Abstract:
The invention relates to a conveyor part, having a conveyor track, wherein the conveyor track comprises at least one rotary moulded conveyor track structure. The invention further relates to a method of manufacturing a conveyor part comprising the following steps, to be performed in any suitable order: providing a rotary mould having a cavity shaped as the outside of a conveyor portions, adding a thermoplastic or resinous material inside the mould, rotating the mould under gradually heating the mould, allowing the thermoplastic material to melt and to cover the inner walls of the mould or allowing the resinous material to cure on the inner walls of the mould, allowing the mould to cool, opening the mould to remove the conveyor part.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the United States national phase of International Application No. PCT/NL2014/050039 filed Jan. 24, 2014, and claims priority to Netherlands Patent Application No. 2010186 filed Jan. 25, 2013, the disclosures of which are hereby incorporated in their entirety by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a conveyor. 
     More specifically, the invention relates to more flexible and less expensive conveyor systems and to a method of their manufacture. 
     Description of Related Art 
     In the art, conveyor systems are widely used. Mostly a conveyor comprises some basic components: a support frame, a chain or belt track, a belt or chain, a drive system end and a belt or chain return end. 
     In the art the conveyor track is manufactured of metal parts e.g. extruded aluminium elements, which are bolted or welded together. This provides a sturdy, yet rather heavy and inflexible conveyor system. For less demanding applications and higher flexibility, e.g. when product pathways are changed frequently, conveyors of the art are less suitable. Furthermore, they are more cumbersome to disassemble and reassemble. Accordingly it is an object of the invention to mitigate or solve the above described and/or other problems of belt and chain link conveyors in the art, while maintaining and/or improving the advantages thereof. 
     More specifically the object of the invention can be seen in improving the flexibility of belt and chain link conveyors while reducing the cost of manufacture of the same. 
     SUMMARY OF THE INVENTION 
     These and/or other objects are reached by a conveyor part, suitable for a belt or chain conveyor, having a conveyor track portion, wherein the conveyor track portion comprises at least one rotary moulded conveyor track structure. This can provide a more cost effective manufacturing technique, which can produce portions which can very flexibly be applied. Furthermore conveyors made of these parts are relative light and versatile in application. The inner space of the rotary moulded structure can be hollow. Thus a light weight sturdy elements can be produced that comprise a relative low amount of construction material and can be more easily connected. For instance customised track portions can be sawn at any desired length and yet be connected to other track parts. The conveyor track can comprise a central guiding slit. In this guiding slit, rollers, mounted on the belt or the conveyor links can be guided. Thus wear at the side walls of the track and enhanced friction may be reduced. For straight portions, the central guiding slit may be omitted, whereas in curved portions, application can be advantageous. The conveyor part may comprise slide bar connectors. The slide bars can provide additional strength and can avoid wear of the support surface of the conveyor track. The slide bar connectors may be longitudinal slits. At least one abutting end of the track portion can be provided with a first connector. Thus the track parts can be interconnected, rendering the system flexible and versatile similar to a toy train track. A second abutting end can similarly be provided with a second connector. The first and/or the second connector can of the male or of the female type. The female type connector can comprise a male connector receiving space for a tight fit. By a close fit, the separate parts can be prevented from moving relative to each other. Thus wear and hook ups of a track or belt can be prevented and a smooth ride of the belt or chain can be improved. In a dedicated part, the first abutting end opposing second end can comprise a shaft or axle, configured to guide a belt or a chain return. The shaft can be connected to a drive, e.g. an electric motor eventually provided with a gear. Thus a chain or belt conveyor can be assembled comprising at least an intermediate conveyor portion, a return end conveyor part and drive end conveyor part. Thus the two return ends can allow a transport flight and a return flight of the conveyor belt or chain to run as a closed loop over the conveyor assembled from the separate portions. In this conveyor the return axle can be configured to run idle. Alternatively on both ends of a completed track, two drive units can be placed. This arrangement can be applied e.g. for a better transport of the return part of the conveyor chain or conveyor belt. 
     A further aspect of the invention is a method of manufacturing a conveyor portion comprising the following steps, to be performed in any suitable order: providing a rotary mould having a cavity shaped as the outside of any of the herein above described parts, adding a thermoplastic or resinous material inside the mould, rotating the mould under gradually heating the mould, allowing the thermoplastic material to melt and to cover the inner walls of the mould or allowing the resinous material to cure on the inner walls of the mould, allowing the mould to cool, opening the mould to remove the conveyor portion. Thus flexible and cost effective conveyor parts can be manufactured. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to further elucidate the invention, exemplary embodiments will be described with reference to the drawing. In the drawing: 
         FIG. 1  depicts a first schematic perspective view of a conveyor track portion according to an embodiment of the invention; 
         FIG. 2  depicts a schematic perspective view of a track portion according to second embodiment of the invention; 
         FIG. 3  depicts a schematic perspective view of a number of track portions according to a third embodiment of the invention; 
         FIG. 4  depicts a schematic perspective view of two track portions according to a fourth embodiment of the invention; 
         FIG. 5  depicts a schematic perspective view of series of three track portions according to a fifth embodiment of the invention; 
         FIG. 6  depicts a schematic perspective view of a conveyor track part with a series of interconnected chain links according to a sixth embodiment of the invention; 
         FIG. 7  depicts a schematic perspective view from underneath of the track part as shown in  FIG. 6 ; 
         FIG. 8  depicts a schematic perspective view of a track part according to  FIG. 6  with a conveyor belt according to another embodiment of the invention; 
         FIG. 9  depicts a schematic cut open view of a track portion according to a further embodiment of the invention; 
         FIG. 10  depicts a schematic cross section of a track portion according to an alternative embodiment of the invention; 
         FIG. 11  depicts a schematic cross section of a track portion according to a further embodiment of the invention; 
         FIG. 12  depicts a schematic side view of a guiding element for a track portion as depicted in  FIG. 11  according to another embodiment of the invention; 
         FIG. 13  depicts a schematic perspective view of a drive and a track portion according to yet another embodiment of the invention; 
         FIG. 14  depicts a schematic cross sectional view of a track portion according to a further embodiment of the invention; 
         FIG. 15  depicts a schematic cross sectional view of a track portion connector suitable for the track portion according to  FIG. 14 ; 
         FIG. 16  depicts a schematic perspective view of a connection between two track portion according to a further embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The figures represent specific exemplary embodiments of the inventions and should not be considered limiting the invention in any way or form. Throughout the description and the figures the same or corresponding reference numerals are used for the same or corresponding elements. 
     The expression “longitudinal” used herein is to be understood as, though not to be considered limited to the direction similar to the direction of motion of the belt or conveyor chain links within the conveyor track. 
     The expression “abutting end or abutting surface” used herein is to be understood as, though not to be considered limited to the ends of the conveyor track portion, where the track portion is connected to another track portion. 
     The expression “female or female connector of a track portion” used herein is to be understood as, though not to be considered limited to a connector configured to have an open structure able and suitable for accepting a male connector of a track portion to fit in, preferably such that both portions are aligned and form a continuous combined track when connected. 
     The expression “track or track portion” used herein is to be understood as, though not limited to a piece or a portion of a conveyor structure, on which a conveyor belt and/or a chain conveyor can move, wherein the conveyor belt or chain is guided or supported by the track or the track portion. 
     In  FIG. 1 , a schematic image is presented of a first track portion  1  of a conveyor. The portion  1  comprises a guiding surface  2 , on which a conveyor belt or conveyor links can move and be supported. The guiding surface can comprise two slits  3 , in which guiding bars may be inserted. These guiding bars can be made out of a durable, low resistance material, in order to reduce friction and/or prevent the surface  2  from wearing off by the belt or links moving over it. Typical material for the guiding bars can be nylons or POM. Other materials with similar qualities may be employed as well. 
     The guiding surface  2  further is equipped with a central guiding channel  17 , provided with sidewalls  6 . The side walls  6  are configured to be able to guide rollers or other guiders that can be centrally mounted on the belt or the conveyor links, as is presented in  FIGS. 6 and 7 . 
     The side walls  6  can position the belt or chain in the centre of the track portion  1  and can prevent the side of the belt or conveyor links from touching side walls  15 . Thus, the side walls  15  can be protected against excessive wear and friction between the moving belt or chain and the track can be reduced. 
     The track can be manufactured such that the upper side is symmetrical with the lower side, such that the surface  4  can act as a support surface for a belt or conveyor chain, ones the track portion  1  is turned upside down. In that case side walls  7  of central guiding channel  18  will guide the belt or chain. In this position, the guiding bars can be mounted in the slits  5  instead of in slits  3 . The advantage of this symmetry between upper and lower side is that one track portion can serve both as a left hand and as a right hand curve. This renders the system even more flexible and versatile. 
     On a first abutting side, the track portion  1  is provided with a circumferential rim  8 , enclosing a female connection space  10 . The space  10  is in a longitudinal direction seen, located more inside the track portion  1 , bordered by a surface  9 . The surface  9  can provide the track portion  1  with additional strength. 
     The complete track portion  1  as depicted in  FIG. 1  can be manufactured by rotation moulding. This technique is suitable for making hollow parts, such that material is saved from being used. The track portion  1  can be provided with so called kissing points or kissing surfaces, as is depicted in  FIG. 8  and described in more detail herein below. 
       FIG. 2  depicts a short track portion  1 A having two male connectors  19  and  20  at its abutting sides. The male connector  19  is having an abutting surface  22 , which could face the surface  9  of the track portion  1  when the male connector  19  or  20  is entered in the female connector  10  of the track portion  1 . 
     Between the two male connectors  19  and  20 , a rim  21  can be provided. The rim  21  can prevent a too deep insertion of the connector  19  in a female connector. In use with the track portion  1 , the abutting surface  24  of the rim  21  can face the abutting surface  14  of the rim  8  of the track portion  1 . The circumferential surface of the rim  21  can in use be part of the track. 
     Track portions  1 ,  1 A  26 ,  27 ,  28 ,  35 ,  36  and  37  can be made at e.g. a series of standard lengths and standard curve portions. A number of radii and a angles in 15 degrees or a multiple thereof may be well suited. The portions  26  and  27  in  FIG. 3  are of the same length, whereas the portion  28  is e.g. about one fifth of the length of portion  27 . The portions  35  and  36  both are of an angle of 30 degrees, as is the portion  37 , which is virtually the same as the portions  35  and  36 , except that the portion  37  is turned upside down, such that the curvature of portion  37  is inverted to the curvatures of curve  35  and  36 . By making the upper and lower side symmetrical, additional flexibility can thus be provided for. Further the portions  26 ,  27 ,  28   35 ,  36  and  37  in  FIG. 3  all are provided with a female  30 ,  32  and a male  29 ,  31  connector. All parts may very well be provided with only one species of connector, or even the portions may be sawn to the desired length, after which e.g. the portion  1 A with the two male connectors  19  and  20  can be inserted in the sawn through, open abutting end of the thus customised track portion. 
       FIG. 4  depicts a dedicated track portion and a curved portion  38 . The dedicated track portion is a drive end portion  40 , which can be provided with two brackets  45  and  46  holding an axle  44 . The axle  44  can be borne in bearings, and is connected to a gear  43 . The gear  43  on its turn is connected to a drive shaft of a motor  41 . Attached to the axle are sprocket wheels  47 ,  48 ,  49  and  50  of which teeth (not shown) can grab into apertures of a belt or spaces between or within links of a conveyor chain. The drive end portion  40  is provided with a male connector  51 , which as can be seen in  FIG. 4 , fits into e.g. the female connector  39  of the curved track portion  38 . The portion  38  is on its turn on the other abutting side provided with a male connector  52 . 
       FIG. 5  depicts in detail another track end portion, being a return end  51 . The return end is provided with two brackets  59  and  60  holding an axle  54 . Again the axle  54  can be borne by bearings within the brackets  59  and  60 . The axle is provided with a set of idler sprockets or guiding wheels  55 ,  56 ,  57  and  58 . The axle  54  may be allowed to move in a longitudinal direction, such that a tensioner  61  can be applied in order to adjust the length of the track and thus the tension and play of the belt or conveyor chain. 
     In  FIG. 5 , the return track portion  51  is provided with a female connector  53 , in which the male connector  52  fits. Once the return track portion  51  and the drive end portion  40  are fitted to the curved track portion  38 , a curved conveyor track is completed, such that a chain or a belt can be installed. Thus a remarkably simple system is provided, with a excellent flexibility in extending, adjusting or modifying the tracks. 
     In order to support the track at a certain height, a support structure can be installed, as is depicted in  FIG. 6  and  FIG. 7 . In these figures, the track portion  26  is on its sides provided with mounting slits  33  and  34 . In the mounting slits, mounting connectors  73  can be placed to which brackets  74  can be connected. The brackets are connected to uprights  67  and  68  which can be provided with support plates  69 . The uprights  67  and  68  are interconnected with a beam  71 , such that a sturdy support can be given. A set of uprights  68  and  69  and the connectors  73  can be moved longitudinally through the slits  33  and  34  along the track portion  26 , such that the supports can be very flexibly altered and customised. 
     In between the uprights  67  and  68 , support rollers  72  may be installed, which can guide the return part of the conveyor belt or the conveyor chains is depicted in  FIGS. 6 and 7 , a portion of a chain link conveyor is depicted. The chain link conveyor comprises interlocking links  62 , which are rotably interconnected by means of pins  63 , allowing the links to rotate relative to each other in the two axes perpendicular to the longitudinal direction of the track. In vertical sense, the links of the transport part of the conveyor are supported by guiding rods  65  and  66 , which are inserted in the slots  3  and  5  within the support surface  2 . In horizontal sense, perpendicular to the longitudinal direction of the track  26 , the links  62  are guided by roller  64 , which is centrally mounted to the or some of the links  62 . The roller  64  can roll against the side walls  6  of the central guide channel  17 , which can be seen in  FIG. 7 . 
     Alternatively, instead of a chain link conveyor, in all embodiments shown also a cloth, a metal knitted or any other suitable conveyor belt can be applied, as is schematically shown in  FIG. 8 . In this figure, the conveyor belt  107  rests on the guiding bars  65  and  66 . A further guiding bar may be placed in the central guiding slit  17 , such that more support is given to the belt  107 . 
     Alternatively or additionally, in mounting slits  33  and  34 , guides and chicanes for manipulating the articles to be transported on the conveyor can be installed. 
     In order to provide the track portions with additional strength, kissing points  75  and  76  can be applied, as is shown schematically in  FIG. 9 . In this figure the surface  2  is connected to the opposing surface  4 , such that a more sturdy track portion can be obtained. 
     In  FIG. 10  a cross sectional view of an alternative track portion is depicted. In this figure, a conveyor chain link  62  is provided with a guiding hook  77 , which engages with its finger  78  in a guiding slit  79 . Thus the conveyor link  62  can be held down on the track portion. Further the track portion is similar to the portions in  FIGS. 6 and 7  provided with a central guiding slit  6 , in which a guiding roller  64  can fit. The broken line  80  can represent an line of symmetry, in which case the lower side is the same as the top side of the track portion. Below the line  80 , the track portion can also be provided with any other suitable form. 
     On the lateral side of the track portion as represented in  FIG. 10 , protectors  81  can be mounted. These protectors  81  can similar to track portions be manufactured by rotary moulding. The protector  81  can have a rim  82  which can extend over the chain link  62  such that the chain link  62  is well engaged in the track portion and can be prevented from moving upward. 
     In  FIG. 11  a schematic cross sectional view of an alternative track portion is presented. In this track portion, kissing points  75  are arranged between the inner facing walls of the guide slits  3  and  5  instead as in between the support surfaces  2  and  4  as is depicted in  FIG. 9 . Any combination of these kissing points may be applied as well like e.g. alternating in a direction along the track between the surfaces  2  and  4  and the slits  3  and  5 . In this figure, the conveyor links  62  extend sideward beyond the width of the track portion. A protector  82  is mounted on the side of the track portion and the edge  83  engages the lateral ends of the links  62 , such that the links  62  are not allowed to move upward and are kept on track. The protector  82  can be manufactured by rotation moulding as well. 
     In  FIG. 12  a side view of the protector  82  is presented, where a marking  86  can be provided. In  FIG. 12  the marking indicates the direction of motion of the belt, though other information can be provided as well. These markings can be made e.g. in relief inside the rotation mould. 
     In  FIG. 13  an alternative connection for a drive unit  94  is presented. The drive unit  94  comprises a motor  41 , a gear  43  and a drive shaft  44 . On the drive shaft, sprocket wheels  47 ,  48 ,  49  and  50  are installed for transferring the rotation of the shaft  44  into a motion of a belt or conveyor chain. The drive unit  94  comprises two side panels  90  and  91 , which are interconnected by means of a cross bar  89 . The side panels  90  and  91  hold the axle  44  in place e.g. by bearings (not shown). On the cross bar  89  two inserts  87  and  88  are mounted. On a first abutting end, these inserts  87  and  88  fit inside the guiding slits  3  of the track portion  93  and on the first end opposing second end they extend beyond the perimeter of the sprocket wheels  48  and  49 . In this way a conveyor belt or a conveyor chain can be neatly guided onto the sprocket wheels, without building a pocket. 
     The side panels  90  and  91  are further provided with inserts  92 , which fit into the mounting slits  33  and  34 . The cooperation between the inserts  88 ,  89  and  92  on the one hand and the slits  3 ,  33  and  34  on the other provides a sturdy, yet in longitudinal direction adjustable connection between the track portion  93  and the drive unit  94 . In the herein above described figures, most inner corners of the rotation moulded components are depicted as well defined sharp 90 degree corners. Since these components are however manufactured by rotation moulding, the corners tend to cool down quicker than it adjacent surfaces during the cooling phase. Thus in general in the corners and inner edges  95 ,  96  and  97 , more material solidifies during cooling, such that these corners contain more material and are substantially rounded on the inner side. 
     This effect is depicted in the schematic cross sectional view of  FIG. 14 . In order to obtain a well-fitting system, the outer corners of the male connectors may be skewed, as is depicted in  FIG. 15 . Here the corners  99 ,  100 , and  101  are provided with substantially slightly skewed surfaces, in order to be able to provide a good fit. 
     Finally in  FIG. 16 , an alternative connection is shown. The each other facing abutting ends of two track portions  102  and  103  are respectively provided with integrated material fill-ups  104  and  105  in the respective mounting slits  33  and  34 . The fill-ups  104  and  105  are provided with a through bore, through which a bolt  106  can be inserted. By means of the bolt, the portions  102  and  103  can be mutually secured. Though not shown, yet again also a male and female connector may be present with this connection technique. 
     The invention is to be understood not to be limited to the exemplary embodiments shown in the figures and described in the specification. For instance the connection between the portions can be performed in different ways such as by means of jig saw type of male and female connectors or any other kind of connector. The straight track portions may alternatively be manufactured by means of die extrusion. The kissing point are as an example provided between surface  2  and  4 , any alternative installation of kissing points may be applied. For sound absorbing reasons and/or for further strength, portions may be filled up or partially filled up with a curable foam, such as poly urethane foam. 
     These and other modifications are considered to be variations that are part of the framework, the spirit and the scope of the invention outlined in the claims. 
     LIST OF REFERENCE SIGNS 
     
         
           1 . Conveyor track portion 
           2 . Guiding surface 
           3 . Slit 
           4 . Guiding surface 
           6 . Side wall 
           7 . Side wall 
           8 . Rim 
           9 . Abutting surface 
           10 . Female connector 
           11 . Side wall 
           12 . Side wall 
           13 . Upper wall 
           14 . Lower wall 
           15 . Guiding wall 
           16 . Guiding wall 
           17 . Central guiding channel 
           18 . Central guiding channel 
           19 . First masculine connector 
           20 . Second masculine connector 
           21 . Rim 
           22 . Abutting surface 
           23 . Abutting surface 
           24 . Rim side edge 
           25 . Rim side edge 
           26 . Conveyor track portion 
           27 . Conveyor track portion 
           28 . Conveyor track portion 
           29 . Male connector 
           30 . Female connector 
           31 . Male connector 
           32 . Female connector 
           33 . slit 
           34 . slit 
           35 . Curved conveyor track portion 
           36 . Curved conveyor track portion 
           37 . Curved conveyor track portion 
           38 . Curved conveyor track portion 
           39 . female connector 
           40 . drive portion end 
           41 . Motor 
           42 . Support 
           43 . Gear 
           44 . drive axle 
           45 . Axle bracket 
           46 . Axle bracket 
           47 . Sprocket wheel 
           48 . Sprocket wheel 
           49 . Sprocket wheel 
           50 . Sprocket wheel 
           51 . Return end 
           52 . Male connector 
           53 . female connector 
           54 . Return axle 
           55 . Guide wheel 
           56 . Guide wheel 
           57 . Guide wheel 
           58 . Guide wheel 
           59 . Axle bracket 
           60 . Axle bracket 
           61 . Belt or chain tensioner 
           62 . Link 
           63 . pin 
           64 . roller 
           65 . guiding rod 
           66 . Guiding rod 
           67 . Upright 
           68 . Upright 
           69 . plate 
           70 . plate 
           71 . beam 
           72 . Roll 
           73 . Connector 
           74 . Bracket 
           75 . Kissing point 
           76 . Kissing point 
           77 . Guiding hook 
           78 . Finger 
           79 . Guiding slit 
           80 . Symmetry line 
           81 . Protector 
           82 . Edge 
           83 . Edge 
           84 . Edge 
           85 . Symmetry line 
           86 . Marking 
           87 . Insert 
           88 . Insert 
           89 . Cross bar 
           90 . Side panel 
           91 . Side panel 
           92 . Insert 
           93 . Track portion 
           94 . Track portion 
           96 . Inner corner 
           97 . Inner corner 
           98 . Inner corner 
           99 . Skewed surface 
           100 . Skewed surface 
           101 . Skewed surface 
           102 . Track portion 
           103 . Track portion 
           104 . Fill up 
           105 . Fill up 
           106 . Bolt 
           107 . Conveyor belt