Sorting Device For Articles And Method For Sorting Articles

Abstract

A sorting device for articles has at least two main conveyor lines, each conveying consecutively arranged articles, at least two feeder devices, which respectively feed the articles to one of the main conveyor lines, at least two recognition devices for detecting a sorting destination for each article, a plurality of sorting outlets arranged at the end of each main conveyor line, each assigned to sorting destinations, and to which the articles are transported. The sorting device further has at least two connecting conveyor lines, each branching off the main conveyor lines at branch points, by way of which the articles can be conveyed from one main conveyor line to another main conveyor line. The articles can be temporarily stored in a storage device, which feeds temporarily stored articles to one of the main conveyor lines in the direction of conveyance before at least one of the branch points.

Claims

1-7. (canceled)

8. A sorting device for articles, the sorting device comprising: at least two main conveyor lines, each configured for conveying consecutively arranged articles in a direction of conveyance; at least two feeder devices configured to respectively feed the articles to one of said main conveyor lines; at least two recognition devices disposed downstream from said feeder devices in the direction of conveyance, and configured to detect a sorting destination for each article; a plurality of sorting outlets arranged at a end of each one of said main conveyor lines, said sorting outlets being assigned a given sorting destination each and being disposed for receiving the articles to their sorting destination; at least two connecting conveyor lines, each branching off from a respective said main conveyor line at a branch point and each connecting said two main conveyor lines to enable articles to be fed from one said main conveyor line to another said main conveyor line; and at least one storage device for temporarily storing articles, said storage device being disposed to feed temporarily stored articles to one of said main conveyor lines upstream of at least one of said branch points in the direction of conveyance.

9. The sorting device according to claim 8, wherein said storage device comprises at least one diverter gate arranged in one of said main conveyor lines, a return line branching off from said main conveyor line at said diverter gate and a return point to said main conveyor line arranged at an end of said return line, and wherein said diverter gate is disposed downstream of said return point in the direction of conveyance of said main conveyor line.

10. The sorting device according to claim 9, wherein at least one transport parameter for the articles on said main conveyor line is different in comparison with said return line.

11. The sorting device according to claim 8, which comprises a controller configured to control the sorting device and generating an adequate gap in a stream of articles on said main conveyor line in order to return an article from said storage device.

12. The sorting device according to claim 8, configured to sort the articles in at least three sorting passes.

13. A method for sorting articles, the method comprising: feeding the articles to at least two main conveyor lines and acquiring a sorting destination for each article; transporting the articles on the main conveyor lines in a direction of conveyance towards sorting outlets in accordance with their sorting destination; branching off at least some articles from one main conveyor line at a branch point onto a connecting conveyor line and feeding to another main conveyor line; and temporarily storing at least some articles and feeding the temporarily stored articles to one of the main conveyor lines upstream of the branch point.

14. The method according to claim 13, which comprises sorting the articles in at least three sorting passes.

Description

[0015] The invention will be explained in the following with reference to the attached drawings and the exemplary embodiment shown therein.

[0016] In the drawings:

[0017] FIG. 1 shows a schematic illustration of a first embodiment of the sorting device according to the invention;

[0018] FIG. 2 shows a schematic illustration of a further embodiment of the sorting device according to the invention.

[0019] Firstly, the sorting device according to the invention will be described with reference to the exemplary embodiment shown in FIG. 1.

[0020] The sorting device 1 shown in FIG. 1 comprises two feeder devices 2a, 2b, a first and a second group of sorting outlets 3a, 3b and two storage devices 4a, 4b. The sorting device 1 furthermore has two main conveyor lines 5a, 5b and a plurality of connecting conveyor lines 6a, 6b, 6c, 6d arranged between the main conveyor lines 5a, 5b, which connect the main conveyor lines 5a, 5b to one another. The sorting device 1 furthermore comprises a controller 7 which controls the sorting device 1 and the components thereof. The components are identified by numbers and letters. The letters serve to differentiate the otherwise identical components of the two main conveyor lines. When the reference characters are used without letters, the components of both main conveyor lines are meant.

[0021] The feeder devices 2a, 2b are designed in order to feed articles 8 onto the main conveyor lines 5a, 5b respectively. The articles 8 to be sorted by the sorting device 1 in FIG. 1 are flat postal items, such as for example letters or large letters. The feeder devices 2a, 2b are implemented in a manner known per se and for example separate an inserted batch of articles 8 to produce a stream of articles in which the flat articles 8 are fed successively to the respective main conveyor line 5a, 5b standing on edge and spaced apart from one another.

[0022] On the main conveyor line 5 the articles 8 are transported in a direction of conveyance 9 toward the respective group of sorting outlets 3. On the main conveyor line 5 the flat articles 8 standing on edge are normally transported gripped on both sides, for example by endless belts.

[0023] The two groups of sorting outlets 3a, 3b at the end of the two main conveyor lines 5a, 5b each have a plurality of sorting outlets 17a, 17b which are assigned to sorting destinations for the articles 8. The sorting outlets 17a, 17b are designed in a known manner for example as stacking compartments in which the articles 8 assigned to the respective sorting outlet 17 are output in stacked fashion.

[0024] The sorting device 1 furthermore comprises two recognition devices 10 which are designed in order to detect a sorting destination for each article. The sorting destination 11 is located for example as a recipient address on the article 8. In order to detect the sorting destination 11 a camera (not illustrated) associated with the recognition device 10 produces an image of the article 8 and detects for example by means of OCR technology (optical character reading) the sorting destination 11 from the recipient address. The detected sorting destination 11 is passed to the controller 7 which transports the article 8 to the sorting outlet 17 assigned to the sorting destination. The recognition device 10 is arranged immediately downstream of the feeder device 2 in the direction of conveyance 9.

[0025] In the embodiment shown in FIG. 1 the two storage devices 4a, 4b each have a diverter gate 12 arranged in the main conveyor line 5, a return line 13a, 13b and a return point 14a, 14b. The return line 13 runs from the diverter gate 12 as far as the return point 14 likewise arranged in the main conveyor line 5.

[0026] The connecting conveyor lines 6 arranged downstream of the storage devices 4 in the direction of conveyance 9 run in each case from a branch point 15 arranged in the main conveyor line 5 to a connecting point 16 in the other respective main conveyor line 5. At the branch point 15 the connecting conveyor lines 6 each have a branching diverter gate (not illustrated), by means of which articles 8 are either left on the main conveyor line 5, or can be branched onto the connecting conveyor line 6, by the controller 7. Furthermore, the connecting conveyor lines 6 may in each case have storage means (not illustrated), by means of which articles 8 on the connecting conveyor line 6 can be stored at least temporarily, as described for example in U.S. Pat. No. 4,615,446.

[0027] The function of sorting device 1 according to the invention will be described in the following with reference to the exemplary embodiment shown in FIG. 1.

[0028] Unsorted articles 8 are fed from the two feeder devices 2 to the two main conveyor lines 5a, 5b. By this means a stream of articles consisting of articles 8 arranged one behind the other is produced which are conveyed spaced apart from one another in the direction of the groups of sorting outlets 3. When the articles 8 pass the recognition devices 10, the sorting destinations 11 of the articles 8 are then detected and each article 8 is assigned a sorting outlet 17 in one of the two groups of sorting outlets 3a, 3b according to the detected sorting destination 11.

[0029] Since different sorting destinations 11 are assigned to the groups of sorting outlets 3a, 3b, it can happen that an article 8 is located on a main conveyor line 5a which does not route said article 8 to the correct group of sorting outlets 3b. In this case the article 8 must be fed to the respective other, correct main conveyor line 5b by way of one of the connecting conveyor lines 6. Said feed is however only possible if a free space is present in the stream of articles on the other main conveyor line 5b. If said free space is not present, because for example all the articles 8 on the main conveyor line 5b are correctly assigned, the article 8 from the main conveyor line 5a cannot initially be fed. In this case one also speaks of an unbalanced load of the system. In this case the article 8, which is intended to be transferred from the main conveyor line 5a onto the main conveyor line 5b, is stored temporarily in the storage device 4a until it can be fed by way of a connecting conveyor line 6 to the main conveyor line 5b.

[0030] In order to temporarily store the article 8, the diverter gate 12a is operated by the controller 7 so that the article 8 is diverted onto the return line 13a. At the end of the return line 13a the article 8 is reintroduced onto the main conveyor line 5a at the return point 14a. Since the return point 14 is in each case arranged upstream of the diverter gate 12 in the direction of conveyance 9 on the main conveyor line 5, the article 8 is stored temporarily for a certain storage time in the storage device 4. The storage time depends essentially on the transport speed and the article spacings on the return line 13, which may differ from the transport speed on the main conveyor line 5. The temporarily stored and now returned article 8 can be transferred from the main conveyor line 5a onto the main conveyor line 5b by way of one of the connecting conveyor lines 6a, 6c if a corresponding free space is present on the main conveyor line 6b after the temporary storage. Said free space can have been created in the interim by the controller 7, for example by means of a temporary stoppage of the feeder device 2b or a temporary storage of an article 8 in the storage device 4b.

[0031] The storage devices 4 can additionally or alternatively also be utilized for the temporary storage of articles 8 for which it has not yet been possible for the recognition device 10 to detect any sorting destination 11 up to reaching the diverter gate 12. This means that it is unclear for said article 8 as to whether it is assigned to the correct main conveyor line 5. As a result of diverting said article 8 into the storage device 4, the sorting destination 11 can be detected during the storage time and the article 8 can subsequently be transported to the correct group of sorting outlets 3a, 3b. Since the return point 14 of the storage device 4 is in each case arranged upstream of the branch points 15 in the direction of conveyance 9, after the articles 8 have been stored in the storage device 4 a decision can be taken regarding a means of transport required on one of the connecting conveyor lines 6.

[0032] A path length L.sub.1 from one of the feeder devices 2a, 2b as far as the return point 14a, 14b is designed to be shorter than a path length L.sub.2 of the return line 13a, 13b. This has the advantage that the feeder device 2a, 2b can be stopped in order to form a gap when an article has been introduced onto the return line 13a, 13b. Alternatively, storage means would need to be employed on the path L.sub.2.

[0033] In the following the invention will be described with reference to the further exemplary embodiment of the sorting device 1 in FIG. 2. For the sake of simplicity, only the differences from the sorting device 1 in FIG. 1 will be discussed.

[0034] In contrast to the embodiment illustrated in FIG. 1 the sorting device 1 in FIG. 2 comprises two further storage devices 4c, 4d which are arranged downstream of the storage devices 4a, 4b. In this situation the diverter gates 12c, 12d are in each case arranged downstream of the branch points 15 and the connecting points 16 of the connecting conveyor lines 6. The return points 14c, 14d on the other hand are in each case arranged upstream of the branch points 15 and the connecting points 16. Further articles 8 can be stored by means of the additional storage devices 4c, 4d.

[0035] As an alternative to the embodiment illustrated in FIG. 2, in an embodiment of the invention not illustrated the storage devices 4a, 4b can be omitted and the sorting device 1 operated only with the storage devices 4c, 4d.