Patent Publication Number: US-2020283031-A1

Title: Support rail for a spiral conveyor

Description:
BACKGROUND 
     In a typical spiral conveyor system, a self-stacking belt is arranged in and travels in circular tiers from the bottom of the stack to the top and then perhaps in a second stack the belt travels from the top back down to the bottom of the stack. The bottom belt tier rests on and is driven by inner and outer drive chains which in turn are supported on roller chains that ride on a support rail. The support rail must carry the weight of the entire belt stack as well as the weight of the work product (often food) being carried by the spiral conveyor belt during a thermal processing operation which may involve either heating or cooling the food product. 
     Heretofore the inner and outer rails for supporting and carrying the roller chains were constructed in segments from multiple components, including a formed shelf structure composed of relatively thin gauge material shaped to provide a horizontal support surface for the roller chains. The formed shelf structure is secured to a backing structure presumably of sufficient structural integrity to enable the shelf structure to maintain its shape. The support rails thus configured are made in relatively short sections or segments that are connected together by brackets attached to the backing structure. Typically, at each joint the rail is connected to an upstanding post structure which supports the rail above the floor at the location of the spiral conveyor. 
     It has been difficult to achieve a consistently flat surface along the length of the support rail due to various reasons, including variations in the bending of the sheet material used to form the support shelf. Also, deformation may have occurred in welding the support shelf to the backing structure. Further, the rail structure is constructed from relatively short sections or segments which are bolted together. In addition, the sheet material used to form the shelf structure would not always be able to accommodate the high loads imposed on the shelf structure by a fully loaded spiral conveyor. As a result of the foregoing, bumps, depressions or other discontinuities often occur along the length of the support rail, and in particular along the length of the shelf structure. Such discontinuities, including “bumps,” result in spikes in the forces imposed on the drive chain, roller chain, and bottom belt tiers. This not only imposed high stress levels on these components, but also uneven loads are placed on the motors used to drive the inner and outer drive chains along the inner and outer support rails. 
     The present disclosure provides a support rail construction for a spiral conveyor belt system seeking to address the shortcomings of existing inner and outer support rail constructions. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     A longitudinally curved support rail supports a moving drive chain assembly at the base of a spiral conveyor belt, the drive chain assembly driving the bottom tier of the spiral conveyor belt while being supported by the support rail. The support rail includes an upright web section having a thickness as well as having a top edge and a bottom edge. The support rail also includes a support flange cantilevered laterally outwardly from the web section at an elevation along the height of the web section intermediate the top and bottom edges of the web section. The cantilevered support flange extends laterally from the web section to a location beyond the drive chain assembly to define a supporting ledge for receiving and supporting the drive chain assembly for travel along the support rail. 
     The support rail further includes an integral guide rim section which projects from the web section in a direction opposite to the direction that the support flange extends from the web section. The guide rim section is shaped to support a guide strip interposed between the guide rim section and drive link support columns of the drive chain assembly. The thickness of the web section of the support rail is reduced in the vicinity of the guide rim section. 
     The guide rim section projects laterally from the web section of the support rail a distance coinciding with the envelope of the web section of the support rail that has not been reduced in thickness. 
     The guide rim section is configured to fasten the guide strip to the guide rim section. 
     The top edge of the web section is slanted downwardly toward the drive chain assembly support flange. 
     The support ledge of the drive chain assembly support flange extends substantially horizontally from the web section of the support rail. 
     The drive chain assembly support flange defines an underside and a distal edge. 
     The drive chain assembly support flange defines an upwardly extending groove formed in the underside of the support flange near the distal edge of the support flange. 
     The drive chain assembly support flange defines an outer edge distal from the upright web section, with the outer edge extending downwardly from the upper support ledge a distance greater than the thickness of the adjacent section of the drive chain assembly support flange. 
     The support rail includes a catch trough extending along the support rail at a location beneath the outer edge of the support flange. 
     The support rail is formed in longitudinally extending curved sections. 
     The adjacent ends of the support rail curved sections are welded together to form a unitary, continuous curved rail without need of hardware members for assembling the support rail. 
     The support rail is formed in lengths of from about 2.6 to 3.9 meters in length. The support rail also includes a catch trough extending along the support rail at location beneath the drive chain assembly support flange. 
     The support rail is constructed so that the upright web section and the cantilevered support flange constitute a single unitary structure. 
     The support rail is formed in longitudinally extending sections with adjacent ends of the sections welded together to form a unitary, continuous support rail without need of hardware members for assembling the support rail into a continuous length. 
     The upright web section and the cantilevered support flange of the support rail are constructed as a single unitary extruded, roll formed and/or stamped structure. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is an isometric view of a spiral stacking conveyor belt system including a self-stacking conveyor belt and a drive system for driving the conveyor belt in accordance with embodiments of the present disclosure; 
         FIG. 2  is a top view of the spiral stacking conveyor belt system of  FIG. 1  showing the inner and outer dive chains of the drive system; 
         FIG. 3  is an isometric view showing the inner and outer drive chains mounted on inner and outer support rails supported by upright stands; 
         FIG. 4  is a cross-sectional side view of the spiral stacking conveyor belt system of  FIG. 1  showing the inner and outer drive chains of the drive system mounted on inner and outer support rails; 
         FIG. 5  is an isometric view of a section of the conveyor belt in the spiral stacking conveyor belt system of  FIG. 1 ; 
         FIG. 6  is an isometric view of a length of roller chain of the belt drive system; 
         FIG. 7  is cross-sectional view of the support rails; and 
         FIG. 8  is an isometric view of a section of the support rail of  FIGS. 4 and 7 . 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below in connection with the appended drawings, where like numerals reference like elements, is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Similarly, any steps described herein may be interchangeable with other steps, or combinations of steps, in order to achieve the same or substantially similar result. 
     In the following description, numerous specific details are set forth in order to provide a thorough understanding of exemplary embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that many embodiments of the present disclosure may be practiced without some or all of the specific details. In some instances, well-known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure. Further, it will be appreciated that embodiments of the present disclosure may employ any combination of features described herein. 
     The present application may include references to “directions,” such as “forward,” “rearward,” “front,” “back,” “ahead,” “behind,” “upward,” “downward,” “above,” “below,” “top,” “bottom,” “right hand,” “left hand,” “in,” “out,” “extended,” “advanced,” “retracted,” “proximal,” and “distal.” These references and other similar references in the present application are only to assist in helping describe and understand the present disclosure and are not intended to limit the present invention or disclosure to these directions. 
     The present application may include modifiers such as the words “generally,” “approximately,” “about,” or “substantially.” These terms are meant to serve as modifiers to indicate that the “dimension,” “shape,” “temperature,” “time,” or other physical parameter in question need not be exact, but may vary as long as the function that is required to be performed can be carried out. For example, in the phrase “generally circular in shape,” the shape need not be exactly circular as long as the required function of the structure in question can be carried out. 
     In the following description, various embodiments of the present disclosure are described. In the following description and in the accompanying drawings, the corresponding systems assemblies, apparatus and units may be identified by the same part number, but with an alpha suffix. The descriptions of the parts/components of such systems assemblies, apparatus, and units that are the same or similar are not repeated so as to avoid redundancy in the present application. 
     Referring to  FIGS. 1-3 , embodiments of the present disclosure are directed to spiral stacking conveyor belt systems  20  driven by inner and outer drive systems  22  and  24  and components thereof. The inner and outer drive systems  22  and  24  are generally manufactured from stainless steel components for corrosion resistance. In accordance with embodiments of the present disclosure, the system includes hardened stainless steel components to reduce the elongation of the drive chains over extended periods of use. In accordance with other embodiments of the present disclosure, the system includes hardened and/or dissimilar stainless steel components to reduce galling in the drive chains. 
     Suitable embodiments of spiral stacking conveyor belts are shown and described in U.S. Pat. No. 3,938,651, issued to Alfred et al., and U.S. Pat. No. 5,803,232, issued to Frodeberg, the disclosures of which are hereby expressly incorporated by reference. However, it should be appreciated that other suitable spiral belt assemblies are also within the scope of the present disclosure. Also, a spiral stacking conveyor belt  34  is shown in  FIG. 5 , as discussed below. 
     Referring to  FIG. 1 , when formed as a spiral stack  26 , the pervious conveyor belt  34  is configured into a plurality of superimposed tiers  30  that are stacked on top of each other (i.e., known in the art as “self-stacking” conveyor belt). In that regard, each tier  30  of the stack  26  forms a pervious annulus, through which gaseous cooking or cooling medium may travel, whether for cooking or freezing systems. When formed in a spiral stack  26 , the plurality of tiers  30  creates an inner cylindrical channel  32 , through which the gaseous medium may also travel. Workpieces (such as food products) travel on the conveyor belt  34  and are affected (either cooked or frozen) by gaseous medium in the cooking or freezing chamber. Exemplary spiral stacks  26  may have any number of tiers  30 , typically in the range of about 8 to about 25 tiers. 
     Referring to  FIG. 5 , as a non-limiting example, the conveyor belt  34  may be in the form of a pervious belt mesh  40  for conveying workpieces and formed by transverse rods  42  interconnected by intermediate wire links  43 , as well as formed inner and outer links  44  and  46  positioned at the ends of the transverse rods  42 . The inner and outer links  44  and  46  are configured to enable spiral stacking for the belt tiers  30 , allowing collapsing of the inner links  44  when the belt  34  travels in a curved or circular path and for interconnection with the drive system (see  FIG. 7 ). The inner and outer links  44  and  46  of the conveyor belt  34  interact with and are driven by the respective inner and outer drive systems  22  and  24 . 
     Referring to  FIGS. 2 and 3 , the conveyor belt  34  in the illustrated embodiment of  FIG. 1  is driven by a drive system including inner and outer drive systems  22  and  24 . The inner drive system  22  includes an inner drive station  50 , an inner drive chain  52 , and an inner chain tensioner take up  54 . The outer drive system  24  includes an outer drive station  60 , an outer drive chain  62 , and an outer chain tensioner take up  64 . Referring to  FIG. 4 , the inner drive chain  52  is supported by an inner rail  56  and the outer drive chain  62  is supported by an outer rail  66 . The inner rail  56  and outer rail  66  are in turn supported by a support stand structure  68  composed of upright posts or stands  70  positioned about the circumference of the circular paths of the rails  56  and  66 . 
     In the illustrated embodiment, the inner and outer drive chains  52  and  62  are roller chains, which are supported on the inner and outer support rails  56  and  66  by roller chains  58  for travel along the inner and outer rails  56  and  66 , see  FIG. 4 . Thus, the roller chains  58  support movement of the inner and outer drive chains  52  and  62  along the inner and outer rails  56  and  66 . 
     Describing the spiral conveyor support rail of the present disclosure in more detail, referring specifically to  FIGS. 4-6 , the roller chains  58  for the inner drive chain  52  and outer drive chain  62  are constructed from first roller sets  72  composed of rollers  73  that are axled together by axle  74  to rotate about a horizontal rotational axis  75 . The rollers  73  of the first roller set ride on the upper surface of the support flange section  78  of inner rail  56 . 
     The roller chain  58  also includes a second roller set  76  coupled to the first roller set  72 . The second roller set  76  includes pairs of rollers  77  axled together by axles  77 A to rotate about a vertical axis  77 B so as to bear against the adjacent web portion  80  of the inner rail  56 . The roller chains  58  are made up of sequential first roller sets  72  and second roller sets  76  extending along the lengths of the inner drive chain  52  and outer drive chain  62 . As discussed more fully below, the roller chains  58  function to support the inner drive chain  52  on the inner rail and the outer drive chain  62  on the outer rail  66 . 
     The rollers  56  of the first roller set  72  may be of various material compositions, such as a hardened metallic material capable of carrying the weight of not only the conveyor belt  34 , but also the food product or other items being carried on the conveyor belt. One material from which the rollers  76  may be constructed is a high grade stainless steel. 
     The second roller set  76  functions to bear against the web portion  80  of the inner and outer rails  56  and  66  to minimize friction between the roller chains  58  as the inner and outer drive chains  52  and  62  travel in a curved or circular path along the inner and outer rails  56  and  66 . Thus, the loading on the rollers of the second set is not extremely high, especially with respect to the load being carried by the roller  76 . As such, the rollers of the second set may be composed of a low friction material, such as nylon. 
     Referring specifically to  FIG. 4 , the inner drive chain  52  supports and propels the lowest or first belt tier  30  for travel along the inner and outer rails  56  and  66 . The inner drive chain  52  is composed of segments or sections  83  which are sequentially interconnected to each other end to end to define a continuous drive chain while enabling the sections to pivot sufficiently relative to each other to follow the curvature of the inner rail  56 . A bottom plate  92  is attached to the lower ends of the two spacer columns  84  of each drive chain segment  83 . Bottom link plates  94  are also interconnected to the spacer columns  84  of adjacent chain segments  83  to allow relative pivoting movement between adjacent chain segments  83  during travel in a curved ascending (or descending) path along the inner rail  56 . 
     Correspondingly, a top plate  96  is attached to the upper ends of the spacer columns  84  of a chain segment  83 . The top plate  96  extends horizontally laterally over the top of the inner rail  56  as well as the roller chain  58  and then extends downwardly at  97  to overlap the side of the roller chain  58  opposite to the inner rail web section  80  thereby capturing the roller chain  58  between the inner rail and the downward section  97  of the top plate  96 . A top linking plate  98  interconnects the upper ends of the spacer columns  84  of adjacent chain segments  83  in the manner in which the lower link plates  94  function. 
     Continuing to refer specifically to  FIG. 4 , an upper wall  100  extends upwardly from the top plate  96  lengthwise of the top plate to engage with the inner links  44  of the conveyor belt  34  so as to pull the conveyor belt along with the inner drive chain  52  as the inner drive chain travels along the inner rail. 
     The outer drive chain  62  is constructed somewhat similarly to the inner drive chain  52 . In this regard, the outer drive chain is constructed in chain segments  110  which are connected end to end to form the endless drive chain. Each chain segment  110  includes a pair of upright spacer columns  112  located near the end portions of the chain segments. A bottom plate  120  spans between the lower ends of the spacer columns  112  of each chain segment  110 . A lower link plate  122  is interconnected between the lower ends of the spacer columns  112  of adjacent link segments  110  in the manner of link plates  94  discussed above. 
     A top plate  124  interconnects to upper ends of the spacer columns  112  to define the top sections of the chain segments  110 . The top plate extends laterally inwardly towards the inner rail so as to bear against the rollers  77  of the roller chain  58  whereby the drive chain  62  is supported on the roller chain  58 . A top link plate  126  interconnects the upper ends of adjacent spacer columns  112  of adjacent link segments  110  while allowing relative movement between the chain segments as the outer drive chain  62  travels in a curved ascending (or descending) path along the outer rail  66 . A vertical abutment plate  128  extends downwardly from plate  126  inwardly of the spacer columns  112  to bear against the horizontal rollers  77  of the roller chain  58 . 
     As shown in  FIG. 4 , the outer links  46  of the conveyor belt  34  bear downwardly against the upper surface of the top plate  124  to be supported by the top plate as the conveyor belt travels along the outer rail  66 . 
     Next, describing in more detail the inner  56  and outer  66  rails. In this regard, the inner  56  and outer  66  rails may be of identical or near identical construction in terms of the cross-sectional profiles of the rails. Of course, the rails will differ in their curvature along their lengths due to the larger circumferential path of the outer rail  66  versus the inner rail  56 , as depicted in  FIG. 3 . As such, the following description will reference inner rail  56  with the understanding that the description also applies to the outer rail  66 . 
     Referring specifically to  FIGS. 4 and 6 , the inner rail  56  is constructed with an upright web section  80  that is adapted to be mounted to posts  70  which extend upwardly from the floor to support the rails  56  and  66  above the floor. Through holes  140  are provided in the post web section to receive connectors such as bolts to securely fasten the rails  56  and  66  to the posts  70 . 
     In basic form, the inner rail  56  also includes a support flange portion  78  that extends horizontally from the web portion  80  intermediate the ends of the web portion for receiving and supporting the inner roller chain  58  thereon. In this regard, the length of the flange portion  80  may extend beyond the width of the roller chain so as to provide secure support therefor. The flange portion  78  may be integrally formed with the web portion  80  of the rail  56 . 
     A guide rim  150  is integrated into the web  80  near the upper end thereof and along the sides of the web opposite the flange  78 . The guide rim  150  can be formed by reducing the thickness of the web beneath the guide rim as well as the thickness of the web above the guide rim so as to define the guide rim in the form of a laterally projecting rim section shaped to receive a guide strip structure  152  to extend over the guide rim as shown in  FIG. 4 . The guide strip structure includes a generally channel shaped outer configuration that bears against and closely engages over guide rim  150 . The exterior of the guide strip structure bears against the spacer columns  84  of the inner drive chain  52 . In this regard, the guide strip structure  152  can be composed of a self-lubricating material, a lubricant infused material, or other material that may be sacrificial with respect to the spacer columns  84 , which bear there against. The guide strip structure  152  can be mounted to the guide rim  150  by any appropriate means. 
     It will be appreciated that the guide rim  150  for the guide strip structure  152  can be constructed otherwise than as shown in  FIGS. 4 and 6 . For example, the web portion  80  of the rail  56  may not be “undercut” beneath the guide rim  150 , rather the web portion  80  can be of constant thickness or width along its height, with the guide rim projecting laterally from the web portion so as to form a wider or thicker section of the web portion at the location of the guide rim  150 . 
     The upper end  154  of the web  80  may be sloped toward the support flange  78  so that any liquid that drips onto the top of the post will flow downwardly onto the support flange. As such, any accumulation of liquids on the top of the rail  56  will be minimized. 
     As shown in  FIGS. 4 and 7 , and as noted above, the flange portion  78  of rail  56  extends horizontally laterally from web portion  56  at an elevation intermediate the upper and lower ends of the web section. The thickness of the flange portion  78  may be the same or nearly the same as the cross-sectional thickness of the web portion  80 . Of course, the cross-sectional thickness of flange portion  78  can be varied to accommodate the level of load required to be carried by the flange portion. Further, the flange portion  78  extends laterally a distance beyond the width of the roller chain  58  so as to support the roller chain even if the roller chain is not tight against and is spaced outwardly of the adjacent side edge of the rail web portion. 
     As shown in  FIGS. 4 and 6 , the outer edge of the underside of the support flange  78  is contoured to define a drip nose  160 . Lubricants or other flowable substances on the top surface of the support flange will flow down the outer edge  162  of the support flange and then to beneath the support flange to the location of the drip nose  160 . Due to an undercut  164  made on the bottom edge of the outer portion of the support flange  78 , the drip nose portion  160  projects downwardly further than the adjacent inward portion of the support flange underside. As a consequence, liquids that collect at the drip nose will fall downwardly from the drip nose. A drip plate, drip pan, or catch trough  168  is positioned below the drip nose  160  to collect the lubricants or any other flowable liquids or substances that fall from the drip nose. The lubricants originate from the roller chain  58  which is lubricated for wear resistance. The drip pan  168  will catch such lubricants so as not to fall downwardly on the food items or other work product being transported by the spiral stack conveyor belt system  20 . 
     As illustrated in  FIG. 7 , the profile of the inner rail  56  facilitates being able to form the inner rail in relatively long sections that can be curved as desired, for example, into the diameter of the inner rail, as shown in  FIG. 3 . The sections of the inner rail  56  can be welded end to end so as to result in a continuous integrated structure of high structural integrity. Current conveyor belt support rails are typically made in relatively short sections that are bolted together at each of the posts  70 . This results in a discontinuous rail structure. The surface of the rail structure on which the roller chain rides typically is uneven, especially at the connection locations between rail sections at the support posts  70 . If there is any “bump” or depression in the rail, a spike in the forces on the drive chain and the roller chain occurs at such location, as well as in the bottom belt tiers. Moreover, if the support rails are constructed from short segments, numerous unhygienic bolted joints occur which need to be cleaned thus causing down time of the conveyor belt system  20 . 
     It will be appreciated that by constructing the rail  56  from a singular integrated structure formed, for example, by extruding or roll forming (or stamping), tight dimensional tolerances for the rail structures  56  and  66  can be achieved. This is difficult to accomplish if the rail structure is composed of several components that are welded or otherwise assembled together to form the rail, in the manner of the current art. Moreover, the cross-sectional shape of the present inner rail  56  and outer rail  66  results in high structural integrity of the rail as well as high stiffness. As a result, deflections in the rails  56  and  66  during operation of the conveyor belt system  20  is minimized. Further, due to the tight tolerances achieved during the extruding or roll forming of the rail structure, it is possible to weld sections of the rail structure end to end so as to achieve a substantially seamless, unitary structure along the entire length of the rails  56  and  66 . Heretofore, this has not been achieved in the support rails for spiral stacking conveyor belt systems. 
     As non-limiting examples, the overall height of the rails  56  and  66  can be from about 3.0 to 4.0 inches and the support flange can extend laterally from about 1.5 to 2.25 inches from the web  80 . Also, the web  80  can have a thickness of about 0.425 to 0.525 inches as shown in  FIG. 7 . Further, the thickness of the flange can be about 0.375 to 0.475 inches. The rails  56  and  66  can be formed on sections of lengths of about 8.5 feet (2.6 meters) to about 12.8 feet (3.9 meters). Of course there dimensions can vary depending on various factors, such as the load that the rails need to support and the size of the inner and outer drive chains supported by the rails  56  and  66 . 
     While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.