JP2001206504A - Carrier conveyor and automated storage and retrieval system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier conveyor capable of improving working efficiency by improving carrying capacity and an automated storage and retrieval system using the conveyor. SOLUTION: In a carrier conveyor 12 having a unidirectional conveyor and a bidirectional conveyor and carrying articles such as pallets and packed articles, four bidirectional conveyors 14, 14a, 14b and 14c are arranged in a matrix-shape at all or a part of a corner part, a branching part and a joining part of the carrier conveyor 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conveyor for conveying articles such as pallets and packages at a distribution center or a distribution center, and an automatic warehouse system using the conveyor. The present invention relates to a transport conveyor capable of improving work efficiency and an automatic warehouse system using the same.

[0002]

2. Description of the Related Art FIG. 10 is an explanatory view showing an example of a conventional automatic warehouse system. The automatic warehouse system has an automatic warehouse storage shelf (hereinafter simply referred to as a storage shelf), and articles such as pallets and packages (hereinafter simply referred to as a pallet). ), And a main transport conveyor 12 for transporting pallets, for example, in the direction of the arrow.

The conveyor 12 includes a roller conveyor or a fixed chain conveyor 13 for conveying a pallet in one direction (hereinafter, simply referred to as a one-way conveyor) 13 and, for example, a vertically moving two-way conveyor unit or the like (in FIG. Are indicated by bold lines. Hereinafter, simply referred to as a two-way conveyor) 14 and the first and second transfer lines 12
a and 12b, and third and fourth transfer lines 12c and 12d connecting both ends of the transfer lines 12a and 12b in a loop, and the first to fourth transfer lines 12a and 12b. , 12c, and 12d advance by one step each.

[0005] Reference numeral 15 denotes a warehousing conveyor for branching the pallets conveyed by the conveyor 12 and carrying the pallets stored in the storage shelves 11 by the stacker crane 17. This is a delivery conveyer for transfer to the transport conveyor 12. Reference numeral 18 denotes a loading station which comprises, for example, a one-way conveyor and carries the pallets into the transport conveyor 12, and 19 denotes a shipping station which comprises, for example, a one-way conveyor and carries out the pallets transported by the transport conveyor 12.

[0005] Each corner of the conveyor 12, the conveyer 15 and the confluence of the receiving station 18 to the conveyor 12, and the exit conveyor 16 and the branch from the conveyor 12 of the shipping station 19, respectively, have two directions. A conveyor 14 is provided.

In the above-mentioned automatic warehouse system, for example, pallets received from the receiving station 18 are joined to the conveyor 12 by the two-way conveyor 14 at the junction, and are conveyed in the direction of the arrow to the two-way conveyor 14 at the branch. After that, it is sent to the receiving conveyor 15,
It is transferred to the stacker crane 17, carried into a predetermined position on the storage shelf 11, and stored. In addition, the pallets delivered from the delivery conveyor 16 join the transport conveyor 12 via the two-way conveyor 14 at the junction, are transported in the direction of the arrow, are sent to the shipping station 19 by the two-way conveyor 14 at the branch, and are shipped. .

Next, the pallet transfer operation at the corner of the transfer conveyor 12 of the automatic warehouse system as described above will be described in detail with reference to FIGS. (1) As shown in FIGS. 11A and 11B, the pallets 1, 2, 3,... Are transported on the first transport line 12a, and as shown in FIG. When reaching the two-way conveyor 14 at the corner, the first transport line 12a temporarily stops.

(2) Next, as shown in FIG. 11 (d), when the pallet 1 on the two-way conveyor 14 moves forward by one step and is transferred onto the third transport line 12c, FIG. 11 (e). ), The subsequent pallets 2, 3, 4,... On the first transport line 12a advance one step, and when the pallet 2 is positioned on the two-way conveyor 14, the first pallet 2
Is stopped again. At this time, the pallet 1 advances one step.

(3) Next, as shown in FIG.
When the pallets 2 on the two-way conveyor 14 are transferred onto the third transfer line 12c by moving the pallets 1 and 2 forward by one step, as shown in FIG.
., Advance one step, and when the pallet 3 is positioned on the two-way conveyor 14, the first transport line 12a
Stops. At this time, the pallets 1 and 2 on the third transport line 12c advance one step, respectively.

(4) Similarly, FIGS. 12 (b) and 12 (c)
, The pallets 4, 5, 6,... On the first transport line 12a are
Are sequentially sent to the third transport line 12c. In addition, pallets 1 up to the two-way conveyor 14
Are continuously transported on the first transport line 12a, but the pallets 1, 2, 3,... On the third transport line 12c passing through the two-way conveyor 14 are palletized back and forth. The sheet is conveyed after being opened by one sheet (hereinafter, the opened part is referred to as an empty part).

Although the pallet transfer operation at the corners of the transfer conveyor 12 has been described above, the convergence of the warehousing conveyor 15 and the receiving station 18 with the transfer conveyor 12, the unloading conveyor 16, and the transfer from the transfer conveyor 12 of the shipping station 19. The pallet conveying operation at the branching section is also performed according to the case of the corner section.

[0012]

In the conventional conveyor, the pallet temporarily stops at the time of merging and branching, so that the convergence part and the branch part of the conveyor become bottlenecks as frequent loading and unloading work, This has led to a decrease in overall work efficiency. In particular, when using a conveyor for entry and exit facilities of an automatic warehouse system, it is necessary to configure the conveyor in a loop shape or a U-shape,
In this case, since there are a plurality of corner portions, these portions have become a major bottleneck, and the overall work efficiency has been significantly reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a transport conveyor capable of improving work efficiency by increasing the transport capacity and an automatic warehouse system using the same. It was done.

[0014]

The transport conveyor according to the present invention has four bidirectional conveyors arranged in a cross in all or a part of a corner, a junction, and a branch.

In the above-mentioned conveyor, 4
Instead of two two-way conveyors, two two-way conveyors are arranged in the shape of a sun at all or a part of a corner, a branch, a junction, or the vicinity thereof.

Further, the conveyor according to the present invention comprises:
One or both of the third and fourth transport lines connecting both ends of the opposed first and second transport lines that constitute the transport conveyor are configured by two sets of one-way conveyors arranged side by side. It is.

Further, the automatic warehouse system according to the present invention comprises:
Any one of the above-mentioned conveyors is used as the conveyor.

[0018]

[First Embodiment] FIG. 1 is an explanatory view showing an example in which a transport conveyor according to a first embodiment of the present invention is used in an automatic warehouse system. Note that the same parts as those in the prior art described with reference to FIG.
Some description is omitted.

In this embodiment, two-way conveyors 14a and 14b are provided on the upstream and downstream sides of the two-way conveyor 14 at each corner of the conveyor 12 respectively, and the two-way conveyor 14c is provided inside each corner.
, Four four-way conveyors 14, 14a, 14b, 14c are arranged in a cross at the corners, and the merging portions and branching portions of the receiving stations 18a, 18b and the shipping stations 19a, 19b. Conveyors 14a and 14b are provided on the upstream side and the downstream side, respectively, and at the downstream corner of the junction formed by the two-way conveyors 14a and 14b, and at the upstream corner of the branch, respectively. By attaching the two-way conveyor 14c, four two-way conveyors 14, 14a, 14b, and 14c are arranged in a cross at the junction and the branch.

Next, the operation of transporting the pallets at the corners of the transport conveyor according to the present embodiment configured as described above will be described in detail with reference to FIGS. (1) As shown in FIGS.
Are continuously transported on the first transport line 12a, and the pallets 1 and 2 are transported by the two-way conveyors 14, 14a.
Upon reaching the upper side, the first transport line 12a temporarily stops.

(2) Next, as shown in FIG.
Pallets 1 and 2 on two-way conveyors 14 and 14a
It is moved forward on the two-way conveyors 14b and 14c by stepping forward. (3) Next, as shown in FIG. 2E, the pallet 1 on the third transport line 12c is advanced by one step, and the pallets 3, 4, 5, and 5 on the first transport line 12a are moved forward.
. Is advanced by one step to position the pallet 3 on the two-way conveyor 14a. At this time, the pallet 2 on the two-way conveyor 14c has stopped.

(4) Next, as shown in FIG.
The pallets 3, 4, 5,... On the first transport line 12a are moved forward by one step to position the pallets 3, 4 on the two-way conveyors 14, 14a, and the pallet 1 on the third transport line 12c is moved. Move forward one step. In addition, the pallet 2 on the two-way conveyor 14c is transferred onto the two-way conveyor 14b. (5) Next, as shown in FIG. 3A, the pallets 1 and 2 on the third transport line 12c are advanced by one step, and the pallets 3 and 4 on the two-way conveyors 14 and 14a.
Is moved onto the two-way conveyors 14b and 14c. At this time, the pallets 5 and 6 on the first transport line 12a have stopped. An empty portion for one step is formed between the pallets 1 and 2 on the third transport line 12c.

(6) Next, as shown in FIG.
The pallets 5, 2, 7,... On the first transport line 12a are advanced by one step while the pallets 5, 2, 7,... On the first transport line 12a are advanced by one step. On top. At this time, the pallet 4 is stopped on the two-way conveyor 14c. The pallets 2 and 3 are continuously transferred to the transfer line
c.

(7) Next, as shown in FIG. 3C, the pallets 1, 2, and 3 on the third transport line 12c are advanced by one step, and the pallets 5 on the first transport line 12a are moved forward. , 6, 7, ... are moved forward by one step to position the pallets 5, 6 on the two-way conveyors 14, 14a. Further, the pallet 4 is moved onto the two-way conveyor 14b. Hereinafter, similarly, the pallet which has passed the corner portion is continuously transported on the transport line 12c with the empty portion for one step forward and backward separated by the empty portion. In addition, the pallet is conveyed according to the above also at the junction of the receiving stations 18a and 18b and the branching part of the shipping stations 19a and 19b.

In the conventional conveyor, each pallet after the corner portion is conveyed across the empty portion of one pallet (alternately, the pallets and empty portions appear alternately). The transfer density was one half of the transfer conveyor. On the other hand, in the present embodiment, the pallet past the corner is the pallet 1
Since the two pallets are continuously fed before and after the empty portion for the number of pallets, the transport density of the pallets becomes two-thirds that of the transport conveyor. Therefore, according to the present embodiment, if the transport capacity of the conventional transport conveyor is 1,
(2/3) / (1/2) = 4/3 ≒ 1.33 times,
Since the transfer capacity can be increased by 30% or more, the work efficiency can be greatly improved.

In the above description, the case where the pallet is temporarily stopped several times is described. However, by slightly changing the drive timing of the first to fourth transport lines 12a to 12d and the two-way conveyor 14c, etc. The pallets can be transported almost continuously, which can further enhance the work efficiency. Also, conveyor 1
2 shows a case where the two-way conveyor 14c is attached to all of the corners, the merging portion of the receiving stations 18a and 18b, and the branching portion of the shipping stations 19a and 19b, but only a part of the two-way conveyors is provided. 14
c may be added.

[Embodiment 2] FIG. 4 is an explanatory view showing an example in which a transport conveyor according to Embodiment 2 of the present invention is used in an automatic warehouse system. The same parts as those in the first embodiment are denoted by the same reference numerals, and a part of the description will be omitted. In the above-described first embodiment, the case where the two-way conveyor 14c is provided inside the corner portion of the transport conveyor 12 is shown. In the present embodiment, the two-way conveyor 14c is provided outside the corner portion. It is.
The configurations of the receiving stations 18a, 18b and the shipping stations 19a, 19b are the same as in the first embodiment.

That is, a two-way conveyor 14a is provided downstream or upstream of the two-way conveyor 14 provided at each corner of the conveyor 12 and connected to the two-way conveyor 14 outside the corner to connect to the two-way conveyor 14. 14b, and further, by providing a two-way conveyor 14c at the corner formed by the two-way conveyors 14a and 14b, the four two-way conveyors 14, 14a, 14b, and 14c are formed in the corners. It is arranged in.

The pallet transfer operation at the corner in this embodiment is almost the same as that of the first embodiment, but the pallet transfer order is changed on the third transfer line 12c past the corner. You. In the above description, the case where the two-way conveyor 14c is attached outside all corners of the conveyor 12 has been described.
Bidirectional conveyor 14c only outside some corners
May be added.

[Embodiment 3] FIG. 5 is an explanatory diagram showing an example in which a transport conveyor according to Embodiment 3 of the present invention is used in an automatic warehouse system. The same parts as those in the first embodiment are denoted by the same reference numerals, and a part of the description will be omitted.

In the present embodiment, the third and fourth connecting lines connect both ends of the first and second transfer lines 12a and 12b.
Are provided on an extension line of the incoming conveyor 15 and the outgoing conveyor 16, and the two-way conveyor 14 at the corner formed by the first transport line 12 a and the third and fourth transport lines 12 c and 12 d is provided. The two-way conveyor 14a and 14b are provided on the upstream side and the downstream side of the two-way conveyor 14, respectively, so as to function as a two-way conveyor at a branching part of the incoming conveyor 15 and a two-way conveyor at a merging part of the outgoing conveyor 16. Conveyor 1
By attaching a two-way conveyor 14c inside the corner formed by the four-way conveyors 14a, 14c, and 14b, two two-way conveyors 14a, 14c, 14
b and 14c are respectively arranged in the shape of a day (in this case, the shape of a horizontal day is shown).

Further, two-way conveyors 14a and 14b are provided on the upstream and downstream sides of the two-way conveyor 14 at the corner formed by the second transfer line 12b and the third and fourth transfer lines 12c and 12d, respectively. The two-way conveyor 14a also serves as the two-way conveyor at the merging section of the receiving station 18a, and the two-way conveyor 14b serves as the two-way conveyor at the branching section of the shipping station 19a. Then, the two-way conveyor 1 provided immediately before the junction of the two-way conveyor 14 at the corner and the receiving station 18a.
4d, and outside the corner formed by the two-way conveyor 14 at the corner and the two-way conveyor 14d provided immediately after the branch of the shipping station 19a.
The two two-way conveyors 14 and 14c are arranged in the corners in the shape of the sun, respectively. The receiving station 18b and the shipping station 19b have the same configurations as those of the first embodiment.

The operation and effect of transferring the pallets at the corners of the transfer conveyor in this embodiment are almost the same as those in the first and second embodiments, but the third and fourth transfer lines 12c and 12d are stored. The first and second transport lines 12a and 12b can be shortened because they are provided on an extension of the conveyor 15 and the unloading conveyor 16. In this embodiment, the receiving conveyor 1 is also used.
The third or fourth transport lines 12c and 12d may be provided on an extension of only one of the conveyor 5 and the delivery conveyor 16.

[Fourth Embodiment] FIG. 6 is an illustration of a transport conveyor according to a fourth embodiment of the present invention. In the present embodiment, one of the third and fourth transfer lines 12c and 12d connecting both ends of the first and second transfer lines 12a and 12b constituting the transfer conveyor 12 (for example, 12c) to the third transfer line 12 of the first embodiment.
c, and the other fourth transport line 12d is
For example, two sets of one-way conveyors are arranged side by side.

That is, two-way conveyors 14a and 14b are provided on the upstream and downstream sides of the two-way conveyor 14 at both corners formed by the first, second and third transfer lines 12a, 12b and 12c, respectively. A two-way conveyor 14c is attached inside the corner. On the other hand, two-way conveyors 14a and 14b are provided on the upstream and downstream sides of the two-way conveyor 14 at the corners formed by the second, fourth, and first transfer lines 12b, 12d, and 12a. The first and second pairs of one-way conveyors 13a and 13b form a fourth transport line 12d by connecting the first and second sets of one-way conveyors 13a and 13b.

In this embodiment, the first, second, and third
The transport operation of the pallets at the corners formed by the transport lines 12a, 12b, and 12c is the same as that in the first embodiment, and a description thereof will be omitted. The second, fourth, and first transport lines 12b will be described below. , 12d and 12a will be described with reference to FIGS. 7 and 8. FIG. (1) The pallets 1, 2, 3,... Transported by the second transport line 12b are, as shown in FIG. 7 (a), the pallets 1 on the two-way conveyor 14 and the pallets 2
Are located on the two-way conveyor 14a.

(2) Next, as shown in FIG.
The pallets 1 and 2 move forward one step at the same time, and in parallel, the one-way conveyors 13a,
13b. At this time, the subsequent pallet 3,
4, 5, ... are stopped at that position. (3) Next, as shown in FIG. 7C, the pallets 1 and 2 on the fourth transport line 12d advance one step, and the pallets 3, 4, 5, and 5 on the second transport line 12b.
Move forward by one step, and the pallet 3 is positioned on the two-way conveyor 14a.

(4) Subsequently, as shown in FIG.
The pallets 3, 4, 5,... On the second transport line 12b advance one step while the pallets 1, 2, on the fourth transport line 12d advance one step.
Are located on the two-way conveyors 4, 14a. (5) Then, as shown in FIG. 7 (e), the pallets 1 and 2 on the fourth transport line 12d advance one step, and the two-way conveyors 14 and 14b of the first transport line 12a.
And the pallets 3 and 4 on the second transport line 12b are also translated by one step,
Move up to d. At this time, the pallets 5, 6, 7,... On the second transport line 12b are stopped at that position.

(6) Next, as shown in FIG.
Pallets 2 and 1 on the first transport line 12a are simultaneously 1
Step forward, the pallet 1 is moved to the two-way conveyor 14b.
Located on top. The pallets 3 and 4 on the fourth transport line 12d are simultaneously translated by one step, and the pallets 5, 6, 7,... On the second transport line 12b are also advanced by one step, and the pallet 5 is moved on the two-way conveyor. 14a. (7) Next, as shown in FIG. 8A, the pallets 2 and 1 on the first transport line 12a advance one step simultaneously, and the pallets 3 and 4 on the fourth transport line 12d also move one step. Translate Also, the pallets 5, 6, 7,... On the second transport line 12b advance one step, and the pallets 5, 6 are positioned on the two-way conveyors 14, 14a.

(8) Next, as shown in FIG.
The pallets 2 and 1 on the first transport line 12a advance one step, and the pallets 3 and 4 on the fourth transport line 12d also advance one step and the two-way conveyors 14 and 14 on the first transport line 12a, respectively. 14b. Further, the pallets 5, 6 on the second transfer line 12b
Moves forward one step and moves onto the fourth transport line 14d. At this time, the subsequent pallets 7, 8, 9, ... are stopped at that position.

(9) Next, as shown in FIG. 8 (c), the pallets 2, 1 and 4, 3 on the first transport line 12a advance one step at a time, respectively, and the pallet 3 moves on the two-way conveyor 14b. Located on top. In addition, pallets 2 and 1
And pallets 4 and 3 are conveyed continuously, respectively, and an empty portion for one pallet is formed between the pallets 2 and 1 in the former stage and the pallets 4 and 3 in the latter stage. The pallets 5, 6 on the fourth transport line 12d are translated by one step,
Are also advanced by one step, and the pallet 7 is located on the two-way conveyor 14a. (10) In the same manner, two pallets are continuously conveyed on the conveyance line 12a with an empty portion for one pallet separated.

As described above, in the present embodiment, the corner portion on one side of the loop-shaped transport conveyor is configured in the same manner as the corner portion of the first embodiment, and the transport line on the other side of the corner portion is formed by two. Since the sets of one-way conveyors are arranged side by side, not only the same effects as in the first embodiment can be obtained, but also the structure can be reduced, and the number of expensive two-way conveyors can be reduced, so that the installation cost can be reduced. be able to.

[Fifth Embodiment] FIG. 9 is an explanatory view of a transport conveyor according to a fifth embodiment of the present invention. In the present embodiment, the third transfer line 12c at the corner formed by the first, second, and third transfer lines 12a, 12b, and 12c in the fourth embodiment has the same structure as the other transfer line 12d. The one-way conveyors 13a and 13b are arranged side by side. The transport operation and effects in the present embodiment are almost the same as those in the fourth embodiment, but since the third and fourth transport lines 12c and 12d are constituted by the one-way conveyors 13a and 13b, the two-way conveyor is provided. Can be further reduced, and the installation cost can be further reduced.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and may be implemented by appropriately combining the above embodiments. In the above description, the case where the present invention is applied to a loop-shaped conveyor is shown. However, the present invention can also be applied to a U-shaped, L-shaped, or T-shaped conveyor.

[0045]

According to the conveyor of the present invention, four bidirectional conveyors are arranged in a cross in all or a part of a corner portion, a merging portion and a branch portion. Transfer density increases, the bolt neck at corners and the like is eliminated, and the transfer capacity can be increased.
Thereby, work efficiency can be improved. In addition, since the transportation order of articles such as pallets and packing materials can be changed in the corners and the like, the degree of freedom of the loading and unloading work is increased, and the work efficiency can be improved.

In the above conveyor, 4
In place of the two bidirectional conveyors, two bidirectional conveyors are arranged in the shape of a star at all or a part of the corner, the merging part, and the branch part or in the vicinity thereof, so that the same effects as above can be obtained. Can be.

Further, the transport conveyor according to the present invention comprises:
The above-described effects are obtained because two or one sets of one-way conveyors are arranged side by side, and / or one or both of the transfer lines connecting both ends of the opposed first and second transfer lines constituting the transfer conveyor. In addition, the number of two-way conveyors can be reduced, so that equipment costs can be reduced.

The automatic warehouse system according to the present invention comprises:
Since any one of the above-mentioned conveyors is used for the conveyor, the same effects as above can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example in which a transport conveyor according to Embodiment 1 of the present invention is used in an automatic warehouse system.

FIG. 2 is an explanatory diagram of a pallet conveying operation at a corner portion in FIG. 1;

FIG. 3 is an explanatory diagram of a pallet conveying operation at a corner portion in FIG. 1;

FIG. 4 is an explanatory diagram showing an example in which a transport conveyor according to Embodiment 2 of the present invention is used in an automatic warehouse system.

FIG. 5 is an explanatory diagram showing an example in which a transport conveyor according to Embodiment 3 of the present invention is used in an automatic warehouse system.

FIG. 6 is an explanatory diagram of a transport conveyor according to a fourth embodiment of the present invention.

FIG. 7 is an explanatory diagram of a pallet transfer operation at a corner portion in FIG. 6;

FIG. 8 is an explanatory diagram of a pallet conveying operation at a corner portion in FIG. 6;

FIG. 9 is an explanatory diagram of a transport conveyor according to a fifth embodiment of the present invention.

FIG. 10 is an explanatory diagram of an example of a conventional automatic warehouse system.

11 is an explanatory diagram of a pallet transfer operation at a corner of the transfer conveyor of FIG. 10;

12 is an explanatory diagram of a pallet transfer operation at a corner of the transfer conveyor of FIG. 10;

[Explanation of symbols]

Pallets 10 Storage areas 11 Storage shelves 12 Conveyors 12a, 12b, 12c, 12d First to fourth transfer lines 13, 13a, 13b Unidirectional conveyors 14, 14a, 14b, 14c, 14d Two Directional Conveyor 15 Receiving Conveyor 16 Outgoing Conveyor 18 Receiving Station 19 Shipping Station

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoichi Yoshinaga 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Japan Nippon Kokan Co., Ltd. (72) Inventor Shinichiro Eto 1-2-1-2 Marunouchi, Chiyoda-ku, Tokyo Japan Inside Honko Co., Ltd. (72) Inventor Hiroshi Ishikawa 1-2-2 Marunouchi, Chiyoda-ku, Tokyo F-term in Honkokan Co., Ltd. 3F022 AA15 EE02 LL31 MM01 MM02 MM11 3F070 AA06 AA18 DA06 EA21 EA24 FA06

Claims (4)

[Claims] 1. A transport conveyor having a one-way conveyor and a two-way conveyor for transporting articles such as pallets and packages, wherein all or part of corners, branches and junctions of the transport conveyor have A transport conveyor characterized in that two bidirectional conveyors are arranged in a cross-shaped manner. 2. Two or more two-way conveyors are arranged in the shape of a sun instead of four two-way conveyors at all or a part of a corner portion, a branch portion, and a merging portion of a transport conveyor or in the vicinity thereof. The transport conveyor according to claim 1, wherein: 3. A transport conveyor for transporting articles such as pallets and packages, wherein a third and a fourth transport line connecting both ends of opposed first and second transport lines constituting the transport conveyor are provided. A transport conveyor comprising two or one set of one-way conveyors arranged side by side, either or both. 4. An automatic warehouse system comprising an automatic warehouse and a transport conveyor, wherein the transport conveyor according to claim 1, 2, or 3 is used as the transport conveyor.