JP2001226096A - Overturning alarm device and safety device against overturning for industrial vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an overturning alarm device and a safety device against overturning for an industrial vehicle for efficient cargo handling work. SOLUTION: This overturning alarm device for the industrial vehicle, which loads a cargo with a cargo handling machine installed in the front of a car body and travels, and alarms braking to an operator to prevent overturning, is equipped with a speed detector 13 for detecting car speed; state detectors 11, 12, 26 for detecting the state amount influencing the overturning of the vehicle; a speed operating part 32 calculating the present car speed based on a detected signal from the car speed detector 13; allowable car speed operating parts 33a1, 33a2 in which the maximum value of braking start car speed at which the vehicle does not tip in the front when braking by the specified braking force is applied based on the vehicle state is set as an allowable car speed, for calculating the allowable car speed based on a detected signal from the state detectors 11, 12, 26; and comparing parts 34a, 34b for judging the possibility of front overturning of the vehicle by comparing the allowable car speed with the present car speed and for operating alarms 24a, 24b based on the judgment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fall warning device and a fall prevention device for an industrial vehicle such as a forklift.

[0002]

2. Description of the Related Art As shown in FIG. 20, a forklift, which is an industrial vehicle, has a pair of left and right forks 57, 57 mounted on a front portion of a vehicle body 52 so as to be vertically movable and tiltable. The vehicle can be driven by the rear wheel 59. If sudden braking is applied while the vehicle is traveling with a load loaded on the fork 57, the forklift may fall forward with the axle P of the front wheel 58 as a fulcrum. In particular, in the case of sudden braking during high-speed running with a high lift, the possibility of falling forward increases. That is, as shown in FIG. 20, the front wheel 58 bends due to the braking acceleration and the rear wheel 59 floats, and the combined center of gravity G of the vehicle and the load comes out of the vertical plane V including the front axle P, thereby causing the vehicle to fall. It will arrive.

A device for preventing a fall due to the sudden braking is as follows.
It is disclosed in Japanese Patent Application Laid-Open No. 9-76891. That is, an allowable brake pressure capable of obtaining the maximum braking force without falling down is calculated from the center of gravity position and the braking acceleration obtained from each information of the vehicle, and the brake pressure by the operation of the operator is controlled to be equal to or less than the allowable brake pressure. To prevent falling.

[0004]

However, in the overturn prevention device disclosed in Japanese Patent Application Laid-Open No. 9-76891, the braking force is limited to prevent the overturn, so that the braking distance becomes long, and the operator's braking distance increases. There is a case where the target stop position is exceeded, which is not preferable. For this reason, the vehicle travels at an unnecessarily low vehicle speed, and the cargo handling efficiency is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide an industrial vehicle overturn warning device and overturn prevention device which can efficiently carry out cargo handling work.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention is directed to loading and running a load by a loading / unloading machine provided in front of a vehicle body and preventing the vehicle from tipping over during braking. An industrial vehicle fall warning device that alerts an operator includes a vehicle speed detector that detects a vehicle speed, a state detector that detects a state quantity that affects the vehicle overturn, and a current vehicle speed based on a detection signal from the vehicle speed detector. And a maximum value of a braking start vehicle speed that does not fall forward when braking with a predetermined braking force is applied according to the vehicle state is set as an allowable vehicle speed, and the maximum value is set based on a detection signal from the state detector. An allowable vehicle speed calculating unit for calculating the vehicle speed, and a comparing unit that compares the allowable vehicle speed with the vehicle speed to determine whether there is a possibility of the vehicle falling over, and activates an alarm based on the determination. Features .

According to the above configuration, according to the state of the vehicle,
The maximum speed at which the vehicle can be stopped without falling over during sudden braking, that is, the allowable vehicle speed is appropriately calculated, and when the vehicle speed exceeds the calculated allowable vehicle speed, a warning is given that there is a risk of a front fall. Correspondingly, it can run at the maximum speed according to the vehicle state. At this time, even when sudden braking is applied, the vehicle can be reliably stopped with the maximum braking force. Therefore, the work can proceed efficiently.

In the present invention, the allowable vehicle speed calculating section may include a detection signal from a lift detector for detecting a lift of the working machine loading the load, and a detection signal from a load detector for detecting the load of the load. And calculating a permissible vehicle speed signal based on the detection signal from the rear axle load detector.

[0009] According to the above configuration, the rear axle load has a close relationship with the overturning moment that directly indicates the possibility of a forward fall, and by detecting the rear axle load, an appropriate load corresponding to the vehicle state is obtained. It is possible to calculate a permissible vehicle speed, and to appropriately notify. Therefore, the work efficiency can be improved without narrowing the allowable range such as the workable range and the work speed limit more than necessary.

[0010] The allowable vehicle speed calculating section includes a detection signal from a lift detector for detecting a lift of a work machine for loading the load, a detection signal from a load detector for detecting a load of the load, and a load signal. The allowable vehicle speed signal may be calculated based on a detection signal from a tilt cylinder pulling force detector that detects a pulling force applied to a tilt cylinder that tilts the work machine on which the work is loaded.

According to the above structure, the tilt cylinder pulling force has a close relationship with the overturning moment which directly indicates the possibility of the vehicle tipping over. The appropriate permissible vehicle speed can be calculated, and an appropriate notification can be made. Therefore, the work efficiency can be improved without narrowing the allowable range such as the workable range and the work speed limit more than necessary.

[0012] The allowable vehicle speed calculating section may be configured to detect a lift of a working machine loading the load from a lift detector and a load detector for detecting a load of the load. Alternatively, the allowable vehicle speed signal may be calculated.

According to the above configuration, the allowable vehicle speed is simply calculated from the lift and the load of the load, so that the number of detection sensors used is small and the arithmetic processing is simplified, and the cost (the cost of development, production and maintenance) is reduced. A cheap fall alarm device can be obtained.

Further, the present invention relates to an overturn prevention device for an industrial vehicle which runs while loading a load by a loading and unloading machine provided in front of the vehicle body and prevents the overturn when braking the running.
A state detector that detects a state quantity that affects a vehicle overturn,
The maximum value of the braking start vehicle speed that does not fall forward when the vehicle is braked by the predetermined braking force according to the vehicle state is set as the allowable vehicle speed, and the allowable vehicle speed calculation unit calculates the allowable vehicle speed based on the detection signal from the state detector. And a vehicle speed limiting unit that outputs a vehicle speed limiting signal based on the allowable vehicle speed signal so as not to exceed the calculated allowable vehicle speed and limits the vehicle speed.

According to the above configuration, according to the state of the vehicle,
Appropriately calculates the maximum speed that can be stopped without falling over during sudden braking, that is, the allowable vehicle speed, and limits the vehicle speed so that it does not exceed the calculated allowable vehicle speed. Can be stopped immediately, and a fall can be prevented. Therefore, it is possible to travel at the maximum speed according to the vehicle state, and it is possible to carry out cargo handling efficiently.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view of a forklift to which the present invention is applied. A work machine 1 of a forklift is mounted on a front part of a vehicle body 2.
The work machine 1 includes a pair of left and right masts 4, 4 mounted to be tiltable with respect to the vehicle body 2 by a tilt cylinder 3 disposed between the work machine 1 and the front part of the vehicle body 2, and a lift cylinder 5 along the mast 4. The finger board 6 is attached to the finger board 6 so as to be able to move up and down, and a pair of left and right forks 7, 7 attached to the finger board 6.

An operator's cab 21 of the vehicle body 2 on which the front wheels 8 and the rear wheels 9 are mounted is provided with an operating device 22 such as a steering wheel, an instrument panel 23 to which instruments and monitors are attached. A lift sensor 11 and a pressure sensor 12 are mounted on the lift cylinder 5. The lift sensor 11 measures the extension of the lift cylinder 5 to detect the lift position of the fork 7. As the lift sensor 11, for example, a potentiometer, an encoder, a pulse generator, or the like that detects elongation of a wire wound on a reel by rotation of the reel can be used.
The pressure sensor 12 detects the pressure of the bottom chamber of the lift cylinder 5 to calculate the load of the load L loaded on the fork 7. In addition, the pressure sensor 12 may detect the pressure of the hydraulic piping on the bottom side of the lift cylinder 5. A vehicle speed sensor 13 is provided on the axle of the front wheel 8.
Is installed. Examples of the vehicle speed sensor 13 include an electromagnetic pickup and a tachogenerator.

When the vehicle is stopped or traveling at a constant speed, the center of gravity G0 of the combined load M of the center of gravity G1 of the vehicle and the center of gravity G2 of the load L loaded on the fork 7 is usually the axis of the front wheel 8, as shown in FIG. However, if the load of the load L is heavy or the mast 4 is tilted forward in a state where the lift is high, the combined center of gravity G0 moves forward. Since the moment in the clockwise direction in the figure due to the combined load around the front axle P is reduced, the vehicle can easily fall forward around the front axle P. Hereinafter, the moment due to the combined load M on the front axle P that directly indicates the possibility of the front fall when the vehicle is stopped or traveling at a constant speed is referred to as a fall moment.

FIG. 2 is a diagram for explaining a forward fall caused by the braking force F. When the moment around the front axle P due to the braking force F (F × LF) becomes larger than the moment around the front axle P due to the combined load M (M × LM), that is, the overturning moment, the center of gravity G0 is centered around the front axle P. When the center of gravity G0 starts to move forward from the vertical plane V including the front axle P, the vehicle falls down. Also, if braking is completed before the center of gravity G0 exceeds the vertical plane V, overturning can be avoided.

The maximum value of the braking start vehicle speed when the braking ends by the braking force F before the center of gravity G0 exceeds the vertical plane V is called an allowable vehicle speed at the braking force F. In other words, this means a set vehicle speed at which the vehicle does not fall forward even when braking is applied by the braking force F while traveling at a speed lower than the allowable vehicle speed. By the way, from the moment of the center of gravity G0 obtained from the state quantity representing the state of the vehicle affecting the fall during braking and the predetermined braking force F stored in advance, the center of gravity G0 is shifted to the vertical plane V after the rear wheel 9 starts to float. The permissible vehicle speed can be obtained by calculating the time until the vehicle reaches the vehicle and multiplying the braking acceleration by the time. In the embodiment of the present invention, for a predetermined braking force, the relationship between the state quantity of the vehicle and the allowable vehicle speed obtained as described above is set in advance as a map, and each parameter for the state of the vehicle is set. , The allowable vehicle speed is calculated, and the calculated allowable vehicle speed is compared with the current vehicle speed to determine whether there is a possibility of the vehicle falling over.

FIG. 3 is a block diagram showing a fall alarm device according to the first embodiment of the present invention. The controller 30a
For example, it is mainly configured by an arithmetic processing unit such as a microcomputer or a numerical processor, and has a vehicle speed calculating unit 32, allowable vehicle speed calculating units 33a1, 33a2, and comparing units 34a, 34b. The controller 30a is connected to the lift sensor 11, the pressure sensor 12, the rear axle load sensor 26, and the vehicle speed sensor 13 as state detectors, and is connected to an alarm having, for example, lamps 24a and 24b. ing.

As shown in FIG. 4, the rear axle load sensor 26 supports the center pin 16 of the axle 15 of the rear wheel 9 and is a strain gauge attached to a bracket 17 attached to the frame 14 of the vehicle body 2. is there. The lamps 24 a and 24 b are mounted on the instrument panel 23 of the cab 21.

Next, the operation of the above configuration will be described. Lift sensor 11, pressure sensor 12, and rear axle load sensor 2
The respective detection signals of the lift, the load of the load and the rear axle load from 6 are input to the permissible vehicle speed calculation units 33a1 and 33a2, respectively.

As shown in FIG. 5, the permissible vehicle speed calculating section 33a1 calculates the permissible vehicle speed when gentle braking (for example, a braking force of about two-thirds is obtained with respect to braking force by rapid braking). A plurality of maps to be obtained are calculated and stored in advance as warning level maps by calculation or experiment. That is, a predetermined lift (for example,
Height 0 m) and a predetermined load (for example, load 0.
5t), a map showing the relationship between the rear axle load Wr and the permissible vehicle speed at the time of gentle braking is determined by a predetermined lift interval (for example, 1
(m intervals) and predetermined load intervals (for example, 0.5t intervals) are stored in a matrix. Then, the permissible vehicle speed calculation unit 33a1 calculates the permissible vehicle speed in gentle braking by interpolating data from the input detection signals of the lift, the load of the load, and the rear axle load, and outputs this to the comparison unit 34a. Similar to the allowable vehicle speed calculation unit 33a1, the allowable vehicle speed calculation unit 33a2 stores a plurality of maps for obtaining the allowable vehicle speed when sudden braking is applied, which are obtained in advance by calculations or experiments as maps of the caution level. ing. Then, the allowable vehicle speed calculation unit 33a2 calculates the lift, the load of the load, and the rear axle load from the input detection signals.
The data is interpolated to calculate the permissible vehicle speed in sudden braking, and output this to the comparison unit 34b. If the vehicle conditions are the same, the permissible vehicle speed in sudden braking is lower than the permissible vehicle speed in gentle braking.

The vehicle speed calculation unit 32 calculates the current vehicle speed based on the detection signal from the vehicle speed sensor 13 and outputs the current vehicle speed to the comparison units 34a and 34b. The comparison unit 34a compares the input permissible vehicle speed for gentle braking with the current vehicle speed, and when the vehicle speed is higher than the permissible vehicle speed, determines that the vehicle has reached the forward fall warning area and outputs the ON signal to the ramp 24a ( (For example, red). Similarly, the comparing unit 34b compares the allowable vehicle speed in the input sudden braking with the current vehicle speed, and when the vehicle speed is higher than the allowable vehicle speed, determines that the vehicle has reached the attention area of the front fall and outputs the ON signal. Lamp 24b (for example, yellow)
Output to

By setting an allowable vehicle speed map of a warning level (previous overturning due to gentle braking) in the allowable vehicle speed calculating section 33a1, when the current vehicle speed exceeds the allowable vehicle speed, the red lamp 24a is turned on and the operator is notified of the current vehicle speed. It can be notified that the cargo handling operation at the vehicle speed of the vehicle is at the warning level. Similarly, by setting an allowable vehicle speed map of the caution level (falling forward due to sudden braking) in the allowable vehicle speed calculation unit 33a2,
When the current vehicle speed exceeds the allowable vehicle speed, the yellow lamp 24b is turned on, so that the operator can be notified that the cargo handling operation at the current vehicle speed is at the caution level.

The rear axle load Wr is proportional to the overturning moment (M × LM) which directly indicates the possibility of forward overturning.
It can also detect the effects of tilt angle, the position of the center of gravity of the cargo (front and rear, up and down), the inclination of the road surface in the front and rear directions, tire deflection, etc., so that an appropriate permissible vehicle speed can be calculated and used for alarm judgment processing. it can. Thereby, an appropriate warning can be received, and the working efficiency can be secured without narrowing the allowable range such as the workable range and the work speed limit by the warning more than necessary. Further, when an alarm is received, the allowable vehicle speed is increased by lowering the vehicle speed or lowering the lift so that the cargo handling work can be continued while avoiding the alarm state. In addition, since the operator is notified of the possibility of a fall in front of the cargo handling operation at the current vehicle speed at a plurality of warning levels, the operation is performed by an operation according to the warning level (for example, sudden braking is not applied at the caution level). be able to. Therefore, before the vehicle reaches the front fall, the operator can accurately recognize whether or not the vehicle is likely to fall forward due to braking, and the vehicle can run at the maximum speed that can be run in the current vehicle state, Work efficiency can be improved. Also,
By driving within the allowable vehicle speed, the braking distance can be shortened.

FIG. 6 is a block diagram showing a fall alarm device according to a second embodiment of the present invention. The controller 30b includes:
Similar to the controller 30a, it is mainly composed of an arithmetic processing unit,
The vehicle includes a vehicle speed calculation unit 32, allowable vehicle speed calculation units 33b1, 33b2, comparison units 34a, 34b, and a tilt cylinder tension force calculation unit 35. The controller 30b is connected to the elevation sensor 11, pressure sensors 12, 28a, 28b, and the vehicle speed sensor 13 as state detectors.
An alarm having a and 24b is connected.

As shown in FIG. 7, the pressure sensors 28a and 28b are pressure sensors 28a for detecting rod pressure in a pipe connecting the tilt operation valve 19 and the rod side of the tilt cylinder 3.
However, a pressure sensor 28b for detecting a bottom pressure is provided in a pipe connecting the tilt operation valve 19 and the bottom side of the tilt cylinder 3. The lamps 24 a and 24 b are mounted on the instrument panel 23 of the cab 21.

Next, the operation of the above configuration will be described. The detection signals of the lift and the load of the load from the lift sensor 11 and the pressure sensor 12 are output from the allowable vehicle speed calculation units 33b1 and 33b, respectively.
Input to 3b2. Further, the tilt cylinder tensile force calculation unit 35, which has received the detection signals of the rod pressure and the bottom pressure of the tilt cylinder 5 from the pressure sensors 28a and 28b, uses the differential pressure between the rod pressure and the bottom pressure to calculate the tilt cylinder tension. The force Ft is calculated, and the calculated value is output to the allowable vehicle speed calculation units 33b1 and 33b2, respectively.

As shown in FIG. 8, a plurality of maps for obtaining an allowable vehicle speed when gentle braking is applied are calculated and stored in advance in the allowable vehicle speed calculating section 33b1 as warning level maps by calculation or experiment. ing. That is, the map showing the relationship between the tilt cylinder tensile force Ft and the permissible vehicle speed during gentle braking at a predetermined lift (for example, a lift of 0 m) and a predetermined load (for example, a load of 0.5 t) in the vehicle state quantity. Is a predetermined height interval (for example, 1 m interval)
And at predetermined load intervals (for example, 0.5t intervals) in a matrix. The permissible vehicle speed calculation unit 33b1 calculates the permissible vehicle speed in gentle braking by interpolating the data from the input detection signals of the lift, the load of the load, and the tilt cylinder pulling force, and outputs this to the comparison unit 34a. . The permissible vehicle speed calculator 33b2 includes:
Similarly to the permissible vehicle speed calculation unit 33b1, a plurality of maps for obtaining the permissible vehicle speed when sudden braking is applied are obtained and stored in advance as maps of the caution level by calculation or experiments. The permissible vehicle speed calculation unit 33b2 calculates the permissible vehicle speed in sudden braking by interpolating the data from the input detection signals of the lift, the load of the load, and the tilt cylinder pulling force, and outputs this to the comparison unit 34b. .

The vehicle speed calculation unit 32 calculates the current vehicle speed based on the detection signal from the vehicle speed sensor 13 and outputs this to the comparison units 34a and 34b. The comparison unit 34a compares the input permissible vehicle speed for gentle braking with the current vehicle speed, and when the vehicle speed is higher than the permissible vehicle speed, determines that the vehicle has reached the forward fall warning area and outputs the ON signal to the ramp 24a ( (For example, red). Similarly, the comparing unit 34b compares the allowable vehicle speed in the input sudden braking with the current vehicle speed, and when the vehicle speed is higher than the allowable vehicle speed, determines that the vehicle has reached the attention area of the front fall and outputs the ON signal. Lamp 24b (for example, yellow)
Output to

In this embodiment, the differential pressure between the rod pressure of the tilt cylinder 3 and the bottom pressure is used to determine the tilt cylinder pulling force, but the strain gauge is attached to the rod of the tilt cylinder 3 to tilt. You may comprise so that a cylinder pulling force may be detected.

By setting a permissible vehicle speed map of a warning level (previous fall due to gentle braking) in the permissible vehicle speed calculation section 33b1, when the current vehicle speed exceeds the permissible vehicle speed, the red lamp 24a is turned on and the operator is notified of the current vehicle speed. It can be notified that the cargo handling operation at the vehicle speed of the vehicle is at the warning level. Similarly, by setting an allowable vehicle speed map of the caution level (falling forward due to sudden braking) in the allowable vehicle speed calculation unit 33b2,
When the current vehicle speed exceeds the allowable vehicle speed, the yellow lamp 24b is turned on, so that the operator can be notified that the cargo handling operation at the current vehicle speed is at the caution level.

The moment due to the tilt cylinder pulling force Ft is the difference between the overturning moment, which directly indicates the possibility of a forward fall, and the moment due to the vehicle load, and includes the tilt angle, the position of the center of gravity of the load (front and rear, up and down), and the road surface. Since the influence of the inclination in the front-rear direction, the deflection of the tire, and the like can also be detected, an appropriate allowable vehicle speed can be calculated, and this can be used for the alarm determination process. Thereby, an appropriate warning can be received, and the working efficiency can be secured without narrowing the allowable range such as the workable range and the work speed limit by the warning more than necessary. Further, when an alarm is received, the allowable vehicle speed is increased by lowering the vehicle speed or lowering the lift so that the cargo handling work can be continued while avoiding the alarm state. In addition, since the operator is notified of the possibility of a fall in front of the cargo handling operation at the current vehicle speed at a plurality of warning levels, the operation is performed by an operation according to the warning level (for example, sudden braking is not applied at the caution level). be able to. For this reason,
It is possible to obtain an overturn alarm device that can make the operator properly recognize whether or not the vehicle is likely to fall forward and that can improve work efficiency.

FIG. 9 is a block diagram showing a fall alarm device according to a third embodiment of the present invention. The controller 30c
Similar to the controller 30a, it is mainly composed of an arithmetic processing unit,
It has a vehicle speed calculation unit 32, allowable vehicle speed calculation units 33c1, 33c2, and comparison units 34a, 34b. The controller 30c includes a height sensor 11 and a pressure sensor 12 as state detectors.
And the tilt angle sensor 29 and the vehicle speed sensor 13 are connected,
Further, for example, an alarm having lamps 24a and 24b is connected.

The tilt angle sensor 29 is, for example, a potentiometer mounted on the mast 4. An encoder may be used instead of the potentiometer. Instead of directly detecting the tilt angle of the mast 4, the extension of the tilt cylinder 3 may be detected and converted into a tilt angle. Lamp 24a,
Reference numeral 24b is mounted on the instrument panel 23 of the cab 21.

Next, the operation of the above configuration will be described. Lift sensor 11, pressure sensor 12, and tilt angle sensor 29
The respective detection signals of the lift, the load of the load, and the tilt angle are input to the permissible vehicle speed calculation units 33c1, 33c2.

As shown in FIG. 10, a plurality of maps for obtaining the allowable vehicle speed when gentle braking is applied are calculated and stored in advance in the allowable vehicle speed calculating section 33c1 as warning level maps by calculation or experiment. ing. That is, among the vehicle state quantities, a map showing the relationship between the load load at a predetermined height (for example, a height of 0 m) and a predetermined tilt angle (for example, a tilt angle of 6 °) and the allowable vehicle speed at the time of gentle braking is a predetermined value. The information is stored in a matrix corresponding to every elevation interval (for example, 1 m interval) and each predetermined tilt angle interval (for example, 6 ° interval). Then, the allowable vehicle speed calculation unit 33c1
Based on the input detection signals of the lift, the load of the load, and the tilt angle, data is interpolated to calculate an allowable vehicle speed in gentle braking and output this to the comparison unit 34a. Similar to the allowable vehicle speed calculation unit 33a1, the allowable vehicle speed calculation unit 33c2 stores a plurality of maps for calculating the allowable vehicle speed when sudden braking is applied, which are obtained in advance by calculations or experiments, etc., as caution level maps. ing. The permissible vehicle speed calculation unit 33c2 calculates the permissible vehicle speed in sudden braking by interpolating the data from the input detection signals of the lift, the load of the load, and the tilt angle, and outputs the calculated permissible vehicle speed to the comparison unit 34b.

The vehicle speed calculation unit 32 calculates the current vehicle speed based on the detection signal from the vehicle speed sensor 13 and outputs the current vehicle speed to the comparison units 34a and 34b. The comparison unit 34a compares the input permissible vehicle speed for gentle braking with the current vehicle speed, and when the vehicle speed is higher than the permissible vehicle speed, determines that the vehicle has reached the forward fall warning area and outputs the ON signal to the ramp 24a ( (For example, red). Similarly, the comparing unit 34b compares the allowable vehicle speed in the input sudden braking with the current vehicle speed, and when the vehicle speed is higher than the allowable vehicle speed, determines that the vehicle has reached the attention area of the front fall and outputs the ON signal. Lamp 24b (for example, yellow)
Output to

By setting an allowable vehicle speed map of a warning level (falling forward due to gentle braking) in the allowable vehicle speed calculation section 33c1, the red lamp 24a is turned on when the current vehicle speed exceeds the allowable vehicle speed, and the operator is notified of the current vehicle speed. It can be notified that the cargo handling operation at the vehicle speed of the vehicle is at the warning level. Similarly, by setting an allowable vehicle speed map of the caution level (falling forward due to sudden braking) in the allowable vehicle speed calculator 33c2,
When the current vehicle speed exceeds the allowable vehicle speed, the yellow lamp 24b is turned on, so that the operator can be notified that the cargo handling operation at the current vehicle speed is at the caution level.

Compared with the first and second embodiments, the tilt angle sensor 29 cannot detect the influence of the position of the center of gravity of the load (front and rear, up and down), the inclination of the road surface in the front and rear direction, the deflection of the tire, and the like. However, it is possible to simply calculate the allowable vehicle speed and use this in the alarm determination process. Furthermore, if the vehicle has an automatic fork leveling function, the cost can be reduced because the tilt angle sensor 29 can be shared. Further, when an alarm is received, the allowable vehicle speed is increased by lowering the vehicle speed or lowering the lift so that the cargo handling work can be continued while avoiding the alarm state. In addition, since the operator is notified of the possibility of a fall in front of the cargo handling operation at the current vehicle speed at a plurality of alarm levels, the operation according to the alarm level (for example,
At the caution level, do not apply sudden braking). For this reason, the operator can accurately recognize whether or not the vehicle is likely to fall forward, and a fall warning device that can improve work efficiency can be obtained.

FIG. 11 is a block diagram showing a fall warning device according to another embodiment of the third embodiment of the present invention. That is, the tilt angle sensor 29 is omitted in order to obtain the allowable vehicle speed more easily.

For this reason, for example, as shown in FIG. 12, the allowable vehicle speed calculation unit 33d1 obtains a plurality of maps for obtaining the allowable vehicle speed when gentle braking is applied as warning level maps by calculation or experiment in advance. Is stored. That is, a predetermined lift (for example,
Lift height 0m) and the mast forward leaning end (for example, tilt angle 6
The map showing the relationship between the load load in (°) and the permissible vehicle speed at the time of gentle braking is stored for each predetermined lifting interval (for example, every 1 m). The reason for selecting the map at the forward inclined end of the mast 4 is to obtain an allowable vehicle speed on the safe side.
The permissible vehicle speed calculation unit 33d1 calculates the permissible vehicle speed in gentle braking by interpolating the data based on the input detection signals of the lift and the load of the load, and compares this with the comparison unit 34a.
Output to

By adopting a configuration in which the tilt angle sensor 29 is omitted, although the accuracy is slightly lowered, the permissible vehicle speed can be obtained more easily, and a fall alarm device with low cost can be obtained.

Further, in order to obtain the allowable vehicle speed more simply, it is possible to omit the height sensor 11 and the pressure sensor 12. FIG. 13 is a block diagram showing the configuration applied to the first embodiment, and FIG. 15 is a block diagram showing the configuration applied to the second embodiment. At this time, for example, as shown in FIG. 14, the allowable vehicle speed calculation unit 33e1 obtains a map indicating the relationship between the allowable vehicle speed and the rear axle load when the gentle braking is applied as a warning level map by calculation or experiment in advance. It is remembered. Similarly, as shown in FIG. 16, the allowable vehicle speed calculation unit 33f1 obtains a map indicating the relationship between the tilt cylinder tensile force and the allowable vehicle speed when gentle braking is applied as a warning level map by calculation or experiment in advance. It is remembered. Thus, with a simple configuration in which the height sensor 11 and the pressure sensor 12 are omitted, although the accuracy is slightly lowered, the permissible vehicle speed can be more easily obtained, and a fall alarm device with low cost can be obtained.

In the embodiment, the lamps 24a and 24b are
Although described in the example of being attached to the instrument panel 23, it may be attached to the mast 4 or the front stay of the head guard with good visibility for the operator during work. Also, the red lamp 24
In the example described above, the yellow lamp 24b is also turned on when a is turned on. However, as shown in FIG. 17, for example, as shown in FIG.
May be configured to turn off the yellow lamp 24b when is turned on. Also, as shown in FIG.
a and 25b may be provided side by side. In this case, the pattern of the alarm sound (for example, difference in volume, difference in timbre, difference between continuous sound and intermittent sound, etc.) is provided according to the alarm level. What is necessary is just to make an operator recognize an alarm level. Further, the alarm level has been described in two stages (attention level and warning level), but an alarm level of only one stage may be used. Also, three or more alarm levels may be provided and used as a level indicator using a lamp array. Either the lamp or the buzzer may be used as the alarm.

Further, instead of the height sensor 11, a plurality of switches may be used to detect the height.
It is desirable to provide a switch so that a lift corresponding to a predetermined lift in the map stored in the permissible vehicle speed calculator 33 can be detected. At this time, at an intermediate lift, the allowable vehicle speed may be obtained from a map of the lift on the higher side, which is a safe side, as an alarm device. Note that the switches include limit switches and reed switches.

In the above-described embodiment, the fall warning device that warns that there is a risk of a front fall by comparing the allowable vehicle speed with the current vehicle speed has been described.
By providing the vehicle speed limiter, a fall prevention device can be obtained.

That is, as shown in FIG.
0g adds an engine rotation limiting unit 36 as a vehicle speed limiting unit to the controller 30a of the first embodiment. The engine rotation limiting unit 36 receives a signal from the allowable vehicle speed calculating unit 33a1 for calculating the warning level allowable vehicle speed signal, and generates an engine rotation limiting signal based on the input warning level allowable vehicle speed signal so as not to exceed the allowable vehicle speed. The calculated value is output to the electronic governor controller 46. Further, as shown in FIG. 19, the alarm function is omitted, and the controller 30h sets the allowable vehicle speed calculation unit 33a.
A fall prevention device that limits the vehicle speed with a configuration including the engine rotation restriction unit 1 and the engine rotation restriction unit 36 may be used. In a vehicle having a multi-speed transmission, a speed limiter is provided as a vehicle speed limiter instead of the engine rotation limiter 36 so that the vehicle speed does not exceed the allowable speed based on the input warning level allowable speed signal. (For example, if the vehicle has four forward speeds, it is limited to the second speed).

Further, the vehicle speed may be limited based on the caution level allowable vehicle speed signal from the allowable vehicle speed calculation unit 33a2 instead of the warning level allowable vehicle speed signal. As a result, the vehicle speed is restricted earlier at the stage of the vehicle speed lower than the warning level vehicle speed, so that it is possible to prevent the vehicle from tipping over even in the event of sudden braking.

As described above, according to the present invention, the allowable vehicle speed at the predetermined braking force is appropriately calculated from the state of the vehicle, and when the vehicle speed exceeds the calculated allowable vehicle speed, there is a possibility that the vehicle may fall forward. The operator can pay attention to the operation in response to the alarm and proceed with the operation safely. In addition, by receiving appropriate alarms,
The working efficiency can be ensured without narrowing the allowable range such as the workable range and the work speed limit by the alarm more than necessary. Furthermore, since the vehicle speed is limited so as not to exceed the allowable vehicle speed, it is possible to prevent the vehicle from falling forward even in the event of sudden braking.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an example of a forklift to which the present invention is applied.

FIG. 2 is a diagram illustrating a forward fall due to a braking force.

FIG. 3 is a block diagram of a first embodiment of the present invention.

FIG. 4 is a diagram illustrating a mounting state of the sensor according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of an allowable vehicle speed calculation unit according to the first embodiment of the present invention.

FIG. 6 is a block diagram of a second embodiment of the present invention.

FIG. 7 is a diagram illustrating a mounting state of a sensor according to a second embodiment of the present invention.

FIG. 8 is an explanatory diagram of an allowable vehicle speed calculation unit according to a second embodiment of the present invention.

FIG. 9 is a block diagram of a third embodiment of the present invention.

FIG. 10 is an explanatory diagram of an allowable vehicle speed calculator according to a third embodiment of the present invention.

FIG. 11 is a block diagram of another aspect of the third embodiment of the present invention.

FIG. 12 is an explanatory diagram of an allowable vehicle speed calculation unit according to another aspect of the third embodiment of the present invention.

FIG. 13 is a block diagram showing another aspect of the first embodiment of the present invention.

FIG. 14 is an explanatory diagram of an allowable vehicle speed calculation unit according to another aspect of the first embodiment of the present invention.

FIG. 15 is a block diagram showing another aspect of the second embodiment of the present invention.

FIG. 16 is an explanatory diagram of an allowable vehicle speed calculation unit according to another aspect of the second embodiment of the present invention.

FIG. 17 is a diagram illustrating another embodiment of the output unit of the controller according to the present invention.

FIG. 18 is a block diagram of a fourth embodiment of the present invention.

FIG. 19 is a block diagram showing another aspect of the fourth embodiment of the present invention.

FIG. 20 is a diagram illustrating a forklift according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Work machine, 2 ... Body, 3 ... Tilt cylinder, 4 ... Mast, 5 ... Lift cylinder, 6 ... Finger board, 7 ...
Fork, 8 front wheel, 9 rear wheel, 11 height sensor, 1
2, 28a, 28b: pressure sensor, 13: vehicle speed sensor, 2
2: Instrument panel, 24a, 24b: ramp, 26: rear axle load sensor, 29: tilt angle sensor, 30a, 30b, 3
0c, 30d, 30e, 30f, 30g, 30h: Controller, 3
2 ... Vehicle speed calculation unit, 33a1, 33a2, 33b1, 33b2, 3
3c1, 33c2, 33d1, 33d2, 33e1, 33e2, 33
f1, 33f2: allowable vehicle speed calculation unit, 34a, 34b: comparison unit,
35: tilt cylinder tensile force calculation unit; 36: engine rotation limit unit as a vehicle speed limit unit.

Claims (5)

[Claims] 1. An overturn warning device for an industrial vehicle that loads and runs a load by a loading and unloading machine provided in front of a vehicle body and alerts an operator during braking to prevent the vehicle from overturning, wherein a vehicle speed detector that detects a vehicle speed; A state detector that detects a state quantity that affects the vehicle overturning, a vehicle speed calculation unit that calculates a current vehicle speed based on a detection signal from the vehicle speed detector, and that braking with a predetermined braking force is applied according to the vehicle state. When the maximum value of the braking start vehicle speed that does not fall forward is set as the allowable vehicle speed, an allowable vehicle speed calculation unit that calculates the allowable vehicle speed based on the detection signal from the state detector, and compares the allowable vehicle speed with the vehicle speed A fall warning device for an industrial vehicle, comprising: a comparison unit that determines whether there is a possibility of a vehicle falling over and activates an alarm based on the determination. 2. The overturn warning device for an industrial vehicle according to claim 1, wherein the state detector includes a height detector that detects a height of a working machine that loads the load, and a load detection that detects a load of the load. And a rear axle load detector for detecting a load applied to a rear axle, the allowable vehicle speed calculation unit detects a signal from a height detector,
An overturn warning device for an industrial vehicle, wherein an allowable vehicle speed signal is calculated based on a detection signal from a load detector and a detection signal from a rear axle load detector. 3. The overturn warning device for an industrial vehicle according to claim 1, wherein the state detector includes a height detector that detects a height of a work implement that loads the load, and a load detection that detects a load of the load. And a tilt cylinder tensile force detector for detecting a tensile force applied to a tilt cylinder for tilting a work machine for loading a load forward and backward, the allowable vehicle speed calculating unit includes a detection signal from a height detector and ,
An overturn warning device for an industrial vehicle, wherein an allowable vehicle speed signal is calculated based on a detection signal from a load detector and a detection signal from a tilt cylinder tensile force detector. 4. The industrial vehicle overturn warning device according to claim 1, wherein the state detector includes a lift detector that detects a lift of a work implement that loads the load, and a load detector that detects a load of the load. A permissible vehicle speed calculation unit, a detection signal from a height detector,
A fall warning device for an industrial vehicle, wherein an allowable vehicle speed signal is calculated based on a detection signal from a load detector. 5. An overturning prevention device for an industrial vehicle that prevents a vehicle from overturning when the vehicle is loaded with a load by using a loading / unloading work machine provided in front of the vehicle body and braking the traveling, detects a state amount affecting the vehicle overturning. The maximum value of the braking start vehicle speed that does not fall forward when braking with a predetermined braking force is applied according to the vehicle state is set as the allowable vehicle speed, and the allowable vehicle speed is determined based on the detection signal from the state detector. An allowable vehicle speed calculating unit for calculating, and a vehicle speed limiting unit for outputting a vehicle speed limiting signal based on the allowable vehicle speed signal so as to prevent the vehicle speed from exceeding the calculated allowable vehicle speed and limiting the vehicle speed. Overturn prevention device for industrial vehicles.