operations. An object of the present invention is to provide a working machine capable of preventing unintended operations while reducing the arithmetic burden related to the attitude control of the movable parts.

Means for Solving the Problems

[0005] This invention is A first boom that is rotatable, The system includes a second boom that is rotatable relative to the first boom in a direction intersecting the rotation direction of the first boom, and which is positioned to be in a first rotation position which is a retracted position relative to the first boom, a second rotation position which is an intermediate position, and a third rotation position which is an advanced position, depending on the rotation angle. A first switch for detecting the second slewing position, which is the intermediate position of the second boom, A second switch for detecting the third slewing position, which is the forward position of the second boom, The system includes a control unit connected to the first switch and the second switch, which can recognize the first slewing position (the retracted position), the second slewing position (the intermediate position), and the third slewing position (the forward position) of the second boom by receiving detection signals from the first switch and the second switch, The control unit, upon receiving an instruction for the second boom to begin rotating from the second rotation position (intermediate position) and the third rotation position (advancing position) toward the first rotation position (retracted position), determines that there is no change in the detection signal of the first switch within a set elapsed time after the second boom begins rotating, and determines that an abnormal condition exists, and stops the operation of the second boom. A work machine characterized by, It relates to.

[0006] This invention is In addition to the first boom and the second boom, it has several more movable parts, When the control unit determines that the abnormal condition is present, it stops the operation of all of the multiple movable parts. A work machine characterized by, It relates to.

[0007] This invention further, In addition to the first boom and the second boom, it has several more movable parts, The control unit That is correct If it is determined that the state is normal, the operation of the multiple movable parts is permitted to continue. A work machine characterized by, It relates to. [Effects of the Invention]

[0008] The present invention can provide a work machine that can prevent unintended movements while reducing the computational burden related to the posture control of movable parts. [Brief explanation of the drawing]

[0009] [Figure 1] This is a front view of a work machine according to an embodiment of the present invention, in its stowed state, as seen from the rear in the direction of travel. The second boom is in the first slewing position, which is the retracted position. [Figure 2] This is a front view of the working machine according to an embodiment of the present invention when it is deployed. [Figure 3] This is a side view of a work machine according to an embodiment of the present invention, showing an example of a working position. The solid line indicates the working section and other parts in the third slewing position, where the second boom is in the forward position. The dashed line section 51-1 shows the working section and other parts in the first slewing position, where the second boom is in the retracted position, and 51-2 shows the working section and other parts in the second slewing position, where the second boom is in the intermediate position. [Figure 4] This is an enlarged view of the vicinity of the third pivot axis of a work machine according to an embodiment of the present invention, as seen from the axial direction of the third pivot axis, where the second boom is in the first pivot position, which is the retracted position. [Figure 5] This is an enlarged view of the vicinity of the third pivot axis of a work machine according to an embodiment of the present invention, as seen from the axial direction of the third pivot axis, where the second boom is in the intermediate position, the second pivot position. [Figure 6] This is an enlarged view of the vicinity of the third pivot axis of a work machine according to an embodiment of the present invention, as seen from the axial direction of the third pivot axis, where the second boom is in the forward position, which is the third pivot position. [Figure 7] This is an enlarged view of a work machine according to an embodiment of this invention. It is an enlarged view of the third slewing axis as seen from the side, showing the third slewing position where the second boom is in the forward position. Both the first switch and the second switch are operated. [Figure 8] This is a hydraulic circuit diagram according to an embodiment of the present invention. [Figure 9]This is a perspective view of an operation unit of a working machine according to an embodiment of the present invention. [Figure 10] This is a block diagram showing the configuration of a working machine according to an embodiment of the present invention. [Figure 11] This is a flowchart showing a case where a turning instruction is received from the second turning position side, which is the third turning position or the intermediate position where the second boom of the working machine according to the embodiment of the present invention is in the forward position, toward the first turning position, which is the backward position. [Figure 12] This is a flowchart showing a case where a turning instruction for the first boom to move toward the storage position side is received while the second boom of the working machine according to the embodiment of the present invention is in the first turning position, which is the backward position. [Figure 13] This is a flowchart showing a case where a turning instruction for the first boom to move toward the storage position side is received while the second boom of the working machine according to the embodiment of the present invention is in the first turning position, which is the backward position.

Mode for Carrying Out the Invention

[0010] The mechanical structure of an embodiment of a working machine according to the present invention will be described based on the drawings. A is a working machine. In an embodiment of the present invention, the working machine A is related to a working machine that performs operations such as mowing grass. The working machine A is attached and driven to a traveling body composed of a tractor or the like. The traveling body composed of a tractor or the like attaches the working machine A to the rear, and in FIG. 1, it is located on the back side of the working machine A. Although not shown, an operator who operates the traveling body and the working machine A rides on the traveling body.

[0011] 11 is a main frame. The main frame 11 is attached to the working machine A. The main frame 11 is mounted on the rear side in the traveling direction of the traveling body. As shown in the figure, the main frame 11 is provided with mounting portions 111 and 112 for mounting to the traveling body. The two 111 are lower mounting portions (lower), and 112 is an upper mounting portion (top), and the working machine A is mounted to the traveling body at three points.

[0012] In Figure 3, 22 is the input shaft. The input shaft 22 takes driving force from the attached traveling machine to the work implement A. In the gear shifting unit (not shown), the driving force input from the mobile body is shifted via the input shaft 22.

[0013] In Figures 1 to 3, 24 is a hydraulic pump, which is a fluid pressure source. The hydraulic pump 24 is driven by a driving force that is input from the traveling machine body via an input shaft 22 and shifted by a transmission (not shown). The hydraulic pump 24 delivers hydraulic pressure to the hydraulic equipment of the work machine A, which is operated by hydraulic pressure. The part 25 shown in Figures 1 and 2 is a valve unit, which is a directional control valve. The valve unit 25 controls the flow of hydraulic pressure by switching it.

[0014] In Figures 1 to 3, 21 is the mast frame. 211 is the mast frame pivot shaft. The mast frame 21 is rotatably attached to the main frame 11 by the mast frame pivot shaft 211. The mast frame 21 is provided on one end or the center of the main frame 11 of the work machine A in the direction of travel. In this embodiment, the mast frame pivot axis 211 is provided at a position slightly offset to the left in the direction of travel from the center, which is one end of the main frame 11, and the mast frame 21 is positioned on the left side in the direction of travel, which is one end of the main frame 11.

[0015] The mast frame 21 is capable of rotatably extending the extension mechanism 41, which will be described later, in the horizontal direction. The mast frame 21 is capable of rotatably extending the extension mechanism 41 around the mast frame pivot axis 211, which is the vertical axis. By rotating the extension mechanism 41 horizontally around the mast frame pivot axis 211, the mast frame 21 can change its posture between a normal position in which the extension mechanism 41 is positioned to the left and right sides in the direction of travel, and a retracted position in which the extension mechanism 41 is positioned to the rear in the direction of travel. The mast frame 21 can be fixed to the main frame 11 in a manner that prevents it from swiveling. In Figure 1, the mast frame 21 is shown in a state where the other end of the first boom 411 of the telescopic means 41 is fixed in a position that allows it to swivel to the left and right sides relative to the direction of travel of the traveling machine.

[0016] 31 is a tank. In this embodiment, tank 31 is an oil tank. Tank 31 is installed at the other end of the main frame 11 on the left and right sides in the direction of travel of the work machine A. Since each cylinder used in the work machine A is a hydraulic cylinder, tank 31 stores the oil for driving each oil cylinder.

[0017] 41 is an extension / retraction mechanism. One end of the extension / retraction mechanism 41 is connected to a mast frame 21 that is rotatable near the main frame 11. As shown in Figure 1, the extension / retraction mechanism 41 can be folded into the work section 51 to position the work section 51 on the main frame 11 in a stored state, and as shown in Figure 2, the extension / retraction mechanism 41 can be extended to position the work section 51 laterally relative to the direction of travel from the main frame 11 in a working state.

[0018] In other words, the telescopic means 41 can be changed between a stored state where it is folded near the main frame 11, an extended state where it is extended to the side of the main frame 11, and an intermediate state. In this explanation, the stored state may be referred to as the storage state, and the extended state as the deployed state or working state. The telescopic mechanism 41 includes a first boom 411, a first connecting body 412, a second boom 413, a second connecting body 414, a first cylinder 415, a second cylinder 416, a third cylinder 417, and a fourth cylinder 418. These cylinders, including the first cylinder 415, the second cylinder 416, the third cylinder 417, and the fourth cylinder 418, are double-acting cylinders that rotate the boom.

[0019] The first boom 411 is connected to the mast frame 21 at one end and is rotatable in the vertical direction. The first boom 411 is swivelably mounted on the mast frame 21. The other end of the first boom 411 can be positioned far to the side in the direction of travel of the traveling machine. The first connecting body 412 is connected at one end to the tip of the other end of the first boom 411 and is provided to be rotatable in the vertical direction relative to the first boom 411. The second boom 413 is connected at one end to the tip of the other end of the first connecting body 412, and is provided so that it can rotate in the front-rear direction relative to the direction of travel when the mast frame 21 is in its normal position. In other words, the second boom 413 can rotate vertically in a direction parallel to the rotation direction of the first boom 411, and in the front-rear direction relative to the direction of travel, which is a direction intersecting the rotation direction of the first boom 411, by the first connecting body 412.

[0020] The second connecting body 414 has one end attached to the tip of the other end of the second boom 413, and when the mast frame 21 is in its normal position, it forms a parallel link with the first connecting body 412, thereby allowing it to move parallel to the first connecting body 412 in the front-rear direction without changing the inclination direction in the vertical and left-right directions relative to the front-rear direction of travel. In other words, even if the second boom 413 is rotated in the front-rear direction, the axial direction of the fourth pivot axis 418A of the second connecting body 414, which will be described later, is not changed. The first cylinder 415 is a hydraulic cylinder and connects the mast frame 21 and the first boom 411 via a link mechanism 42 consisting of two arms that connect the mast frame 21 and the first boom 411. The first cylinder 415 is for rotating the first boom 411 and is installed on the first boom 411. When it extends and retracts, it rotates together with the first boom 411, causing the first boom 411 to rotate up and down.

[0021] The first cylinder 415 rotates the first boom 411, which is the extension / retraction mechanism 41, around the first pivot axis 411A, which is a horizontal axis provided between the mast frame 21 and the first boom 411. The first boom 411 is connected to the mast frame 21 so as to be able to rotate vertically around the first pivot axis 411A as the pivot point. The first boom 411 is supported by a first pivot axis 411A, which is a horizontal axis, and is rotatable around the horizontal axis 411A. The first boom 411 can be changed between a stored state where it is folded over the top of the main frame 11 and an extended state where it is swung to the side of the main frame 11.

[0022] The second slewing shaft 413A is an axis that connects the first boom 411 to the first connecting body 412, which is a connecting body, and is installed parallel to the first slewing shaft 411A. The first connecting body 412 is provided with one end rotatable in the same direction as the rotation direction of the first boom 411 by a second slewing axis 413A which is parallel to the first slewing axis 411A. A third pivot axis 417A is provided at the other end of the first connecting body 412, which is a connecting body. By connecting one end of the second boom 413 to the third pivot axis 417A, the second boom 413 can pivot around the third pivot axis 417A. The third pivot axis 417A is provided in a direction that intersects with the first pivot axis 411A and the second pivot axis 413A. Therefore, the second boom 413 can pivot by the third pivot axis 417A in a direction that intersects with the first boom 411.

[0023] The second boom 413 can be rotated in a direction parallel to the first boom 411 via the second pivot axis 413A through the first connecting body 412. In other words, the second boom 413, via the second pivot axis 413A and the third pivot axis 417A, can be rotated in both a direction parallel to the rotation direction of the first boom 411 and a direction intersecting it. The second boom 413 is provided so as to be able to pivot relative to the first boom 411 in a direction intersecting the pivot direction of the first boom 411. Depending on the angle of rotation of the second boom 413, it is provided so as to be able to pivot to a first pivot position which is a retracted position relative to the first boom 411 as shown in Figure 4, a second pivot position which is an intermediate position relative to the first boom 411 as shown in Figure 5, and a third pivot position which is an advanced position relative to the first boom 411 as shown in Figure 6.

[0024] The second cylinder 416 is a hydraulic cylinder and connects the first boom 411 to the other end of the first connecting body 412. The second cylinder 416 is for vertical rotation of the first connecting body 412 around the second pivot shaft 413A. The third cylinder 417 is a forward and backward rotating cylinder, made of hydraulic material, and connects the first connecting body 412 and the second boom 413. The third cylinder 417 is for the forward and backward rotation of the second boom 413 relative to the first boom 411. The extension and retraction of the stroke of the third cylinder 417 drives the extension and retraction mechanism 41 to rotate in the forward and backward direction when the mast frame 21 is in its normal position.

[0025] The fourth cylinder 418 is a hydraulic cylinder and connects the second connecting body 414 to the working section 51, which will be described later. The fourth cylinder 418 is for the vertical rotation of the working section 51. As shown in Figure 8, each of the first cylinder 415, second cylinder 416, third cylinder 417, and fourth cylinder 418 has a rod-side chamber (415b, 416b, 417b, 418b) and a bottom-side chamber (415a, 416a, 417a, 418a).

[0026] 51 is a working section. The working section 51 is located at the other end of the second connecting body 414 and on the front side of the second connecting body 414 in the direction of travel. The working section 51 is further rotatable in the vertical direction relative to the second connecting body 414. In this embodiment, the work unit 51 has multiple blades arranged on a rotating shaft 512, which is a rotor shaft oriented perpendicular to the direction of travel, when the mast frame 21 is in its normal position, and performs ground work such as mowing by rotating the multiple blades. 514 is a cover that surrounds the rotating shaft 512 and covers the upper side of the rotating shaft 512 in the working state.

[0027] The working section 51 is attached to the second boom 413 via the second connecting body 414. The working section 51 is also provided with a fourth pivot axis 418A, which is a working section pivot axis oriented in the forward and backward directions of travel, and is provided on the second connecting body 414 so as to be able to pivot relative to the second connecting body 414. The second connecting body 414 does not tilt in the forward and backward directions relative to the direction of travel even when the second boom 413 pivots around the third pivot axis 417A, due to a link mechanism (not shown) provided on the second boom 413. That is, the fourth pivot axis 418A is always kept parallel to the direction of travel so that the left and right ends of the working section 51 do not tilt in the forward and backward directions relative to the direction of travel. The working section 51 is able to pivot relative to the second boom 413.

[0028] The first boom 411 is driven by the first cylinder 415, the first connecting body 412 by the second cylinder 416, the second boom 413 by the third cylinder 417, and the working section 51 by the fourth cylinder 418, each of which is capable of pivoting. Each cylinder is connected to a directional control valve 25. The directional control valve 25 operates each of the aforementioned cylinder groups by receiving command signals from a control unit t located in close proximity to the work machine A.

[0029] In Figure 9, u represents the operating unit. The operating unit u is installed on the traveling machine and operates the directional control valve 25 via the control unit t. The operating unit u is equipped with an operating lever u3 and an operating button B consisting of a plurality of first buttons B1, second buttons B2, third buttons B3, and fourth buttons B4 located at the tip of the operating lever u3. The operating unit u is also equipped with a pressure switch operating switch u1 and a floating switch u2, which is a floating means. The operating lever u3 operates the directional control valve 25 for operating the first boom 411, the first connecting body 412, and the second boom 413.

[0030] The floating switch u2, which is a floating means, puts the work section 51 into a floating mode or a floating deactivation state. When the work section 51 is in the floating mode, the extended work section 51 moves up and down freely without being operated by the operating lever u3, so that it can follow the unevenness of the work surface as it moves. The operating lever u3 operates the directional control valve 25, which can extend and retract the first cylinder 415, the second cylinder 416, the third cylinder 417, and the fourth cylinder 418, respectively.

[0031] As shown in Figure 9, the control unit u can be used to rotate the first boom 411, the first connecting body 412, the second boom 413, and the working unit 51 by tilting the control lever u3 forward (first direction D1), backward (second direction D2), left (third direction D3), and right (fourth direction D4) corresponding to the direction of travel, or by operating the control buttons B corresponding to the direction of travel: the forward button (first button B1), the backward button (second button B2), the left button (third button B3), and the right button (fourth button B4).

[0032] In this embodiment, when the operating lever u3 is moved forward (first direction D1), the first boom 411 rotates around the first pivot axis 411A toward the retracted side, and when moved backward (second direction D2), it rotates toward the deployed side. Also, when the operating lever u3 is moved to the left (third direction D3), the connecting body, consisting of the first pivot axis 411A and the second boom 413, rotates toward the deployed side around the second pivot axis, and when moved to the right (fourth direction D4), it rotates toward the retracted side.

[0033] Of the operation buttons B, operating the forward button (first button B1) causes the second boom 413 to rotate forward at its other end around the third pivot axis 417A, and operating the rear button (second button B2) causes the other end of the second boom 413 to rotate backward. Operating the left button (third button B3) causes the work unit 51 to rotate in the deployment direction around the fourth pivot axis 418A, which is the pivot axis of the work unit 51, and operating the right button (fourth button B4) causes the work unit 51 to rotate in the storage direction around the fourth pivot axis 418A. In the illustrated rotational directions, the deployment side of the first boom 411 refers to rotation to the left with the first pivot axis 411A as the pivot point when viewed from the rear in the direction of travel, and the retraction side of the first boom 411 refers to rotation to the right with the first pivot axis 411A as the pivot point when viewed from the rear in the direction of travel. Furthermore, in the illustrated rotational directions, the deployment side of the second boom 413 refers to rotation to the right with the second pivot axis 413A as the pivot point when viewed from the rear in the direction of travel, and the retraction side of the second boom 413 refers to rotation to the left with the second pivot axis 413A as the pivot point when viewed from the rear in the direction of travel. Furthermore, in the illustrated rotational directions, the deployment side of the working section 51 refers to rotation to the left with the fourth pivot axis 418A as the pivot point when viewed from the rear in the direction of travel, and the retraction side of the working section 51 refers to rotation to the right with the fourth pivot axis 418A as the pivot point when viewed from the rear in the direction of travel.

[0034] A hydraulic circuit according to an embodiment of this invention will be described with reference to Figure 8. c is the first relief valve (first pilot relief valve). The directional control valve 25 consists of a directional control valve 251 for the first cylinder, a directional control valve 252 for the second cylinder, a directional control valve 253 for the third cylinder, and a directional control valve 254 for the fourth cylinder. The directional control valve 25 is a valve that operates by an electrical signal, and its operation is controlled by a control unit t. The directional control valve 25 controls the fluid flowing into and out of the first cylinder 415, second cylinder 416, third cylinder 417, and fourth cylinder 418, switching between the direction in which the first cylinder 415, second cylinder 416, third cylinder 417, and fourth cylinder 418 extend, or the direction in which they shorten. The first relief valve c is provided in the directional control valve 25. The first relief valve c has the function of automatically opening at a set pressure and reducing the pressure. The first relief valve c is a pressure relief valve or safety relief valve that releases pressure when abnormal pressure occurs in the fluid in the circuit within the directional control valve 25.

[0035] From the tank (oil tank) 31, via the hydraulic pump, which is the fluid pressure generating source 24, it is connected to the directional control valve 25. Inside the directional control valve 25, it is sequentially connected to the directional control valve 254 for the fourth cylinder, the directional control valve 253 for the third cylinder, the directional control valve 252 for the second cylinder, and the directional control valve 251 for the first cylinder.

[0036] Within the directional control valve 25, the first cylinder directional control valve 251, the second cylinder directional control valve 252, the third cylinder directional control valve 253, and the fourth cylinder directional control valve 254 are connected to an unload circuit (no-load circuit) h that returns the fluid flowing into the first cylinder directional control valve 251, the second cylinder 416, and the forward and backward rotating cylinders, the third cylinder 417 and the fourth cylinder 418, respectively, back to the tank (oil tank) 31 when there is no operation by the operating unit u. The first cylinder 415 is connected to a directional control valve 251 that controls the fluid flowing into and out of the first cylinder 415. The directional control valve 251 controls the fluid flowing into and out of the first cylinder 415.

[0037] One end of the first relief valve c is connected to an unload circuit h that returns fluid to the tank (oil tank) 31 side when the operating unit u is not operated, from the respective directional control valves 25: the directional control valve 251 for the first cylinder, the directional control valve 252 for the second cylinder, the directional control valve 253 for the third cylinder, and the directional control valve 254 for the fourth cylinder. The other end of the first relief valve c is connected to the directional control valves 25: the directional control valves 251 for the first cylinder, the directional control valve 252 for the second cylinder, the directional control valve 253 for the third cylinder, and the directional control valve 254 for the fourth cylinder via first check valves 251a, second check valve 252a, third check valve 253a, and fourth check valve 254a, which can suppress the inflow of fluid from the directional control valves 251 for the first cylinder, the directional control valve 252 for the second cylinder, the directional control valve 253 for the third cylinder, and the directional control valve 254 for the fourth cylinder to the first relief valve c side. The other end of the first relief valve c is also connected to the tank (oil tank) 31.

[0038] As shown in Figure 8, the first cylinder 415 has a rod-side chamber 415b and a bottom-side chamber 415a. The second cylinder 416 has a rod-side chamber 416b and a bottom-side chamber 416a. The third cylinder 417 has a rod-side chamber 417b and a bottom-side chamber 417a. The fourth cylinder 418 has a rod-side chamber 418b and a bottom-side chamber 418a.

[0039] The directional control valve 251 for the first cylinder is connected to the rod-side chamber 415b and the bottom-side chamber 415a of the first cylinder 415, respectively. The directional control valve 252 for the second cylinder is connected to the rod-side chamber 416b and the bottom-side chamber 416a of the second cylinder 416, respectively. The directional control valve 253 for the third cylinder is connected to the rod-side chamber 417b and the bottom-side chamber 417a of the third cylinder 417, respectively. The directional control valve 254 for the fourth cylinder is connected to the rod-side chamber 418b and the bottom-side chamber 418a of the fourth cylinder 418, respectively.

[0040] The directional control valve 251 for the first cylinder is configured to allow connection of a circuit from the directional control valve 251 for the first cylinder to the first cylinder 415 and a circuit from the directional control valve 251 for the first cylinder to the tank (oil tank) 31.

[0041] The directional control valve 252 for the second cylinder is configured to allow connection of a circuit from the directional control valve 252 to the second cylinder 416 and a circuit from the directional control valve 252 to the tank (oil tank) 31. The directional control valve 253 for the third cylinder is configured to allow connection of a circuit from the directional control valve 253 to the third cylinder 417 and a circuit from the directional control valve 253 to the tank (oil tank) 31. The directional control valve 254 for the fourth cylinder is configured to allow connection of a circuit from the directional control valve 254 to the fourth cylinder 418 and a circuit from the directional control valve 254 to the tank (oil tank) 31.

[0042] In this embodiment, the directional control valves 25 for controlling the first cylinder 415 to the fourth cylinder 418, namely the first cylinder directional control valve 251, the second cylinder directional control valve 252, the third cylinder directional control valve 253, and the fourth cylinder directional control valve 254, block the circuit within the directional control valves 25, namely the first cylinder directional control valve 251, the second cylinder directional control valve 252, the third cylinder directional control valve 253, and the fourth cylinder directional control valve 254, when no switching operation is performed by the operating unit u, so as to prevent the fluid transferred from the fluid pressure source 24 from flowing in or out of the first cylinder 415 to the fourth cylinder 418 through the directional control valves 254.

[0043] When a switching operation is performed by the control unit u, the system is configured to allow fluid to flow from the fluid pressure source 24 to the first cylinder 415 through the fourth cylinder 418, and to flow from the first cylinder 415 through the fourth cylinder 418 to the tank (oil tank) 31. Furthermore, each of the directional control valves 25 used in this embodiment—the directional control valve 251 for the first cylinder, the directional control valve 252 for the second cylinder, the directional control valve 253 for the third cylinder, and the directional control valve 254 for the fourth cylinder—returns the fluid that is constantly being transported from the fluid pressure source 24 to the tank 31 via the unload circuit h when in a neutral state during non-operation.

[0044] The first cylinder directional control valve 251 has a circuit that goes from the first cylinder directional control valve 251 toward the tank 31 side, which is different from the unload circuit h, and a circuit that connects from the first cylinder directional control valve 251 to the first relief valve c and the unload circuit h via a check valve 251a that can suppress the inflow of fluid to one end of the first relief valve c. The second cylinder directional control valve 252 has a circuit that goes from the second cylinder directional control valve 252 toward the tank 31 side, which is different from the unload circuit h, and a circuit that connects from the second cylinder directional control valve 252 to the first relief valve c and the unload circuit h via a check valve 252a that can suppress the inflow of fluid to one end of the first relief valve c.

[0045] The third cylinder directional control valve 253 has a circuit that goes from the third cylinder directional control valve 253 toward the tank 31 side, which is different from the unload circuit h, and a circuit that connects from the third cylinder directional control valve 253 to the first relief valve c and the unload circuit h via a check valve 253a that can suppress the inflow of fluid to one end of the first relief valve c. The fourth cylinder directional control valve 254 has a circuit that goes from the fourth cylinder directional control valve 254 toward the tank 31 side, which is different from the unload circuit h, and a circuit that connects from the fourth cylinder directional control valve 254 to the first relief valve c and the unload circuit h via a check valve 254a that can suppress the inflow of fluid to one end of the first relief valve c.

[0046] The rod-side chamber 415b and the bottom-side chamber 415a of the first cylinder 415 are connected to the directional control valve 251 for the first cylinder, respectively. By switching the directional control valve 251 for the first cylinder, either the rod-side chamber 415b or the bottom-side chamber 415a of the first cylinder 415 is connected to the tank 31. The first cylinder 415 controls the directional control valve 251 for the first cylinder so that when the stroke is extended in the direction of the stroke end, fluid is drawn into the bottom chamber 415a and pushed out from the rod chamber 415b, and when the stroke is shortened, fluid is pushed out from the bottom chamber 415a and drawn into the rod chamber 415b. The first cylinder 415, by extending and retracting its stroke, rotates the first boom 411 which constitutes the extension / retraction mechanism 41, thereby raising or lowering the work section 51. The extension and retraction of the first cylinder 415 is controlled by a directional control valve 25 having a first relief valve c.

[0047] The rod-side chamber 416b and the bottom-side chamber 416a of the second cylinder 416 are connected to the second cylinder directional control valve 252, respectively. By switching the second cylinder directional control valve 252, either the rod-side chamber 416b or the bottom-side chamber 416a of the second cylinder 416 is connected to the tank 31. The second cylinder 416 controls the directional control valve 252 for the second cylinder so that when the stroke is extended in the direction of the stroke end, fluid is drawn into the bottom chamber 416a and pushed out from the rod chamber 416b, and when the stroke is shortened, fluid is pushed out from the bottom chamber 416a and drawn into the rod chamber 416b. The second cylinder 416, by extending and retracting its stroke, rotates the first connecting body 412 that constitutes the extension / retraction mechanism 41, thereby raising or lowering the work section 51. The extension and retraction of the second cylinder 416 is controlled by a directional control valve 25 having a first relief valve c.

[0048] The rod-side chamber 417b and the bottom-side chamber 417a of the third cylinder 417 are connected to the third cylinder directional control valve 253, respectively. By switching the third cylinder directional control valve 253, either the rod-side chamber 417b or the bottom-side chamber 417a of the third cylinder 417 is connected to the tank 31. The third cylinder 417 controls the third cylinder directional control valve 253 so that when the stroke is extended in the stroke end direction, fluid is drawn into the bottom chamber 417a and pushed out from the rod chamber 417b, and when the stroke is shortened, fluid is pushed out from the bottom chamber 417a and drawn into the rod chamber 417b. The third cylinder 417, through the extension and retraction of its stroke, rotates the second boom 413, which constitutes the extension and retraction mechanism 41, in the forward and backward directions when the mast frame 21 is in its normal state. The extension and retraction of the third cylinder 417 is controlled by a directional control valve 25 having a first relief valve c.

[0049] The rod-side chamber 418b and the bottom-side chamber 418a of the fourth cylinder 418 are connected to the directional control valve 254 for the fourth cylinder, respectively. By switching the directional control valve 254 for the fourth cylinder, either the rod-side chamber 418b or the bottom-side chamber 418a of the fourth cylinder 418 is connected to the tank 31. The fourth cylinder 418 controls the directional control valve 254 for the fourth cylinder so that when the stroke is extended in the direction of the stroke end, fluid is drawn into the bottom chamber 418a and pushed out from the rod chamber 418b, and when the stroke is shortened, fluid is pushed out from the bottom chamber 418a and drawn into the rod chamber 418b. The fourth cylinder 418, through the extension and retraction of its stroke, drives the working section 51 to rotate vertically relative to the second connecting body 414 when the mast frame 21 is in its normal state. The extension and retraction of the fourth cylinder 418 is controlled by a directional control valve 25 having a first relief valve c.

[0050] The first cylinder 415, the second cylinder 416, the third cylinder 417, and the fourth cylinder 418 all use the first relief valve c in common. The directional control valve 25 can be switched to either extend or retract the first cylinder 415, second cylinder 416, third cylinder 417, and fourth cylinder 418, thereby supplying fluid pressure generated by the pump 24 to the first cylinder 415, second cylinder 416, third cylinder 417, and fourth cylinder 418, and driving each cylinder to extend or retract.

[0051] Furthermore, the directional control valve 25 may also have a neutral position that connects the pressurized fluid from the pump 24 back to the return circuit on the tank 31 side to unload the fluid, and also has a circuit that connects to the bottom chamber 415a and rod chamber 415b of the cylinder 415 and communicates with the tank 31.

[0052] When a neutral circuit, which is in a neutral position and communicates with the tank 31, is provided in the circuit of the directional control valve 25, the fluid in the rod-side chamber 415b and the bottom-side chamber 415a of the cylinder 415 can freely move between each other, so that the cylinder 415 can be extended and retracted. When the floating switch u2 is operated to put the device into a floating operation state, the first boom 411 can move freely up and down, so that the work section 51 can follow the unevenness of the work surface as it moves.

[0053] The control unit t shown in Figure 10 is connected to the directional control valves 25, including the directional control valve 251 for the first cylinder, the directional control valve 252 for the second cylinder, the directional control valve 253 for the third cylinder, and the directional control valve 254 for the fourth cylinder, and controls their operation. As shown in Figure 10, the control unit t is connected to the notification unit q, the receiving unit o, the first sensor Se1, the second sensor Se2, the first switch Sw1, and the second switch Sw2. The control unit t receives the operation signals from the operation unit u, which are generated by the operation of the manually operated operation lever u3 and operation button B, at the receiving unit o. The control unit t then takes these operation signals as input and outputs an operation signal to the directional control valve 25 to operate the directional control valve 25.

[0054] When the directional control valve 25 receives an operating signal output from the control unit t, it operates the directional control valve 251 for the first cylinder, the directional control valve 252 for the second cylinder, the directional control valve 253 for the third cylinder, and the directional control valve 254 for the fourth cylinder based on the operation of the operating lever u3 and the operating button B, thereby controlling the fluid flowing into and out of the first cylinder 415, the second cylinder 416, the third cylinder 417, and the fourth cylinder 418. When the control unit t receives a signal transmitted in response to the operation of the operating unit u, it controls the operation of the directional control valve 25 via the control unit t.

[0055] When the operation lever u3 and operation button B are operated manually, the operation signal transmitted from the operation unit u is received by the receiving unit o and sent to the control unit t, and input to the control unit t. Upon receiving the operation signal, the control unit t then outputs an operation signal to operate the other components. The operation signal output by the control unit t controls the operation of the directional control valve 25 to move the end of the telescopic means 41 in an upward or downward direction. The operation signal also controls the operation of the directional control valve 25 to move the end of the telescopic means 41 in leftward and rightward directions relative to the direction of travel, as well as in forward and reverse directions. The directional control valves 25 are valves that operate by electrical signals, and their operation is controlled by the control unit t. The operating unit u is shown to operate various valves via wireless transmission through the control unit t, but it may also be wired.

[0056] Upon receiving the operation signal, the control unit t outputs an operation signal to operate the directional control valve 25. Upon receiving this operation signal, the directional control valve 25 switches the circuit to supply fluid to the first cylinder 415, second cylinder 416, third cylinder 417, and fourth cylinder 418 in order to raise or lower the working section 51 provided at the other end of the telescopic means 41, or move it to the left or right relative to the direction of travel, or move it forward or backward, or turn it to the left or right relative to the direction of travel. In the working state embodiment, the upward movement of the working section 51 is caused by switching the circuit to pump fluid from the directional control valve 251 to the bottom-side chamber 415a, and the downward movement of the working section 51 is caused by switching the circuit to pump fluid from the directional control valve 251 to the rod-side chamber 415b.

[0057] Furthermore, the leftward movement of the work unit 51 is performed by switching the circuit to pump fluid from the directional control valve 252 to the bottom-side chamber 416a, and the rightward movement of the work unit 51 is performed by switching the circuit to pump fluid from the directional control valve 252 to the rod-side chamber 416b. Furthermore, the forward movement of the work unit 51 is achieved by switching the circuit to pump fluid from the directional control valve 253 to the bottom chamber 417a, and the reverse movement of the work unit 51 is achieved by switching the circuit to pump fluid from the directional control valve 253 to the rod chamber 417b. Furthermore, leftward rotation around the fourth pivot axis 418A, as viewed from the rear in the direction of travel of the work unit 51, is performed by switching the circuit to pump fluid from the directional control valve 254 to the bottom chamber 418a, and rightward rotation around the fourth pivot axis 418A, as viewed from the rear in the direction of travel of the work unit 51, is performed by switching the circuit to pump fluid from the directional control valve 254 to the rod chamber 418b.

[0058] The control unit t can send operating signals to various valves and other components that require electrical control. The transmitted operating signals can then be used to send signals to operate notification units (speakers and other audio equipment) q, display units (not shown, such as display devices and lamps), and the like. The first boom 411 is equipped with a first sensor Se1. The first sensor Se1 consists of a potentiometer and constantly detects the slewing angle of the first boom 411 around the first slewing axis 411A relative to the mast frame 21.

[0059] Se11 is the first sensor arm. The first sensor arm Se11 protrudes from the first sensor Se1. The first sensor Se1 is an angle measuring device that detects the amount of rotational angle displacement, which is the amount by which the first boom 411 moves, by the rotation of the first sensor arm Se11 connected to the first boom 411, and outputs the detected value. In this embodiment, the first sensor Se1 is provided with a rotatable first sensor arm Se11 for angle detection, and has an elongated first detection hole Se13 at its tip. By positioning a first pin-shaped part Se12 fixed to the mast frame 21 within the first detection hole Se13, the first sensor arm Se11 rotates around the first sensor Se1 as the first boom 411 rotates, and the rotation angle of the first boom 411 is detected.

[0060] The first sensor Se1 is configured to transmit the detected first angle signal to the control unit t. Since the first boom 411 is attached to the main frame 11 via the mast frame 21, the first sensor Se1 detects the slewing angle of the first boom 411 relative to the main frame 11 as it slewing around the first slewing axis 411A. The first sensor Se1 constantly detects the relative angle of the first boom 411 with respect to the mast frame 21.

[0061] The first connecting body 412 is equipped with a second sensor Se2 near the second pivot axis 413A. Se21 is a second sensor arm. The second sensor arm Se21 protrudes from the second sensor Se2. The second sensor Se2 is an angle measuring device that detects the amount of rotational angle displacement, which is the amount by which the first boom 411 has moved, by the rotation of the second sensor arm Se21 connected to the first boom 411, and outputs the detected value.

[0062] The second sensor Se2 consists of a potentiometer and constantly detects the rotation angle of the first connecting body 412, which rotates around the second pivot axis 413A relative to the first boom 411. In this embodiment, the second sensor Se2 is provided with a second sensor arm Se21 for angle detection that is rotatable relative to the second sensor Se2, and has an elongated second detection hole Se23 at its tip. By positioning the second pin-shaped part Se22, which is fixed to the tip of the other end of the first boom 411, within the second detection hole Se23, the second sensor arm Se21 rotates around the second sensor Se2 as the first connecting body 412 rotates around the second pivot axis 413A, and the second sensor Se2 detects the rotation angle of the first connecting body 412 relative to the first boom 411. The second sensor Se2 transmits the detected second angle signal to the control unit t. The second sensor Se2 can continuously detect the relative angle between the first connecting body 412 and the second boom 413 with respect to the first boom 411.

[0063] The first switch Sw1 and the second switch Sw2 will be explained with reference to Figures 4 to 6, which are enlarged views of the vicinity of the third slewing axis 417A of the work machine A according to the embodiment, as seen from the axial direction of the third slewing axis 417A. A first switch Sw1 and a second switch Sw2 are provided near the third pivot axis 417A of the first connecting body 412. The first switch Sw1 and the second switch Sw2 are each composed of limit switches and open and close the circuit by physical contact. The first switch Sw1 and the second switch Sw2 are attached to a mounting base Sw3 provided on the first connecting body 412. The opening and closing operation of this circuit allows the first switch Sw1 to transmit a first contact signal and the second switch Sw2 to transmit a second contact signal to the control unit t. The second switch Sw2 is positioned radially away from the first switch Sw1 with respect to the radial direction of the third pivot axis 417A. The first switch Sw1 and the second switch Sw2 are positioned approximately the same with respect to the circumferential direction of the third pivot axis 417A. The control unit u can detect the first pivot position, which is the reverse position of the second boom 413, the second pivot position, which is the intermediate position, and the third pivot position, which is the forward position, of the second boom 413 as shown in Figures 4 to 6, based on the presence or absence of the first and second contact signals transmitted from the first switch Sw1 and the second switch Sw2, and their combinations.

[0064] The first working part F1 and the second working part F2 will be described based on Figures 4 to 6. As shown in Figures 4 to 6, a first working part F1 and a second working part F2 are provided on one end of the second boom 413. The first working part F1 is a portion that protrudes radially from one end of the second boom 413 with respect to the radial direction of the third pivot axis 417A, and can contact the first switch Sw1 when the second boom 413 rotates around the third pivot axis 417A. The first working part F1 has a protruding tip. Contact of the first working part F1 with the first switch Sw1 includes not only contact of the protruding portion of the first working part F1 with the first working part F1, but also contact of the base portion and root portion of the protruding portion with the first working part F1.

[0065] The second working part F2 is a portion that protrudes radially from one end of the second boom 413 with respect to the radial direction of the third pivot axis 417A, and is positioned further away from the first working part F1 in the radial direction with respect to the third pivot axis 417A. The second working part F2 is positioned differently from the first working part F1 in relation to the circumferential direction of the third pivot axis 417A.

[0066] The contact and non-contact states between the first operating part F1 and the first switch Sw1, and the contact and non-contact states between the second operating part F2 and the second switch Sw2 will be explained. As described above, the second boom 413 is provided so as to be able to rotate relative to the first boom 411 in a direction intersecting the rotation direction of the first boom 411. Depending on the rotation angle of the second boom 413, it is provided so as to be able to rotate to a first rotation position which is a retracted position relative to the first boom 411 as shown in Figure 4, a second rotation position which is an intermediate position relative to the first boom 411 as shown in Figure 5, and a third rotation position which is an advanced position relative to the first boom 411 as shown in Figure 6.

[0067] When the second boom 413 shown in Figure 4 is in the first slewing position, which is the retracted position, the first operating part F1 does not contact the first switch Sw1, and the second operating part F2 does not contact the second switch Sw2. When the second boom 413 is in the intermediate second slewing position shown in Figure 5, due to the slewing of the second boom 413 around the third slewing axis 417A relative to the first connecting body 412, the first operating part F1 is in contact with the first switch Sw1, while the second operating part F2 is not in contact. When the second boom 413, as shown in Figure 6, is in the forward position (third pivot position) due to rotation around the third pivot axis 417A relative to the first connecting body 412 from the state shown in Figure 5, the first operating part F1 contacts the first switch Sw1, and the second operating part F2 contacts the second switch Sw2.

[0068] When the second boom 413 rotates from the first rotating position, which is the retracted position, to the third rotating position, which is the advanced position, the first switch Sw1 is operated by contact with the first operating part F1 at the second rotating position, which is the intermediate position, and then continues to be operated while rotating towards the third rotating position, which is the advanced position. Since the second working part F2 and the first working part F1 are positioned at different locations relative to the circumferential direction of the third pivot axis 417A, the pivot angle of the second boom 413 at which the first switch Sw1 makes contact and emits a first contact signal can be made different from the pivot angle of the second boom 413 around the third pivot axis 417A at which the second switch Sw2 makes contact and emits a second contact signal.

[0069] In this embodiment, the first switch Sw1 and the second switch Sw2 are positioned at approximately the same location relative to the circumferential direction of the third pivot axis 417A, while the first and second operating parts F1 and F2 are positioned at different locations relative to the circumferential direction of the third pivot axis 417A. However, the invention is not limited to this example. It is sufficient that the angle at which the first and second switches Sw1 and Sw2 are operated by the first and second operating parts F1 and F2 differs as the second boom 413 rotates around the third pivot axis 417A. For example, the first and second switches Sw1 and Sw2 may be positioned at different locations relative to the circumferential direction of the third pivot axis 417A, while the first and second operating parts F1 and F2 may be positioned at approximately the same location relative to the circumferential direction of the third pivot axis 417A to create a correspondence. In this explanation, the state in which the first switch Sw1 is in contact with the first actuation part F1 is sometimes referred to as the ON state, and the state in which the first switch Sw1 is not in contact with the first actuation part F1 is sometimes referred to as the OFF state. Similarly, the state in which the second switch Sw2 is in contact with the second actuation part F2 is sometimes referred to as the ON state, and the state in which the second switch Sw2 is not in contact with the second actuation part F2 is sometimes referred to as the OFF state.

[0070] Let's explain the storage position of implement A. The stowed position refers to a state in which the first boom 411 is horizontally tilted over the mast frame 21 or main frame 11, and the second boom 413 is positioned so as to overlap or fold over the first boom 411, and the second boom 413 is rotated to the first slewing position (retracted position) as shown in Figures 1 and 4, and the working section 51 is positioned so as to overlap or fold over the second boom 413. In the front view shown in Figure 1, the working section 51 in the stowed position has its rotation axis 512 parallel to the first boom 411 and the second boom 413. Also, the top surface of the cover 514 during operation is directed toward the second boom 413 by slewing around the fourth slewing axis. The stowed position is sometimes also called the stowed position.

[0071] The horizontal plane used in this description of the present invention is used to conveniently represent the running surface of the mobile vehicle in order to explain it in reference to the illustrated drawings, and is different from the horizontal plane used in relation to the direction of gravity. In the stowed position of work implement A, the stowed work section 51 of work implement A according to this embodiment is folded and stored at the rear of the traveling machine body.

[0072] The deployment position of implement A will be explained. The deployed position of implement A consists of the following states: (1) The first boom 411 in the stowed position is rotated around the first pivot axis 411A and rotated toward the deployed side so that it rises relative to the mast frame 21 or main frame 11, so that the other end of the first boom 411 is positioned laterally relative to the mast frame 21 or main frame 11. (2) The second boom 413 is rotated from a folded state relative to the first boom 411 to an unfolded state around the second pivot axis 413A, widening the angle between them. (3) The second boom 413 is rotated around the third pivot axis 417A, as shown by the solid line in Figure 3, and is in the forward position, the third pivot position, as shown in Figures 6 and 7. (4) The working section 51 is rotated around the fourth pivot axis 418A, and the second boom 413 is rotated in the deployment direction, which is the direction in which it is extended from one end to the other. It refers to. The deployed stance is sometimes referred to as the deployed position or home position.

[0073] The deployed position of implement A is the third slewing position (forward position) as shown on the side of implement A in Figure 3, and the second boom 413 is in the working section 51 position (51-3) shown by the solid line. In the first slewing position (retracted position), the second boom 413 is at the working section 51 position of the dashed-dot line section 51-1. In the second slewing position (intermediate position), the second boom 413 is at the working section position of the dashed-dot line section 51-2. At the work position, the worker can freely choose to operate the second boom 413 in the first slewing position (retracted), the second slewing position (intermediate), or the third slewing position (advance).

[0074] Figures 4 to 6 illustrate the change in the position of the third pivot axis 417A in the vicinity of the third pivot axis 417A, as viewed from the axial direction of the third pivot axis 417A, from the first pivot position (retracted position) to the third pivot position (advancing position). Figure 4 shows a close-up view of the vicinity of the third slewing axis 417A of the work machine A according to the embodiment, as seen from the axial direction of the third slewing axis 417A, with the second boom 413 in the first slewing position (retracted position). In the first slewing position (retracted position), there is no contact between the first actuation part F1 of the first switch Sw1 and the second actuation part F2 of the second switch Sw2. In other words, the control unit t does not receive either the first contact signal or the second contact signal. The control unit t is configured to determine that the second boom 413 is in the first slewing position (retracted position) in this state.

[0075] Figure 5 shows a close-up view of the vicinity of the third slewing axis 417A of the work machine A according to the embodiment, as seen from the axial direction of the third slewing axis 417A, with the second boom 413 in the second slewing position (intermediate position). In the second slewing position (intermediate position), the first switch Sw1 is in contact with the first operating part F1, and the second switch Sw2 is not in contact with the second operating part F2. In other words, the control unit t receives the first contact signal, but does not receive the second contact signal. The control unit t is configured to determine that the second boom 413 is in the second slewing position (intermediate position) in this state.

[0076] Figure 6 shows a close-up view of the vicinity of the third slewing axis 417A of the work machine A according to the embodiment, as seen from the axial direction of the third slewing axis 417A, where the second boom 413 is in the forward position, which is the third slewing position. Figure 7 shows an enlarged side view of the third pivot axis 417A of the work machine A according to the embodiment, showing the third pivot position when the second boom 413 is in the forward position. Both the first switch Sw1 and the second switch Sw2 are operated. In the third slewing position, which is the forward position, the first switch Sw1 is in contact with its first operating part F1, and the second switch Sw2 is in contact with its second operating part F2. In other words, the control unit t receives both the first contact signal and the second contact signal. The control unit is configured to determine that this state is the third slewing position, which is the forward position of the second boom 413.

[0077] The control unit is configured to detect only the switching operation of the first switch Sw1 and the second switch Sw2. This allows the rotational position of the second boom 413, which rotates around the third pivot axis 417A, to be recognized with a simple configuration. By recognizing the opening and closing of the circuits of the two switches Sw1 and Sw2 and their combinations, it becomes possible to determine the three rotational positions of the second boom 413.

[0078] The detection method using the second switch Sw2 of the first switch Sw1 eliminates the need to constantly detect and calculate the rotation angle of all movable parts, unlike the detection method for the rotation angle of the first boom 411 using the first sensor Se1 and the detection method for the rotation angle of the first connecting body 412 using the second sensor Se2. This reduces the computational burden on the control unit t. As a result, the group of devices involved in calculations within the control unit t can be made simpler.

[0079] In the illustrated embodiment, the first working part F1 and the second working part F2 are shown as being integrated near the fulcrum of the second boom 413, but they may also be provided as separate parts that can be attached as needed.

[0080] This document will explain the operation and effects of an embodiment of this invention, which describes a "work machine capable of preventing unintended movements while reducing the computational burden related to the posture control of movable parts." As described above, the second boom 413 is provided so as to be able to rotate relative to the first boom 411 in a direction intersecting the rotation direction of the first boom 411. Depending on the rotation angle of the second boom 413, it is provided so as to be able to rotate to a first rotation position which is a retracted position relative to the first boom 411 as shown in Figure 4, a second rotation position which is an intermediate position relative to the first boom 411 as shown in Figure 5, and a third rotation position which is an advanced position relative to the first boom 411 as shown in Figure 6.

[0081] As shown in Figure 6, the second boom 413, in the third slewing position which is the forward position, is pressing the first switch Sw1 with the first operating part F1 and the second switch Sw2 with the second operating part F2. When an operator operates the control unit to rotate the second boom 413, as shown in Figure 4, from a location other than the first slewing position which is the retracted position toward the first slewing position which is the retracted position, the control unit t switches the directional control valve and operates the cylinder (third cylinder 417) to rotate the second boom 413 toward the reverse side which is the first slewing position which is the retracted position.

[0082] As the second boom 413 moves toward the first slewing position, which is the retracted position shown in Figure 4, it passes through the second slewing position, which is the intermediate position shown in Figure 5, before reaching the first slewing position, which is the retracted position shown in Figure 4. At the second slewing position, which is the intermediate position, the first actuation part F1 continues to press the first switch Sw1, but the second actuation part F2 releases the pressure on the second switch Sw2. Then, as the rotation of the second boom 413 continues and it reaches the first slewing position, which is the retracted position shown in Figure 4, the pressure on the first switch Sw1 at the first actuation part F1 is released. In this embodiment, at the first slewing position, which is the retracted position, the stroke end of the third cylinder 417 is provided, or a slewing restriction is provided near the third slewing axis, so that the second boom 413 cannot be physically moved backward from the first slewing position, which is the retracted position shown in Figure 4.

[0083] The control unit t, having received a detection signal that the first switch Sw1 has been pressed, determines that the second boom 413 is in the intermediate position, the second slewing position, when the detection signal of the second switch Sw2 switches to a release signal. Furthermore, while still recognizing the second boom 413 as being in the intermediate position, the control unit t rotates the second boom 413 and presses the second switch Sw2, causing the detection signal of the second switch Sw2 to switch to a press signal, and determines that the position is the forward position, the third slewing position. Then, while recognizing the second boom 413 as being in the intermediate position, the second slewing position, the second boom 413 is slewing and the pressure on the first switch Sw1 is released. This causes the detection signal of the first switch Sw1 to switch from a pressed state to a released state, prompting the control unit t to determine that the second boom 413 is in the first slewing position, which is the retracted position shown in Figure 4. Furthermore, in this embodiment, the control unit t recognizes that the second boom 413 is in the first slewing position, which is the retracted position shown in Figure 4, as soon as the pressure on the first switch Sw1 is released, thereby simplifying signal processing.

[0084] Furthermore, when the second boom 413 stops rotating between the first rotation position (retracted position) and the third rotation position (advancing position) as shown in Figure 4, the control unit t stores the position of the second boom 413 based on detection signals detected from the pressing state of the first switch Sw1 and the second switch Sw2. Then, when operating the second boom 413 again, it can determine its own position.

[0085] (1) We will explain the case of a malfunction in recognizing the first turning position, which is the reversing position shown in Figure 4. In the above configuration, we assume a scenario where the control unit t cannot recognize the signal switching caused by pressing and releasing the first switch Sw1 due to a break in the circuit from the first switch Sw1 to the control unit t, an internal malfunction of the first switch Sw1, or a physical abnormality of the second boom 413.

[0086] When the vehicle is turned from the first turning position, which is the reversed position as shown in Figure 4, to the second turning position, which is the intermediate position, the detection signal of the first switch Sw1 does not switch, which can lead to the vehicle overshooting the target point, the second turning position, which is the intermediate position. Conversely, when the boom is rotated from the intermediate position, the second rotation position, or the forward position, the third rotation position, toward the retracted position, the first rotation position, as shown in Figure 4, the signal switching of the first switch Sw1 may not occur properly. As a result, the control unit t may mistakenly perceive that the second boom 413 is in the retracted position, the first rotation position, as shown in Figure 4, even though it is not actually in that position. The control unit t's misidentification of the first slewing position, which is the retracted position shown in Figure 4, is a major inconvenience. If the control unit t rotates the first boom 411 toward the stowed position, even though it is not actually in the first slewing position, there is a risk that the second boom 413 and the work unit 51 attached to the tip of the second boom 413 may come too close to or come into contact with the traveling machine (tractor) located in front of the main frame 11.

[0087] The solution to the above problem will be explained. To resolve the above-mentioned inconveniences, the present invention controls the second boom 413 using the following control method. First, when the second boom 413 is in a pivot position other than the first pivot position which is the retracted position shown in Figure 4, and the control unit receives an operation command to move the second boom 413 toward the first pivot position which is the rearward side, the control unit t starts the control flow shown in Figure 11.

[0088] In S11, the control unit starts the timer at the same time that the second boom 413 begins moving toward the first slewing position, which is the retracted position shown in Figure 4. This timer measures the elapsed time, which is the set remaining time. In this embodiment, the timer is set to 8 seconds, which is the physical slewing time of the second boom 413 from the third slewing position, which is the forward position shown in Figure 4, to the first slewing position, which is the retracted position. The elapsed time set by this timer can be freely changed depending on the specifications and capabilities of the work machine. While the timer is running, the second boom 413 is slewing toward the first slewing position, which is the retracted position shown in Figure 4.

[0089] In S12, the control unit t then determines whether there has been a change in the detection signal of the first switch Sw1 within the elapsed time set by the timer. In this embodiment, the control unit t is configured to recognize that when the second boom 413 reaches the first slewing position, which is the retracted position shown in Figure 4, the first operating unit F1 has released its pressure on the first switch Sw1. The control unit t recognizes the change in the detection signal when it receives the change in the detection signal caused by the first switch Sw1 changing from a pressed state to a released state. In other words, if the second boom 413 reaches the first slewing position, which is the retracted position shown in Figure 4, the detection signal of the first switch Sw1 changes from a pressed state to a released state, so the control unit t recognizes the change in the detection signal and determines whether or not this change has occurred.

[0090] In S13, if the control unit t determines in S12 that there has been a change in the detection signal within the elapsed time, it processes the system as being in a normal state, with the switch itself and the circuit from the control unit t to the switch (first switch Sw1) being normal, the second boom 413 itself including the first operating part F1 being normal, and the components that drive the second boom 413 (cylinder, directional control valve, pumps, etc.) being normal.

[0091] In S13, the determination of a normal state generates a flag that signals permission for the operation of multiple other movable parts, including the second boom 413 in the next process, and terminates the process. This determination enables other control.

[0092] In S14, if the control unit t determines in S12 that there has been no change in the detection signal within the elapsed time, the switch (first switch Sw1) itself and the circuit from the control unit t to the switch (first switch Sw1) are processed as abnormal, the second boom 413 including the first operating part F1 is processed as abnormal, and the components that drive the second boom 413 (cylinder, directional control valve, pumps, etc.) are processed as being in an abnormal state. An abnormal flag is generated based on the determination of the abnormal state.

[0093] In S14, if an abnormal condition is determined, the abnormality flag prompts the control unit to stop the operation of the second boom 413 and issue a warning signal. Furthermore, since there are several other movable parts in addition to the second boom 413, the abnormality flag signals the control unit to stop the operation of these other movable parts as well, and in S15, a prohibition command is issued to make their operation impossible, thus terminating the process.

[0094] The control method described above allows the control unit t to determine whether the second boom 413 has reached the first slewing position, which is the retracted position shown in Figure 4, within the elapsed time, which is the physical slewing time of the second boom 413. This makes it possible to determine that the first switch Sw1, the second boom 413, and its drive unit are in an abnormal state. By using the first switch Sw1 and the second switch Sw2, the components that determine the position of the second boom 413 are simplified, reducing the load on these calculation processes, while also making it easier for the operator to identify the faulty part even if an abnormality occurs. As a result, the time required for repairs can be shortened.

[0095] Furthermore, if an abnormal condition is detected, the system is designed to stop the operation of all movable parts, thereby preventing the movable parts, including the second boom 413, from being unintentionally operated and coming dangerously close to or coming into contact with the mobile body or other components.

[0096] This control allows for the confirmation of the integrity of at least the first switch Sw1 when moving the second boom 413 from the position stored in the control unit t before the start of control to the first slewing position, which is the retracted position shown in Figure 4. More broadly, it also allows for the confirmation of the integrity of the second boom 413 and the drive mechanism that operates it. Therefore, it is possible to ensure that the first switch Sw1 operates reliably when the second boom 413 is positioned to the first slewing position, which is the retracted position shown in Figure 4, and to prevent malfunctions caused by a failure of the first switch Sw1.

[0097] The operation of the second boom 413 described applies not only when the second boom 413 is operated independently by the operating lever u3, but also when it is operated automatically by pressing a button that automatically operates all movable parts. In other words, it applies to all operations in which the second boom 413 rotates from a location other than the first rotation position, which is the retracted position shown in Figure 4, toward the first rotation position, which is the retracted position.

[0098] Furthermore, the control operation of the present invention is designed to be canceled if the operation by the control unit u is released during the control operation. The present invention makes it possible to prevent situations in which the second boom 413 comes into close proximity to the traveling machine when the control unit t fails to correctly recognize the change in the detection signal of the first switch Sw1 during operation, particularly when the switch is operated to the stowed position.

[0099] Therefore, in the embodiments of this invention, The first boom 411 is rotatably mounted on the mast frame 21, and the second boom 413 is rotatably mounted relative to the first boom 411 in a direction intersecting the rotation direction of the first boom 411. Depending on the angle of rotation of the second boom 413, it is rotatably mounted to a first rotation position which is a retracted position relative to the first boom 411 as shown in Figure 4, a second rotation position which is an intermediate position relative to the first boom 411 as shown in Figure 5, and a third rotation position which is an advanced position relative to the first boom 411 as shown in Figure 6.

[0100] The first switch Sw1 detects the second slewing position, which is the intermediate position of the second boom 413 as shown in Figure 5. The second switch Sw2 detects the third slewing position, which is the forward position of the second boom 413 as shown in Figure 6. The control unit t is connected to the first switch Sw1 and the second switch Sw2, and by receiving detection signals from the first switch Sw1 and the second switch Sw2, it can recognize the first slewing position, which is the retracted position of the second boom 413, the second slewing position, which is the intermediate position, and the third slewing position, which is the forward position.

[0101] The control unit t receives an instruction for the second boom 413 to begin rotating from the intermediate position (second rotation position) and the forward position (third rotation position) toward the retracted position (first rotation position). If the control unit t determines that there is no change in the detection signal of the first switch Sw1 within a set elapsed time after the second boom 413 begins rotating, it determines that an abnormal condition exists and stops the operation of the second boom 413.

[0102] In this embodiment of the invention, in addition to the first boom 411 and the second boom 413, there are further multiple movable parts, If the control unit determines that the abnormal condition is present, it stops the operation of all of the multiple movable parts.

[0103] In this embodiment of the invention, in addition to the first boom 411 and the second boom 413, there are further multiple movable parts. If the control unit determines that the state is normal, it permits the continuation of the operation of the multiple movable parts.

[0104] (2) Next, we will explain another scenario in which there is a problem recognizing the first turning position, which is the reversing position shown in Figure 4. In the above-mentioned configuration, we assume a case where the control unit t cannot correctly recognize the first slewing position, which is the retracted position determined by the first switch Sw1, due to a break in the circuit from the first switch Sw1 to the control unit t, an internal malfunction of the first switch Sw1, or a physical abnormality of the second boom 413.

[0105] If the first boom 411 is rotated from the deployed position to the stowed position while the first rotation position, which is the retracted position of the second boom 413, is not correctly recognized, the first boom 411 may come into abnormal proximity to or come into contact with the traveling machine located in front of the main frame 11 because it is positioned in front of both the second boom 413 and the first boom 411. For example, as shown in Figure 3, if the control unit t mistakenly identifies the first boom 411 as being in the first rotation position 51-1, which is located to the rear, even though the second boom 413 is in the third rotation position 51-3, which is the position where it has rotated forward, the above-mentioned problem may occur.

[0106] Furthermore, even if the first boom 411 is initially in the retracted position (first slewing position), the above-mentioned problems may occur if the control unit t misinterprets the retracted position (first slewing position) as indicated by the first switch Sw1 while the first boom 411 is being retracted. For example, if the second boom 413 unexpectedly moves from the retracted position (first slewing position) while the first boom 411 is being retracted, the control unit t may not recognize this correctly, potentially causing other movable parts, including the second boom 413, to perform unintended actions.

[0107] The solution to the above problem will be explained. In order to resolve the above-mentioned inconveniences, the present invention controls the first boom 411 and the second boom 413 using the following control method. First, when the second boom 413 is in the first slewing position, which is the retracted position, and the control unit u receives an operation command to move the first boom 411 toward the stowed position, the control unit t starts the control flow shown in the flowchart Figure 12.

[0108] In Figure 12, at S21, when the control unit t receives a command for the first boom 411 to move toward the stowed position, it activates a timer (which will also be called the second timer). This timer measures the elapsed time, which is the set remaining time. In this embodiment, it is set to 2 seconds. The elapsed time measured by the timer can be freely changed depending on the specifications and capabilities of the work machine.

[0109] In S22, after this timer is activated, the second boom 413 is rotated toward the forward position, which is the third rotation position.

[0110] In S23, the control unit t then determines whether the first switch Sw1 has been released from being pressed by the first working part of the second boom 413 within the time elapsed since the second boom 413 began to rotate, as described above. In other words, the control unit t determines whether it has received a change in the detection signal due to the first switch Sw1 changing from a released state to a pressed state. If the second boom 413 has rotated to a position other than the first rotation position which is the retracted position, the detection signal of the first switch Sw1 changes from a released state to a pressed state, so the control unit t determines whether or not there has been a change in the detection signal.

[0111] In S24, if the control unit determines that there has been a change in the detection signal within the elapsed time, it restarts the timer (which may also be called the third timer). This timer measures the elapsed time, which is the set remaining time. In this embodiment, the timer time after the detection signal is determined is set to 2 seconds, as described above. The elapsed time, which is the timer, can be freely changed depending on the specifications and capabilities of the work machine, and it can also be set to be different from the timer setting time immediately after the start of control.

[0112] In S25, after the third timer is activated, the second boom 413 is rotated toward the first slewing position, which is the retracted position. The slewing operation at this time is commanded to the directional control valve 25 to continue until the remaining time on the third timer reaches zero.

[0113] In S26, after operating the second boom 413 until the timer remaining time reaches 0, the control unit t processes the system as being in a normal state, with the switch (first switch Sw1) itself and the circuit from the control unit t to the switch (first switch Sw1) being normal, the second boom 413 itself including the first operating part being normal, and the components that drive the second boom 413 (cylinder, directional control valve, pumps, etc.) being normal.

[0114] The determination of a normal state involves setting a flag that signals permission for the operation of multiple other movable parts, including the second boom 413 in the next process, and then terminating the process. This determination enables other control functions.

[0115] After determining that there has been a change in the detection signal, the control unit t further rotates the second boom 413 toward the first slewing position, which is the retracted position, and then determines that it is in a normal state. In other words, after restoring the position of the second boom 413 to the first slewing position, which is the retracted position at the start of operation, it sets the operation permission flag for the next step. In this embodiment, the next step is to move the first boom 411 toward the stowed position. In this way, the first boom 411 can be moved toward the stowed position while the second boom 413 is in the first slewing position, which is the retracted position.

[0116] In this embodiment of the invention, in S27, instead of generating a flag before the second boom 413 returns to the first slewing position which is the retracted position, the operation permission flag for the next process is generated after the second boom 413 returns to the first slewing position which is the retracted position. This prevents the setting of the operation permission flag for the next process with a simple configuration, even considering the case where the operator releases the operation of the control unit u before the second boom 413 returns to the first slewing position which is the retracted position.

[0117] Then, the next operation, which involves rotating the first boom 411 toward the stowed position, can be performed while the second boom 413 is in the first rotation position, which is the retracted position.

[0118] In S28, if the control unit t determines in S23 that there was no change in the detection signal within the timer elapsed time, the switch (first switch Sw1) itself and the circuit from the control unit t to the switch (first switch Sw1) are processed as abnormal, the second boom 413 including the first operating part is processed as abnormal, and the components that drive the second boom 413 (cylinder, directional control valve, pumps, etc.) are processed as being in an abnormal state. An abnormal flag is generated based on the determination of the abnormal state.

[0119] In response to this flag signal, in S29, the control unit t commands the operation of the second boom 413 to stop and issue a warning signal. Furthermore, since this embodiment has several other movable parts in addition to the operation of the second boom 413, the control unit also issues prohibition commands to stop the operation of these other movable parts and make their operation impossible, thereby terminating the process.

[0120] With the above control method, when the second boom 413 moves the first boom 411 from the first slewing position, which is the retracted position stored in the control unit t, toward the stowed position, the second boom 413 is first moved toward the second slewing position, which is the intermediate position in the forward direction, before moving the first boom 411 toward the stowed position, to check the integrity of the first switch Sw1. If there is an abnormality, all movable parts are immediately stopped, and if it is normal, the second boom 413 is returned to the first slewing position, which is the retracted position, and then a flag indicating a normal state is generated. At the point when the flag indicating a normal state is generated, the second boom 413 is definitely in the first slewing position, which is the retracted position, so even if the first boom 411 is moved toward the stowed position, the second boom 413 and the working section 51 at the tip of the second boom 413 will not come abnormally close to the traveling machine located in the forward direction.

[0121] By operating the second boom 413 for a specified time, the integrity of the first switch Sw1 can be clearly confirmed. This ensures that at least the integrity of the first switch Sw1, which determines the position of the second boom 413, is ensured. Furthermore, the integrity of the second boom 413 and its drive mechanism, which press the first switch Sw1, can also be verified.

[0122] By simplifying the mechanism for determining the position of the second boom 413, the load on these calculation processes is reduced, while also making it easier for operators to identify the faulty part when an abnormality occurs. This allows for a reduction in the time required for repairs.

[0123] Furthermore, if an abnormal condition is detected, the system is designed to stop the operation of all movable parts, thereby preventing unintentional operation of all movable parts, including the first boom 411 and the second boom 413, which could lead to abnormal proximity to or contact with the mobile body or other components.

[0124] This control allows the control unit t to confirm the integrity of at least the first switch Sw1 when rotating the first boom 411 to the stowed position, starting from a state where the second boom 413 is stored in the first slewing position (retracted position) before the control unit starts. Furthermore, it can also be said that the integrity of the second boom 413 and the drive mechanism that operates it can also be confirmed. Therefore, when moving the first boom 411 to the stowed position, it is possible to ensure that the first switch Sw1 is operating reliably and that the second boom 413 is in the first slewing position (retracted position), thereby preventing malfunctions due to a failure of the first switch Sw1.

[0125] The operation of the second boom 413 described in the embodiment of this invention applies not only when the second boom 413 is operated independently by the operating lever u3, but also when it is operated automatically by a button that automatically operates all movable parts. In other words, it applies to all operations in which the second boom 413 rotates from a location other than the first rotation position (retracted position) toward the first rotation position (retracted position).

[0126] Furthermore, the control operation of the present invention is designed to be canceled if the operation by the control unit u is released during the control operation.

[0127] In the embodiment of the present invention, when the control unit t fails to correctly recognize the change in the detection signal of the first switch Sw1 during the operation of the second boom 413, it is possible to prevent a situation in which the boom comes into close proximity to the traveling machine, especially when it is operated towards the stowed position.

[0128] The modified examples will be explained based on the flowchart in Figure 13. As shown in Figure 13, a point can be added in S36 to determine whether or not there is a change in the detected signal. As described in the above embodiment, the second boom 413 is first moved to the intermediate position, the second slewing position, and after it is determined that there has been a change in the detection signal, it is moved back to the retracted position, the first slewing position. In the modified example shown in the flowchart Figure 13, points are added in S35 and S36 to determine whether there has been a change in the detection signal of the first switch Sw1 after the second boom 413 has returned to the retracted position, the first slewing position, within a specified time. In other words, the control unit t recognizes a normal state and generates a flag only when it determines that there has been a change in the detection signal of the first switch Sw1 both when the second boom 413 moves to the forward path and when it moves to the return path. If there is an abnormality in either the forward or return path of the second boom 413, it is considered an abnormal state and a flag is generated.

[0129] In other words, in S31, when the control unit t receives a command for the first boom 411 to move toward the stowed position, it activates a timer (let's call it the second timer). This timer measures the elapsed time, which is the set remaining time. In this embodiment, it is set to 2 seconds. The elapsed time of the timer can be freely changed depending on the specifications and capabilities of the work machine.

[0130] In S32, after this timer is activated, the second boom 413 is rotated toward the forward position, which is the third rotation position.

[0131] In S33, the control unit t then determines whether the first switch Sw1 has been released from being pressed by the first operating part of the second boom 413 within the time elapsed since the second boom 413 began to rotate, as described above. In other words, the control unit t determines whether it has received a change in the detection signal due to the first switch Sw1 changing from a released state to a pressed state. If the second boom 413 has rotated to a position other than the first rotation position which is the retracted position, the detection signal of the first switch Sw1 changes from a released state to a pressed state, so the control unit t determines whether or not there has been a change in the detection signal.

[0132] In S34, if the control unit determines that there has been a change in the detection signal within the elapsed time, it restarts the timer (which may also be called the third timer). This timer measures the elapsed time, which is the set remaining time. In this embodiment, the timer time after the detection signal is determined is set to 2 seconds, as described above. The elapsed time, which is the timer, can be freely changed depending on the specifications and capabilities of the work machine, and it can also be set to be different from the timer setting time immediately after the start of control.

[0133] In S35, after the third timer is activated, the second boom 413 is rotated toward the first slewing position, which is the retracted position. The directional control valve is instructed to perform this rotation until the remaining time on the third timer reaches zero.

[0134] In S36, the second boom 413 returns to the first slewing position, which is the retracted position, within the specified time, and it is determined whether there has been a change in the detection signal of the first switch Sw1.

[0135] In S37, after operating the second boom 413 until the timer remaining time reaches 0, the control unit t processes the system as being in a normal state, with the switch (first switch Sw1) itself and the circuit from the control unit t to the switch (first switch Sw1) being normal, the second boom 413 itself including the first operating part being normal, and the components that drive the second boom 413 (cylinder, directional control valve, pumps, etc.) being normal.

[0136] The determination of a normal state involves setting a flag that signals permission for the operation of multiple other movable parts, including the second boom 413 in the next process, and then terminating the process. This determination enables other control functions.

[0137] After determining that there has been a change in the detection signal, the control unit t further rotates the second boom 413 toward the first slewing position, which is the retracted position, and then determines that it is in a normal state. In other words, after restoring the position of the second boom 413 to the first slewing position, which is the retracted position at the start of operation, it sets the operation permission flag for the next step. In this embodiment, the next step is to move the first boom 411 toward the stowed position. In this way, the first boom 411 can be moved toward the stowed position while the second boom 413 is in the first slewing position, which is the retracted position.

[0138] In S38, in the embodiment, instead of generating a flag before the second boom 413 returns to the first slewing position which is the retracted position, the operation permission flag for the next process is generated after the second boom 413 returns to the first slewing position which is the retracted position. This prevents the operation permission flag for the next process from being set with a simple configuration, even if the operator releases the operation of the control unit u before the second boom 413 returns to the first slewing position which is the retracted position.

[0139] Then, the next operation, which involves rotating the first boom 411 toward the stowed position, can be performed while the second boom 413 is in the first rotation position, which is the retracted position.

[0140] In S39, if the control unit t determines that there has been no change in the detection signal within the timer elapsed time, it processes the switch (first switch Sw1) itself and the circuit reaching the switch (first switch Sw1) from the control unit t as abnormal, the second boom 413 including the first operating part as abnormal, and the components that drive the second boom 413 (cylinder, directional control valve, pumps, etc.) as being in an abnormal state. An abnormal flag is generated based on the determination of the abnormal state.

[0141] In response to this flag signal, in S40, the control unit commands the second boom 413 to stop its operation and to emit a warning signal. Furthermore, since this embodiment has several other movable parts in addition to the second boom 413, the control unit also issues prohibition commands to stop the operation of these other movable parts and to make their operation impossible, thereby terminating the process.

[0142] With the above control method, when the second boom 413 moves the first boom 411 from the first slewing position, which is the retracted position stored in the control unit t, toward the stowed position, the second boom 413 is first moved toward the second slewing position, which is the intermediate position in the forward direction, before moving the first boom 411 toward the stowed position, to check the integrity of the first switch Sw1. If there is an abnormality, all movable parts are immediately stopped, and if it is normal, the second boom 413 is returned to the first slewing position, which is the retracted position, and then a flag indicating a normal state is generated. At the point when the flag indicating a normal state is generated, the second boom 413 is definitely in the first slewing position, which is the retracted position, so even if the first boom 411 is moved toward the stowed position, the second boom 413 and the working section 51 at the tip of the second boom 413 will not come abnormally close to the traveling machine located in the forward direction.

[0143] By operating the second boom 413 for a specified time, the integrity of the first switch Sw1 can be clearly confirmed. This ensures that at least the integrity of the first switch Sw1, which determines the position of the second boom 413, is ensured. Furthermore, the integrity of the second boom 413 and its drive mechanism, which press the first switch Sw1, can also be verified.

[0144] By simplifying the mechanism for determining the position of the second boom 413, the load on these calculation processes is reduced, while also making it easier for operators to identify the faulty part when an abnormality occurs. This allows for a reduction in the time required for repairs.

[0145] Furthermore, if an abnormal condition is detected, the system is designed to stop the operation of all movable parts, thereby preventing unintentional operation of all movable parts, including the first boom 411 and the second boom 413, which could lead to abnormal proximity to or contact with the mobile body or other components.

[0146] This control allows the control unit t to confirm the integrity of at least the first switch Sw1 when rotating the first boom 411 to the stowed position, starting from a state where the second boom 413 is stored in the first slewing position (retracted position) before the control unit starts. Furthermore, it can also be said that the integrity of the second boom 413 and the drive mechanism that operates it can also be confirmed. Therefore, when moving the first boom 411 to the stowed position, it is possible to ensure that the first switch Sw1 is operating reliably and that the second boom 413 is in the first slewing position (retracted position), thereby preventing malfunctions due to a failure of the first switch Sw1.

[0147] The operation of the second boom 413 described in the embodiment applies not only when the second boom 413 is operated independently by the operating lever u3, but also when it is operated automatically by pressing a button on the operating unit u that automatically operates all movable parts. In other words, it applies to all operations in which the second boom 413 rotates from a location other than the first rotation position (retracted position) toward the first rotation position (retracted position).

[0148] Furthermore, the control operation of the present invention is designed to be canceled if the operation by the control unit u is released during the control operation.

[0149] The present invention makes it possible to prevent situations in which the second boom 413 comes into close proximity to the traveling machine when the control unit t fails to correctly recognize the change in the detection signal of the first switch Sw1 during the operation of the second boom 413, and especially when the second boom 413 is moved from a position stored as being in the first slewing position (retracted position) toward the stowed position.

[0150] In addition, by controlling the modification, the integrity of the first switch Sw1 can be confirmed more reliably, and the integrity of the second boom 413 and the drive mechanism that operates it can also be confirmed more reliably.

[0151] Therefore, in the embodiments of this invention, A first boom 411 that can rotate relative to the main frame between the deployed position and the stowed position, A second boom 413 is provided to be rotatable so as to be positioned at a first slewing position which is a retracted position relative to the first boom 411, a second slewing position which is an intermediate position, and a third slewing position which is an advanced position, A first switch Sw1 detects the second slewing position, which is the intermediate position of the second boom 413, and emits a detection signal. The system includes a control unit t connected to the first switch Sw1, which is capable of recognizing a first slewing position, which is the retracted position of the second boom 413, and a second slewing position, which is an intermediate position,

[0152] The control unit t is characterized in that, when the second boom 413 is in the first slewing position, which is the retracted position, and the first boom 411 is instructed to slewing toward the storage position, the control unit t slewing the second boom 413 toward the second slewing position, which is the intermediate position, and if the detection signal from the first switch Sw1 does not change, it determines that the first switch is in an abnormal state and stops the operation of the first boom 411.

[0153] Furthermore, in the embodiments of this invention, When the control unit t receives an instruction to rotate the first boom 411 toward the storage position while the second boom 413 is in the first storage position, it rotates the second boom 413 toward the intermediate position, the second rotation position, and when the detection signal from the first sensor first switch Sw1 changes, it rotates the second boom 413 toward the retracted position, the first rotation position, and when the detection signal from the first switch Sw1 changes again, it determines that the first switch is in a normal state.

[0154] Furthermore, in the embodiments of this invention, After the control unit t determines that the first switch is in a normal state, it rotates the first boom 411 toward the stowed position.

[0155] Furthermore, in the embodiments of this invention, In addition to the first boom 411 and the second boom 413, the system has a further number of movable parts, and when the control unit determines that the first switch is in an abnormal state, it stops the operation of all of the multiple movable parts.

[0156] Furthermore, in the embodiments of this invention, In addition to the first boom 411 and the second boom 413, it has several more movable parts, When the control unit t determines that the first switch is in an abnormal state, it stops the operation of all of the multiple movable parts. When the control unit determines that the state is normal, it permits the continuation of the operation of all of the multiple movable parts. The present invention makes it possible to prevent situations in which the second boom 413 comes into close proximity to the traveling machine when the control unit t fails to correctly recognize the change in the detection signal of the first switch Sw1 during operation, particularly when the switch is operated to the stowed position. [Explanation of Symbols]

[0157] 11 Main Frame 111 Mounting part (lower) 112 Mounting part (top) 21 Mast Frame 24. Fluid pressure source (hydraulic pump) 31. Tank (oil tank) 41 Expanding means 411 First Boom 411A First pivot axis (horizontal axis) 412 1st connector 413 Second Boom 414 Second Connector 415 First Cylinder 416 Second Cylinder 417 Third Cylinder 418 Fourth Cylinder 42 Link mechanism 51 Work Unit 512 Rotation axis A work machine t Control section u Operation section u3 Operating lever SE1 First Sensor Se2 Second Sensor Sw1 1st Switch Sw2 2nd Switch

Claims

1. A first boom that is rotatable, The system includes a second boom that is rotatable relative to the first boom in a direction intersecting the rotation direction of the first boom, and which is positioned to be in a first rotation position which is a retracted position relative to the first boom, a second rotation position which is an intermediate position, and a third rotation position which is an advanced position, depending on the rotation angle. A first switch for detecting the second slewing position, which is the intermediate position of the second boom, A second switch for detecting the third slewing position, which is the forward position of the second boom, The system includes a control unit connected to the first switch and the second switch, which can recognize the first slewing position (the retracted position), the second slewing position (the intermediate position), and the third slewing position (the forward position) of the second boom by receiving detection signals from the first switch and the second switch, The control unit, upon receiving an instruction for the second boom to begin rotating from the second rotation position (intermediate position) and the third rotation position (advancing position) toward the first rotation position (retracted position), determines that there is no change in the detection signal of the first switch within a set elapsed time after the second boom begins rotating, and determines that an abnormal condition exists, and stops the operation of the second boom. A work machine characterized by the following features.

2. In addition to the first boom and the second boom, it has a further number of movable parts, When the control unit determines that the abnormal condition is present, it stops the operation of all of the multiple movable parts. The work machine according to feature 1.

3. In addition to the first boom and the second boom, it has a further number of movable parts, When the control unit determines that the state is normal, it permits the continuation of the operation of the plurality of movable parts. The work machine according to feature 1.

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