JPS5912494B2 - Door opening/closing device for dump trucks, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a door opening/closing device for a dump truck or the like, which allows the opening and closing of a rear door of a dump truck or the like to be electrically operated from inside the driver's cabin.

General dump trucks are equipped with a so-called automatic opening/closing device that opens or locks the rear fan door in conjunction with the operation of dumping cargo boxes. It is necessary to dump the door while it is secured, and for this purpose, a manual opening/closing device is often provided in addition to the automatic opening/closing device.

Conventionally, the above-mentioned manual opening/closing device generally has a structure in which a cargo box is equipped with a link mechanism lashing device that is operated by the driver each time after leaving the driver's cab.

However, it is extremely troublesome for the driver to leave the driver's cab each time an operation is to be performed, and there is a demand for a structure that allows all operations to be performed within the driver's cab.

In order to satisfy these demands, the present invention provides a device in which the operating section of a manual opening/closing device is introduced into the operator's cab by an electric cord, thereby making it easy to operate.

The embodiment will be described below with reference to the drawings. 1 is a driver's cab of a dump truck, 2 is a cargo box mounted on a subframe 3 of an automobile body, and the rear part is pivoted to the subframe 3 by a hinge pin 4.

Reference numeral 5 denotes a swing door which can be rotated by being pivoted at the upper part of the rear end of the cargo box 2, and has a horizontal shaft 7 at its lower end that engages with a lashing pawl 6 which is pivoted at the rear end of the bottom of the cargo box 2. It is a setup.

The lashing claw 6 is attached to the base end of the lashing claw 6 by moving it up and down.
When engaged, one end of the transmission link 8 is connected by a put point method to prevent the engagement from being released due to vibration etc., and the other end of the transmission link 8 is connected to the piston rod of the air chamber device 9, which will be described later. It is connected to 10.

The air chamber device 9 has a casing 11 fixed to the bottom of the cargo box 2, and a front chamber 1 inside the casing 11 with a diaphragm 12.
3 and a rear chamber 14, and the rear chamber 14 is provided with a piston rod 10 whose base end is fixed to the diaphragm 12 and whose other end protrudes from the casing 11, and a spring 15 that pushes the diaphragm 12 toward the front chamber 13 side. The front chamber 13 has a structure in which the front chamber 13 communicates with an air tank 16 mounted on the vehicle body through an air pipe 17.

Reference numeral 18 denotes a solenoid valve interposed on the air pipe 17, which opens and closes the passage of the air pipe 170 by turning on and off the current.

A first cord 20 from a DC power source 19 is connected to the solenoid valve 18, and a relay switch 23 connected to the first cord 20 is connected and disconnected by a limit switch 21 and a relay 22 from the DC power source 19 side. are successively interposed.

The limit switch 21 is fixed to the subframe 3 so that it is in the "off" state when the cargo box 2 is in the lowest position and is in the "connected" state in the dumping state.

24.25 is limit switch 21 and relay switch 2
The second code 24 is connected to the relay 22 and is interposed with a main switch 26 provided in the driver's cab 1, and the third code 25 is connected to the relay 22 in parallel with the second cord 24, and has a dump angle detection switch 27 interposed therein.

The third cord 25 is provided with a relay switch 28 for keeping the link 22 energized in parallel with the dump angle detection switch 2T.

The dumping angle detection switch 27 is located close to the cam 29 attached to the hinge pin 4, and when the cargo box 2 is dumped with earth and sand etc. on it and the sliding door 5 is secured, two fixed angles α If the angle exceeds a certain angle α, the vehicle body may roll backwards or the hinge part may be damaged.
As shown in the figure, the dump angle detection switch 27 is turned on, the fan door 5 is opened, earth and sand are discharged, and when the angle becomes less than a certain angle α, the dump angle detection switch 27 is turned off as shown in Figure 3. It's supposed to be.

30 is a pressure switch interposed on the air pipe 17 between the air chamber device 9 and the solenoid valve 18, which is "on" when there is air pressure in the air pipe 17, and "off" when there is no air pressure. It is further connected to a lamp 31 provided in the driver's cab 1 by a cord 32.

The present invention has the above configuration, and its operation will be explained next.

When the cargo box 2 is in the lowest storage position, the limit switch 21 is always turned off, cutting off the power to the solenoid valve 18.

Therefore, air is not supplied to the front chamber 13 of the air chamber device 9, and by pushing the piston rod 10 toward the front chamber 13 side by the force of the spring 15, the transmission link 8
The horizontal shaft 7 is engaged with the securing die 6 through the .

Now, to dump the cargo box 2 and discharge earth and sand, etc., the main switch 26 is first turned on, and when the cargo box 2 is dumped, the limit switch 21 is turned on, and the relay 22 is energized.

As a result, the relay switch 23 of the first code 20 also
The solenoid valve 18 is turned on, and the air pipe 17 is opened.

The air in the air tank 16 is supplied to the front chamber 13 of the air chamber device 9, and the supplied air overcomes the force of the spring 5 and pushes the diaphragm 12 toward the rear chamber 14.
The solenoid rotates the securing mold 6 up and down via the piston rod 10 and the transmission link 8 to release the engagement with the rear shaft 7.

This allows the earth and sand in the cargo box 2 to be discharged.

Next, when the cargo box 2 is lowered, the limit switch 21 is turned off at the lowest position, cutting off the power to the solenoid valve 18, thereby causing the air pipe 1
7 becomes "closed".

Therefore, the air in the front chamber 13 of the air chamber device 9 is released into the atmosphere, and the piston rod 10 is pushed toward the front chamber 13 by the force of the spring 5.
After that, the main switch 26 is turned off.

If you forget to set the main switch 26 to "connect" and dump the cargo box 2, the limit switch 21 will first be set to "
When the dump angle reaches a certain angle α or more after further dumping, the dump angle detection switch 2 of the third code 25 is activated.
7 becomes "connected" and energizes the relay 22.

As a result, the relay switch 28 of the third cord 25 and the relay switch 23 of the first cord 20 become "connected",
The solenoid valve 18 is energized, the air pipe 17 is opened, the air in the air tank 16 is supplied to the air chamber device 9, and the engagement of the horizontal shaft 7 by the securing die 6 is released.

Next, when the cargo box 2 is lowered, the dump angle detection switch 27 is turned off when the dump angle becomes less than a certain angle α.
However, the relay switch 28 of the third cord 25 keeps the relay 22 energized, and the solenoid valve 1
8 is also maintained, keeping the air tube 17 "open".

When it is further lowered and reaches the lowest position, the limit switch 21 is turned off, the energization to the solenoid pulp 18 is cut off, and the air pipe 17 is turned off.

As a result, the horizontal shaft 7 is engaged with the lashing claw 6.

When draining soil, sand, etc., press the main switch 26.
If you dump the water to the angle required for draining (around 10 degrees) with it set to "off", the horizontal axis 7 will be lower than the fixed angle α.
are kept engaged with the lashing claws 6, and water can be drained without discharging earth and sand.

The pressure switch 30 is turned on when air is supplied to the air pipe 17, and turned off when no air is supplied to the air pipe 17, and turns on or off the lamp 31 in the driver's cab 1. It is designed to turn off the light to notify the operating status.

As described above, in the present invention, all operations for opening and closing the fan door can be performed from within the driver's cab, so there is no need to come out of the driver's cab each time an operation is to be performed.

Furthermore, even if you forget to operate the main switch and dump the dump, when the dump angle reaches a certain angle or more, the lashing claw will automatically disengage the fan door, making it possible to reliably discharge dirt, etc. There is no risk of rolling backwards or damaging the hinge.

[Brief explanation of the drawing]

FIG. 1 is an overall view of a dump truck equipped with the present invention, FIG. 2 is a circuit diagram of the present invention, and FIGS. 3 and 4 are enlarged views of a dump angle detection switch. 1 is the driver's cab, 2 is the cargo box, 5 is the fan door, 6 is the lashing claw, 8 is the transmission link, 9 is the air chamber device, 16 is the air tank, and 17 is the air! , 18 is a solenoid pulp, 19 is a DC power supply, 20 is a first cord, 21 is a limit switch, 25 is a main switch, and 27 is a dump angle detection switch.

Claims (1)

[Claims] 1. The lashing claws for lashing the fan door and the air chamber device are connected by a transmission link, the air chamber device and the air tank are connected by an air pipe, and a solenoid pulp is interposed in the middle of the air pipe. In this device which opens and closes the fan door by switching the solenoid pulp, a limit switch and a relay switch which are connected to the first cord connected to the solenoid pulp when the cargo box is tilted are interposed, and the first cord is connected to the solenoid pulp. A main switch is provided which branches a second cord and a third cord in parallel after the cord limit switch, leads the second cord into the driver's cab, and connects/disconnects a relay switch to the second cord located inside the driver's cab. and the third cord is provided with a dumping angle detection switch that contacts the relay switch when the cargo box is dumped at a predetermined angle or more.