Abstract:
A chain driven by two sprockets spaced a short distance apart along their common axial centerline. The chain includes elongated pins that extend beyond the outer surfaces of the chain link plates, on both sides, by a distance about equal to the width of the spaced apart sprockets. The chain is aligned midway between the sprockets, and the sprocket teeth drive on the extended portion of the chain pins. Where a flight is attached to the chain links, the pins are extended still further, to fit into the indentations or holes in the flights. This provides an exposed length of each pin in alignment with the sprocket on each side for driving purposes. The chain has a piece extending between the plates to reduce the likelihood of a pin extending further outside of one side plate or the other. A shoulder on the pin further reduces the likelihood of this happening.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of prior-filed, co-pending U.S. application Ser. No. 12/062,069, filed Apr. 3, 2008, and also claims the benefit of prior-filed, co-pending U.S. Provisional Application No. 61/405,404, filed Oct. 21, 2010, the entire contents of both of which are hereby incorporated by reference. 
     
    
     FIELD 
       [0002]    This application relates to a chain and flight conveyor for use in conveying materials in the mining industry and, in particular, to a chain and flight conveyor and a drive sprocket assembly. Still more particularly, this application relates to conveyor chains for continuous miners and chain haulage units. 
         [0003]    Conveyor chains for use on continuous miners and chain haulage units must have the ability to flex sideways to allow them to make turns. For this purpose, the chains include swivel links. Unlike a link from a standard roller or stud-bushed chain, a swivel link cannot be sprocket-driven on its interior, because the space within it is mostly filled with the swivel pin and the lugs that surround the swivel pin. A swivel link can only be sprocket driven on its outer ends. 
         [0004]    U.S. Pat. No. 6,662,932 (the “&#39;932 Patent”) illustrates a chain and flight conveyor with swivel links. As illustrated in  FIGS. 1-4 , the chain and flight conveyor  10  of the &#39;932 Patent includes a pan or conveying deck  14  of, for example, a continuous miner or a shuttle car, and a conveyor chain and flight assembly  18  that travels over the pan  14 . The conveyor  10  also includes a sprocket drive  22 . 
         [0005]    More particularly, as shown in  FIGS. 3-4 , the conveyor chain and flight assembly  18  of the &#39;932 Patent includes a first link assembly  26  and a second link assembly  30 , each of which includes two spaced apart drive pins  34 , each of which has a first end  38  and a second end  42 . Still more particularly, the chain and flight assembly  18  is formed from a plurality of alternating first link assemblies  26  and second link assemblies  30 . 
         [0006]    Each link assembly  26 ,  30  also includes two spaced apart side plates  46 , each of which has two spaced apart openings  50 , each opening  50  receiving a different one of the drive pins  34 . Drive pin retaining means, in the form of press-fitting, retains the drive pins  34  in the side plates  46 . The conveyor chain and flight assembly  18  also includes a swivel assembly  62  connecting the two link assemblies  26 ,  30 , the swivel assembly  62  including a swivel pin  66 , a male connecting lug  70 , and a female connecting lug  74 . 
         [0007]    More particularly, the male connecting lug  70  has a base  75  with a horizontal bore  78  that receives one of the drive pins of the first link assembly  26 , and a tongue  82  connected to the base  75 . The female connecting lug  74  has a base  86  with a horizontal bore  88  that receives one of the drive pins of the second link assembly  30 , and a spaced apart upper lip  90  and lower lip  94  connected to the base  86 . The male connecting lug tongue  82  extends between the spaced apart lips  90  and  94 , each of the lips and the tongue having openings therein that form a bore  98  through the male and female lugs that receives the swivel pin  66 . Swivel pin retaining means, in the form of a weld, retains the swivel pin  66  in the lugs  70  and  74 . 
         [0008]    The conveyor chain and flight assembly  18  also includes a first flight  110  (see  FIG. 2 ) connected to one of the first and the second link assemblies  26 ,  30 , the flight  110  having a flight head  114  having two spaced apart openings  118  and  120 , each of which receives a different one of the first ends of the drive pins  34 . The conveyor chain and flight assembly  18  also includes first flight securing means retaining the drive pin first ends in the first flight head  114  so that the first flight head  114  is spaced from its respective side plate. More particularly, the drive pin first ends are press-fitted or welded to the first flight head  114 . 
         [0009]    The conveyor chain and flight assembly  18  also includes a second flight  124  connected to the one of the first and the second link assemblies, the flight  124  having a flight head  128  having two spaced apart openings  132  and  136 , each of which receives a different one of the second ends of the drive pins  34 . The conveyor chain and flight assembly  18  also includes second flight securing means retaining the drive pin second ends in the second flight head  128  so that the second flight head  128  is spaced from its respective side plate. More particularly, the drive pin second ends are press-fitted or welded to the second flight head  128 . 
         [0010]    In the illustrated embodiment, a pair of such first and second flights  110 ,  124  is connected to each of the second link assemblies  30 . In other embodiments (not shown), the pair of such first and second flights  110 ,  124  can be connected to the first link assemblies  26 . 
         [0011]    As illustrated in  FIGS. 1-2 , the conveyor chain and flight assembly sprocket drive  22  includes two spaced apart drive sprockets  140  and  144 , with each of the drive sprockets  140 ,  144  engaging the drive pins  34  between the side plates and the side plate&#39;s respective flight. The chain  10  is driven by the sprockets  140  and  144  spaced a short distance apart along their common axial centerline (see  FIG. 2 ). The chain  10  includes elongated pins  34  that extend beyond the outer surfaces of the chain link plates  46 , on both sides, by a distance about equal to the width of the spaced apart sprockets  140 ,  144 . The chain  10  is aligned midway between the sprockets  140 ,  144 , and the sprocket teeth drive on the extended portion of the chain pins  34 . Where a flight  110 ,  124  is attached to the chain links, the pins  34  are extended still further to connect to the flights  110 ,  124 . Accordingly, there is an exposed length of each pin  34  in alignment with the sprocket  140 ,  144  on each side for driving purposes. 
         [0012]    The sprockets  140 ,  144  are located away from the center of the chain  10  and therefore away from any interference with the swivel link. The sprockets  140 ,  144  can thus drive the chain  10  on every pitch. 
         [0013]    As an alternative to the swivel assembly  62  connecting the two link assemblies  26 ,  30 , a solid link (not shown in  FIGS. 1-4  but similar to link  191  shown in  FIG. 15 ) can also provide some limited pivotal movement by providing a loose connection to the link assemblies  26 ,  30  by having pin receiving openings that are larger than the pins received in the openings. This permits some limited pivotal movement between the links, serving as a partial swivel joint. 
         [0014]    Both single sprocket and dual sprocket chains are limited in flight section strength by the size of the pins. The usual mode of failure of these chains is bending of the flight pins. The pins can bend such that the flight section snags in the machine return deck. Additionally, it is possible for the edge of a centrifugal loading arm (CLA) to drop down into the space between the side plates and push the side plates apart. Similarly, other obstructions encountered in the conveyor may snag the upper edges of the side plates and cause them to be damaged. 
         [0015]    Press fit connections between the pins and chain flight provide attachment strength and accurate spacing of the chain pins. The press fit connection requires precisely machined holes as well as extra material on the flight to insure that the strength of the flight is not compromised by machining holes on the flights. This adds cost and weight to the chain. In order to provide material on the inner end of the flight, an additional forging technique called upsetting is required in addition to the regular forging operation. 
         [0016]    Disclosed embodiments are an improvement to the above subject matter of the &#39;932 Patent. More particularly, while the &#39;932 Patent included drive pin retaining means in the form of press-fitting or welding of the drive pins in the side plates, welding has proven to be a difficult procedure, especially for field installations. Press-fitting is more field-friendly, but still difficult. Disclosed embodiments may provide relatively easy field assembly of the conveyor chain while addressing the pin movement issues. 
         [0017]    A problem encountered with the &#39;932 Patent chain has been axial motion of a chain pin, so that the pin extends further from one side of the chain than the other. Because welding has proven to be a difficult procedure, especially for field installations, the pins and link side plates have been joined by press fits. Heavier press fits have been tried and have so far prevented pin movement. However, these heavier press fits have the disadvantage of more difficult chain maintenance. 
         [0018]    The mechanism causing pin motion is believed to exist in the underside of the continuous miner conveyor, where the chain moves toward the front of the machine. When the conveyor is hinged sideways, but not to the full extent possible, a gap exists in the side of the conveyor trough. The tension of the chain pulls it sideways in the trough, so that the ends of the chain flights tend to enter the gap. The flights strike the machine frame where the gap ends, and the impact causes the flight section to swivel about the pivoting links. The resulting sideways motion accelerates the side plates transversely, causing relative motion between the side plates and pins. 
         [0019]    To limit this relative motion, a positive retention and field-friendly mechanism may be provided between the pin and side plate. More particularly, certain embodiments provide a piece extending between and connected to the side plates to prevent movement of the side plates away from each other. 
         [0020]    The invention may provide a conveyor including a pan, and a conveyor chain and flight assembly that travels over the pan. The conveyor chain and flight assembly includes a first link assembly and a second link assembly, each of which includes two spaced apart drive pins, each of which has a first end and a second end, and two spaced apart side plates, each of which has two spaced apart openings, each opening receiving a different one of the drive pins. 
         [0021]    In one independent embodiment, the conveyor chain and flight assembly may include drive pin retaining means for retaining the drive pins in the side plates. The drive pin retaining means may include a shoulder on each pin that engages its respective side plate to prevent the side plates, when the side plates engage the shoulder, from moving towards each other. 
         [0022]    In one independent embodiment, the conveyor chain and flight assembly may include, for at least one of the first link assembly and the second link assembly, a piece extending between and connected to the side plates to prevent movement of the side plates away from each other. 
         [0023]    In another independent embodiment, a chain link assembly for a chain conveyor is provided. The assembly may generally include a pair of pins arranged in parallel and spaced apart from one another, each pin having a first end and a second end; a pair of side plates on the pins, the side plates being arranged in parallel and spaced apart from one another, the pins being connected to and extending between the side plates; and structure connected to and extending between the side plates, the structure preventing at least one of movement of the side plates toward one another and movement of the side plates away from one another. 
         [0024]    In yet another independent embodiment, a chain flight assembly may generally include a pair of flight pins, the pins being arranged in parallel and spaced apart from one another, each pin having a first end and a second end; a pair of side plates on the pins, the side plates being arranged in parallel and spaced apart from one another; a pair of flights, one flight being on the first ends of the pins and the other flight being on the second ends of the pins, a first portion of the pins being connected to and extending between one side plate and the one flight, a second portion of the pins being connected to and extending between the other side plate and the other flight; and structure connected to and extending between one of the side plates and an associated flight. 
         [0025]    In a further independent embodiment, a chain flight assembly may generally include a pair of flight pins, the pins being arranged in parallel and spaced apart from one another, each pin having a first end and a second end; a pair of side plates on the pins, the side plates being arranged in parallel and spaced apart from one another, the pins being connected to and extending between the side plates; a pair of flights, one flight being on the first ends of the pins and the other flight being on the second ends of the pins, a first portion of the pins being connected to and extending between one side plate and the one flight, a second portion of the pins being connected to and extending between the other side plate and the other flight; first structure, separate from the pins, connected to and extending between the side plates, the first structure preventing at least one of movement of the side plates toward one another and movement of the side plates away from one another; and second structure connected to and extending between each side plate and an associated flight. 
         [0026]    In another independent embodiment, a method of manufacturing a chain flight assembly is provided. The method may generally include casting, as a unitary piece, the chain flight assembly, the cast chain flight assembly including a pair of flight pins, the pins being arranged in parallel and spaced apart from one another, each pin having a first end and a second end, a pair of side plates on the pins, the side plates being arranged in parallel and spaced apart from one another, and a pair of flights, one flight being on the first ends of the pins and the other flight being on the second ends of the pins, a first portion of the pins being connected to and extending between one side plate and the one flight, a second portion of the pins being connected to and extending between the other side plate and the other flight. 
         [0027]    Further details, independent embodiments and techniques are described in the detailed description below. The summary does not purport to define the invention. The invention is defined by the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  (prior art) is a side view with a partial cutaway of a continuous miner conveyor chain with flights and showing the drive sprocket engaging the chain. 
           [0029]      FIG. 2  (prior art) is a plan view of the chain and flight conveyor being driven by the drive sprockets with a portion of one link assembly broken away. 
           [0030]      FIG. 3  (prior art) is an enlarged view of the partially broken away section of the chain shown in  FIG. 2 . 
           [0031]      FIG. 4  (prior art) is a partial cross-sectional view taken along the line  4 - 4  in  FIG. 3 . 
           [0032]      FIG. 5  is a perspective view of a portion of an improved continuous miner conveyor chain with first and second link assemblies and flights attached to the second link assemblies. 
           [0033]      FIG. 6  is a cross sectional view of one embodiment of the first link assembly. 
           [0034]      FIG. 7  is a cross sectional view of a second embodiment of the first link assembly. 
           [0035]      FIG. 8  is a cross sectional view of a third embodiment of the first link assembly. 
           [0036]      FIG. 9  is a cross sectional view of a fourth embodiment of the first link assembly. 
           [0037]      FIG. 10  is a cross sectional view of a fifth embodiment of the first link assembly. 
           [0038]      FIG. 10A  is a partial cross sectional view of an alternative construction of the first link assembly of  FIG. 10 . 
           [0039]      FIG. 11  is a cross sectional view of a sixth embodiment of the first link assembly. 
           [0040]      FIG. 12  is a cross sectional view of a seventh embodiment of the first link assembly. 
           [0041]      FIG. 13  is a cross sectional view of an eighth embodiment of the first link assembly. 
           [0042]      FIG. 14  is a top cross sectional view of a portion of the conveyor chain, as shown in  FIG. 5 , with first and second link assemblies and flights attached to the second link assemblies, and with a swivel assembly connecting the first and second link assemblies. 
           [0043]      FIG. 15  is another top cross sectional view of a portion of the conveyor chain with first and second link assemblies and flights attached to the second link assemblies, and with a loose link connecting the first and second assemblies. 
           [0044]      FIG. 16  is a perspective view of an alternative embodiment of a chain flight assembly. 
           [0045]      FIG. 17  is an enlarged reverse perspective view of the chain flight assembly of  FIG. 16 . 
           [0046]      FIG. 18  is an enlarged reverse perspective view of another alternative construction of a chain flight assembly. 
           [0047]      FIG. 19  is a side cross-sectional view of the chain flight assembly, taken along line  19 - 19  in  FIG. 18 . 
           [0048]      FIG. 20  is a side cross-sectional view of the chain flight assembly, taken along line  20 - 20  in  FIG. 18   
           [0049]      FIG. 21  is an enlarged view of yet another alternative embodiment of a chain flight assembly. 
           [0050]      FIG. 22  is a perspective view of the chain flight assembly of  FIG. 21  and including support members. 
           [0051]      FIG. 23  is a perspective view of the chain flight assembly of  FIG. 21  and including an alternative construction of the support members. 
           [0052]      FIG. 24  is a perspective view of a further alternative embodiment of a chain flight. 
           [0053]      FIG. 25  is a reverse perspective view of the chain flight assembly of  FIG. 24 . 
           [0054]      FIG. 26  is a perspective view of a chain flight assembly of  FIG. 24 , including swivel link assemblies for coupling to another link in a conveyor chain. 
           [0055]      FIG. 27  is a side cross-sectional view of the chain flight assembly, taken along line  27 - 27  in  FIG. 24 . 
       
    
    
       [0056]    Before any independent embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of the construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other independent embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. Use of “including” and “comprising” and variations thereof as used herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Further, it is to be understood that such terms as “forward”, “rearward”, “left”, “right”, “upward” and “downward”, etc., are words of convenience and are not to be construed as limiting terms. 
       DETAILED DESCRIPTION 
       [0057]    Disclosed embodiments may be an improvement to the above subject matter of the &#39;932 Patent, description of which may be found in the Summary. More particularly, as shown in  FIG. 5 , an improvement relates to the structure of the first link assembly  26  and the second link assembly  30 . As shown in  FIG. 5 , a chain and flight assembly  118  for use on a conveyor includes a first link assembly  126  and a second link assembly  130 . As before, as shown in regards to the first link assembly  126  in  FIGS. 6-13 , each link assembly  126 ,  130  also includes two spaced apart side plates  146 , each of which has two spaced apart openings  150 , each opening  150  receiving a different one of the drive pins  134 . As used herein, interior means between the side plates  146  and exterior means outside of between the side plates  146 . The conveyor chain and flight assembly  118  also includes a swivel assembly  162  connecting the two link assemblies  126 ,  130 , the swivel assembly  162  including a swivel pin  66 , a male connecting lug  70 , and a female connecting lug  74 . The assembled chain and flight assembly  118  is shown in cross section in  FIG. 14 . 
         [0058]      FIG. 15  illustrates another embodiment of the chain and flight assembly  118  in which, instead of a swivel assembly  162 , a solid link  191  is used to provide some limited pivotal movement. The solid link  191  provides a loose connection to the link assemblies  126 ,  130  by having pin receiving openings that are larger than the pins  193  received in the openings. This permits some limited pivotal movement between the links, serving as a partial swivel joint. 
         [0059]    Disclosed embodiments may have two areas of improvement over the &#39;932 Patent. More particularly, the drive pin retaining means for retaining the drive pins in the side plates is different than in the &#39;932 Patent. In this respect, the drive pin retaining means comprises a shoulder  160  on a pin  161  that engages its respective side plate to prevent the side plates, when the side plates engage the shoulder, from moving towards each other, i.e., toward the chain center. In one embodiment, as further explained below, the shoulder comprises an abutment or inner step  162  on a pin  163 . In another embodiment, as further explained below, the shoulder comprises a taper  164  on a pin  165 , and a mating taper  166  in the side plate opening  167 . 
         [0060]    The other improvement is that at least one of the first and second link assemblies also includes a piece, in the form of a bar  170 , that extends between and is connected to the side plates to prevent movement of the side plates away from each other. More particularly, the bar  170  can take the form of a tube  172  or spacers  174  and a nut  176  and bolt  178 , or a threaded bolt ( FIG. 10A ), and a bar welded to the side plates, as further explained below. In a preferred embodiment, each of the first and second link assemblies includes such a piece.  FIGS. 6-13  illustrate different embodiments of the first link assembly  126 . Similar embodiments of the second link assembly  130  are also part of this disclosure. 
         [0061]    More particularly, in one embodiment, as shown in  FIGS. 6-7  and  9 - 12 , the bar includes a bolt  178  extending transversely between the first and second side plates and received in aligned openings  180  and  182  in the side plates. The bolt  178  has a first end with a head on the exterior of one side plate, and a second threaded end on the exterior of the other side plate. A nut  119  and washer  121  (see  FIG. 6 ) are received on the threaded end. In other embodiments ( FIG. 10A ), the second end of the threaded bolt  178 A can be received in a threaded opening  182 A tapped in the side plate  146 A. In such embodiments, a Nord-Lock™ washer  184  (manufactured by NORD-LOCK International AB, Mattmar, Sweden) may be provided on the first end of the bolt  178 A. 
         [0062]    In one embodiment, the bar is in the form of a spacer  127 , as shown in  FIG. 8 , or a rod  125 , as shown in  FIG. 13 , welded  193  transverse between the first and second side plates. 
         [0063]    In one embodiment, the bar also includes a tube  123 , as shown in  FIGS. 6-7 ,  9  and  11 , or a spacer  127 , as shown in  FIG. 12 , that receives the bolt and that extends transverse between the first and second side plates. The tube  123  or the spacer  127  may also prevent the side plates from moving towards one another. 
         [0064]    More particularly, in  FIG. 6 , the pin has two steps  160  and  162  on each end, where there is a change in pin diameter. The inner surface of the side plate is in contact with the inner step  160  of the pin  134 , and prevents motion of the side plate toward the center of the chain, or motion of the pin away from the center of the chain. The outer step  162  of the pin serves to reduce the diameter of the pin further, so that there will not be a press fit with the side plate in the portion of the pin that extends beyond the side plate, to make chain assembly and maintenance easier. There can or cannot be a press fit between the pin and the side plate between the two steps, as desired. 
         [0065]    The bar  170  keeps the two side plates at a fixed distance, and prevents relative motion between the pins and side plates. Instead of the tube, there can be a protrusion  127 , as shown in  FIG. 12 , made integral to the side plate, which has a face contacting the protrusion from the mating side plate. A bolt  178  is still used to keep the side plates from moving away from each other. 
         [0066]    In  FIG. 7 , the pins  135  have no steps. The pins  135  are held in the side plates by a press fit. The first link assembly  126  does include, however, a means of keeping the two side plates at a fixed distance. In this case, that means is the bar  170  including a bolt  178 , nut  119 , and tube  123 . 
         [0067]    In  FIG. 8 , which is similar to  FIG. 7 , except that instead of a bolt, nut, and tube, there is a spacer  127  that is attached to the side plate as by welding. This embodiment would likely be used for those links that have scraper flights attached, because those links are not usually disassembled in service and already undergo a welding process to attach the flights. 
         [0068]    In  FIG. 9 , the pin has steps, and there is a step in the side plate opening. The step in the side plate bore contacts the step in the pin. A press fit exists for most of the length of the side plate bore. Outboard of the step in the side plate opening, the bore has a clearance fit with the pin. 
         [0069]    In  FIG. 10 , the change in diameter in the pins  136  comprises a portion of relatively shallow taper. As illustrated, the total taper is 5 degrees (2.5 degrees from the pin axis to the outer surface). The side plate bores openings are made to a matching taper. A bolt and nut are provided to prevent outward motion of the side plates. An advantage of the construction shown in  FIG. 10  is that cylindrical press fits are eliminated, and tightening the bolt and nut can assemble the link assembly. Unthreading the bolt and nut, and tapping one of the side plates with a hammer can disassemble it. 
         [0070]    In the embodiment illustrated in  FIG. 10A , a taper fit is provided between one end of the pins  134  and the associated side plate  146 , and a press fit is provided between the other end of the pins  134  and the other side plate  146 . An indication (e.g., a recess, hole or other marking) is provided on the one end of the pin  134  to identify the taper fit. In other constructions (not shown), the identification may be provided on the other end of the pin  134  to identify the press fit, in addition to or instead of the indication of the taper fit. In still other constructions (not shown), the indication may be provided on the side plate(s)  146 , in addition to or instead of the indication(s) on the pin  134 . 
         [0071]    In  FIG. 11 , which is similar to  FIG. 10 , a tube  123  is used, as in  FIG. 6 . The tube length would be dimensioned so that the side plate contacts the pins on the tapers first. Further tightening of the bolt and nut will cause deflection of the side plates until the inner surfaces of the side plates contact the tube. A purpose of the tube is to prevent excess deflection of the side plates due to bolt tension, which could cause improper seating of the tapered fits. It may also serve to reduce fatigue stress on the bolt and side plates. 
         [0072]      FIGS. 16-20  show alternative embodiments of a chain flight assembly  300 . Reference numbers for these embodiments begin with “ 300 ” to distinguish from the embodiments described above. 
         [0073]    As shown in  FIGS. 16-17 , the assembly  300  includes a pair of flight pins  304 , a pair of side plates  312 , a pair of flights  320 , support structure  328  between the side plates  312  and support structure  336  between each side plate  312  and the associated flight  320 . The pins  304  are arranged in parallel and spaced apart from one another, and each pin  304  includes a first end  344  and a second end  348 . The side plates  312  are also positioned in a parallel, spaced-apart manner. Each side plate  312  has an outer side  364  and an inner side  368 . The side plates  312  are mounted on the pins  304  such that the inner side  368  of one side plate  312  faces the inner side  368  of the other side plate  312 . The pins  304  and the side plates  312  define an open area therebetween. 
         [0074]    The portion of the pins  304  between the inner sides  368  of the side plates  312  is adapted to receive a swivel assembly  62  for connecting the assembly  300  with adjacent chain links to form the conveyor chain. The swivel assembly  62  is similar to that described above and shown in  FIGS. 2-5  and  14 . The portion of the pins  304  adjacent the outer side  364  of each side plate  312  receive the teeth of a drive sprocket (not shown but similar to the drive sprockets  140 ,  144 ) to move the assembly  300  along a conveyor path. 
         [0075]    Each flight  320  provides a scraper edge  384  ( FIG. 16 ) and includes a shoulder  388  having a pair of openings  392 . The shoulder  388  is arranged parallel to and spaced from the associated side plate  312 . The openings  392  of the one flight  320  receive the first ends  344  of the pins  304 , and the openings  392  of the other flight  320  receive the second ends  348  of the pins  304 . “Opening” generally includes a space or area sufficient to receive a pin  304  for connection to the flight  320  and may include a through-hole (as shown in  FIGS. 16-18 ), a slot or groove (as shown in  FIGS. 19-21 ) which only partially surrounds the pins, or an indentation (e.g., a recess with an end surface) (not shown). 
         [0076]    In the embodiment of  FIGS. 16-18 , the pins  304  are secured within the openings  392  by a press fit connection. In other constructions (not shown), a different connection (e.g., welding) may be used. 
         [0077]    The pins  304  and the associated side plate  312  and shoulder  388  define an open area therebetween. The portion of the pins  304  the associated side plate  312  and shoulder  388  receive the teeth of the drive sprocket (not shown but similar to the drive sprockets  140 ,  144 ) to move the assembly  300  along a conveyor path. The open area accommodates the sprocket teeth. 
         [0078]    The support structure  328  extends between the side plates  312  and, in the illustrated construction, includes (see  FIG. 19 ) an upper support  396  (also shown in  FIG. 16 ) on the top of the assembly  300  and a lower support  404  (also shown in  FIG. 17 ) on the bottom of the assembly  300 . The support structure  328  is positioned in the open area defined between the pins  304  and the side plates  312 , and a clearance is provided between the pins  304  and each of the support  396 ,  404  to allow insertion of a swivel assembly  62  around the pins  304  and to permit movement of the swivel assembly  62 . 
         [0079]    In the embodiment illustrated in  FIGS. 16-17 , the upper support  396  and the lower support  404  include a protrusion formed with and extending from each side plate  312  and joined together, for example, by welding. In other constructions (not shown), the upper support  396  and/or the lower support  404  (rather than only a portion thereof) may be formed integrally with one side plate  312  and connected to the other side plate  312 . In an alternative embodiment (see  FIG. 18 ), the upper support  396  and the lower support  404  (not shown) are formed separately from the side plates  312  and joined to the side plates  312 . Although the embodiment of  FIG. 18  requires additional welding (at each end of the support  396 ,  404 ), it may simplify manufacture of the side plates  312 . 
         [0080]    Referring again to  FIG. 16 , the support structure  336  includes plates  420  (four in the illustrated construction) secured between the flight shoulders  388  and the outer side  364  of each side plate  312 . Each plate  420  is positioned outside of the area engaged by the sprocket teeth. In the illustrated construction (see  FIG. 20 ), each plate  420  is positioned above the associated pin  304  to minimize interference with the sprocket teeth engaging the pins  304 , and the support structure  336  and the pins  304  have a non-circular cross-section. 
         [0081]    In the embodiment illustrated in  FIG. 16 , each plate  420  is formed integrally with and extends outwardly from the outer side  364  of the side plate  312 . The plate  420  is coupled to the associated shoulder  388 , for example, by welding. In other constructions (not shown), each plate  420  may be formed integrally with the flight shoulder  388  and have a free end coupled to the outer side  364  of the side plate  312 . In further alternative constructions (not shown), each plate  420  can be formed as a protrusion on the side plate  312  and a protrusion on the flight shoulder  388 , with each protrusion being joined together (in a manner similar to that described above with respect to  FIG. 16 ). In yet other alternative construction (see  FIG. 18 ), each plate  420  is formed separately and joined the associated side plate  312  and shoulder  388 . Although the embodiment of  FIG. 18  requires additional welding (at each end of the plate  420  rather than at only one end), it may simplify manufacture of the side plates  312  and the flights  320 . 
         [0082]    The addition of the support structure(s)  328  and/or  336  generally improves the strength, rigidity, etc. of the assembly  300 . As shown in  FIGS. 19-20 , the support structure  328  increases the section modulus of the portion of the pins  304  between the side plates  312  ( FIG. 19 ), and the support structure  336  increases the section modulus of the portion of the pins  304  between the flights  320  and the side plates  312  ( FIG. 20 ). In a conventional chain flight assembly, both portions are limited only to the section modulus of the two pins  304 . In addition, the top surface of each support structure  328 ,  336  is, in the illustrated constructions, flush with the top of the side plates  312  and flight shoulders  388 , providing a more uniform top surface of the assembly  300  with less opportunity snag on CLAs or other obstructions. 
         [0083]    In further embodiments, shown in  FIGS. 21-23 , a chain flight assembly  500  is constructed without press fit connections between pins  504  and flight shoulders  588 . For this embodiment, elements that are similar to the elements of the embodiments of  FIGS. 16-18  are denoted by the same reference number, plus  200 . 
         [0084]    As shown in  FIG. 21 , the flight pins  504  are welded directly onto each flight shoulder  588  without material encircling the outer surface of the pins  504 . In the illustrated construction, the side plates  512  are press fit onto the pins  504  in order to ensure that the pins  504  are sufficiently spaced to receive the drive sprocket teeth. Without the press fit on the flight shoulder  588 , the exposed portion of each pin  504  is increased. This additional exposure provides additional length for welding the pins  504  to the flight shoulders  588  to provide the requisite strength for the assembly  500 . Additional welded joints can be provided on the assembly  500  in addition to those shown in the illustrated embodiment. 
         [0085]    In the assembly  500 , the side plates  512  are formed to provide accurate spacing of the pins  504 . This may allow the press fit connection between the pins  504  and the flight shoulder  588  to be eliminated, simplifying the machining and pressing operations. This may also allow the pins  504  to have a larger diameter, increasing the section modulus (and, therefore, the strength) throughout the assembly  500 . The reduction in material of the flight shoulder  588  simplifies fabrication of the flights  520 , such that the flights  520  are cheaper, lighter, etc. In addition, the elimination of the material around the flight shoulder  588  may permit the flight  520  to have a longer scraper edge  584 , improving the ability of the assembly  500  to carry material along the path of the conveyor. 
         [0086]      FIG. 22  shows the assembly  500  of  FIG. 21  including support structure  528  secured between the side plates  512  and support structure  536  secured between the side plates  512  and the flight shoulders  588 . In a further alternative, shown in  FIG. 23 , the second support  536  may be formed as a u-shaped plate  590  having a base that is secured to the top of the flight shoulder  588  and arms attached to the side plate  512 . 
         [0087]      FIGS. 24-27  illustrate another embodiment in which a chain flight assembly  700  is formed as a unitary piece. For this embodiment, elements that are similar to the elements of the embodiments of  FIGS. 21-23  are denoted by similar reference numbers, plus  200 . 
         [0088]    As shown in  FIGS. 24-25 , the assembly  700  includes a pair of flight pins  704 , a pair of side plates  712 , and a pair of flights  720 . The illustrated assembly  700  also includes support structure  728 , including an upper member  796 , between the side plates  712 . The support structure  728  may also include a lower member (not shown), though this may add complexity to the process for forming the assembly  700 . 
         [0089]    The area between the inner sides  768  of the side plates  712  defines a chain engaging area  780 . As shown in  FIG. 26 , a swivel assembly  62  (as described above in relation to  FIGS. 3-5 ) for connecting the assembly  700  with adjacent chain links to form a conveyor chain, engages the pins  704  in the chain engaging area  780 . The support structure  728  does not interfere with the swivel assembly  62 . 
         [0090]    The area between each flight  720  and each respective side plate  712  defines a sprocket engaging area  776 . The illustrated assembly  700  also includes support structure  736  between each side plate  712  and the associated flight shoulder  788 . In the illustrated embodiment (see  FIG. 27 ), the support structure  736  is formed with the pins  704 . The support structure  736  is outside of the sprocket engaging area  776 . The support structure  736  provides the pins  704  with a non-circular cross-section. The illustrated pins  704  are also eccentric relative to the axis of the pins  704 . 
         [0091]    The assembly  700  may be formed using a lost foam process which permits high precision casting of parts with complicated structures. In the lost foam process, a mold of the assembly  700  is made from polystyrene foam, rather than wax, as is done in an investment casting process. This method of fabrication eliminates several machining and assembly operations, simplifying production of the assembly  700 . Alternatively, the assembly  700  may be made using another casting process, such as investment casting. 
         [0092]    Thus, the invention may provide, among other things, a chain flight assembly with support structure between the side plates and/or between each side plate and the associated flight. One or more independent features and independent advantages of the invention may be apparent from the following claims.