JPH07144899A - Overturning preventing device for industrial vehicle - Google Patents

Abstract

PURPOSE:To avoid the occurrence of inclination of a car body due to puncture of a pneumatic tire and securely prevent the overturning of a vehicle and the fall of a load. CONSTITUTION:A pressure sensor 2 for detecting the air pressure is provided in each pneumatic tire 1, and a hydraulic cylinder (operating unit) 3 having a cylinder rod (support leg) 4, which can be freely projected downward of a car body by the operation of a switching valve (operating unit) 8, is provided in a car body. A cambered plate member (grounding unit) 5, which slides for contact with the road surface, is fitted to the lower end of the cylinder rod 4, and when the air pressure of the pneumatic tire 1 becomes a predetermined value or less on the basis of the detecting signal input from the pressure sensor 2, the cylinder rod 4 and the cambered plate member 5 are projected through the operation of the switching valve 8 by a control unit 10.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fall prevention device for industrial vehicles such as forklifts.

2. Description of the Related Art In a forklift equipped with pneumatic tires, if the tire is flattened during loading and unloading or running, the vehicle body may tilt toward the flattened side and fall, especially in the case of a vehicle with a high center of gravity such as a forklift. . Moreover, even if the vehicle does not fall, the load on the fork may drop due to the inclination of the vehicle body. Therefore, the actual development Sho-1
Japanese Patent No. 71704 discloses a fall prevention device for a forklift truck for preventing the occurrence of the above-mentioned problems. This fall prevention device forms a disc-shaped flange with a diameter slightly smaller than the outer diameter of the tire on the outer circumference of the brake drum attached to the axle hub together with the wheel,
When the tire is flat, the flange supports the vehicle body instead of the tire.

However, in the case of the above-described fall prevention device, since there is a difference in outer diameter between the flange and the tire, the flange supports the vehicle body on behalf of the tire when the tire is punctured. Then, the vehicle body is tilted toward the flat side by the difference in outer diameter. Therefore, it is difficult to say that it is possible to prevent the vehicle from falling or the load from falling. The present invention has been devised in view of the above circumstances, and solves the problem of avoiding the occurrence of leaning of a vehicle body due to a flat tire, and more reliably preventing the vehicle from falling or dropping a load. It should be an issue.

In order to solve the above-mentioned problems, the present invention is directed to an industrial vehicle equipped with a pneumatic tire, and a pressure sensor installed in each of the pneumatic tires for detecting an air pressure, and a lower end of which slides on the ground. When the air pressure of the pneumatic tire becomes less than or equal to a predetermined value based on a detection signal from the pressure sensor, a support leg that has a ground contact portion and is provided so as to project downwardly of the vehicle body, and an operation portion that operates the support leg. A new configuration is employed in which a control unit that causes the support leg to move in a projecting manner via the operation unit is provided. Further, as a preferred aspect of the present invention, the ground contact portion of the supporting leg may be formed of a sled plate member or a roller member.

In the fall prevention device of the present invention, the air pressure of each pneumatic tire is constantly detected by the pressure sensor, and the detection signal is input to the control unit. Then, when the pneumatic tire is punctured and the pneumatic pressure of the pneumatic tire decreases to a predetermined value, the control unit outputs a signal to the operating unit to instantaneously project the supporting leg and the grounding unit provided at the lower end thereof is grounded, It replaces flat tires and supports leaning car bodies in the early stages. As a result, the occurrence of a significant inclination of the vehicle body due to a flat tire is avoided, and the vehicle is securely prevented from tipping over or the loaded load is prevented from falling. Further, by forming the grounding portion of the support leg with the sled plate member, the sled plate member is surely grounded even when the road surface is uneven, and the stability is improved. Furthermore, by configuring the grounding portion of the supporting leg with a roller member,
The load applied to the supporting leg when supporting the vehicle body while the vehicle is traveling is reduced, and the durability is improved.

Embodiments of the present invention will now be described with reference to the drawings.
It (Embodiment 1) FIG. 1 schematically shows a fall prevention device according to this embodiment.
2 is a block diagram showing the configuration of the control unit according to the present embodiment.
It is a block diagram. In FIG. 1, 1 is a four-wheel fork truck
Pneumatic tires (left in Fig. 1) mounted on a vehicle (not shown)
Only the right front wheel is shown. ), And empty of each pneumatic tire 1
Pressure sensors 2 for detecting air pressure are respectively provided at the air supply ports.
It is provided. This pressure sensor 2 is empty of the pneumatic tire 1.
It is installed so that it can be displaced according to the atmospheric pressure.
An electrical signal that indicates the amount of displacement due to energization with (not shown)
Is output to the control unit 10 described later. 3 is left as an operating part
A pair of right hydraulic cylinders, below the vehicle body behind the front wheels
It is attached to the section. This hydraulic cylinder 3 is
Equipped with piston rod 4 as a support leg that expands and contracts toward
At the tip of each piston rod 4, there is a contact extending in the front-back direction.
A pair of left and right sled plate members 5 as the ground portion are attached.
It At the tip of each piston rod 4,
A guide member 4c for guiding and reinforcing the door 4 is fixed to the vehicle body.
Are arranged. Also, the tip of both piston rods 4
A part of the supporting leg is formed between the ends, and
An arm 6 for synchronizing the operation of the head 4 is connected.
The hydraulic cylinder 3 is a hydraulic circuit for loading and unloading the vehicle.
Hydraulic pump 7 as an operating unit connected to (not shown)
It is connected to the
Aoid type switching valve 8 is provided. This switching bar
The block 8 is controlled by a control signal output from the control unit 10 described later.
Oil passage from the hydraulic pump 7 to the hydraulic cylinder 3
Open up. 9 indicates to the operator that the pneumatic tire 1 is abnormal.
It is an alarm device that activates the alarm
And alarm buzzer. This alarm lamp and
The alarm buzzer is an electric signal output from the control unit 10 described later.
No. The control unit 10, as shown in FIG.
A memory 10a containing a program, a calculation means 10b,
Comparison means 10c, input / output interfaces 10d, 10e
It is composed of a microcomputer mainly
It The calculation means 10b is provided with an input interface from each pressure sensor 2.
Each based on the detection signal input through the face 10d
Time t _nPressure P of each pneumatic tire 1 at_nCalculate
And the air pressure decrease rate of each pneumatic tire 1 (ΔP / Δ
t) = (P₁-P₂) / (T₂-T₁) Processing
And each result is output to the comparison means 10c.
The comparing means 10c is the empty space calculated by the calculating means 10b.
Barometric pressure P₁Compare whether or not is smaller than the minimum air pressure Pmin
Setting process and air pressure decrease rate (ΔP / Δt)
Fixed air pressure decrease rate [ΔP / Δt]_OGreater than or not
The process of comparing and judging whether or not
Signal to the computing means 10b or the output interface 10
It outputs to the alarm device 9 and the switching valve 8 via e. Next
The operation of the fall prevention device of the present embodiment is shown in FIG.
Description will be given according to the flowchart of the section 10. First
In S31, initialization is executed by turning on the power source, and the hydraulic pressure is
The state where the piston rod 4 of the cylinder 3 is contracted to the top
Is set to the initial position of. In the next S32, the pressure sensor
2 based on the detection signal input to the calculating means 10b
t₁Pressure P of each pneumatic tire 1 at₁Is sought
It Then, in the next S33, the data is output from the calculation means 10b.
Pneumatic pressure P₁Based on the calculation result of
Air pressure P₁Determines whether is less than the minimum air pressure Pmin
To do. If the determination here is YES, either
It is determined that a flat tire has been punctured, and the
And activates the alarm device 9 and the switching valve
8 is activated. As a result, both hydraulic pressures from the hydraulic pump 7
By sending pressure oil to the cylinder 3, both pistons
The rod 4 instantaneously protruded and was attached to the tip
A flat tire with the left and right sled plate members 5 contacting the ground
It supports a leaning car body instead of 1. Note that the alarm
The operator who senses the operation of the device 9 operates the brakes, etc.
Perform the operation of as necessary. On the other hand, the determination in S33 is N
If it is O, the process proceeds to the next S34 and the pressure sensor 2 calculates it.
Based on the detection signal input to the means 10b, t₂Oke
Air pressure P of each pneumatic tire 1₂Is required. Next S3
In 5, the calculation means 10b (P₁-P₂) / (T₂-T
₁) To reduce the air pressure of each pneumatic tire 1
The rate (ΔP / Δt) is determined. And in the next S36
Is the air pressure decrease rate (ΔP
/ Δt), based on the calculation result of
Pressure decrease rate (ΔP / Δt) is [ΔP / Δt]_OGreater than
Or not. If the determination here is YES,
It is judged that a puncture has occurred in one of the pneumatic tires 1.
Then, the process jumps to S37 to operate the switching valve 8.
As a result, pressure oil is applied from the hydraulic pump 7 to both hydraulic cylinders 3.
The piston rod 4 is instantly
Left and right sled plate members 5 that move in a protruding manner and are attached to their lower ends
Grounds and leans in place of the flat tire 1.
Support a certain body. On the other hand, if the determination in S36 is NO
If so, all pneumatic tires 1 are punctured.
If not, return to S32 and repeat the above operation.
Run. The flat pneumatic tire 1 was replaced.
In this case, the operation is started by executing the initialization in S31.
It As described above, according to the fall prevention device of the present embodiment,
Initial stage when it is judged that the pneumatic tire 1 is flat
Then, the piston rod 4 suddenly moves and moves to the lower end.
The left and right sled plate members 5 attached are configured to be grounded.
Therefore, the car body will not be significantly inclined.
Reliably prevent the vehicle from falling or dropping the loaded load.
be able to. In addition, the fall prevention device of the present embodiment is
When sliding, the sled plate member 5 is grounded to support the vehicle body.
Because it is made, unevenness on the road surface such as unpaved road
Even if there is, the sled plate member 5 can be surely grounded.
And has excellent stability. In addition, in this embodiment, it is arranged on the left and right.
A pair of hydraulic cylinder 3 and piston rod 4
However, one hydraulic cylinder is installed in the center.
Connect the lower end of the piston rod to the central part of the connecting arm 6.
It can also be fixed to simplify the structure. In addition, this implementation
In the example, the piston rod 4 and the sled plate member 5 are
Uses pressure oil from the cargo handling hydraulic circuit as a drive source
Is ignited by a cylinder-shaped closed container filled with flammable gas.
A lag is provided and a flammable gas is generated by a control signal from the control unit 10.
The piston rod 4 and
Alternatively, the baffle plate member 5 may be configured to project.
Wear. (Embodiment 2) FIG. 4 is a schematic view of a fall prevention device according to this embodiment.
FIG. 5 is a schematic diagram showing the configuration of the control unit according to the present embodiment.
It is a block diagram. The fall prevention device of the present embodiment is
Basically the same as in Example 1, but supports provided on the left and right
Pneumatic tires 1a and 1b are panned because the legs operate independently.
If the vehicle is running at a high speed when
The point at which the support leg operates when
Roller members 13a and 13b instead of the sled plate member 5
They differ in the points used. Therefore this practice
In the example, the same reference numerals are used for the members and the like that are common to the first embodiment.
The detailed explanation is omitted and the explanation is centered on the above-mentioned different points.
Reveal As shown in FIG. 4, it was attached to the lower part of the vehicle body.
The pair of left and right hydraulic cylinders 3a, 3b are directed downward.
Each piston is equipped with a piston rod 4a, 4b that expands and contracts.
The ends of the rods 4a and 4b rotate in the vehicle width direction.
The roller members 13a and 13b rotatably held on the shaft are
Installed. Each hydraulic cylinder 3a, 3b is
Each is connected to the hydraulic pump 14 by an independent oil passage.
The control output from the control unit 20 to be described later is applied to both oil passages.
Signal to the hydraulic cylinders 3a, 3b
Solenoid-type first switching valve 15 that opens individually
It is arranged. Also, one pneumatic tire 1b has a vehicle
Is equipped with a speed sensor 16 that detects the running speed of
The speed sensor 16 outputs its detection signal to a control unit described later.
Output to 20. Then, the hydraulic power port in this embodiment is
The pump 14 is installed on the wheel portion of each pneumatic tire 1a, 1b.
Is a pressure oil supply source of the hydraulic brake device 17 placed,
A foot brake pedal (shown in the figure) is provided on the oil passage connecting the two.
Solenoid type second switching bar that opens and closes by
The lube 18 is provided. This second switching valve 18
Is connected to a control unit 20 which will be described later.
The brake can also be operated by the control signal output from
It has been burned. As shown in FIG.
Memory 20a containing gram, arithmetic means 20b, comparison
Means 20c, input / output interfaces 20d, 20e, etc.
It is composed of the main microcomputer. This
The control unit 20 includes a speed sensor 16 and a second switching valve.
18 is connected, which is different from the control unit 10 of the first embodiment.
It Then, the comparison means 20c inputs from the speed sensor 16.
The actual vehicle traveling speed S based on the detected signal
Low speed set speed S_OCompare and judge whether it is smaller than
Processing is also performed, and if it is determined to be small, the output interface
An operation signal is sent to the first switching valve 15 via the case 20e.
Output interface when output is judged to be large
Alarm device 9 and the second switching valve 18 via 20e.
Output a motion signal. Next, the operation of the fall prevention device of this embodiment will be described.
Follow the flow chart of the control unit 20 shown in FIG.
explain. First, in S31, initialization is performed by turning on the power.
Is executed, the next step S42 is playing from the pressure sensor 2.
Based on the detection signal input to the computing means 20b, t₁To
Pneumatic pressure P of each pneumatic tire 1a, 1b₁Is sought
It Then, in the next S43, the output from the calculation means 20b is performed.
Pneumatic pressure P₁Based on the calculation result of
Air pressure P₁Determines whether is less than the minimum air pressure Pmin
To do. If the determination here is YES, either
It is determined that a flat tire has occurred in the pneumatic tires 1a and 1b, and S
After jumping to 47 and activating the alarm device 9, after S48
Move to the operation below. On the other hand, the determination in S43 is NO.
If so, the process proceeds to the next S44, in which the pressure sensor 2 is changed to the calculation means 2
0b based on the detection signal input to 0b₂Each sky in
Air pressure P of pneumatic tires 1a, 1b₂Is required. Next S
In 45, the calculation means 20b (P₁-P₂) / (T₂−
t₁) Of each pneumatic tire 1a, 1b
The air pressure decrease rate (ΔP / Δt) is obtained. And next
At S46, the air pressure output from the calculating means 20b is reduced.
Based on the calculation result of the small rate (ΔP / Δt), the comparison means 2
0c is the air pressure decrease rate (ΔP / Δt) [ΔP / Δt]_O
Determine if greater than. If the determination here is NO
If so, puncture will occur in both pneumatic tires 1a and 1b.
If not, the process returns to S42 and repeats the above operation.
Return and execute. On the other hand, if the determination in S46 is YES
Has a flat tire on either the left or right pneumatic tire 1a, 1b.
If it is determined that the alarm has occurred, the process proceeds to S47 to activate the alarm device 9.
Let Then, in the next S48, the speed sensor 16 is turned on.
The comparison means 20c is based on the detected signal applied to the actual vehicle.
Both traveling speed S is set speed S_ODetermine if less than
It If the determination here is NO, the vehicle is at the set speed S._O
It is determined that the vehicle is traveling at a faster speed than
Then, the second switching valve 18 is operated. By this
From the hydraulic pump 14 to the hydraulic brake device 17
Is sent, the hydraulic brake device 17
It operates and the traveling speed of the vehicle decreases. And next S5
At 0, the comparison means 20c determines that the traveling speed S is the set speed S._OLess than
If yes or not, and if the determination here is NO, then YE
Until it is judged as S, that is, the traveling speed S is the set speed S_OYo
The determination in S50 is repeated until it becomes smaller. And
If the determinations in S50 and S48 are YES, the vehicle is
Set speed S_OTraveling at a slower speed than
It is judged that there is a flat air pressure in S51.
It is determined whether or not the ear is on the left side, and if YES, the process proceeds to S52.
Go forward and operate the first switching valve 15 so that the left side is open
Let As a result, the hydraulic pressure on the left side of the hydraulic pump 14 is
By sending pressure oil to the Linda 3a, the piston
The rod 4a was instantaneously projected and attached to the lower end of the rod 4a.
The roller member 13a on the left side is grounded to provide a flat air outlet.
Instead of the ear 1a, the body leaning to the left is supported.
If NO in S51, proceed to S53.
Operate the first switching valve 15 so that the right side is open.
It As a result, the hydraulic cylinder on the right side from the hydraulic pump 14
When the pressure oil is sent to the cylinder 3b, the piston lock
The right side attached to the lower end of the cable 4b
Pneumatic tire with flat roller member 13b
Instead of 1b, it supports the body leaning to the right. Na
Oh, when flat tires 1a, 1b are replaced
For the first time, the operation is started from the first S41. As above
In addition, according to the fall prevention device of the present embodiment, the pneumatic tire 1
At the initial stage when it is judged that a and 1b are flat,
The piston rods 4a, 4b momentarily project and move, and their lower ends
The roller members 13a and 13b attached to the
Because it is configured like this, the car body will tilt significantly
More reliably to prevent the vehicle from tipping over or the loaded load falling.
It can be prevented. In addition, the fall prevention of this embodiment
The device is designed such that the pneumatic tires 1a and 1b are flat when the vehicle is running.
However, when the vehicle's running speed drops enough, the piston
Rods 4a, 4b and roller members 13a, 13b project
As a grounding part that is configured to move and grounds to the road surface
Roller members 13a and 13b are used,
Piston rods 4a, 4b and rollers for supporting the body
To reduce the load on the members 13a and 13b.
It has excellent durability.

According to the fall prevention device of the present invention, when the pneumatic tire is punctured, the control section outputs a signal to the operating section so that the supporting leg instantly projects and the grounding section provided at the lower end thereof. It is configured to support the vehicle body at the initial stage that is inclining instead of the flat tire, grounding, so avoiding the occurrence of vehicle body inclination due to puncture,
It is possible to more reliably prevent the vehicle from falling and the load from falling. Further, if the grounding portion of the supporting leg is formed of the sled plate member, the sled plate member can be reliably grounded even when the road surface is uneven, and the stability is excellent. Further, if the grounding portion of the supporting leg is made of a roller member, the load of the load applied to the supporting leg when supporting the vehicle body can be reduced, and the durability is excellent.

[Brief description of drawings]

FIG. 1 is a configuration diagram schematically showing a fall prevention device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a control unit according to the first embodiment of the present invention.

FIG. 3 is a flowchart of a control unit of the fall prevention device according to the first exemplary embodiment of the present invention.

FIG. 4 is a configuration diagram schematically showing a fall prevention device according to a second embodiment of the present invention.

FIG. 5 is a block diagram of a control unit according to a second embodiment of the present invention.

FIG. 6 is a flowchart of a control unit of the fall prevention device according to the second embodiment of the present invention.

[Explanation of symbols]

1, 1a, 1b ... Pneumatic tire 2 ... Pressure sensor 3, 3a, 3b ... Hydraulic cylinder (operating part) 4, 4a, 4b ... Piston rod (supporting leg) 5 ... Sled plate member (grounding part) 6 ... Connecting arm (supporting leg) ) 7, 14 ... Hydraulic pump (operating part) 8 ... Switching valve (operating part) 10, 20 ... Control part 13a, 13b ... Roller member (grounding part) 15 ... First switching valve (operating part) 16 ... Speed sensor 17 … Hydraulic brake device 18… Second switching valve

Claims (2)

[Claims] 1. An industrial vehicle equipped with pneumatic tires, each of which is provided with a pressure sensor installed on each pneumatic tire for detecting an air pressure and a grounding portion at a lower end that slides on the ground so as to be movable below a vehicle body. Support leg, an operating part for operating the support leg, and a control part for projecting the support leg via the operating part when the air pressure of the pneumatic tire becomes a predetermined value or less based on a detection signal from the pressure sensor. An overturn prevention device for an industrial vehicle, comprising: 2. The overturn prevention device for an industrial vehicle according to claim 1, wherein the ground contact portion of the support leg is formed of a sled plate member or a roller member.