Specially-equipped vehicle

Abstract

To provide a specially-equipped vehicle capable of improving a sense of security when operating a four-way valve and improving an ease of responding to an emergency.SOLUTION: A suction vehicle 2 is equipped with a receiver tank 5, a vacuum pump 25, a four-way valve 24 that switches an air flow generated by the vacuum pump 25, a switching device 50 that switches a position of a valve body 28 of the four-way valve 24, a control device 6 that controls an operation of the vacuum pump 25 and the switching device 50, and an operation panel 15 that is located outside the vehicle and that gives instructions to the control device 6. The switching device 50 has a hydraulic cylinder 52 that performs a switching operation and an arm portion 53 that transmits a movement of the hydraulic cylinder 52 to the four-way valve 24, and the arm portion 53 has a dog 53a that indicates a position of the valve body 28, and the dog 53a indicates a plurality of designated dog positions corresponding to the respective switching positions of the valve body 28.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a specially equipped vehicle such as a suction vehicle. [Background technology]

[0002] As an example of a conventional suction vehicle, there is known a suction vehicle that sucks up sludge, earth and sand, waste liquid, etc. and collects them in a tank (see, for example, Patent Document 1). This type of suction vehicle is equipped with a pump that generates an air flow for suction, a four-way valve that switches the air flow generated by the pump, a switching device that switches the position of the valve body of the four-way valve, etc.

[0003] For example, in the suction vehicle described in Patent Document 1, a four-way valve can be remotely operated by switching the position of the valve element using an air-operated switching valve. However, when the switching valve is switched, the air supplied through the air pipe is discharged to the outside, which reduces the air in the air tank and reduces the air pressure. For this reason, the length of the air control pipe from the on-board air tank to the switching valve has been shortened to increase output and efficiency, thereby improving performance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-154822 Summary of the Invention [Problem to be solved by the invention]

[0005] In the suction trucks described above, the four-way valve and pneumatic selector valve were located in the center of the vehicle width. This resulted in poor visibility due to the piping that transmits the suction force for sucking the object to the receiver tank and the air-operated selector valve covering the four-way valve. This made maintenance of the selector valve and emergency operation difficult. In particular, the center position must be positioned halfway between the pressurized and suction positions, making visual inspection difficult and unsettling for operators. Furthermore, the piping from the onboard vacuum pump to the receiver tank and the air control piping from the onboard air tank to the selector valve had to be as short as possible for output and efficiency, limiting the flexibility of the four-way valve and selector valve placement. These issues are also a concern for special-purpose vehicles other than suction trucks (e.g., powder and granular material transport vehicles, sprinkler trucks, high-pressure washer trucks, etc.).

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a specially equipped vehicle that can improve the sense of security when operating a four-way valve and improve the ease of responding to emergencies. [Means for solving the problem]

[0007] The present invention provides a means for solving the above-mentioned problems as follows: That is, the present invention provides a specially equipped vehicle including an on-board tank for loading an object to be loaded, a pump for generating an air flow for sucking or discharging the object to or from the on-board tank, a four-way valve for switching the air flow generated by the pump, a switching device for switching the position of a valve element of the four-way valve, a control unit for controlling the operation of the pump and the switching device, and an operation panel disposed outside the vehicle for giving instructions to the control unit, wherein the switching device has a cylinder for performing a switching operation and an arm portion for transmitting the movement of the cylinder to the four-way valve, the arm portion having a dog for indicating the position of the valve element, and the dog is configured to indicate a plurality of designated dog positions corresponding to a plurality of switching positions of the valve element, respectively.

[0008] The above configuration improves the sense of security when operating the four-way valve and also improves the ease of responding to emergencies. That is, by visually checking the switching device provided near the four-way valve and confirming the designated dog position indicated by the dog on the arm, it is possible to easily recognize to which position the valve disc of the four-way valve is switched, thereby improving the sense of security when operating the four-way valve. Furthermore, in an emergency, such as when the circuit that operates the switching device fails, the operator can manually operate the arm to switch the position of the valve disc of the four-way valve, making it easy to respond to emergencies while visually checking the dog.

[0009] In the specially equipped vehicle having the above configuration, the cylinder is preferably a hydraulic cylinder that is hydraulically operated.

[0010] According to the above configuration, unlike an air-operated switching valve that discharges air to the outside when activated, a hydraulic cylinder requires a return pipe to return hydraulic oil to the oil reservoir. By using a hydraulic cylinder, it is not necessary to shorten the length of the hydraulic control pipes for output and efficiency, compared to when an air-operated switching valve is used. This allows for greater flexibility in the placement of the four-way valve and hydraulic cylinder.

[0011] In the specially equipped vehicle having the above configuration, it is preferable that the dog is installed in the same direction as the operation panel in the left-right direction of the vehicle.

[0012] According to the above configuration, the designated dog position indicated by the dog of the arm portion can be confirmed from the operating position of the operation panel, allowing the worker to work with peace of mind.

[0013] In the specially equipped vehicle having the above configuration, the control panel is provided with a dog position notification device, and a position sensor is provided to detect the dog corresponding to each of the plurality of designated dog positions, and it is preferable that the dog position notification device notifies the corresponding designated dog position when the dog is detected by the position sensor.

[0014] According to the above configuration, the operator can feel more secure by being notified by both the designated dog position indicated by the dog on the arm and the dog position notification device on the control panel. Also, compared to when the position of the four-way valve disc is notified based on the operation signal or hydraulic pressure value of the cylinder's operation control, when manually switching the four-way valve in an emergency, it is possible to prevent a contradiction from occurring between the designated dog position indicated by the dog on the arm and the dog position notification device on the control panel, so the operator can be more reliably notified of the position of the four-way valve disc.

[0015] In the specially equipped vehicle having the above configuration, it is preferable that the specially equipped vehicle is a suction vehicle, and the specified dog positions include at least a suction position, a center position, and a pressure position.

[0016] According to the above configuration, in a suction vehicle, the operator can be reliably informed of the three positions (suction position, neutral position, and pressurized position) of the valve body of the four-way valve, including the neutral position, which is of particular concern to the operator.

[0017] In the specially equipped vehicle having the above configuration, it is preferable that the arm portion is disposed near the operation panel and is detachably attached to at least one of the four-way valve and the cylinder.

[0018] According to the above configuration, in an emergency such as when a circuit that operates the switching device fails, the four-way valve can be easily switched to manual operation using the arm portion.

[0019] In the specially equipped vehicle having the above configuration, it is preferable that the cylinder be capable of being rotated from an operating position that moves the four-way valve via the arm portion and moved to a retracted position that is located outside the movable range of the arm portion.

[0020] According to the above configuration, the cylinder does not interfere with the manual operation of the four-way valve by the arm portion, and furthermore, the four-way valve can be easily restored to hydraulic operation and maintained. [Effects of the Invention]

[0021] According to the specially equipped vehicle of the present invention, it is possible to improve the sense of security when operating the four-way valve and also to improve the ease of responding to emergencies. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a left side view showing a schematic configuration of a suction vehicle according to an embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. 2 is an air piping diagram of a suction device mounted on a suction vehicle, showing the flow of air during suction. [Figure 4] FIG. 4 is a diagram showing the flow of air when pressurized in the air piping diagram of FIG. 3. [Figure 5] 10A and 10B are diagrams showing the stopping positions of the valve element of the four-way valve when switching to three modes: suction mode, pressurization mode, and neutral mode. [Figure 6] FIG. 2 is a side view showing an operation panel installed on the suction vehicle. [Figure 7] FIG. 2 is a schematic diagram showing a hydraulic circuit of a suction vehicle. [Figure 8] FIG. 2 is a schematic diagram showing a part of a sequence circuit of the suction vehicle. [Figure 9] FIG. 10 is a diagram showing the state when an operator looks up at the upper left side of the suction vehicle. [Figure 10] FIG. 2 is a side view showing a valve body switching device of a four-way valve. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention relates to a specially equipped vehicle, and more particularly to a vehicle having an on-board tank for carrying an object to be loaded, a pump for generating an air flow for sucking or discharging the object to or from the on-board tank, a four-way valve for switching the air flow generated by the pump, a switching device for switching the position of the valve body of the four-way valve, a control unit for controlling the operation of the pump and the switching device, and a control panel disposed outside the vehicle for issuing instructions to the control unit.

[0024] The following describes a case where the present invention is applied to a suction vehicle 2 as shown in Figures 1 and 2. As shown in Figures 1 and 2, a receiver tank (on-board tank) 5 and a suction device 1 for creating a negative pressure inside the receiver tank 5 to suck an object to be suctioned (an object to be loaded) into the receiver tank 5 are provided on a subframe 4 on a chassis 3 of the suction vehicle 2. Specifically, the receiver tank 5 is mounted on the rear of the subframe 4 and contains an object to be suctioned, such as sludge, earth and sand, waste liquid, etc.

[0025] The receiver tank 5 has a tank body 5a that has a circular cross-section and a rear-end opening, and a tailgate 5c that opens and closes this rear-end opening. The tailgate 5c is pivotally supported on the upper rear end of the tank body 5a via a hinge pin 5b. An opening / closing cylinder 5d is provided between the tank body 5a and the tailgate 5c, and by extending and retracting this opening / closing cylinder 5d, the tailgate 5c can open and close the rear-end opening of the tank body 5a.

[0026] A suction port 8 with an on-off valve that serves as a suction port for objects to be sucked in, and a discharge port 9 with an on-off valve that serves as a discharge port for objects to be sucked in are provided at the bottom of the tailgate 5c. The receiver tank 5 is pivotally supported on the subframe 4 so that it can tilt relative to the subframe 4 via a tilting shaft 10 provided at the rear of the subframe 4. That is, a tilting cylinder 11 is provided between the subframe 4 and the receiver tank 5. By operating the tilting cylinder 11 to extend or retract, the receiver tank 5 can be rotated upright or down around the tilting shaft 10.

[0027] When the suction vehicle 2 sucks and stores the object to be sucked into the receiver tank 5, the reduced pressure and air flow inside the receiver tank 5 causes the object to be sucked into the receiver tank 5 from the outside through a suction hose (not shown) connected to the suction port 8. On the other hand, when the suction vehicle 2 discharges the object to be sucked into the receiver tank 5 to, for example, a sludge treatment plant, the air inside the receiver tank 5 is pressurized, and the object to be sucked into the receiver tank 5 is discharged to the outside through a discharge hose (not shown) connected to the discharge port 9. It is also possible to discharge the object to be sucked into the receiver tank 5 by opening the tailgate 5c and rotating the receiver tank 5 upright.

[0028] A vacuum pump 25 is provided on the subframe 4 between the cab 13 and the receiver tank 5 to pressurize and depressurize the air in the receiver tank 5 and generate an air flow. A water-sealed pump, for example, is used as the vacuum pump 25. The vacuum pump 25 is driven and rotated by the driving force of an engine (not shown) connected via a drive shaft of the PTO (power take-off) of the suction vehicle 2. Around the vacuum pump 25, there are arranged pipes connected to the vacuum pump 25, various valves, an operation panel (control panel) 15, and the like. As shown in FIG. 9 , the operation panel 15 is installed on one side of the suction vehicle 2 in the left-right direction. In this embodiment, the operation panel 15 is provided on the left side of the suction vehicle 2.

[0029] As shown in FIG. 6, the operation panel 15 is equipped with a control device (controller) 6 that controls the operation of the vacuum pump 25 and a switching device 50 for the four-way valve 24 (described later) in the suction device 1. As shown in FIG. 5, the operation panel 15 is provided with a suction mode button 15a, a neutral mode button 15b, and a pressurization mode button 15c as operation switches for switching the valve element 28 of the four-way valve 24 to one of three modes: suction mode, neutral mode, and pressurization mode. The operation panel 15 also has an accelerator knob 15d for adjusting the rotation speed of the vacuum pump 25. The suction mode button 15a is provided with a suction indicator lamp 40a that indicates that the four-way valve 24 has been switched to the suction mode. The pressurization mode button 15c is provided with a pressurization indicator lamp 40c that indicates that the four-way valve 24 has been switched to the pressurization mode. The control device 6 may be provided in the operator's cab 13.

[0030] The operation panel 15 is also provided with an operating lever 27 for operating the opening / closing cylinder 5d and the tilting cylinder 11. Operating the operating lever 27 switches the hydraulic circuit O (described later), causing the opening / closing cylinder 5d to contract or extend, and the tilting cylinder 11 to contract or extend. In this embodiment, the single operating lever 27 can operate the opening / closing cylinder 5d and the tilting cylinder 11. The operating lever 27 can be operated left and right and up and down, for example, around the position shown in the figure. For example, when the operating lever 27 is operated upward, the tilting cylinder 11 extends, causing the receiver tank 5 to rise (dump up). When the operating lever 27 is operated downward, the tilting cylinder 11 contracts, causing the receiver tank 5 to fall (dump down). When the operating lever 27 is operated rightward, the opening / closing cylinder 5d extends, causing the tailgate 5c to open (gate open). When the operating lever 27 is operated leftward, the opening / closing cylinder 5d contracts to close the tailgate 5c (gate closed). Note that the opening / closing cylinder 5d and the tilting cylinder 11 may be operated by separate operating tools.

[0031] Next, the four-way valve 24 provided in the suction device 1 will be described. The four-way valve 24 is provided in the suction device 1 to switch the air flow generated by the vacuum pump 25. Specifically, the four-way valve 24 is used to switch between three modes: a suction mode in which the receiver tank 5 is negatively pressurized and the object to be suctioned is sucked into the receiver tank 5; a pressurization mode in which the receiver tank 5 is pressurized and the object to be suctioned is discharged out of the receiver tank 5; and a neutral mode in which the vacuum pump 25 is driven but the receiver tank 5 is not pressurized or depressurized. FIGS. 3 and 4 are diagrams showing the operating states of the suction device 1 according to this embodiment. FIG. 5 is a perspective view showing the positions of the valve element 28 of the four-way valve 24 during suction (upper left diagram), neutral (center diagram), and pressurization (upper right diagram). The ports 24a to 24d of the four-way valve 24 shown in FIG. 5 correspond to the ports 24a to 24d of the four-way valve 24 shown in FIGS. 3 and 4.

[0032] FIG. 3 illustrates the flow of air during suction by the suction device 1. As shown in FIGS. 3 and 5, during suction, ports 24a and 24b of the four-way valve 24 are connected, and ports 24c and 24d are connected. A valve element 28 separates ports 24a and 24b from ports 24c and 24d. This allows air to simultaneously flow from port 24a to port 24b and from port 24d to port 24c. Air drawn from the receiver tank 5 passes through the secondary catcher 20 and the tertiary catcher 21, which are cyclone-type dust collectors, and the four-way valve 24, then through the ejector 30 and the water-sealed pump 25, which is a vacuum pump. The air then passes through the quaternary catcher 22, the four-way valve 24, and the integrated silencer 23 to be exhausted. These components are interconnected by piping 7 (7a to 7g).

[0033] FIG. 4 is a diagram showing the air flow during pressurization of the suction device 1. As shown in FIGS. 4 and 5, during pressurization, the position of the valve element 28 of the four-way valve 24 is switched, connecting ports 24a and 24d, and connecting ports 24b and 24c. The valve element 28 separates ports 24a and 24d from ports 24b and 24c. This allows air to simultaneously flow from port 24a to port 24d and from port 24b to port 24c. As a result, air sucked from the integrated silencer 23 passes through the four-way valve 24, is sucked into the water seal pump 25, passes through the quaternary catcher 22, passes again through the four-way valve 24, and then passes through the tertiary catcher 21 and secondary catcher 20 to pressurize the receiver tank 5.

[0034] 5, during neutral operation, the valve element 28 of the four-way valve 24 remains stationary at a position halfway between the suction and pressurization states described above. The position of the valve element 28 of the four-way valve 24 is changed by an actuator integrally attached to the four-way valve 24. In this embodiment, a hydraulic cylinder 52 that is hydraulically operated is used as the actuator that switches the position of the valve element 28 of the four-way valve 24. The hydraulic cylinder 52 is provided in a switching device 50 of the four-way valve 24. Details of the switching device 50 will be described later.

[0035] Next, the hydraulic circuit O for operating the opening / closing cylinder 5d, the tilting cylinder 11, and the hydraulic cylinder 52 of the switching device 50 in the suction vehicle 2 will be described with reference to Figure 7. As shown in Figure 7, the hydraulic circuit O includes a hydraulic pump P as a hydraulic pressure source, an oil reservoir T, and a main valve unit M that houses solenoid valves V1, V2, and V3 in a common valve block. The hydraulic pump P is connected to the PTO described above, and as the rotation speed of the engine (not shown) increases, the rotation speed of the hydraulic pump P also increases, increasing the discharge amount.

[0036] The main valve unit M is disposed, for example, behind the operation panel 15, and is connected by hydraulic piping to the opening / closing cylinder 5d, the tilting cylinder 11, and the hydraulic cylinder 52. The solenoid valves V1, V2, and V3 are, for example, 6-port 3-position directional control valves, and their positions are switched by energizing the solenoids (see FIG. 8).

[0037] When the solenoid SOLa is excited by energization from the sequence circuit S (see FIG. 8), the electromagnetic valve V1 switches to the first communication position (left position in the figure) and supplies hydraulic oil from the hydraulic pump P to the rod-side oil chamber of the tilting cylinder 11. This causes the tilting cylinder 11 to contract. On the other hand, when the solenoid SOLb is excited, the electromagnetic valve V1 switches to the second communication position (right position in the figure) and supplies hydraulic oil from the hydraulic pump P to the cap-side oil chamber of the tilting cylinder 11. This causes the tilting cylinder 11 to extend.

[0038] When hydraulic oil is supplied to the cap-side oil chamber of the tilting cylinder 11 in this way, the tilting cylinder 11 extends, raising the receiver tank 5. On the other hand, when hydraulic oil is supplied to the rod-side oil chamber of the tilting cylinder 11, the tilting cylinder 11 contracts, lowering the receiver tank 5. When the solenoid valves V1, V2, and V3 are in the neutral position, the hydraulic oil returns to the oil reservoir T.

[0039] When the solenoid SOLc is excited by energization from the sequence circuit S, the electromagnetic valve V2 switches to the first communication position (left position in the figure) and supplies hydraulic oil from the hydraulic pump P to the rod-side oil chamber of the opening-closing cylinder 5d. This causes the opening-closing cylinder 5d to contract. On the other hand, when the solenoid SOLd is excited, the electromagnetic valve V2 switches to the second communication position (right position in the figure) and supplies hydraulic oil from the hydraulic pump P to the cap-side oil chamber of the opening-closing cylinder 5d. This causes the opening-closing cylinder 5d to extend.

[0040] When hydraulic oil is supplied to the cap-side oil chamber of the opening-closing cylinder 5d in this way, the opening-closing cylinder 5d extends, causing the tailgate 5c to rotate around the hinge pin 5b and opening the rear opening of the tank body 5a. On the other hand, when hydraulic oil is supplied to the rod-side oil chamber of the opening-closing cylinder 5d, the opening-closing cylinder 5d contracts, causing the tailgate 5c to rotate around the hinge pin 5b and closing the rear opening of the tank body 5a.

[0041] When the solenoid SOLe is excited by energization from the sequence circuit S, the electromagnetic valve V3 switches to a first communication position (left position in the figure) and supplies hydraulic oil from the hydraulic pump P to the rod-side oil chamber of the hydraulic cylinder 52. This causes the hydraulic cylinder 52 to contract. On the other hand, when the solenoid SOLf is excited, the electromagnetic valve V3 switches to a second communication position (right position in the figure) and supplies hydraulic oil from the hydraulic pump P to the cap-side oil chamber of the hydraulic cylinder 52. This causes the hydraulic cylinder 52 to extend.

[0042] When hydraulic oil is supplied to the cap-side oil chamber of the hydraulic cylinder 52 in this manner, the cylinder rod 52a of the hydraulic cylinder 52 extends, and the valve element 28 of the four-way valve 24 is switched toward the pressurized position. This causes a switch from neutral mode to pressurized mode, and from suction mode to neutral mode. On the other hand, when hydraulic oil is supplied to the rod-side oil chamber of the hydraulic cylinder 52, the cylinder rod 52a of the hydraulic cylinder 52 contracts, and the valve element 28 of the four-way valve 24 is switched toward the suction position. This causes a switch from neutral mode to suction mode, and from pressurized mode to neutral mode.

[0043] Next, the sequence circuit S for operating the hydraulic cylinder 52 of the switching device 50 in the suction vehicle 2 will be described with reference to Figure 8. This sequence circuit S controls the operation of the switching device 50 of the valve element 28 of the four-way valve 24, etc., and is provided in the control device 6 described above. The sequence circuit S is provided with contacts corresponding to the suction mode button 15a, neutral mode button 15b, and pressurization mode button 15c of the operation panel 15 described above, as well as solenoids SOLe and SOLf of the hydraulic circuit O described above, proximity sensors 54-57, relays R1-R4, and relay contacts r1-r8, which will be described later. Also provided are the suction indicator lamp 40a, pressurization indicator lamp 40c, etc.

[0044] As relay R1 is turned on and off, the corresponding relay contacts r1, r6, and r7 open and close. When relay R1 is turned on, relay contacts r1 and r6 close and relay contact r7 opens. On the other hand, when relay R1 is turned off, relay contacts r1 and r6 open and relay contact r7 closes. Also, as relay R2 is turned on and off, the corresponding relay contacts r2, r3, and r8 open and close. When relay R2 is turned on, relay contacts r2 and r3 close and relay contact r8 opens. On the other hand, when relay R2 is turned off, relay contacts r2 and r3 open and relay contact r8 closes.

[0045] As relay R3 is turned on and off, the corresponding relay contact r5 opens and closes. When relay R3 is turned on, relay contact r5 closes, and when relay R3 is turned off, relay contact r5 opens. Also, as relay R4 is turned on and off, the corresponding relay contact r4 opens and closes. When relay R4 is turned on, relay contact r4 opens, and when relay R4 is turned off, relay contact r4 closes.

[0046] Relay R1 is switched on when proximity sensor 54 is turned on, and is switched off when relay contact r4 is opened. Furthermore, when proximity sensor 54 is on, for example, suction in progress indicator lamp 40a provided on operation panel 15 is turned on, and when proximity sensor 54 is off, suction in progress indicator lamp 40a is turned off. Relay R2 is switched on when proximity sensor 55 is turned on, and is switched off when relay contact r4 is opened. Furthermore, when proximity sensor 55 is on, for example, pressurization in progress indicator lamp 40c provided on operation panel 15 is turned on, and when proximity sensor 55 is off, pressurization in progress indicator lamp 40c is turned off.

[0047] Relay R3 is switched on when center mode button 15b is turned on, and is switched off when relay contact r4 is opened. Relay R4 is switched on when at least one of proximity sensors 56 and 57 is on, and is switched off when both proximity sensors 56 and 57 are off.

[0048] When the neutral mode button 15b is off and the suction mode button 15a is on, the solenoid SOLe is energized while the relay contact r7 is closed. However, when the relay contact r7 opens, the solenoid SOLe is de-energized. Also, when the neutral mode button 15b is on, the solenoid SOLe is energized while the relay contact r3 is closed. However, when the relay contact r3 opens, the solenoid SOLe is de-energized. When the solenoid SOLe is energized, the solenoid valve V3 is switched to the first communication position (the left position in FIG. 7), and hydraulic oil is supplied to the rod-side oil chamber of the hydraulic cylinder 52. This causes the cylinder rod 52a of the hydraulic cylinder 52 to contract, and the valve element 28 of the four-way valve 24 is switched toward the suction position.

[0049] For example, when suction mode button 15a on operation panel 15 is turned on to switch from neutral mode to suction mode, or when neutral mode button 15b on operation panel 15 is turned on to return from pressurization mode to neutral mode, solenoid SOLe is energized and valve element 28 of four-way valve 24 is switched toward the suction position. Note that when returning from pressurization mode to neutral mode, if proximity sensors 56, 57 detect that valve element 28 of four-way valve 24 is in the neutral position, solenoid SOLe is de-energized and the supply of hydraulic oil to the rod-side oil chamber of hydraulic cylinder 52 is stopped.

[0050] On the other hand, when the neutral mode button 15b is off and the pressurizing mode button 15c is on, the solenoid SOLf is energized while the relay contact r8 is closed. However, when the relay contact r8 opens, the solenoid SOLf is de-energized. Also, when the neutral mode button 15b is on, the solenoid SOLf is energized while the relay contact r6 is closed. However, when the relay contact r6 opens, the solenoid SOLf is de-energized. When the solenoid SOLf is energized, the solenoid valve V3 is switched to the second communicating position (the right-hand position in FIG. 7), and hydraulic oil is supplied to the cap-side oil chamber of the hydraulic cylinder 52. This causes the cylinder rod 52a of the hydraulic cylinder 52 to extend, and the valve element 28 of the four-way valve 24 is switched toward the pressurizing position.

[0051] For example, when the pressurization mode button 15c on the operation panel 15 is turned on to switch from the neutral mode to the pressurization mode, or when the neutral mode button 15b on the operation panel 15 is turned on to return from the suction mode to the neutral mode, the solenoid SOLf is energized and the valve element 28 of the four-way valve 24 is switched toward the pressurization position. When returning from the suction mode to the neutral mode, if the proximity sensors 56, 57 detect that the valve element 28 of the four-way valve 24 is in the neutral position, the solenoid SOLf is de-energized and the supply of hydraulic oil to the cap-side oil chamber of the hydraulic cylinder 52 is stopped.

[0052] In this embodiment, as described above, the suction vehicle 2 includes a receiver tank 5 for storing objects to be suctioned, a vacuum pump 25 for generating an air flow to suck or discharge objects to or from the receiver tank 5, a four-way valve 24 for switching the air flow generated by the vacuum pump 25, a switching device 50 for switching the position of the valve element 28 of the four-way valve 24, a control device 6 for controlling the operation of the vacuum pump 25 and the switching device 50, and an operation panel 15 located outside the vehicle for issuing instructions to the control device 6. In the suction vehicle 2 configured as described above, the switching device 50 includes a hydraulic cylinder 52 for performing the switching operation and an arm 53 for transmitting the movement of the hydraulic cylinder 52 to the four-way valve 24. The arm 53 has a dog 53a for indicating the position of the valve element 28, and the dog 53a is configured to indicate multiple designated dog positions corresponding to the multiple switching positions of the valve element 28. This point will be described below with reference to Figures 9, 10, etc.

[0053] As shown in Figures 9 and 10, the switching device 50 is attached to the side of the four-way valve 24. The switching device 50 has a hydraulic cylinder 52 that performs the switching operation and an arm portion 53 that transmits the movement of the hydraulic cylinder 52 to the four-way valve 24. The hydraulic cylinder 52 is fixed with bolts or the like to a mounting plate 51 attached to the side of the four-way valve 24. The hydraulic cylinder 52 is arranged so that its cylinder rod 52a extends and retracts in the vertical direction. The end portion (the right end portion in Figure 10) of the arm portion 53 is rotatably connected to a rotating shaft 52b provided at the tip of the cylinder rod 52a of the hydraulic cylinder 52. The center portion 53b of the arm portion 53 is connected to the valve shaft of the valve disc 28 of the four-way valve 24. When the arm portion 53 is operated, the valve disc 28 of the four-way valve 24 rotates around the valve shaft.

[0054] More specifically, when the cylinder rod 52a of the hydraulic cylinder 52 is extended, the arm portion 53 rotates counterclockwise around the rotation shaft 52b, and the valve element 28 of the four-way valve 24 also rotates in the same direction. As a result, the valve element 28 of the four-way valve 24 is switched toward the pressurizing position. On the other hand, when the cylinder rod 52a of the hydraulic cylinder 52 is contracted, the arm portion 53 rotates clockwise around the rotation shaft 52b, and the valve element 28 of the four-way valve 24 also rotates in the same direction. As a result, the valve element 28 of the four-way valve 24 is switched toward the suction position.

[0055] The arm 53 has a dog 53a that indicates the position of the valve disc 28 of the four-way valve 24. In this embodiment, the tip of the arm 53 (the left end in FIG. 10) is the dog 53a, and the position indicated by the dog 53a is changed by the arm 53 rotating about the rotation shaft 52b. The dog 53a is configured to indicate a plurality of designated dog positions corresponding to the plurality of switching positions of the valve disc 28 of the four-way valve 24. Specifically, when the valve disc 28 of the four-way valve 24 is switched to the neutral position (see the center diagram in FIG. 5), the dog 53a of the arm 53 stops at a position indicating a predetermined position corresponding to the neutral position of the valve disc 28. In this case, the dog 53a of the arm portion 53 stops at a third designated position P3 oriented substantially horizontally. The mounting plate 51 is provided with a proximity sensor 56 for detecting whether the dog 53a of the arm portion 53 is at the third designated position P3. The mounting plate 51 is also provided with a proximity sensor 57 for detecting the distal end of the arm portion 53 when the dog 53a of the arm portion 53 is at the third designated position P3. The proximity sensor 57 is provided on the opposite side of the central portion 53b of the arm portion 53 from the proximity sensor 56. The two proximity sensors 56, 57 are configured to detect whether the dog 53a of the arm portion 53 is at the third designated position P3.

[0056] Furthermore, when the cylinder rod 52a of the hydraulic cylinder 52 is extended and the valve element 28 of the four-way valve 24 is switched to the pressurized position (see the upper right diagram in FIG. 5), the dog 53a of the arm portion 53 stops at a position indicating a predetermined position corresponding to the pressurized position of the valve element 28. In this case, the dog 53a of the arm portion 53 stops at a second designated position P2 facing diagonally downward from the approximately horizontal direction. The mounting plate 51 is provided with a proximity sensor 55 that detects that the dog 53a of the arm portion 53 is at the second designated position P2.

[0057] On the other hand, when the cylinder rod 52a of the hydraulic cylinder 52 contracts and the valve element 28 of the four-way valve 24 is switched to the suction position (see the upper left diagram in FIG. 5), the dog 53a of the arm portion 53 stops at a position indicating a predetermined position corresponding to the suction position of the valve element 28. In this case, the dog 53a of the arm portion 53 stops at a first designated position P1 facing diagonally upward from the approximately horizontal direction. The mounting plate 51 is provided with a proximity sensor 54 that detects that the dog 53a of the arm portion 53 is at the first designated position P1.

[0058] In this embodiment, the dog 53a of the arm portion 53 indicates the first to third designated positions P1 to P3 corresponding to the multiple switching positions of the valve disc 28 of the four-way valve 24, thereby improving the sense of security in operating the four-way valve 24 and improving the ease of emergency response. That is, by visually checking the switching device 50 provided near the four-way valve 24 and confirming the designated dog positions indicated by the dog 53a of the arm portion 53, it is possible to easily recognize to which position the valve disc 28 of the four-way valve 24 is switched: the pressurized position, the neutral position, or the suction position. Specifically, by visually confirming that the dog 53a of the arm portion 53 is in the first designated position P1, it is possible to determine that the valve disc 28 of the four-way valve 24 is in the suction position. By visually confirming that the dog 53a of the arm portion 53 is in the second designated position P2, it is possible to determine that the valve disc 28 of the four-way valve 24 is in the pressurized position. By visually confirming that the dog 53a of the arm portion 53 is in the third designated position P3, it can be seen that the valve element 28 of the four-way valve 24 is in the neutral position. This improves the sense of security when operating the four-way valve 24. Furthermore, in an emergency, such as when the hydraulic circuit O that operates the switching device 50 fails, the operator can manually operate the arm portion 53 to switch the position of the valve element 28 of the four-way valve 24, making it easy to respond to an emergency while visually checking the dog 53a.

[0059] Furthermore, because the hydraulic cylinder 52 is used as the actuator for switching the position of the valve element 28 of the four-way valve 24, a return pipe is provided to return the hydraulic oil to the oil reservoir T, unlike an air-type switching valve that discharges air to the outside when activated. In this way, by using the hydraulic cylinder 52, it is not necessary to shorten the length of the hydraulic control pipe for the sake of output and efficiency, compared to when an air-type switching valve is used. This allows for greater freedom in the placement of the four-way valve 24 and the hydraulic cylinder 52.

[0060] In this embodiment, as shown in FIG. 9, the dog 53a of the arm unit 53 is installed facing the same direction as the operation panel 15 in the left-right direction of the vehicle. The operation panel 15 is provided on the left side of the suction vehicle 2, so that an operator standing to the left of the suction vehicle 2 can operate the operation panel 15. The switching device 50 is installed on the left side of the four-way valve 24, so that an operator standing to the left of the suction vehicle 2 can visually observe the dog 53a of the arm unit 53. FIG. 9 shows the state when an operator standing to the left of the suction vehicle 2 looks up at the top of the suction device 1. In FIG. 9, the entire switching device 50 (mounting plate 51) can be seen below the piping 7b. On the other hand, when the suction device 1 is viewed from the side, as shown in FIG. 1, the piping 7b overlaps the top of the switching device 50 (mounting plate 51), so that the top of the switching device 50 (mounting plate 51) is not visible. As shown in Figure 9, it is preferable that the entire switching device 50 (mounting plate 51) is visible, but it is not necessary that the entire switching device 50 (mounting plate 51) is visible; it is sufficient that the switching device 50 (mounting plate 51) is provided in a position where at least the dog 53a and the first to third designated positions P1 to P3 indicated by the dog 53a are visible.

[0061] In this embodiment, an operator standing to the left of the suction vehicle 2 can see the entire switching device 50 (mounting plate 51), and can confirm the designated dog position indicated by the dog 53a of the arm portion 53 from the operating position of the operation panel 15, allowing the operator to work with peace of mind. The mounting plate 51 may be covered with a transparent plate to protect it from wind, rain, and dirt. Alternatively, the mounting plate 51 may be covered with a steel plate during normal driving or standby, and the steel plate may be removable when necessary for work or maintenance. Alternatively, the mounting plate 51 may be covered with a steel plate, and an opening may be formed in a predetermined location in the steel plate so that only the dog 53a portion is visible.

[0062] Further, proximity sensors (position sensors) 54-57 are provided to detect the dog 53a of the arm portion 53 corresponding to the first to third designated positions P1-P3, respectively. The operation panel 15 is provided with a suction indicator lamp 40a and a pressurization indicator lamp 40c that indicate the corresponding first and second designated positions P1, P2 when the dog 53a of the arm portion 53 is detected by the proximity sensors 54, 55. By providing notification of the first to third designated positions P1-P3 indicated by the dog 53a of the arm portion 53 and the suction indicator lamp 40a and the pressurization indicator lamp 40c on the operation panel 15, the operator can feel more secure. In the suction vehicle 2, the operator can be reliably informed of the three positions (suction position, neutral position, and pressurization position) of the valve element 28 of the four-way valve 24, including the neutral position, which is of particular concern to the operator. Furthermore, compared to when the position of the valve body 28 of the four-way valve 24 is notified based on the operation signal or hydraulic pressure value of the hydraulic cylinder 52 for controlling the operation, when the four-way valve 24 is manually switched in an emergency, no inconsistent state can be generated between the first to third designated positions P1 to P3 indicated by the dog 53a of the arm portion 53 and the suction indicator lamp 40a and pressurization indicator lamp 40c on the operation panel 15, so the position of the valve body 28 of the four-way valve 24 can be more reliably notified to the operator.

[0063] In this embodiment, the arm unit 53 is disposed near the operation panel 15 and is removably attached to the tip of the cylinder rod 52a of the hydraulic cylinder 52. This allows for easy switching to manual operation of the four-way valve 24 using the arm unit 53 in an emergency, such as when the hydraulic circuit O that operates the switching device 50 fails. In other words, by removing the arm unit 53 from the cylinder rod 52a of the hydraulic cylinder 52, the four-way valve 24 can be easily operated manually via the arm unit 53. The arm unit 53 is also removably attached to the four-way valve 24. In an emergency, the arm unit 53 can be removed from the four-way valve 24 and a handle attached, allowing for easy manual operation of the four-way valve 24. Note that the arm unit 53 may be removably attached to only one of the hydraulic cylinder 52 and the four-way valve 24.

[0064] Furthermore, the hydraulic cylinder 52 can be rotated via the arm portion 53 from an operating position (position shown by a solid line in FIG. 10) that moves the four-way valve 24 to a retracted position (position shown by a two-dot chain line in FIG. 10) that is located outside the movable range of the arm portion 53. As a result, in an emergency, by detaching the arm portion 53 from the cylinder rod 52a of the hydraulic cylinder 52 and rotating the hydraulic cylinder 52 about the rotation shaft 52c to move it to the retracted position, the hydraulic cylinder 52 will no longer interfere with manual operation of the four-way valve 24 by the arm portion 53, and further, restoration of hydraulic operation of the four-way valve 24 and maintenance can be easily performed.

[0065] The embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. The technical scope of the present invention is not interpreted solely by the above-described embodiments, but is defined by the claims. The technical scope of the present invention also includes all modifications within the meaning and scope of the claims.

[0066] In the above embodiment, proximity sensors 54 to 57 are used as position sensors, but non-contact sensors other than proximity sensors may be used, or contact sensors such as limit switches may be used. Also, while two proximity sensors 56 and 57 are used to reliably detect the center position of the valve element 28 of the four-way valve 24, only proximity sensor 56 may be used.

[0067] In the above embodiment, the hydraulic cylinder 52 is controlled by a sequence circuit S controlled by a relay to control the position of the valve element 28 of the four-way valve 24. However, the present invention is not limited to this, and the hydraulic cylinder 52 may be controlled by a programmable logic controller (PLC) controlled by a program to control the position of the valve element 28 of the four-way valve 24.

[0068] In the suction vehicle of the above embodiment, the vacuum pump 25 is a water-sealed pump, but it is not limited to this and may be a vane pump or a roots blower type, or may be a type that creates a vacuum inside the receiver tank 5 and then sucks it all out at once (for example, a sanitary vehicle or a sludge suction vehicle).

[0069] The configurations of the hydraulic cylinder 52, arm portion 53, dog 53a, and first to third designated positions P1 to P3 of the mounting plate 51 of the switching device 50 described above are examples and can be changed in various ways. In the above embodiment, the hydraulic cylinder 52 is used as the actuator that switches the position of the valve element 28 of the four-way valve 24, but this is not limiting and an electric cylinder may also be used.

[0070] In the above embodiment, the present invention has been described as being applied to a suction truck, but it is not limited to this and can also be applied to other special vehicles (e.g., powder and granular material transport vehicles, sprinkler trucks, high-pressure cleaning vehicles, etc.) that have a four-way valve and its switching device. [Explanation of symbols]

[0071] 1 Suction device 2 Suction vehicle (specially equipped vehicle) 5 Receiver tank (vehicle tank) 6 Control device (control unit) 15 Operation panel (operation panel) 24 Four-way valve 25 Vacuum pump (pump) 40a Suction indicator lamp (dog position indicator) 40c Pressurizing indicator lamp (dog position alarm device) 50 Switching device 52 Hydraulic cylinder (cylinder) 53 Arm section 53a Dog 54~57 Proximity sensors (position sensors) P1~P3 1st~3rd designated position (designated dog position)

Claims

1. A specially equipped vehicle comprising: an on-board tank for loading an object to be loaded; a pump for generating an air flow for sucking or discharging the object to be loaded into the on-board tank; a four-way valve for switching the air flow by the pump; a switching device for switching the position of a valve body of the four-way valve; a control unit for controlling the operation of the pump and the switching device; and an operation panel disposed outside the vehicle for giving instructions to the control unit, The switching device has a cylinder that performs a switching operation and an arm that transmits the movement of the cylinder to the four-way valve, The arm portion has a dog that indicates the position of the valve body, and the dog is configured to indicate a plurality of designated dog positions that correspond to each of a plurality of switching positions of the valve body.

2. The specially equipped vehicle according to claim 1, The cylinder is a hydraulic cylinder that is hydraulically operated.

3. The specially equipped vehicle according to claim 2, The dog is installed in the same left-right direction as the control panel.

4. The specially equipped vehicle according to claim 3, The operation panel is provided with a dog position notification device, a position sensor is provided to detect the dog corresponding to each of the plurality of designated dog positions, and the dog position notification device notifies the corresponding designated dog position when the position sensor detects the dog.

5. The specially equipped vehicle according to claim 4, The specially equipped vehicle is a suction vehicle, The specially equipped vehicle is characterized in that the designated dog positions include at least a suction position, a center position, and a pressure position.

6. The specially equipped vehicle according to any one of claims 1 to 5, The arm portion is disposed near the control panel and is detachably attached to at least one of the four-way valve and the cylinder.

7. The specially equipped vehicle according to claim 6, The cylinder is capable of being rotated from an operating position that moves the four-way valve via the arm portion and moved to a retracted position that is located outside the movable range of the arm portion.

Images