JP2000086198A - Reach type unmanned forklift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reach type unmanned forklift capable of placing a load on a rack without making the rack instable. SOLUTION: A fork 15 is provided with a center detection means for detecting the longitudinal center position of a cargo. The center detection means includes a first sensor 25 for detecting whether or not the rear end of the cargo is located at the root of the fork and a plurality of second sensors 28 for detecting the position of the front end of the cargo. A forklift 11 has a control device 30 for controlling the amount of reach of the fork achieved by a reach part 13, so that during storage of the cargo on a rack, the center position of the cargo is located at the center of the storage surface of the rack.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reach type unmanned forklift.

[0002]

2. Description of the Related Art FIG. 7 shows a side view of a conventional reach type unmanned forklift used in an unmanned warehouse. A functional product room 2 for storing functional products for controlling the operation of the forklift vehicle is provided at the rear of the forklift 1, and a pair of left and right forks 3 is provided at the front of the vehicle. The pair of forks 3 is supported by a pair of left and right masts 4 so as to be able to move up and down. These pair of masts 4
Are supported so as to be slidable in the vehicle front-rear direction, that is, reachable along reach rails formed on a pair of left and right reach legs 5 extending forward from the front wall of the functional product room 2.

In such a reach type unmanned forklift, a vehicle is driven to a position near a load, and a pair of left and right masts 4 are advanced along a reach rail in a reach leg 5 so that a pair of left and right forks together with the mast 4 is provided. The fork 3 was also moved forward just below the load, and the load was placed on the fork.

[0004]

However, the reach type unmanned forklift 1 has no means for recognizing the size of the load placed on the fork 3, so that when the load is placed on the shelf, the load ends. I had no choice but to put the part on the front edge of the shelf. For this reason, the center of the shelf may be displaced from the center of the load, and a moment may be generated by the weight of the load, and the shelf may be unstable.

Accordingly, it is an object of the present invention to provide a reach type unmanned forklift capable of placing a load on a shelf without making the shelf unstable.

[0006]

In order to achieve the above-mentioned object, a reach type unmanned forklift of the present invention is provided with a fork provided to be able to move up and down along a mast, and the mast is moved in the longitudinal direction of a vehicle. A reach portion, center detecting means provided on the fork for detecting the center position of the load on the fork in the front-rear direction, and the center position of the load obtained from the center detecting means when the load is stored on the shelf is stored on the shelf And a control device for controlling an amount of reach of the fork by the reach portion so as to be located at the center of the surface.

The center detecting means includes a first sensor provided at the base of the fork for detecting whether the rear end of the load is located at the base of the fork, and detecting the position of the front end of the load. A plurality of second sensors arranged along a fork may be provided as needed. The first sensor may comprise a lever switch with a lever that is actuated by the load when the load is placed on the base of the fork.

[0008] Each of the second sensors may be constituted by a limit switch provided with an operating piece which is protruded from the upper surface of the fork and is pushed by the bottom surface of the load, or may be constituted by a photoelectric switch. .

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Embodiment 1 FIG. FIG. 1 shows a reach type unmanned forklift according to Embodiment 1 of the present invention. The reach type unmanned forklift 11 can store a load on a shelf or take out a load from a shelf in an unmanned warehouse. At the rear of the forklift vehicle, there is provided a functional product room 12 for storing functional products for controlling various operations of the forklift. On the other hand, at the front of the forklift vehicle,
A reach 13, a pair of left and right masts 14 and a fork 15 are provided, respectively.

The reach portion 13 includes a pair of left and right reach legs 16 each having a rear end 17 connected to the front wall of the functional product room 12 and extending in the vehicle longitudinal direction, a mast 14 and a fork 1.
5 is provided with a hydraulic cylinder (not shown) for reaching the reach 5 along the reach leg 16. A front wheel 19 is attached to a front end 18 of each reach leg 16. The reach legs 16 are spaced apart from each other in the vehicle width direction and arranged in parallel. A reach rail is formed on the inner surface of each reach leg 16 along its longitudinal direction. The lower ends of the corresponding masts 14 are respectively attached to the pair of left and right reach rails, and the pair of masts 14 are slidably moved in the vehicle front-rear direction by the pair of reach rails, that is, guided and supported so as to be reachable. You.

A lift bracket 20 is attached to the pair of left and right masts 14 so as to be able to move up and down, and a pair of left and right forks 15 is attached to the lift bracket 20. That is, the pair of left and right forks 15 move up and down along the pair of masts 14 together with the lift bracket 20. In addition, the lift bracket 20 includes
A backrest 21 for preventing a load placed on the fork 15 from being displaced toward the functional product room 12 is attached.

The left and right forks 15 are provided with center detecting means for detecting the center of the load in the front-rear direction in order to recognize the size of the load mounted. That is, as shown in FIG.
The second sensor 2 is provided with a first sensor 25 that can detect whether the rear end 24 of the load is positioned at the root 22 of the fork 15 when the load 23 is placed on the fork 15. The first sensor 25 is connected to the base 2 of the fork 15.
It is constituted by a lever switch having a lever 26 which extends from 2 toward the front and downward.

Further, as shown in FIG. 3, each of the forks 15 is provided with four second sensors 2 in this embodiment to detect the position of the front end 27 of the load 23 on the forks 15.
8 are arranged at equal intervals along the fork 15. Each of the second sensors 28 is constituted by a limit switch having an operating piece 29 protruding from the upper surface of the fork 15.

In the functional product room 12, the center position of the load 23 is calculated from the detection results of the first sensor 25 and the second sensor 28, and the center position of the load 23 when the load 23 is placed on the shelf. So that the fork 1 is positioned at the center of the storage surface of the shelf
5 is provided with a control device 30 for controlling the reach amount. Further, the functional product room 12 detects the amount of reach of the fork 15 and the mast 14 and constantly outputs the result to the control device 3.
A reach reel sensor 31 for transmitting to 0 is provided.

Next, the operation of the reach type unmanned forklift 11 configured as described above will be described. Load 23
Is received on the fork 15, the fork 15 and the mast 14 are first advanced along the reach rail in the reach leg 16 until the rear end 24 of the load 23 comes to the base of the fork 15. At this time, the timing at which the forward movement of the fork 15 is stopped is when the lever switch is turned ON. That is, when the fork 15 is reached, the load 23 relatively moves to the root portion 22 of the fork 15.
, The rear end 24 of the load 23 moves from the position indicated by the solid line to the position indicated by the dotted line in FIG.
Is turned to the dotted line position, and the lever switch is turned ON. Thus, the forklift 11 receives the load 23 at the base of the fork 15.

When the load 23 is placed on the fork 15,
Depending on the size of the load 23, some of the plurality of limit switches are turned on by the operation piece 29 being pressed by the bottom surface of the load 23.
State. The limit switch having no load 23 on the operation piece 29 remains OFF. That is, as shown in FIG. 3, when the front end 27 of the load 23 is located between the second limit switch and the third limit switch from the base of the fork, the first and second limit switches from the base of the fork are ON, and the third and fourth limit switches are OFF. Such information is
It is sent to the control device 30. The control device 30 is programmed in advance so that the position of the front end 27 of the load 23 can be determined from the number of the limit switches that are turned ON, so that the rear end 24 and the front end 24 of the load 23 in the control device 30. The size of the load 23 is detected from the position of the
Is detected in the front-rear direction.

Thereafter, when storing the load 23 on the target shelf, first, the reach type unmanned forklift 11 moves to the front of the target shelf and stops. For this, an existing method for controlling the movement of vehicles in an unmanned warehouse is used. Subsequently, the fork 15 is raised to the height of the storage surface of the shelf, and the fork 15 is reached such that the center position of the load is located at the center of the storage surface of the shelf. At this time, fork 15
Is controlled by the control device 30 as follows.

As shown in FIG. 4, first, in step S
The number of limit switches turned ON as 1 is checked, and the center position of the load 23 is calculated. In step S2, since the stop position of the vehicle is predetermined, the load 23
The target reach amount is calculated based on the distance from the center position of the shelf to the center of the storage surface of the shelf. Next, the fork 15 is made to reach and move forward in step S4 until it is determined in step S3 that the reach amount obtained from the reach reel sensor 31 has reached the target reach amount. When the reach amount reaches the target reach amount, the reach operation of the fork 15 is stopped in step S5.

In this manner, as shown in FIGS. 5 and 6, the load 23 is positioned such that the center position G of the load 23 is located at the center O of the storage surface (the virtual surface indicated by the dotted line) of the shelf 32. Shelf 3
Put on top of 2. Therefore, the state in which the load 23 is placed on the shelf 32 is more stable than in the related art.

Embodiment 2 In the reach type unmanned forklift according to Embodiment 1, a photoelectric switch may be used instead of the limit switch. That is, in such a structure, a hole through which light passes is formed in the upper surface of the fork just above each photoelectric switch, and when the load 23 is placed on the fork 15, the hole is closed by the bottom surface of the load 23. Then, the light is shut off and the photoelectric switch is turned on. The photoelectric switch in the portion where the load 23 is not placed remains in the OFF state. Thus, the position of the front end 24 of the load 23 can be detected as in the case of the limit switch.

In addition, according to this configuration, there is an advantage that an operating piece protruding from the upper surface of the fork becomes unnecessary. That is, in the case of the limit switch, the operating piece 29 protrudes from the upper surface of the fork 15, but in the case of the photoelectric switch, it can be accommodated within the thickness of the fork, and has a structure that is strong against lateral stress. You do not need to be conscious.

Other Embodiments Further, the second sensor of the reach type unmanned forklift of the present invention is not limited to the limit switch and the photoelectric switch described in the above embodiment, but may be another mechanically operated sensor or an optically operated sensor. Can also be used. The number of the second sensors is 4 in the above embodiment.
Although the number is individual, it is not limited to this, and more may be provided. As the number of second sensors is increased and the distance between adjacent second sensors is reduced, the front end 27 of the load 23
The detection accuracy of the position can be improved.

Since the size of the load 23 on the fork 15 can be detected by using the first sensor 25 and the second sensor 28 as described above, a large load can be detected based on the result. About 23 may be stored in the lower part of the shelf. According to such an embodiment, the center of gravity of the shelf storing the load 23 is located lower, so that the stability of the shelf is further improved.

[0024]

As described above, according to the reach type unmanned forklift of the present invention, it is possible to detect the size of the load and store the load so that the center position of the load is located at the center of the shelf. Because of this, the stability of shelves containing loads is improved.

[Brief description of the drawings]

FIG. 1 is a side view of a reach type unmanned forklift according to Embodiment 1 of the present invention.

FIG. 2 is a side view of a fork portion of the reach type unmanned forklift according to Embodiment 1 of the present invention.

FIG. 3 is a plan view of a fork portion of the reach type unmanned forklift according to Embodiment 1 of the present invention.

FIG. 4 is a flowchart related to automatic control of a reach amount by a control device.

FIG. 5 is a front view of a shelf in which a load is stored by the reach type unmanned forklift according to the present invention.

FIG. 6 is a side view of a shelf in which a load is stored by the reach type unmanned forklift according to the present invention.

FIG. 7 is a side view of a conventional reach type unmanned forklift.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 13 Reach part 14 Mast 15 Fork 16 Reach leg 22 Root part 23 Load 24 Rear end 25 First sensor 26 Lever 27 Front end 28 Second sensor 29 Working piece 30 Control device

Claims (5)

[Claims] 1. A fork provided to be able to move up and down along a mast, a reach portion for moving the mast along the front-rear direction of a vehicle, and a center position of a load on the fork provided in the fork in the front-rear direction. Center detecting means for detecting, and when the load is stored on the shelf, the reach amount of the fork by the reach portion is adjusted so that the center position of the load obtained from the center detecting means is located at the center of the storage surface of the shelf. A reach type unmanned forklift equipped with a control device for controlling. 2. A center sensor, comprising: a first sensor provided at the root of the fork to detect whether a rear end of the load is positioned at the root of the fork; The reach-type unmanned forklift according to claim 1, further comprising a plurality of second sensors arranged along the fork to detect a position. 3. The reach type unmanned forklift according to claim 2, wherein the first sensor comprises a lever switch provided with a lever which is operated by the load when the load is loaded to the base of the fork. 4. The reach type unmanned forklift according to claim 2, wherein each of the second sensors comprises a limit switch having an operation piece that protrudes from the upper surface of the fork and is pressed by a bottom surface of the load. 5. The reach type unmanned forklift according to claim 2, wherein each of the second sensors comprises a photoelectric switch.