WO2017099268A1

WO2017099268A1 - Method for controlling forklift

Info

Publication number: WO2017099268A1
Application number: PCT/KR2015/013391
Authority: WO
Inventors: 최선호
Original assignee: 주식회사 두산
Priority date: 2015-12-08
Filing date: 2015-12-08
Publication date: 2017-06-15

Abstract

A method for controlling a forklift, according to the present invention, can ensure stability by restricting traveling speed when forks are high, and can improve work efficiency by enabling the inclination of a mast frame to be adjusted according to the will of an operator, even if the inclination of the mast frame is automatically aligned.

Description

Forklift Control Method

The present invention relates to a control method of a forklift, and more particularly, to a control method of a forklift to limit the traveling speed when the mast height is high.

In general, forklift trucks are used to lift or transport workpieces. More specifically, the forklift is driven by lifting the workpiece with the workpiece on the fork and lowering the workpiece when the destination is reached.

At this time, the higher the height of the fork, the driving may become unstable. That is, if the running speed is high in the state where the height of the workpiece is located, there is a problem that the risk of overturning increases.

Therefore, when the forklift travels, it is required to limit the traveling speed of the forklift according to the height of the fork.

On the other hand, the inclination of the fork also inclines with the mast according to the degree of inclination of the mast toward the front of the forklift. Since the workpiece is placed on the fork, the workpiece may fall due to the inclination of the fork tilted forward.

In particular, in the related art, the operator of the forklift truck determines whether the work object falls based on visual information visible to the naked eye, and there is a concern that the work object falls if the worker misunderstands or misjudges it.

However, the actual operation of the forklift may require the inclination of the fork to be increased. However, if the inclination of the fork, that is, the restoring of the tilting of the mast, is set automatically, the inclination of the fork cannot be manipulated as desired by the operator. There is a ham.

(Patent Document 1) Korean Patent Publication No. 10-2014-0048674 (published on April 24, 2014)

The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a forklift control method for preventing a safety accident by limiting the traveling speed when the mast height is high.

Another object of the present invention is to control the forklift to control the inclination angle when the mast is tilted forward to prevent cargo from falling and to further adjust the inclination of the mast according to the will of the operator. To provide.

In order to achieve the above object, the control method of the forklift according to an embodiment of the present invention, the first step (S10) that the lifting of the fork is controlled; A second step (S12) in which the height of the fork is determined; A third step (S16) of determining whether the required traveling speed is faster than a target traveling speed when the height of the fork is equal to or higher than the set height; And a fourth step (s18) of controlling the driving speed of the forklift to decelerate to the target traveling speed when the required traveling speed is faster than the target traveling speed.

In addition, the control method of the forklift according to an embodiment of the present invention, if the height of the fork is lower than the set height 3-1 step (S14) is controlled so that the forklift is driven at the required travel speed; .

In addition, the control method of the forklift according to the embodiment of the present invention, when the height of the fork is equal to or higher than the set height may be to decelerate with the deceleration slope from the current traveling speed to the target traveling speed.

In addition, the control method of the forklift according to the embodiment of the present invention, the deceleration slope may have a gentle slope initially, a sharp slope later.

In addition, the control method of the forklift according to an embodiment of the present invention, the fifth step (S20) is required for the tilting operation of the mast; A sixth step (S22) of determining whether a slope of the mast frame reaches a set slope; A seventh step (S24) of stopping the tilting operation of the mast when the inclination of the mast frame reaches a set slope; An eighth step (S26) in which a tilting operation of the mast is additionally required after the tilting operation of the mast is stopped; A ninth step S28 in which it is determined whether the automatic tilting switch is deactivated; And a tenth step (S30) in which a tilting operation of the required mast is additionally performed if the operation of the automatic tilting switch is released.

In addition, the control method of the forklift according to the embodiment of the present invention, the set inclination may be an inclination inclined 2 degrees in front of the forklift relative to the horizontal line.

In the method of controlling the forklift according to the embodiment of the present invention, when the height of the fork is high, the driving speed of the forklift can be forcibly reduced, thereby preventing a rollover accident. In addition, lowering the height of the fork can control the forklift at the required traveling speed, thereby improving workability.

In addition, the control method of the forklift according to the embodiment of the present invention, after activating the automatic function to stop the inclination of the mast frame to the set inclination, after adjusting the inclination of the mast frame according to the operator's will workability This is further improved.

1 is an explanatory view of a forklift according to an embodiment of the present invention.

2 is a flowchart illustrating an example of controlling the traveling speed of the forklift according to the height of the fork in the control method of the forklift according to the embodiment of the present invention.

3 is a flowchart illustrating an example of controlling an inclination of a mast frame in a forklift control method according to an exemplary embodiment of the present invention.

Hereinafter, a method for controlling a forklift truck according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings so that a person skilled in the art may easily implement the present invention. The present invention is not limited to the embodiments described herein, and may be implemented in various different forms. In order to clearly describe the present invention, parts irrelevant to the description are omitted, and like reference numerals designate like elements throughout the specification.

First, the structure of a forklift is demonstrated with reference to FIG. 1 is an explanatory view of a forklift according to an exemplary embodiment of the present invention.

The forklift is provided with a lift frame 12 inside the mast frame 10. In addition, a lift actuator 20 is installed in the mast frame 10, and the lift frame 12 is lifted and lifted by the operation of the lift actuator 20. The lift frame 12 is provided with a wheel 22. In addition, the front of the mast frame 10 is provided with a fork 40.

In addition, one side of the chain 30 is fixed to the mast frame 10 via the wheel 22, and the other side of the chain 30 is fixed to the fork 40. That is, the fork 40 is raised when the lift actuator 20 is expanded, and the fork 40 is lowered when the lift actuator 20 is reduced.

On the other hand, the lower side of the mast frame 10 is installed in the forklift to enable the rotational movement. Also. The mast frame 10 is provided with a tilt actuator 50 at the rear. The tilt actuator 50 is installed in the main body of the forklift. That is, when the tilt actuator 50 is extended, the mast frame 10 is inclined forward. And when the tilt actuator 50 is reduced in operation, the mast frame 10 is tilted toward the rear.

The tilt actuator 50 may be operated by hydraulic pressure. In more detail, the hydraulic pump 61 for discharging the hydraulic oil in which the hydraulic pressure is formed, the valve unit 62 which opens and closes according to the tilting pilot signal to provide the hydraulic oil to the tilt actuator 50, and the tilting pilot signal as the operator operates. The operation part 63 which generate | occur | produces is included.

On the other hand, if the operation unit 63 is not operated, the valve unit 62 is maintained in a neutral state, whereby the operation of the tilt actuator 50 is stopped, and the posture of the mast frame 10 is maintained.

In addition, the forklift is provided with an inclination detection sensor 74 for detecting the inclination of the mast frame 10. The inclination detection sensor 74 can detect the inclination of the mast frame 10, and since the fork 40 is installed in the mast frame 10, the inclination of the fork 40 can be known. In particular, the inclination of the fork 40 may be obtained based on the forklift, and the absolute inclination may be obtained based on the horizontal line. The tilt detection sensor 74 uses a known technique, and further description thereof will be omitted.

In addition, the mast frame 10 is provided with a height detection sensor 72 to detect the height of the fork 40. That is, the height of the fork 40 is detected by the height detection sensor 72 to determine whether the height of the fork 40 is higher or lower than the set height. The height detection sensor 72 uses known techniques, and further description thereof will be omitted.

Hereinafter, a traveling speed of a forklift in a method of controlling a forklift according to an embodiment of the present invention will be described with reference to FIG. 2. 2 is a flowchart illustrating an example of controlling the traveling speed of the forklift according to the height of the fork in the control method of the forklift according to the embodiment of the present invention.

When driving the forklift, the fork may be raised first before running, but the fork may continue to be raised even after driving starts. Of course, if you are an experienced and experienced worker, you will drive safely by keeping the fork height appropriate. However, even inexperienced or skilled workers may be overspeed even if the height of the fork is high due to a mistake or misjudgment. The present invention is to limit the speed when the fork height is high.

Each step will be described below.

First step (S10): The fork lift is controlled. That is, the worker raises the fork 40 while loading the cargo on the fork 40 so that the fork 40 is positioned at an appropriate height. In this case, the fork 40 is lifted by the lift actuator 20 being extended to lift the lift frame 12, whereby the chain 30 is pulled up by pulling the fork 40.

Second step (S12): The height of the fork is determined. The lift height of the fork 40 or lift frame 12 is closely related to the overturning of the forklift. That is, the higher the height of the fork 40 or the lift frame 12, the greater the risk of a rollover accident. Therefore, it is necessary to check whether the height of the fork 40 or the lift frame 12 is lower than the set height.

The above-described set height can be known by the height detection sensor 72. That is, if the height detecting sensor 72 is detected while the fork 40 or the lift frame 12 is raised, it may be determined that the set height has been reached. On the other hand, even if the detection signal is detected in the height detection sensor 72, if the fork 40 or the lift frame 12 continues the synergism, it is determined that the height of the fork 40 or the lift frame 12 is excessively high. Can be. On the other hand, if no signal is detected by the height detection sensor 72 while the fork 40 or the lift frame 12 is raised, it may be determined that the fork 40 or the lift frame 12 is still at a low position. have.

Third Step (S16): When the height of the fork is equal to or higher than the set height, it is determined whether the required traveling speed is faster than the target traveling speed. When the height of the fork 40 or the lift frame 12 is equal to or higher than the set height, it is determined whether the required traveling speed is faster than the target traveling speed. The required traveling speed may be a signal when the operator manipulates the driving lever or the driving pedal to drive the forklift. In detail, even if the operator operates the driving lever or the driving pedal for driving, the driving speed of the forklift is immediately reflected and the running speed of the forklift does not change in real time, but has a slight time difference. Therefore, if the required driving speed is large, it can be predicted that there is a risk of overspeed, but it can be understood that the forklift is not actually overspeed.

Fourth Step (S18): When the height of the fork 40 or the lift frame 12 is equal to or higher than the set height, if the required traveling speed is faster than the target traveling speed, the driving speed of the forklift is controlled to be decelerated to the target traveling speed. Step.

If the required traveling speed is faster than the target traveling speed, the risk of a rollover accident is likely to increase, and the driving speed is decelerated controlled so as to decelerate to a speed significantly lower than the required traveling speed.

In addition, even when the height of the fork 40 or the lift frame 12 is equal to or higher than the set height, and the required traveling speed is faster than the target traveling speed, the maximum speed of the traveling speed may be limited.

That is, the present invention can substantially prevent the speed of the forklift by controlling the forklift to decelerate before actually speeding faster than the target travel speed.

Therefore, the control method of the forklift according to the embodiment of the present invention can operate the forklift by reflecting the required traveling speed generated by the request of the operator only when the fork 40 or the lift frame is lower than the set height.

And the control method of the forklift according to the embodiment of the present invention can prevent the forklift from speeding up by controlling the required driving speed to be decelerated when the height of the fork 40 or the lift frame 12 is equal to or higher than the set height. This makes it possible to drive the forklift more safely.

On the other hand, the present invention may further include a step 3-1 (S14). Step 3-1 (s14) is a case where lifting and lowering control of the fork is performed at the will of the operator while traveling. That is, if the height of the fork 40 or the lift frame 12 is lower than the set height, the traveling speed can be normally implemented so that the required traveling speed is realized so that the forklift can be driven in a more stable state. do.

In addition, even if the height of the fork 40 or the lift frame 12 is high, if the running speed is slow, it may be determined that the safety from the risk of the rollover, the running speed is normally controlled to reflect the required running speed (S14).

On the other hand, if the height of the fork is equal to or higher than the set height, the fork may be decelerated with the deceleration slope from the current travel speed to the target travel speed. As a result, the driving speed of the forklift can be prevented from being drastically reduced, so that the forklift can be driven more safely.

On the other hand, the deceleration slope may have a gentle slope initially and a sharp slope later. As a result, the driving speed of the forklift can be initially reduced to a moderate speed while the deceleration is in progress, thereby preventing safety accidents caused by sudden deceleration, and shortening the time to reach the target driving speed when decelerating in the reduced speed state. can do.

Hereinafter, the inclination of the mast frame in the forklift control method according to an embodiment of the present invention will be described with reference to the accompanying drawings. Accompanying drawings, Figure 3 is a flow chart for explaining an example of controlling the inclination of the mast frame in the forklift control method according to an embodiment of the present invention.

When the operator judges that the safe state is clear, there may be times when the inclination of the fork needs to be inclined further. In other words, the present invention is to be able to meet the requirements of the operator more.

Hereinafter, the control of the mast tilting in the control method of the forklift according to the present invention will be described step by step.

Fifth step S20: The fifth step is a step in which a tilting operation of the mast is required. The mast is configured to include a mast frame 10, a lift frame 12, a lift actuator 30, and a fork 40. The tilting actuator 50 is expanded or retracted by hydraulic pressure, when the mast is inclined to the front of the forklift when it is expanded, and the mast is inclined toward the rear of the forklift when it is retracted.

The operation of the tilting actuator 50 is made by the operation of the operation unit 63. Controlling the operation unit 63 generates a tilting pilot signal, which is provided to the control valve 62. The spool of the control valve 62 moves in accordance with the tilting pilot signal. As the spool of the control valve 62 moves, the hydraulic oil discharged from the hydraulic pump 61 is provided to the tilting actuator 50, and in particular, the flow rate of the hydraulic oil and the flow direction of the hydraulic oil are determined.

That is, the mast tilting operation is required to mean that the operator operated the operation unit 63.

Sixth Step (S22): The sixth step is a step of determining whether the slope of the mast frame reaches a set slope.

The inclination detection sensor 74 is provided in the mast, and the automatic tilting switch 80 is provided in the cab of the forklift. If the tilting of the mast is required to operate when the automatic tilting switch 80 is turned on, the tilt of the mast is changed, and when the mast is detected by the tilt detection sensor 74, the tilt of the mast is detected in more detail. It can be determined that has been reached.

The mast has a direction of inclination from the rear to the front (see a) and a direction of inclination from the front to the rear (see b). By tilting the mast, it is possible to set a specific position, ie the tilt of the mast, in which direction the mast moves.

Seventh Step (S24): The seventh step is a step in which the tilting operation of the mast is stopped when the inclination of the mast frame reaches a set slope. As described above, when the mast is detected by the inclination detection sensor 74 when the mast is tilted, the mast is determined to have reached the set slope, and even though the operator is operating the control unit 63, the control valve ( The tilting pilot signal provided to 62 is interrupted to stop the tilting actuator 50 from operating.

This makes it possible to set the slope of the mast in a more stable state without depending on the sixth sense of the operator.

Eighth Step S26: After the tilting operation of the mast is stopped, the tilting operation of the mast is additionally required. Since the prevention of safety accidents is a top priority, the set slope described above can be set very conservatively. However, there are cases where the position where the mast is automatically stopped is not suitable at the actual work site. In other words, it is sometimes necessary to tilt the mast more forward.

In this case, the operator may manually request the tilting operation of the mast by manually operating the operation unit 63.

Ninth Step (S28): In the ninth step, it is determined whether the automatic tilting switch 80 is deactivated. As described above, even if the tilting operation of the mast is additionally required by the operator, when the automatic tilting switch 80 is turned on, the tilting actuator is not transmitted to the control valve 62 even when the operation unit 63 is operated. 50 does not work. Therefore, it is to determine whether the operation of the automatic tilting switch 80 is released.

Step 10 (S30): If the operation of the automatic tilting switch 80 is released, step 10 is a step in which a required tilting operation of the mast is performed. That is, after the automatic tilting switch 80 is switched off, the tilting operation of the mast is performed. In detail, when turning off the automatic tilting switch 80 while operating the operation unit 63, the tilting operation of the mast is performed.

This allows the operator to call attention when performing the tilting operation of the mast, thus preventing the tilting of the mast from being arbitrarily carried out, and nevertheless masting more carefully when it is deemed necessary to perform additional tilting of the mast. It will perform the tilting operation of.

On the other hand, the above-described inclination of the mast may be a slope inclined 2 degrees toward the front of the forklift based on the horizontal line.

That is, in the case where the height of the fork 40 or the lift frame 12 is as high as the set height, even if the tilting operation of the mast is required, the tilting operation is more than the set inclination. Therefore, the control method of the forklift according to the present invention can prevent the mast from excessively inclining in the foreground direction (see a) in the state of raising the cargo to a high position, thereby preventing the cargo from falling.

On the other hand, the set slope can be changed according to the friction coefficient between the fork and the pallet and the weight of the cargo mounted on the fork.

On the other hand, the present invention includes a control unit 100, the control unit 100 receives the detection signal from the height detection sensor 72 and the tilt detection sensor 74 determines whether the target traveling speed and the set slope has been reached. In addition, a control signal for decelerating to a traveling system (transmission, etc.) may be sent, or a tilt pilot signal may be controlled to be provided to or blocked from the control valve 62.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art to which the present invention departs from the gist of the present invention as claimed in the claims. Of course, such changes will fall within the scope of the claims.

The control method of the forklift according to the present invention can be used to limit the traveling speed when the mast height is high so as to drive the forklift.

10: mast frame 12: lift frame

20: lift actuator 22: wheel

30: chain

40: fork 50: tilt actuator

61: hydraulic pump 62: control valve

63: control panel

72: height detection sensor 74: tilt detection sensor

80: automatic tilting switch 100: control unit

Claims

First step (S10) that the lifting of the fork is controlled;

A second step (S12) in which the height of the fork is determined;

A third step (S16) of determining whether the required traveling speed is faster than a target traveling speed when the height of the fork is equal to or higher than the set height; And

A fourth step (S18) of controlling the driving speed of the forklift to decelerate to the target traveling speed when the required traveling speed is faster than the target traveling speed;

Control method of the forklift comprising a.
The method of claim 1,

Step 3-1 (S14) in which the forklift is controlled to travel at a required traveling speed when the height of the fork is lower than a set height;

Control method of the forklift comprising a further.
The method of claim 1,

If the height of the fork is equal to or higher than the set height, the control method of the forklift, characterized in that the deceleration with the deceleration slope from the current traveling speed to the target traveling speed.
The method of claim 3,

The control method of the forklift, characterized in that the deceleration slope has a gentle slope initially, a sharp slope later.
The method according to any one of claims 1 to 4,

A fifth step (S20) requiring tilting of the mast;

A sixth step (S22) of determining whether a slope of the mast frame reaches a set slope;

A seventh step (S24) of stopping the tilting operation of the mast when the inclination of the mast frame reaches a set slope;

An eighth step (S26) in which a tilting operation of the mast is additionally required after the tilting operation of the mast is stopped;

A ninth step S28 in which it is determined whether the automatic tilting switch is deactivated; And

A tenth step (S30) in which a tilting operation of a required mast is additionally performed if the automatic tilting switch is released;

Control method of the forklift comprising a further.
The method of claim 5,

The set slope is a forklift control method characterized in that the inclination inclined 2 degrees toward the front of the forklift based on the horizontal line.