NL2016445B1

NL2016445B1 - Article accumulating device.

Info

Publication number: NL2016445B1
Application number: NL2016445A
Authority: NL
Inventors: Iwasa Takuya; Watanabe Kousuke; Komatsu Toshiyuki
Original assignee: Ishida Seisakusho
Priority date: 2015-03-18
Filing date: 2016-03-17
Publication date: 2017-03-06
Also published as: GB2536805B; GB2536805A; GB201603802D0; NL2016445A; JP2016175708A

Abstract

Provided is an article accumulating device for transferring articles from a delivery conveyor for delivering articles to a movable article accumulation section to accumulate them thereon with a plurality of robots, the article accumulating device being capable of preventing articles from being left behind on the delivery conveyor and therefore being high reliability. An article accumulating device is provided with: a delivery conveyor for delivering articles; an accumulation conveyor for accumulating articles as an article group, the accumulation conveyor moving in the same direction as the transport direction of the delivery conveyor; first and second robots for transferring the articles from the delivery conveyor to the accumulation conveyor; and a control unit for controlling both transfer robots. The second robot takes the articles from the delivery conveyor at the downstream side relative to the position where the first transfer robot takes the articles, and transfers the articles to the accumulation conveyor at the downstream side relative to the position to which the first transfer robot transfers the articles. The control unit controls both transfer robots so that the ratio of the number of the articles transferred by the second transfer robot in an initial article group at the start of accumulation is greater than the ratio of the number of the articles transferred by the second transfer robot in the article group during ordinary operation.

Description

DESCRIPTION

ARTICLE ACCUMULATING DEVICE

TECHNICAL FIELD

The present invention relates to an article accumulating device, more specifically, to an article accumulating device for transferring articles from an article-delivering delivery conveyor to a movable article accumulation section with a plurality of robots, and accumulating a predetermined number of articles as a single article group.

BACKGROUND ART

An article accumulating device for transferring articles from an article-delivering delivery conveyor to a movable article accumulation section with a robot and accumulating a predetermined number of articles as a single article group is known.

For example, patent literature 1 (Japanese Laid-open Patent Application No. 2012-188231) discloses a device for transferring articles delivered by a delivery conveyor to an accumulation conveyor with a robot and accumulating the articles on an accumulation conveyor.

In such an article accumulating device, depending on the required processing capacity, there are cases in which a plurality of robots are arranged along the transport direction of the articles and the plurality of robots work in cooperation to accumulate the articles of each article group.

SUMMARY OF THE INVENTION

Technical Problem

When articles delivered by the delivery conveyor are transferred and accumulated on the article accumulating section using a plurality of robots, there are cases in which articles are left behind on the delivery conveyor at the start of accumulation, even though operation is being carried out in the same manner as usual. A state in which articles are left behind on the delivery conveyor means a state in which there is an article, which is not been transferred to the article accumulation section by any of the robots, on the delivery conveyor. Specifically, a state may arise in which, when the most downstream robot in the transport direction of the articles attempts to transfer the articles on the delivery conveyor, the region for transferring the articles in the article accumulation section has not arrived at the position to which the most downstream robot can transfer the article.

Accordingly, the article left behind on the delivery conveyor is liable to be discarded and wasted. Even when the article left behind on the delivery conveyor is to be reused, a mechanism for returning the article to the upstream side and/or work for returning the article to the upstream side is required, and this is liable to lead to increased device cost and/or an increased amount of work.

An object of the present invention is to provide an article accumulating device for transferring an article from an article-delivering delivery conveyor to a movable article accumulation section with a plurality of robots and accumulating a predetermined number of articles as a single article group, the article accumulating device being capable of preventing articles on a delivery conveyor from being left behind at the start of accumulation and therefore being highly reliable.

Solution to Problem

An article accumulating device according to a first aspect of the present invention is provided with a delivery conveyor, a movable accumulation section, a first robot, a second robot, and a control unit. The delivery conveyor is configured to deliver articles. The movable accumulation section is configured to accumulate a predetermined number of articles as a single article group. The movable accumulation section is configured to move in a second direction being the same as a first direction, which is a transport direction of the delivery conveyor. The first robot is configured to take the articles from a first pickup area of the delivery conveyor and transfer the articles to a first accumulation area of the movable accumulation section. The second robot is configured to take the articles from a second pickup area of the delivery conveyor and transfer the articles to a second accumulation area of the movable accumulation section. The second pickup area is positioned at the downstream side relative to the first pickup area in the first direction. The second accumulation area is positioned at the downstream side relative to the first accumulation area in the second direction. The control unit is configured to control the first robot and the second robot so that the articles are accumulated as the article group on the movable accumulation section. The control unit is configured to control the first robot and the second robot so that the ratio of the number of the articles transferred by the second robot in an initial article group at the start of accumulation of the articles is greater than the ratio of the number of the articles transferred by the second robot in article group during ordinary operation.

With the article accumulating device according to the first aspect of the present invention, the ratio of articles transferred to the movable accumulation section by the downstream-side second robot in the initial article group at the start of article accumulation is greater than the ratio of articles transferred to the movable accumulation section by the second robot in the article groups during ordinary operation. Accordingly, it is possible to prevent a situation in which the region for transferring the article has not arrived at the position to which the second robot can transfer the article when the second robot is to transfer articles from the delivery conveyor at the start of accumulation.

An article accumulating device according to a second aspect of the present invention is the article accumulating device according to the first aspect of the present invention, wherein the control unit is configured to control the first robot so that at least two of the articles delivered by the delivery conveyor consecutively pass through the first pickup area without being taken by the first robot before accumulation of the initial article group has been finished after the start of accumulation.

With the article accumulating device according to the second aspect of the present invention, at least two of the articles delivered by the delivery conveyor consecutively pass through the pickup range of the first robot without being transferred by the first robot before accumulation of the initial article group has been finished. It is therefore possible to increase the ratio of articles transferred to the movable accumulation section by the downstream-side second robot in the initial article group at the start of article accumulation.

An article accumulating device according to a third aspect of the present invention is the article accumulating device according to the first or second aspect of the present invention, wherein the control unit is configured to control the first robot and the second robot so that the ratio of the number of the articles transferred by the second robot in second and subsequent article groups after the start of accumulation is 50%.

With the article accumulating device according to the third aspect of the present invention, the ratio of the number of the articles transferred by the second robot in the second and subsequent article groups is 50%. In other words, each of the first robot and the second robot operates so as to accumulate the same number of articles. The first robot and the second robot can therefore be operated with good efficiency.

Advantageous Effects of Invention

With the article accumulating device according to the present invention, the ratio of articles transferred to the movable accumulation section by the downstream-side second robot in the initial article group at the start of article accumulation is greater than the ratio of articles transferred to the movable accumulation section by the second robot in the article groups during ordinary operation. Accordingly, it is possible to prevent a situation in which the region for transferring the article has not arrived at the position to which the second robot can transfer the article when the second robot is to transfer articles from the delivery conveyor at the start of accumulation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view of a box-packing system including the article accumulating device according to an embodiment of the present invention. FIG. 2 is a schematic plan view of the box-packing system in FIG. 1. FIG. 3 is a block diagram of the box-packing system in FIG. 1. FIG. 4 is an external perspective view of the first transfer robot included in the article accumulating device in FIG. 1. FIG. 5 is an external perspective view of the box-packing robot included in the boxpacking system in FIG. 1. FIG. 6 is a drawing illustrating the operation for transferring articles carried out with the first transfer robot and the second transfer robot when the control unit controls the first transfer robot and the second first transfer robot in an ordinary distribution control mode from the start of accumulation. Plan views of the delivery conveyor and the accumulation conveyor are illustrated in chronological order. FIG. 7A is a drawing illustrating the operation for transferring articles carried out with the first transfer robot and the second transfer robot when the control unit controls the first transfer robot and the second first transfer robot in an initial special distribution control mode for only the initial article group at the start of accumulation, and controls the first transfer robot and the second transfer robot in the ordinary distribution control mode for the second and subsequent article groups after the start of accumulation. Plan views of the delivery conveyor and the accumulation conveyor are illustrated in chronological order. FIG. 7B is a continuation of FIG. 7A. FIG. 7B is a drawing illustrating the operation for transferring articles carried out with the first transfer robot and the second transfer robot when the control unit controls the first transfer robot and the second first transfer robot in an initial special distribution control mode for only the initial article group at the start of accumulation, and controls the first transfer robot and the second transfer robot in the ordinary distribution control mode for the second and subsequent article groups after the start of accumulation. Plan views of the delivery conveyor and the accumulation conveyor are illustrated in chronological order. FIG. 8A is a drawing for modification A illustrating the operation for transferring articles carried out with the first transfer robot and the second transfer robot when the control unit controls the first transfer robot and the second first transfer robot in an initial special distribution control mode according to another example for only the initial article group at the start of accumulation, and controls the first transfer robot and the second transfer robot in the ordinary distribution control mode for the second and subsequent article groups after the start of accumulation. Plan views of the delivery conveyor and the accumulation conveyor are illustrated in chronological order. FIG. 8B is a continuation of FIG. 8A. FIG 8B is a drawing for modification A illustrating the operation for transferring articles carried out with the first transfer robot and the second transfer robot when the control unit controls the first transfer robot and the second first transfer robot in an initial special distribution control mode according to another example for only the initial article group at the start of accumulation, and controls the first transfer robot and the second transfer robot in the ordinary distribution control mode for the second and subsequent article groups after the start of accumulation. Plan views of the delivery conveyor and the accumulation conveyor are illustrated in chronological order.

DESCRIPTION OF EMBODIMENTS (1) Overall configuration FIG. 1 is a schematic side view of a box-packing system 1 including an article accumulating device 100 according to an embodiment of the present invention. FIG. 2 is a schematic plan view of the box-packing system 1. In FIG 2, a later-described first transfer robot 30 and second transfer robot 40 of the article accumulating device 100, and boxpacking robot 200 are indicated by two-dot chain lines. FIG. 3 is a block diagram of the box-packing system 1.

The box-packing system 1 mainly includes the article accumulating device 100, the box-packing robot 200, and a box transport conveyor 300 (see FIGS. 1 and 2). The article accumulating device 100 is mainly provided with a delivery conveyor 10, an accumulation conveyor 20, a first transfer robot 30, a second transfer robot 40, and a control unit 50 (see FIGS. 1 to 3). In the present embodiment, the control unit 50 controls not only the operation of the article accumulating device 100, but also controls the overall operation of the box-packing system 1, which includes the box-packing robot 200 and box transport conveyor 300. However, the control unit 50 is not required to be a unit for controlling the overall operation of the box-packing system 1. The control unit 50 may control only the operation of the article accumulating device 100 and another control unit for controlling the operation of the box-packing robot 200 and the box transport conveyor 300 may be separately provided.

The box-packing system 1 is generally configured in the following manner.

The article accumulating device 100 is a device for transferring articles P from the delivery conveyor 10 to the accumulation conveyor 20 with the first transfer robot 30 and the second transfer robot 40, and accumulating a predetermined number of articles P as a single article group G on the accumulation conveyor 20 (see FIG. 2). The articles P are the objects to be accumulated transported by the delivery conveyor 10. The articles P are, e.g., bags filled with snack food, but are not limited thereto.

The article group G accumulated by the article accumulating device 100 (article group G on the accumulation conveyor 20) is packed in a box B placed on the box transport conveyor 300 by the box-packing robot 200. The box B in which the article group G is packed is carried to a next process (e.g., a process for closing the top lid of the box B) by the box transport conveyor 300. (2) Detailed configuration

The box-packing system 1 is described in detail below. (2-1) Article-accumulating device

The article accumulating device 100 is provided with a delivery conveyor 10, an accumulation conveyor 20, a first transfer robot 30, a second transfer robot 40, and a control unit 50. In the present embodiment, the control unit 50 also functions as a control unit for controlling the overall operation of the box-packing system 1. The control unit 50 will therefore be described later separately from the description of the article accumulating device 100. (2-1-1) Delivery conveyor

The delivery conveyor 10 is a mechanism for delivering articles P. The articles P are objects to be packed in a box by the box-packing system 1. In other words, the articles P are objects accumulated by the article accumulating device 100. The delivery conveyor 10 transports the articles P from an upstream-side process to an accumulation location (a location where the first transfer robot 30 and the second transfer robot accumulate articles P). The delivery conveyor 10 transports the articles P in a transport direction (a first direction D1) indicated by an arrow in FIG. 2. The articles P are placed on the delivery conveyor 10 at roughly equal intervals on the upstream side. The delivery conveyor 10 transports the articles P placed at roughly equal intervals.

The delivery conveyor 10 is specifically a belt conveyor. However, the type of delivery conveyor 10 is not limited to a belt conveyor and may be another type of transport mechanism.

The delivery conveyor 10 is arranged above the later-described box transport conveyor 300 (see FIG. 1). The delivery conveyor 10 is arranged at the same height as the accumulation conveyor 20 (so that the transport surface of the delivery conveyor 10 and the transport surface of the accumulation conveyor 20 are at the same height). However, no limitation is imposed thereby; the delivery conveyor 10 and the accumulation conveyor 20 may be arranged at different heights. (2-1 -2) Accumulation conveyor

The accumulation conveyor 20 is an example of a movable accumulation section. A predetermined number of articles P are accumulated as a single article group G on the accumulation conveyor 20 by the first transfer robot 30 and the second transfer robot 40. The accumulation conveyor 20 transports the articles P transferred from the delivery conveyor 10 by the later-described first transfer robot 30 and second transfer robot 40. In other words, the accumulation conveyor 20 transports the article group G accumulated by the first transfer robot 30 and the second transfer robot 40.

The accumulation conveyor 20 is specifically a belt conveyor. However, the type of accumulation conveyor 20 is not limited to a belt conveyor and may be another type of transport mechanism.

The transport surface of the accumulation conveyor 20 is arranged on the same imaginary plane as the transport surface of the delivery conveyor 10. In other words, the transport surface of the accumulation conveyor 20 is arranged at the same height as the transport surface of the delivery conveyor 10.

The accumulation conveyor 20 transports articles P (accumulated articles P) in a second direction D2, the same direction as the first direction D1. The first direction D1 is the transport direction of the delivery conveyor 10. In other words, the accumulation conveyor 20 moves in the second direction D2, which is the same direction as the first direction D1, the first direction being the transport direction of the delivery conveyor 10 (see FIG. 2). The accumulation conveyor 20 and the delivery conveyor 10 are arranged so as to be adjacent and lined up in the direction orthogonal to the first direction D1 and second direction D2 (see FIG. 2). (2-1-3) First transfer robot and second transfer robot

The first transfer robot 30 is an example of the first robot. The second transfer robot 40 is an example of the second robot.

The first transfer robot 30 and the second transfer robot 40 cooperatively transfer a predetermined number of articles P onto the accumulation conveyor 20 so as to be organized in a predetermined manner and accumulate them as a single article group G. In a specific example, the first transfer robot 30 and second transfer robot 40 transfer four articles P onto the accumulation conveyor 20 so that two articles P are lined up in the second direction D2, which is the transport direction of the accumulation conveyor 20, and two articles P are lined up in the direction orthogonal to the second direction D2 as viewed from above, and accumulate the articles as a single article group Q

The first transfer robot 30 and the second transfer robot 40 are arranged above the delivery conveyor 10 and the accumulation conveyor 20. The second transfer robot 40 is arranged at the downstream side relative to the first transfer robot 30 in the first direction D1, which is the transport direction of the delivery conveyor 10 (see FIGS. 1 and 2).

The first transfer robot 30 and the second transfer robot 40 are herein parallel link robots. However, the type of first transfer robot 30 and second transfer robot 40 is not limited thereto.

The detailed configuration of the first transfer robot 30 is described below. The second transfer robot 40 has the same configuration as the first transfer robot 30 and a description of the second transfer robot 40 is therefore omitted.

The first transfer robot 30 mainly has a head 31, a plurality of vacuum-chucking pads 32 affixed to the head 31, three arms 33, a base 34, and a suction tube 35 (see FIG. 4). The lower end part of the three arms 33 is linked to the head 31. The three arms 33 are driven by a plurality of servomotors (not shown) affixed to the base 34. The arms 33 linked to the head 31 are driven by the servomotors, whereby the head 31 is moved three-dimensionally in a movable range. One end of the suction tube 35 is connected to the vacuum-chucking pads 32 and the other end is connected to a vacuum pump and/or a vacuum blower (not shown).

The first transfer robot 30 generally operates in the following manner when the articles P are transferred from the delivery conveyor 10 to the accumulation conveyor 20.

First, when the first transfer robot 30 is to take the articles P from the delivery conveyor 10, the arms 33 are driven by the plurality of servomotors (not shown) affixed to the base 34 and the head 31 is moved so that the vacuum-chucking pads 32 affixed to the head 31 are pressed against the article P. In this state, a vacuum pump or the like connected to the suction tube 35 is driven, whereby the article P is gripped by the vacuum-chucking pads 32.

Next, when the first transfer robot 30 is to transfer the article P onto the accumulation conveyor 20, the arms 33 are driven in a state that the vacuum-chucking pads 32 grips the article P and the head 31 is moved to a predetermined position over the accumulation conveyor 20. The predetermined position over the accumulation conveyor 20 to which the head 31 being moved is set to a suitable position for organizing and accumulating a predetermined number of articles P as a single article group G on the accumulation conveyor 20. The sucking and gripping state of the vacuum-chucking pads 32 is released in a state that the head 31 is moved to the predetermined position over the accumulation conveyor 20, whereby the articles P are transferred onto the accumulation conveyor 20.

Because the movable region of the head 31 is fixed as described above, regions on the delivery conveyor 10 from which the first transfer robot 30 and second transfer robot 40 respectively can take the articles P are limited. In addition, regions on the accumulation conveyor 20 to which the first transfer robot 30 and second transfer robot 40 respectively can transfer the articles P are limited.

The first transfer robot 30 takes the articles P from a first pickup area A1 of the delivery conveyor 10 and transfers the articles to a first accumulation area C1 of the accumulation conveyor 20 (see the regions enclosed by a broken line in FIG. 2). Meanwhile, the second transfer robot 40 takes the articles P from a second pickup area A2 of the delivery conveyor 10 and transfers the articles to a second accumulation area C2 of the accumulation conveyor 20 (see the regions enclosed by a broken line in FIG. 2). The second pickup area A2 is positioned at the downstream side relative to the first pickup area A1 in the first direction D1, which is the transport direction of the delivery conveyor 10. The second accumulation area C2 is positioned at the downstream side relative to the first accumulation area C1 in the second direction D2, which is the transport direction of the accumulation conveyor 20. (2-2) Box-packing robot

The box-packing robot 200 is arranged above the accumulation conveyor 20 and the box transport conveyor 300. The box-packing robot 200 is arranged at the downstream side relative to the second transfer robot 40 in the second direction D2, which is the transport direction of the accumulation conveyor 20 (see FIG. 2).

The box-packing robot 200 grips the article group G accumulated on the accumulation conveyor 20, i.e., a predetermined number of articles P in a single operation, and packs the articles inside a box B on the box transport conveyor 300.

Herein, the box-packing robot 200 is a parallel moving robot. However, the type of box-packing robot 200 is not limited thereto.

The box-packing robot 200 mainly has a head 210, a vacuum-chucking pad 220 affixed to the head 210, a mast 230, a vertical movement mechanism 240, a horizontal movement mechanism 250, and a suction tube 260 (see FIG. 5). The lower end part of the mast 230 is linked to the head 210. The mast 230 is driven in the vertical direction by the vertical movement mechanism 240. The mast 230 is driven in the horizontal direction (specifically, the direction orthogonal to the second direction D2, which is the transport direction of the accumulation conveyor 20, as viewed from above) by the horizontal movement mechanism 250. The mast 230 linked to the head 210 is driven by the vertical movement mechanism 240 and the horizontal movement mechanism 250, and the head 210 is thereby driven in the vertical direction and the horizontal direction orthogonal to the second direction D2. One end of the suction tube 260 is connected to the vacuum-chucking pad 220 and the other end is connected to a vacuum pump and/or a vacuum blower (not shown).

The box-packing robot 200 generally operates in the following manner when the article group G is packed in the box B.

First, when the box-packing robot 200 is to take the article group G from the accumulation conveyor 20, the mast 230 is driven by the vertical movement mechanism 240 and the horizontal movement mechanism 250, and the head 210 is moved so that the vacuum-chucking pad 220 affixed to the head 210 is pressed against all of the articles P constituting the article group G. In this state, a vacuum pump or the like connected to the suction tube 260 is driven, whereby the article group G (a plurality of articles P) is gripped by the vacuum-chucking pad 220.

Next, when the box-packing robot 200 is to pack the articles P into the box B on the box transport conveyor 300, the mast 230 is driven in a state that the vacuum-chucking pad 220 grips the articles P and the head 210 is moved above or into the interior of the box B on the box transport conveyor 300. The sucking and gripping state of the vacuum-chucking pad 220 is released in a state that the head 210 arranged above or inside the box B, whereby the article group G is packed (accommodated) inside the box B.

Herein, the box-packing robot 200 packs the article group G once in each box B, but no limitation is imposed thereby. The box-packing robot 200 may be configured to pack the article group G a predetermined number of times in each box B. (2-3) Box transport conveyor

The box transport conveyor 300 is a transport mechanism for receiving a supply of boxes B from a box-supplying mechanism (not shown) and transporting the boxes to a downstream-side process after the box-packing robot 200 has packed the articles P (article group G) in the boxes B. The box transport conveyor 300 is arranged below the accumulation conveyor 20 on which the articles P packed by the box-packing robot 200 are accumulated (see FIG. 1).

The box transport conveyor 300 is specifically a roller conveyor. However, the type of box transport conveyor 300 is not limited to a roller conveyor and may be another type of transport mechanism.

The box transport conveyor 300 transports the box B in a third direction D3, which is the same as the second direction D2, the transport direction of the accumulation conveyor 20. However, the box B transport direction on the box transport conveyor 300 is an example and no limitation is imposed thereby. The box B transport direction on the box transport conveyor 300 can be determined, as appropriate, by the layout or the like of the location where the box-packing system 1 is installed. (2-4) Control unit

The control unit 50 controls the operation of each constituent of the box-packing system 1 including the article accumulating device 100. In other words, the control unit 50 is an example of the control unit of the article accumulating device 100.

The control unit 50 is connected to each constituent of the box-packing system 1, e.g., the delivery conveyor 10, the accumulation conveyor 20, the first transfer robot 30, and the second transfer robot 40 of the article accumulating device 100, the box-packing robot 200, and the box transport conveyor 300. The control unit 50 is also connected to various sensors (e.g., a photoelectronic sensor or the like (not shown) for ascertaining the position of the articles P on the delivery conveyor 10).

The control unit 50 mainly has a CPU 51 and a memory 52 such as ROM, RAM or other (see FIG. 3). In the control unit 50, the CPU 51 executes a program stored in the memory 52 to thereby control each constituent of the box-packing system 1 including the article accumulating device 100.

Specifically, for example, the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 so that the articles P are accumulated as the article group G on the accumulation conveyor 20. More specifically, the control unit 50 controls the operation of the first transfer robot 30 and the second transfer robot 40 based on signals or the like from position detection means for ascertaining the position of the articles P on the delivery conveyor 10 so that the first transfer robot 30 and the second transfer robot 40 take the articles P from a predetermined position of the delivery conveyor 10 at a predetermined timing. The control unit 50 also controls the operation of the first transfer robot 30 and the second transfer robot 40 so that the first transfer robot 30 and the second transfer robot 40 transfer the articles P to a predetermined position of the accumulation conveyor 20 at a predetermined timing.

As modes for controlling the first transfer robot 30 and the second transfer robot 40, the control unit 50 has an initial special distribution control mode and an ordinary distribution control mode. The initial special distribution control mode is executed only when the initial article group G at the start of accumulation (hereinafter, the initial article group G at the start of accumulation will be referred to as the first article group G1) is accumulated. The ordinary distribution control mode is executed when the second and subsequent article groups G after the start of accumulation (hereinafter, the second and subsequent article groups G after the start of accumulation will be referred to as other article groups Go) are accumulated. As used herein, the expression “at the start of accumulation” means the point in time at which the stopped article accumulating device 100 starts its operation in a state that there is no articles P in process (partially accumulated article group G) on the accumulation conveyor 20 when the box-packing system 1 is started up or at other times.

In the ordinary distribution control mode, the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 so that the first transfer robot 30 and the second transfer robot 40 respectively transfer the articles P constituting the article group G to the accumulation conveyor 20 in equal numbers. In a specific example, in a case that when a single article group G is composed of four articles P, the first transfer robot 30 and the second transfer robot 40 respectively transfer two articles P per each single article group G, when the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 in the ordinary distribution control mode.

In other words, when the other article groups Go (the second and subsequent article groups G after the start of accumulation) are accumulated, the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 so that the ratio of the number of articles P transferred by the second transfer robot 40 in the other article groups Go is 50%.

Controlling the first transfer robot 30 and the second transfer robot 40 so that each of the robot transfers the same number of articles P for a single article group G allows that the both robots transfer the articles P to the accumulation conveyor 20 under the same processing load. Accordingly, in the ordinary distribution control mode, the efficiency of the first transfer robot 30 and the second transfer robot 40 can be kept high, since it is prevented that a situation in which a transfer robot under a low processing load waits for a transfer robot under a high processing load to be caused.

In the initial special distribution control mode executed when the first article group G1 is to be accumulated, the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 so that the ratio of the number of articles P transferred by the second transfer robot 40 in the first article group G1 is greater than the ratio (i.e., 50%) of the number of articles P transferred by the second transfer robot 40 in the article group G during ordinary operation (the other article groups Go during execution of the ordinary distribution control mode). Specifically, in the initial special distribution control mode, the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 so that the ratio of the number of articles P transferred by the second transfer robot 40 in the first article group G1 is 100%. In other words, in the initial special distribution control mode, the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 so that the articles P constituting the first article group G1 are transferred to the accumulation conveyor 20 only by the second transfer robot 40. The reason why the initial special distribution control mode is carried out when the first article group G1 is to be accumulated is described later.

The control unit 50 also controls the operation of the delivery conveyor 10 and the accumulation conveyor 20. Specifically, the control unit 50 controls the transport speed of the delivery conveyor 10 so that the first transfer robot 30 and the second transfer robot 40 are able to take the articles P from the delivery conveyor 10 at a predetermined position and at a predetermined timing. The control unit 50 also controls the transport speed of the accumulation conveyor 20 so that the first transfer robot 30 and the second transfer robot 40 are able to transfer the articles P to the accumulation conveyor 20 at a predetermined position and at a predetermined timing. Herein, the control unit 50 keeps the transport speed of the delivery conveyor 10 constant. However, no limitation is imposed thereby, and the control unit 50 may also vary the transport speed of the delivery conveyor 10.

The control unit 50 controls the box-packing robot 200 so that the box-packing robot 200 takes the article group G accumulated on the accumulation conveyor 20 from a predetermined position at predetermined timing and packs the article group G in the box B on the box transport conveyor 300. Also, the control unit 50 controls the box transport conveyor 300 so that the box B is transported in the third direction D3 after the article group G has been packed in the box B by the box-packing robot 200. (3) Operation for transferring articles with the first and second transfer robots

Described next is the operation for transferring articles P to the accumulation conveyor 20 with the first transfer robot 30 and the second transfer robot 40.

Here, the operation for transferring the articles P to the accumulation conveyor 20 with the first transfer robot 30 and the second transfer robot 40 will be described using an example in which four articles P are transferred and accumulated as a single article group G onto the accumulation conveyor 20 such that, as viewed from above, two articles P are lined up in the second direction D2, which is the transport direction of the accumulation conveyor 20, and two articles P are lined up in the direction orthogonal to the second direction D2. (3-1) Problems that occur when the first and second transfer robots are controlled only in the ordinary distribution control mode

Described first with reference to FIG. 6 is a problem that occurs when the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 only in the ordinary distribution control mode.

First, it will be described how to read FIG. 6. FIG. 6 chronologically illustrates the placement state of the articles P on the delivery conveyor 10 and the accumulation conveyor 20. In FIG 6, older (earlier) placement states are illustrated as it goes upward. In FIG. 6, older (earlier) placement states are illustrated with symbols T1, T2, T3, ... having smaller numerals, which is arranged at the left side of the delivery conveyor 10 and the accumulation conveyor 20. The symbols T1, T2, T3, ... represent the time.

In FIG. 6, the transport direction (first direction D1) of the delivery conveyor 10 and the transport direction (second direction D2) of the accumulation conveyor 20 are rightward. The vertically extending two-dot chain lines in FIG. 6 define the first pickup area A1 and the first accumulation area C1 of the first transfer robot 30 and the second pickup area A2 and the second accumulation area C2 of the second transfer robot 40. Specifically, the area between the two two-dot chain lines on the left side of the delivery conveyor 10 indicates the first pickup area A1. The area between two two-dot chain lines on the left side of the accumulation conveyor 20 indicates the first accumulation area C1. The area between the two two-dot chain lines on the right side of the delivery conveyor 10 indicates the second pickup area A2. The area between two two-dot chain lines on the right side of the accumulation conveyor 20 indicates the second accumulation area C2.

The regions R1, R2, R3, ... indicated by the broken lines on the accumulation conveyor 20 are regions in which the articles P are to be transferred in order to accumulate the article group G. In particular, region R1 indicates a region in which the articles P are to be transferred in order to accumulate the initial article group G (the first article group G1) at the start of accumulation. The regions R2, R3, ... indicate regions in which the articles P are to be transferred in order to accumulate the second and subsequent article groups (the other article groups Go) after the start of accumulation. Each of the four divided zones in the regions R1, R2, R3, ... indicate positions in which the articles P are to be transferred. Zones with hatching among the zones inside the regions R1, R2, R3, ... indicate that an article P has already been transferred by the first transfer robot 30 or the second transfer robot 40. Zones with hatching upward to the right among the zones inside the regions R1, R2, R3, ... indicate that an article P has been transferred by the first transfer robot 30. Zones with hatching downward to the right among the zones inside the regions R1, R2, R3, ... indicate that an article P has been transferred by the second transfer robot 40. The reference numerals for regions R2, R3, ... are partially omitted to make the drawing easier to view. A rectangle shown on the delivery conveyor 10 indicates an article P transported by the delivery conveyor 10. Here, the rectangle shown on the delivery conveyor 10 moves a single position of the rectangle on the downstream side in the transport direction (first direction D1) of the delivery conveyor 10 together with the passage of time (as time progresses T1, T2, ...). The symbol indicating the articles P are partially omitted to make the drawing easier to view. The rectangle shown by a solid line on the delivery conveyor 10 indicates that an article P represented by the rectangle is present on the delivery conveyor 10. On the other hand, the rectangle shown by a broken line on the delivery conveyor 10 indicates that an article P represented by the rectangle is no longer present on the delivery conveyor 10 (already transferred to the accumulation conveyor 20). The number notated inside the rectangle representing the article P indicates whether the article P should be transferred to the accumulation conveyor 20 by the first transfer robot 30 or the second transfer robot 40. The number "1" indicates that the article P is to be transferred to the accumulation conveyor 20 by the first transfer robot 30, and the number "2" indicates that the article P is to be transferred to the accumulation conveyor 20 by the second transfer robot 40.). The arrow extending from the article P on the delivery conveyor 10 indicates the movement of the article P from the delivery conveyor 10 to the accumulation conveyor 20 with the first transfer robot 30 or the second transfer robot 40.

The operation for transferring the articles P to the accumulation conveyor 20 with the first transfer robot 30 and the second transfer robot 40 will be described with reference to FIG. 6 for the case in which the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 only in the ordinary distribution control mode.

As shown in FIG. 6, when the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 only in the ordinary distribution control mode, the first transfer robot 30 and the second transfer robot 40 are controlled so as to take the articles P transported by the delivery conveyor 10 in alternating fashion, and to transfer the articles to the accumulation conveyor 20. Specifically, for example, the first article P transported by the delivery conveyor 10 is an article P to be transferred by the first transfer robot 30, and the second article P is an article P to be transferred to the accumulation conveyor 20 by the second transfer robot 40.

In FIG 6, the first transfer robot 30 operates so that the articles P, which is transported by the delivery conveyor 10 and is to be transferred by the first transfer robot 30, are transferred to the accumulation conveyor 20 in sequence from the downstream side in the transport direction (second direction D2) of the accumulation conveyor 20 on the far side in relation to the delivery conveyor 10 in the regions R1, R2, R3, ..., in the sequence of the regions having a smaller reference numeral value among the regions R1, R2, R3, ... on the accumulation conveyor 20. The second transfer robot 40 operates so that the articles P, which is transported by the delivery conveyor 10 and is to be transferred by the second transfer robot 40, are transferred to the accumulation conveyor 20 in sequence from the downstream side in the transport direction (second direction D2) of the accumulation conveyor 20 on the near side of the delivery conveyor 10 in the regions R1, R2, R3, ..., in the sequence of the regions having a smaller reference numeral value among the regions R1, R2, R3, ... on the accumulation conveyor 20.

When operating in this manner, there is an article P to be transferred by the second transfer robot 40 present in the second pickup area A2 of the delivery conveyor 10 at time T6 and time T7. However, at such time, the region R1 on the accumulation conveyor 20 has not yet arrived at the second accumulation area C2 where the second transfer robot 40 can transfer the article P. Accordingly, at time T7, the second transfer robot 40 allows the article P to be transferred to pass through the second pickup area A2 without being taken. As a result, the article P which is to be transferred by the second transfer robot 40 is discharged to the exterior of the delivery conveyor 10 (see time T10). The article P is wasted if the article P discharged to the exterior of the delivery conveyor 10 is discarded. When the article P discharged to the exterior of the delivery conveyor 10 is to be reused, a mechanism for returning the article P to the upstream side and/or work to return the article P to the upstream side is required, and therefore device cost is increased and/or the quantity of work is increased. (3-2) Transfer operation with the first and second transfer robots in a case that the first and second transfer robots are controlled in the initial special distribution control mode for the first article group

The operation for transferring an article P with the first transfer robot 30 and the second transfer robot 40 will be described with reference to FIGS. 7A and 7B for the case in which the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 in the initial special distribution control mode only for the initial article group G (the first article group G1) at the start of accumulation, and the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 in the ordinary distribution control mode for the second and subsequent article groups G (the other article groups Go) after the start of accumulation. FIGS. 7A and 7B have many corresponding features with FIG. 6 regarding how to read them, so only the points of difference will be described regarding how to read FIGS. 7A and 7B. At time T14 in FIG. 7B, the accumulated first article group G1 is no longer present on the accumulation conveyor 20. This shows that the box-packing robot 200 has packed the first article group G1 in the box B on the box transport conveyor 300 at time T13. Other descriptions regarding howto read FIGS. 7Aand 7B are omitted.

The operation of the first transfer robot 30 and the second transfer robot 40 shown in FIGS. 7A and 7B and the operation of the first transfer robot 30 and the second transfer robot 40 shown in FIG. 6 differ mainly in terms of the following points.

For a predetermined interval after accumulation has started, instead of taking the articles P in the sequence of transport on the delivery conveyor 10 with first transfer robot 30 and the second transfer robot 40 in alternative fashion and transferring onto the accumulation conveyor 20, the second transfer robot 40 transfers a greater number of articles P to the accumulation conveyor 20. Specifically, when the first to eighth articles in the transport sequence of the delivery conveyor 10 are viewed, the first, third, and sixth articles from the start are transferred to the accumulation conveyor 20 by the first transfer robot 30, and the second, fourth, fifth, seventh, and eighth articles from the start are transferred to the accumulation conveyor 20 by the second transfer robot 40 (see time T7). The ninth and later articles in the transport sequence of the delivery conveyor 10 are transferred to the accumulation conveyor 20 in alternating fashion by the first transfer robot 30 and the second transfer robot 40 (see times T8 to T15). In other words, the control unit 50 controls the first transfer robot 30 so that at least two of the articles P delivered by the delivery conveyor 10 consecutively pass through the first pickup area A1 without being taken by the first transfer robot 30 before the initial article group G (the first article group G1) is completely accumulated after the start of accumulation (prior to time T12).

All of the articles P are transferred by the second transfer robot 40 in the region R1 on the accumulation conveyor 20 (see time T12), as shown in FIGS. 7Aand 7B. In other words, the ratio of the number of articles transferred by the second transfer robot 40 in the first article group G1, which is transferred into the region R1, is 100%.

Here, because the second transfer robot 40 transfers all of the articles P for accumulating the first article group G1, the second transfer robot 40 is not required to wait for the region R1 in which an article P/articles P have already been transferred by the first transfer robot 30 to move to the second accumulation area C2, and can transfer the article P, which is to be transferred to the accumulation conveyor 20, to the second accumulation area C2 by the second transfer robot 40 without the article passing through the second pickup area A2 (set times T1 to T15).

As shown in FIGS. 7A and 7B, the ratio of the number of articles transferred by the second transfer robot 40 in the other article groups Go, which is transferred to the regions R2, R3, ... on the accumulation conveyor 20 is 50% because the first transfer robot 30 and the second transfer robot 40 are controlled in the ordinary distribution control mode for the other article groups Go (see, e.g., the other article groups Go accumulated in the region R2 on the accumulation conveyor 20 at time T15).

Focusing on the initial article group G (the first article group G1) at the start of accumulation and the second article group G after the start of accumulation, the second transfer robot 40 performs the transfer operation 1.5 times more often than does the first transfer robot 30 at the start of accumulation. (4) Characteristics (4-1)

The article accumulating device 100 according to the present embodiment is provided with a delivery conveyor 10, an accumulation conveyor 20 as an example of a movable accumulation section, a first transfer robot 30 as an example of a first robot, a second transfer robot 40 as an example of a second robot, and a control unit 50. The delivery conveyor 10 delivers articles P. The accumulation conveyor 20 for accumulating a predetermined number of articles P as a single article group G moves in a second direction D2 that is the same as a first direction D1, which is a transport direction of the delivery conveyor 10. The first transfer robot 30 takes the articles P from a first pickup area A1 of the delivery conveyor 10 and transfers the articles P to a first accumulation area C1 of the accumulation conveyor 20. The second transfer robot 40 takes the articles P from a second pickup area A2 of the delivery conveyor 10 and transfers the articles P to a second accumulation area C2 of the accumulation conveyor 20. The second pickup area A2 is positioned at the downstream side relative to the first pickup area A1 in the first direction D1. The second accumulation area C2 is positioned at the downstream side relative to the first accumulation area C1 in the second direction D2. The control unit 50 controls the first transfer robot 30 and the second transfer robot 40 so that the articles P are accumulated as the article group G on the accumulation conveyor 20. The control unit 50 controls the first transfer robot 30 and the second transfer robot 40 so that the ratio of the number of the articles P transferred by the second transfer robot 40 in an initial article group G (the first article group G1) at the start of accumulation of the articles P is greater than the ratio of the number of the articles P transferred by the second transfer robot 40 in the article group G (the other article groups Go) during ordinary operation.

With the article accumulating device 100 according to the present embodiment, the ratio of articles P transferred to the accumulation conveyor 20 by the downstream-side second transfer robot 40 in the initial article group G (the first article group G) at the start of article accumulation is greater than the ratio of articles P transferred to the accumulation conveyor 20 by the second transfer robot 40 in the article group G (the other article groups Go) during ordinary operation. Accordingly, it is possible to prevent a situation in which the region for transferring the article P has not arrived at the position to which the second transfer robot 40 can transfer the articles P when the second transfer robot 40 is to transfer the articles P from the delivery conveyor 10 at the start of accumulation. (4-2)

In the article accumulating device 100 according to the present embodiment, the control unit 50 controls the first transfer robot 30 so that at least two of the articles P delivered by the delivery conveyor 10 consecutively pass through the first pickup area A1 without being taken by the first transfer robot 30 before accumulation of the first article group G1 has been finished after the start of accumulation.

With the article accumulating device 100 according to the present embodiment, at least two of the articles P delivered by the delivery conveyor 10 consecutively pass through the pickup range of the first transfer robot 30 without being transferred by the first transfer robot 30 before accumulation of the first article group G1 has been finished. It is therefore possible to increase the ratio of articles P transferred to the accumulation conveyor 20 by the downstream-side second transfer robot 40 in the first article group G1 at the start of accumulation of the article P. (4-3)

In the article accumulating device 100 according to the present embodiment, the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 so that the ratio of the number of the articles P transferred by the second transfer robot 40 in the second and subsequent article groups (the other article groups Go) after the start of accumulation is 50%.

With the article accumulating device 100 according to the present embodiment, the ratio of the number of the articles transferred by the second transfer robot 40 in the other article groups Go is 50%, in other words, each of the first transfer robot 30 and the second transfer robot 40 operate so as to accumulate the same number of articles P. The first transfer robot 30 and the second transfer robot 40 can therefore be operated with good efficiency.

(5) Modifications (5-1) Modification A

In the initial special distribution control mode in the above-described embodiments, the control unit 50 controls the first transfer robot 30 and the second transfer robot 40 so that the ratio of the number of articles P transferred by the second transfer robot 40 is 100% in the initial article group G (the first article group G1) at the start of accumulation, but no limitation is imposed thereby.

For example, the control unit 50 may control the first transfer robot 30 and the second transfer robot 40 so that the ratio of the number of the articles P transferred by the second transfer robot 40 in an initial article group G (the first article group G1) at the start of accumulation is 75%, which is greater than the ratio of the number of the articles transferred by the second transfer robot 40 in the article group G (the other article groups Go) during ordinary operation (50%). See FIGS. 8A and 8B for the specific transfer operation of the first transfer robot 30 and the second transfer robot 40 when the ratio of the number of articles P transferred by the second transfer robot 40 in the first article group G1 is 75%.

(5-2) Modification B

In the above-described embodiments, four articles P are transferred so that two articles P are lined up in the second direction D2, which is the transport direction of the accumulation conveyor 20 and two articles P are lined up in the direction orthogonal to the second direction D2, as viewed from above, and are accumulated as a single article group G on the accumulation conveyor 20, but no limitation is imposed thereby.

For example, the article accumulating device 100 may be a device for accumulating two, six, eight, or another even number of articles P as a single article group G on the accumulation conveyor 20. The ratio of the number of articles P transferred by the second transfer robot 40 in the initial article group G (the first article group G1) at the start of accumulation is not limited to 100% as in the above-described embodiment or 75% as in modification A, and may be suitably determined in accordance with the number of articles P constituting a single article group G.

The method of accumulating the articles on the accumulation conveyor 20 in the article accumulating device 100 is an example, and it is also possible, e.g., to transfer the articles P so that other articles P overlap the articles P on the accumulation conveyor 20.

(5-3) Modification C

In the above-described embodiment, the article accumulating device 100 is used as a part of the box-packing system 1 in which the article group G is packed in a box B by the box-packing robot 200 after the articles P have been accumulated as the article group G by the article accumulating device 100, but no limitation is imposed thereby.

For example, in lieu of the accumulation conveyor 20, the article accumulating device 100 may have roller conveyor as a configuration for transporting a container having an open top, and may be configured so that the first transfer robot 30 and the second transfer robot 40 accumulate (accommodate) the articles P in the container as a moving movable accumulation section.

INDUSTRIAL APPLICABILITY

The article accumulating device according to the invention of the present application transfers and accumulates articles from an article-delivering delivery conveyor to a movable accumulation section with a plurality of robots, and is useful as a high-reliability article accumulating device for preventing articles from being left behind on the delivery conveyor.

REFERENCE SIGNS LIST 10 Delivery conveyor 20 Accumulation conveyor (Movable accumulation section) 30 First transfer robot (First robot) 40 Second transfer robot (Second robot) 50 Control unit A1 First pickup area A2 Second pickup area C1 First accumulation area C2 Second accumulation area D1 First direction D2 Second direction G1 First article group (Initial article group at start of accumulation)

Go Other article groups (Article groups during ordinary operation) P Article

CITATION LIST

PATENT LITERATURE

Patent Literature 1: Japanese Laid-open Patent Application No. 2012-188231

Claims

An accumulation device comprising: a delivery conveyor adapted to deliver articles; a movable accumulation section adapted to accumulate a predetermined number of articles as a single article group, the movable accumulation section being adapted to move in a second direction that is the same as a first direction that is a conveying direction of the delivery conveyor; a first robot adapted to take the articles from a first picking area of the delivery conveyor and to transfer the articles to a first accumulation area of the movable accumulation portion; a second robot adapted to take the articles from a second picking area of the delivery conveyor, which second picking area is positioned on the downstream side with respect to the first picking area in the first direction, and to transfer the items to a second accumulation area of the movable accumulation portion positioned at the downstream side with respect to the first accumulation area in the second direction; and a control unit adapted to control the first robot and the second robot so that the articles are accumulated as the article group on the movable accumulation section, the control unit being adapted to control the first robot and the second robot such that the ratio of the number of articles in an initial article group that is transferred by the second robot at the start of the accumulation of the articles is greater than the ratio of the number of articles in the article group that is transferred by the second robot during a normal operation.

An article accumulation device according to claim, wherein the control unit is arranged to control the first robot such that at least two of the articles delivered by the delivery conveyor pass through the first picking area successively without being picked up by the first robot before the accumulation of the initial article group is completed after the start of the accumulation.

The article accumulation device according to claim 1 or 2, wherein the control unit is adapted to control the first robot and the second robot such that the ratio between the number of articles transferred by the second robot into second and successive article groups after the start of the accumulation is 50%.