JP2001278598A - Forklift traveling system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forklift traveling system capable of securing the sufficient safety without increasing a cost. SOLUTION: A projector 11 is provided in a warehouse building 2 so as to show a boundary of the predetermined zone with the light projected by the projector 11. A forklift 1 is provided with a light receiver 12 for receiving the light projected from the projector 11. The forklift 1 detects the approach thereof into the predetermined zone with the light receiver 12, and limits the maximum speed in this predetermined zone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a forklift traveling system.

[0002]

2. Description of the Related Art A forklift is provided with an accelerator pedal. The running speed of the forklift changes according to the depression angle of the pedal. FIG. 3 is a graph showing the relationship between the accelerator pedal depression angle and the traveling speed for the forklift in the forklift traveling system of the present invention.
The straight line D in this graph is the same as the relationship between the pedal depression angle and the traveling speed in the conventional forklift. That is, in the conventional forklift, the traveling speed increases almost in proportion to the depression angle of the accelerator pedal, and the maximum speed M can be obtained at the maximum depression angle F. Therefore, the driver has performed various forklift operations while adjusting the traveling speed by adjusting the depression angle of the accelerator pedal according to the surrounding conditions and the like. For example, when traveling on a wide outdoor road, while driving a forklift at high speed to reduce work time, the traveling area is in a warehouse building, a place where many people are working, luggage is piled up on both sides. For example, when the vehicle is in a place, a relatively narrow passageway, an elevator, or the like, the forklift is operated with the traveling speed suppressed to a predetermined speed or less for safety.

[0003]

However, if the driver's eyes are accustomed to high-speed running, for example, there may be cases where sufficient deceleration cannot be achieved by adjusting the accelerator pedal based on the bodily sensation. If the traveling speed is kept high by a little carelessness, a serious accident may be caused, so that there is a problem that a large cost is required for operation management at the work site. In addition, there is a variation in the safety that can be ensured between a skilled driver and a non-skilled driver, so that operation management must be performed on the basis of an unskilled driver, and there is a problem that the above-mentioned costs are wasteful.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a forklift traveling system capable of ensuring sufficient safety without incurring great cost. To provide.

[0005]

Means and Effects for Solving the Problems Claim 1
A forklift traveling system that transmits a signal indicating a boundary of a predetermined zone defined in a traveling area of the forklift, receives the signal transmitted from the transmitter, and performs the predetermined zone based on the received signal. And a forklift configured to detect a rush into the vehicle and limit the maximum vehicle speed to be lower than usual when the vehicle is within the predetermined zone. Here "normal time"
Means that the forklift is outside the predetermined zone.

[0006] In this forklift traveling system, the boundary of a predetermined zone is formed by the transmitter, and the maximum vehicle speed of the forklift is restricted in this zone more than outside the zone. Therefore, the vehicle speed can be forcibly limited in an area where a forklift travels at a high speed, such as in a warehouse building, where there is a danger. For this reason, sufficient safety can be ensured without incurring a large cost for operation management of the forklift.

A forklift traveling system according to a second aspect of the present invention includes a sensor for detecting that the forklift has approached the predetermined zone. When the sensor detects that the forklift has approached the predetermined zone, the forklift travels. Is activated.

In this forklift traveling system, it is detected that the forklift has approached the predetermined zone, and the transmitter is operated only when necessary. Accordingly, it is possible to reduce the cost due to the operation of the transmitter, and it is possible to extend the service life of the transmitter by avoiding continuous operation.

[0009]

Next, a specific embodiment of a forklift traveling system according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing the forklift traveling system. Forklift 1 is a warehouse building 2
It can carry luggage in and out of the vehicle, and the traveling speed can be adjusted by the depression angle of an accelerator pedal (not shown). The warehouse building 2 includes an entrance 3 through which the forklift 1 enters and exits. A light projector 11 is provided on the upper side 5 of the entrance 3 so as to project light downward. FIG. 2 is a schematic plan view showing the vicinity of the entrance 3 of the warehouse building 2. As shown in the figure, the light projector 11 projects light outside the vicinity of the entrance 3, and forms a light projecting area 4 from the entrance 3 to the outside. On the other hand, a light receiver 12 that receives light emitted from the light projector 11 is mounted on an upper surface of a head guard 10 provided in the forklift 1. The forklift 1 is provided with a control device (not shown), which limits the vehicle speed, which will be described later, according to whether or not the light receiver 12 has received light from the light emitter 11. A tape switch 14 is provided on the track 20 on which the forklift 1 runs so as to surround the light projecting area 4 from outside. This tape switch 14
Is for detecting passage of the forklift 1. In response to the pressing of the tape switch 14, the light emitting device 11 can be turned on and off by a controller (not shown) on the warehouse building 2 side.

Next, the operation of the forklift traveling system configured as described above will be described. First,
When the forklift 1 is located outside the tape switch 14 and is separated from the entrance 3 of the warehouse building 2, the light emitter 11 is turned off. Therefore, the light receiver 12 provided in the forklift 1 does not receive the light from the light emitter 11, and the control device does not limit the vehicle speed of the forklift 1. The relationship between the depression angle of the accelerator pedal and the vehicle speed at this time is indicated by a straight line D in FIG. That is, until the vehicle speed reaches the limit speed M at the maximum depression angle F, the vehicle speed increases substantially in proportion to the depression angle of the accelerator, and this is the normal vehicle speed of the forklift 1.

When the forklift 1 further advances from this state and the tape switch 14 is pressed by the front wheel of the forklift 1, the controller turns on the light emitter 11. The rear wheel of the forklift 1 immediately passes over the tape switch 14, but a predetermined time window is provided in the controller.
The pressing of the tape switch 14 due to the passage of the rear wheel is ignored. When the floodlight 11 is turned on, the floodlight area 4 is formed from the entrance 3 to the outside as described above. When the forklift 1 further advances and enters the light emitting area 4, the light receiver 12 receives light from the light emitter 11. Then, the control device of the forklift 1 limits the vehicle speed of the forklift 1. The relationship between the depression angle of the accelerator pedal and the vehicle speed at this time is indicated by a polygonal line A in FIG. That is, the vehicle speed rises in almost the same manner as in the normal case until the vehicle speed reaches the limit speed N at the threshold depression angle T, and the vehicle speed is limited even if the accelerator is depressed from here to the maximum depression angle F. That is, it does not rise above the speed N. The speed limit N is a value smaller than the speed limit M.

Even if the forklift 1 enters the warehouse building 2 from the entrance 3, the vehicle speed of the forklift 1 is controlled according to the polygonal line A. Therefore, the maximum vehicle speed of the forklift 1 is limited to the speed limit N in a zone formed by the light projecting area 4 and the warehouse building 2. Therefore, the light projecting area 4 indicates the boundary of such a zone, the light projector 11 functions as a transmitter for transmitting a signal indicating the boundary, and the light receiver 12 functions as a receiver for receiving the signal. The tape switch 14 functions as a sensor for detecting that the forklift 1 has approached the zone.

When the forklift 1 leaves the warehouse building 2 through the entrance 3, the light emitter 11 remains lit, so that the light receiver 11 receives the light from the light emitter 11 again. Then, the control device of the forklift 1 operates to release the vehicle speed limitation. That is, the relationship between the depression angle of the accelerator pedal and the vehicle speed returns to that shown by the straight line D in FIG. When the forklift 1 further travels and leaves the warehouse building 2, the tape switch 14 is pressed by the front wheel. Then, the controller on the warehouse building 2 side is operated by this pressing, and the floodlight 1
1 is turned off. Also in this case, the rear wheel of the forklift 1 immediately passes over the tape switch 14, but since the controller has a predetermined time window, the pressing of the tape switch 14 again by the passage of the rear wheel is ignored. It has become.

In the above-described forklift traveling system, the boundary of a predetermined zone defined in the traveling area of the forklift 1 is formed by the light emitter 11, and the maximum vehicle speed of the forklift 1 is limited in this zone. Accordingly, the maximum vehicle speed is forcibly limited in an area where the forklift 1 travels at high speed, such as in the warehouse building 2, which may be dangerous. Therefore, the safety can be ensured at the work site without incurring a large cost for operation management. In addition, since the maximum vehicle speed of the forklift 1 itself is limited, there is no variation in the safety secured between the skilled driver and those who are not.

In the above, the tape switch 14 detects that the forklift 1 has approached the zone, and turns on the projector 11 only when necessary.
That is, here, the tape switch 14 functions as a sensor that detects that the forklift 1 has approached the zone. Therefore, the cost due to the operation of the light projector 11 can be reduced, and heat generation due to continuous operation can be avoided to extend the service life of the light projector 11.

Further, in the above description, as shown by the polygonal line A in FIG. 3, the vehicle speed is increased in the same manner as in the normal state until the vehicle speed reaches the limit speed N at the threshold depression angle T.
Therefore, a normal feeling of increasing the vehicle speed is obtained up to the threshold depression angle T, and it is possible to suppress a sense of discomfort given to the driver when the vehicle speed is limited.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be implemented with various modifications within the scope of the present invention. In the above, runway 2 of forklift 1
0, a tape switch 14 is provided, and the tape switch 14 functions as a sensor for detecting that the forklift 1 has approached the zone. As shown in FIG. 1, a proximity sensor 15 using ultrasonic waves or the like may be provided in the warehouse building 2 or the like, and the proximity sensor 15 may detect the proximity of the forklift 1 to the zone.

In the above description, the vehicle speed is increased at the threshold depression angle T until the vehicle speed reaches the limit speed N in the same manner as in a normal case, thereby suppressing the sense of discomfort given to the driver when the vehicle speed is limited. However, if the driver does not care about the sense of discomfort, as indicated by the straight line B in FIG.
The vehicle speed may be increased substantially in proportion to the stepping angle so that the vehicle speed reaches the limit speed N at the maximum stepping angle F. In this case, since the vehicle speed is always limited, further safety is ensured. Further, as indicated by a curve C in the figure, the vehicle speed may be smoothly limited as the vehicle approaches the maximum depression angle F. In this case, since the vehicle speed restriction characteristic is intermediate between the broken line A and the straight line B, necessary safety can be secured without giving the driver a great feeling of strangeness. In addition to these,
Needless to say, the maximum vehicle speed of the forklift 1 can be limited by giving various correlations between the accelerator pedal and the vehicle speed.

Further, in the above description, the light projected by the light projector 11 indicates the boundary of the zone for limiting the vehicle speed.
For example, the boundary may be indicated by using a transmitter that emits a signal such as a radio wave or an ultrasonic wave. In this case, a receiver for receiving signals such as radio waves and ultrasonic waves is provided in the forklift 1 instead of the light receiver 12. Further, a reflection type sensor having a light emitting unit and a light receiving unit may be provided on the forklift 1 and a light reflecting tape may be provided on the track 20 so as to indicate the boundary of the zone.
In such a forklift traveling system, the light emitted from the light emitting unit and reflected by the light reflecting tape is received by the light receiving unit, and the maximum vehicle speed is limited based on the light. Therefore, in this case, the light reflecting tape functions as a transmitter for transmitting a signal indicating the boundary of the predetermined zone.

In the above, an example has been described in which the interior of the warehouse building 2 is set as a zone for limiting the vehicle speed. However, a specific room or elevator in the warehouse building 2 may be set as the zone. Also, since the boundary of the zone can be determined by a signal emitted from a transmitter such as the light projector 11,
Not only the part physically partitioned such as inside the building is used as the vehicle speed limiting zone, but also a part of the wide traveling area of the forklift 1 where a large number of workers are present, in particular, the vehicle speed limiting zone by the signal. Can also be set as

Further, in the above, the ON / OFF of the vehicle speed limit is toggled by receiving the light from the projector 11, but depending on the setting of the zone and the type of the transmitter, when the signal is not received from the transmitter. The normal vehicle speed control may be performed, and the above-described vehicle speed restriction may be performed when a signal is received. Further, in the embodiment of FIG. 1 described above, the zone is set within a range where the light projected by the light projector 11 reaches. However, when the forklift first crosses the tape switch 14 or the like, it is considered that the forklift has entered the zone, and the crossing is performed again. It is also possible to set so that it is determined that the vehicle has escaped from the zone when the vehicle has come out.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a forklift traveling system according to an embodiment of the present invention.

FIG. 2 is a schematic plan view showing the forklift traveling system.

FIG. 3 is a graph for explaining a vehicle speed limitation of a forklift constituting the system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Forklift 4 Floodlight area 11 Floodlight 12 Detector 14 Tape switch

Claims (2)

[Claims] A transmitter for transmitting a signal indicating a boundary of a predetermined zone defined in a traveling area of a forklift;
A forklift that receives the signal transmitted from the transmitter, detects a rush into the predetermined zone based on the received signal, and limits the maximum vehicle speed to be lower than normal when in the predetermined zone. A forklift traveling system comprising: 2. A system according to claim 1, further comprising a sensor for detecting that the forklift has approached the predetermined zone, and activating the transmitter when detecting that the forklift has approached the predetermined zone. The forklift traveling system according to claim 1, wherein: