Hydraulic excavator

A hydraulic excavator includes a cab and a work implement arranged on one lateral side of the cab. The cab includes an operator's seat, front pillars, a roof portion, first and second guide rails, a front window, a monitor device, a monitor, and a support member. The monitor is supported on a first pillar above the monitor device and has a second display screen larger than a first display screen. The support member supports the monitor so as to be movable between an interference position interfering with a movement region where the front window moves between a closed state and an opened state of an opening, and a non-interference position with no interference. Accordingly, a hydraulic excavator can be obtained in which a large-sized monitor can be arranged on a front side of the cab without interference with a movable front window.

TECHNICAL FIELD

The present invention relates to a hydraulic excavator, and more particularly to a hydraulic excavator employing an information-oriented construction system.

BACKGROUND ART

In recent years, introduction of information-oriented construction to a work vehicle is rapidly promoted. The information-oriented construction is a system for the purpose of achieving construction with high efficiency and high accuracy in a construction stage of a construction project by conducting position detection for a work implement with use of an information and communication technology (ICT) and automatically controlling the work implement based on the detected position of the work implement. A conventional work vehicle employing the information-oriented construction system is disclosed for instance in PTD 1 (Japanese Patent Laying-Open No. 2005-163470).

CITATION LIST

Patent Document

SUMMARY OF INVENTION

Technical Problem

Since the amount of information to be displayed on a monitor for the information-oriented construction is large, a monitor conventionally provided in a cab cannot display information sufficiently. Therefore, enlargement of a monitor is required. Further, the monitor for the information-oriented construction is arranged at a location where the monitor can be seen readily during operation, for example, on the front side in the cab. On the other hand, it is required that a front window on the front side of the cab is provided openably and closably so that an operator can visually recognize the work implement. If the monitor is simply enlarged, there may be a case where the front window cannot be opened due to interference between the monitor and the front window when opening the front window.

The present invention was made in view of the problem described above, and its object is to provide a hydraulic excavator in which a monitor with a large-sized screen can be arranged on the front side of the cab without interference with a movable front window.

Solution to Problem

A hydraulic excavator of the present invention is a hydraulic excavator including a cab and a work implement arranged on one lateral side of the cab. The cab includes an operator's seat, front pillars, a roof portion, a first guide rail, a second guide rail, a front window, a first monitor, a second monitor, and a support member. The front pillars are arranged in front of the operator's seat. The front pillars have a first pillar arranged on one lateral side and a second pillar arranged on the other lateral side. The roof portion covers above the operator's seat. The first guide rail extends along the first and second pillars respectively. The second guide rail extends along the roof portion. The front window has an upper end portion and a lower end portion. The upper end portion is movable along the second guide rail, and the lower end portion is movable along the first guide rail. The first monitor is arranged on a side of the first pillar in front of the operator's seat, and has a first display screen. The second monitor is supported on the first pillar above the first monitor and has a second display screen larger than the first display screen. The support member has a base portion fixed to the first pillar, a rotating unit supported on the base portion rotatably, and a universal joint supporting the second monitor on the rotating unit. The support member supports the second monitor so as to be movable to an interference position interfering with a moving region where the front window moves between a closed state and an opened state of an opening formed between the first and second pillars, and a non-interference position with no interference.

According to the hydraulic excavator of the present invention, the second monitor having the second display screen larger than the first display screen is provided. Therefore, information for the information-oriented construction can be displayed sufficiently. Further, when moving the front window, interference between the second monitor having a large display screen and the front window can be avoided by moving the second monitor to the non-interference position. Further, among the front pillars arranged on the front side in the cab, the second monitor can be mounted through the support member to the first pillar provided on a side close to the work implement. Therefore, a vision shift amount of an operator during operation of the work implement can be made small, so that the work efficiency can be improved. Further, by rotating the second monitor relative to the support member to allow rotation of the support member relative to the first pillar, the second monitor can be moved relative to the first pillar. Thus, the second monitor can be moved readily from the interference position to the non-interference position.

In the hydraulic excavator described above, the second display screen has an upper edge and a lower edge. When the second monitor is at the interference position, the upper edge is arranged more on the front side than the lower edge. When the second monitor is at the non-interference position, the lower edge is arranged more on the front side than the upper edge.

Accordingly, visibility of the second display screen can be improved when an operator is seated on the operator's seat, so that the operator can see the second display screen more readily.

In the hydraulic excavator described above, when the second monitor is at the non-interference position, the second display screen is oriented toward the lateral side of the cab more than the state where the second monitor is at the interference position.

In such a manner, the second monitor can be moved from the interference position to the non-interference position by moving the second monitor so as to allow the second display screen to be oriented toward the lateral side of the cab.

In the hydraulic excavator described above, the cab further includes a control lever. The control lever at a neutral position is arranged to avoid interference with the most rear part of the second monitor. The control lever is arranged to avoid interference with the most rear part of the second monitor as long as it is at a neutral position regardless of the position of the control lever in the forward and backward directions.

Accordingly, interference between the second monitor and the control lever can be avoided reliably when the second monitor is moved to the non-interference position to avoid interference between the front window and the second monitor.

Advantageous Effects of Invention

As described above, according to the present invention, a second monitor with a large-sized screen can be arranged on a front side in a cab without interference with a front window movable between a closed position and an opened position.

DESCRIPTION OF EMBODIMENTS

First Embodiment

Firstly, a configuration of a hydraulic excavator to which the idea of the present invention is applicable will be described.

Referring toFIG. 1, a hydraulic excavator1mainly includes a lower traveling unit2, an upper revolving unit3, and a work implement5. Lower traveling unit2and upper revolving unit3constitute a work vehicle main body.

Lower traveling unit2has a pair of left and right crawler belts. It is configured to allow hydraulic excavator1to be self-propelled by rotation of the pair of crawler belts. Upper revolving unit3is revolvably mounted on lower traveling unit2.

Upper revolving unit3includes a cab4, which is a compartment for an operator to operate hydraulic excavator1, at a left side L on a front side F (vehicle front side). Cab4is included in the work vehicle main body. Upper revolving unit3includes an engine compartment for accommodating an engine and a counter weight on a rear side B (vehicle rear side). In the present embodiment, when an operator is seated in cab4, the leftward direction from the operator will be referred to as left side L, the rightward direction as a right side R, the forward direction as front side F, and the backward direction as a rear side B.

Work implement5for performing operation such as earth excavation is pivotally supported by upper revolving unit3so as to be swingable in the upward and downward directions. Work implement5has a boom6mounted swingably in the upward and downward directions at a substantially central portion on front side F of upper revolving unit3, an arm7mounted swingably in the forward and backward directions at a leading end portion of boom6, and a bucket8mounted swingably in the forward and backward directions at a leading end portion of arm7. Boom6, arm7, and bucket8are configured to be swingably driven respectively by a boom cylinder9, an arm cylinder10, and a bucket cylinder11, which are hydraulic cylinders.

Work implement5is provided on right side R relative to cab4. Work implement5is provided on right side R as one lateral side of cab4relative to cab4arranged at left side L on front side F of upper revolving unit3. It should be noted that arrangement of cab4and work implement5is not limited to the example shown inFIG. 1. For example, work implement5may be provided on the left side of cab4arranged on the front right side of upper revolving unit3.

Referring toFIG. 2, a PTO (abbreviation of Power Take Off) device29of an engine25mounted on rear side B of upper revolving unit3is coupled with a plurality of hydraulic pumps31a,31b,32a,32b,33a,33b,34. Hydraulic pump34supplies a pilot pressure to a pilot pressure operation valve12operated with control lever13. Other hydraulic pumps31a-33bsupply pressurized oil to each of hydraulic cylinders9,10, and11for actuating work implement5, a revolving motor for revolvably driving upper revolving unit3, left and right travel motors37a,37bprovided in lower traveling unit2, and the like. The hydraulic circuit for driving the actuator not illustrated inFIG. 2is configured by a circuit similar to the circuit illustrated inFIG. 2.

The pressurized oil discharged from hydraulic pumps31a,31bis supplied to right travel motor37b, boom cylinder9, bucket cylinder11, and arm cylinder10respectively through a right travel motor switching valve14a, a boom switching valve14b, a bucket switching valve14c, and an arm switching valve14d. Pilot operation portions of these switching valves14a-14dreceive supply of corresponding pilot pressure from pilot pressure operation valve12.

Discharge tube passages of hydraulic pumps31a,31b, discharge tube passages of hydraulic pumps32a,32b, and discharge tube passages of hydraulic pumps33a,33bare provided with pressure sensors35a,35b,36for detecting respective pump discharge pressure. The tube passages connecting switching valves14a-14dand each actuator are provided with pressure sensors16a,16b,17a,17b,18a,18b,19a,19bfor detecting a load pressure of each actuator, respectively. Also with regard to the revolving motor and left travel motor37a, connection passages thereof are similarly provided with pressure sensors (not illustrated) for detecting respective load pressures. Detection signals of these pressure sensors are inputted to controller20. Controller20calculates load frequencies (occurrence frequency for each load level, and corresponding to a load amount) for the work implement and the travel driver of lower traveling unit2respectively based on load pressure detection values of actuators from the pressure sensors.

Fuel injection pump26of engine25receives input of a fuel injection amount instruction from engine controller22. Engine controller22receives input of a detection signal of an engine rotation speed sensor27provided on an output rotating shaft of engine25as a feedback signal. Engine controller22calculates fuel injection amount instruction so as to drive engine25with a predetermined horse power based on the feedback signal of the engine rotation speed and outputs the same, and inputs the engine rotation speed and the outputted fuel injection amount instruction to controller20.

Controller20, engine controller22, and monitor21are connected through a bidirectional communication cable23to form a communication network in hydraulic excavator1. Monitor21, controller20, and engine controller22are capable of transmitting information with each other via network communication cables23,23. It should be noted that monitor21, controller20, and engine controller22are respectively configured to have computer devices such as microcomputers as main bodies.

Information can be transmitted between controller20and an outside monitoring station76. In the present embodiment, controller20and monitoring station76communicate with each other through a satellite communication. Controller20is connected with a communication terminal71having a satellite communication antenna72. As shown inFIG. 1, satellite communication antenna72is mounted to upper revolving unit3. Monitoring station76on the earth is connected via the internet with a network control station75, which is coupled via a dedicated line with a communication earth station74communicating with communication satellite73via a dedicated communication line. Accordingly, data is transmitted between controller20and predetermined monitoring station76via communication terminal71, communication satellite73, communication earth station74, and network control station75.

An example of mounting the information-oriented construction system to hydraulic excavator1of the present embodiment will be described. The construction design data created by three-dimensional CAD (Computer Aided Design) is stored in advance in controller20. Monitor21displays real-time updates of current position of hydraulic excavator1on a screen, so that an operator can always confirm the working condition of hydraulic excavator1.

Controller20compares construction design data with a position and a posture of work implement5in real-time manner, and drives the hydraulic circuit based on the result of comparison to control work implement5. More specifically, a position at which construction should be conducted in accordance with the construction design data and a position of bucket8are matched to perform construction such as excavation, ground leveling, or the like thereafter. Accordingly, since work implement5of hydraulic excavator1is automatically controlled based on the construction design data, there is no need to provide a stake as a mark during construction, so that construction efficiency is improved. Additionally, construction accuracy can be improved, so that high-quality construction practice can be readily performed.

Referring back toFIGS. 1 and 3, an operator's seat61to be seated by an operator oriented toward front side F is arranged inside cab4. Cab4includes a roof portion arranged to cover operator's seat61, and a plurality of pillars supporting the roof portion. The plurality of pillars have front pillars40arranged on front side F relative to operator's seat61, rear pillars46arranged on rear side B relative to operator's seat61, and an intermediate pillar44arranged between front pillars40and rear pillars46. Each pillar extends in the vertical direction orthogonal to a horizontal plane, and is coupled to a floor portion and a roof portion of cab4.

Front pillar40has a first pillar41and a second pillar42. Work implement5is arranged on right side R relative to cab4, and first pillar41is arranged on right side R (one lateral side) which is a side close to work implement5. Second pillar42is arranged on left side L (the other lateral side) which is away from work implement5. A space surrounded by first pillar41, second pillar42, and a pair of rear pillars46forms a room space of cab4. Operator's seat61is accommodated in the room space of cab4, and is arranged at a substantially central portion of the floor portion of cab4. At a lateral face on left side L of cab4, a door for allowing an operator to board and exit cab4is provided.

A front window47is arranged between first pillar41and second pillar42. Front window47is arranged on front side F relative to operator's seat61. Front window47is formed of transparent material so that an operator seated on operator's seat61can visually recognize outside of cab4through front window47. For example, as shown inFIG. 3, the operator seated on operator's seat61can directly see bucket8excavating the earth through front window47.

Referring toFIG. 3, a monitor device66is provided on front side F in cab4. Monitor device66is arranged at the corner portion on the right front side in cab4and supported by a supporting stand extending from the floor portion of cab4. Monitor device66is arranged on the side of operator's seat61relative to first pillar41. Monitor device66is arranged on the near side of first pillar41when viewed from the operator seated on operator's seat61.

Since monitor device66is used for various purposes, it includes a planar display screen66dhaving various monitor functions, a switch portion67having a plurality of switches with various functions allotted, and a voice generator68vocally presenting the contents displayed on display screen66d. This display screen66dis configured by a graphic display such as a liquid crystal display, a plasma display, or the like. Switch portion67is constituted by a plurality of key switches, but not limited to it. It may be constituted by touch switches of a touch-panel type.

On front side F of operator's seat61, there are provided left and right travel control levers63a,63bas a traveling operation unit62for operating lower traveling unit2. On left side L and right side R of operator's seat61, there are provided work implement control levers64,65for operating actuation of work implement5(boom6, arm7, and bucket8) and revolving of upper revolving unit3, respectively. Left and right travel control levers63a,63band work implement control levers64,65correspond to control lever13shown inFIG. 2. These control levers are connected with respective pilot pressure operation valves12(refer toFIG. 2) for operating actuation of hydraulic cylinders9,10,11for work implement5, a revolving motor, and left and right travel motors37a,37b. On right side R of operator's seat61, there is also provided a console69for operating work implement5.

Above monitor device66, there is arranged monitor21described with reference toFIG. 2for displaying a current position of hydraulic excavator1received from outside. Monitor21has a planar display screen21d. Comparing display screen66dof monitor device66with display screen21dof monitor21shown inFIG. 3, display screen21dis provided so as to be larger than display screen66d. For example, monitor device66may have display screen66dof 7 inches, and monitor21may have display screen21dof 12 inches.

Among the pair of front pillars40, monitor21is attached to first pillar41on right side R close to work implement5and arranged on rear side B of first pillar41. Monitor21is arranged on the near side of first pillar41in the line of sight toward the right front side of the operator seated on operator's seat61. In hydraulic excavator1including work implement5on right side R of cab4, attaching monitor21to first pillar41allows the operator to see both work implement5and monitor21with a small vision shift amount.

Monitor21is attached to first pillar41through a support member50. Referring toFIGS. 4 and 5, a plate-like fin portion49is fixed on rear side B relative to first pillar41. Fin portion49is provided so as to be not movable relative to first pillar41. Fin portion49is arranged so as to extend in the forward and backward directions of cab4and has an inner surface oriented toward left side L and an outer surface oriented toward right side R. Support member50is attached to the inner side surface of fin portion49.

Support member50includes a base member attached to an inner side surface of fin portion49, a joint member52attached to a back side of monitor21, and arm members55,56provided between base member51and joint member52.

Base member51has a spherical sphere portion and a disk-like plate portion53. Plate portion53has a plurality of through holes531formed to penetrate through plate portion53in the thickness direction. Joining members532are provided to penetrate through through holes531, so that plate portion53is joined to fin portion49. Base member51is fixed to first pillar41through fin portion49. Fin portion49and base member51serve as a base portion fixed to first pillar41.

Joint member52has a spherical sphere portion and a disk-like plate portion54. Plate portion54has a plurality of though holes541formed to penetrate through plate portion54in the thickness direction. Joining members are provided to penetrate through through holes541, so that plate portion54is joined to monitor21. Joint member52serves as a supporting portion attached to monitor21.

Arm members55,56are arranged to sandwich the spherical portion of base member51on one end and the spherical portion of joint member52on the other end. Arm members55,56serve as a rotating unit. Joint member52serves as a universal joint. Arm member55has a threaded hole551, and arm member56has a through hole561. The pair of arm members55,56are joined together by a bolt member58penetrating through through hole561and screwed to threaded hole551. Bolt member58has a tab portion57on one end. An operator holds tab portion57and rotates the same to join and dismantle arm members55,56with use of bolt member58.

Arm members55,56are joined to fin portion49through the spherical portions of base member51, so that arm members55,56are provided to be movable relative to fin portion49by freely changing an angle relative to the inner surface of fin portion49. Accordingly, support member50is provided to be pivotable relative to first pillar41having fin portion49attached thereto.

Monitor21is joined to arm members55,56though the spherical portion of joint member52, so that monitor21is provided to be movable relative to arm members55,56by freely changing an angle relative to the extending direction of arm members55,56. Accordingly, monitor21is provided so as to be pivotable with respect to support member50.

By firmly tightening arm members55,56, the spherical portion of base member51is firmly sandwiched by arm members55,56, and the spherical portion of joint member52is firmly sandwiched by arm members55,56. Tightening by arm members55,56holds monitor21so as to be not movable with respect to first pillar41, so that monitor21can be positioned with respect to first pillar41.

By loosening tightened arm members55,56, support member50can be moved relative to fin portion49, so that monitor21can be moved relative to support member50. Accordingly, monitor21can be moved freely relative to first pillar41within a movable range determined by support member50.

Hereinafter, movement of monitor21inside cab4will be described in detail. Referring toFIGS. 6 and 7, cab4has a front wall141on front side F relative to operator's seat61, a rear wall144on rear side B, a roof portion142covering operator's seat61, and a floor portion143supporting operator's seat61from a lower side. Operator's seat61is arranged at a substantially central portion in the room space of cab4. Monitor device66is supported by a support stand69extending from floor portion143. Monitor21is attached to first pillar41through fin portion49and arranged above monitor device66.

In cab4, a first guide rail241extending along front wall141and a second guide rail242extending along roof portion142are arranged. First guide rail241extends along first and second pillars41,42respectively. Front window47is supported movably by first and second guide rails241,242. Front wall141has an opening141ashown inFIG. 7, and front window47is provided so as to be movable to a close position of closing said opening141aand an open position of opening said opening141a. Front window47is provided to be freely openable and closable. Front window47arranged at the closed position is supported by first guide rail241, and closes opening141aon front side F of cab4. Front window47moves upward to roof portion142of cab4from the close position, and then is arranged at the open position of opening said opening141a. Front window47arranged at the open position is supported by both first and second guide rails241,242.

FIG. 6shows arrangement of monitor21in the case where front window47is at the close position. Monitor21is arranged with display screen21doriented toward the side of operator's seat61so that the operator seated on operator's seat61can visually recognize display screen21din an easy manner.

FIG. 7illustrates a movement region of front window47moving between the close position and the open position. A grip471is attached to the surface of front window47on the side of the room space of cab4. Front window47is provided so as to be manually movable by an operator gripping grip471and lifting front window47. Front window7has an upper end portion and a lower end portion, and is provided so that the upper end portion is movable along roof portion142, and the lower end portion is movable along first and second pillars41,42.

ComparingFIGS. 6 and 7, if monitor21is kept arranged at the position shown inFIG. 6, monitor21interferes with the movement region of front window47. The position of monitor21shown inFIG. 6will be referred to as an interference position. If monitor21is at the interference position, movement of front window47is blocked, so that it becomes difficult for the operator to open front window47to directly see outside of cab4. Therefore, monitor21of the present embodiment is provided so as to be movable to a position of avoiding interference with the movement region of front window47. By moving monitor21from the interference position shown inFIG. 6to the position shown inFIG. 7, monitor21does not overlap with the movement region of front window47, so that monitor21does not interfere front window47. The position of monitor21shown inFIG. 7will be referred to as a non-interference position.

Referring toFIGS. 6-8, comparing monitor21arranged at the interference position (monitor21A) with monitor21arranged at the non-interference position (monitor21B), monitor21B is arranged at a position moved toward rear side B in cab4relative to monitor21A.

InFIG. 8, monitor21A at the interference position shown inFIG. 6is illustrated with a solid line, and monitor21B at the non-interference position shown inFIG. 7is illustrated with a two-dot chain line. Further, inFIG. 8, a straight line passing through a center of an upper edge21aand a center of a lower edge21bof rectangular-shaped display screen21dof monitor21is illustrated with a one-dot chain line as a center line CL. Further, inFIG. 8, a vertical direction V orthogonal to a horizontal plane is illustrated. A tilt angle at which center line CL of monitor21A at the interference position is tilted relative to vertical direction V is referred to as a first tilt angle θ1. A tilt angle at which center line CL of monitor21B arranged at the non-interference position is referred to as a second tilt angle θ2. In this instance, first tilt angle θ1is smaller than second tilt angle θ2. In other words, a tilt angle of monitor21B relative to vertical direction V is greater than that of monitor21A.

As to monitor21A at the interference position, upper edge21aof display screen21dis arranged more on front side F than lower edge21bof display screen21d. On the other hand, as to monitor21B at the non-interference position, upper edge21aof display screen21dis arranged more on rear side B than lower edge21bof display screen21d.FIGS. 6 and 7illustrate a cross section of cab4along the forward and backward directions. As shown inFIGS. 7 and 8, monitor21B is oriented toward the lateral side cab4more than monitor21A.

Console69shown inFIG. 3is arranged on right side R of operator's seat61. On the upper surface front side of console69, a work implement control lever65for actuating work implement5is provided. On the center and rear sides of the upper surface of console69, an arm rest is provided. Console69is configured so that a height and front/rear positions can be adjusted to readily operate levers, switches, and the like in accordance with a body shape of the operator seated on operator's seat61. Work implement control lever65is configured to be movable in forward/backward and leftward/rightward directions. Boom6of work implement5is lowered when work implement control lever65is moved forward, and is raised when work implement control lever65is moved backward. The bucket of work implement5is operated by leftward and rightward movement of work implement control lever65. In the state of not being operated, work implement control lever65is positioned at a neutral position at the center of forward/backward and leftward/rightward movement. At this neutral position, the work implement stops its operation.

Work implement control lever65shown inFIGS. 6 and 7is provided so as to be movable in the forward and backward directions by movement of console69.FIGS. 6 and 7represent the state where work implement control lever65is moved to most front side F and positioned at the neutral position in the forward and backward directions. As shown inFIG. 6, monitor21A at the interference position is arranged so as not to interfere with work implement control lever65in the state described above. As shown inFIG. 7, monitor21B at the non-interference position is arranged so as not to interfere with work implement control lever65in the state described above. Work implement control lever65, if it were at a neutral position, is arranged to avoid interference with monitor21whether it moves from the interference position to the non-interference position, regardless of the forward and backward position of console69, in other words, work implement control lever65.

Next, effect of the present embodiment will be described.

According to the present embodiment, in addition to monitor device66as a first monitor conventionally provided in cab4of hydraulic excavator1, monitor21as a second monitor is provided in cab4. Monitor21is a monitor for displaying real-time updates of a current position of hydraulic excavator1for the information-oriented construction, and the amount of information which should be displayed on display screen21dis large. Therefore, information for the information-oriented construction can be displayed sufficiently. By providing display screen21dof monitor21having a larger screen as compared to display screen66dof monitor device66, an operator can readily confirm information to be displayed on display screen21d.

Monitor21is supported by support member50so as to be movable to the interference position interfering with the movement region of front window47and the non-interference position of not interfering with the movement region of front window47. In the state where front window47is closed, monitor21can be arranged at the interference position so that an operator can readily confirm display screen21dof monitor21. On the other hand, when opening front window47, if monitor21is moved to the non-interference position, moving front window47does not interfere with monitor21, so that movement of front window47is not blocked by monitor21. Thus, a large-sized monitor21can be arranged on front side F of the internal space of cab4without interference with movable front window47.

Monitor21is attached to front pillar40on front side F relative the operator seated on operator's seat61. Particularly, monitor21is attached to the side on which work implement5is arranged relative to cab4, in other words, to first pillar41arranged on right side R. Since monitor21is arranged at a position overlapping with first pillar41from a view of an operator, a large-sized monitor21can be arranged in cab4without narrowing a sight of an operator during the construction. Since the operator can see both work implement5and monitor21with a small vision shift amount in the state of being seated on operator's seat61, confirmation of work becomes easier. Arranging support member50supporting monitor21at a position hidden behind monitor21from a view of the operator can preserve a wider sight of an operator.

Further, support member50is provided rotatably with respect to first pillar41, and monitor21is provided rotatably with respect to support member50. Accordingly, support member50is rotated relative to first pillar41while rotating monitor21with respect to support member50, so that monitor21can be moved relative to first pillar41. Therefore, a degree of freedom in arranging monitor21with respect to first pillar41is improved. Thus, monitor21can be moved more readily from the interference position to the non-interference position.

Arm members55,56of support member50are configured to be engaged and dismantled by the operator rotating tab portion57. Therefore, without need to use a tool, a position of monitor21can be adjusted by rotating tab portion57to loosen bolt member58. Monitor21can be detached from support member50by further loosening bolt member58. If monitor21is detachable, the operator can bring monitor21back after terminating the work.

As have been described with reference toFIG. 2, monitor21is connected to controller20through communication cable23, and supply of power and data communication with respect to monitor21are performed with use of communication cable23. If a connector enabling connection and disconnection of communication cable23is provided to allow detachment of connector at the time of detaching monitor21, communication cable23can be readily connected or detached. Surely, it is preferable to select a connector with high durability so that connection and detachment of the communication cable can be performed repeatedly.

Further, first tilt angle θ1at which monitor21at the interference position tilts relative to vertical direction V may be smaller than second tilt angle θ2at which monitor21at the non-interference position tilts relative to vertical direction V. Accordingly, monitor21is tilted with respect to vertical direction V, so that monitor21can be moved from the interference position to the non-interference position.

Further, when monitor21is at the interference position, upper edge21aof display screen21dis arranged more on front side F than lower edge21b. When monitor21is at the non-interference position, lower edge21bis arranged more on front side F than upper edge21a. Accordingly, an operator seated on operator's seat61can visually recognize display screen21din an easy manner.

Further, when monitor21is at the non-interference position, display screen21dmay be oriented toward the lateral side of cab4more as compared to the case of being at the interference position. Accordingly, monitor21can be moved so that display screen21dis oriented toward the lateral side of cab4to move monitor21from the interference position to the non-interference position.

Work implement control lever65may be arranged to avoid interference with the most rear part of monitor21at the neutral position. Accordingly, when monitor21is moved to the non-interference position to avoid the interference between front window47and monitor21, interference of monitor21with respect to work implement control lever65can be avoided.

Second Embodiment

Referring toFIG. 9, support member50of hydraulic excavator1according to the second embodiment has a configuration different from that of support member50according to the first embodiment shown inFIGS. 4 and 5in having a uniaxial hinge.

Support member50according to the second embodiment has a first arm portion351as a base portion fixed to first pillar41, a second arm portion352different from first arm portion351, and a hinge353coupling first arm portion351and second arm portion352. First arm portion351and second arm portion352are formed to have a shape of a rectangular plate. First arm portion351and second arm portion352are coupled so as to be relatively rotatable through hinge353. Therefore, second arm portion352is provided rotatably with respect to first arm portion351fixed to be not movable on first pillar41with a periphery of one end forming one side of the rectangle as an axis.

At the other end of second arm portion352forming other side of the rectangle, a joint member52is attached. Monitor21has a configuration such as a bracket to which the spherical portion of joint member52can be fitted. Monitor21is supported by support member50so as to be freely movable relative to second arm portion352about the spherical portion of joint member52as a center.

Support member50has a position retaining mechanism limiting relative movement between first arm portion351and second arm portion352. The position retaining mechanism is provided with a tab portion57. When an operator holds and rotates tab portion57, second arm portion352is switched to be rotatable or not rotatable relative to first arm portion351.

Also in the present embodiment, monitor21is supported by support member50so as to be movable to the interference position interfering with the movement region of front window47and the non-interference position of avoiding interference with the movement region of front window47. Specifically,FIG. 9shows monitor21at the interference position. From the state shown inFIG. 9, second arm portion352is rotated relative to first arm portion351to allow first arm portion351and second arm portion352are arranged so as to be on the same plane. Further, monitor21is rotated about the spherical portion of joint member52. Accordingly, monitor21can be moved to the non-interference position, so that the effect explained in the first embodiment can be obtained similarly.

Second arm portion352can be moved substantially only along the horizontal plane by connecting first arm portion351and second arm portion352by means of hinge353. Therefore, even in the case where insufficient fixing of second arm portion352by the position retaining mechanism occurs disadvantageously, lowering of the position of monitor21due to the own weight of monitor21can be prevented, so that the position of monitor21in vertical direction V can be made more stable.

In the embodiments 1 and 2 described above, the examples are described in which support member50has a universal joint which is a joint capable of freely changing angles of two joined members. Support member50is not limited to this configuration. For example, biaxial hinge type support member50having a hinge in place of joint member52shown inFIG. 9may be provided. Also in this case, appropriately designing the position and shape of the arm portion allows arrangement of both monitor21and support member50at positions not overlapping with the moving passage of front window47. In other words, as long as support member50is rotatable relative to first pillar41, and monitor21is rotatable relative to support member50, monitor21can be reliably moved from the interference position to the non-interference position by appropriately selecting support member50.

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