Work vehicles

Abstract

To provide a work vehicle that includes an engine, a work device operated by drive force of an engine, and a panel displaying the state of the work device, the work vehicle allowing for actuation of the panel without driving the engine once even in such a situation that driving of the engine becomes a problem.SOLUTION: A work vehicle includes a relay circuit 78 capable of being switched between a connection state of electrically connecting a liquid crystal screen 71 and a supply power source 13 and a cut state of cutting the liquid crystal screen 71 and the supply power source 13, and a control device 76 for controlling operation of a PTO 6 on the basis of operation of a PTO switch 12 and controlling operation of the relay circuit 78 on the basis of operation of a confirmation switch 75, wherein the control device 76 switches the PTO 6 to a transmission state when a signal indicating that the PTO switch 12 is turned ON is input, switches the relay circuit 78 to the connection state, and switches the relay circuit 78 to the connection state when a signal indicating the confirmation switch 75 is turned ON is input.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to work vehicle technology. [Background technology]

[0002] BACKGROUND ART Work vehicles equipped with a mounted object (working device) having a tank capable of storing powder or granular material, which is a special transported material, and a compressor capable of pressurizing the inside of the tank, such as a powder or granular material transport vehicle, have been known for some time. In the above-mentioned work vehicle, the engine and the working device (more specifically, the compressor) are connected via a PTO (power take-off / take-over) device, and by operating the power take-off / take-over device to transmit the driving force of the engine to the working device, the compressor is driven and the working device operates. Such work vehicles are generally provided with a meter panel (panel) that displays the state of the work implement (more specifically, the pressure inside the tank) (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-2848 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, digital display screens have become widespread, and power supply is required to operate the panels. Here, the panel display is required mainly when the working device is in operation, so power is generally supplied to the panel using a PTO switch (changeover switch) that operates the drive switching device. Specifically, when the engine is running, the drive switching device is operated using the changeover switch so that the engine's driving force is transmitted to the working device, and the battery, which is the power source, is connected to the panel, and power is supplied to the panel. Therefore, for example, if the engine is stopped and the working equipment is not operating, and it becomes necessary to check the status of the working equipment (pressure in the tank) on the panel, in order to display the panel, the engine must first be started and then a selector switch must be operated to supply power to the panel. Therefore, even in a work area where idling is prohibited or in a place where noise is a problem at night, if it becomes necessary to operate the panel, the engine must be run.

[0005] The present invention has been made in consideration of the current problems described above, and has an object to provide a work vehicle that is equipped with an engine, a work implement operated by the driving force of the engine, and a panel that displays the status of the work implement, and that can operate the panel without first starting the engine, even in situations where running the engine is problematic. [Means for solving the problem]

[0006] The problem to be solved by the present invention is as described above, and the means for solving this problem will now be described.

[0007] That is, the work vehicle according to the present invention is a work vehicle comprising an engine, a working device operated by the driving force of the engine, and a drive switching device capable of switching between a transmission state in which the driving force is transmitted to the working device and a disconnection state in which the transmission of the driving force to the working device is interrupted, and is equipped with a changeover switch for switching between the transmission state and the disconnection state of the drive switching device, a panel that displays the state of the working device, a power supply that supplies power to the panel, a relay circuit that is switchable between a connected state in which the panel and the power supply are electrically connected and a disconnection state in which the panel and the power supply are electrically disconnected, a confirmation switch for switching between the connected state and the disconnection state of the relay circuit, and a control device that controls the operation of the drive switching device based on the operation of the changeover switch, and controls the operation of the relay circuit based on the operation of the confirmation switch, and is characterized in that the control device switches the drive switching device to the transmission state and switches the relay circuit to the connected state when a signal indicating that the changeover switch has been turned on is input, and switches the relay circuit to the connected state when a signal indicating that the confirmation switch has been turned on is input. In this way, in the present invention, simply by turning on the confirmation switch, the panel and the power supply are connected via the relay circuit, so even in situations where running the engine is problematic, the panel can be operated to display the status of the working equipment without having to start the engine first.

[0008] In the work vehicle according to the present invention, it is preferable that the control device switches the relay circuit to a disconnected state when a predetermined time has elapsed since the confirmation switch was turned on. With this configuration, the panel can be maintained in an operating state for a long period of time, and the power supply that supplies power to the panel can be prevented from running out of battery (waste of power).

[0009] In addition, it is preferable that the control device according to the present invention maintains the relay circuit in a connected state even after the predetermined time has elapsed when a signal indicating that the change-over switch has been turned on is input. With this configuration, when the changeover switch is turned on, the panel remains in operation regardless of the passage of the specified time, and displays the status of the work device, allowing the worker to continue working without worrying about the panel suddenly stopping operation.

[0010] Furthermore, in the work vehicle of the present invention, it is preferable that the confirmation switch is configured as a momentary operation type switch, and that the control device switches the relay circuit to a disconnected state without waiting for the predetermined time to elapse when a signal indicating that the confirmation switch has been turned on is input again before the predetermined time has elapsed. With this configuration, when it is no longer necessary to operate the panel to display the status of the work device, the power supply to the panel can be immediately cut off without waiting for the above-mentioned specified time to elapse, thereby saving energy in the power supply and being economical.

[0011] In addition, the work vehicle of the present invention is provided with a key switch for switching between an ON state in which the engine is in a driving state and an OFF state in which the engine is in a stopped state, and the confirmation switch is configured as a momentary operation type switch, and when a signal indicating that the key switch is in the ON state and a signal indicating that the drive switching device is in a disconnected state is input, it is preferable that the control device switches the relay circuit to a connected state only while a signal indicating that the confirmation switch has been turned on is being input. Thus, in the present invention, when the engine is running and the drive switching device is in the disconnected state (i.e., a state in which the engine's driving force can be transmitted to the working wheels of the work vehicle), the panel is activated to display the status of the work equipment only while the confirmation switch is turned on. Therefore, when the work vehicle is traveling, the worker's hand is away from the confirmation switch, so the confirmation switch is not turned on and the panel is not activated, and there is no risk that the light on the display screen of the panel will be mistaken for the work vehicle's indicator lights (e.g., brake lights, turn signals, etc.). Furthermore, even when the work vehicle is in a state where it can be driven, if, for example, it suddenly becomes necessary to check the status of the work equipment, the confirmation switch can be turned on to immediately activate the panel and display the status of the work equipment. [Effects of the Invention]

[0012] The present invention has the following effects. That is, with the work vehicle according to the present invention, even in a situation where running the engine is problematic, the panel can be operated without first running the engine. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a side view showing the overall configuration of a work vehicle according to an embodiment of the present invention. [Figure 2] FIG. 2 is a front view showing the configuration of the meter panel. [Figure 3] FIG. 2 is a block diagram showing the configuration of a control device that controls a meter panel. [Figure 4] These are diagrams for explaining the operating procedure of the meter panel when the engine is stopped, where (a) is a circuit diagram showing the state when the engine is switched to the OFF state, (b) is a circuit diagram showing the state immediately after the confirmation switch is turned on, and (c) is a circuit diagram showing the state when the confirmation switch has been returned to its non-operated state. [Figure 5] This is a diagram for explaining the operating procedure of the meter panel when the engine is stopped, and is a circuit diagram showing the state immediately after the confirmation switch is turned on again without waiting for the specified output time to elapse after the confirmation switch is returned to its non-operated state. [Figure 6] FIG. 4 is a circuit diagram for explaining the operation procedure of the meter panel when the PTO is in a transmission state. [Figure 7] 4 is a circuit diagram for explaining the operation procedure of the meter panel when the engine is in a driving state and the PTO is in a disengaged state. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, one embodiment of the present invention will be described with reference to FIGS. For convenience in the following description, the front-rear direction and the up-down direction of the work vehicle 1 will be defined by the directions of the arrows shown in FIG.

[0015] [Overall configuration of work vehicle 1] First, the overall configuration of a work vehicle 1 embodying the present invention will be described with reference to FIGS. 1 and 3. FIG. The work vehicle 1 in this embodiment is, for example, a powder transport vehicle that transports powder or granular material (for example, cement, lime, or chemicals, etc.) which is a special transport item.

[0016] The configuration of the work vehicle 1 is not limited to this embodiment, and may be any vehicle that is desired to be able to check the status of the work equipment when the engine 3 is stopped and the work equipment is not operating.

[0017] For example, the work vehicle 1 may be a dump truck equipped with a scale, etc., in which it is desirable to be able to check the scale by stopping the engine 3 when loading earth and sand as transported material. In addition, when loading transported items such as garbage at night, the work vehicle 1 may be a garbage truck with a weighing scale, etc., which requires the engine 3 to be stopped to prevent noise when loading, and which is desirable for the weighing scale to be visible when garbage is placed in the hopper without operating the loading device. Furthermore, the work vehicle 1 may be a tank truck equipped with a scale, etc., in which the transported goods are flammable materials such as gasoline, and the engine 3 must be stopped to load the goods into the tank, but it is desirable to perform the loading work of the goods while checking the scale.

[0018] As shown in Figure 1, the work vehicle 1 has a chassis 2 that extends in the direction of travel (in this embodiment, the front-to-rear direction), and the chassis 2 is equipped with an engine 3 (see Figure 3) that is a driving source for traveling, a tank 4 that can store powdered or granular material, a compressor 5 that can supply pressurized air into the tank 4, and a PTO 6 (see Figure 3) that can transmit and cut off the driving force of the engine 3 to the compressor 5.

[0019] Here, the tank 4 and the compressor 5 are an example of a working device according to the present invention, and are operated when the compressor 5 is driven by the driving force of the engine 3. In addition, the PTO 6 is an example of a drive switching device according to the present invention, and as shown in FIG. 3, is provided between a drive connection mechanism (not shown) that connects the engine 3 and the compressor 5, and is configured to be able to switch between a transmission state in which the driving force of the engine 3 is transmitted to the compressor 5 and a cut-off state in which the transmission of the driving force of the engine 3 to the compressor 5 is cut off.

[0020] As shown in FIG. 1, the work vehicle 1 is provided with a meter panel 7 that can display the status of the above-mentioned work equipment (in this embodiment, the pressure inside the tank body 41 and discharge pipe 45, which will be described later, and the rotation speed of the compressor 5, etc.), and is arranged on the side of the top surface of the chassis 2. The detailed configuration of the meter panel 7 will be described later.

[0021] The tank 4 comprises a tank body 41 having an approximately hollow cylindrical shape extending in the front-to-rear direction, a plurality of manhole forming tubes 42 (three in this embodiment) fixedly installed at the top of the tank body 41 at a distance in the front-to-rear direction, and a circular discharge outlet forming body 43 provided at the lower rear end of the tank body 41. In addition, an outlet (not shown) that connects the inside and outside of the tank body 41 is provided on the inner side of the outlet forming body 43, and the tank 4 is equipped with an approximately conical tapered hatch 44 that can open and close the outlet, and an outlet pipe 45 that is connected to the protruding end of the hatch 44 and extends rearward. The discharge port and the discharge pipe 45 are in communication with each other through the internal space of the hatch 44 .

[0022] Each manhole forming tube 42 forms a manhole through its inner periphery for introducing powdered material into the tank main body 41 and for performing maintenance on the tank main body 41, and is configured to be able to be opened and closed as appropriate using a manhole cover 46.

[0023] The discharge pipe 45, together with the hatch 44, is made of a highly rigid steel material. An opening / closing valve 47, such as a butterfly valve, is provided at one end of the discharge pipe 45 (the end on the hatch 44 side), and the opening / closing valve 47 can be opened and closed appropriately outside the tank body 41 using the attached operating lever 47a.

[0024] During normal times, for example, when the work vehicle 1 is traveling, the discharge pipe 45 is closed by operating the on-off valve 47 to the closed state. When the powder or granular material is discharged from the tank body 41, the discharge pipe 45 is opened by operating the on-off valve 47 to the open state.

[0025] During the above-mentioned discharge, one end of a discharge hose 8, such as a delivery hose, is detachably connected to the other end of the discharge pipe 45 (the end opposite the hatch 44 side), and the other end of the discharge hose 8 is connected to a powder and granular material storage container 9, such as a silo.

[0026] A tank pivotal shaft 21 having an axial direction horizontal (in this embodiment, left-right direction) is provided at the rear end of the chassis 2, and the tank body 41 is swingably connected to the chassis 2 at the rear end, in front of and below the hatch 44, so as to tilt diagonally upward and rearward around the tank pivotal shaft 21, i.e., dump.

[0027] In addition, at the front end of the chassis 2, a tilting actuator 10 consisting of, for example, a telescopic (registered trademark) pick-type lift cylinder is interposed between the upper surface of the chassis 2 and the front end of the tank body 41, and when the tilting actuator 10 is extended, the tank body 41 is tilted (dumped) diagonally upward and rearward. A hydraulic supply system (not shown) including a hydraulic pump that can supply hydraulic pressure to the tilting actuator 10 as needed is mounted at an appropriate position on the chassis 2.

[0028] Furthermore, a compressor 5 is mounted at an appropriate position on the chassis 2 (in this embodiment, midway in the front-rear direction and at the bottom of the chassis 2) to supply pressurized air to the inside of the tank body 41 and the inside of the discharge pipe 45, respectively. The compressor 5, the tank body 41, and the discharge pipe 45 are connected by a compressor pipe 51 extending rearward from the compressor 5, and an ejector pipe 52 and an air pipe 53 provided downstream of the compressor pipe 51 (i.e., downstream in the flow direction of the compressed air), and the compressor pipe 51 is supported by the chassis 2 via a support member or the like (not shown).

[0029] Specifically, the compressor pipe 51 branches into two at the downstream end, with one branch (hereinafter referred to as the "first branch 51a") connected to the upstream end of the ejector pipe 52 (i.e., the upstream end in the flow direction of the compressed air), and the other branch (hereinafter referred to as the "second branch 51b") connected to the upstream end of the air pipe 53.

[0030] The downstream end of the ejector pipe 52 is connected to the discharge pipe 45 , and the downstream end of the air pipe 53 is connected to the tank body 41 . As a result, the compressor 5, the tank body 41, and the discharge pipe 45 are communicated with each other by the compressor pipe 51, the ejector pipe 52, and the air pipe 53 so that pressurized air can be supplied.

[0031] A first check valve 54 is provided on the upstream side of the ejector pipe 52 to allow only the flow of compressed air from the compressor pipe 51 to the downstream side of the ejector pipe 52. Further, on the upstream side of the air pipe 53, a second check valve 55 is provided which allows only the flow of compressed air from the compressor pipe 51 toward the downstream side of the air pipe 53.

[0032] A hatch pivot shaft 48 having an axial direction horizontal (left-right direction in this embodiment) is provided at the upper end of the discharge port forming body 43, and the hatch 44 is swingably connected to the discharge port forming body 43 via the hatch pivot shaft 48, and is configured to be able to swing diagonally upward and rearward around the hatch pivot shaft 48, thereby opening a discharge port (not shown) provided on the inner periphery of the discharge port forming body 43.

[0033] In addition, a plurality of clamping means (not shown) are arranged at equal intervals around the periphery of the discharge port forming body 43, and the hatch 44 is held to the discharge port forming body 43 by these clamping means, thereby enabling the discharge port to be securely closed. As the clamping means, for example, a conventionally known one-touch type clamping means used to hold the hatch of a powder transport vehicle can be used.

[0034] The hatch pivot shaft 48 may be provided at the side end (right end or left end) or the lower end of the discharge port forming body 43, and the hatch 44 may be configured to be able to open the discharge port by swinging sideways (right or left) or diagonally downward and rearward around the hatch pivot shaft 48. In addition, the hatch 44 may be configured to be detachably fixed to the discharge port forming body 43 via a fastening member consisting of, for example, multiple bolts, without having the above-mentioned clamping means or hatch pivot shaft 48.

[0035] The ejector pipe 52 assists and promotes the discharge of powder and granular material from the discharge pipe 45 by flowing pressurized air downstream and injecting the pressurized air into the discharge pipe 45. Its downstream end is inclined toward the discharge pipe 45 and is inserted into the peripheral wall of the discharge pipe 45 to form a communication hole (not shown) that communicates with the inside of the discharge pipe 45.

[0036] Although not shown, the ejector piping 52 is composed of an intermediate piping section made of a flexible hose member, an upstream piping section connected to the upstream end of the intermediate piping section, and a downstream piping section connected to the downstream end of the intermediate piping section, and is connected to the first branch section 51a of the compressor piping 51 via the upstream piping section, and is connected to the discharge pipe 45 via the downstream piping section. Furthermore, the upstream piping and downstream piping are formed from highly rigid steel material, and are detachably connected to the intermediate member by a joint member (not shown) consisting of a conventionally known coupling that can be locked and unlocked with a single touch.

[0037] On the other hand, the downstream end of the air pipe 53 is inclined toward the lower side of the rear end of the tank body 41, and is inserted into the peripheral wall of the tank body 41 to form a communication hole (not shown) that communicates with the inside of the tank body 41, and is fixed (e.g., welded) to the tank body 41.

[0038] Here, inside the tank body 41, a first air passage 41a is defined in the lower part of the inner wall as a flat space extending long in the front-to-rear direction for guiding the pressurized air flowing in from the air piping 53 to the front side of the tank body 41. Additionally, a breathable, plate-like canvas 41b is installed in a substantially horizontal position on the bottom of the tank body 41 so as to be supported by the side wall 41a1 of the first air passage 41a.

[0039] Between the canvas 41b and the bottom surface of the tank body 41, a second air passage 41c is defined as a flat space extending long in the front-to-rear direction, and the first air passage 41a and the second air passage 41c are connected to each other via a plurality of through holes 41a2·41a2··· provided in the front part of the side wall 41a1.

[0040] In the tank body 41 having such an internal configuration, when compressed air is supplied to the rear end of the tank body 41 from the compressor 5 via the compressor piping 51 and the air piping 53, the supplied compressed air flows through the first air passage 41a and is led to the front side of the tank body 41, flows into the second air passage 41c via the multiple through holes 41a2·41a2···, and then flows again through the second air passage 41c and is led to the rear side of the tank body 41, and is sprayed upward within the tank body 41 through almost the entire surface of the canvas 41b. As a result, the inside of the tank body 41 is pressurized by the compressed air that is blown up and ejected through the canvas 41b, and when the powder and granular material stored in the tank body 41 is discharged toward the discharge pipe 45, the sliding flow of the powder and granular material present on the canvas 41b toward the rear side of the tank body 41 is assisted and promoted, allowing the powder and granular material to be efficiently discharged toward the discharge pipe 45.

[0041] Like the ejector piping 52 described above, the air piping 53 is composed of an intermediate piping section made of a flexible hose member, an upstream piping section connected to the upstream end of the intermediate piping section, and a downstream piping section connected to the downstream end of the intermediate piping section, although these are not shown in the figure, and is connected to the second branch section 51b of the compressor piping 51 via the upstream piping section, and is connected to the lower side of the rear end of the tank body 41 via the downstream piping section. Furthermore, the upstream piping and downstream piping are formed from highly rigid steel material, and are detachably connected to the intermediate member by a joint member (not shown) consisting of a conventionally known coupling that can be locked and unlocked with a single touch.

[0042] In the work vehicle 1 configured as described above, when discharge work is performed to discharge the powdery or granular material contained in the tank main body 41, the following procedure is followed. That is, when the work vehicle 1 containing a predetermined amount of powder and granular material inside the tank body 41 arrives at a predetermined destination, a discharge hose 8 is connected to the downstream end of the discharge pipe 45, and the tank body 41 is connected to a powder and granular material storage container 9 (e.g., a silo, etc.) via the discharge hose 8. When the discharge pipe 45 and the discharge hose 8 are connected, the engine 3 may be in either a running state or a stopped state.

[0043] When the engine 3 is stopped, after the tank body 41 and the powder / granular material storage container 9 are connected, first, the key switch 11 (see Figure 3) described later is operated to start the engine 3, and then the PTO switch 12 described later is operated to switch the PTO 6 to a transmission state (a state in which the driving force of the engine 3 can be transmitted to the compressor 5), and the compressor 5 is operated. Also, when the engine 3 is in a driving state, after the tank body 41 and the powder / granular material storage container 9 are connected, the PTO switch 12 is immediately operated to switch the PTO 6 to a transmission state and operate the compressor 5.

[0044] When the compressor 5 is operated, compressed air is supplied from the compressor pipe 51 through the air pipe 53 into the tank body 41 . As described above, the compressed air supplied into the tank body 41 flows sequentially through the first air passage 41a, the multiple through holes 41a2·41a2···, and the second air passage 41c, and is ejected upward within the tank body 41 through almost the entire surface of the canvas 41b. As a result, the inside of the tank body 41 is pressurized, and the sliding flow of the powder and granular material in the tank body 41 toward the rear is promoted and accelerated.

[0045] Furthermore, when the compressor 5 is operated, compressed air is supplied from the compressor pipe 51 through the ejector pipe 52 into the discharge pipe 45 . The compressed air supplied into the discharge pipe 45 pressurizes the inside of the discharge pipe 45 and flows downstream within the discharge pipe 45 as described above.

[0046] On the other hand, when the PTO 6 is switched to the transmission state, the meter panel 7 starts to operate and displays the number of revolutions of the compressor, the pressure inside the tank body 41 and the discharge pipe 45, and the like. Then, after confirming that the information displayed on the meter panel 7 has reached a predetermined level, the operator operates the operating lever 47a to open the on-off valve 47. This releases the compressed air inside the tank body 41 and the discharge pipe 45, and the powder and granular material stored in the tank body 41 together with the compressed air is efficiently discharged into the discharge hose 8 via the discharge pipe 45.

[0047] In addition, by operating the tilting actuator 10 as necessary and tilting (dumping) the tank body 41 diagonally upward toward the rear, the backward flow of the powder and granular material within the tank body 41 and the discharge of the powder and granular material from the discharge pipe 45 can be further promoted.

[0048] Furthermore, when performing maintenance work inside the tank body 41, by opening each manhole cover 46 and then opening the hatch 44, the manhole formed by the manhole forming tube 42 and the discharge outlet located on the inner periphery of the discharge outlet forming body 43 can be opened, and maintenance work inside the tank body 41 can be carried out without hindrance through these manholes and discharge outlets.

[0049] During the above-mentioned maintenance work, before opening the hatch 44, it is preferable to use a joint member (not shown) to separate the intermediate piping section (not shown) made of a hose member in the ejector piping 52 from the downstream piping (not shown) made of steel, and to separate the discharge pipe 45 connected to the hatch 44 from the discharge hose 8. This makes it possible to prevent the intermediate piping portion of the ejector piping 52 and the discharge hose 8 from interfering with the opening and closing of the hatch 44 .

[0050] Furthermore, when loading powdered or granular material into the tank body 41, the work can be carried out without any problems by opening each manhole cover 46 with the hatch 44 closed and inserting, for example, a discharge hose (not shown) connected to the discharge outlet of the facility where the powdered or granular material is stored into the manhole formed by the manhole forming tube 42.

[0051] Furthermore, when these maintenance and loading operations are performed, they are generally carried out with the engine 3 stopped, and when opening each manhole cover 46, it is necessary to confirm that any residual pressure in the tank body 41 has been sufficiently released. As will be described later, in the work vehicle 1 of this embodiment, there is no need to first start the engine 3, and the meter panel 7 can be immediately operated to display the pressure inside the tank body 41 and the discharge pipe 45, etc., so these maintenance and charging operations can be carried out more smoothly and reliably.

[0052] [Configuration of Meter Panel 7] Next, the configuration of the meter panel 7 will be described with reference to FIGS. The meter panel 7 is used in the work vehicle 1 (see Figure 1) when performing the aforementioned discharge work, input work, maintenance work, etc., and displays the status of the work device consisting of the tank 4 and compressor 5 (such as the pressure inside the tank body 41 and discharge pipe 45, and the rotation speed of the compressor 5). The meter panel 7 is used to set at least one of the upper and lower limits of the rotation speed of the compressor 5.

[0053] As shown in FIG. 2, the meter panel 7 includes a liquid crystal screen 71 that forms a display screen, a main switch 72, a rotation speed adjustment switch 73, a screen changeover switch 74, and a confirmation switch 75 that are arranged in this order from top to bottom on the side of the liquid crystal screen 71, and a control device 76 (see FIG. 3) that controls the operation of the meter panel 7.

[0054] The LCD screen 71 is an example of a panel according to the present invention, and when switched to a meter screen by the screen changeover switch 74, it displays the status of the working equipment, i.e., the measured value of the pressure gauge inside the tank body 41, the measured value of the pressure gauge inside the discharge pipe 45, and the rotation speed of the compressor 5 driven by the driving force of the engine 3 (see Figure 3). In addition, the LCD screen 71 can be switched to a maintenance screen by the screen changeover switch 74, and displays the total operating time of the compressor 5, the operating time of the compressor 5 today, the temperature of the compressor 5, error indications, error history, etc.

[0055] The main switch 72 is configured as an alternate operation toggle switch that switches between an ON state and an OFF state by tilting the operating lever upward or downward, and maintains that state.

[0056] In this embodiment, when the operating lever of the main switch 72 is tilted upward, the speed of the compressor 5 is switched to a state (ON state) in which it is possible to adjust the speed of the compressor 5 using the speed adjustment switch 73, and this state is maintained until the next operation (tilting the operating lever downward) is performed. In addition, when the operating lever of the main switch 72 is tilted downward, the rotation speed adjustment switch 73 is used to switch to a state in which the rotation speed of the compressor 5 cannot be adjusted (OFF state), and this state is maintained until the next operation (tilting the operating lever upward) is performed.

[0057] When the rotation speed adjustment switch 73 is not operated, the operating lever always returns to a biased state (OFF state) in a neutral position in a horizontal position, and when operated, it is configured as a momentary-operation toggle switch that switches to the ON state to adjust the rotation speed of the compressor 5 only while the operating lever is tilted upward or downward.

[0058] In this embodiment, when the operating lever of the rotation speed adjustment switch 73 is tilted upward, the rotation speed of the compressor 5 increases. Moreover, when the operating lever of the rotation speed adjustment switch 73 is tilted downward, the rotation speed of the compressor 5 decreases. Note that when the rotation speed of the compressor 5 is to be changed (increased or decreased) continuously and significantly, this can be done by keeping the operating lever tilted upward or downward.

[0059] When the screen changeover switch 74 is not in operation, the operating lever always returns to a biased state (OFF state) in a neutral position in a horizontal position, and when in operation, tilting the operating lever upward turns the switch to the ON state, which switches the display content of the LCD screen 71, and the switch is configured as a momentary-operation toggle switch.

[0060] In this embodiment, each time the operating lever of the screen changeover switch 74 is tilted upward, the display screen alternates between a meter screen that displays the status of the working equipment (such as the pressure inside the tank body 41 and the discharge pipe 45, and the rotation speed of the compressor 5) and a maintenance screen that is displayed when adjusting the rotation speed of the compressor 5.

[0061] When the confirmation switch 75 is not in operation, the operating lever always returns to a biased state (OFF state) in a neutral position where the switch is tilted downward, and when in operation, the confirmation switch 75 is configured as a momentary-operation toggle switch that turns on the LCD screen 71 by tilting the operating lever upward to turn it on.

[0062] In this embodiment, when the engine 3 is stopped, for example, when the work vehicle 1 is being put into operation or during maintenance work, the LCD screen 71 is turned on by tilting the operating lever of the confirmation switch 75 upward, and then the LCD screen 71 is turned off after waiting for a predetermined time to elapse. Furthermore, if the operating lever, which has been temporarily returned to the neutral position, is tilted upward again without waiting for the predetermined time to elapse, the liquid crystal screen 71 is forcibly turned off.

[0063] On the other hand, when the engine 3 is running and the PTO switch 12 (see FIG. 3), which will be described later, is turned on, such as during discharge work on the work vehicle 1, the LCD screen 71 will continue to be lit even after the operating lever of the confirmation switch 75 has returned to the neutral position, regardless of the passage of the above-mentioned predetermined time. In addition, when the engine 3 is running and the PTO switch 12 is turned off, such as when the work vehicle 1 is traveling, the LCD screen 71 will remain lit only while the operating lever of the confirmation switch 75 is tilted upward.

[0064] Although the confirmation switch 75 in this embodiment is configured as a momentary operation type toggle switch, the present invention is not limited to this and may be configured as, for example, an alternate operation type toggle switch.

[0065] As shown in FIG. 3, the control device 76 is electrically connected to the liquid crystal display 71, the main switch 72, the rotation speed adjustment switch 73, the screen changeover switch 74, and the confirmation switch 75 described above. In addition, the control device 76 is electrically connected to the key switch 11, the PTO switch 12, and the power supply 13 (see FIG. 4) arranged outside the meter panel 7 via a wire harness 77 (see FIG. 2) or the like.

[0066] Here, as shown in FIG. 4(a), for example, the key switch 11 is connected to a first input terminal 76a of the control device 76 via a first wiring a1.

[0067] In addition, the power supply 13 is connected to the first input terminal 75a of the confirmation switch 75 via the second wiring b1, and is also connected to the contact side input terminal 78a of the relay circuit 78 described later via the third wiring b2 branching off from the second wiring b1.

[0068] On the other hand, the confirmation switch 75 is connected to the second input terminal 76b of the control device 76 via a fourth wiring c1 connected to the second input terminal 75b, and is connected to the power supply terminal 76c of the control device 76 via a fifth wiring d1 connected to the output terminal 75c. In addition, the relay circuit 78 is connected to the power supply terminal 76c of the control device 76 by the sixth wiring d2 connected to the contact side output terminal 78b merging with the fifth wiring d1, and is also connected to the output terminal 76d of the control device 76 via the seventh wiring e1 connected to the terminal on the operating part side (the terminal connected to the diode in this embodiment).

[0069] Therefore, the power supply 13 is connected to the control device 76 via a check switch 75 and a relay circuit 78 connected in parallel.

[0070] Furthermore, the PTO switch 12 is connected to the operating unit side (diode side) of the relay circuit 78 via an eighth wiring f1, and is thereby connected to the control device 76 via the relay circuit 78.

[0071] The key switch 11 is a switch for switching between an ON state in which the engine 3 is in a driving state and an OFF state in which the engine 3 is in a stopped state. The key switch 11 can generally be switched between three modes: a stop mode in which the engine 3 is stopped and the electrical equipment in the driver's seat is not energized; an accessory mode in which the engine 3 is stopped and the electrical equipment in the driver's seat is energized; and a driving mode in which the engine 3 is running and the electrical equipment in the driver's seat is energized. In this embodiment, however, "engine 3 switches to the ON state" means "engine 3 switches to the driving mode," and "engine 3 switches to the OFF state" means "engine 3 switches to the stop mode or accessory mode."

[0072] The power supply 13 is a battery mounted on the work vehicle 1, and as described above, is electrically connected to the control device 76 via the confirmation switch 75 and the relay circuit 78, and supplies power to the LCD screen 71 via the control device 76.

[0073] The PTO switch 12 is an example of a change-over switch according to the present invention, and when turned on, changes the state of the PTO 3 to a transmission state in which the driving force of the engine 3 is transmitted to the compressor 5, and when turned off, changes the state to a blocking state in which the transmission of the driving force to the compressor 5 is blocked.

[0074] In addition, the relay circuit 78 is a control device that, by operating the confirmation switch 75 or the PTO switch 12 as described below, can switch between a connected state in which the LCD screen 71 and the power supply 13 are electrically connected and a disconnected state in which the LCD screen 71 and the power supply 13 are electrically disconnected via the control device 76. In this embodiment, the relay circuit is configured as a mechanical relay type (contact type) having contacts, but is not limited to this and may be configured as a MOS FET type (contactless type) relay circuit that does not have contacts, for example.

[0075] Furthermore, as described above, the first input terminal 75a of the confirmation switch 75 is connected to the contact side input terminal 78a of the relay circuit 78 via the second wiring b1 and the third wiring b2, and the output terminal 75c of the confirmation switch 75 is connected to the contact side output terminal 78b of the relay circuit 78 via the fifth wiring d1 and the sixth wiring d2, and the confirmation switch 75 functions as a switch that switches the relay circuit 78 between a connected state and a disconnected state.

[0076] As shown in FIG. 3, the control device 76 includes a memory unit 76e that stores in advance predetermined programs for controlling the operation of the meter panel 7 and predetermined set values that can be set arbitrarily (for example, the output time of an electrical signal output from the output terminal 76d of the control device 76 to the relay circuit 78, as described below), and a calculation unit 76f that executes various calculation processes based on the programs. As described below, the control device 76 operates the relay circuit 78 based on instruction signals (electrical signals) input by operating the key switch 11, the PTO switch 12, and the confirmation switch 75, causing the meter panel 7 to perform predetermined operations.

[0077] It goes without saying that the control device 76 causes the meter panel 7 to perform the above-mentioned predetermined operations (e.g., adjusting the compressor rotation speed) based on instruction signals (electrical signals) input by operating the main switch 72, the rotation speed adjustment switch 73, and the screen changeover switch 74.

[0078] <Operation procedure of the meter panel 7 when the engine 3 is stopped> First, the operation procedure of the meter panel 7 when the engine 3 is stopped, such as when the work vehicle 1 is being put into operation or undergoing maintenance, will be described with reference to FIG.

[0079] As shown in Figure 4(a), when the engine 3 (see Figure 3) is stopped, the key switch 11 is switched to the OFF state, and no instruction signal (electrical signal) is input to the control device 76 through the first wiring a1.

[0080] Furthermore, when the confirmation switch 75 is not being operated, it is in an OFF state biased in the neutral position, and the second input terminal 75b and the output terminal 75c are in contact (i.e., the first input terminal 75a and the output terminal 75c are not in contact).

[0081] Furthermore, since the engine 3 is stopped, the instruction signal (electrical signal) from the PTO switch 12 is not input to the relay circuit 78 through the eighth wiring f1, and the contact side input terminal 78a and the contact side output terminal 78b of the relay circuit 78 are in a non-contact state (disconnected state).

[0082] Therefore, the power supply 13 is not electrically connected to the control device 76 via either the check switch 75 or the relay circuit 78 (hereinafter referred to as the "non-energized state"). In other words, the power supply 13 and the liquid crystal screen 71 are electrically disconnected, and the liquid crystal screen 71 is in an unlit state.

[0083] In this state, as shown in Figure 4(b), when the confirmation switch 75 is turned on to bring the first input terminal 75a and the output terminal 75c into contact (i.e., the second input terminal 75b and the output terminal 75c into a non-contact state), the second wiring b1 and the fifth wiring d1 are connected, and the power supply 13 is electrically connected to the control device 76 via the confirmation switch 75 (hereinafter referred to as the "energized state"). In other words, the power supply 13 and the liquid crystal display 71 are electrically connected via the control device 76 .

[0084] As a result, power from the power supply 13 is input to the power terminal 76c of the control device 76 via the second wiring b1, the confirmation switch 75, and the fifth wiring d1, and the control device 76 immediately supplies the input power to the LCD screen 71, turning on the LCD screen 71 and displaying a specified screen. Furthermore, when power from the power supply 13 is input to the power supply terminal 76c, the control device 76 immediately outputs an instruction signal (electrical signal) to the relay circuit 78 from the output terminal 76d through the seventh wiring e1.

[0085] When an instruction signal (electrical signal) is input from the control device 76, the contact-side input terminal 78a and the contact-side output terminal 78b of the relay circuit 78 are brought into contact (connected) state. As a result, the third wiring b2 and the sixth wiring d2 are connected, the power supply 13 is electrically connected to the control device 76 not only through the confirmation switch 75 but also through the relay circuit 78, and the power supply 13 and the LCD screen 71 are electrically connected via the control device 76.

[0086] In this way, once a signal indicating that the confirmation switch 75 has been turned on is input to the power supply terminal 76c, the control device 76 in this embodiment outputs an instruction signal (electrical signal) from the output terminal 76d to the relay circuit 78, switches the relay circuit 78 to the connected state, lights up the liquid crystal screen 71, and displays a predetermined screen.

[0087] Therefore, as shown in FIG. 4(c), even if the confirmation switch 75 is subsequently returned to its non-operated state and the second input terminal 75b and the output terminal 75c are restored to a contact state (i.e., the first input terminal 75a and the output terminal 75c are restored to a non-contact state), the connection state of the relay circuit 78 is maintained, so that the power supply 13 and the control device 76 continue to be electrically connected and the LCD screen 71 remains lit.

[0088] Meanwhile, the control device 76 is provided with an output time (for example, one hour in this embodiment) in advance as a default value that can be set arbitrarily when outputting an instruction signal (electrical signal) from the output terminal 76d to the relay circuit 78.

[0089] Specifically, as shown in FIG. 4(c), when the confirmation switch 75 is returned from an ON state to a non-operated state, and the second input terminal 75b and the output terminal 75c return to a contact state (i.e., the first input terminal 75a and the output terminal 75c return to a non-contact state), an instruction signal (electrical signal) is input to the second input terminal 76b.

[0090] When an instruction signal (electrical signal) is input to the second input terminal 76b, the control device 76 immediately starts counting the elapsed time. When the elapsed time reaches the output time, the control device 76 stops outputting the instruction signal (electrical signal) from the output terminal 76d to the relay circuit 78.

[0091] As a result, as shown in FIG. 4(a), the contact side input terminal 78a and the contact side output terminal 78b of the relay circuit 78 are in a non-contact state (disconnected state), and the power supply 13 is again in a non-conductive state via either the confirmation switch 75 or the relay circuit 78, the supply of power to the LCD screen 71 is stopped, and the LCD screen 71 is turned off.

[0092] In this way, in this embodiment, when a predetermined time (output time) has elapsed since the confirmation switch 75 was turned on (more specifically, since the confirmation switch 75 was returned from the on-operated state to the non-operated state again, i.e., since an instruction signal (electrical signal) was input to the second input terminal 76b), the control device 76 immediately switches the relay circuit 78 to the disconnected state and turns off the LCD screen 71.

[0093] Therefore, by performing such control, for example, the LCD screen 71 can be kept lit for a long period of time, thereby preventing the power supply 13 that supplies power to the LCD screen 71 from running out of battery (waste of power).

[0094] In FIG. 4(c), after returning the confirmation switch 75 to the non-operated state, if the confirmation switch 75 is turned on again without waiting for the elapsed time to reach the predetermined output time, thereby bringing the first input terminal 75a and the output terminal 75c into contact (i.e., bringing the second input terminal 75b and the output terminal 75c into a non-contact state), the control device 76 will detect that the instruction signal (electrical signal) input to the second input terminal 76b has been interrupted, as shown in FIG.

[0095] When it is detected that the input of the instruction signal (electrical signal) has been interrupted, the control device 76 immediately stops outputting the instruction signal (electrical signal) from the output terminal 76d. Therefore, as shown in FIG. 4(a), the power supply 13 is de-energized via either the confirmation switch 75 or the relay circuit 78 without waiting for the elapsed time to reach the predetermined output time, the supply of power to the LCD screen 71 is stopped, and the LCD screen 71 is turned off.

[0096] In this way, when a signal indicating that the confirmation switch 75 has been turned on is input again before the predetermined time (output time) has elapsed, the control device 76 in this embodiment switches the relay circuit 78 to the disconnected state and turns off the LCD screen 71 without waiting for the predetermined time (output time) to elapse.

[0097] Therefore, by performing such control, for example, when it is no longer necessary to light up the LCD screen 71 to display the status of the working device, the power supply can be immediately cut off and the LCD screen 71 can be turned off without waiting for the lapse of the above-mentioned predetermined time (output time), thereby saving energy in the power supply 13 and being economical.

[0098] As another embodiment of the present invention, without setting in advance the output time for outputting an instruction signal (electrical signal) from the output terminal 76d to the relay circuit 78 as described above, the control device 76 may switch the relay circuit 78 to the connected state once the confirmation switch 75 is turned on (more specifically, when the confirmation switch 75 is returned from the turned on state to the non-operated state again, i.e., when an instruction signal (electrical signal) is input to the second input terminal 76b) and thereafter maintain the connected state. In this case, when the confirmation switch 75 is turned on again, the relay circuit 78 may be immediately switched to the disconnected state, and the liquid crystal screen 71 may be turned off.

[0099] Furthermore, if the confirmation switch 75 is turned on multiple times after being returned to its non-operated state, the count of the elapsed time may be started based on the timing of the first on operation, or may be started based on the timing of the last on operation.

[0100] Alternatively, the counting of the elapsed time may be started immediately after a signal indicating that the confirmation switch 75 has been turned on is input to the power supply terminal 76c and an instruction signal (electrical signal) is output from the output terminal 76d. As described above, when the confirmation switch 75 is turned on and a predetermined time (output time) elapses, the control device 76 in this embodiment immediately switches the relay circuit 78 to the disconnected state and turns off the liquid crystal screen 71. In this case, "when the confirmation switch 75 is turned on" means that counting starts when an instruction signal (electrical signal) that rises when the on-operation of the confirmation switch 75 is switched to the off-operation is input (to the second input terminal 76b), and counting starts when an instruction signal (electrical signal) that rises when the confirmation switch 75 is turned on is input (to the power supply terminal 76c). It includes both cases.

[0101] As described above, the control device 76 in this embodiment, after the confirmation switch 75 is turned on (more specifically, "after returning from the on-operated state to the non-operated state again", that is, "after an instruction signal (electrical signal) is input to the second input terminal 76b"), when a predetermined time (output time) elapses, immediately switches the relay circuit 78 to the disconnected state and turns off the liquid crystal screen 71.

[0102] Furthermore, as shown in FIG. 5, even when the confirmation switch 75 is turned on again without waiting for the elapsed time to reach the predetermined output time after the confirmation switch 75 is returned to the non-operated state, as in this embodiment, the connection state of the relay circuit 78 may be maintained and the liquid crystal screen 71 may be turned on without stopping the output of the instruction signal (electrical signal) from the output terminal 76d.

[0103] <Operation procedure of the meter panel 7 when PTO6 is in the transmission state> Next, the operation procedure of the meter panel 7 when PTO6 is in the transmission state, for example, during the discharge operation of the work vehicle 1, will be described using FIG. 6.

[0104] As a prerequisite for switching the PTO 6 (see Figure 3) to the transmission state, the engine 3 is in a driving state, so the key switch 11 is switched to the ON state, and an instruction signal (electrical signal) is input to the control device 76 via the first wiring a1.

[0105] Furthermore, when the confirmation switch 75 is not being operated, it is in an OFF state biased in the neutral position, and the second input terminal 75b and the output terminal 75c are in contact (i.e., the first input terminal 75a and the output terminal 75c are not in contact).

[0106] In this state, when the PTO switch 12 is turned on and the PTO 6 is switched to the transmission state, an instruction signal (electrical signal) is input from the PTO switch 12 to the operating unit side (diode side) of the relay circuit 78 via the eighth wiring f1.

[0107] When an instruction signal (electrical signal) is input from the PTO switch 12, the relay circuit 78 brings the contact-side input terminal 78a and the contact-side output terminal 78b into a contact state (connection state). As a result, the third wiring b2 and the sixth wiring d2 are connected, and the power supply 13 is electrically connected to the control device 76 via the relay circuit 78, so that the power supply 13 and the LCD screen 71 are electrically connected via the control device 76. The control device 76 then immediately supplies the input power to the liquid crystal screen 71, lighting up the liquid crystal screen 71 and displaying a predetermined screen.

[0108] The connected state of the relay circuit 78 is maintained until the PTO switch 12 is turned off again and the input of the instruction signal (electrical signal) to the operating section side (diode side) is cut off. Therefore, regardless of whether the confirmation switch 75 has been turned on or off, or whether the elapsed time since the switch was turned off has reached the specified output time, as long as the PTO switch 12 remains turned on, the control device 76 maintains the supply of power from the power supply 13 to the LCD screen 71, lights up the LCD screen 71, and displays a specified screen.

[0109] In this way, when a signal indicating that the PTO switch 12 has been turned on is input, the control device 76 in this embodiment keeps the relay circuit 78 in a connected state, turns on the LCD screen 71, and displays a predetermined screen, even after at least the above-mentioned predetermined time (output time) has elapsed.

[0110] Generally, when the work equipment (in this embodiment, the tank 4 and the compressor 5) is in operation, it is preferable for the worker to continue working if the LCD screen 71 remains lit while the operation continues. In this embodiment, when the PTO switch 12 is turned on, the LCD screen 71 remains lit and displays the status of the work device regardless of whether the elapsed time has reached the specified output time, so the worker can continue working without worrying about the LCD screen 71 suddenly going out.

[0111] Furthermore, when the work device is in operation, the power supply 13 that supplies power to the LCD screen 71 is constantly generating power by the engine 3, so even if the LCD screen 71 is kept lit for a long period of time, the power supply 13 will not run out of battery (waste of power).

[0112] In another embodiment of the present invention, even when the key switch 11 is switched to the ON state and the PTO switch 12 is turned on, as described above, when a predetermined time (output time) has elapsed since a signal indicating that the confirmation switch 75 has been turned on is input to the power terminal 76c, the relay circuit 78 may be switched to the disconnected state and the LCD screen 71 may be turned off.

[0113] <Operation Procedure of the Meter Panel 7 When the Engine 3 is in a Running State and the PTO 6 is in a Disconnected State> Next, the operation procedure of the meter panel 7 when the engine 3 is in a driving state and the PTO 6 is in a disconnected state, such as when the work vehicle 1 is traveling, will be described with reference to FIG.

[0114] When the engine 3 (see FIG. 3) is in a running state, the key switch 11 is switched to the ON state, and an instruction signal (electrical signal) is input to the control device 76 through the first wiring a1.

[0115] Furthermore, when the confirmation switch 75 is not being operated, it is in an OFF state biased in the neutral position, and the second input terminal 75b and the output terminal 75c are in contact (i.e., the first input terminal 75a and the output terminal 75c are not in contact).

[0116] Furthermore, when the PTO 6 is in the disconnected state, the PTO switch 12 is turned off, and no instruction signal (electrical signal) is input from the PTO switch 12 to the operating section side (diode side) of the relay circuit 78 via the eighth wiring f1. Therefore, the relay circuit 78 is in a non-contact state (disconnected state) between the contact-side input terminal 78a and the contact-side output terminal 78b.

[0117] In this state, the liquid crystal display 71 lights up and displays a predetermined screen only while the confirmation switch 75 is turned on. That is, when the confirmation switch 75 is turned on and the first input terminal 75a and the output terminal 75c are in contact (i.e., the second input terminal 75b and the output terminal 75c are not in contact), the second wiring b1 and the fifth wiring d1 are connected, and the power supply 13 is electrically connected to the control device 76 via the confirmation switch 75. In other words, the power supply 13 and the liquid crystal display 71 are electrically connected via the control device 76 .

[0118] As a result, power from the power supply 13 is input to the power terminal 76c of the control device 76 via the second wiring b1, the confirmation switch 75, and the fifth wiring d1, and the control device 76 immediately supplies the input power to the LCD screen 71, turning on the LCD screen 71 and displaying a specified screen. On the other hand, even if power from the power supply 13 is input to the power supply terminal 76c, the control device 76 does not output an instruction signal (electrical signal) from the output terminal 76d to the relay circuit 78 via the seventh wiring e1.

[0119] Therefore, when the confirmation switch 75 is subsequently returned to its non-operated state, restoring the second input terminal 75b and the output terminal 75c to a state in which they are in contact (i.e., the first input terminal 75a and the output terminal 75c are not in contact), and the signal indicating that the confirmation switch 75 has been turned on (the instruction signal (electrical signal) input to the power supply terminal 76c) is cut off, the power supply 13 is put into a non-conductive state with the control device 76 via the confirmation switch 75, so that the supply of power to the LCD screen 71 is stopped and the LCD screen 71 is turned off.

[0120] In this way, when a signal indicating that the key switch 11 is in the ON state is input to the first input terminal 76a and a signal indicating that the PTO 6 is in the disconnected state (i.e., an OFF signal in which the above-mentioned instruction signal (electrical signal) is not input from the PTO switch 12) is input to the operating section side (diode side) of the relay circuit 78, the control device 76 in this embodiment switches the relay circuit 78 to the connected state, lights up the LCD screen 71, and displays a predetermined screen only while a signal indicating that the confirmation switch 75 has been operated ON is being input.

[0121] Therefore, when the work vehicle 1 is traveling, the worker's hand is away from the confirmation switch 75, so the confirmation switch 75 is not turned on and the LCD screen 71 is not lit, and there is no risk that the light on the LCD screen 71 will be mistaken for an indicator lamp (e.g., a brake lamp or turn signal) of the work vehicle. Furthermore, even when the work vehicle 1 is in a state where it can be driven, if, for example, it suddenly becomes necessary to check the status of the work equipment, the confirmation switch 75 can be turned on to immediately light up the LCD screen 71 and display the status of the work equipment.

[0122] In another embodiment of the present invention, even if the key switch 11 is switched to the ON state and the PTO switch 12 is switched to the OFF state, as described above, when a signal indicating that the confirmation switch 75 has been switched to the ON state is input to the power supply terminal 76c, and a predetermined time (output time) has elapsed, the relay circuit 78 may be switched to the disconnected state and the LCD screen 71 may be turned off.

[0123] As described above, the work vehicle 1 in this embodiment comprises the engine 3, a work device (tank 4 and compressor 5) operated by the driving force of the engine 3, and a PTO (drive switching device) 6 that can switch between a transmission state in which the driving force is transmitted to the work device and a cut-off state in which the transmission of the driving force to the work device is cut off.

[0124] The work vehicle 1 also includes a PTO switch (changeover switch) 12 for switching between a transmission state and a disconnection state of the PTO 6, an LCD screen (panel) 71 for displaying the state of the work equipment (such as the pressure inside the tank body 41 and the discharge pipe 45, and the rotation speed of the compressor 5), a power supply 13 for supplying power to the LCD screen 71, a relay circuit 78 that can be switched between a connection state in which the LCD screen 71 and the power supply 13 are electrically connected and a disconnection state in which the LCD screen 71 and the power supply 13 are electrically disconnected, a confirmation switch 75 for switching between the connection state and disconnection state of the relay circuit 78, and a control device 76 that controls the operation of the PTO 6 based on the operation of the PTO switch 12, and controls the operation of the relay circuit 78 based on the operation of the confirmation switch 75.

[0125] The control device 76 switches the PTO 6 to the transmission state and switches the relay circuit 78 to the connection state when a signal indicating that the PTO switch 12 has been turned on is input, and switches the relay circuit 78 to the connection state when a signal indicating that the confirmation switch 75 has been turned on is input.

[0126] In this way, in the work vehicle 1 of this embodiment, simply by turning on the confirmation switch 75, the LCD screen 71 and the power supply 13 are connected via the relay circuit 78, so there is no need to start the engine 3 once, and the LCD screen 71 can be turned on to display the status of the above-mentioned work devices.

[0127] In this embodiment, even when the PTO switch 12 is turned on, the LCD screen 71 and the power supply 13 are connected via the relay circuit 78. Therefore, even when the engine 3 is running and the working device is in operation, the LCD screen 71 can be lit up to display the status of the working device, just as in the conventional case. [Explanation of symbols]

[0128] 1 Work vehicle 3 Engine 4 Tank (work equipment) 5 Compressor (working equipment) 6 PTO (power take-off and take-off) 11 Key Switches 12 PTO switch (selector switch) 13 Power supply 71 LCD screen (panel) 75 Confirmation switch 76 Control Device 78 Relay Circuit

Claims

1. The engine and a working device operated by the driving force of the engine; A work vehicle including a drive switching device that can switch between a transmission state in which the drive force is transmitted to the work device and a disconnection state in which the transmission of the drive force to the work device is disconnected, a changeover switch for switching between a transmission state and a cutoff state of the drive switching device; a panel that displays the status of the working device; a power supply for supplying power to the panel; a relay circuit capable of switching between a connection state in which the panel and the power supply are electrically connected and a disconnection state in which the panel and the power supply are electrically disconnected; a confirmation switch for switching between a connected state and a disconnected state of the relay circuit; a control device that controls the operation of the drive switching device based on the operation of the changeover switch and that controls the operation of the relay circuit based on the operation of the confirmation switch, The control device When a signal indicating that the changeover switch has been turned on is input, the drive changeover device is switched to a transmission state, and the relay circuit is switched to a connection state; When the engine is stopped, When a signal indicating that the confirmation switch has been turned on is input, the relay circuit is switched to a connected state. A work vehicle characterized by:

2. The control device When a predetermined time has elapsed since the confirmation switch was turned on, the relay circuit is switched to a disconnected state.

2. The work vehicle according to claim 1, wherein:

3. The control device When a signal indicating that the changeover switch has been turned on is input, maintaining the relay circuit in a connected state even after the predetermined time has elapsed; 3. The work vehicle according to claim 2, wherein:

4. An engine; a working device operated by the driving force of the engine; A work vehicle including a drive switching device that can switch between a transmission state in which the drive force is transmitted to the work device and a disconnection state in which the transmission of the drive force to the work device is disconnected, a changeover switch for switching between a transmission state and a cutoff state of the drive switching device; a panel that displays the status of the working device; a power supply for supplying power to the panel; a relay circuit capable of switching between a connection state in which the panel and the power supply are electrically connected and a disconnection state in which the panel and the power supply are electrically disconnected; a confirmation switch for switching between a connected state and a disconnected state of the relay circuit; a control device that controls the operation of the drive switching device based on the operation of the changeover switch and that controls the operation of the relay circuit based on the operation of the confirmation switch, The control device When a signal indicating that the changeover switch has been turned on is input, the drive changeover device is switched to a transmission state, and the relay circuit is switched to a connection state; When a signal indicating that the confirmation switch has been turned on is input, the relay circuit is switched to a connected state, When a predetermined time has elapsed since the confirmation switch was turned on, the relay circuit is switched to a disconnected state, The confirmation switch is configured as a momentary operation switch, The control device Before the predetermined time has elapsed, When a signal indicating that the confirmation switch has been turned on is input again, switching the relay circuit to a disconnected state without waiting for the predetermined time to elapse; A work vehicle characterized by:

5. An engine; a working device operated by the driving force of the engine; A work vehicle including a drive switching device that can switch between a transmission state in which the drive force is transmitted to the work device and a disconnection state in which the transmission of the drive force to the work device is disconnected, a changeover switch for switching between a transmission state and a cutoff state of the drive switching device; a panel that displays the status of the working device; a power supply for supplying power to the panel; a relay circuit capable of switching between a connection state in which the panel and the power supply are electrically connected and a disconnection state in which the panel and the power supply are electrically disconnected; a confirmation switch for switching between a connected state and a disconnected state of the relay circuit; a control device that controls the operation of the drive switching device based on the operation of the changeover switch and that controls the operation of the relay circuit based on the operation of the confirmation switch, The control device When a signal indicating that the changeover switch has been turned on is input, the drive changeover device is switched to a transmission state, and the relay circuit is switched to a connection state; When a signal indicating that the confirmation switch has been turned on is input, the relay circuit is switched to a connected state; The work vehicle is a key switch for switching between an ON state in which the engine is in a driving state and an OFF state in which the engine is in a stopped state; The confirmation switch is configured as a momentary operation switch, The control device When a signal indicating that the key switch is in the ON state is input and a signal indicating that the drive switching device is in the disconnected state is input, the relay circuit is switched to a connected state only while a signal indicating that the confirmation switch has been turned on is being input; A work vehicle characterized by:

6. An engine; a working device operated by the driving force of the engine; A work vehicle including a drive switching device that can switch between a transmission state in which the drive force is transmitted to the work device and a disconnection state in which the transmission of the drive force to the work device is disconnected, a key switch for switching between an ON state in which the engine is in a running state and an OFF state in which the engine is in a stopped state; a changeover switch for switching between a transmission state and a cutoff state of the drive switching device; a panel that displays the status of the working device; a power supply for supplying power to the panel; a relay circuit capable of switching between a connection state in which the panel and the power supply are electrically connected and a disconnection state in which the panel and the power supply are electrically disconnected; a confirmation switch for switching between a connected state and a disconnected state of the relay circuit; a control device that controls the operation of the drive switching device based on the operation of the changeover switch and that controls the operation of the relay circuit based on the operation of the confirmation switch, The confirmation switch is The switching operation to the connected state can be performed regardless of whether the switching operation to the ON state by the key switch and the switching operation to the transmitted state by the selector switch are performed. A work vehicle characterized by:

Images