JPS60191841A - Cargo box tilting mechanism in dump truck - Google Patents

Abstract

PURPOSE:To prevent a dump truck from being subjected to an accident such as, for example, rolling down rearward upon unloading work for loaded cargo materials, by providing a control valve which may inhibit a cargo box from tilting when a tail gate is not fully opened. CONSTITUTION:In a dump truck in which a tail gate that is opened upward by means of an auxiliary cylinder 4 is provided in the rear section of a cargo box which is rotated about the rear section of a vehicle body by means of a main cylinder 2, manually operated selector valves 8, 9 control the supply and discharge of hydraulic oil for both cylinders 2, 4. An electrical circuit for a limit switch 14 for detecting the fully opened condition of the tail gate, which is provided to the cargo box, is connected with a rotary solenoid 16. Further, the solenoid selector valve 21 is changed over from a position C to a position D when the solenoid 16 is energized, and therefore, a directional selector valve 22 is held at a position A, thereby it is possible to feed hydraulic oil into a cylinder chamber 2a in the main cylinder 2 so that the damping operation of the dump car may be made.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cargo box tilting device in a dump truck,
More specifically, the present invention relates to a cargo box tilting device for a dump trunk in which a tailgate that is opened and closed by an auxiliary cylinder is provided at the rear of a cargo box that is tilted by a main cylinder. This is used in the field of ensuring the safety of unloading work by preventing the vehicle body from rolling backwards due to the shift of the center of gravity of the loaded object when unloading the cargo box by tilting it.

[Prior art]

As shown in Figure 1, a dump truck that unloads a loaded object toward the rear of the vehicle body by tilting the cargo box has a main cylinder 2 that tilts the cargo box 1 around the rear of the vehicle body; Some vehicles are equipped with a tailgate 3 that looks up at the rear, and an auxiliary cylinder 4 that opens and closes the tailgate 3. These cylinders 2.4 are designed to expand and contract by supplying and discharging hydraulic oil supplied by a hydraulic pump (not shown), but each manual switching valve for supplying and discharging hydraulic oil is independently provided in the hydraulic circuit. It is being By the way, these manual switching valves simply supply and discharge hydraulic oil independently, so in the conventional hydraulic circuit for the ij box tilting device, one cylinder does not expand or contract regardless of the state of the other cylinder. However, in order to ensure work safety, during normal unloading of 1ffl, the driver operates one manual switching valve to extend the auxiliary cylinder 4 and close the tailgate 3 as indicated by the broken line. After opening as shown, the other manual switching valve is operated to extend the main cylinder 2, and the cargo box 1 is tilted as shown by the two-dot chain line.

With such a cargo box tilting device, the cargo box can be tilted without opening the tailgate, so if the driver accidentally performs such an operation, the tailgate will prevent the cargo from sliding inside the cargo box. The cargo will remain intact. At this time, as the inclination angle of the cargo box increases, the center of gravity of the loaded object moves rearward, so if the loaded weight is large, the balance of the vehicle body may be lost, causing the front wheels to lift off the ground, or in severe cases, the vehicle body may roll backwards. There is a problem that can lead to an extremely dangerous situation. Additionally, the driver can determine whether the tailgate is open by visually confirming that the tailgate is open through the window behind the seat, or by looking at the position of the operating lever of the manual switching valve. However, since unloading work in a dump trunk is usually carried out by the driver alone, there are cases where the driver may overlook the position of the operating lever, or the tailgate may be hidden behind the load, or the driver may not be able to see the cargo box. (When you start moving the lid, it becomes impossible to observe from the window behind you, and you may not be aware of closing the tailgate 1~. Therefore, avoid situations such as rolling backwards as described above. Therefore, it is desirable that the tailgate always be open when tilting the cargo box, and there is a demand for such a cargo box tilting device.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned needs, and its purpose is to prevent the loading box from being tilted while the tailgate 1 is not fully opened during unloading work of a dump truck. An object of the present invention is to provide a cargo box tilting device for a dump truck, which can prevent accidents such as backward rollover.

[Structure of the invention]

The features of the present invention will be explained below based on the drawings. At the rear of the cargo box 1 which is tilted by the main cylinder 2 around the rear of the vehicle body, tailgates 1 and 3 are provided with an earthen floor by the auxiliary cylinder 4, and these cylinders 2.4
A dump truck is equipped with manual switching valves 8.9 for independently supplying hydraulic oil to υ1-,
A mint switch 14 detects the fully open state of the tailgate 3, a solenoid 16 is energized via this limit switch 14, and when this solenoid 16 is energized, it is possible to tilt the cargo box 1 while JJIIJviPl is activated. For example, a cargo box tilting device for a dump truck is provided with at least a control valve 20 that disables lifting of the cargo box 1.

〔Example〕

Hereinafter, the present invention will be explained in detail based on examples thereof.

Fig. 2 is an enlarged view of the rear of the cargo box 1 of a dump truck to which the cargo box tilting device of the present invention is applied. reference)
It is now tilted. A tailgate 3 is provided on the rear surface of this box 1 and is partitioned by auxiliary cylinders 4, one each on the left and right sides, which are housed in the side panels 1a of the cargo box. Operating levers 1ia and 9a of manual switching valves 8.9 for independently supplying and discharging hydraulic oil to and from the cylinders 2 and 4 are installed at a driver's seat (not shown). The tailgate 3 shown in FIG. 2 is an upward-opening type in which the opening/closing center 10 is near the top surface of the cargo box l, and if it is of this type, there is no problem even if the arm 11 shown in the figure does not exist. . For example, a protrusion 13 is mounted on the rotating base 12 of the tailgate 3, and when the tailgates 1 and 3 are rotated to the fully open state as shown by the two-dot chain line and as shown in the solid line, Limit switches 14 and 15 are installed in the cargo box l, which are activated when the box is fully closed. The electric circuit of one limit switch 14 is provided with a solenoid 16 which is energized and excited by the limit switch 14, as shown in FIG. 18 are also provided. The circuit of the other limit switch 15 is provided with a lamp 19 that lights up when the protrusion 13 moves away from the limit switch 15.
I'm getting fucked. This lamp 19 is installed in the driver's seat (not shown) together with the aforementioned lamp 17 and buzzer 18, so that the driver operating the cargo box tilting device can know the status of the tailgates 1 and 3. There is. By the way, in the hydraulic circuit of the cargo box tilting device that drives the main cylinder 2 and the auxiliary cylinder 4, when the aforementioned solenoid 16 is energized, the cargo box 1 can be tilted, but if it is not energized, the cargo box 1 can be tilted. and 4) a control that disables the raising operation, /j20
is mediated. In this example, the control valve 20 is composed of an electromagnetic switching valve 21 operated by a solenoid 16, and a directional switching valve 22 that cooperates with the electromagnetic switching valve 21. This directional switching valve 22, manual switching valve 8 and main cylinder 2
It is provided in an oil passage between the oil passage and the cylinder chamber 2a, and its position can be changed by receiving pilot pressure introduced from a pilot pressure introduction bow 1-37a of the oil passage.

The electromagnetic switching valve 21 described above has a function of selecting whether or not to switch the position of the directional switching valve 22.
By maintaining position C when the solenoid 16 is not energized, the position of the directional control valve 22 is switched from A to B using pilot pressure against its pull 22a, and when it is energized, it is switched to position D to change the direction. This is to maintain the position of the valve 22 at eight. In addition, in Figure 2, the lower part of the tailgate 3 is shown as the loading box 1.
A lashing mechanism 24 is attached for fixing to.

This is provided to prevent the tailgates 1 and 3 from opening due to loaded objects, and consists of a pin 25 at the bottom of the tailgate 3 and a hook 26 that is supported on the cargo box 1 and engages with this pin 25. It consists of a locking/disengaging portion 27, link portions 28, 29 for swinging the hook 26, and the like. In this example, the link portion 29 of the securing mechanism 24 is linked to the expansion and contraction operation of the auxiliary cylinder 4 that opens and closes the tailgate 3. That is, as described later, the auxiliary cylinder 4
starts to extend, tailgate 3 opens (Fun'/2
6 is disengaged from L" 25, and this tailgain 1.
3 is released, and the tailgate 3 is opened by the auxiliary cylinder 4, which extends further. Conversely, when the auxiliary cylinder 4 is contracted and the tailgates 1 and 3 are closed, the auxiliary cylinder 4 is further contracted and the engagement portion 2 is closed.
The engagement at 7 is made, and the tailgate 3 is secured. In conjunction with the operation of the lashing mechanism 24, in this example, a limit switch 31 is installed that comes into contact with a bracket 3o that is supported on the cargo box 1 and rotates as the auxiliary cylinder 4 expands and contracts. It is now possible to detect the release of the lashing. The circuit of this limit switch 31 includes a Bragaso l-30.
Lamp 3 that lights up when it leaves the limit switch 31
2 is provided in the driver's seat, similar to the lamps 17 and 19 described above.

According to the configuration described above, the cargo box 1 can be tilted in the following manner, and the cargo box extension movement is prevented when the tailgate 3 is not in the fully open state.

As shown by the solid line in FIG.
is in the neutral position as shown in FIG. 3, and the main cylinder 2 and the auxiliary cylinder 4 are in a contracted state. Therefore, the tailgate 3 closes off the rear part of the cargo box 1 which is in a horizontal state as shown by the solid line in FIG. Further, at the lower part of the tailgate 3, a lashing mechanism 24 prevents the tailgate 3 from opening, thereby preventing the cargo from spilling out. In this state, the rimiso I switch 14 is not in contact with the protrusion 13, so it is not energized, and the lamp 17 remains off and the buzzer 18 also sounds.
6 is also not excited.

As a result, the electromagnetic switching valve 21 of the control valve 20 maintains position C as shown in FIG. 3, and the directional switching valve 22 is at position 8 due to the spring 22a. In addition, the limit switches 15 and 31 are in contact with the protrusion 13 and the bracket 30 and are not energized, so the lamp 19.3
2 remains off.

The following describes a case where the vehicle stops and unloads cargo in a situation like this. Now, the driver accidentally tilts the main cylinder without fully opening the tailgates 1 to 3, in other words, even though the lamps 17, 19, and 32 are off and the cargo box 1 should not be tilted. Assume that the operating lever 8a of the manual switching valve 8, which commands the operation of step 2, is pushed in. Since the switching valve 8 is switched from neutral to position E, the hydraulic oil supplied by the hydraulic pump 35 is transferred to the cylinder chamber of the main cylinder 2 via the oil passage 36, the position A of the directional switching valve 22, and the oil passage 37. This leads to 2a. At the same time, the hydraulic pressure in the oil passage 37 is led out from the pilot pressure introducing boat 37a as pilot pressure from the oil passage 38 to the electromagnetic switching valve 21, and is introduced into the directional switching valve 22 via the position C1 oil passage 39. When the oil pressure in the cylinder chamber 2a increases to a certain extent, although it is not enough to tilt the cargo box 1, the pilot pressure also increases to a similar level, so that the spool of the directional control valve 22, which is no longer able to resist the pressure, is pushed back by the spring 22a. It moves against the force, and the directional control valve 22 is switched to position B. As a result, the hydraulic oil from the oil passage 36 is drained from position B to the oil tank 41 via the oil passage 40, the supply of hydraulic oil to the main cylinder 2 is stopped, and the main cylinder 2 tilts the cargo box 1. -Does not demonstrate the ability to use. When the pilot pressure drops due to drain, the directional control valve 22
returns to position 8, but when the pressure in the oil passage 37 reaches the above-mentioned pressure, it returns to position B again.

While this operation is repeated, the cylinder chamber 2
The tilting of the cargo box 1 is prevented without any further increase in the pressure at a. Therefore, unless the tailgate 3 is fully open, the cargo box 1 will not start tilting.

In this way, if the tailgate 3 is not fully opened, the cargo box l will not tilt. Therefore, when unloading the cargo, the driver must first open the tailgate 3 by moving the manual switching valve 9 from neutral to position G using the operating lever 9a. Switch. The hydraulic oil supplied by the hydraulic pump 35 is supplied from the oil passage 42 to the cylinder chambers 4a of the two auxiliary cylinders 4, and the cylinder rods 4b thereof tend to extend as shown by the two-dot chain line in FIG. However, since the lower portions of the tailgates 1 to 3 are fixed by the lashing mechanism 24, the rotation base 12 will not rotate even if the cylinder rod 4b attached to the rotation base 12 of the tailgate 3 extends. There isn't. Therefore, the cylinder main body 4c moves to the left as shown by the two-dot chain line due to the reaction force. Zunawaji, auxiliary cylinder 4
is supported by one layer of the bracket 30 which is supported on the cargo box 1, so its support point 43 rotates in the direction of arrow 45 about the shaft support point 44 of the bracket 3o. In the first case,
Since the arm 46 of the link part 29 that rotates integrally with the bracket 30 also rotates in the same direction, the hell crank 47 attached to it pushes down the rod 48 in the direction of arrow 50. This movement is transmitted to the engaging and disengaging portion 2 via the link portion 28.
7, the hook 26 is rotated about the support point 51 in the direction of arrow 52 and removed from the pin 25, and the tailgate 3 is unlocked. As the bracket 30 rotated in order to operate the securing mechanism 24 is separated from the limit switch 31, the lamp 32 circuit becomes energized and the lamp 32 in the driver's seat lights up. The driver can confirm that the tailgate 3 has been unlocked by lighting the door. Therefore, if this lamp 32 does not light up even though the manual switching valve 9 is operated once, it is clear that the tails 1 and 3 are kept locked for some reason, so the manual switching valve 9 or the state of the cargo box 1. When the tailgate 3 is released in this way, the auxiliary cylinder 4, which continues to extend, allows the The rotation of the cylinder rod 4b is prevented by the stopper 53 fixed to the cargo box 1. Therefore, the reaction force necessary for further extension of the auxiliary cylinder 4 is received by the stopper 53, so that the rotation of the cylinder rod 4b is prevented by the extension of the cylinder rod 4b. The rotating bases 12 of the tails 1 and 3 are rotated in the direction of arrow 54.The protrusion 13 of the rotating base I2, which has started rotating in this manner, separates from the limit switch 15, so the circuit of the lamp 19 becomes energized and the operation starts. The lamp 19 inside the seat lights up. This lighting allows the driver to confirm that the tailgate 3 has started to open. Note that this lamp 19 and the above-mentioned lamp 32 are not absolutely necessary. It is convenient for the driver to know that there is some type of interference or operation error if the lamp that should be lit is out.When the auxiliary cylinder 4 is extended and the tellurium gate 3 is fully open, the rotating base The protrusion 13 of 12 comes into contact with the limit switch 14. Then, the circuit becomes energized and the solenoid 16
is excited, the lamp 17 lights up and the buzzer 18 sounds. In this way, by lighting all the lamps and sounding the buzzer, the driver can release the operating lever 9a of the manual switching valve 9 to stop the extension of the auxiliary cylinder 4, and can also raise the cargo box 1. This can be confirmed. Since the manual switching valve 9 returns to neutral from position G,
Discharging of the Takedoura supplied to the cylinder chamber 4a of the auxiliary cylinder 4 is prevented, and the tailgate 3 is maintained in the fully open state. At this time, due to the excitation of the solenoid 16, the spool of the electromagnetic switching valve 21 of the control valve 20 in the hydraulic circuit moves against the spring 21a, and the position is switched from C to D. When the driver uses the operating lever 83 to switch the manual switching valve 8 from neutral to position E, hydraulic oil flows through the oil passage 36, the directional switching valve 22 at position A,
It reaches the cylinder chamber 2a of the main cylinder 2 via the oil passage 37. At the same time, the hydraulic pressure in the oil passage 37 is led out from the oil passage 38 to the electromagnetic switching valve 21 as pilot pressure, but this pilot pressure is prevented from flowing by the discharge stop 56 of the electromagnetic switching valve 21 in position D. be done. On the other hand, the hydraulic oil in the oil passage 39 is led out to the oil passage 55 via the bopanochon D, and is drained into the oil tank 41.

As a result, no force acts on the directional control valve 22 to change its position, and position A is maintained. Therefore, the supply of hydraulic oil to the cylinder chamber 2a of the main cylinder 2 continues, and the cargo box 1 is tilted by the extension of the cylinder rod 2b. At this time, the hydraulic oil in the piston chamber 2c is drained via the oil passage 57. The cargo box 1 tilted in this manner allows the loaded material to slide down without being obstructed by the tailgate 3, and unloading proceeds smoothly. Therefore, since the loaded items are not stuck in the cargo box 1 by the tailgates 1 to 3, it is possible to avoid dangerous situations such as the vehicle body rolling backwards due to the shift of the center of gravity of the loaded items.

In addition, when lowering the cargo box 1, the manual switching valve 8 is switched to position F by pulling the operating lever 8-3 of the manual switching valve 8. The working oil pressure in the main cylinder 2 becomes atmospheric pressure and is drained into the oil tank 41 via the oil path 37, position A of the directional control valve 22, and the oil path 36, and the cargo box I is lowered to its original position by its own weight. come. At this time, each time pressure acts on the pylon I/pressure introduction port 1-37a of the oil passage 37. However, since the pressure has also decreased, even if the tailgates 1 and 3 start to close and are not fully open, and as a result, the electromagnetic switching valve 21 returns to position C and tees, the directional switching valve 22 Since the position is never switched to B, the drainage of hydraulic oil is not obstructed. Therefore, in this example, the cargo box 1 can be lowered regardless of whether the tailgate 3 is opened or closed.

By the way, when the manual switching valve 9 is set to position H, the auxiliary cylinder 4 is contracted, and the tailgate 3 is closed.
As the solenoid 16 is extinguished, the lamp I
7 goes out and the buzzer 18 stops emitting and protruding. When the tailgate 3 is completely closed, the protrusion 13 of the rotating base 12 comes into contact with the limit switch 15, and the lamp 19 is turned off. When the tailgate 3 is completely closed, the auxiliary cylinder 4 is contracted, and the flasher 30 returns to the original position shown in FIG. 2 and comes into contact with the limit switch 31, and the lamp 32 is also turned off. At this time, the hell crank 47 also rotates via the arm 46, so the iron 48 is pulled up, the hook 26 of the locking/disengaging portion 27 engages with the pin 25, and the tailgate 3 is secured.

〔Effect of the invention〕

As can be seen from the detailed description of the embodiments described above, the present invention makes it possible to tilt a cargo box by detecting the fully open state of the tailgate or by using a solenoid that is energized by a mint switch. Since a control valve is provided that disables at least the lifting operation of the cargo box, the sole gate must be fully opened when tilting or tilting the cargo box for unloading. Therefore, the cargo in the tilting box will not be blocked by the wheels, and by sliding down, the balance of the car body will be maintained, causing the front wheels to lift off the ground and the car body to roll backwards. It is possible to avoid extremely dangerous situations such as

[Brief explanation of the drawing]

Fig. 1 is an overall schematic diagram of a dump truck, Fig. 2 is an enlarged view of the main parts of a cargo box equipped with the cargo box tilting device of the present invention, and Fig. 3 is a diagram of the hydraulic and electric circuits that operate the cargo box tilting device. 1
This is an example. 1-Logging box, 2-Main cylinder, 3-Tailgate, 4-Auxiliary cylinder, 8.9-Manual switching valve, 14-Limit switch, 16-Solenoid, 20-Control valve Patent applicant Kyokuto Kaihatsu Kogyo Co., Ltd.

Claims (1)

[Claims] (1) A main cylinder that tilts around the rear of the vehicle; A tenil gate that opens upwards using an auxiliary cylinder is provided at the rear of the gas box, and hydraulic oil is supplied and discharged to and from these cylinders independently. In a dump trunk equipped with a switching valve, a solenoid is energized via the limit switch and a solenoid that detects the fully open state of the tellurium gate, and when this solenoid is energized, the cargo box can be tilted. a control valve that disables at least the lifting operation of the cargo box if not energized;
A loading box (rolling device) in a dump trunk characterized by being provided with a