JP3161923B2 - Device for preventing erroneous operation of operation switch in dump truck - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation switch in a dump truck in which a predetermined operation switch is closed while a power switch is closed to drive a load box lifting drive source to raise and lower the load box. Erroneous operation prevention device.

[0002]

2. Description of the Related Art Conventionally, the operation of raising and lowering a cargo box of a dump truck has been performed.
This is performed by the occupant selectively closing an operation switch including an up switch, a neutral switch, and a down switch while the power switch provided on the operation panel is closed.
During traveling when it is not necessary to raise and lower the packing box, or at the time of inspection where it is necessary to fix the packing box at the standing position, unnecessary opening and closing of the packing box can be prevented by opening the power switch. .

[0003]

However, if the occupant forgets to turn off the power switch and the power switch remains closed, the occupant's body touches the operation switch and the packing box moves up and down unexpectedly. There is a possibility that the place where the operation switch is provided is limited.

The present invention has been made in view of the above-mentioned circumstances, and has as its object to reliably prevent unnecessary lifting and lowering of a dump car box due to erroneous operation of an operation switch.

[0005]

According to a first aspect of the present invention, there is provided a driving apparatus for lifting and lowering a load box by closing a predetermined operation switch with a power switch closed. In a dump truck that drives the power source to raise and lower the packing box, it starts by closing the power switch.
A timer is provided to open the power switch when the time is up , and the operation switch is closed while the timer is counting.
When the timer is reset, the timer is reset and a new start is started.
Characterized in that it.

[0006]

[0007]

According to the first aspect of the present invention, when the power switch is closed, the timer starts, and the operation switch can be closed to move the packing box up and down until the timer expires. Even if the occupant forgets to open the power switch after completing the lifting / lowering operation of the packing box, the power switch is opened by the time-out of the timer, so that unexpected lifting and lowering of the packing box is prevented.

In addition, even when the lifting / lowering operation of the packing box is performed for a long time, the timer is reset every time the operation switch is closed, so that it is not necessary to repeatedly close the power switch.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 9 show an embodiment of the present invention. FIG. 1 is a side view of a main part of a dump truck, FIG. 2 is an enlarged view of a spool valve and an actuator, and FIG. 4 is a front view of the operation panel, FIGS. 5 to 7 are block diagrams of a control system, FIG. 8 is a flowchart for explaining the operation, and FIG. 9 is a diagram showing target position data when the spool is moved to the lower position.

As shown in FIG. 1, a cabin 2 is provided at the front of a body frame 1 of a dump truck V, and a packing box 3 is pivotally supported at the rear of the cabin 2 so as to be able to stand up and down. A single-acting hydraulic cylinder 4 is provided between the body frame 1 and the packing box 3, and the packing box 3 is raised by driving the hydraulic cylinder 4 to extend, and the hydraulic cylinder 4 is contracted. As a result, the packing box 3 falls down.

A PTO device 5 is connected to an engine (not shown) arranged at a lower portion of the cabin 2, and an oil pump 6 driven by the PTO device 5 pumps oil from an oil tank 7 through a spool valve 8 to hydraulic pressure. When supplied to the cylinder 4, the hydraulic cylinder 4 extends and the packing box 3 stands. When the packing box 3 falls down, the hydraulic cylinder 4 contracts due to its own weight, and the oil in the hydraulic cylinder 4 returns to the oil tank 7 via the spool valve 8.

The "contact" and "disconnection" of the PTO device 5 are switched by an air cylinder 11 connected to an air tank 9 via a solenoid valve 10. Also, the spool valve 8
The spool valve 8 is controlled by an actuator 12
, The neutral position and the lowered position are switched.
A key switch 13 for operating the start / stop of the engine and an operation panel 1 for operating the lifting / lowering of the packing box 3 are provided inside the cabin 2.
4 are provided. The electronic control unit U controls the operation of the solenoid valve 10 and the actuator 12 based on signals from the key switch 13 and the operation panel 14.

Next, the structure of the spool valve 8 will be described with reference to FIG.

The valve body 15 of the spool valve 8
First oil passage L connected to pressure pump 6₁And the oil tank 7
Second oil passage L_TwoAnd the third oil connected to the hydraulic cylinder 4
Road L _ThreeFrom the spool valve 8 connected to the hydraulic cylinder 4
One-way to allow only oil flow to hydraulic cylinder 4
Fourth oil passage L with valve 16 interposed_FourAre formed. valve
A first oil passage L is provided in a spool hole 17 formed in the body 15.
₁And the fourth oil passage L_Four1st port P communicating with₁And the second
Oil passage L_TwoPort P communicating with_TwoAnd the third oil passage L_ThreeTo
Third port P that communicates_ThreeAre formed. Meanwhile, spoo
The spool 18 slidably fitted in the
Step 18₁Are formed, and this groove 18 is formed.₁Left end of
18 tapered notch_TwoAre formed in plurality.

FIG. 2 shows a state in which the spool 18 is at the neutral position, and when the spool 18 moves rightward from FIG.
The upper position is shown in FIG. 3A, and the lower position shown in FIG.

Next, the structure of the actuator 12 will be described with reference to FIG.

A first gear housing 20 and a second gear housing 21 are connected to the left end of the guide cylinder 19 connected to the left end of the valve body 15. The left end of the spool 18 extends into the inside of the guide cylinder 19, and the female screw member 2
2 are connected by a pin 23. The groove 22 _1, which is engraved in the axial direction on the outer periphery of the female screw member 22, the tip of the bolt 24 which is screwed into the guide cylinder 19 and is engaged, thereby axially state the spool 18 which is regulated the rotation Is allowed to slide.

The first gear housing 20 rotatably supports a male screw member 25 screwed to the female screw member 22 via a ball bearing 26 and a seal member 27. First gear housing 20 and second gear housing 2
A fourth gear 29 is supported via a torque limiter 28 at the left end of the male screw member 25 extending into the inside of the first gear 1.
A first gear 31 of a motor 30 provided on an outer surface of the first gear housing 20 meshes with the fourth gear 29 via a second gear 33 and a third gear 34 provided on an intermediate shaft 32. On the other hand, a potentiometer 35 provided on the outer surface of the second housing 21 is connected to the male screw member 25 via a fifth gear 36 and a sixth gear 37.

The male screw member 25 is driven by the motor 30.
Is rotated, the spool 18 is driven in the axial direction together with the female screw member 22 meshing therewith. The potentiometer 35 detects whether the spool 18 is at the raised position, the neutral position, or the lowered position.

Next, the operation panel 14 will be described with reference to FIGS.
The structure of will be described.

The operation panel 14 is provided with a power switch 38, a power lamp 39, three operation switches 40, 41, 42 and a timer 43. The power switch 38 is an automatic reset type. When the power switch 38 is turned to the right, it closes and the power lamp 39 lights up.
At the same time, the timer 43 is started by the timer start means 44. The count time of the timer 43 is, for example, 1
When the timer 43 times out after one minute has elapsed, the power switch 38 is automatically opened and the power lamp 39 is turned off.

When the power switch 38 is closed, that is, when the power lamp 39 is lit,
0, when the neutral switch 41 or the down switch 42 is closed, the actuator 12 operates to drive the spool 18 of the spool valve 8 to the up position, the neutral position or the down position. When the up switch 40, the neutral switch 41 or the down switch 42 is closed, the timer 43 being counted is reset by the timer reset means 45, and the timer 43 starts counting again. Therefore, if any of the operation switches 40, 41, 42 is closed within one minute,
The power switch 38 is kept closed without being opened.

As shown in FIG. 6, the PTO switching means 46 provided in the electronic control unit U drives the solenoid valve 10 based on the operation of the up switch 40, the neutral switch 41 or the down switch 42, and the PTO device 5 "Contact"·
“OFF” is switched.

As shown in FIG. 7, a target position data converter 47 provided in the electronic control unit U outputs target position data of the spool 18 based on the operation of the up switch 40, the neutral switch 41, or the down switch 42. The positioning control means 48 outputs a motor drive signal based on the target position data to output the motor 30
Drive. At this time, the actual position data of the spool 18 from the potentiometer 35 of the actuator 12 is fed back to the positioning control means 48, and the spool 18
Is converged to the target position.

Next, the operation of the embodiment of the present invention having the above-described configuration will be described with reference to the flowchart of FIG.

First, when the power switch 38 of the operation panel 14 is closed while the key switch 13 is closed and the engine is running, the power is turned on and the power lamp 39 is turned on (steps S1 and S2), and the timer is turned on. 43 starts (step S3). When the raising switch 40 of the operation panel 14 is closed while the power is on, the solenoid valve 10 is operated by a command from the electronic control unit U, the PTO device 5 is brought into "contact", and the hydraulic pump 6 is driven. (Step S5), the actuator 12 is operated by a command from the electronic control unit U, and the spool 12 of the spool valve 8 is driven to the raised position (Step S6). At this time, the timer 43 that is already counting is reset and newly started (step S15).

Then, as is apparent from FIG.
The oil pumped from the oil tank 7 by the hydraulic pump 6 is supplied to the first oil passage L ₁ , the first port P ₁ , and the fourth oil passage L ₄
Then, it is supplied to the hydraulic cylinder 4 via the one-way valve 16, and the packing box 3 stands up when the hydraulic cylinder 4 expands.

When the neutral switch 41 of the operation panel 14 is closed (step S7), the PTO device 5 is left as it is (step S8), and the actuator 12 is operated by a command from the electronic control unit U to operate the spool valve. 8 is driven to the neutral position (step S9). At this time, the timer 43 that is already counting is reset and newly started (step S15).

As a result, as is apparent from FIG.
Oil pumped from oil tank 7 by pump 6
Is the first oil passage L₁, 1st port P₁, Groove 18₁,
Second port P_TwoAnd the second oil passage L_TwoThrough the oil tank 7
While the third oil passage L _ThreeIs blocked by the spool 12.
And the fourth oil passage L_FourIs closed by the one-way valve 16
As a result, the hydraulic cylinder 4 is locked and the packing box 3 is
To stop.

When the lowering switch 43 of the operation panel 14 is closed (step S10), the solenoid valve 10 is operated by a command from the electronic control unit U, the PTO device 5 is turned off, and the hydraulic pump 6 is stopped. At the same time (step S11), the actuator 12 is operated by a command from the electronic control unit U, and the spool 12 of the spool valve 8 is driven to the lowered position (step S12). At this time, the timer 43 that is already counting is reset and newly started (step S15).

As a result, as is clear from FIG. 3B, the oil in the hydraulic cylinder 4 is displaced by the weight of the packing box 3 by the third oil passage L ₃ , the third port P ₃ , the groove 18 ₁ , and the second port P.
After _two and a second oil passage L ₂ is refluxed to the oil tank 7, crates 3 are laid down. At this time, as shown in FIG. 9, the actuator 12 moves the spool 18 of the spool valve 8 to, for example, 2
Since it is slowly moved from the neutral position to the lowered position over a period of seconds, the occurrence of a shock can be prevented and the packing box 3 can smoothly fall down. Further, at this time, the notches 18 ₂ formed in the grooves 18 ₁ of the spool 12 slowly communicate with the third port P ₃ , so that the packing box 3 can be more smoothly laid down.

On the other hand, if none of the operation switches 40, 41, 42 is closed in steps S4, S7, S10, the PTO device 5 and the spool 12 are held as they are (S13, S14), and the timer 43 is eventually turned off. When the time is up (step S16), the power switch 38 is automatically opened (step S17).

That is, when none of the operation switches 40, 41, 42 is closed within one minute which is the count time of the timer 43 after the power switch 38 is closed, or when any of the operation switches 40, 41 Power switch 38 is automatically opened one minute after the last closing of the operation switches 40, 41, 42 even if the occupant's body accidentally touches the operation switches 40, 41, 42 when the vehicle is running. Box 3 stands up
There is no lodging.

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.

For example, the count time of the timer 43 is 1
The time is not limited to minutes, and can be set arbitrarily.

[0037]

According to the present invention as described above, according to the present invention, a timer started by closing of the power switch is provided, since the opening of the power switch by timeout of the data <br/> timer, the crates the lifting work Even if the occupant forgets to open the power switch after the completion of the operation, the power switch is opened due to the expiration of the timer, and the unexpected rise and fall of the packing box is prevented.

[0038] Further, when the operation switch during the count of the timer is closed, because the timer is reset to new start, a long period of time beyond the count time of the timer
Even when carrying out the lifting and lowering work of the packing box over a long period, it is not necessary to repeatedly close the power switch, and the convenience is improved.

[Brief description of the drawings]

FIG. 1 is a side view of a main part of a dump truck.

FIG. 2 is an enlarged view of a spool valve and an actuator.

FIG. 3 is an explanatory diagram of an operation.

FIG. 4 is a front view of the operation panel.

FIG. 5 is a block diagram of a control system.

FIG. 6 is a block diagram of a control system.

FIG. 7 is a block diagram of a control system.

FIG. 8 is a flowchart illustrating an operation.

FIG. 9 is a diagram showing target position data when the spool is moved to a lower position.

[Explanation of symbols]

 3 Packing Box 4 Hydraulic Cylinder (Drive Unit for Lifting / Lowering Packing Box) 38 Power Switch 40 Up Switch (Operation Switch) 41 Neutral Switch (Operation Switch) 42 Down Switch (Operation Switch) 43 Timer

Continuation of front page (56) References JP-A-59-156840 (JP, A) JP-A-58-202121 (JP, A) JP-A-5-221258 (JP, A) JP-A-60-151139 (JP, A) , A) Japanese Utility Model Application Hei 5-68739 (JP, U) Japanese Utility Model Application Hei 5-32114 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60P 1/04

Claims (1)

(57) [Claims] When a predetermined operation switch (40, 41, 42) is closed with the power switch (38) closed, the load box lifting drive source (4) is driven to drive the load box (3). )
Starting and closing the power switch (38) in a dump truck that raises and falls
A timer (43) is provided for opening the power switch (38) by an up, during counting of the timer (43)
When the operation switches (40, 41, 42) are closed,
Timer (43) and wherein the this <br/> to start a new one is reset, error prevention equipment of the operation switch in the dump truck.