Abstract:
The present invention provides a rail conveyor system of the type having a rail track ( 9 ) including a delivery run ( 1 ) extending between a loading end ( 5 ) and a discharge end ( 6 ) and a return run ( 12 ) extending from the discharge end ( 6 ) to the loading end ( 5 ), a plurality of carriages ( 8 ) spaced apart from one another and arranged to run on wheels ( 24 ) supported by the track ( 9 ), and a continuous carry belt ( 10 ) supported by the carriages ( 8 ); wherein, at least at the discharge end ( 6 ), the carriages ( 8 ) are turned around to return to the loading end ( 5 ) by being entrained around only one or more vertical turnover wheels ( 7 ) arranged such that the carriages ( 7 ) are delivered to the return run ( 12 ) beneath the delivery run ( 1 ).

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to a Rail Conveyor System with Vertical Carriage Return and has been devised particularly though not solely for use in situations requiring a narrow footprint at the head and/or tail end of the system. 
       BACKGROUND OF THE INVENTION 
       [0002]    The following discussion of the prior art is intended to present the invention in an appropriate technical context and allow its advantages to be properly appreciated. Unless clearly indicated to the contrary, however, reference to any prior art in this specification should not be construed as an express or implied admission that such art is widely known or forms part of common general knowledge in the field. 
         [0003]    There are many advantages to rail conveyor technology for the long distance transportation of bulk materials as is set out in our International patent application PCT/AU2011/000930 published as WO2012/009765A1, the content of which is incorporated herein by way of cross-reference. 
         [0004]    In the rail conveyor system as described in our earlier PCT application, the carriages are typically turned around at both the head and tail end of the system on a horizontal rail loop as shown in  FIG. 1  of the present application. This has the advantage of being simple and direct, and is suitable for situations where there is adequate room to accommodate the width of the rail loops. 
         [0005]    There are however many situations where space is limited at either or both of the head and tail end of the conveyor system and where it is necessary to redirect the carriages from the delivery run to the return run using only a narrow footprint. 
         [0006]    Even the turnaround configuration shown in FIG. 4 of PCT/AU2011/000930 has a significant width of approximately 5-6 metres due to the necessity to position the delivery run and the return run side by side and to re-orientate the carriages using a horizontal turnaround wheel. This wide footprint is not suitable in many delivery situations. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention therefore provides a rail conveyor system of the type having a rail track including a delivery run extending between a loading end and a discharge end and a return run extending from the discharge end to the loading end, a plurality of carriages spaced apart from one another and arranged to run on wheels supported by the track, and a continuous carry belt supported by the carriages; 
         [0008]    wherein, at least at the discharge end, the carriages are turned around to return to the loading end by being entrained around only one or more vertical turnover wheels arranged such that the carriages are delivered to the return run beneath the delivery run. 
         [0009]    Preferably, there is a single vertical turnover wheel, with the delivery run, the turnover wheel, and the return run being located in the same vertical plane at the discharge end. 
         [0010]    Preferably, at the loading end, the carriages are turned around to return to the discharge end by being entrained around only one or more vertical turnover wheels arranged such that the carriages are delivered to the delivery run above the return run. More preferably, there is a single vertical turnover wheel, with the delivery run, the turnover wheel, and the return run being located in the same vertical plane at the loading end. 
         [0011]    In one form of the invention the carriages in the return run are rotated through 180° about an axis in or parallel to the return run after leaving the turnover wheel, such that the carriages are returned in an upright orientation. 
         [0012]    Preferably, the carriages are designed to accommodate flexing while being rotated. 
         [0013]    In one form the flexibility is achieved by providing compressible blocks as mountings between supports for the wheels and supports for the carry belt. 
         [0014]    In another form the flexibility is achieved by mounting the wheels on leaf springs attached to the carriage. 
         [0015]    In a further form of the invention the carriages are designed to travel the return run in an inverted position and are provided with means to support the carry belt in the inverted position. 
         [0016]    In one embodiment the means to support the carry belt in the inverted position include pads protruding upwardly from the carriage when in the inverted position. 
         [0017]    In an alternative embodiment, the means to support the carry belt in the inverted position include bars arranged to support the carry belt in a load carrying manner such that bulk material can be conveyed on both the delivery run and the return run. 
         [0018]    Preferably, the carriages are interconnected and spaced apart by a rope and wherein the rope is tensioned by horizontal movement of the turnover wheel. 
         [0019]    Preferably, the rope passes through a hole in a bush in each carriage and the rope is provided with a stop, larger in width than the hole in the bush, adjacent each carriage such that each carriage can move relative to the rope, up to and away from the stop, to accommodate relative differences in stretch between the carry belt and the rope. 
         [0020]    Preferably, a compression spring is provided for each carriage, wound around the rope and arranged to act as a buffer between the bush and the stop. 
         [0021]    Alternatively, the carriages are preferably fixed to the rope by means of a mechanical fastener. In one form, the mechanical fastener is a quick action fastener designed for quick release of the carriages from the rope. This enables reduce time required for maintenance of the carriages and/or rope. 
         [0022]    Preferably, the rope is a wire rope. Alternatively, the rope is made of nylon or polyester. 
         [0023]    Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. 
         [0024]    Furthermore, as used herein and unless otherwise specified, the use of the ordinal adjectives “first”, “second”, “third”, etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    Notwithstanding any other forms that may fall within its scope, one preferred form of the invention, and variations thereof, will now be described with reference to the accompanying drawings in which: 
           [0026]      FIG. 1  is a perspective view of a prior art rail conveyor system utilising horizontal turnaround loops at each end; 
           [0027]      FIG. 2  is a similar view to  FIG. 1  showing the vertical carriage return system according to the invention at either end of the conveyor; 
           [0028]      FIG. 3  is a perspective view to an enlarged scale of the delivery end of the conveyor shown in  FIG. 2  wherein the carriages are returned to an upright position after passing over the turnaround wheel; 
           [0029]      FIG. 4  is a diagrammatic perspective view of a flexible carriage using rubber pads; 
           [0030]      FIG. 5  is an enlarged view of a portion of  FIG. 4 ; 
           [0031]      FIG. 6  is a perspective view of an alternative form of flexible carriage using leaf springs; 
           [0032]      FIG. 7  is an enlarged view of a portion of  FIG. 6 ; 
           [0033]      FIG. 8  is a cross-sectional elevation through the delivery run and return run of an alternative embodiment of the invention wherein carriages are returned in an inverted position; 
           [0034]      FIG. 9  is a perspective view of the configuration shown in  FIG. 8 ; 
           [0035]      FIG. 9A  is a vertical section through a carriage designed to operate with an enclosed belt; 
           [0036]      FIG. 10  is an expanded view of the configuration shown in  FIG. 9 ; 
           [0037]      FIG. 11  is an alternative view of  FIG. 10  showing the conveyor from beneath; 
           [0038]      FIG. 12  is a perspective view of the configuration shown in  FIGS. 10 and 11  showing separation of the delivery run and the return run at the head and/or tail ends of the conveyor; 
           [0039]      FIG. 13  is a perspective view of the driven discharge end of the embodiment of the invention using inverted carriages in the return run; 
           [0040]      FIG. 14  is a perspective view from the opposite side of  FIG. 13 ; 
           [0041]      FIG. 15  is a cross-sectional elevation of the delivery run and return run utilising inverted carriages to convey bulk material in the return run; 
           [0042]      FIG. 16  is an enlarged perspective view of the carriages used in  FIG. 15 ; 
           [0043]      FIG. 17  is a perspective view of the carriage of  FIG. 16  in the inverted position; 
           [0044]      FIG. 18  is a perspective view of the vertical turnover wheel with mechanism for tensioning the wire rope; 
           [0045]      FIG. 19  is a perspective view of the drive end arrangement using a tensioning system of the type shown in  FIG. 18 ; 
           [0046]      FIG. 20  is a top perspective view of a carriage showing the engagement with the wire rope; 
           [0047]      FIG. 21  is a detailed view of a portion of  FIG. 20  showing the bush and stop on the wire rope; 
           [0048]      FIG. 22  is a detailed view of the opposite side of the carriage from  FIG. 21 ; 
           [0049]      FIG. 23  shows the carriage relative to the wire rope in an initial position when first in contact with the belt; 
           [0050]      FIG. 24  shows the carriage relative to the wire rope after the belt has stretched; 
           [0051]      FIG. 25  shows a configuration with a removable spring stop and end loop joining methods; 
           [0052]      FIG. 26  shows the engagement of multiple carriages along the wire rope; 
           [0053]      FIG. 27  is an elevation showing the clearance between each carriage and the vertical turnaround wheel; 
           [0054]      FIG. 28  is a vertical view orthogonal to  FIG. 27 ; and 
           [0055]      FIG. 29  is an enlarged perspective view of the wire rope attachment from  FIG. 28 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0056]    In a long distance rail conveyor system of the type shown in  FIG. 1 , the delivery run  1  is typically separated from the support carriages at approximately position  2  so that bulk material conveyed on the delivery run of the carry belt may be discharged at point  3  while the carriages on their rail tracks are sent around a return loop  4  before being reunited with the carry belt in the return run at location  2 . While this is suitable for situations typically over long distances, it requires a wide horizontal footprint for the return loop  4  which is not always available. 
         [0057]    While the rail conveyor technology is ideally suited to long distance transportation due to improved energy efficiency, the technology also has significant advantages when compared to conventional belt conveying systems for shorter conveying distances. Notably, the rail conveyor technology has the advantage of being able to negotiate smaller radius horizontal curves and where necessary convey bulk material in both directions. 
         [0058]    To facilitate shorter conveying operations, it is frequently necessary to reduce the width of the footprint at the head and/or tail end of the system as shown in  FIG. 2  at  5  and  6 . This results in a vastly more compact rail conveyor, at least at the delivery end  6  compared with the prior art loop return system shown in  FIG. 1 . 
         [0059]    To do this, a vertical turnover wheel  7  ( FIG. 3 ) is required to redirect the carriages at each end. The vertical wheel will be pre-tensioned at one end (as will be described further below) to accommodate the extension of the connecting wire rope cable between carriages while driving. 
         [0060]    In a first embodiment of the invention as will now be described with reference to  FIGS. 3 to 7  the carriages  8  supporting the carry belt  10  on rails  9  are rotated through 180° in a helix  11  about an axis in, or parallel to, the return run  12  after leaving the turnover wheel  7 , such that the carriages are returned in an upright orientation as can be seen at  13 . The carry belt  10  is lifted from the carriages  8  as it passes over the turnover wheel  7  and extended to a driving pulley  14  powered by a motor  15 . 
         [0061]    The carry belt may then be returned around a further series of pulleys  16 ,  17 ,  18 ,  19 ,  20  and  21  before returning to the carriages at position  12 . 
         [0062]    The carriages are typically guided through the helix at  11  by guide rails or wires  22  which affect the 180° rotation of the carriages from the inverted position at  23  as they leave the turnover wheel  7  to an upright position at  12 . 
         [0063]    To accommodate the flexing or twisting of each carriage through the helix  11  the carriages are designed to accommodate flexing while being rotated. 
         [0064]    The same arrangement is also in place at the loading end  5  so that the carriages  8  are turned around to return to the discharge end  6 , although in this case the carriages  8  entrained by the turnover wheel  7  are delivered to the delivery run  1  above the return run  12 . 
         [0065]    In one form as shown in  FIG. 4 , the wheels  24  of each carriage  8  are mounted on bogey members  25  which are in turn mounted on the chassis cross-rail  26  of the carriage by way of compressible blocks  27 . The compressible blocks  27  can be located at one or both ends of the carriage  8 . 
         [0066]    This is shown in more detail in  FIG. 5  where the compressible blocks  27  are typically flexible rubber mounting pads. 
         [0067]    The carry belt is typically supported on each carriage by inclined arms  28  extending upwardly from the chassis member  26 . 
         [0068]    An alternative way of accommodating the flexing while the carriages are being rotated is shown in  FIGS. 6 and 7  where the wheels  24  are rotatably mounted on axles  29  supported at the ends of flexible leaf springs  30  which are in turn bolted to the chassis rail  26  at  31 . The leaf springs  30  can be located at one or both ends of the carriage  8 . 
         [0069]    In a further form of the invention as will now be described with reference to  FIGS. 8 to 19  the carriages are designed to travel the return run in an inverted position and are provided with means to support the carry belt in the inverted position. 
         [0070]    As can be seen in  FIG. 13 , the vertical turnover wheel  7  is positioned to turn the carriages from the upright position in the delivery run  32  to an inverted position as shown at  33  in the return run  34 . As in the embodiment described above, the carry belt  10  is lifted from the carriages as they pass over the turnover wheel  7  and passes through a series of rollers generally shown at  35 , driven by a motor  36  before being returned to the inverted carriages at position  37 . This is a simple and effective manner of returning the carriages using a very narrow horizontal footprint as can be clearly seen in  FIGS. 13 and 14  showing the turnover wheel arrangement at both the loading and discharge ends  5 ,  6  and is made possible by providing the carriages with means to support the carry belt in the inverted position as will be described further below. 
         [0071]    The carriage design can be seen most clearly in  FIGS. 8 and 9  where the carriages are typically constructed from pipe bent into a semi-circular section  38  to which is welded two end plates  39  with mountings for bearings rotatably securing the flanged carriage wheels  40 . This results in a carriage which is light in weight and with a relatively low fabrication cost. 
         [0072]    The semi-circular pipe  38  forming the chassis of the carriage is also provided with pads  41  which protrude upwardly from the carriage when in the inverted position  42  to support the carry belt  43  as it drapes in the inverted position over the pads  41  and the chassis tube  38 . The pads are typically formed from polyurethane material. 
         [0073]    The carriages run on rails  44  supported by frame members  45  placed at intervals along the intended run of the conveyor system and designed as appropriate for the terrain. 
         [0074]    In the delivery run as shown at  46 , the carry belt  43  is supported in a troughed configuration by the semi-circular chassis tubes  38  to support the bulk material load  47 . 
         [0075]    The wire rope that interconnects the carriages (as will be described further below) is supported by brackets  48  with the pads  41  providing adequate clearance between the wire rope and the belt along the return side. 
         [0076]    In some situations, it is desirable to fully enclose the load  47  and it is also possible to wrap the carry belt  43  around the load so that it overlaps at position  49  totally enclosing the load  47  as can be seen in  FIG. 9A . Auxiliary components, such as pivoting arms, may be added to the carriages  8  to ensure the belt remains in the enclosed position during operation. 
         [0077]    A more distant view of the configuration shown in  FIG. 9  can be seen in  FIG. 10  where it will be apparent that the rails  44  act as a longitudinal support structure for the frames  45  and tie each vertical support frame  45  together. This can also be seen clearly in  FIG. 11 . 
         [0078]      FIG. 12  is a perspective view of the configuration shown in  FIGS. 10 and 11  showing separation of the delivery run  50  from the return run  51  at separation point  52 . 
         [0079]    It is also possible to utilise the inverted carriages in the return run for conveying bulk material such that material can be conveyed in both directions where required. This will be described further with reference to  FIGS. 15 to 17 . 
         [0080]    As can be seen in  FIG. 15  as well as the inclined tubes  28  supporting the carry belt  43  in the delivery run  53  to provide support for the bulk material load  47 , each carriage can be provided with further support members in the form of bent steel flat bar  54  arranged to support the carry belt  43  in the return run  55  such that a return load  56  can be carried on the return run. 
         [0081]    The configuration of the bars to support the carry belt in the return load can be more clearly seen in  FIG. 16  with the carriage oriented for the supply run and in  FIG. 17  with the carriage inverted and oriented for the return run. Depending on the requirement to convey in both directions, alternative means to support the conveyor belt along the return side are possible with different configurations of the flat bar  54 . 
         [0082]    Given the use of the vertical turnover wheel, tensioning of the carriages can be achieved by using the vertical wheel  7  to tension the wire rope  57  as will be described with reference to  FIGS. 18 and 19 . 
         [0083]    The bearing blocks  59  rotatably supporting the vertical turnover wheel  7  can be mounted on a dolly  60  which is supported for horizontal movement by way of wheels  61  running on rails  62 . Tensioning of the wire rope  57  can be achieved by a winch (not shown), hydraulic or pneumatic cylinders  63 , or suspended weights (not shown). In this manner, the vertical wheel (typically at the head end only of the conveying system) can be moved horizontally in the manner of a horizontal take-up pulley to accommodate the permanent and elastic stretch of the wire rope  57 . The incorporation of this tensioning mechanism in to the head end of the conveyor system can be clearly seen in  FIG. 19 . 
         [0084]    In addition, the carriages  8  may be fixed to the wire rope by means of a mechanical fastener (not shown). Where a mechanical fastener is used, it is preferred that the mechanical fastener is a quick action fastener designed for quick release of the carriages from the rope for maintenance purposes. That is, the quick release enables a reduced time for conducting maintenance operations on the carriages  8  and/or wire rope  57 . 
         [0085]    In the rail conveyor design described above the wire rope  57  interconnecting the carriages may stretch less than the carry belt  43  (particularly when using a fabric belt) and the carriages therefore need to be able to move relative to the wire rope as the belt is stretched under increasing tension along the return side and the carry side. Design of the interaction between the wire rope and the carriages will now be described with reference to  FIGS. 20 to 29 . 
         [0086]    Each carriage is provided with a bush, typically made from nylon or bronze with a hole through the bush slightly larger in diameter than the thickness of the wire rope  57 . Adjacent each carriage the wire rope is provided with a stop  65  typically in the form of a metal crimp and the interaction between the stop  65  and the chassis rail  26  of the carriage is buffered by a small compression spring  66  wound around the wire rope  57 . 
         [0087]    When the carry belt is lifted off the carriages before being redirected around the vertical turnover wheel, the carriages will slow down, sliding back along the wire rope  57  and be re-engaged with the metal crimp  65  buffered by the compression spring  66 . 
         [0088]      FIG. 23  shows the carriage in the driving position with the stop  65  adjacent to the bush  64  and  FIG. 24  shows the movement of the wire rope relative to the carriage as the belt stretches due to increasing tension along the carry and return side. 
         [0089]    This system has significant advantage in minimising the necessary horizontal movement of the vertical wheel by the mechanism described above, and therefore reduces the cost of the system. Furthermore, where belt stretch is greater than the distance between carriages, the belt can be lifted off the carriages at regular intervals along the carry and return sides to allow the carriages to return back to their initial position along the wire rope as shown in  FIG. 23 . 
         [0090]    To allow the carriages to be easily attached and removed from the wire rope the joining and attachment components can be made easily removable as shown in  FIG. 25 . The stop  65  is simply a removable clamping device capable of restraining each carriage and may be provided in the form of a commercially available removable wire rope clamp. The main requirement of the stop is a flat surface perpendicular to the wire rope forming a seat for the compression spring  66 . 
         [0091]    The method of joining the wire rope can also be provided by a number of commercially available solutions but might comprise an eye  67  crimped to one end of the wire rope at  68 , through which is passed the looped end  69  of the wire rope  57  secured by a number of rope clamps  70 . 
         [0092]    The length of the wire rope between joins will be a function of the distance between carriages but typically many carriages  8  would be connected to each length of wire rope  57  as shown in  FIG. 26  where the removable wire rope joint shown in more detail in  FIG. 25  is typically shown at  71 . 
         [0093]    A further consideration in terms of the clamping and joining methods available is the clearance between the carriage chassis member  26  and the inverted flat bar frame  54 , and the vertical wheel  7  as shown in  FIG. 27 . 
         [0094]    The nominal clearance  72  between the vertical wheel  7  and the lower side of the carriage chassis member  26  needs to be maintained at approximately 10 to 15 mm in order to allow correct functioning. 
         [0095]    This criticality is further shown in  FIGS. 28 and 29  where clearance between the vertical wheel  7  and the wire rope clamp and joining components  71  can be seen at  73 . 
         [0096]    The required tension in the wire rope must also provide a restoring force toward the hub of the wheel to overcome the weight of the carriage and the centrifugal force as the carriage moves around the vertical turnover wheel  7 . 
         [0097]    It will be appreciated that while the embodiments have been described as using a wire rope, in other embodiments the wire rope may be replaced by a rope made of nylon, polyester or the like.