JPH10279297A - Automatic forklift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a load weight from exceeding a permissible capacity by attaching a front article identifying sensor to the rear upper position of a fork so as to check the unscheduled loading of an article on an article to be loaded. SOLUTION: An automatic forklift is composed of a chassis 1, a machine body frame 3 and a carriage 4, and a fork 6 is attached so as to be freely moved up and down. In this case, first to third sensors 1a, 4a and 6a are attached to the tips of the chassis 1, the carriage 4 and the fork 6, and a fourth sensor 8a is attached to the upper end of a backrest 8 moved up and down integrally with a fork 4 extended to the rear end of the fork 6. For loading, the placing of a load in a specified position is first identified by the third sensor 6a and, simultaneously, the placing of another load on the load is identified by the fourth sensor 8a. If the overlapped load is identified, and if it is a load unscheduled for loading, work is immediately interrupted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unmanned forklift for performing a cargo handling operation in accordance with preprogrammed data.

[0002]

2. Description of the Related Art In factories and warehouses where a luggage storage location is determined, the contents of cargo handling are programmed in advance based on the condition of the cargo to be unloaded, and unmanned operations are performed by operating a forklift according to the program. Is being promoted. In that case, make sure that the forklift does not slip between the luggage and the fork when loading.
At the time of loading and unloading, a function to check whether a loading space is secured or the like and a function to confirm whether there is an obstacle or a person in front during traveling are necessary. Therefore, in a conventional unmanned forklift, for example,
As described in Japanese Patent Publication No. 31161, a sensor is provided at the tip of a fork to enable the presence or absence and position of a baggage to be checked at a designated position, and an emergency stop mechanism is provided as an interpersonal means. Have been.

[0003]

SUMMARY OF THE INVENTION In a warehouse in which a plurality of shelves partitioned vertically and horizontally are provided and a storage location is set for each package, if the designated storage location is vacant, the situation above it Regardless of what you are doing, you can freely unload and unload, but at the stacking place where you stack and store in order from the back, when loading the designated frontmost luggage, the luggage stacked on the target luggage will If the number of stages exceeds the planned number, it is expected that the allowable load will be exceeded. To prevent this, you can move the fork up and down before loading, check the stacking height using a sensor attached to the tip of the fork, for example, and check if the condition of the load is according to the program. In addition to the inefficiency, power is consumed by raising and lowering the fork, leading to a reduction in operating time. Also, there is no way to confirm the situation above the top dead center of the fork.

[0004]

SUMMARY OF THE INVENTION The present invention relates to an unmanned forklift capable of confirming a loaded state, wherein the unmanned forklift is provided with a front object confirmation sensor at a position above a rear portion of a fork. is there. The sensors can be provided so as to be able to move up and down, can be provided in a plurality in the up and down direction with an interval therebetween, or can be attached to the upper end of a backrest that moves up and down integrally with a fork. When the sensor confirms the presence of a load at a predetermined height position in front, a control device having a function of determining whether or not to execute a work program is mounted, or a tip of a fork and a tip of a lower frame are mounted. It is also possible to provide a sensor for confirming an object in front of at least one of them.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An unmanned forklift according to the present invention (hereinafter simply referred to as a forklift) will be described with reference to the drawings. FIG. 1 shows a side view of a forklift. A chassis 1 is provided with wheels 2, 2 ',... At the front, rear, left and right, and the rear wheel 2' (2 ') is used as a driving wheel. An airframe 3 is attached to the rear half of the chassis 1, and the leg 1 'of the front half is
A carriage 4 is movably mounted in the front-rear direction, and a pair of left and right masts 5 are vertically provided at the rear end of the carriage 4. A fork 6 is attached to the mast 5 so as to be able to move up and down along the mast 5.
By operating the fork 6 and a hydraulic cylinder (not shown), a cargo handling operation is possible. In the machine main body 1, a driving motor connected to the wheels 2, a hydraulic unit for supplying hydraulic pressure to a hydraulic cylinder, and a drive source such as a battery for driving the driving motor and the hydraulic unit (any of which). Are also not shown), and a control device 7 for controlling the driving source.

The control device 7 has an automatic control function of traveling and cargo handling operation according to a program, and executes a traveling mode and a cargo handling mode in accordance with a command of a control mechanism by storing the program in advance. Forklifts are operated unmanned.

[0007] A first sensor 1a, a second sensor 4a, and a third sensor 6a are mounted on the respective ends of the chassis 1, the carriage 4 and the fork 6, respectively.
From the rear end of the fork 6, a backrest 8 that moves up and down integrally with the fork 4 extends upward, and a fourth sensor 8a is attached to the upper end of the backrest 8.

[0008] Among the sensors 1a, 4a, 6a, 8a, the first sensor 1a attached to the tip of the chassis 1 is of a contact type, but the other second to fourth sensors 4a
Non-contact type using light or ultrasonic wave is adopted for all of a, 6a and 8a. First to fourth sensors 1a,
The signals 4a, 6a, and 8a are all input to the control device 7, and the control device that has received the signals from the sensors performs a predetermined operation in accordance with each program of the traveling mode and the cargo handling mode.

Next, a control example will be described. In driving mode,
The vehicle travels along a traveling line provided on the floor while checking the front by the second sensor 4a. The second sensor 4a is a long-distance type having a detection area of 1 meter or more, and outputs a detection signal when an obstacle X such as a human is confirmed on the traveling route as illustrated in FIG.
When the detection signal is input to the control device, the control device outputs an emergency stop command. Therefore, the vehicle is stopped for a predetermined time, and if a person crosses temporarily, the situation is resolved within the predetermined time and the travel is resumed. However, if it is not resolved within 5 seconds, for example, it is determined that the person is not a human, and an alarm is issued. As a result, the user is prompted to move to a truck standing on the traveling route, or to remove any misplaced luggage. When approaching the predetermined stop position, the second sensor 4a is disabled so that the emergency stop does not occur due to the confirmation of the cargo to be unloaded.

When the second sensor is disabled, the first, third, and fourth sensors 1a, 6a, 8a are enabled, and the vehicle is advanced at a very low speed to continue checking the position of the load. The other sensors 1a, 6a and 8a other than the second sensor 4a can be enabled during the running mode. Slow forward,
If there is an unscheduled baggage M such as a left baggage before the predetermined position, the baggage M is detected by the third sensor 6a, and the forklift stops in front of the left baggage. in this case,
When the cargo handling object is stacked on the existing luggage or is stacked on the upper stage of the existing luggage M ′, as shown in FIG.
Although the baggage M in front cannot be detected by the third sensor 6a, in that case, it is detected by the first sensor 1a. If there is nothing before the predetermined position, the robot advances to the predetermined position.

When the vehicle arrives at the predetermined position, the mode shifts to the cargo handling mode. When unloading, if the unloading place is vacant, the unloading is completed and the vehicle goes to the next designated place. As illustrated in FIG. 4, when another package M is placed at the unloading scheduled place, the package M is detected by the third sensor 6a, and the operation is temporarily stopped. If another baggage is placed at the place where the cargo is to be unloaded as described above, the program will be canceled if it is programmed to unload the already placed baggage or if another unloading place is designated. Work can be performed without any

In the case of loading, it is first checked by a third sensor 6a whether a package is present at a predetermined place, and at the same time, it is checked by a fourth sensor 8a whether another package is loaded on the package. I do. If there is no stacked luggage, the vehicle advances at a very low speed as it is, stops when the first sensor 1a comes into contact with the luggage, and uses the third sensor 6a to place the fork 6 on the pallet of the luggage M to be loaded. After the fork 6 is moved forward and lifted to receive the load M (FIG. 5A), the load is completed (FIG. 5B). Go to the expected location.
As shown in FIG. 6, when the fourth sensor 8a confirms the stacked luggage, the program first checks whether or not the luggage is scheduled, and if it is specified that the luggage is to be loaded while a plurality of luggage are stacked. The same operation as above is continued while being stacked, and is interrupted immediately if it is not scheduled.

[0013] Both loading and unloading depend on the program, but it is checked whether there is multi-stacking, and if multi-stacking is performed, it is not stopped even if it is unscheduled. If you set abundant options such as loading or canceling the row and moving to the next row, the work will not be interrupted at that point, and even if you execute the work, the unexpected load Over can be avoided.

In the forklift of the embodiment, since the fourth sensor 8a is attached to the upper end of the tall backrest 8, all the individual loads are unified to the ideal height slightly lower than the height of the backrest. If present, the fourth sensor 8
The position of a is synchronized with the stacking pitch and the baggage stacked above is reliably detected, but there is no guarantee that all the cargo to be handled is at the same height, so even if the baggage is stacked If the height is lower than the fourth sensor position, or if the stacking height is higher than expected, it will not be detected even if the fork is moved up and down. As shown in FIG. 7, a plurality of fourth sensors 8a, 8a,... Are provided at intervals above and below, and selectively used depending on the situation, or as shown in FIG. Attaching the fourth sensor 8a to the tip of the telescopic pole 9 provided on the mast 5, the attachment position, the number, and the like can be changed as appropriate.

Further, the detection area of the sensor is not limited to the front, and the fourth sensor 8a is effective for obliquely upward and downward as shown in FIG. 9 to determine how many stages of the load M are stacked. If the count can be performed or the detection distance is made variable, it is possible to execute a more complicated program. In addition, when unloading, it is possible to accumulate the order from the bottom, when it reaches the scheduled height, detect it 8a with the fourth sensor, and stack it in the next row from the next, in that case,
As illustrated in FIG. 10, stoppers 10, 10 projecting upward from the floor surface are provided at positions immediately before the stacking position.
Is provided, the stop position can be confirmed by the first sensor 1a using the stoppers 10, 10,..., And accurate positioning can be performed without the assistance of a control device. And if there is unscheduled luggage at the location of the cargo or another luggage is loaded on the luggage,
By confirming these and adding a function of determining whether or not to execute the subsequent work with the control device, even if the vehicle is completely unmanned, such as at night, the vehicle will not stop and wake up in the morning. Note that the forklift of the present invention checks the status of the load to be loaded and prevents the load from exceeding the allowable load. Rather, for example, switching the first sensor between short-distance and long-distance, and omitting the second sensor, while running, lowering the fork and detecting the front only with the third sensor, etc. The program contents of the running mode and the cargo handling mode based on the detection signals from the sensors and the mounting position, the contact type or the non-contact type, and the program contents may be changed as appropriate.

[0016]

According to the present invention, it is checked whether unplanned luggage is loaded on the luggage to be loaded, so that the loaded weight does not exceed the allowable amount and the reliability is improved. Is high. Further, by making the sensors movable up and down or by providing a plurality of sensors, it is possible to eliminate the case where the stacking height changes depending on the size of the load or the sensor is too high to detect. If the sensor is provided at the upper end of the backrest, the sensor moves up and down together with the fork and operates efficiently. Further, after confirming unscheduled luggage, it is possible to cope with any situation by providing a function of determining the continuation of the work or adding another sensor.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of an unmanned forklift according to the present invention.

FIG. 2 is an explanatory diagram when an obstacle is present on a traveling route.

FIG. 3 is an explanatory diagram in a case where a forgotten baggage is present in front of a predetermined position.

FIG. 4 is an explanatory diagram in the case where another package is placed at the unloading scheduled place.

FIGS. 5A and 5B are explanatory diagrams of a loading operation.

FIG. 6 is an explanatory diagram in the case where stacked luggage is confirmed.

FIG. 7 is an explanatory diagram of a modified example.

FIG. 8 is an explanatory diagram of a modified example.

FIG. 9 is an explanatory diagram of a modified example.

FIG. 10 is an explanatory diagram of an example in which a stopper is provided at a loading / unloading position.

[Explanation of symbols]

1. Chassis, 1 'leg part, 1a first sensor, 2, 2' wheel, 3 ... body frame, 4 ...
Carriage, 4a, second sensor, 5, mast, 6
..Fork, 6a..third sensor, 7..control device, 8.backrest, 8a..fourth sensor, 9.
-Pole, 10-Stopper, X-Obstacle, M, M '
··Baggage.

Claims (6)

[Claims] 1. An unmanned forklift having a front object confirmation sensor attached to a position above a rear portion of a fork. 2. The unmanned forklift according to claim 1, wherein the sensor is provided so as to be movable up and down. 3. The unmanned forklift according to claim 1, wherein a plurality of the sensors are provided in a vertical direction with an interval therebetween. 4. The unmanned forklift according to claim 1, wherein the sensor is attached to an upper end of a backrest that moves up and down integrally with the fork. 5. A control device having a function of determining whether or not to execute a work program when the sensor confirms the presence of a load at a predetermined height position in front of the control device. An unmanned forklift according to any one of the above. 6. The unmanned forklift according to claim 1, wherein a front object confirmation sensor is provided on at least one of the tip of the fork and the tip of the lower frame.