JPS60191842A - 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 exampe, rolling down rearward upon unloading work for loaded cargo materials, by providing a limit switch for detecting the fully opened condition of a tail gate in the rear section of the cargo box of the dump truck, and as well providing an operation limiting mechanism which enable the cargo box to be lifted up by means of the solenoid which is energized by the limit switch. 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 as a drive source for an operation limiting mechanism 20 which is so arranged to restrain the operating lever 8a of a manually operated selector valve 8 for the main cylinder 2 while the restraint of the operating lever 8a is released by the operation of the rotary solenoid 16 upon full opening of the tail gate.

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 truck in which a tail cage 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 opens upward at the rear, an auxiliary cylinder 4 that opens and closes the tailgate 3, and the like. 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 hydraulic circuit of conventional cargo box extension devices, one cylinder expands and contracts regardless of the state of the other cylinder. I am now able to do it. However, in order to ensure work safety, when unloading through the air, the driver operates one manual switching valve to extend the auxiliary cylinder 4, and after opening the tailgate 3 as shown by the broken line, 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 this kind of 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 and the cargo box will collapse. The loaded items will remain inside. At this time, as the inclination angle of the cargo box increases, the center of gravity of the loaded object moves backward, so +i'f in
! If the weight is large, the balance of the vehicle may be lost, causing the front wheels to lift off the ground, or in extreme cases, causing the vehicle to roll backwards, which can be extremely dangerous. Additionally, the driver can determine whether the tailgate is open by visually checking that the tailgate 1 is open through the window behind the seat, or by looking at the position of the manual selector valve operating lever. can. However, unloading work in a dump trunk is usually carried out by one person, so there are cases where the position of the operating lever is overlooked or the tail is hidden behind the load and cannot be seen.
Additionally, once you start moving the 411 box, it becomes impossible to observe from the rear window, and you may not notice that the tailgate is closed. Therefore, in order to avoid situations such as the above-mentioned rollover, it is desirable to always open the tailgate when tilting the cargo box. There is a demand for the advent of 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 cargo box from being lifted while the tailgate is not fully opened during the unloading operation of the dump truck. It is an object of the present invention to provide a cargo box tilting device for a dump truck that can prevent the occurrence of accidents such as backward rollover of the truck.

[Structure of the invention]

The features of the present invention will be explained below based on the drawings. The main cylinder 2 (1
31 moves (';J 7r white rear part, auxiliary cylinder 4
This dump truck is equipped with a tailgate 3 that opens in two, and is equipped with manual switching valves 8 and 9 for independently supplying and discharging hydraulic oil to these cylinders 2 and 4. -1 and 3 are fully open.
A solenoid 1G is energized via a solenoid 1G which, when energized, enables the switching operation of the manual switching valve 8 for the main cylinder 2, while if not energized at least its manual switching valve 1.8. The present invention is to provide a cargo box tilting device that can be mounted on a dump truck and is provided with an operation regulating mechanism 20 that disables the lifting operation of the cargo box.

〔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 dump trunk cargo box 1 to which the cargo box tilting device of the present invention is applied. (See Figure 1). This ('+:
On the rear surface of Box J, tailgates 1 and 3 are installed which open upward by means of auxiliary cylinders 4 on each side housed in Box 11 and 1a of Box 1i, as shown in Fig. 3. The operation levers 3a and 9a of the switching valves 8 and 9 independently supply and discharge hydraulic oil to these cylinders 2 and 4.
is installed in the driver's seat (not shown). In addition, □, the second
The opening/closing center 10 of the tails 1 and 3 in the figure is the loading box 1.
If it is a top-opening type near two sides and this type,
There is no problem even if the illustrated arm 11 does not exist. For example, a protrusion 13 is provided on the rotating base 12 of the tailgate 30, so that when the tailgate 3 rotates and becomes fully open as shown by the two-dot chain line, and when it is fully closed as shown by the solid line. Mitotic switches 14 and 15 are installed in the cargo box 1, respectively, to be activated when the vehicle is in use.

In the electric circuit of one sumitoswitch 14,
The rotary solenoid 16 is energized and excited thereby.
is provided as shown in FIG. 4, and a lamp 17 that lights up at the same time as the solenoid 16 is energized and a buzzer 18 that sounds are also provided. In the circuit of the other limit switch 15, the protrusion 13 is connected to P31 from the limit switch 15.
[A lamp 19 is provided that lights up when the camera is turned on. This lamp I9 is installed at a driver's seat (not shown) together with the above-mentioned lamp 17 and buzzer 18, and can inform the driver who operates the cargo box tilting device of the status of the tailgate 3. By the way, the manual switching valve 8 of the main cylinder 2, which is interposed in the hydraulic circuit of the cargo box tilting device that drives the main cylinder 2 and the auxiliary cylinder 4, can be switched when the aforementioned rotary solenoid 16 is energized. On the other hand, there is provided an operation restriction mechanism 20 that at least disables the lifting operation of the cargo box if it is not energized. Incidentally, the operating lever 8a of the manual switching valve 8 is attached, for example, as shown in FIG. Accordingly, the spool of the manual switching valve 8 is moved to switch its position. In this example, the aforementioned operation locking mechanism 20 is as follows:
It is provided on the operation lever 8a and is not shown in FIG. 5(b).
It consists of a rod 22 that is moved forward and backward by the tally solenoid 16, and a regulating plate 23 that projects from the support portion 8b. When the rod 22 advances, this regulating plate 23 is
As shown in , the operating lever 8a is allowed to rotate from the neutral position in the direction of lowering the cargo box as indicated by the arrow, but is prevented from rotating in the direction of raising the cargo box as indicated by the arrow U. In addition, the second
In the figure, a securing mechanism 24 for securing the lower part of the tailgate 3 to the cargo box 1 is attached.

This is provided to prevent the tailgate 3 from opening due to loaded items, and is made up 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 the pin 25 of the car. It consists of a detachable part 27, link parts 28 and 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 will be described later, when the auxiliary cylinder 4 starts to extend, the hook 2G and the pin 25 are released from each other before the tailgate 3 opens, and the binding of the tails 1 and 3 is reduced by 1η''. The tailgate 3 is opened by the auxiliary cylinder 4, which further extends.Conversely, when the auxiliary cylinder 4 contracts and the doors 1 and 3 are closed, the auxiliary cylinder 4 then expands further. Further reduced and detachable part 2
The engagement at 7 is made, and the tails 1 and 3 are secured. In conjunction with the operation of the lashing mechanism 24, in this example, the auxiliary cylinder 4 is
A limit switch 31 is installed that comes into contact with the bracket 30 that rotates due to expansion and contraction of the tailgate 3.
It is now possible to detect ¥ exclusion. In the circuit of this limit switch 31, a lamp 32 (see FIG. 4) that lights up when the blow-soto 30 leaves the limit switch 31 is installed in the driver's seat, similar to the lamps 17 and 19 described above. ing.

According to the configuration described above, the cargo box 1 can be tilted in the following manner, and the cargo box tilting movement can be 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. Furthermore, the tail game
In the soil portions 1 and 3, the lashing mechanism 24 prevents the tailgates 1 and 3 from opening, thereby preventing the cargo from spilling. In this state, the limit switch 14 is
Since it is not in contact with the rotary solenoid, it is not in a energized state, and the lamp 17 remains off, the buzzer 18 does not sound, and the rotary solenoid 16 is not energized. As a result, the rod 22 of the operation regulating mechanism 20 maintains the advanced state shown by the imaginary line in FIG. 5(b), and the regulating plate 23 is prevented from rotating in the direction of the arrow 33 shown in FIG. It has become impossible. In addition, the limit switches 15 and 31 are in contact with the protrusion 13 and the Brage sole 1-30 and are not energized, so that the lamps 19 and 32 remain turned off.

A case in which the vehicle stops and unloads cargo in such a state will be described. Now, even though the driver has not fully opened the tailgate 3, that is, even though the lamps 17, 19, and 32 are off and the cargo box 1 should not be tilted,
Suppose that in this state, the operating lever 8a of the manual switching valve 8, which commands the operation of the main cylinder 2, is operated in the box-lifting direction U by mistake.

However, since the regulating plate 23 comes into contact with the rod 22, rotation of the operating lever 8a in the direction of arrow U is prevented, and the lifting operation of the cargo box 1 is prevented. Therefore, tail game 1.
3 is not fully open, the cargo box will not tilt.

In this way, if the tailgates 1-3 are not fully opened, the cargo box ■ will not tilt. Therefore, when unloading the cargo, the driver must first move the manual switching valve 9 from neutral to position G in order to open the tailgates 1 and 3. Switch to

Hydraulic oil supplied by the hydraulic pump 35 is supplied from the oil passage 34 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-dotted chain line in FIG. However, since the lower portions of the tailgates 1 and 3 are fixed by the lashing mechanism 24, even if the cylinder rod 4b, which is attached to the rotating base 12 of the tailgate 3, extends, the rotating base 12 will not rotate. There's nothing to do.

Therefore, due to the reaction force, the cylinder body 4 (, moves to the left as shown by the two-dot chain line. In other words, the auxiliary cylinder 4
Since it is supported by one end of the bracket 30 which is supported by the loading box 1, it rotates in the direction of arrow 45 around the support point 43 of the bracket 30 or the support point 44 of the bracket 30. At this time, since the arm 46 of the link section 29 that rotates integrally with the bracket 1-30 also rotates in the same direction, the hell crank 47 attached to this arm pushes down the rod 48 in the direction of the arrow 50. This movement is transmitted to the engaging and disengaging portion 27 via the link portion 28.
The pin 25 is rotated in the direction of the arrow 52 around the support point 51, and the pin 25 is removed, removing the tailgate.
Bonds 1 and 3 are lifted. In this way, the hard cotton i mechanism 24
The bracket 30, which has been rotated to activate the engine, moves away from the limit switch 31, so the circuit of the lamp 32 becomes energized (the lamp 32 in the driver's seat lights up. This lighting allows the driver to switch off the tailgate). It can be confirmed that lashings 1 and 3 have been released.Therefore, if this lamp 32 does not light up even though the manual switching valve 9 is operated, the lashing of tailgates 1 to 3 may be confirmed for some reason. Since it is known that the condition is maintained, it is possible to check the lever operation of the manual switching valve 9 or the condition of the cargo box 1. When the tailgate 1-3 is released from the lashing in this way, the extension is stopped. Rotation of the bracket 30 by the continuing auxiliary cylinder 4 is prevented by a 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 base 12 of the tailgate 3 is rotated in the direction of arrow 54 due to the extension of the cylinder rod 4b. Since the protrusion 13 of the rotary base 12 that has started to rotate in this manner moves away from the limit switch 15, the circuit of the lamp 19 becomes energized, and the lamp 19 in the driver's seat lights up.

This lighting allows the driver to recognize that tailgates 1 and 3 have begun to open.
9 and the above-mentioned lamp 32 are not absolutely necessary, but if the lamp that should be lit is off,
It is convenient for the driver to be able to know if there is any abnormality or operational error.

When the auxiliary cylinder 4 is extended and the tailgates 1 and 3 are fully opened, the protrusion 13 of the rotating base 12 engages the limit switch 14. And that time! The rotary solenoid 16 is energized and the lamp 17 is turned on, and the buzzer 18 is activated. In this way, by lighting all the lamps and sounding the buzzer, the driver releases the operating lever 9a of the manual switching valve 9 to stop the extension of the auxiliary cylinder 4, and also indicates that the cargo box 1 may be tilted. You can check it. Since the manual switching valve 9 returns to the neutral position from position G, +Jl of the air supplied to the cylinder chamber 4a of the auxiliary cylinder 4 is prevented from flowing out, and the tailgate 3 is maintained in the fully open state. At this time, the rod 22 of the operation regulation mechanism 20 is retracted as shown by the solid line in FIG. 5(b) due to the excitation of the rotary solenoid 16, so that the regulation plate 2
Rotation in the direction of arrow 33 is possible. When the driver turns the operating lever 8a in the direction of the arrow U to switch the manual switching valve 8 from neutral to position 3, hydraulic oil is supplied to the cylinder chamber 2a of the main cylinder 2 through the oil passage 36. , the cargo box 1 is raised by the extension of the cylinder II cylinder 2b. At that time, the hydraulic oil in the piston chamber 2c is
The oil is drained to the oil tank 41 via the oil tank 41. Do it like this”
Moved ζ times 4! The load 111 is allowed to fall by the J box 1 without being obstructed by the tailgate 3,
ii; r lii, shi can proceed smoothly. therefore,
Since the loaded items do not stay in the cargo box 1 due to the tailgate 3, dangerous situations such as the vehicle body rolling backwards due to the shift of the center of gravity of the loaded items are avoided. Note that when lowering the cargo box 1, the operating lever 8a of the manual switching valve 8 is switched to position F by rotating in the direction of the arrow.

The working oil pressure in the main cylinder 2 becomes atmospheric pressure and is drained into the oil tank 41 via the oil passage 36, and the cargo box 1 is lowered to its original position by its own weight. By the way, you will be asked to unload the cargo box 1 regardless of whether the tailgates 1 and 3 are open or closed.

By the way, when the manual switching valve 9 is set to the bonsion 1 and the auxiliary cylinder 4 is contracted and the tailgate 3 begins to close, the solenoid 16 is demagnetized and the lamp 1 is turned off as described above.
7 goes out and the buzzer 18 also stops sounding. Tail 1
When the door 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 tailgates 1 to 3 are completely closed, the bracket 30 returns to the original position shown in FIG. 2 due to the contraction of the auxiliary cylinder 4 and comes into contact with the limit switch 31, and the lamp 32 is also turned off. At that time, the hellcrank 47 via the arm 46
also rotates, so the rod 48 is pulled up and the engaging/disengaging portion 2
The hook 26 of No. 7 engages with the bin 25, and the tailgate 3 is secured.

In the above explanation of the operation, the above-mentioned operation regulating mechanism 20
is provided on the operating lever 8a of the manual switching valve 8,
The movement of the arm 8c shown in FIG. 5(a) is controlled by the manual switching valve 8.
It may be provided in the middle of the cable 21 that transmits data to a spool (not shown). Although not shown, a regulating arm is provided that swings while maintaining the push/pull action of the cable, and its rotation is regulated by a rod that moves back and forth with the excitation of a rotary solenoid, thereby achieving the same function as described above. You can also leave it as yo・). Further, the solenoid is not limited to the rotary type, but a linear motion type as shown in 4) may be used.

〔Effect of the invention〕

As can be seen from the detailed description of the embodiments below, the present invention is provided with a limit switch that detects that the tailgate 1 is fully open, and a solenoid energized by the limit switch is used to perform at least the lifting operation of the cargo box. Since this makes it impossible to tilt the cargo box, it becomes necessary to open the tailgate 1.

As a result, it is possible to avoid the situation where the cargo box starts to tilt when the tailgate is not fully opened, and the balance of the vehicle body is lost, causing the front wheels to lift off the ground or the vehicle body to roll backwards, as described in the section on conventional technology. You can take steps to prevent extremely dangerous situations like this from occurring.

[Brief explanation of the drawing]

Fig. 1 is an overall schematic diagram of a dump trunk, 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 hydraulic circuit diagram for operating the 4iJ box tilting device. , Figure 4 is a current circuit diagram for each limit switch, Figure 5 (a
), (b) is a front view and a paralytic side view of the operation control lever (several control levers are installed). 1-Loading box, 2-Main cylinder, 3-Tail cage, 4-Auxiliary cylinder, 8.9 - Manual switching valve, 14 - Limit switch, 16 - Solenoid, 20 - Operation regulation mechanism Patent applicant Kyokuto Kaihatsu Kogyo Co., Ltd. Agent Patent attorney Katsutoshi Yoshimura (one idiot) Figure 3 Figure 5 (b)

Claims (1)

[Claims] (1) A tailgate that opens upwards using an auxiliary cylinder is installed at the rear of the cargo box that tilts around the rear of the vehicle using a main cylinder, and hydraulic oil is supplied and discharged to and from these cylinders independently. In a dump trunk equipped with a switching valve, there is a limit switch that detects the fully open state of the tailgate, a solenoid that is energized via this limit switch, and a manual switch of the main cylinder reservoir when this solenoid is energized. An operation regulating mechanism that enables the switching operation of the switching valve, but disables at least the lifting operation of the cargo box of the manual switching valve if it is not energized. Device.