Abstract:
A sorting device including successive load carrying platforms having a front edge and a rear edge for supporting products to be sorted on a supporting surface, a conveying mechanism conveying the load carrying platforms in a conveying direction along a conveying path, a sorting mechanism including plural pusher elements pushing a product to be sorted sideways off at least one supporting surface at a desired sorting location. The pusher elements each extend above at least one load carrying platform and are arranged for being jointly conveyed with the at least one load carrying platform in the conveying direction. A drive mechanism moves the at least one pusher element sideways at the desired sorting location. An arcuate shape of a front edge of a load carrying platform, as seen in top plan view, abuts an arcuate shape of a rear edge of a next load carrying platform.

Description:
The present invention relates to a sorting device for sorting products, comprising successive load carrying platforms having a front edge and a rear edge for supporting products to be sorted on a supporting surface thereof, conveying means for conveying the load carrying platforms in a conveying direction along a conveying path, sorting means comprising a plurality of pusher elements for pushing a product to be sorted sideways off at least one supporting surface at a desired sorting location using at least one pusher element which pusher elements each extend above at least part of said at least one load carrying platform and which are arranged for being jointly conveyed with said at least one load carrying platform in the conveying direction, and drive means for moving said at least one pusher element sideways at a desired sorting location. 
     BACKGROUND OF THE INVENTION 
     In 2007, a sorting system called BAXORTER, in particular for automated luggage handling, was put on the market by Vanderlande Industries Nederland B.V. Said known sorting system makes use of an endless train of rectangular load carrying platforms having a length of about 1.2 m, directly above which sorting beams are provided, which can be mechanically controlled at a sorting location to move from one longitudinal side to the other longitudinal side of the load carrying platform and push a product present on said load carrying platform, for example a piece of luggage, off the load carrying platform upon making said movement. Closing plates are provided between the load carrying platforms at both ends of each load carrying platform, the object of said closing plates being to fill the space between load carrying platforms so as to prevent objects getting between the load carrying platforms, which could lead to damage and malfunctions. The closing plates of adjacent load carrying platforms overlap and are provided with a curved outer edge oriented towards the respective adjacent load carrying platform, the curved outer edges of which overlapping closing plates cross one another. The aforesaid arcuate shape is necessary in order to be able to pass through bends. Because of the aforesaid arcuate shape, a triangular surface is present between the overlapping closing plates on the two opposite outer sides thereof, which surface is not screened by the closing plates themselves and which may need to be screened separately by further closing elements that are movable with respect to one or both closing plates. All in all, several measures need to be taken to realise a so-called closed deck as much as possible so as to reduce the risk of objects, for example straps of pieces of luggage, getting under or between the load carrying platforms. The object of the present invention is in any case to provide a constructionally relatively simple solution for realising a closed deck in sorting devices of the kind referred to in the introduction. 
     Since many years, Vanderlande Industries Nederland B.V. have furthermore marketed a sorting system under the name of POSISORTER. Said sorting system makes use of transversely oriented carriers arranged relatively close behind each other, along which pusher shoes are movable in the longitudinal direction of the carriers, so that products, such as packages, present on a number of successive carriers can thus be pushed off said carriers by the pusher shoes at a sorting location. The carriers follow an endless path in a vertical circuit. Only the upper half of said circuit can be utilised for sorting products. In said upper half, as in the lower half for that matter, the carriers follow a rectilinear conveying path. To increase the sorting capacity, EP-A1-782 966 discloses a comparable sorting system comprising carriers and pusher shoes movable along the carriers, with the endless circuit extending in the horizontal plane. So far it has not been possible, however, to be commercially successful on the market with such a system. The object of the invention is furthermore to provide an alternative to sorting systems such as the POSISORTER which has commercial possibilities, which alternative distinguishes itself in that the entire length of the conveying path can be utilised and wherein, in addition, the aforesaid closed deck principle is maintained not only in rectilinear parts of the conveying path but also in curved parts. 
     SUMMARY OF THE INVENTION 
     In order to accomplish the above objects, both the front edge of each load carrying platform and the rear edge of each load carrying platform are arcuate in shape, seen in top plan view, with the arcuate shape of the front edge of a load carrying platform abutting the arcuate shape of the rear edge of a next load carrying platform located at the front of the respective load carrying platform. Because of the aforesaid arcuate shape of the abutting edges of adjacent load carrying platforms, each load carrying platform can pivot with respect to an adjacent load carrying platform about a pivot axis that coincides with the centre of the arcuate shape in question without the closed nature of the transition between the respective load carrying platforms being lost. Add to this the fact that precisely because of the arcuate shape, the gap between the load carrying platforms, which is practically inevitable and which is logically arcuate in shape as well, reduces the risk of objects getting between the load carrying platforms in comparison with a rectilinear gap that would have the same width. 
     To simplify the drive of the pusher elements, the drive means preferably comprise at least one driver for each pusher element, which driver is connected to an associated pusher element via connecting means. Each pusher element can thus be driven via said at least one driver. 
     The aforesaid connecting means preferably extend through at least one through slot in the at least one associated load carrying platform. The pusher elements and the associated drivers can thus be arranged comparatively close together, thus making it possible to use connecting means of very simple design as well. The use of a through slot in a load carrying platform in principle involves the risk of objects getting jammed in the slot. Tests have shown, however, that in practice this risk is limited and, in addition, can be further reduced by taking additional measures, for example providing brushes which extend within the slot, along which the connecting means can move. 
     In particular if the sorting device according to the invention is designed for using only one pusher element for each product to be sorted, the pusher element in question needs to have dimensions approximately equal to the dimensions of the product to be sorted, seen in the conveying direction. As the dimensions in question increase, it will be advantageous if the sorting means comprise two drivers for each pusher element, which drivers are each connected at different positions to the associated pusher element via the connecting means, so that a single pusher element can push a product off an associated load carrying platform in a stable manner at a sorting location. 
     It is furthermore preferable in that connection if a slot is provided in said at least one associated load carrying platform for each of the two drivers, through which slot the associated connecting means extend. 
     The two slots in question are furthermore preferably provided in two different load carrying platforms. The dimensions of the load carrying platforms can thus remain limited, at least in the conveying direction, whilst nevertheless comparatively long pusher elements can be used, by means of which comparatively large products, such as packages or pieces of luggage, can be individually sorted. The advantage of using load carrying platforms having limited dimensions is that it is possible to pass through comparatively sharp bends. 
     The above positive effects can be further enhanced if at least one intermediate load carrying platform is provided between the two different load carrying platforms provided with the respective slots, which at least one intermediate load carrying platform is furthermore preferably free from slots, so that the intermediate load carrying platform is easier and thus cheaper to produce. In addition, the risk of objects getting jammed in the sorting device is thus further reduced. 
     To compensate for the change in the spacing between the two slots associated with a single pusher element when passing through bends, it is preferable if the pusher element comprises at least two pusher element parts which are telescopically movable relative to each other for the purpose of changing the length of the pusher element, and/or if the pusher element is connected to at least one of the associated pusher elements by the connecting means in such a manner as to be movable in a longitudinal direction of the pusher element. 
     Said at least one slot is preferably oriented perpendicular to the conveying direction, so that the slot takes up as little length of the associated load carrying platform as possible and the pusher element will furthermore not move in the conveying direction with respect to the load carrying platform during movement of the moving means. 
     A very suitable way of driving the pusher elements is obtained if the drive means comprise a stationary guide oriented at an angle relative to the conveying direction at the sorting location, with which stationary guide said at least one driver can be selectively caused to interact. 
     Alternatively it may also be very advantageous if the drive means comprise at least one driving motor for each pusher element, which driving motor is connected to a load carrying platform associated with the pusher element for joint transport in the conveying direction with the respective load carrying platform, thus providing a much greater degree of freedom with regard to the exact position where the drive means are operative, and rear the actual sorting process takes place, therefore. 
     According to a very important preferred embodiment, adjacent load carrying platforms are arranged in line with each other. Thus, one large joint supporting surface is created along the full length of the conveying path along which the sorting device moves. 
     In order to further reduce the risk of objects getting jammed in gaps formed between abutting front and rear edges of the adjacent load carrying platforms, it is preferable if adjacent load carrying platforms overlap at the location of the associated abutting front and rear edges, in which case adjacent load carrying platforms are arranged in line with each other, as described with reference to the preceding preferred embodiment. 
     From a practical point of view, said overlap can be realised in an advantageous manner if the abutting front and rear edges have a complementary stepped configuration, seen in vertical section parallel to the conveying direction and/or if the abutting front and rear edges have a parallel inclined configuration, seen in vertical section parallel to the conveying direction. An overlap realised in this way makes it possible in a relatively simple manner, in spite of the overlap, to remove a single load carrying platform from the train of load carrying platforms and replace it by another load carrying platform. 
     An alternative solution to the problem of the risk of objects getting between adjacent load carrying platforms is realised if successive load carrying platforms are provided with aligned grooves at their facing sides, in which a (preferably strip-shaped) closing element is provided. Such a closing element not only provides a closure, but it can also provide a correct vertical alignment of the adjacent load carrying platforms relative to each other. 
     A very suitable way of driving the sorting device as a whole is realised if the conveying means comprise an elongated flexible conveying element under the load carrying platforms, which conveying element is provided with links which can pivot about vertical pivot axes relative to each other, whilst each load carrying platform is connected to a link. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be explained in more detail by means of a description of two preferred embodiments of a sorting device according to the invention, in which reference is made to the following figures: 
         FIG. 1  is a perspective view of part of a sorting device according to a first preferred embodiment of the invention; 
         FIG. 2  is a top plan view, with transparent load carrying platforms, of part of the sorting device of  FIG. 1 ; 
         FIG. 3   a  is a top plan view of part of the sorting device of  FIG. 1  during operation; 
         FIG. 3   b  is a side view of part of the sorting device of  FIG. 3   a;    
         FIG. 4  is a top plan view of a second preferred embodiment of the sorting device according to the invention; 
         FIG. 5  is a top plan view of the sorting device of  FIG. 4  passing through a bend; 
         FIG. 6   a  is a vertical sectional view along the line VI-VI in  FIG. 4  at the transition between two successive load carrying platforms; 
         FIG. 6   b  is a sectional view corresponding to  FIG. 6   a  of an alternative embodiment; and 
         FIG. 6   c  is a sectional view corresponding to  FIG. 6   a  of another alternative embodiment. 
         FIG. 7  is a top plan view corresponding to  FIG. 2  of an alternative embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows part of a sorting device  1  according to a first preferred embodiment of the invention. The sorting device  1  comprises a chain  2 . The chain  2  comprises links  3 , which are pivotally connected about vertical pivot axles  4 . A guide wheel  5  is provided for each link  3 , the central axis of which guide wheel coincides with that of an associated pivot axles  4 . The guide wheels  5  run in a U-shaped guide (not shown), which extends in an endless conveying path. Provided at the upper side of each link  3  is furthermore a transversely oriented supporting arm  6 , with running wheels  7  mounted to two opposite ends thereof, the central axes of which running wheels are oriented transversely to the conveying direction  9  of the sorting device  1  and in line with each other. The running wheels  7  run on rails (not shown), which extend parallel to the conveying path defined by the U-shaped guides the guide wheels  5 . 
     Furthermore, a load carrying platform  10  is provided for each link. The successive load carrying platforms are in line with each other. Each load carrying platform  10  is more or less moon-shaped. The circumference thereof is defined by two at least substantially straight side edges  11 , an arcuate front edge  12  and a likewise arcuate rear edge  13 . The edges  12 ,  13  have an angle of arc of about 95 degrees. Generally, said angle of arc preferably ranges between 70 and 120 degrees. At the tips  14  of the moon shape, each load carrying platform  10  is rigidly connected to a supporting arm  6  disposed thereunder, whilst each load carrying platform  10  is supported at the location of the main surface  15  by a supporting arm  6  associated with a next link  3 , which is located in front thereof, without being connected to said supporting arm  6 , so that relative movement between the load carrying platform  10  and the respective next supporting arm  6  is possible. 
     The radii of curvature of the front edge  12  and the rear page  13  correspond, so that the arcuate shape of the front edge of a load carrying platform matches the arcuate shape of the rear edge of a next load carrying platform  10  located at the front of the load carrying platform  10  in question. The successive load carrying platforms  10  thus form an at least substantially closed surface, or, in other words, a closed deck. This closed nature is maintained when passing through bends in the conveying path, as is shown on the right-hand side in  FIG. 3   a . Upon passing through a bend, each load carrying platform  10  moves over the supporting arm  6  disposed thereunder at the location of its main surface  15 . The load carrying platforms  10  and the links  3  are so dimensioned and positioned relative to each other that the central axes of the radii of curvature of abutting front edges  12  and rear edges  13  coincide with a pivot axle  4 , as is shown in particular in  FIG. 3   a.    
     In order to make it possible to push a product to be sorted, which is supported by one or a number of load carrying platforms  10 , off the load carrying platforms, the sorting device  1  further comprises a pusher beam  21  for every three load carrying platforms  10 . The load carrying platforms  10  provided at opposite ends of the pusher beam  21  are provided with a through slot  22 , unlike the load carrying platforms  10  located therebetween, which slot is oriented transversely to the conveying direction  9 . The slot  22  extends over substantially the entire width (this is the dimension of each load carrying platform  10 , seen in a direction perpendicular to the conveying direction  9 ) of the associated load carrying platform  10 . In an alternative embodiment, each load carrying platform might consist of two parts defining a through slot, such as the slot  22 , between them, which two parts are interconnected at the ends of the slot. 
     Via the slots  22  and vertical pivot axles  16 , each pusher beam  21  is pivotally connected, about the vertical pivot axles  16 , to a guide member disposed under the associated load carrying platform  10 , more specifically to a front guide member  23  and a rear guide member  24  (see  FIG. 2 ). Said guide members  23 ,  24  are arranged for cooperation with a guide system which is provided under the load carrying platforms  10 . For a more detailed description of said guide members  23 ,  24  and the guide system, reference is made to Dutch patent application NL 1034156, the entire contents and disclosure of which are incorporated by reference herein. 
     Each guide member  23 ,  24  comprises two guide wheels  25 ,  26 , which are arranged side by side in pairs, a limited distance apart. The guide system under the load carrying platforms  10  comprises parallel rails  27 ,  28  near the longitudinal sides of the load carrying platforms  10 , which rails  27 ,  28  extend parallel to the conveying direction. 
     During normal use, when no sorting action is taking place, one of the rails  27 ,  28  extends between the wheels  25 ,  26  of the guide member  23 ,  24 , so that the guide member  23 ,  24 , and thus the associated pusher beam  21 , will move along the respective rails  27 ,  28 . The rails  27 ,  28  are interrupted at a sorting location  30 , at the location indicated by reference numerals  31 ,  32 , so as to enable the guide members  23 ,  24  to become detached from the respective rails  27 ,  28  during a sorting action. In the example shown in  FIG. 2 , the sorting location is arranged for pushing a product present on the load carrying platforms  10  beside a pusher beam  21 , which (initially) extends above the rail  27 , in the direction of the rail  28 . A sorting guide system  33  extends between the interruptions  31 ,  32 , which system is likewise described in the aforesaid Dutch patent application NL 1034156. 
     It is furthermore noted that the sorting guide system  33  is interrupted halfway its length, at the location indicated at  34 , so as to enable the chain  2  to pass the sorting guide system  33 . It is furthermore worth mentioning that a switch  35  is provided in the rail  27  at the location of the interruption  31 , which switch can pivot forward and backward between two positions about a vertical pivot axle  36 . In the position shown in  FIG. 2 , the switch  35  will force the guide members  23 ,  24  in the direction of the sorting guide system  33 , causing the associated pusher beam  21  to cross from the side of the rail  27  to the side of the rail  28  and push a product adjacent thereto on the load carrying platforms  10  off said platforms during said transverse movement. At the location of the interruption  32 , the guide members  23 ,  24  will resume their cooperation with the rail  28  again. In the position of the switch  35  that is illustrated in dotted lines, the pusher beam  21  will continue to follow the rail  27  past the switch  35  as well. 
     As shown in  FIG. 3   a , the pusher beam  21  is telescopic, so that its length can change. This is necessary not only during the above-described sorting action when the spacing between two through slots  22  associated with a pusher beam  21  remains unchanged, but the length of the pusher beam  21  needs to change, because of the oblique orientation thereof between the slots  22 , if the guide members  23 ,  24  are spaced by a fixed distance from the ends of the pusher beam  21 . Alternatively, it would also be possible to use a pusher beam  21  having a fixed length, in which case the pusher beam  21  could be slidably connected to one or both of the guide members  23 ,  24 . The telescopic nature of the pusher beam  21  is also advantageous when passing through bends, as the spacing between the adjacent slots associated with a pusher beam  21  will change during said movement. For example, in the inside bend, said spacing will decrease, whereas said spacing will increase in the outside bend. This is shown in  FIG. 3   a.    
       FIG. 4  shows a second preferred embodiment of a sorting device  41  according to the invention, which is very similar to the device  1  as described in the foregoing. The sorting device  41  comprises load carrying platforms  42 , which correspond to the load carrying platforms  10  of the sorting device  1 , at least insofar as slots  22  are present in said load carrying platforms  10 . Each of the load carrying platforms  42  of the sorting device  41  has a slot  43  that is quite similar to the slots  22 . The sorting device  41  uses a chain, such as the chain  2 , with supporting arms, such as the supporting arms  6 , for driving the load carrying platforms  42  in the conveying direction  44 . Furthermore, a guide system is provided under the load carrying platforms  42 , which guide system is quite similar to the guide system used in the sorting device  1 , i.e. comprising rails, such as the rails  27 ,  28 , and a sorting guide system, such as the sorting guide system  33 . 
     The main difference between the sorting device  41  and the sorting device  1  is the length of the pusher beams  45 , which is significantly less than the length of the pusher beam  21 . The fact is that the length of the pusher beams  45  is nearly the same as the pitch distance of the links  3  disposed thereunder or, in other words, of the associated load carrying platforms  42 . 
     Only one guide member is provided for each pusher beam  45  under the associated load carrying platform  42 , which guide member is similar to one of the guide members  23 ,  24  of the sorting device  1 . The guide member in question (not shown) is rigidly connected to the associated pusher beam  45 . Although it is possible in the sorting device  1  to push products off the common supporting surface defined by the load carrying platforms  42  by means of a single pusher beam  45 , the sorting device  41  is in particular suitable for pushing a product to be sorted off the load carrying platforms by means of a number of pusher beams  45  in a manner similar to the manner in which a number of pusher shoes simultaneously push products off the supporting surface in the aforesaid prior art POSISORTER. 
     In this embodiment, the ends of the pusher beams  45  are pointed, with inclined flanks  46 , which define a joint pushing surface  47  (indicated by a dashed line), at least during movement of the pusher beams  45  transversely to the conveying direction  44 . In addition to that, the pointed shape has the advantage that the points of adjacent pusher beams  45  will be positioned beside each other in an inside bend, as shown in  FIG. 5 , thus giving each other sufficient space, in spite of the length of the pusher beams. 
       FIGS. 6   a  and  6   b  show the gap  51  that is present between two successive load carrying platforms  42  at the location of the front edge  12  and the rear edge  13  thereof. In principle said gap  51  involves a risk that objects, such as a buckle, for example, will get jammed therebetween, which may interfere with such a product being pushed off the load carrying platforms  42 . Said risk is limited precisely because of the arcuate shape of the gap  51 , to be true, but said risk can be further reduced by having the successive load carrying platforms  42  (or the load carrying platforms  10  in the sorting device  1 ) overlap at the location of the respective edges, which to that end have a complementary stepped configuration or which alternatively, as shown in  FIG. 6   b , have a parallel inclined configuration. 
     According to another alternative embodiment, a closing or aligning element, such as the arcuate strip  61 , for example made of plastic or stainless steel, is used between two successive load carrying platforms  42 , which strip in any case extends with a limited amount of vertical clearance within aligned, facing grooves  62  in the facing short sides of the respective load carrying platforms  42 , which are for example made of wood. The function of the strip  61  is twofold, viz. preventing objects getting between the load carrying platforms  42  and aligning the two load carrying platforms relative to each other. In the present example, the grooves  62  are formed in the short sides, but alternatively they could also be created under the load carrying platforms by making use of curved angle sections, such as the angle section  63 , which is connected to the underside of a load carrying platform  42 , as is shown by way of illustration in dotted lines only for the left-hand load carrying platform  42  in  FIG. 6   c , as a result of which the groove  64  could be formed. The strip  61  can be pushed into the grooves  64  from the side of the load carrying platforms  42 . Advantageously, the strips  61  are retained in the grooves  64  at their ends. Those skilled in the art will appreciate that the strips  61  do not impede the pivoting movement relative to each other. 
     The scope of the invention is not limited to the preferred embodiments described in the foregoing, but it is in the first place determined by the appended claims. 
     As an alternative to the use of a guide system disposed under the load carrying platforms, it is also possible, for example, to use one or two driving motors  70  for each pusher beam, as shown in  FIG. 7 . The driving motors  70  being connected to one or two load carrying platforms. For further explanation, reference is made to Dutch patent application NL 1034940, the entire contents and disclosure of which are incorporated by reference herein. When using elongated pusher beams, such as the pusher beam  21 , with a guide member, such as the guide members  23 ,  24 , at both ends, it may furthermore be decided by way of alternative to use two parallel, stationary guides for each sorting location, in which guides the respective guide members can move simultaneously and the pusher beam crosses from one longitudinal side to the other longitudinal side with its longitudinal direction parallel to the conveying direction, as is for example described in Dutch patent application NL 1033313, the entire contents and disclosure of which are incorporated by reference herein. Furthermore it might be decided to provide the two through slots, such as the slots  22 , associated with elongated pusher beams, such as the pusher beam  21 , in one and the same load carrying platform. In the latter case it is as a rule desirable to make the load carrying platforms longer.