JP2009001380A - Stacker crane and its operating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stacker crane operating method capable of enhancing the space efficiency of an automated warehouse. <P>SOLUTION: In the stacker crane operating method for moving a stacker crane along a rack in an automated warehouse, the stacker crane has a transfer means which loads an article on a loading stand and is retracted from the stacker crane to transfer the article. The stacker crane operating method includes a loading step (S13-S16) for loading the article at the position close to the side of the rack on the loading stand. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stacker crane and an operation method thereof, and more particularly to a technique for improving space efficiency of an automatic warehouse.

  2. Description of the Related Art Conventionally, automatic warehouses that store articles in racks and take out articles from racks using stacker cranes that automatically run have been widely put into practical use. The rack is provided with a plurality of shelves for storing articles in a row in the vertical and horizontal directions.

  In such an automatic warehouse, a rack is configured to store a plurality of articles in the depth direction of one shelf, and a plurality of lifters are provided on the slide fork of the stacker crane 1 so as to be individually raised and lowered. A technique for controlling exit / exit and raising / lowering of individual lifters is well known (for example, see Patent Document 1).

According to this configuration, articles can be loaded one by one from adjacent shelves and a plurality of articles can be delivered at a time. For example, if this technology is applied to a parts warehouse, it can be used in pairs or groups. Multiple types of parts can be combined in an automatic warehouse and delivered together.
JP 2002-187603 A

  According to the prior art, since articles are transferred using a slide fork with a plurality of lifters that can be individually controlled to move up and down, a relatively large space for inserting such a slide fork is provided for each article. It is necessary to secure it corresponding to. Therefore, there is a problem that the space efficiency of storage is reduced instead of obtaining the convenience that a plurality of articles can be delivered in a desired combination.

  On the other hand, depending on the operation policy of the automatic warehouse, the space efficiency of storage is often considered more important than the convenience of leaving. However, the conventional technology cannot take effective measures for improving the space efficiency of storage.

  This invention is made | formed in view of such a situation, and it aims at providing the stacker crane which can improve the space efficiency of storage of an automatic warehouse, and its operating method.

  In order to solve the above-mentioned problem, there is provided a method of operating a stacker crane that moves along a rack in an automatic warehouse, wherein the stacker crane moves an article by placing the article on a mounting table and withdrawing from the stacker crane. A loading step of placing the article at a position close to the rack side on the placing table.

  According to this configuration, since the amount of advancement of the transfer means required when transferring an article is small, the transfer means can be configured to be thinner. For example, when the transfer means is a slide fork composed of a plurality of plates, the slide fork can be composed of a smaller number of plates.

  By reducing the thickness of the transfer means, the entry area of the transfer means that must be secured for each article is uniformly reduced, so that the storage space efficiency is improved.

  In particular, in a situation where a large amount of advancement is required for the transfer means at the time of transfer of articles, such as storing a plurality of articles in one shelf along the exit / retreat direction of the transfer means, an inherently thick transfer is required. Since the loading means is used, the effect of thinning the transfer means by applying this configuration is great.

  More preferably, in the previous placing step, the article may be placed at a position where the end of the placing table on the rack side and the end of the article are aligned.

  According to this configuration, it is not necessary to provide a clearance for avoiding the interference of the transfer means at the rear of the article, so that the storage space can be used up without waste.

  Further, in the automatic warehouse, racks are provided on both sides of the path of the stacker crane, and a station for placing articles to be stored on at least one side of the path is provided, and the operation method is further placed in the station. Including a specifying step for specifying a rack for storing the article, and in the setting step, the loading unit is advanced from the station by moving the transfer means by an amount corresponding to the specified rack from the stacker crane. The article may be transferred to a position close to the specified rack.

  According to this configuration, since the placement position of the article can be changed simply by controlling the advancement amount of the transfer means, an effect of improving the storage space efficiency can be obtained without adding a special mechanism. Can do.

  In addition, the present invention can be realized not only as such an operation method but also as a stacker crane including a control unit that controls the slide fork according to such an operation method.

  As described above, according to the stacker crane operating method of the present invention, the article is placed on the transfer means at a position close to the rack storing the article. The amount of advancement of the transfer means that is sometimes required is small, and as a result, the transfer means can be made thinner.

  By reducing the thickness of the transfer means, the entry area of the transfer means that must be secured for each article is uniformly reduced, so that the storage space efficiency in the automatic warehouse is improved.

  A stacker crane and an operation method thereof according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing an example of a configuration of an automatic warehouse in the embodiment. The automatic warehouse shown in FIG. 1 includes a stacker crane 1, a rack 2 provided along a path of the stacker crane 1, and a station 3 on which articles are placed at the time of loading and unloading. The rack 2 is provided with a plurality of shelves for storing articles vertically and horizontally.

  The rack 2 may be provided on the opposite side across the passage of the stacker crane 1.

  FIG. 2 is a diagram schematically illustrating an example of the configuration of the stacker crane 1. FIG. 2 corresponds to a left side view of the automatic warehouse of FIG. Here, it is assumed that racks 2 are provided on both sides of the path of the stacker crane 1. For convenience, the rack on the right side of the drawing is called a right rack 2R, and the rack on the left side is called a left rack 2L.

  The stacker crane 1 includes a casing formed by connecting a lower carriage 11 and an upper carriage 12 with a mast 13, a lifting platform 16, and a control device 23.

  A wheel 14 for traveling on the rail 4 laid on the floor and a traveling motor 15 for driving the wheel 14 are attached to the lower carriage 11.

  On the mast 13, a lifting platform 16 is mounted so as to be movable up and down, and a winch motor 17 is mounted. The elevator 16 is suspended by a wire rope 19 guided by a sheave 18 and moves up and down the mast 13 according to the operation of the winch motor 17.

  The elevator 16 is provided with a slide fork 20. The slide fork 20 includes a plurality of plates 21 that are connected to each other so as to be able to move back and forward, and a transfer motor 22 that moves the plates 21 out and out of the lifting platform 16. The uppermost plate 21 functions as a mounting table on which articles are mounted. Here, the slide fork 20 is an example of transfer means described in the claims.

  The control device 23 controls operations of the traveling motor 15, the winch motor 17, and the transfer motor 22.

  The stacker crane 1 travels on the rail 4 to a desired shelf of the rack 2 or the station 3 under the control of the control device 23, moves the elevator 16 up and down, and moves the slide fork 20 in and out to move the elevator 16 The article is transferred between the rack 2 and the station 3.

  FIG. 3A is a view conceptually showing the slide-out mechanism of the slide fork 20.

  The plurality of cam followers 24 provided on the base plate 21B engage with the first linear motion guide grooves 25 provided on the middle plate 21M. The plurality of cam followers 26 provided on the top plate 21T engage with the second linear motion guide grooves 27 provided on the middle plate 21M. Thereby, the base plate 21B, the middle plate 21M, and the top plate 21T are connected to each other so as to be able to move backward.

  The pinion 28 attached to the base plate 21B meshes with a rack 29 provided on the middle plate 21M. When the transfer motor 22 drives the pinion 28, the middle plate 21M is pushed out from the base plate 21B in either the left or right direction and is pulled in.

  The pinion 30 provided on the middle plate 21M meshes with a rack 31 and a rack 32 provided on the base plate 21B and the top plate 21T, respectively.

  As a result, the top plate 21T is pushed out of the middle plate 21M by the same amount as the middle plate 21M is pushed out from the base plate 21B and pulled in. In other words, the top plate 21T moves relative to the base plate 21B at twice the speed of the middle plate 21M.

  By stacking this mechanism, a slide fork having four or more plates can be configured.

  FIG. 3B is a diagram conceptually showing another exit / retreat mechanism of the slide fork 20. In this exit / retreat mechanism, the following configuration is provided instead of the pinion 30, the rack 31, and the rack 32 shown in FIG.

  That is, the sprocket 33 and the sprocket 34 are attached to the middle plate 21M. A chain 35 (shown by a thick solid line) that meshes with the sprocket 33 is locked to the base plate 21B and the top plate 21T by a locking tool 36 and a locking tool 37, respectively. Further, a chain 38 (shown by a thick broken line) that meshes with the sprocket 34 is locked to the base plate 21B and the top plate 21T by the locking tool 39 and the locking tool 40, respectively.

  Also in this configuration, similarly to the configuration of FIG. 3A, the top plate 21T is pushed out of the middle plate 21M and pulled in by the same amount as the middle plate 21M is pushed out of the base plate 21B.

  Next, a typical example of the conventional design of the positional relationship between the slide fork and the shelf when a plurality of articles are stored in one shelf along the depth direction of the rack will be described.

  4 (A), 4 (B), and 4 (C) are diagrams showing such typical examples. For convenience of understanding, hypothetical dimension values are shown. The unit of the numerical value may be, for example, millimeter.

  FIG. 4A shows a state in which the slide fork is drawn into the stacker crane. A rack having a depth of 1600 is provided adjacent to a passage of a stacker crane having a width of 1600. Here, the depth refers to the slide-out direction of the slide fork, and corresponds to the left-right direction of the paper. Illustration of the left rack is omitted.

  By dividing the storage area in the depth direction of the rack, a front shelf area and a back shelf area each having a depth of 800 are set. A slide fork entry area is secured below the front shelf area and the back shelf area.

  The slide fork is composed of a top plate having a depth of 800 and three middle plates and a base plate each having a depth of 1200 in order from the top. Each plate is drawn into the stacker crane with the center position aligned. The cam follower interval (hereinafter referred to as a fulcrum pitch) is 400.

  FIG. 4B shows a situation where an article is transferred to the front shelf area. By pushing the lowermost middle plate from the base plate by a distance of 300, the slide fork is pushed out by a distance of 1200 as a whole, and the top plate is positioned in the front shelf area.

  FIG. 4C shows a situation where an article is transferred to the back shelf area. By pushing the lowermost middle plate at a distance of 500 from the base plate, the slide fork is pushed out by a distance of 2000 as a whole, and the top plate is positioned in the back shelf area.

  Now, considering the improvement of the space efficiency of storage with respect to the typical positional relationship between the slide fork and the shelf, several problems become apparent.

  First, consider reducing the slide fork entry area by reducing the size of the slide fork in the height direction (referred to as the thickness), thereby reducing the pitch in the height direction of the shelf and improving space efficiency. To do.

  FIG. 5 is a diagram for explaining a problem that occurs when a slide fork is configured with four plates to reduce the thickness. As shown in FIG. 5, by setting the advance amount per plate to 666.7, the top plate can be positioned in the back shelf area.

  However, since the depth of the portion where the top plate and the upper middle plate intersect is reduced to 333.3, it is impossible to secure 400 fulcrum pitches. For this reason, depending on the weight of the article, the reaction force exceeds the limit value, resulting in insufficient strength, so this configuration cannot be employed.

  Therefore, it is considered to secure the fulcrum pitch.

  FIG. 6A and FIG. 6B are diagrams for explaining a problem that occurs when the depth of the top plate is set to 1200, which is the same as that of the middle plate or the base plate, in order to ensure the fulcrum pitch.

  FIG. 6A shows a situation where an article is transferred to the front shelf area. The depth of the front shelf area is set to 800, and the rear shelf area is set with a clearance of depth 200 from the front shelf area in order to avoid interference with the top plate.

  FIG. 6B shows a situation in which an article is transferred to the back shelf area set as described above. As shown in FIG. 6 (B), by setting the advance amount per plate to 733.3, the top plate can be positioned in the back shelf region and 400 fulcrum pitches can be obtained.

  However, in addition to the clearance at the rear part of the front shelf area, the depth of the rack becomes 2000 because the clearance at the rear part of the rear shelf area is taken, and the installation area of the rack is wasted. This is contrary to the purpose of improving the space efficiency of storage.

  Thus, although some attempts to improve the space efficiency of storage can be considered, all of them are ineffective. Therefore, the conventional typical design as shown in FIGS. 4A to 4C is maintained.

  Therefore, in the stacker crane and its operation method according to the present invention, in order to overcome the above-described problems and improve the space efficiency of storage, the article is placed at a position close to the rack side of the top plate.

  In addition, the shelf for storing the articles placed in the station is identified, and the amount of advancement of the slide fork is controlled according to which side of the stacker crane is located in the rack of the stacker crane. The article may be placed at a position close to the specified shelf.

  The details of the operation of such a stacker crane will be described below.

  FIG. 7 is a flowchart showing an example of a method for operating the stacker crane in the present embodiment. The flowchart of FIG. 7 will be described with reference to the configuration of FIG.

  When detecting that the article has arrived (S10), the control device 23 drives the traveling motor 15 and the winch motor 17 to move the elevator 16 to the station 3 (S11). The arrival detection of an article can be performed based on, for example, a notification from a sensor provided in the station 3 or a notification from a host computer that manages the entire activity of the automatic warehouse.

  The control device 23 specifies a shelf for storing the arrived articles (S12). The identification of the shelf may be performed, for example, by reading information on the shelf recorded in advance on the IC tag attached to the article or by inquiring of the host computer. Then, it is determined whether the specified shelf is in the right rack 2R or the left rack 2L (S13).

  When the control device 23 determines that the shelf is in the right rack 2R (the rack in the right rack in S13), the control device 23 drives the transfer motor 22 to advance the slide fork 20 by a first amount (S14). If it is determined that the shelf is in the left rack 2L (the shelf of the left rack in S13), the slide fork 20 is advanced by a second amount by driving the transfer motor 22 (S15).

  FIGS. 8A and 8B are diagrams illustrating an example of the advance position of the slide fork when an article is transferred from the station to the top plate. For convenience of understanding, hypothetical dimension values contrasted with FIG. The unit of the numerical value may be, for example, millimeter.

  A station which is an entry / exit area having a depth of 800 is provided adjacent to a passage of a stacker crane having a width of 1600. On the opposite side of the station from the stacker crane passage, a clearance having a depth of 400 is set to avoid interference with the slide fork. The center of the loading / unloading area is located at a distance 1200 from the center of the stacker crane passage, similar to the center of the front shelf area described above. Articles to be stored on the shelves are placed in this entry / exit area.

  Each slide fork is composed of a top plate having a depth of 1200, two middle plates, and a base plate. The fulcrum pitch is 400. This configuration is the same as the slide fork shown in FIGS. 6 (A) and 6 (B), and has one fewer plate than the slide fork shown in FIG. 4 (A).

  FIG. 8A shows a situation where articles are transferred from the station to the top plate when it is determined that the storage rack is in the right rack 2R.

  By pushing the lowermost middle plate from the base plate at a distance of 333.3, the slide fork is pushed out as a whole by a distance of 1000, and the top plate is positioned at a position where the right end is aligned with the right end of the loading / unloading area. This distance 1000 is an example of the aforementioned first amount.

  FIG. 8B shows a situation where an article is transferred from the station to the top plate when it is determined that the storage rack is in the left rack 2L.

  By pushing the lowermost middle plate from the base plate by a distance of 466.7, the slide fork is pushed out by a distance of 1400 as a whole, and the top plate is positioned at a position where the left end is aligned with the left end of the loading / unloading area. This distance 1400 is an example of the second amount described above.

  The control device 23 drives the transfer motor 22 to advance the slide fork 20 to the position shown in FIG. 8A or 8B, and drives the winch motor 17 to raise the lifting platform 16. Let As a result, the article placed on the station 3 is transferred to a position close to the right side (right rack 2R side) or the left side (left rack 2L side) of the top plate (S16).

  The control device 23 pulls the slide fork 20 into the lifting / lowering table 16 (S17), and drives the traveling motor 15 and the winch motor 17 to move the lifting / lowering table 16 to a shelf for storing articles (S18).

  Then, depending on whether the area for storing the article is the front shelf area or the back shelf area, the slide fork is advanced by the third amount or the fourth amount, and the article is transferred to the target area (S19 to S22).

  FIG. 9A and FIG. 9B are diagrams illustrating an example of the advance position of the slide fork when an article is transferred from the top plate to the shelf. The slide fork is moved a distance 1000 for transfer to the front shelf area. This distance 1000 is an example of the aforementioned third quantity. In addition, the slide fork is advanced by a distance 1800 for transfer to the back shelf area. This distance 1800 is an example of the aforementioned fourth amount. At this time, 400 fulcrum pitches are secured.

  Such an operation for the right rack is also executed symmetrically for the left rack.

  9A and 9B is compared with FIGS. 4B and 4C, the thickness of the slide fork is reduced by reducing the number of plates. Moreover, by placing the top plate at the same depth as the middle plate and the base plate, and placing the article at a position close to the rack side of the top plate, the front shelf can be formed with a small number of plates while maintaining the fulcrum pitch. The article can be transferred to the area and the back shelf area.

  6A and 6B, the end of the article can be placed so as to be aligned with the rack side end of the top plate. It is not necessary to take the clearance at the rear of the area, and as a result, the rack installation area can be used up without waste.

  Therefore, according to the stacker crane and its operation method of the embodiment, the pitch in the height direction of the shelf can be shortened by reducing the thickness of the slide fork without causing waste in the installation area of the rack. Efficiency is improved.

  Such an operation method exhibits a good effect when the depth of the top plate is shorter than the depth of the rack, particularly when racks are provided on both sides of the stacker crane passage.

  On the other hand, if the depth of the top plate is longer than the depth of the rack, slide the article when transferring the article from the station to the top plate by placing the article on the rack opposite to the station on the top plate. Since the fork advancement amount is larger than the slide fork advancement amount when transferring goods from the top plate to the rack, the advancement amount of the slide fork is not optimized, which is disadvantageous for reducing the slide fork thickness. May be.

  Therefore, as described in the embodiment, the depth of the top plate is configured to be shorter than the depth of the rack, and a plurality of storage areas (for example, the front shelf area and the back shelf area described above) along the depth direction of the rack. Setting is effective. Therefore, the automatic warehouse and the operation method including the rack and the stacker crane configured as described above are also included in the present invention.

  As described above, the stacker crane of the embodiment and the operation method thereof have been described using hypothetical numerical values for the convenience of understanding. However, it will be appreciated that the present invention is not limited by the stacker crane, slide fork, plate, rack, and station depth dimensions. The present invention is generally characterized by a technique for placing an article near a rack on a transfer device.

  The stacker crane according to the present invention and the operation method thereof can be used, for example, in an automatic warehouse.

The perspective view which shows an example of a structure of the automatic warehouse in embodiment The figure which shows an example of a structure of a stacker crane typically (A) And (B) The figure which shows notionally the withdrawal and withdrawal mechanism of a slide fork The figure which shows an example of the conventional advance position of (A), (B), and (C) slide fork. Diagram explaining the problem that occurs when a slide fork is configured with a small number of plates The figure explaining the problem which arises when (A) and (B) fulcrum pitch is secured. The flowchart which shows an example of the operation method of the stacker crane in embodiment (A) And (B) The figure which shows an example of the advance position of the slide fork at the time of transfer from a station (A) And (B) The figure which shows an example of the advance position of the slide fork at the time of transfer to a shelf

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stacker crane 2 Rack 2R Right rack 2L Left rack 3 Station 4 Rail 11 Lower trolley 12 Upper trolley 13 Mast 14 Wheel 15 Traveling motor 16 Lifting base 17 Winch motor 18 Sheave 19 Wire rope 20 Slide fork 21 Plate 21B Base plate 21M Middle plate 21T Top plate 22 Transfer motor 23 Control device 24, 26 Cam follower 25, 27 Linear motion guide groove 28, 30 Pinion 29, 31, 32 Rack 33, 34 Sprocket 35, 38 Chain 36, 37, 39, 40 Locking tool

Claims (4)

An operation method of a stacker crane that moves along a rack in an automatic warehouse,
The stacker crane has transfer means for transferring the article by placing the article on a mounting table and moving out of the stacker crane.
An operation method comprising: a placement step of placing the article at a position on the placement table that is close to the rack. 2. The operation method according to claim 1, wherein the article is placed at a position where the rack-side end of the placement table and the end of the article are aligned in the placement step. In the automatic warehouse, racks are provided on both sides of the path of the stacker crane, and a station for placing articles to be stored on at least one side of the path is provided,
The operation method further includes:
A specific step of identifying a rack for storing articles placed in the station,
In the previous placement step, the transfer means is advanced from the stacker crane by an amount corresponding to the specified rack, thereby moving the station closer to the specified rack on the mounting table. The operation method according to claim 1, wherein the article is transferred. A stacker crane that moves along a rack in an automatic warehouse,
A transfer means for transferring the article by placing the article on a mounting table and moving away from the stacker crane;
A stacker crane comprising: control means for placing the article at a position close to the rack side on the mounting table by advancing the transfer means by a predetermined amount from the stacker crane.

Images