JP2848006B2 - Fork insertion control device of unmanned forklift - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fork insertion control device for an unmanned forklift.

[0002]

2. Description of the Related Art Conventionally, various methods of inserting a fork into a pallet in an unmanned forklift have been proposed. For example, JP-A-59-82299 discloses that
As shown in FIG. 9, an obstacle sensor 31 is provided at the tip of the fork 30, and the obstacle sensor 31
Of the pallet 3 is detected, that is, the insertion hole 33 is detected as not an obstacle.
2 facing the insertion hole. And the pallet 32
When the fork 30 is completely inserted as shown in FIG. 10 and the fork 30 is completely inserted as shown in FIG.
2 to lift the luggage.

[0003]

However, for example, when a wall 34 or the like is present behind the pallet 32 as shown by the dashed line in FIG. 11, the obstacle sensor 31 is located behind the wall while the fork 30 is being inserted. 34 is detected. When the obstacle sensor 31 detects the wall 34, a controller provided in the unmanned forklift judges this as an obstacle, stops the insertion operation, and there is a problem that the subsequent cargo handling operation cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to make it possible to normally insert a fork and to carry out loading and unloading operation even if there is something behind the pallet that does not hinder the insertion operation. It is to provide a fork insertion control device of an unmanned forklift capable of performing the following.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an obstacle sensor provided at the tip of a fork of an unmanned forklift for detecting an insertion hole of a predetermined pallet. A hole confirmation sensor provided at the rear of the fork and detecting whether the fork has been inserted into the insertion hole of the pallet; and a fork elevating means for matching the fork with the insertion hole of the predetermined pallet based on a detection signal of the obstacle sensor. When the obstacle sensor detects the insertion hole of a predetermined pallet, the insertion drive means for inserting a fork into the insertion hole, and when the hole confirmation sensor detects the inside of the insertion hole of the pallet,
The gist of the present invention is a fork insertion control device of an unmanned forklift provided with invalidation means for invalidating the obstacle sensor.

[0006]

When the insertion hole of the pallet is detected as a position where there is no obstacle by the obstacle sensor, the fork elevating means stops at that position and the fork is inserted into the insertion hole of the pallet by the insertion driving means. Wherein the fork insertion holes of the pallet is inserted is detected that is plugged into fork differentially included well by well check sensor simultaneously, the obstacle sensor is ineffective by the invalidation means. Therefore, even if an obstacle gate exists behind the pallet insertion hole, the obstacle sensor does not detect the obstacle.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a reach type unmanned forklift will be described below with reference to FIGS.
FIG. 2 is a schematic diagram showing an unmanned transport system. As shown in FIG. 2, an electromagnetic induction line L through which an induction signal flows is laid on a road surface between stations S in which luggage is stored. The traveling path of the forklift 1 is formed.
In front of each station S on the electromagnetic induction line L, a mark plate 2 for instructing the unmanned forklift 1 of operation information is arranged.

The mark plate 2 is capable of designating various operation information by arranging marks made of an iron plate or the like in various arrangement patterns, and the unmanned forklift 1 uses the known operation information of the mark plate 2 in a known manner. Read by method. In this embodiment, the operation information indicated by the mark plate 2 is operation information for executing the cargo handling operation after the unmanned forklift 1 is temporarily stopped.

FIG. 1 shows a side surface of an unmanned forklift 1. A pickup coil 3 for detecting the electromagnetic induction wire L is mounted on a lower surface of the forklift 1.
Similarly, a mark plate sensor 4 for detecting the mark plate 2 is mounted on the lower surface of the forklift 1. A pair of masts 5 (only one is shown) provided at a front portion of the forklift 1 are moved along a pair of leg portions 7 extending in the horizontal direction as the reach cylinder 6 expands and contracts.
It is designed to move back and forth. The amount of movement of the mast 5 before and after is defined by two limit switches M1 and M2 provided on the side of the reach cylinder 6.

The mast 5 is composed of an outer mast 5a and an inner mast 5b, and the inner mast 5b moves up and down as the lift cylinder 8 expands and contracts. A fork 10 is suspended and supported via a lift bracket 9 on a chain (not shown) mounted on a chain wheel (not shown) rotatably mounted on the inner side of the inner mast 5b. The lift bracket 9 is moved up and down by the chain wound or unwound with the elevation of the inner mast 5b, and the fork 1
0 goes up and down.

A rotary encoder 11 is connected to a chain wheel rotatably mounted on the inner side of the inner mast 5b. The rotary encoder 11 serves as a fork elevating means.
That is, a pulse corresponding to the amount of rotation of the chain wheel is generated to detect the lift position of the fork 10. Further, a tilt cylinder 12 for tilting the fork 10 is provided at a rear portion of the lift bracket 9.

In the body of the unmanned forklift 1, a hydraulic control circuit for driving and controlling the cylinders 6, 8, and 12 is provided, and an electromagnetic control valve V for projecting or contracting the cylinders 6, 8, and 12 is provided. A loading pump 13 for supplying hydraulic oil to each of the cylinders 6, 8, and 12 and a loading motor 14 for rotating the loading pump 13 are provided.

Further, in the body of the forklift 1, there are provided a steering motor 15 and a traveling motor 16 for steering and rotating the drive wheels D, as well as fork elevating means for controlling these, insertion driving means and invalidating means. A microcomputer C is provided, and the unmanned forklift 1 moves forward and backward by forward and reverse rotation of the driving wheel D and the driven wheel E which follows, and the fork 10 is inserted into the insertion hole P1 of the pallet P mounted at each station S. , And carry the package along with the pallet P.

As shown in FIGS.
At the front end of the pallet, an insertion hole P1 of the pallet P and an obstacle sensor 17 including a light emitting diode and a phototransistor for detecting an obstacle are mounted. Further, a hole confirmation sensor 18, which also includes a light emitting diode and a phototransistor, is mounted on the fork 10 behind (to the right in FIG. 2) the obstacle sensor 17. The obstacle sensor 17 is in the horizontal direction (left direction in the figure).
Hole detection sensor 18
Has a detection area on the lower side.

Next, the electrical configuration of the unmanned forklift 1 configured as described above will be described with reference to FIG. The microcomputer C includes a central processing unit (hereinafter referred to as a CPU) 19 and a ROM 20 in which a control program is stored in advance.
And a RAM 21 for temporarily storing the calculation results and the like of the CPU 19
The CPU 19 executes the traveling processing operation and the cargo handling operation of the unmanned forklift 1 in accordance with a control program stored in the ROM 20.

A steering motor 15 and a traveling motor 16 are connected to the CPU 19.
The pickup coil 3 is connected. The steering motor 15 is driven and controlled based on a detection signal from the pickup coil 3. Further, the mark plate sensor 4 is connected to the CPU 19, the mark plate sensor 4 detects the arrangement pattern of the mark plate 2, and outputs the detection signal to the CPU 19.
19 is output. The CPU 19 determines the operation information of the mark plate 2 based on the detection signal and controls the driving of the traveling motor 16, the steering motor 15 and the cargo handling motor 14.

Further, a rotary encoder 11 is connected to the CPU 19, and the rotary encoder 11 generates a pulse corresponding to the amount of winding or unwinding of the chain, that is, the amount of elevating the fork 10, and outputs the pulse to the CPU 19. CP
U19 inputs a pulse from the rotary encoder 11, and when the count value of the pulse reaches the reference lift pulse number stored in the ROM 20, the electromagnetic valve V for lift is closed to operate the lift cylinder. 8 is stopped.

When the obstacle sensor 17 detects the insertion hole P1 of the pallet P, the CPU 19 protrudes the reach cylinder 6 until the limit switch M1 is turned on, and moves the mast 5 forward. .
Next, the operation of the unmanned forklift having the above configuration will be described with reference to the flowchart of FIG.

First, the CPU 19 causes the unmanned forklift 1 to travel along the electromagnetic induction line L according to a control program stored in the ROM 20. And step 101
The CPU 19 determines whether or not the mark plate sensor 4 has detected the mark plate 2. When it is determined that the mark plate sensor 4 has detected the mark plate 2, the CPU 19 proceeds to step 102 and stops the unmanned forklift 1.

In the next step 103, the CPU 19
Drives the cargo handling motor 14 and opens the lift electromagnetic control valve V to cause the lift cylinder 8 to protrude. That is, the fork 10 is raised. Then, in step 104, the CPU 19
It is determined whether or not the count value of the pulse output from 1 has reached the reference lift pulse number. If the count value of the pulse from the rotary encoder 11 has reached the reference lift pulse number, it is determined in step 105 Stop climbing 10.

In the next step 106, the CPU 19
Determines whether the obstacle sensor 17 has detected the insertion hole P1 of the pallet P, and if the insertion hole P1 of the pallet P has not been detected, moves to the station 107.
Raise or lower the fork 10 and insert the hole P1 again.
Is detected. On the other hand, if the insertion hole P1 has been detected, the CPU 19 moves to the next step 108 to open the reach electromagnetic control valve V to cause the reach cylinder 6 to protrude. That is, the mast 5 is moved forward to insert the fork 10 into the insertion hole P1 (see FIG. 5).

Subsequently, at step 109, the CPU 1
9 turns off the obstacle sensor 17 at the same time as the lower surface of the pallet P is detected by the hole confirmation sensor 18. When the obstacle sensor 17 is turned off, even if a wall or an obstacle 22 exists behind the pallet P, the obstacle sensor 17 does not output a signal to that effect to the CPU 19 (see FIG. 6).

Then, in steps 110 and 111, the CPU 19 continues to make the reach cylinder 6 protrude until the limit switch M1 is turned on.
Into the insertion hole of the pallet P (see FIG. 7).
In the last step 112, the CPU 19 raises the pallet P by projecting the lift cylinder 8 to raise the fork 10, and transports the pallet P to a predetermined station S.

As described in detail above, according to the unmanned forklift 1 of this embodiment, when the fork 10 is inserted into the insertion hole P1 of the pallet P, the obstacle sensor 17 is turned off. Even if a wall, luggage, or the like is present, the wall, luggage, or the like is not detected while the fork 10 is being inserted. Therefore, cargo handling, walls, and the like can be arranged behind the pallet P. That is, the space in the factory can be used effectively, and the unmanned transport system can be expanded.

It should be noted that the present invention is not limited to the above-described embodiment, and may be configured as follows, for example, without departing from the spirit of the invention. (1) In the above embodiment, the bottom surface of the pallet P was detected by the hole confirmation sensor 18,
May be configured to detect a partition plate provided at the upper surface of the pallet or at the center of the pallet P.

(2) In the above embodiment, the obstacle sensor 17
Is turned off at the same time as the hole confirmation sensor 18 detects the lower surface of the pallet P, but this is attached to the center portion of the lift bracket 9 so that the distance from the pallet P becomes a predetermined distance by the distance sensor. In such a case, the obstacle sensor 17 may be turned off. (3) In the above embodiment, the obstacle sensor 17 is formed of a phototransistor and a light emitting diode, but may be constituted by an ultrasonic sensor, an infrared sensor, or the like.

(4) In the above embodiment, the hole confirmation sensor 18
Is formed of a phototransistor and a light emitting diode, which are mounted on the left and right sides of the fork 10 by attaching transmissive sensors (light emitter and light receiver), and emitted from the light emitter by a partition plate provided at the center of the pallet P. The obstacle sensor 17 may be configured to be turned off when the blocked light is blocked.

[0028]

As described in detail above, according to the present invention, even if there is something that does not hinder the insertion operation behind the pallet, the fork can be normally inserted and the cargo handling operation can be performed. It has excellent effects.

[Brief description of the drawings]

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

FIG. 2 is a plan view schematically showing an unmanned transfer system.

FIG. 3 is a block diagram showing an electric configuration of the unmanned forklift.

FIG. 4 is an enlarged side view showing an obstacle sensor and a hole confirmation sensor mounted on a fork tip.

FIG. 5 is a partial side sectional view showing a section of each sensor of the fork and an insertion hole of the pallet.

FIG. 6 is a partial side sectional view showing a state where a fork is inserted into an insertion hole of a pallet.

FIG. 7 is a partial side sectional view showing a state where the fork is completely inserted into the insertion hole of the pallet.

FIG. 8 is a flowchart showing the operation of the CPU.

FIG. 9 is a partial side sectional view showing a fork tip and a pallet of a conventional unmanned forklift.

FIG. 10 is a partial cross-sectional view showing a state of a pallet lifted by a fork of a conventional unmanned forklift.

FIG. 11 is a partial side sectional view showing a state in which a fork of a conventional unmanned forklift is inserted into an insertion hole of a pallet, and a wall is detected by an obstacle sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Unmanned forklift, 6 ... Reach cylinder as insertion drive means, 10 ... Fork, 11 ... Rotary encoder as fork raising / lowering means, 17 ... Obstacle sensor,
18: hole confirmation sensor, C: microcomputer as fork lifting / lowering means, insertion driving means, and invalidating means, P
... pallet, P1 ... insertion hole.

Claims (1)

(57) [Claims] An obstacle sensor is provided at the tip of a fork of an unmanned forklift and detects an insertion hole of a predetermined pallet. The obstacle sensor is provided at a rear portion of the fork with respect to the obstacle sensor and whether a fork is inserted into the insertion hole of the pallet. A hole confirmation sensor to be detected, a fork elevating means for matching a fork with a predetermined pallet insertion hole based on a detection signal of the obstacle sensor, and when a predetermined pallet insertion hole is detected by the obstacle sensor. An insertion drive means for inserting a fork into the insertion hole, and when the hole confirmation sensor detects the inside of the insertion hole of the pallet,
A fork insertion control device for an unmanned forklift, comprising a disabling means for disabling the obstacle sensor.