JPH07157012A - Stop control device for stacker crane - Google Patents

Abstract

PURPOSE:To prevent the deviation from the allowance range of a stop due to the fluctuation of a stop position by reducing an allowance range, in checking a shilding plate at the time of the travel stop of a stacker crane in an automatic warehouse, than that in checking after travel stop. CONSTITUTION:An optical sensor, for detecting the front part shielding plates 20, 21 ... of a stacker crane, or a proximity sensor, etc., is arranged, and the shielding plates 20, 21 ... have length in the respective allowance ranges in accordance with frontage centers to be stop points every frontage of a rack shelf. The sensor detects a braking start position by whether the shielding plate 21 of the stacker crane stops within a range or not. The length L1 of the shielding plate 20 is made stop at a position nearer as possible to a stop point in a small allowance range within an allowance range at the time of travel stop. The length L2 of the plate 21 is lengthened in before and aft than the length L1 of the shielding plate 20, and the allowance range of position fluctuation after stopping is increased to allow position fluctuation caused vibration, etc., after stopping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control mechanism for stopping a stacker crane for loading and unloading luggage in an automatic warehouse at a desired rack position.

[0002]

2. Description of the Related Art In an automatic warehouse, a stacker crane is arranged so as to run between a rack and a loading / unloading station, and a slide fork mounted on a lifting platform loads / unloads cargo to / from each rack rack or loading / unloading station. It is supposed to do. For example, when loading a load on a rack shelf with a slide fork, it is always necessary to check whether the stacker crane is located at the center of the shelf so that the load and the slide fork do not hit the rack. Therefore, a shield plate with a predetermined length (allowable range) is placed at a position corresponding to the center of the frontage, which is a stop point on the side of the traveling rail, and a sensor for detecting the shield plate is provided on the stacker crane side to drive the vehicle. The stop position is always monitored not only when the vehicle is stopped but also after the vehicle is stopped. Specifically, the stacker crane is run toward a desired shelf, and as shown in FIG. 5, when a predetermined shield plate 20 'is detected, a timer is activated and the stacker crane is stopped after T seconds. . At this time, it is checked whether or not the stop position is within the allowable range, that is, whether or not the shield plate 20 'is detected. If the stop position is displaced and the shield plate 20' is not detected, the shield plate 20 'is detected. It will run again (retry) toward 'and stop within the allowable range. Further, when the slide fork is being driven after the traveling is stopped, the stopping position is displaced due to backlash or vibration of the traveling drive chain, and the shield plate 20 '
If the operation is not detected, luggage and slide forks may hit the rack if the operation is continued, so all operations of the stacker crane are immediately stopped.

[0003]

In recent years, as the speed of stacker cranes has increased, the stop position has become more and more variable, and there is a possibility of stopping at a position where the shield plate 20 'can be detected. Is getting higher. When the shield 20 'is stopped at a position where it cannot be detected, the retry operation is automatically performed. However, the shield 20' is stopped at a position where it can be detected, After that, when the stop position is deviated, all the operations of the stacker crane are stopped, and it is necessary to manually restore the stacker crane, which is very troublesome.

[0004]

The present invention is configured as follows in order to solve the above problems. That is, the traveling stop position is checked by the position detector provided on the stacker crane, and when the vehicle is out of the stop range at the time of stop, the vehicle is re-traveled toward the stop point, and when it is out of the stop range after the stop, the crane is moved. A stop control device for stopping the operation, wherein an allowable range for checking when traveling is stopped is smaller than an allowable range for checking after traveling is stopped.

[0005]

By using such means, when traveling is stopped, the check is made within a relatively small allowable range,
After traveling is stopped, a check is made within a relatively large allowable range. Therefore, even if the vehicle stops at a position just within the permissible range when the traveling is stopped and the stop position is slightly shifted after the traveling, the permissible range after the traveling is stopped is not exceeded.

[0006]

The problems and solutions to be solved by the present invention are as described above, and the structure of the embodiments will be described with reference to the accompanying drawings. 1 is a side view of a stacker crane, FIG. 2 is a perspective view of a shield plate detection unit, FIG. 3 is a view showing a stop detection range,
FIG. 4 is a diagram showing another embodiment.

In FIG. 1, a stacker crane S installed in an automated warehouse comprises a traveling rail 14 laid on the floor,
It is provided so as to be able to travel back and forth between the traveling rail 14 and an upper guide rail arranged on the ceiling portion in parallel.
The stacker crane S has a structure in which a front mast 11 and a rear mast 12 are erected in front of and behind a traveling body 8 placed on a traveling rail 14, and an upper frame 7 is fixed to the upper ends of the front mast 11 and the rear mast 12. And the traveling drive wheels 15 and the driven wheels 16 are arranged at the lower front and rear of the traveling body 8,
A drive box 3 is placed on the front part of the traveling body 8, and a traveling motor M1 with a brake and a lifting motor M2 are arranged in the drive box 3. Motor M1 for running
The traveling drive wheel 15 is driven by the traveling rail 14
The upper and lower parts can be moved forward and backward, and the elevating motor M2 can elevate and lower the elevating table 1 arranged between the front mast 11 and the rear mast 12 by rotating the chain 10.

A slide fork 2 is arranged on the center of the lift table 1 so that the luggage W can be placed thereon, and the slide fork 2 can be slid to the left and right by a slide motor provided on the lift table 1. . A front support body 5 is provided upright on the front side of the lifting platform 1, and a rear support body 6 is provided upright on the rear side thereof, and guide rollers 9 are provided on the front surface of the front support body 5 and the rear surface of the rear support body 6, respectively.
・ The front mast 1 is raised and lowered by pushing 9 ...
1 and the rear mast 12 are guided.

A position detector for detecting a predetermined position of the traveling body 8 of the stacker crane S, for example, a shield plate 20, 21, 22, ... As sensors 23, 24, and 25, the position detector is composed of an optical sensor such as a photo interrupter capable of detecting a plate, a proximity sensor, or the like. The sensors 23, 24, 25 have recesses formed in the lower portion to serve as detecting portions, and the respective detecting portions are arranged in parallel downward and are arranged in parallel with each other.
22 ... are turned on when they are located in the detection unit, and are connected to the control circuit of the stacker crane S, and the control circuit includes a traveling motor M1 and a lifting motor M.
2 and slide motors are also connected.

The shielding plates 20, 21, 22 ... Are shown in FIG.
As shown in FIG. 2, the sensor 23, which is parallel to the traveling direction of the stacker crane S, is placed on the floor on the side of the traveling rail 14.
The recesses 24 and 25 are arranged so that they can pass through, and each rack shelf is provided with a permissible length corresponding to the front center of the rack serving as a stop point. 23 is a shield plate 20 and a sensor 24
The shielding plate 21 and the sensor 25 are arranged corresponding to the shielding plate 22, respectively. Then, the sensor 23 detects the timer operation start timing when the traveling is stopped and whether or not it is stopped within the range of the shield plate 20 when stopped, and the sensor 24 is positioned within the range of the shield plate 21 after the stacker crane is stopped. The sensor 25 detects the braking start position.

Then, as shown in FIG. 3, the shielding plate 2
The length L1 of 0 is a permissible range when the vehicle is stopped, and is set as a relatively small permissible range so as to stop at a position as close as possible to the stop point. Also, make it longer in the front and rear, and make the allowable range of positional deviation after stopping relatively large, so that even if positional deviation occurs due to vibration etc. after stopping, some positional deviation is allowed unless it greatly deviates from the stop point. Is there.
These shielding plates 20 and 21 are arranged not only at the frontage of the rack but also at the loading / unloading station so as to stop the stacker crane S at a predetermined position.

With this configuration, the sensor 25 detects the shield plate 22 and starts braking to reduce the traveling speed of the stacker crane S, and the sensor 23 detects the shield plate 20 and stops after T seconds. If you want to do, check the sensor 23 when the stacker crane S is stopped,
If the sensor 23 is still ON, the stacker crane S is stopped at the center of the frontage of the target shelf, and if it is OFF, the stacker crane S is deviated from the center of the frontage. It is made to run toward the shield plate 20) arranged at the front of the shelf and stopped, and the process is repeated until it is accurately stopped. Then, after stopping at the front of the target shelf, it is constantly checked whether or not the sensor 24 detects the shield plate 21, and if it is ON, the work such as loading and unloading can be performed as it is, and if it is OFF, a position shift occurs. Therefore, all the operations of the stacker crane S are stopped because it becomes dangerous.
At this time, in the present invention, the permissible range after the stop is made larger than the permissible range at the time of stop, so that the stacker crane is rarely brought into the emergency stop in the normal work.

As another embodiment for checking the stop position of the stacker crane S and the position after the stop, a shield plate 22 is arranged at the deceleration start position as shown in FIG. A sensor 25 for detecting the shield plate 22 is arranged, and a detector 26 for detecting the traveling distance is further provided on the stacker crane S. The detector 26 is, for example, an encoder that rotates on the traveling rail 14 as the stacker crane S travels. The shield plate 22 is configured to detect the distance, and sets a permissible range L1 when the target position is stopped and a permissible range L2 after the stop that is wider than the permissible range.
The distance from is calculated in advance. When the stacker crane S is run and stopped at the target frontage,
When the sensor 25 detects the shield plate 22, deceleration starts,
At the same time, the detector 26 senses the distance and sets the set distance L3.
To stop at. At this stop, the shield plate 22 is actually
Compare (check) the distance traveled from and the preset distance L3, and if the difference is within the range of L1, work is continued,
If it is out of the range, the vehicle travels toward the target position again. After the stop, it is checked whether the difference is within the range of L2 and it is detected whether the difference is abnormal.

[0014]

Since the present invention is constructed as described above, it has the following effects. That is, the allowable range when checking the stacker crane when it stopped traveling was smaller than the allowable range when checking the stacker crane after stopping, so if the stacker crane is stopped within the allowable range of the desired shelf position, Even if there is a displacement after stopping due to a rush, etc., the displacement is relatively small, so it does not exceed the allowable range after stopping, and the crane does not stop unnecessarily during work such as loading and unloading. The work efficiency is no longer reduced.

[Brief description of drawings]

FIG. 1 is a side view of a stacker crane.

FIG. 2 is a perspective view of a shielding plate detection unit.

FIG. 3 is a diagram showing a stop detection range.

FIG. 4 is a diagram showing another embodiment.

FIG. 5 is a diagram showing a relationship between a conventional shield plate and stop control.

[Explanation of code] S Stacker crane 1 Lifting platform 2 Slide fork 20 ・ 21 Shielding plate 23 ・ 24 Sensor

Claims (1)

[Claims] 1. When the traveling stop position is checked by a position detector provided on the stacker crane, if the traveling position is outside the stopping range at the time of stopping, the traveling is performed again toward the stopping point, and if the traveling position is outside the stopping range after stopping. Is a stop control device for stopping the crane operation, wherein the allowable range for checking when traveling is stopped is smaller than the allowable range for checking after traveling is stopped. .