JPH1045210A - Stacker crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To arrange an object W always in a specified position on a lift table. SOLUTION: A slide fork 5 is attached to a table 8 which may slide in its width direction. When an object W is taken in with the slide fork 5, one set of centering members 15, 15 move in the closing direction and press the object W to center it at the specified position. The slide fork 5 moves together with the object W and when the centering action is over, secures the slide fork 5 by locking the rotation of a shaft 11 of a pinion 10 engaging with a rack 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stacker crane provided in an automatic warehouse, and more particularly to a stacker crane capable of minimizing a dead space of a rack.

[0002]

2. Description of the Related Art In a factory or a warehouse, a plurality of racks are arranged in a matrix in order to temporarily store products and workpieces. Automatic warehouses comprising stacker cranes for transporting articles have been put to practical use. An article transfer device is mounted on the elevator of the stacker crane, and transfers articles to and from racks and stations. The article transfer device is, for example, a hand for gripping an article or a slide fork for scooping an article from below.

In such an automatic warehouse, since articles are taken in and out by the article transfer device, an appropriate clearance is required for the rack. In the vertical direction, for example, when transferring goods with a slide fork, extend the slide fork and insert it below the article, raise the elevator slightly, scoop up the article, shrink the slide fork and take it on the elevator . Therefore, a clearance is required above the article. In the depth direction of the rack, which is the horizontal movement direction of the articles at the time of article transfer, a clearance corresponding to a variation in the stroke of each slide fork or the like is required. Regarding the width direction of the rack orthogonal to the moving direction at the time of article transfer, in order to cope with misalignment of the traveling stop position of the stacker crane and misalignment of the position of the article on the station when receiving the article from the station. Clearance is required.

[0004]

In order to store as many articles as possible in the same space and to make effective use of the space, it is preferable that such a clearance is minimized. Particularly in the width direction, since a large number of racks are arranged, even if the clearance can be reduced even by 1 cm, considerable space saving can be realized as a whole.
The problem of minimizing the clearance mainly depends on the stopping accuracy of the traveling vehicle, the lifting platform, and the slide fork. That is, if these devices stop almost exactly at a predetermined position, the clearance is minimal. For example, if the traveling vehicle has a stop accuracy of ± 0.5 mm, it is theoretically sufficient to provide a clearance of 0.5 mm in the width direction. However, if the stopping accuracy of the stacker crane is improved, it takes a long time to stop the stacker crane, which lowers the operating efficiency, complicates the stopping control method, and increases the scale of the control device. Also,
In addition to the type that simply retrieves articles that have been received, for example, there is an automatic warehouse that repeats the process of releasing the received articles to the station, picking a part, re-entering, re-exporting and picking, etc. In such an automatic warehouse where transport between racks or between racks and stations is repeated, accumulated errors occur even if the deviation is small each time. It had to be taken, and it was difficult to design how much clearance should be provided. Furthermore, if errors accumulate, it is detected as a collapse of the load. Each time, the stacker crane must be stopped to perform an abnormal processing operation, and as a result, the operation efficiency is adversely affected.

Accordingly, an object of the present invention is to minimize the clearance of the rack and minimize the dead space regardless of the accuracy of stopping the stacker crane, and to reduce the accumulated error due to continuous transfer. It is to provide a stacker crane that can eliminate the problem.

Another object of the present invention is to minimize the clearance in the width direction of the rack to minimize the dead space in the width direction regardless of the degree of stopping accuracy of the traveling vehicle, and to reduce the continuous space. It is an object of the present invention to provide a stacker crane that can eliminate accumulated errors in the width direction based on the transfer performed.

It is still another object of the present invention to provide a stacker crane that can correct the position in the width direction with a small-scale apparatus even for a heavy article.

[0008]

According to one aspect of the present invention, there is provided a stacker for moving articles on a front surface of a plurality of racks arranged in a matrix and transporting the articles to and from a station. In a crane, centering for horizontally moving articles transferred on an elevator by an article transfer device provided on the elevator of a stacker crane so as to be arranged at a predetermined position on the elevator. The stacker crane was configured with the means provided on the elevator.

According to a second aspect of the present invention, the centering means moves the article in a width direction which is a direction orthogonal to the moving direction of the article when the article is transferred by the article transferring apparatus. The stacker crane described in 1 was constructed.

According to a third aspect of the present invention, the article transfer device is movable and fixed in the width direction on the elevating table, and moves together with the article placed thereon at the time of centering by the centering means. And a slide fork fixed after the centering is completed.
Was constructed.

Since the present invention is configured as described above, the following effects are obtained.

The stacker crane according to the first aspect of the present invention travels and moves up and down on the front of a plurality of racks arranged in a matrix, and conveys articles between the racks and the stations. In order to transfer goods to and from the racks and stations, an elevating table is provided with an article transfer device. When an article is received from a rack or a station, the article is transferred by the article transfer device onto the elevator. The goods are
It is preferably located at a predetermined position on the lift (ie, a position where it is stored in a desired position on the rack or station when the articles are transferred from the position on the lift to the rack or station). Normally, when an article is transferred from a predetermined position on a lifting platform to a rack, the centers of the rack and the article in plan view overlap. So here,
Moving an article in a horizontal direction so as to be located at a predetermined position on a lift is referred to as centering. In the present invention, a centering means for performing centering is provided on the lift. That is, when the article is transferred on the lift platform, even if the article is at a position shifted from the predetermined position on the lift platform, it is moved in the horizontal direction by the centering means and placed at the predetermined position on the lift platform. You. When an article placed at a predetermined position on the elevating platform is conveyed and stored in a rack, it is stored at a desired position on the rack, so that the clearance in the horizontal direction of the rack can be minimized.

[0013] In the stacker crane according to the second aspect of the present invention, the centering means performs centering by moving the articles transferred on the elevator by the article transfer device in the width direction. The width direction is a horizontal direction and is a direction orthogonal to the direction in which the articles move when the articles are transferred by the article transfer apparatus. Therefore, when the articles are stored in the rack, the center lines of the articles and the rack in the width direction coincide with each other, so that the clearance in the width direction of the rack can be minimized.

[0014] In the stacker crane according to the third aspect of the present invention, the article transfer device mounted on the elevating platform is a slide fork. Transfer. The slide fork is movable and fixed in the width direction on the elevating table. When the article moves in the width direction at the time of centering by the centering means, it moves together with the article placed thereon. It is fixed after the centering is completed, and when the article is delivered in this state, the slide fork may be shifted in the width direction, but the article is centered. After delivering the article, the slide fork can be returned to its original position.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIGS. 1, 2, and 3 are a front view, a plan view, and a partially cutaway side view, respectively, showing an elevator of one embodiment of a stacker crane according to the present invention.

The elevator 1 is moved up and down along masts 2, 2 erected on a traveling carriage (not shown), and is constituted by rack columns 3, 3 and canches 4, and a plurality of racks arranged in a matrix. The article W is conveyed to a station (not shown). The lifting platform 1 is provided with a slide fork for transferring articles between a rack and a station. The operations of the traveling vehicle, the elevator 1, the slide fork 5, and a centering device described later are controlled by a control device attached to the traveling vehicle.

The slide fork 5 is not fixed to the lift base body 6 but is slidably mounted in the width direction via tables 8 attached to the linear guides 7. Further, racks 9, 9 are fixed to the bottom surfaces of the tables 8, 8, respectively.
9 meshes with the pinions 10, 10. Pinion 1
Both 0 and 10 are fixed to the shaft 11, and the shaft 11 is pivotally supported at both ends on the side of the elevator main body 6, so that when the slide fork 5 moves in the width direction, the shaft 11 rotates. The shaft 11 is provided with a clutch brake 12 for stopping rotation of the shaft 11. The other ends of the springs 13 each having one end attached to the lift base body 6 are attached to the left and right sides of each of the tables 8, 8 to urge each of the tables 8, 8 in a state where no load is applied. Thus, the center of the slide fork 5 is slid to a position that coincides with the center C in the width direction of the lift 1. A drive mechanism 14 for the slide fork 5 is suspended from the bottom of the slide fork 5. The width direction referred to here is the slide fork 5
, That is, a direction orthogonal to the direction in which the article W moves during transfer.

On the left and right sides of the slide fork 5, a pair of centering members 15, 15 are arranged. Each centering member 15 has an upper horizontal member 15a whose article W
1 (a pallet portion in FIG. 1). The horizontal member 15a is provided with a taper at both ends and an upper portion so that the article W can move smoothly even when the article W comes into contact with the article W when the article W moves. The centering members 15 and 15 are slidably attached to the lift base body 6 via linear guides 16 and 16 in the width direction, respectively. One ends of rods 17, 17 are rotatably attached to the centering members 15, 15, respectively. The other ends of the rods 17 and 17 are crank disks 1
8 is rotatably attached to the outer edge. The crank disk 18 is fixed to a shaft 19 that is supported by the lift base body 6.
Has been fixed. A belt 21 is wound around the driven pulley 20, and the belt 21 is also wound around a driving pulley 22. The drive pulley 22 is fixed to an output shaft of a drive motor 23 with a speed reducer. Therefore, the driving motor 2
When the 3 is driven, the crank disk 18 rotates and reciprocates the two rods 17, 17 in opposite directions, and moves in the width direction so that the centering members 15, 15 approach and separate from each other. I do. At this time, the position of each of the two centering members 15 is always equidistant from the center C in the left-right direction of the elevator 1. Photoelectric sensors 24, 25
Detects the position, posture, and height of the article W, respectively, and detects collapse of the load, abnormal height, and the like.

Next, the operation of this embodiment will be described.

First, in the initial state, that is, in a state in which the articles W are not loaded on the lift 1, the slide fork 5
After being centered by the bias of the spring 13, the clutch brake 12 is actuated and fixed to the center of the lift 1. Centering members 15, 15
Are separated from each other, that is, in an open position.
In this state, the traveling trolley, the lift 1 and the slide fork 5 operate, and the article W is placed on the slide fork 5 on the lift 1.

When the article W is taken into the elevator 1 by the slide fork 5, the clutch brake 12 is released, and the slide fork 5 can slide in the width direction. Next, the drive motor 23 is operated, and the centering members 15, 15 move in a direction approaching each other and close. As the door is closed, one of the centering members 15 contacts the side surface of the article W in the width direction. Further, when the centering members 15 and 15 are closed, the article W moves in the width direction by being pushed by the centering members 15 and 15 that are in contact with the article W. Since the slide fork 5 can also be moved in the width direction, the slide fork 5 on which the article W is placed moves with the movement of the article W. Since the article W moves with the slide fork 5 slidable in the width direction, it is not necessary to move the article W against the friction between the bottom surface of the article W and the upper surface of the slide fork 5 or the weight of the article W. A small-sized drive motor 23 and drive mechanism are sufficient.

When the centering members 15 and 15 are further closed, both centering members 15 and 15
, And the article W is sandwiched by the centering members 15, 15. As described above, since the two centering members 15, 15 are always equidistant from the center C, the center of the article W and the lift 1
Are centered with each other. When the end of centering is detected by an output of a sensor (not shown) for detecting the amount of movement of the centering members 15 or 15, or by an increase in the load on the drive motor 23, the drive motor
3 stops, the clutch brake 12 operates, and the slide fork 5 is fixed. In this state, the article W
Is centered, but since the slide fork 5 has moved together with the article W, it is deviated from the center, which is the initial position. If the center of the article W coincides with the center C of the lift 1 from the beginning by accident, the article W does not move even though the centering members 15 and 15 are closed, and the slide fork 5 also moves. Needless to say, it doesn't.

After the centering is completed, the slide fork 5
The traveling trolley moves up and down while the trolley 1 is moved up and down, and a rack where the article W is delivered and received is located in front of the elevator 1. The article W is delivered to the target rack by the slide fork 5, and at this time, the center of the article W, the center C of the elevator 1 and the center of the rack coincide with each other in the width direction. Delivered to match the center. When the article W is placed on the rack and the slide fork 5 is pulled into the elevating platform 1, the clutch brake 12 is released, the spring 15 is biased to center the slide fork 5, and the initial state is returned.

According to the stacker crane provided with the above-described elevator, the article W is arranged on the elevator with the center common to the elevator 1 in the width direction, so that the center of the article W coincides with the rack when it is delivered to the rack. Therefore, the clearance in the width direction of the rack can be minimized. Therefore,
Irrespective of the stopping accuracy of the traveling vehicle, the interval between the rack columns 3, 3 can be shortened, and the dead space can be minimized. In addition, no accumulated error occurs, and there is no need to provide rack clearance in consideration of the accumulated error. In addition, load collapse is not detected due to position shift,
The number of error handling operations is reduced.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be appropriately modified and implemented within the scope of the present invention.

For example, in the above-described embodiment, centering is performed only in the width direction, but centering may be performed in the depth direction along the traveling direction of the slide fork 5.

[0028]

As described above, according to the stacker crane according to the first aspect of the present invention, the clearance in the horizontal direction of the rack is minimized and the dead space is reduced irrespective of the accuracy of stopping the stacker crane. In addition to minimizing the number of times, it is possible to eliminate accumulated errors due to continuous transfer, and to reduce the number of times an abnormal processing operation must be performed when a load collapse is detected due to a positional shift.

According to the stacker crane according to the second aspect of the present invention, the clearance in the width direction of the rack is minimized and the dead space in the width direction is minimized regardless of the accuracy of stopping the traveling vehicle. While being able to
Accumulated errors in the width direction due to continuous transfer are eliminated, and the number of times that an abnormal processing operation must be performed when a load collapse is detected due to a displacement in the width direction is reduced.

According to the stacker crane according to the third aspect of the present invention, the position in the width direction can be corrected with a small-scale device even for a heavy article.

[Brief description of the drawings]

FIG. 1 is a front view showing a lifting platform portion of one embodiment of a stacker crane according to the present invention.

FIG. 2 is a plan view showing the same parts as in FIG. 1;

FIG. 3 is a partially cutaway side view showing the same part as FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lifting stand 5 Slide fork 8 Table 9 Rack 10 Pinion 15 Centering member

Claims (3)

[Claims] 1. A stacker crane which travels and raises and lowers a front surface of a plurality of racks arranged in a matrix and conveys articles to and from a station. A stacker crane, characterized in that the elevator has a centering means for performing centering for horizontally moving articles transferred to the elevator so as to be arranged at a predetermined position on the elevator. 2. The stacker crane according to claim 1, wherein the centering means moves the article in a width direction which is a direction orthogonal to a direction in which the article moves when the article is transferred by the article transfer apparatus. 3. The article transfer device is movable and fixable in the width direction on an elevator, and moves together with an article placed thereon when centering by the centering means, and is fixed after the centering is completed. The stacker crane according to claim 2, which is a slide fork.