JPH0532260B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for preventing accidents caused by a dump truck traveling with its cargo bed in a dumped state, that is, a scalloping accident.

[Conventional technology]

When unloading cargo loaded on the platform of a dump truck backwards, a dumping operation is performed in which the platform is lifted so as to be tilted toward the rear. If you accidentally drive the truck while the truck is in a lifted state, that is, in a dump truck state, the tip of the truck will hit piping, electrical wires, or other structures above the driving range of the dump truck. Accidents may occur.

Conventionally, various devices have been devised to prevent this scallop accident. In the first conventional example shown in FIG.
It uses a buzzer that keeps ringing. In the second conventional example shown in FIG. 4, when the dump lever 3 is pulled to enter the dumping state, the stopper bar 5 is lifted up below the accelerator pedal 4, the accelerator pedal 4 becomes immobile, and the engine of the dump truck is placed in an idling state. It is what it is. In the third conventional example shown in FIG. 5, when the dump state is reached, the pendulum-shaped mark 6, which had been suppressed at the tip of the loading platform 1, comes down to the front of the windshield, allowing the driver to recognize the dump state. It is. This pendulum-shaped mark 6
A round mark called a moon shape 8 is provided at the tip of a rotatably pinned bar 7. Under normal conditions, one end of the bar 7 is held down by the tip of the loading platform 1, and the moon shape 8 is not operated. disappeared from one's sight.
When the vehicle is in the dump state, the bar 7 is rotated by the weight of the moon shape 8, so that the moon shape 8 descends in front of the windshield. In the fourth conventional example shown in FIG. 6, a return spring 9 is attached to the dump lever 3 that puts the loading platform 1 into the dump state, and when the driver releases the dump lever 3, the dump lever 3 is forcibly returned to its original state. This prevents the loading platform from remaining in the dumped state.

[Problem that the invention seeks to solve]

(1) In the first conventional example, if the sound of the buzzer 2 is low, it is ineffective at a noisy construction site, and if the sound of the buzzer 2 is loud, it causes mental pain to the driver, which is harmful to workers. There were problems with the environment.

(2) In the second conventional example, although the accelerator pedal 4 does not work, the engine is in an idling state, so if you shift to a low gear, you can drive freely, and there is still a possibility of a scalloping accident. . Furthermore, when this low gear driving was performed on a rough road, the driver could not feel that the stopper bar was working and could not recognize that the vehicle was in a dump state.

(3) In the third conventional example, the rotatable mark is exposed to wind and rain. Therefore, it lacked durability and was easily broken. In addition, while driving, this landmark caused a rattling noise, which sometimes caused mental distress to the driver.

(4) In the fourth embodiment, when the dump state must be maintained for a long time,
For example, it is necessary to fix it with a pin 10 or the like. However, there is a possibility that you may forget to remove the pin.
The possibility of a scallop accident remained.

[Means for solving problems]

In order to solve the above-mentioned problems, the inventor of the present invention has devised a device that automatically applies brakes to the wheels of a dump truck when the dump truck is in a dumping state. However, simply applying the brakes may not allow the cargo to be completely unloaded from the loading platform unless the dump truck is driven several meters back and forth in the dumped state. For example, coke,
The cargo includes raw materials, large steel slag, etc.
Therefore, we have invented a device that allows the driver to release the brake at his/her discretion and enable the vehicle to drive in a low gear.

That is, a limit switch is provided in the range in which the loading platform moves with the dumping operation, and this limit switch detects the dumping state and applies brakes to the wheels. On the other hand, a release switch for releasing the brake is provided at the grip of the dump lever that puts the cargo platform in the dump state, and the driver can move by pressing the release switch with his/her finger at any time. At this time, the driver cannot change gears because one hand is on the steering wheel and the other hand is on the dump lever, so the vehicle can only drive in a low gear.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. Before that, since the present invention relates to a brake system for a dump truck, an example of a conventional brake system will be explained with reference to FIG. This brake works by air pressure, and the front and rear wheels are braked by separate air tanks (AT1, AT2). No.1 air tank 11
are connected to brake chambers (B, C) 14 via relay valves (L, B) 13, and drum brakes (D, B) 15 are operated by this brake chamber (B, C) 14. The brake shoe 16 widens and the brake is applied. Similarly, the No. 2 air tank 12 is connected to the brake chamber (B, C) 18 via another relay valve (L, B) 17 to operate the rear wheel brake drum (D, B) 19. The relay valves 13 and 17 are opened and closed by an air signal guided through the brake pedal 20. That is, an air signal pipe 21 is led from the No. 1 air tank 11 and connected to two relay valves 13 and 17 via a brake pedal 20. An air gauge 2 is located in the middle of this air signal tube 21.
2 is present to indicate the air pressure. When the brake pedal 20 is stepped on, air pressure is transmitted to the relay valves 13 and 17, and this air signal opens the relay valves 13 and 17.
Pressure air flows into the brake chambers 14, 18 from the air tanks 11, 12 through 3, 17,
The brakes work as described above.

This embodiment is implemented as shown in FIG. 1 for the conventional brake system shown in FIG. 7. First, a double check valve 31 is provided in the middle of the air signal pipe 21. The air signal pipe 21 is connected to one of the double check valves (W, C, B) 31. On the other side, another air signal pipe 32 is led from the No. 1 air tank 11 and connected via magnetic switches (M, S) 33. The double check valve 31 transmits a pressure signal to the relay valves 13, 17 to open the relay valves 13, 17 when pressure is received from at least one of the air signal pipes 21, 32. Further, the magnetic switch 33 opens the air passage only when current flows. A battery 34 is connected to one electrode of the magnetic switch 33, and a limit switch (L, S) 35 is connected to the other electrode. A release button 36 provided at the tip of the dump lever 3 is further connected in series to the limit switch 35. The other electrode of the release button 36 is grounded. The limit switch 35 is provided in a range where the loading platform 1 moves with the dumping operation, and when the loading platform 1 is in the dumping state and the loading platform is separated from the limit switch 35, it is turned off and an electric circuit is opened. When the release button 36 is pressed arbitrarily by the driver's hand, it turns on and closes the electric circuit. Note that a kill switch 37 is provided between the battery 34 and the magnetic switch 33 to cut off the electric circuit.

[Effect of the embodiment]

The operation of the above embodiment will be explained with reference to the flowchart shown in FIG. First, when the driver pulls the dump lever 3 and the loading platform 1 enters the dumping state, the loading platform 1 separates from the limit switches (L, S) 35. This turns on the limit switch. At this time, since the driver has not pressed the release button 36, current flows through the electric circuit and the magnetic switches (M, S) 33 are turned on. This opens the air passage of the magnetic switch 33. When the air passage of the magnetic switch 33 opens, air flows from the No. 1 air tank 11 through the air passage of the magnetic switch 33 and the double check valves (W, C, B) 31, and then to the relay valves (L, B) 13, Reach 17. This opens relay valves 13 and 17. Then
No. 1 air tank 11 and No. 2 air tank 12 flow to brake chambers (B, C) 14, 18 via relay valves 13, 17, respectively. As a result, the brake drums (D, B) work to spread the brake shoe 16 and apply the brakes.

Next, when the vehicle moves forward several meters in the dumped state and unloads the cargo, the release button 36 of the dump lever 3 is pressed. This stops the current in the electric circuit and turns off the magnetic switch 33. Then, the air passage of the magnetic switch 33 is closed. This stops the air from No. 1 air tank 11,
Relay valves 13 and 17 are closed. Therefore, the supply of air to the brake chambers 14, 18 is stopped, and the drum brakes 15, 19 are released.
Therefore, the dump truck is ready to travel. At this time, the driver is holding the steering wheel with one hand and the dump lever with the other hand, so the vehicle is running in a low gear.

Furthermore, when the release button 36 of the dump lever 3 is released, current flows through the electric circuit again and the magnetic switch 33 is turned on. As a result, the drum brakes 15 and 19 operate in the above order.

Now that the cargo can be unloaded from the loading platform, return the dump lever 3 to return to the dump state.

Then, the loading platform 1 comes into contact with the limit switch 35 again, and the limit switch 35 is turned on, thereby releasing the disc brake by the reverse actions described above.

This allows normal driving.

[Other Examples]

In the above invention, the release button 36 is pressed in the axial direction by the driver's hand to turn on the switch, but in other embodiments, the release button 36 is pressed diagonally and pushed down to turn on the switch. It may be one that is turned on and returns to its original state when the pressure is stopped.

〔Effect of the invention〕

According to the scallop accident prevention device for a dump truck of the present invention, the brakes are automatically applied in the dumping state, and the vehicle can then run in a low gear necessary to dump the cargo. Further, the problems such as those of the first to fourth conventional examples can be solved. In other words, (1) there is no buzzer-like noise, (2) there is no limitless driving in low gear, and there is no need for the driver to sense whether or not the accelerator is engaged. In addition, (3) there are no landmarks outside the operator's cab, so the device is highly durable and does not cause noise due to movement of the landmarks. (4) Since there is no need to use pins to maintain the dumped state for a long period of time, there is no possibility of scalloping accidents caused by forgetting to remove the pins.

[Brief explanation of the drawing]

FIG. 1 is an electrical and air circuit diagram showing an embodiment of the present invention, FIG. 2 is a flow diagram showing the operation of FIG. 1, and FIGS. 3 to 6 are diagrams showing conventional technology.
FIG. 7 is an electrical and air circuit diagram showing a conventional brake system. 1... Loading platform, 2... Buzzer, 3... Dump lever, 4
...Accelerator pedal, 5...Stopper bar, 6...Mark, 7...Bar,...Moon shape, 9...Return spring, 1
1, 12... Air tank, 13, 17... Relay valve, 14, 18... Brake chamber, 15, 19
...Drum brake, 16...Brake shoe, 20
...Brake pedal, 21...Air signal tube, 22...Air gauge, 31...Double check valve, 32...
Air signal tube, 33...Magnetic switch, 34
...Battery, 35...Limit switch, 36...Release button, 37...Kill switch.

Claims (1)

[Claims] 1. A limit switch is provided in the range where the loading platform moves with the dumping operation to detect the dumping state and apply the brakes to the wheels, and a limit switch is provided at the grip of the dump lever and is pressed arbitrarily by the driver's hand to apply the brake. A scallop accident prevention device for a dump truck, comprising a release switch.