A METHOD AND ARRANGEMENT FOR TRANSFERRING ARTICLES

Abstract: The invention relates to a method and to an arrangement for transferring articles (1) from a conveyor (2) through a rack (3) or magazine. The articles (1) are gripped one at a time by a gripping device (8, 8a) and are moved from the conveyor (2) while being brought to a correct position of alignment in rela­ tion to the rack (3), whereafter the article (1) is placed in the rack. In accordance with the mvention the article transfer is ef­ fected in at least two transfer stations (5, 6) which work in parallel and which are arranged one after the other along the conveyor path (1), each transfer station including an industrial robot (7, 7a). A plurality of racks (3) are moved sequentially along a path (4) which extends through all transfer stations (5, 6). Only a given part of each rack (3) is filled in each transfer station (5, 6), such that the rack (3) will be completely filled subsequent to passing through all transfer station (5, 6).

Description: The present invention relates to a method in accordance with the first part of claim 1. The present invention also relates to an arrangement for transferring articles from a conveyor on which the articles are advanced sequentially, one at a time, to a rack or magazine, in which the articles are placed close together in given locations, in accordance with the first part of claim 4. The requirement of transferring articles from a conveyor or transporter is found in various industrial processes, in which the articles are advanced sequentially, one at a time, for example from a working or processing station to a rack or magazine, in which the articles are placed close together, whereafter the rack or magazine is used to transport the articles to a further processing station or to a consumer station. This is the case, for example, with articles that comprise pressed sheet-metal elements which are discharged singly from the press and which shall then be transferred to a rack for transportation to an assembly station for example. It is important in cases such as these that the rack is completely filled with articles or objects, which are therewith placed in close side-by-side relationship so as to utilize the space available to the best possible extent. Previously the work of transferring the articles from the conveyor to the racks has been carried out manually. This work, however, is both heavy and troublesome, and consequently attempts have been made to mechanise the work. Those attempts of mechanising such work, however, have not hitherto met with success. The arrangements used herefor have been expensive, complicated and type bound, and also require a relatively large amount of space. Another drawback with the known arrangements is that they are unable to operate quickly enough to transfer all of the articles discharged to a conveyor from, for example, a modern sheet-metal pressing plant. A method and an arrangement for transferring articles from a conveyor to a number of boxes is previously known from DE-A-2 123 986. A plurality of transfer stations are used, but transfer stations transfer the articles to different positions in a transverse direction. Further the articles are not given a specific orientation relative to the boxes, but are merely allowed to hang rather freely. The object of the present invention is to provide a method and an arrangement of the kind mentioned in the introduction which avoids these drawbacks and which will enable articles to be transferred quickly and effectively. This object is achieved by means of the inventive method and the inventive arrangement having the characteristic features set forth in respective claims 1 and 4. The invention will now be described in more detail with reference to the accompanying drawing, which illustrates in perspective one embodiment of an arrangement according to the invention for carrying out the inventive method. The arrangement illustrated in the drawing is intended to be placed adjacent a sheet-metal press plant, from which pressed articles 1, in this case door panels for vehicle doors, are fed onto a conveyor or transporter 2 which moves from left to right as seen in the drawing. The articles are placed in side-by-side relationship on the conveyor, with a given spacing between mutually adjacent articles. The articles 1 are to be transferred into racks or magazines 3 which move along a path 4, as described in more detail hereafter. Two transfer stations 5 and 6 are provided for the transfer of articles, these stations being located one behind the other along the conveyor 2. The two transfer stations 5 and 6 have mutually the same construction and function, and hence the various corresponding components of the stations are identified with mutually the same reference numerals, although the components of the station 6 are further identified by the suffix a . The most important component of a transfer station of this kind is an industrial robot 7 and 7a, located between the conveyor 2 and the path 4. The robot 7 and 7a is provided with a respective gripping device 8 and 8a, which in the illustrated embodiment comprise suction devices which hold an article 1 with the aid of a vacuum. In the simplest case, the robot 7 and 7a collects an article 1 directly from the conveyor 2, with the aid of respective gripping devices 8 and 8a, and move the object while turning the same about mutually different axes in a manner to bring the object into a correct position of alignment for introduction into the rack 3, whereafter the robot 7 and 7a places its respective article into the rack. The robot 7 located in the transfer station 5 takes every alternate article 1 from the conveyor 2, while the remaining articles 1 on the conveyor 2 are collected therefrom by the robot 7a located in the transfer station 6. In the case of the illustrated embodiment of the arrangement, however, the robots 7 and 7a do not collect the articles 1 directly from the conveyor 2. Instead, each transfer station 5, 6 is equipped with a respective feed device 9 and 9a which transfers respective articles 1 from the conveyor 2 to a respective support device 10 and 10a, from where the articles are collected by the gripping devices 8 and 8a of respective robots 7 and 7a. The robots 7 and 7a then place the articles in carrier devices 11 and 11a in a respective intermediate storage means 12 and 12a, therewith to form a group of articles 1 on respective carrier devices 11 and 11a. When the group of collected articles has reached a given size, the carrier devices 11 and 11a in the intermediate storage means 12 and 12a are moved so as to introduce the group of articles into the rack 3. It is conceivable, of course, for the robots 7 and 7a to transfer respective articles to the rack 3 directly from respective support devices 10 and 10a. According to the invention, the racks 3 are moved along the path 4 in a given manner. As will best be seen from the half-filled rack 3 located between the illustrated transfer stations 5 and 6, each rack 3 has provided thereon inwardly projecting supports which divide the available space in the rack into a number of locations for the articles 1. Each such location may be intended for a single article or for a group of articles, this latter case being the one illustrated. The racks are advanced stepwise along the path 4 in a manner such that subsequent to the deposit of a group of articles in one location, each rack is stepped forwards through a distance such as to bring the next location in the rack into its correct position for receiving the next group of articles 1. Alternatively, the intermediate storage means 12 and 12a may be advanced stepwise, to achieve the same positioning of the groups of articles in relation to the rack 3. Furthermore, the path 4 is advanced in a manner such that each rack 3 in the transfer station 6 is only filled to half its capacity, whereafter the rack is advanced to an intermediate position and then finally to the transfer station 5, where the remainder of the rack is filled. An empty rack 3 is advanced at the same time into the transfer station 6. In that case when the robot 7 and 7a transfer articles 1 directly into the rack 3, the desired transfer of articles can be achieved either by advancing the rack 3 stepwise or by programming the robot 7 and 7a to introduce the articles 1 into mutually different locations in the rack, or by a combination of these measures. When commencing operation, an empty rack 3 is placed in each transfer station 5 and 6. When each of the racks 3 has been filled to half of its capacity, the rack in the transfer station 6 is advanced to the intermediate position and an empty rack is advanced into the transfer station 6. The rack 3 in the transfer station 5, on the other hand, is not moved. The fresh rack located in the transfer station 6 is then filled to half its capacity, while the remaining capacity of the first rack in the transfer station 5 is filled in said station. At the same time, the half-filled rack is located in the intermediate position. This completes the starting process, and the process is continued in the aforedescribed manner. The invention is not restricted to the aforedescribed embodiment, and modifications can be made within the scope of the following claims.

Claims: 1. A method for transferring articles (1) from a conveyor (2), on which the articles are advanced one after another, to a rack (3) or magazine in which the articles (1) are placed close together in given locations, the transfer being performed in at least two transfer stations (5, 6) arranged one after the other along the conveyor (2) and working in parallel, whereby in each of the transfer stations (5, 6) one article (1) at a time is taken from the conveyor (2) by means of a transfer device and is moved and aligned to correct orientation relative to the rack (3), whereupon it is inserted in its given location in the rack (3), said rack (3) being moved along a path (4) which extends through all transfer stations (5, 6), characterized in that, in all transfer stations (5, 6), each article (1) is moved, by means of the transfer device, to the same position in the transverse direction in relation to the path (4) of the rack (3), and in that in each transfer station (5, 6) the rack (3) is filled with articles only in a predetermined portion, limited in the direction of movement of the rack (3) along the path (4), in such a way that the rack (3) subsequent to passing through all transfer stations (5, 6) is completely filled. 2. A method according to Claim 1, characterized in that each article (1) in each transfer station (5, 6) is moved separately to the rack (3) and introduced thereinto, with the aid of the transfer device; and in that the rack and/or the transfer device is advanced through a distance along the path (4) corresponding to the distance between two given locations in the rack between each transfer operation. 3. A method according to Claim 1, characterized in that each article (1) in each transfer station (5, 6) is moved separately, with the aid of the transfer device, to an intermediate storage position (12), and in that the articles (1) are moved in groups from said intermediate storage position into the rack (3), and the rack is advanced through a distance along the path (4) corresponding to the space required in the rack (3) to accommodate the group of articles (1) in question between each transfer operation. 4. An arrangement for transferring articles (1) from a conveyor (2) on which the articles are advanced sequentially one-by-one to a rack (3) or magazine in which the articles (1) are placed close together in given locations, at least two transfer stations (5, 6) being arranged for the transfer, said transfer stations being positioned one after the other along the conveyor (2) and working in parallel and each including a transfer device (7, 7a) comprising gripping devices (8, 8a) for gripping and firmly holding an article (1), said transfer device (7, 7a) being arranged for transferring the article (1) held by the gripping device (8, 8a) and bringing the article into a correct position of alignment in relation to the rack (3), and for inserting the article into the rack (3), which is arranged to be moved along a path (4) through all transfer stations (5, 6), characterized in that the transfer device in each transfer station comprises an industrial robot (7, 7a), and in that the path (4) is arranged to advance the rack (3) in a manner such that only a predetermined portion, limited in the direction of movement of the rack (3) along the path (4), of the rack (3) is filled in each transfer station (5, 6), such that the rack (3) is completely filled subsequent to passing through all transfer stations (5, 6). 5. An arrangement according to claim 4, characterized in that the industrial robot (7, 7a) in each transfer station (5, 6) is arranged to deposit each article (1) in an intermediate storage position (12, 12a), in that each intermediate storage position (12, 12a) includes carrier devices (11, 11a) for collecting a group of articles (1), and in that the carrier devices (11, 11a) are constructed to introduce the group of articles (1) into the rack (3), subsequent to said rack having been advanced through the requisite distance along the path (4).

Inventors: HULTBERG, JIMMY
Applicants: AB VOLVO
Application year: 1987
Main classification: B65G47
IPC codes: B65B5, B65G61, B65G65, B65G1, B65G47