EP0589821A1

EP0589821A1 - Sorting apparatus and sorting unit for the same

Info

Publication number: EP0589821A1
Application number: EP93610053A
Authority: EP
Inventors: Mogens Erup Larsen
Original assignee: Dansk Vaskeri Teknik AS
Current assignee: DVT SORTTECH A/S
Priority date: 1992-09-25
Filing date: 1993-09-22
Publication date: 1994-03-30
Anticipated expiration: 2013-09-22
Also published as: ATE166931T1; DE69318918D1; ES2120488T3; DE69318918T2; DK171210B1; EP0589821B1; DK119392D0; DK119392A

Abstract

A sorting apparatus for laundry comprises a feeding conveyor (A), a reading conveyor (B), an intermediate conveyor (C) and a sorting section (D) with a number of sorting units (1) each incorporating an inclined conveyor (2). Items of laundry are individually conveyed from position E and distributed to a number of destinations (5). Between each conveyor (2) there is arranged a sorting unit (1) comprising at least one moveable or pivotable plate. At the end of the sorting apparatus there is arranged an additional sorting shaft (6).

Each item carries an electronic transponder which is read by the antenna (21) by the reading conveyor (B). The reading is entered in the control unit of the apparatus which controls the sorting by applying information from encoders (23, 23', 23'') and photo cell arrangements (24, 24', 24'') by the individual conveyors.

Description

Background of the invention

The invention relates to an apparatus for sorting identifiable items, for example laundry or similar items, and as further described in the introduction to claim 1.
A number of different apparatuses for sorting laundry are known and for sorting the laundry prior to as well as after the washing. In large-scale laundries handling for example hospital clothes such as coats and the like, the clothes are often provided with an identification tag such as an electronic transponder, which is permanently arranged in the clothes and which may therefore be used for controlling sorting processes etc. prior to as well as after washing of the clothes.
A known sorting apparatus applies compressed air in connection with the sorting of the clothes in that the compressed air is used for pushing the clothes off the conveyor at the point of destination. This system is disadvantageous when sorting clothes prior to the washing because impurities and the like from the clothes are stirred up. Moreover, such sorting systems make a lot of noise.
Another known apparatus is based on transferring individually conveyed clothes items on a conveyor belt to one of two destinations by moving or displacing the conveyor. This results in a relatively slow, low-capacity apparatus since it takes relatively long time to move the conveyor, or one end thereof, due to its weight.

Advantages of the invention

The sorting apparatus according to the invention and with the features disclosed in the characterising part of claim 1 is advantageous in that the rearrangement of the sorting units following a choice of destination takes place very quickly and at a low energy consumption because only few mechanical parts require rearrangement. Furthermore, the items are mainly simply moved forward in a steady but quick movement so that no unnecessary stir of any impurities from the clothes during the sorting will occur.
By a suitable combination of the rise and rate of speed of each sorting conveyor the result is that the items will leave one of the conveyors along a curve (trajectory of discharge) which precisely allows the items to overcome the distance to the next conveyor and land on the front part thereof. If sorting to a destination downwards is desired, this is achieved by rearranging the plate or plates of the sorting unit whereby the curve is cut and the plate or plates will operate as guide plates for the change in direction. The combined action of the guide plates and the continued movement of the conveyor will pull the items downwards by the squeezing action between the conveyor and the guide plates.
The invention is particularly developped for sorting laundry where each piece of laundry has a transponder for identification for which reason the invention is now explained in connection with the sorting of laundry, but it is obvious to a person skilled in the art that also other identification methods are applicable, e.g. bar codes, colour or colour codes, pattern recognition etc. Furthermore, it is obvious to a person skilled in the art that also other items than laundry may be sorted with the apparatus according to the invention, for example newspapers, consignments, foodstuffs, parcels, spare parts of any kind, semi-manufactures etc.
By designing the apparatus according to the invention as disclosed in the characterising part of claim 2, an apparatus is obtained which very reliably sorts the items so that they reach the correct destination.
By designing the apparatus according to the invention as disclosed in the characterising part of claim 3, a sorting apparatus is obtained which may extend at the same level over a long distance, and for each conveyor added it is possible to have a further point of destination.
By designing the apparatus according to the invention as disclosed in the characterising part of claim 4 or claim 5, there is obtained a simple and reliable construction having a very low energy consumption and which can sort the clothes almost noiselessly.
By designing the apparatus according to the invention as disclosed in the characterising part of claim 6, claim 7 or claim 8, there is obtained advantageous mechanical constructions with a high degree of reliability and arranged such that quick and safe sorting may take place. Should it nevertheless happen that an item is so dirty or wet that it sticks to the conveyor, it will in most cases still be sorted correctly. The apparatus is therefore very well suited for sorting dry as well as wet clothes.
Each item will usually be provided with an identification tag, for example a transponder, which is read. The read data are used for controlling the sorting apparatus which is adapted in such a manner that the position and size of each item are recorded and form part of the control.
The invention also relates to an independent sorting unit for use in sorting apparatuses, and as disclosed in the characterising part of claim 9 or claim 10. With such sorting units and a number of conveyor belts it is possible to build up a sorting apparatus. A number of different conveyors or conveyor belts may be used if merely they can convey the clothes items at an adequate speed. With the sorting unit according to the invention it is therefore possible to build up a sorting apparatus of any size and thus cover almost any sorting requirement for laundry and similar items which are placed individually and freely on a conveyor.

The drawing

The invention will now be further explained in connection with a preferred embodiment of the invention, wherein

fig. 1: is a complete sorting apparatus for laundry,
fig. 2: is the actual sorting section, at a larger scale, according to the invention having three sorting belts and three sorting units, and
fig. 3: is a sorting unit at an even larger scale.

Description of the embodiment

Fig. 1 shows a sorting apparatus for laundry comprising a feeding conveyor A, a reading conveyor B, an intermediate conveyor C and a sorting section D with three sorting conveyors 2 and three sorting units 1 mounted on a common longitudinal supporting profile 17 which is carried by a number of columns 19 standing on a base 20, e.g. a floor.
The apparatus is adapted for sorting laundry which individually and spaced apart is placed on the feeding conveyor A at position E. The laundry is placed manually or mechanically on the feeding conveyor and with an equal space of at least 50-60 cm between each clothes item.
The laundry is sorted in the apparatus in the following manner: Clothes items are individually conveyed from the feeding conveyor A to the reading conveyor B where an antenna 21 is placed below the belt for reading transponders fixed in or on the clothes. To ensure a suitably close contact between each transponder and the antenna 21, there is arranged a quide plate 22 above the conveyor and this guide plate will prevent the clothes or parts thereof from passing the antenna at too great a distance. Then the items are conveyed to the intermediate conveyor C from where they are further conveyed to the sorting section D and sorted out into the distinations 5.
The entire sorting process is controlled by an electronic control unit comprising a programmable unit, such as a PLC, which receives a number of data from the sorting apparatus. The conveyor A comprises a revolution counter 23, and the conveyor B comprises likewise a revolution counter 23', said revolution counters being socalled encoders, and each sorting conveyor 2 in the sorting section D similarly has a revolution counter 23'' in the form of an encoder.
By the passage between the feeding conveyor A and the reading conveyor B, a short distance from the antenna 21, there is arranged a photo cell which partly registers that a clothes item is on its way and partly triggers the antenna 21 so that it is ready for reading the transponder in the clothes. At the same time the photo cell arrangement 24 measures the length of the clothes item in the travelling direction. At the end of the intermediate conveyor C there is also arranged a photo cell arrangement 24' and on each conveyor 2 there is likewise arranged a photo cell arrangement 24'' in that these photo cell arrangements are used for readjusting the sorting apparatus in case a clothes item has been displaced, for example due to slip or compression, so that the control circuit of the sorting apparatus will always have correct information on the individual clothes items on the conveyor, ie. where they are situated and the actual extension thereof on the conveyor.
As will appear from fig. 2, the individually conveyed items in the sorting section D will be conveyed by the top end of each of the inclined conveyors 2 to a sorting unit 1 which will either allow the clothes to fall down through a shaft for a sorting destination 5 or transfer the item to the next conveyor. The conveyor belts 2 are endless belts made of plastic or rubber and moved at a comparatively high rate of speed, e.g. of the order of 1 m/sec in the travelling direction which is indicated by an arrow by each conveyor. The functioning of the sorting unit 1 will be explained below with reference to fig. 3. By the end of the sorting apparatus there is provided a further shaft 6 such that at the end of the last sorting conveyor 2 there are two sorting destinations 5.
All the items which are placed on the sorting apparatus by the position E may therefore electronically be sorted out to the destinations marked 5. Three sorting conveyors with three sorting units may accordingly transfer the items to four different destinations.
It is obvious to a person skilled in the art that sorting apparatuses of this kind may be extended to form very big apparatuses in that there is added an additional sorting destination each time the apparatus is extended by a sorting conveyor 2 and a sorting unit 1. It is also clear from figs. 1 and 2 and the explanation thereto that the sorting section may extend at the same level as far as desired since the individual sorting conveyors 2 take an inclined upwards position in the travelling direction as shown in the drawing.
The functioning of the sorting unit 1 is now explained further with reference to fig. 3 of the drawing showing a sorting unit at a larger scale arranged between two conveyor ends 2. Each sorting conveyor 2 comprises an endless, motor-driven belt 16 extending at either end around a roller or cylinder 15.
Each sorting unit 1 which is arranged immediately between two conveyor ends 2 comprises in the shown embodiment two movable plates 7, 8. The plates are mounted pivotably about substantially horizontal axes 13, 14 and can be manoeuvred by working cylinders 10, preferably compressed-air cylinders. The plates 7, 8 are shown in two positions, one position fully drawn up and one position with a dotted line and marked 7' and 8'.
When the plates 7, 8 are in the position shown by the fully drawn line, the clothes items, due to the speed of the belt 16, will pass in a curve shown by the arrows 4 in the form of a throw from one conveyor to the next one. For this purpose the sorting unit has an opening 18 so that the clothes can be freely transferred from one conveyor and down onto the next one as shown by the arrows 4. One of the plates, namely the plate 7, which extends directly from one conveyor end and downwards in the travelling direction to the next conveyor end has an edge or bending 11 so that any clothes items which will stick to the belt 16 due to moisture or dirt will nevertheless be transferred to the belt of the next conveyor. The readjustment of the plates 7, 8 to the position 7', 8' results in that a clothes item cannot be transferred to the next conveyor because the plates 7', 8' blocks the way, and the item will therefore hit the plates 7' or 8' and then fall vertically down through the shaft 3 to the position 5 as indicated by the dotted arrows 9.
One end of the working cylinders 10 is secured to the frame or the like of the sorting unit 1, for example the horizontal base part 12 in such a manner that they are pivotable in their suspension point. Compressed-air cylinders as working cylinders are preferably used since these may be readjusted in a few seconds, preferably in 0.2-0.3 seconds, so that even at the above-mentioned high rate of speed of the belt of the conveyors 2 it is possible to readjust the plates 7, 8 between each clothes item if so required. Under the shaft 3 by the destination 5 there may be arranged a bag, a waggon or the like for collecting sorted clothes.

Claims

Sorting apparatus (D) for identifiable items, for example laundry or similar items, which are individually conveyed on one of a number of conveyors (2) arranged in series and from there distributed to a number of destinations (5), characterised in that
- each conveyor (2) shows a rise and a rate of speed in the travelling direction which are sufficiently high to allow the items to leave the conveyor individually in a curve at one end thereof,

- a sorting unit (1) is arranged by each conveyor at the end where the items leave same, and

- each sorting unit comprises at least one moveable or pivotable plate (7, 8) for selection of destination.
Sorting apparatus according to claim 1, characterised in that each sorting unit comprises two plates (7, 8) which can each be positioned in one of two positions.
Sorting apparatus according to claim 1 or 2, characterised in that each conveyor (2) is arranged in an upwardly inclined position in the travelling direction so that the items leave the conveyor along a curve allowing the items to overcome the distance between the conveyor and the following conveyor via a sorting unit (1).
Sorting apparatus according to claim 1 or 2, characterised in that each plate (7, 8) is adapted to be pivoted about a substantially horizontal axis (13, 14) manoeuvred by a driving mechanism, preferably a working cylinder (10).
Sorting apparatus according to claim 1, characterised in that one of the sorting destinations by each sorting unit (1) is constituted by the start of the following conveyor.
Sorting apparatus according to any one of claims 1-5, characterised in that all conveyors are alike and consist of an endless, motor-driven belt (16) extending over a roller or cylinder (15) at either end, and that all sorting units (1) are similarly alike in that each conveyor comprises a revolution counter (23'') and at least one photo cell arrangement (24'').
Sorting apparatus according to any one of claims 1-6, characterised in that one of the plates (7) is arranged such that in one of its positions it extends in a downwards inclined, forward direction from one conveyor to the next one.
Sorting apparatus according to any one of claims 1-7, characterised in that each sorting unit (1) comprises a downwardly facing shaft (3) and that the last sorting unit in the series comprises an additional shaft (6) situated where the next conveyor was supposed to start.
Sorting unit for use in a sorting apparatus according to any one of claims 1-8, characterised in that each sorting unit is an independent unit comprising at least one plate (7, 8) which can be positioned in one of two positions manoeuvred by a driving mechanism, preferably a working cylinder (10), in that the unit comprises a downwardly facing shaft (3) and an opening (18) where the shaft and the opening define sorting destinations.
Sorting unit according to claim 9, characterised in that at least one of the plates (7, 8) is adapted to allow blocking of the opening (18) in one of its positions.