JP2006028798A - Construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction machine easy for an operator to handle by forbidding the operation of an actuator according to the positions of a driver's seat and a locking lever. <P>SOLUTION: A vehicle body is provided with the driver's seat turned in front and rear directions; a detecting switch 9 for detecting the position of the driver's seat; the locking lever 16 operated by the operator; and a detecting switch 17 for detecting the position of the locking lever 16. A pilot line 26 for operating the actuator is provided with a selector valve 29 held in a supply position (a) when the driver's seat 8 is in a seating position and the locking lever is in a lock release position. The driver's seat 8 in the front position is thereby prevented from coming in contact with levers 11-14 to operate a working device 5. Further, when the operator goes away from a vehicle, the working device 5 can be locked by the locking lever 16. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a construction machine such as a hydraulic excavator, and more particularly to a construction machine in which a driver's seat can be turned forward to perform a vehicle maintenance operation or the like.

  In general, there is a construction machine such as a hydraulic excavator configured such that, for example, various parts are arranged below the driver's seat, and the driver's seat is rotated to the front side when the parts are exchanged or inspected. (For example, refer to Patent Document 1).

Japanese Utility Model Publication No. 7-35563

  In this type of conventional hydraulic excavator, an upper swing body is rotatably mounted on a lower traveling body. The upper swing body is provided with a driver's seat on which the operator is seated and a plurality of operation levers that are positioned on the front side of the driver's seat and operated by the operator.

  Here, on the floor plate of the driver's seat, a driver's seat mount portion is provided at a position away from the operation lever on the rear side, and components such as electric components are disposed in the mount portion. The front side of the driver's seat is attached to the mount portion so as to be able to rotate forward and backward, and covers the driver seat from above while mounted on the mount portion. The driver seat mounting position is a normal position (sitting position) where the operator is seated when driving the hydraulic excavator.

  When the hydraulic excavator is operated, when the operator sits on the driver's seat and operates the front operation lever or the like, the pressure oil is supplied to and discharged from the hydraulic actuators in the various parts of the vehicle body according to the operation content. As a result, the operator can run the vehicle body, turn the upper swing body, and perform excavation work such as earth and sand by operating the working device.

  On the other hand, when exchanging parts in the mounting part of the driver's seat, performing inspection work, etc., the operator lifts the rear side with the front part of the driver's seat as a fulcrum, and pivots it forward to the operation lever side By doing so, the components in the mount portion are exposed.

  By the way, in the prior art mentioned above, when performing maintenance work etc. with respect to the components in a mount part, for example, it is set as the structure which rotates a driver's seat to the front side. However, an operation lever is arranged at a relatively close position on the front side of the driver's seat.

  For this reason, for example, when an operator performs a slight inspection during excavation work, when the driver's seat is rotated forward while the engine is running, the driver's seat comes into contact with the operation lever and the lever is pushed. In addition, there is a risk that the work device may perform an operation unintended by the operator, and this operation hinders the work.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to prevent the vehicle body and the work device from inadvertently operating even when the driver's seat comes into contact with the operation device. It is an object of the present invention to provide a construction machine that is easy to handle and can perform operations smoothly.

  In order to solve the above-described problems, the present invention comprises a self-propelled vehicle body and a working device provided on the vehicle body and operated by an actuator, and the vehicle body is normally held at a seating position where an operator is seated. The present invention is applied to a construction machine provided with a driver's seat that can be rotated forward from the seating position.

  The feature of the configuration adopted by the invention of claim 1 is that the vehicle body has a seat position detecting means for detecting whether or not the driver's seat is in the seating position, and a position between the locked position and the unlocked position by the operator. The actuator is allowed to operate when the lock lever that is switched in step S3 and the seat position detecting means detects that the driver's seat is in the seating position and the lock lever is in the unlocked position. And an operation prohibiting means for prohibiting the operation of the apparatus.

  According to the invention of claim 2, the lock lever is provided with lever position detecting means for detecting whether or not the lock lever is in the unlocked position, and the operation prohibiting means is detected by the seat position detecting means and the lever position detecting means. The operation of the actuator is permitted or prohibited according to the condition.

  According to a third aspect of the invention, the operation prohibiting means is constituted by a switching valve that supplies pressure oil to the actuator from a hydraulic source of the vehicle body or shuts off the supply.

  Further, according to the invention of claim 4, the operation prohibiting means is constituted by an electromagnetic pilot type switching valve for supplying pressure oil to the actuator from the hydraulic source of the vehicle body or shutting off the supply in accordance with the energized state of the solenoid portion. Between the power source and the ground, a seat position detecting means, a lever position detecting means and an electromagnetic pilot type solenoid unit are connected in series.

  According to the invention of claim 1, when the operator moves the driver's seat to the front side during the operation of the construction machine, this can be detected by the seat position detecting means, and the operation prohibiting means does not depend on the operator's attention or the like. The operation of the actuator can be automatically prohibited. For this reason, even if the driver's seat accidentally contacts the operating device, it is possible to reliably prevent the working device from performing an operation not intended by the operator, and various operations can be smoothly performed in this state. Further, when the operator returns the driver's seat to the seating position, the operation prohibition state of the vehicle can be quickly released.

  Further, for example, when the operator leaves the construction machine, the lock lever can be switched to the lock position, and at this time, the operation of the actuator can be surely prohibited by the operation prohibiting means. For this reason, for example, when the operator is not present, it is possible to reliably prevent the work device from being erroneously operated by the lock lever. In addition, the operator can quickly release the operation prohibition state by a simple operation that simply returns the lock lever to the unlock position.

  Therefore, it is possible to realize a construction machine that is easy for the operator to handle and highly reliable. The mechanism for prohibiting the operation of the actuator according to the position of the driver's seat and the mechanism for prohibiting the operation of the actuator according to the lock operation of the operator can be configured by a common operation prohibiting means, and two mechanisms having different uses Can be simplified into one.

  According to the second aspect of the present invention, the switching operation performed by the operator using the lock lever can be detected by the lever position detecting means, and at the time of detection, the operation of the actuator can be surely prohibited by the operation prohibiting means. Further, by using the detection result of the seat position detection unit and the detection result of the lever position detection unit, a configuration in which the operation prohibiting unit operates when two conditions are satisfied can be easily realized.

  Further, according to the invention of claim 3, by using the switching valve as the operation prohibiting means, the switching valve can be opened and closed at various desired timings by various pilot controls and the like. Thus, the operation of the actuator can be reliably permitted or prohibited.

  Further, according to the invention of claim 4, by using the electromagnetic pilot type switching valve as the operation prohibiting means, the switching valve can be easily opened and closed in accordance with the energized state of the solenoid portion, whereby the actuator The operation of can be reliably permitted or prohibited. Further, between the power source and the ground, for example, two switches constituting the seat position detecting means and the lever position detecting means and the solenoid portion of the switching valve can be connected in series.

  Thus, for example, the solenoid part of the switching valve can be energized or de-energized depending on whether both detection means are in the detection state or at least one detection means is in the non-detection state. In addition, it is possible to easily configure a circuit in which the switching valve operates when two conditions are satisfied.

  Hereinafter, as a construction machine applied to an embodiment of the present invention, a small hydraulic excavator will be described as an example and described in detail with reference to the accompanying drawings.

  In the figure, reference numeral 1 denotes a small hydraulic excavator, and the hydraulic excavator 1 is mounted on a self-propelled lower traveling body 2 and is pivotably mounted on the lower traveling body 2 via a turning device 3. 2 and the upper revolving body 4 constituting the vehicle body, and a work device 5 provided on the front side of the upper revolving body 4 so as to be able to move up and down.

  The lower traveling body 2 is provided with left and right traveling motors 2A and 2B for traveling the vehicle body, and the turning device 3 is provided with a turning motor 3A for turning the upper turning body 4 on the lower traveling body 2. It has been. As shown in FIGS. 1 and 4, the upper swing body 4 includes a swing frame 4A formed as a support structure, an exterior cover 6, a driver's seat 8, and a detection switch (described later) mounted on the swing frame 4A. 9, 17, lever stand 10, levers 11 to 16, engine 18, hydraulic pumps 22 and 25, hydraulic oil tank 23, control valve 27, hydraulic pilot valve 28, switching valve 29 and the like.

  Further, the working device 5 includes a swing post 5A attached to the front portion of the swing frame 4A so as to be swingable in the left and right directions, a boom 5B attached to the swing post 5A so as to be able to move up and down, and the boom 5B. Arm 5C attached to the tip of the arm 5C, a bucket 5D rotatably attached to the tip of the arm 5C, and a boom cylinder 5E for operating the boom 5B, arm 5C, and bucket 5D, respectively. , Arm cylinder 5F and bucket cylinder 5G. Each cylinder 5E, 5F, 5G constitutes an actuator together with the traveling motors 2A, 2B and the turning motor 3A.

  6 is an exterior cover provided on the rear side of the upper swing body 4, and the exterior cover 6 includes devices such as an engine 18, hydraulic pumps 22 and 25, and a hydraulic oil tank 23 mounted on the rear side of the swing frame 4 </ b> A. Covering. Further, as shown in FIG. 2, a frame-shaped mount portion 7 on which the driver's seat 8 is mounted is provided on the upper side of the exterior cover 6, and the mount portion 7 includes components such as electrical components (not shown). 2) and a seat position detection switch 9 to be described later are attached.

  A driver's seat 8 is mounted on the exterior cover 6 using the mount portion 7. The driver seat 8 is attached to the mount portion 7 by a support shaft 8A on the front side, and the front and rear are centered on the support shaft 8A. It can be rotated in the direction. Further, on the lower side of the driver's seat 8, there are provided a plurality of leg portions 8B that are made of an elastic material such as rubber and elastically support the driver's seat 8.

  The driver's seat 8 is normally held at a seating position where an operator is seated, as indicated by a solid line in FIG. In this seating position, each leg portion 8B of the driver's seat 8 abuts on the mount portion 7, and each component in the mount portion 7 is covered by the driver seat 8.

  Further, for example, when parts replacement in the mount portion 7, inspection work, etc. are performed, the driver's seat 8 is rotated so as to be tilted forward from the seating position and moved to the front position indicated by the phantom line in FIG. Thereby, an operator etc. can perform various maintenance work etc., exposing the components in the mount part 7 exposure.

  Reference numeral 9 denotes a seat position detection switch as a seat position detection means. The seat position detection switch 9 is provided in the mount portion 7 at a position corresponding to the leg portion 8B of the driver seat 8, for example, as shown in FIGS. Thus, it is detected whether or not the driver's seat 8 is in the seating position. The detection switch 9 includes, for example, two terminals 9A, a contact 9B that can be opened and closed between the terminals 9A, and a biasing spring 9C that biases the contact 9B in a direction away from the terminal 9A. And is configured as a normally open switch.

  When the driver's seat 8 is in the seating position, the contact 9B of the detection switch 9 is pushed by the leg 8B of the driver's seat 8 to contact each terminal 9A, and the contact 9B is held in the closed position. . When the driver's seat 8 is rotated to the front position, as shown in FIG. 6, the leg portion 8B is separated from the contact 9B of the detection switch 9, and the contact 9B is switched to the open position by the biasing spring 9C.

  Reference numeral 10 denotes a lever stand which is positioned on the front side of the driver's seat 8 and is erected on the upper swing body 4. The lever stand 10 includes work levers 11 and 12, travel levers 13 and 14 described later, an accelerator lever 15, a lock A lever 16 and the like are provided.

  Reference numerals 11 and 12 denote left and right working levers 11 and 12 mounted on the upper side of the lever stand 10, respectively. These working levers 11 and 12 are moved forward and backward by an operator as shown in FIGS. Tilt operation left and right. In this case, the left work lever 11 turns the upper swing body 4 or turns the arm 5C of the work device 5, for example, and the right work lever 12 lifts the boom 5B of the work device 5, for example. The bucket 5D is rotated.

  Reference numerals 13 and 14 denote left and right travel levers as other operation devices attached to the upper side of the lever stand 10, and these travel levers 13 and 14 are tilted forward and backward by the operator, Forward or backward, or turn left or right. Further, an accelerator lever 15 that increases or decreases the engine speed by tilting and a lock lever 16 that will be described later are provided on the side surface of the lever stand 10.

  Reference numeral 16 denotes a left and right lock lever provided on a side surface portion of the lever stand 10, and this lock lever 16 is usually called a gate lock lever or a passenger lever. The lock lever 16 is a lever for locking the operation of the vehicle when the operator leaves the excavator 1, for example, and is between a lock release position indicated by a solid line and a lock position indicated by a virtual line in FIG. Can be switched with. In this case, the left and right lock levers 16 are connected to each other, and rotate integrally when the operator tilts one of the lock levers 16.

  When the driver's seat 8 is in the seating position, the operator can move the vehicle body or turn the upper swing body 4 by holding the lock lever 16 in the unlock position, and the work device 5 can be turned on. Can be operated. Further, when the lock lever 16 is switched to the locked position, a switching valve 29 described later is actuated so that, for example, traveling of the vehicle body, turning operation of the upper turning body 4 and operation of the work device 5 are all prohibited. .

  Reference numeral 17 denotes a lever position detection switch as lever position detection means. The lever position detection switch 17 is provided on the lever stand 10 at a position corresponding to the lock lever 16, for example, as shown in FIGS. Whether or not 16 is in the unlock position is detected.

  Here, the detection switch 17 includes, for example, two terminals 17A, a contact 17B disposed so as to be openable and closeable between the terminals 17A, and a biasing spring that biases the contact 17B in a direction away from the terminal 17A. 17C, and is configured as a normally open switch.

  When the lock lever 16 is in the unlocked position, the contact 17B of the detection switch 17 is pushed by the lock lever 16 to contact each terminal 17A, and the contact 17B is held in the closed position. When the lock lever 16 is switched to the lock position, as shown in FIG. 7, the lock lever 16 is separated from the contact point 17B of the detection switch 17, and the contact point 17B is switched to the open position by the biasing spring 17C.

  As a result, in the present embodiment, when both the seat position detection switch 9 and the lever position detection switch 17 are in the closed position, the switching valve 29 described later is switched to the supply position (a) to change the vehicle body and When the operation of the work device 5 is permitted and one or both of the detection switches 9 and 17 are in the open position, the operation of the vehicle body and the work device 5 is performed by switching the switching valve 29 to the shut-off position (b). The configuration is prohibited.

  Next, the drive system of the hydraulic excavator 1 will be described with reference to FIGS. 4 and 5. First, reference numeral 18 denotes an engine mounted on the upper swing body 4 as a power source for the vehicle. The engine 18 is provided with an electric starter 18A for starting it, and the starter 18A is connected between a power source 19 such as a battery mounted on the vehicle and a ground 20.

  Reference numeral 21 denotes a controller that controls the engine. The controller 21 energizes the starter 18A from the power source 19 when, for example, a vehicle starter switch (not shown) or the like is closed, thereby starting the engine 18. .

  Further, as shown in FIG. 5, the controller 21 is provided with a detection terminal 21A for detecting an energization state of an electromagnetic pilot section 29A of a switching valve 29 described later. The detection terminal 21A is, for example, an electromagnetic pilot section 29A and a ground 20 Connected between and. The controller 21 is configured to hold the engine 18 in a stopped state without energizing the starter 18A even if the starter switch or the like of the vehicle is closed when the energization to the electromagnetic pilot unit 29A is stopped. It has become.

  Reference numeral 22 denotes a hydraulic pump as a hydraulic source driven by the engine 18. The hydraulic pump 22 sucks hydraulic oil in the hydraulic oil tank 23, and is a main pipe provided between a control valve 27 and a hydraulic pump 22 described later. Pressure oil is discharged into the passage 24.

  Reference numeral 25 denotes a pilot hydraulic pump as a pilot hydraulic source driven by the engine 18, and the pilot hydraulic pump 25 supplies pilot pressure to a pilot pipe line 26 connected to the discharge side thereof. In this case, the pilot pipe line 26 is provided between a hydraulic pilot valve 28 described later and the pilot hydraulic pump 25, and a switching valve 29 is provided in the middle of the pilot pipe line 26.

  Reference numerals 27A to 27F denote a plurality of control valves (generally referred to as control valves 27) connected to the discharge side of the hydraulic pump 22 by the main pipeline 24. The control valves 27 are constituted by, for example, hydraulic pilot type spool valves or the like. ing. The control valve 27 is switched in accordance with a pilot pressure input to a hydraulic pilot section from a hydraulic pilot valve 28, which will be described later, and the actuator (for example, motors 2A, 2B, 3A, cylinders 5E, 5F, 5G) from the hydraulic pump 22 is switched. ) To control the direction of pressure oil supplied and discharged.

  In this case, as shown in FIG. 4, the control valve 27 controls the swing control valve 27A that controls the swing motor 3A of the swing device 3, and the arm control that controls the arm cylinder 5F, the boom cylinder 5E, and the bucket cylinder 5G of the work device 5. The valve 27B, the boom control valve 27C, the bucket control valve 27D, and the left traveling control valve 27E and the right traveling control valve 27F that control the traveling motors 2A and 2B of the lower traveling body 2 are configured.

  Reference numeral 28 denotes a plurality of hydraulic pilot valves connected to the hydraulic pilot portions of the control valves 27A to 27F. Each of the hydraulic pilot valves 28 includes, for example, four pressure reducing valves 28A to 28D. Here, for example, the hydraulic pilot valve 28 located on the left side in FIG. 5 is connected to the left working lever 11 and connected to the turning control valve 27A and the arm control valve 27B.

  For example, when the left work lever 11 is tilted forward, backward, left, or right, the pilot corresponding to the amount of lever operation is supplied from the left hydraulic pilot valve 28 to the swing control valve 27A or the arm control valve 27B. Pressure is output and the corresponding control valve is switched. Thereby, the upper turning body 4 can be turned or the arm 5C can be moved up and down.

  The hydraulic pilot valve 28 located on the right side is coupled to the right working lever 12 and is connected to the boom control valve 27C and the bucket control valve 27D. When the right working lever 12 is tilted, the boom control valve 27C or the bucket control valve 27D is switched by the right hydraulic pilot valve 28, whereby the boom 5B and the bucket 5D can be operated.

  Further, the central hydraulic pilot valve 28 is connected to the left and right traveling levers 13 and 14 and is connected to the left traveling control valve 27E and the right traveling control valve 27F. When the traveling levers 13 and 14 are tilted, the left traveling control valve 27E or the right traveling control valve 27F is switched by the central hydraulic pilot valve 28, and the vehicle can travel.

  Reference numeral 29 is a switching valve as an operation prohibiting means that can be opened and closed in the middle of the pilot line 26, for example. The switching valve 29 holds the driver's seat 8 in the seating position, and the lock lever 16 is locked. When in the release position, each actuator (for example, motors 2A, 2B, 3A, cylinders 5E, 5F, 5G) mounted on the hydraulic excavator 1 is permitted to operate. It is forbidden.

  Here, as shown in FIG. 5, the switching valve 29 is composed of, for example, an electromagnetic pilot type three-port two-position switching valve and the like, and includes an electromagnetic pilot portion 29A as a solenoid portion to which a signal is supplied from the power source 19 of the vehicle, And a spring 29B. In this case, between the power source 19 and the ground 20, the seat position detection switch 9, the lever position detection switch 17, and the electromagnetic pilot unit 29A are connected in series with each other. The switching valve 29 is switched between the supply position (a) and the cutoff position (b) according to the detection results of the detection switches 9 and 17, and the supply and cutoff of pressure oil to the actuator is performed using the pilot pressure. It is the structure which performs indirectly.

  In this case, when both the detection switches 9 and 17 are in the closed position, power is supplied from the power source 19 to the electromagnetic pilot portion 29A of the switching valve 29, so that the switching valve 29 is held at the supply position (a). Has been. Therefore, the pilot pressure is supplied to each hydraulic pilot valve 28 from the pilot hydraulic pump 25, and the operator can operate the desired actuator by switching the control valve 27 by operating the levers 11-14. .

  Further, when one or both of the detection switches 9 and 17 are in the open position, the energization to the electromagnetic pilot portion 29A is stopped, and the switching valve 29 is switched to the cutoff position (b) by the return spring 29B. The pilot pressure supplied to each hydraulic pilot valve 28 is shut off. As a result, the control valve 27 is held in the neutral position and the pressure oil supply to each actuator is shut off, so that the operation of the vehicle body and the work device 5 can be prohibited.

  The hydraulic excavator 1 according to the present embodiment has the above-described configuration. Next, the operation thereof will be described.

  First, when the excavator 1 is operated in a normal state, as shown in FIG. 5, the driver's seat 8 is held in the seating position, and the lock lever 16 is switched to the unlocking position. In this state, when the operator seated in the driver's seat 8 turns on the vehicle, the electromagnetic pilot portion 29A of the switching valve 29 is energized through the detection switches 9 and 17, whereby the switching valve 29 is supplied to the supply position (a). Is switched to. When the starter switch of the vehicle is closed, the controller 21 energizes the starter 18A of the engine 18 and the engine 18 is started.

  Here, for example, when the driver's seat 8 is in the front position as shown in FIG. 6 or when the lock lever 16 is in the lock position as shown in FIG. 7, at least one of the detection switches 9 and 17 is in the open position. Therefore, the electromagnetic pilot unit 29A is not energized. In this state, even if the operator closes the starter switch, the controller 21 can detect that the electromagnetic pilot unit 29A is in a non-energized state by the detection terminal 21A, stop energizing the starter 18A, and Starting can be prohibited.

  On the other hand, when both the detection switches 9 and 17 are closed, when the engine 18 is started, the pilot pressure is supplied to the hydraulic pilot valve 28 through the switching valve 29 in the supply position (a). Becomes a controllable state. Therefore, the operator can run the vehicle body or turn the upper swing body 4 by operating the work levers 11 and 12 and the travel levers 13 and 14 as necessary, and the work device 5 is operated. It is possible to perform excavation work of earth and sand.

  Further, during the work using the hydraulic excavator 1, for example, the operator interrupts the operation and checks the components in the mount portion 7, or the levers 11 to 14 get wet when temporarily getting off the vehicle during the rain. In these cases, the operator may get off the driver's seat 8, lift it, and move the driver's seat 8 to the front position.

  When the operator lifts the driver's seat 8, as shown in FIG. 6, the seat position detection switch 9 is in the open position and the switching valve 29 is switched to the shut-off position (b). The pilot pressure is no longer input from the valve 28 and is maintained in the neutral position. For this reason, even if the levers 11 to 14 are inadvertently operated, the actuators can be held in a stopped state, and the traveling of the vehicle body, the turning operation of the upper turning body 4 and the operation of the work device 5 can be prohibited. .

  Further, for example, when the operator temporarily leaves the excavator 1 with the engine running, the lock lever 16 is switched to the lock position as shown in FIG. As a result, the lever position detection switch 17 is in the open position and the switching valve 29 is switched to the shut-off position (b). In this case as well, each control valve 27 can be held at the neutral position to stop the actuator. The operation of the vehicle body and the work device 5 can be prohibited.

  Thus, in the present embodiment, since the seat position detection switch 9, the lock lever 16, the lever position detection switch 17, the switching valve 29, and the like are provided, the operator places the driver's seat 8 in the front position during the operation of the excavator 1. This can be detected by the seat position detection switch 9, and the operation of the actuator can be reliably prohibited by the switching valve 29.

  In this case, for example, even if the operator does not recognize the contact between the driver's seat 8 and the levers 11 to 14 or forgets to do so, the operator simply lifts the driver's seat 8 without depending on the operator's attention. The switching valve 29 can be automatically activated. As a result, even if the driver's seat 8 comes into contact with the levers 11 to 14 and the like at the front side position, the work device 5 and the like can be reliably prevented from performing operations unintended by the operator, and maintenance work and the like can be smoothly performed in this state Can be done.

  Then, when the operator resumes driving, the seat position detection switch 9 can be easily closed simply by returning the driver's seat 8 to the seating position, and the operator cannot operate the vehicle without performing a special release operation or the like. The state can be released promptly. Accordingly, it is possible to realize the hydraulic excavator 1 that is easy to handle by the operator and has high reliability.

  For example, when the operator leaves the excavator 1, the lock lever 16 can be switched to the lock position. The switching operation can be detected by the lever position detection switch 17, and the operation of the actuator can be surely prohibited by the switching valve 29 at the time of detection.

  For this reason, for example, when the operator is absent, the operation of the working device 5 and the like can be reliably prevented by the lock lever 16, and the hydraulic excavator 1 can be operated only when a regular operation is performed. Further, when the operator resumes the operation, the operation prohibition state can be quickly released by a simple operation that simply returns the lock lever 16 to the unlock position. Therefore, the operability of the lock operation and the release operation can be improved, and the operator's operating environment can be improved.

  In the present embodiment, a mechanism that prohibits the operation of the actuator according to the position of the driver's seat 8 and a mechanism that prohibits the operation of the actuator according to the operator's operation of the lock lever are configured by the common switching valve 29. The two mechanisms having different applications can be combined into one and simplified.

  Further, since the electromagnetic switching valve 29 is used as the operation prohibiting means, the switching valve 29 can be easily opened and closed according to the energized state of the electromagnetic pilot section 29A, and the actuator can be operated according to this opening and closing operation. The operation of can be reliably permitted or prohibited. In this case, since the switching valve 29 is provided in the pilot pipe line 26, for example, a valve device having a relatively low pressure resistance can be used as the switching valve 29, and miniaturization of parts and cost reduction can be promoted.

  Further, since the electromagnetic pilot portion 29A of the switching valve 29 and the detection switches 9, 17 are connected in series between the power source 19 and the ground 20, both the detection switches 9, 17 are closed or at least one of them is closed. The electromagnetic pilot unit 29A can be energized or de-energized depending on whether the switch is opened, and a circuit for operating the switching valve 29 when two conditions are satisfied can be easily configured. .

  Further, since the controller 21 detects the energized state of the electromagnetic pilot unit 29A and prohibits the start of the engine 18 when the power is not energized, the controller 21 may be configured such that, for example, the driver's seat 8 is at the front position or the lock lever 16 is When the vehicle is in the locked position, it is possible to prevent the engine 18 from being started even though the vehicle cannot be driven, and the engine 18 can be started when the vehicle is in an appropriate state.

  In the above embodiment, the switching valve 29 is provided in the pilot pipeline 26. However, the present invention is not limited to this. For example, by providing a switching valve in the main pipeline 24, the pressure oil supplied to each actuator may be directly cut off by the switching valve.

  In the embodiment, the detection switches 9 and 17 and the electromagnetic pilot unit 29A of the switching valve 29 are connected in series. However, the present invention is not limited to this. For example, when the detection switches 9 and 17 are connected to the input side of the controller and the switching valve 29 is connected to the output side of the controller, the controller has both detection switches 9 and 17 connected. When it is detected that the valve is in the closed position, the switching valve 29 may be driven to the supply position (a).

  In the embodiment, the position of the lock lever 16 is electrically detected by the detection switch 17. However, the lock lever of the present invention is not limited to this. For example, when the lock lever is switched to the lock position, the lock lever engages with the operation levers 11 and 12 and the travel levers 13 and 14 to mechanically lock these levers. Thus, the operation of the vehicle body or the work device 5 may be prohibited.

  Furthermore, in the embodiment, the case where the maintenance work for the components in the mount portion 7 is performed when the driver's seat 8 is set to the front side position is described as an example. However, the present invention is not limited to the maintenance work of such parts. For example, the engine, the hydraulic pump, and the like housed in the exterior cover 6 are exposed to the inside of the mount portion 7 and are operated. When the seat 8 is moved to the front position, the maintenance work of these devices may be performed.

  Furthermore, in the embodiment, a small hydraulic excavator has been described as an example of the construction machine. However, the present invention is not limited to this, and can be applied to various construction machines including, for example, medium-sized and large-sized hydraulic excavators, hydraulic cranes, load rollers, and the like.

It is a front view which shows the hydraulic excavator applied to embodiment of this invention. It is a front view which expands and shows the vehicle body of a hydraulic excavator. It is a left view which shows the vehicle body of a hydraulic shovel. It is a circuit diagram showing the whole hydraulic system of a hydraulic excavator. It is a circuit diagram which shows the connection state of a seat position detection switch, a lever position detection switch, a switching valve, etc. It is a circuit diagram which shows a connection state when a driver's seat is rotated to the front side position. It is a circuit diagram which shows a connection state when a lock lever is switched to a lock position.

Explanation of symbols

1 Excavator (construction machine)
2 Lower traveling body (car body)
2A, 2B Traveling motor (actuator)
3 Turning device 3A Turning motor (actuator)
4 Upper swing body (car body)
5 Working device 8 Driver's seat 9 Seat position detection switch (seat position detection means)
11, 12 Work lever 13, 14 Travel lever 16 Lock lever 17 Lever position detection switch (lever position detection means)
19 Power supply 20 Ground 22 Hydraulic pump (hydraulic power source)
24 main pipeline 25 pilot hydraulic pump 26 pilot pipeline 27 control valve 28 hydraulic pilot valve 29 switching valve (operation prohibiting means)
29A Electromagnetic pilot part (solenoid part)

Claims (4)

It consists of a self-propelled vehicle body and a working device provided on the vehicle body and operated by an actuator. The vehicle body is normally held at a seating position where an operator is seated and can be rotated forward from the seating position In a construction machine with a driver's seat
The vehicle body has
Seat position detecting means for detecting whether or not the driver's seat is in the seating position;
A lock lever that is switched between a locked position and an unlocked position by an operator;
When the seat position detecting means detects that the driver's seat is in the seating position and the lock lever is in the unlocked position, the actuator is allowed to operate; otherwise, the actuator A construction machine characterized by comprising an operation prohibiting means for prohibiting the operation.   The lock lever is provided with lever position detection means for detecting whether or not the lock release position is set, and the operation prohibiting means is configured to detect the actuator according to the detection result of the seat position detection means and the lever position detection means. The construction machine according to claim 1, wherein the construction machine is configured to permit or prohibit operation.   The construction machine according to claim 1, wherein the operation prohibiting unit is configured by a switching valve that supplies pressure oil to the actuator from a hydraulic source of the vehicle body or shuts off the supply.   The operation prohibiting means includes an electromagnetic pilot type switching valve that supplies pressure oil from the hydraulic source of the vehicle body to the actuator or shuts off the supply according to the energization state of the solenoid unit. The construction machine according to claim 2, wherein the seat position detecting means, the lever position detecting means, and the solenoid portion of the electromagnetic pilot type switching valve are connected in series.

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