Patent Abstract:
A link member having a replaceable wear component and a conveyor belt comprising a link member having a replaceable wear component are described. One aspect of the present invention provides a sacrificial or replaceable wear component that is attached to a conveyor belt. The conveyor belt can be any type of conveyor belt, such as a grid-type or flat-wire conveyor belt. The wear component is attached by mechanical or other means to allow its removal after a certain wear limit has been achieved. A new component can be installed to bring the conveyor belt to nearly new condition. This will extend belt life because only the wear component needs to be replaced, rather than the entire belt.

Full Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to conveyor belts, and in particular, to a link member having a replaceable wear component. 
         [0003]    2. Description of Related Art 
         [0004]    Conveyor belt systems are commonly used in various industrial fields for material handling and processing purposes. For instance, conveyor systems are used within food processing systems in which food items are placed on the support surface of a conveyor belt and processed, while being conveyed from one location to another. Various types of conveyor belts exist, including modular conveyor belts, which are especially popular in food processing systems. Moreover, conveyor systems are often used in a helical accumulator such as that disclose in U.S. Pat. No. 5,070,999 to Layne et al. which allows storage of a large number of items in the conveyor system. 
         [0005]    Conveyor belts used in spiral ovens are driven by a spiral cage made with evenly spaced vertical bars or a smooth cage surface. Due to the high temperatures required in an oven, the cage surface that would normally be covered with plastic in ambient or freezing applications must instead be made with stainless steel. A typical conveyor belt used in food processing equipment would also be made of stainless steel. 
         [0006]    Spiral theory requires that the spiral cage in these applications be driven slightly faster than the belt edge. This difference in speed results in adhesive wear between the inside belt edge and the rotating cage surface. Conveyor belts used in these applications are made with links and rods. The rods terminate at either end with either a weld to the link or a button head welded to the link. A continuous series of these elements are assembled to create an endless conveyor belt. 
         [0007]    The wear that occurs between the rotating cage surface and the inside belt edge results in the reduction of thickness of the button head. If this wear goes unabated, the button head and weld thin to the point that the weld between the link and rod fails, leading to operation failure of the entire belt. This results in both product loss and machine down time. If wear of the inside button heads is noticed upon inspection, users, as required, will “repair” the belts by adding additional weld material to the button head in order to extend the belt life. This “repair” process is timely, costly and inconsistent. 
       SUMMARY OF THE INVENTION 
       [0008]    Thus, there exists a need for a cost-effective wear component that interfaces between the links and rods and the spiral cage. There also exists a need for a wear component that is quickly and easily replaceable. Further, there exists an unfulfilled need for such a wear component that can be made to fit a variety of shapes, sizes and types of conveyor belts. 
         [0009]    In view of the foregoing, one aspect of the present invention provides a sacrificial or replaceable wear component that is attached to a conveyor belt. The conveyor belt can be any type of conveyor belt, such as a grid-type or flat-wire conveyor belt. The wear component is attached by mechanical or other means to allow its removal after a certain wear limit has been achieved. The wear component can be made of plastic, ceramic or any material machined or molded. 
         [0010]    Thus, an advantage of embodiments of the present invention is that the wear component can be removed and a new component can be installed to bring the conveyor belt to nearly new condition. This will extend belt life because only the wear component needs to be replaced, rather than the entire belt. This saves time and money, and provides a new uniform wear surface upon which the belt can be driven. 
         [0011]    The wear component can be rounded, oval or flat, and can be used in standard or extended leg links. In one embodiment, the component is “snapped” into a slot in the extended leg of the link. In another embodiment, the component is snapped around or into the leg of the link. In still another embodiment, the component encapsulates the end of the leg of the link. Alternatively, the component can be attached with a special adhesive. 
         [0012]    According to one embodiment, a conveyor belt of the present invention comprises a plurality of link members, a plurality of pivot rods, and a plurality of wear components. Each link member comprises first and second leg portions and a connecting portion that connects the first and second leg portions at a distal end thereof. Each first and second leg portion comprises a first opening at a proximal end and a second opening at a distal end. Each of the plurality of pivot rods is received in the first opening of each leg portion of one of the plurality of link members and the second opening of each leg portion of an adjacent link member. Each pivot rod includes a weld to one of the plurality of link members at an end thereof. Each wear component is attached proximate to the weld to one of the plurality of link members or one of the plurality of pivot rods. 
         [0013]    A link member is also described. The link member comprises first and second leg portions, a connecting portion and a wear component. Each leg portion comprises a first opening at a proximal end and a second opening at a distal end. The first leg portion further comprises a third opening. The connecting portion connects the first and second leg portions at the distal end thereof. The wear component is received in the third opening. 
         [0014]    Still other aspects, features and advantages of the present invention are readily apparent from the following detailed description, simply by illustrating a number of exemplary embodiments and implementations, including the best mode contemplated for carrying out the present invention. The present invention also is capable of other and different embodiments, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The present invention will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments, but are for explanation and understanding only. 
           [0016]      FIG. 1  is a top view of a link member having a wear component in accordance with an embodiment of the invention. 
           [0017]      FIG. 2  is a top view of a link member having a wear component in accordance with another embodiment of the invention. 
           [0018]      FIG. 3  is a top view of a link member having a wear component in accordance with another embodiment of the invention. 
           [0019]      FIG. 4  is a top view of a link member having a wear component in accordance with another embodiment of the invention. 
           [0020]      FIG. 5  is a top view of an extended leg link member having a wear component in accordance with an embodiment of the invention. 
           [0021]      FIG. 6  is a side view of an extended leg link member having a wear component in accordance with an embodiment of the invention. 
           [0022]      FIG. 7  is a top view of a conveyor belt comprising extended leg link members having wear components in accordance with an embodiment of the invention. 
           [0023]      FIG. 8  is a top perspective view of a conveyor belt comprising extended leg link members having wear components in accordance with an embodiment of the invention. 
           [0024]      FIG. 9  is a side perspective view of a conveyor belt comprising extended leg link members having wear components in accordance with an embodiment of the invention. 
           [0025]      FIG. 10  is a side perspective view of a conveyor belt comprising extended leg link members having wear components in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    A link member having a replaceable wear component is described. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the exemplary embodiments. It is apparent to one skilled in the art, however, that the present invention can be practiced without these specific details or with an equivalent arrangement. 
         [0027]    Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,  FIG. 1  is a top view of a link member  100  having a wear component  180 , in accordance with one implementation of the invention. Link member  100  has a first leg portion  110 , a connecting portion  115  and a second leg portion  120 . Connecting portion  115  connects first leg portion  110  and second leg portion  120  at a distal end of link member  100 . First leg portion  110  and second leg portion  120  extend proximally from connecting portion  115 . Although shown and described as being substantially equal in length, it is contemplated that first leg portion  110  and second leg portion  120  can have different lengths. For example, link member  100  can be an extended leg link member in which first leg portion  110  extends further proximally (i.e., has a longer length) than second leg portion  120 . 
         [0028]    First leg portion  110  has a first opening  130  and a second opening  150 . Second leg portion  120  has a first opening  140  and a second opening  160 . First opening  130  of first leg portion  110  and first opening  140  of second leg portion  120  are positioned at a proximal end of link member  100 . Second opening  150  of first leg portion  110  and second opening  160  of second leg portion  120  are positioned at a distal end of link member  100 . 
         [0029]    Pivot rod  190  is received in first opening  130  of first leg portion  110  and first opening  140  of second leg portion  120 . In this embodiment, pivot rod  190  is welded directly to first leg portion  110  at first opening  130 . It is contemplated, however, that pivot rod  190  may include a button head (not shown) at an end thereof, which is instead welded to first leg portion  110  or is freestanding. A second pivot rod (not shown) is received in second opening  150  of first leg portion  110  and second opening  160  of second leg portion  120 , as well as the first openings of the first and second leg portions of an adjacent link member (not shown). Link member  100  and pivot rod  190  can be made of any material, and can be made of, for example, stainless steel or another metal. 
         [0030]    First leg portion  110  includes a third opening  170  in which a wear component  180  is removably positioned. In this embodiment, third opening  170  is positioned between first opening  130  and second opening  150  in first leg portion  110 . Wear component  180  has a head portion and two leg portions. The ends of the two leg portions of wear component  180  can have a slightly larger diameter than a central area of the two leg portions in order to retain wear component  180  within third opening  170 . 
         [0031]    In order to insert wear component  180  into third opening  170 , the two legs of wear component  180  can be compressed toward each other while being pushed into third opening  170  until the ends of the leg portions snap into place and the head portion of wear component  180  is positioned against first leg portion  110 . Although shown and described with respect to two leg portions, it is contemplated that wear component  180  can have a single leg portion that can be compressed and snapped into place within third opening  170 , without the need for a second leg portion. In either embodiment, the head portion of wear component  180  protrudes beyond the weld or button head between pivot rod  190  and first leg portion  110 . 
         [0032]      FIG. 2  is a top view of link member  100  having a wear component  280 , in accordance with another implementation of the invention. In this embodiment, wear component  280  is C-shaped and is both snapped into third opening  170  of first leg portion  110  and is clipped onto first leg portion  110 . As shown in  FIG. 2 , wear component  280  has two legs connected by an arch that covers the weld between pivot rod  190  and first leg portion  110 . As described above, although pivot rod  190  is directly welded to first leg portion  110  in this embodiment, it is contemplated that pivot rod  190  can further include a button head at an end thereof, and that the button head can instead be welded to first leg portion  110  or be freestanding. In those embodiments, the arch of wear component  280  would cover either the weld between the button head of pivot rod  190  and first leg portion  110  or the button head itself. 
         [0033]    The first leg of wear component  280  is positioned within third opening  170  of first leg portion  110 . Third opening  170  is positioned between first opening  130  and second opening  150  of first leg portion  110 . The second leg of wear component  280  has a recessed portion configured to receive the proximal end of first leg portion  110 , as well as an extended portion having a greater diameter than the recessed portion in order to retain the second leg of wear component  280  on first leg portion  110 . The first leg of wear component  280  has a similar recess and extended portion that allows it to be snapped into third opening  170  and retained therein. 
         [0034]      FIG. 3  is a top view of a link member  300  having a wear component  380 , in accordance with another implementation of the invention. Similar to link member  100 , link member  300  has a first leg portion  310 , a connecting portion  315  and a second leg portion  320 . Connecting portion  315  connects first leg portion  310  and second leg portion  320  at a distal end of link member  300 . First leg portion  310  and second leg portion  320  extend proximally from connecting portion  315 . Although shown and described as being substantially equal in length, it is contemplated that first leg portion  310  and second leg portion  320  can have different lengths. For example, link member  300  can be an extended leg link member in which first leg portion  310  extends further proximally (i.e., has a longer length) than second leg portion  320 . 
         [0035]    First leg portion  310  has a first opening  330  and a second opening  350 . Second leg portion  320  has a first opening  340  and a second opening  360 . First opening  330  of first leg portion  310  and first opening  340  of second leg portion  320  are positioned at a proximal end of link member  100 . Second opening  350  of first leg portion  310  and second opening  360  of second leg portion  320  are positioned at a distal end of link member  300 . 
         [0036]    Pivot rod  390  is received in first opening  330  of first leg portion  310  and first opening  340  of second leg portion  320 . In this embodiment, pivot rod  390  has button head  395 . Button head  395  has a larger diameter than first opening  330  of first leg portion  310  and first opening  340  of second leg portion  320 . Thus, button head  395  retains pivot rod  390  in first opening  330  of first leg portion  310  and first opening  340  of second leg portion  320 . 
         [0037]    In this embodiment, pivot rod  390  is welded to second leg portion  320 . However, it is contemplated that a weld can be present between button head  395  and first leg portion  310 ; between pivot rod  390  and first leg portion  310 ; or that no weld can be present at all. A second pivot rod (not shown) is received in second opening  350  of first leg portion  310  and second opening  360  of second leg portion  320 , as well as the first openings of the first and second leg portions of an adjacent link member (not shown). Link member  300  and pivot rod  390  can be made of any material, and can be made of, for example, stainless steel or another metal. 
         [0038]    Unlike link member  100 , it is not necessary for link member  300  to have a third opening for wear component  380 . Instead, wear component  380  is positioned over button head  395 . Wear component  380  has a flat portion positioned against the flat surface of button head  395  and two side portions curved around the side surfaces of button head  395 . The side portions of wear component  380  can be positioned continuously around the side surfaces of button head  395 , or can be placed at any number of locations around the perimeter of button head  395  as needed to secure wear component  380  in place. In other words, button head  395  fits within a recessed area of wear component  380 . Wear component  380  has a larger diameter at the end of the side portions proximate to first leg portion  310  than at the center of the side portions, i.e., wear component  380  has a lip at the end of the side portions. Thus, wear component  380  can be pushed onto button head  395  and be retained by the end of the side portions hugging the edges of button head  395 . 
         [0039]      FIG. 4  is a top view of a link member  300  having a wear component  480 , in accordance with another implementation of the invention. Pivot rod  490  is received in first opening  330  of first leg portion  310  and first opening  340  of second leg portion  320 . In this embodiment, pivot rod  490  has a threaded end  495  that has a smaller diameter than the remainder of pivot rod  490 . However, it is contemplated that threaded end  495  can have the same or a larger diameter than the remainder of pivot rod  490 . 
         [0040]    In this embodiment, pivot rod  490  is welded to second leg portion  320 . However, it is contemplated that a weld can be present between threaded end  495  and first leg portion  310 ; between pivot rod  490  and first leg portion  310 ; or that no weld can be present at all. A second pivot rod (not shown) is received in second opening  350  of first leg portion  310  and second opening  360  of second leg portion  320 , as well as the first openings of the first and second leg portions of an adjacent link member (not shown). Link member  300  and pivot rod  490  can be made of any material, and can be made of, for example, stainless steel or another metal. 
         [0041]    Again, unlike link member  100 , it is not necessary for link member  300  to have a third opening for wear component  480 . Instead, wear component  480  is threaded or screwed on to threaded end  495 . In this embodiment, wear component  480  has a larger diameter than first opening  330  of first leg portion  310  and first opening  340  of second leg portion  320 . Thus, wear component  480  retains pivot rod  390  in first opening  330  of first leg portion  310  and first opening  340  of second leg portion  320 . In still another embodiment, wear component  480  can be a speed nut or press-on nut (not shown). 
         [0042]      FIG. 5  is a top view of an extended leg link member  500  having a wear component  580 , in accordance with an implementation of the invention. Extended leg link member  500  has a first leg portion  510  and second leg portion  520 . Connecting portion  515  connects first leg portion  510  and second leg portion  520  at a distal end of link member  500 . First leg portion  510  and second leg portion  520  extend proximally from connecting portion  515 . In this embodiment, first leg portion  510  is longer than second leg portion  520 , i.e., extends further proximally than second leg portion  520 . 
         [0043]    First leg portion  510  has a first opening  530  and a second opening  550 . Second leg portion  520  has a first opening  540  and a second opening  560 . Second opening  550  of first leg portion  510  and second opening  560  of second leg portion  520  are positioned at a distal end of extended leg link member  500 . First leg portion  510  has a third opening  570  positioned at a proximal end of extended leg link member  500 . First opening  530  of first leg portion  510  is positioned between third opening  570  and second opening  550  of first leg portion  510 . First opening  540  of second leg portion  520  is positioned parallel to first opening  530  of first leg portion  510 . 
         [0044]    Pivot rod  590  is received in first opening  530  of first leg portion  510  and first opening  540  of second leg portion  520 . In this embodiment, pivot rod  590  is welded directly to first leg portion  510  at first opening  530 . It is contemplated, however, that pivot rod  590  may include a button head (not shown) at an end thereof which is instead welded to first leg portion  510 , or a button head or pivot rod that is instead freestanding without a weld. A second pivot rod (not shown) is received in second opening  550  of first leg portion  510  and second opening  560  of second leg portion  520 , as well as the first openings of the first and second leg portions of an adjacent link member (not shown). Link member  500  and pivot rod  590  can be made of any material, and can be made of, for example, stainless steel or another metal. 
         [0045]    Wear component  580  is removably positioned in third opening  570  of first leg portion  510 . In this embodiment, third opening  570  is positioned further proximally than first opening  530  of first leg portion  510 , such that first opening  530  is positioned between third opening  570  and second opening  550 . Wear component  580  has a head portion and two leg portions. The ends of the two leg portions of wear component  580  can have a slightly larger diameter than a central area of the two leg portions in order to retain wear component  580  within the third opening  570 . 
         [0046]    In order to insert wear component  580  into third opening  570 , the two legs of wear component  580  can be compressed toward each other while being pushed into third opening  570  until the ends of the leg portions snap into place and the head portion of wear component  580  is positioned against first leg portion  510 . Although shown and described with respect to two leg portions, it is contemplated that wear component  580  can have a single leg portion that can be compressed and snapped into place within third opening  570 , without the need for a second leg portion. In either embodiment, the head portion of wear component  580  protrudes beyond the weld or button head between pivot rod  590  and first leg portion  510 . 
         [0047]    In the embodiments described above with respect to  FIGS. 1-5 , the first, second and third openings can be holes, slots or a combination thereof. For example,  FIG. 6  is a side view of an extended leg link member  600  having wear component  680 , in accordance with an implementation of the invention. In  FIG. 6 , only first leg portion  610  is shown. First leg portion  610  has a first opening  630  and a second opening  650 . Second opening  650  is positioned at a distal end of extended leg link member  600 . First leg portion  610  has a third opening  670  positioned at a proximal end of extended leg link member  600 . First opening  630  is positioned between third opening  670  and second opening  650 . Wear component  680  is removably positioned in third opening  670 . As shown in  FIG. 6 , third opening  670  and second opening  650  are slots, while first opening  630  is a hole. However, any combination of slots, holes, and other openings can be used for the first, second and third openings described herein. 
         [0048]      FIG. 7  is a top view of a conveyor belt comprising a plurality of extended leg link members having wear components  780 , in accordance with an implementation of the invention. In one embodiment,  FIG. 7  is a top view of a conveyor belt comprising a plurality of extended leg link members  600  as shown in a side view in  FIG. 6 . Each extended leg link member has a first leg portion  710  and a second leg portion  720 . A connecting portion  715  connects each first leg portion  710  and second leg portion  720  at a distal end of each link member. First leg portion  710  and second leg portion  710  extend proximally from connecting portion  715 . As in  FIG. 5 , first leg portion  710  is longer than second leg portion  720 , i.e., first leg portion  710  extends further proximally than second leg portion  720 . Unlike  FIG. 5 , however, the extended portion of first leg portion  710  also extends in a direction away from the welded end of pivot rods  790 . 
         [0049]    Each first leg portion  710  of  FIG. 7  has a first opening  730  and a second opening  750 . Each second leg portion  720  has a first opening  740  and a second opening  760 . Second opening  750  of first leg portion  710  and second opening  760  of second leg portion  720  are positioned at a distal end of each extended leg link member. Each first leg portion  710  has a third opening  770  positioned at a proximal end of each extended leg link member. First opening  730  of first leg portion  710  is positioned between third opening  770  and second opening  750  of first leg portion  710 . First opening  740  of second leg portion  720  is positioned parallel to first opening  730  of first leg portion  710 . 
         [0050]    Pivot rod  790  is received in first opening  730  of first leg portion  710  and first opening  740  or second leg portion  720 . In this embodiment, each pivot rod  790  is welded directly to first leg portion  710  at first opening  730 . It is contemplated, however, that pivot rod  790  may include a button head (not shown) at an end thereof which is instead welded to first leg portion  710 , or a button head or pivot rod that is instead freestanding without a weld. It is further contemplated that one or more pivot rods  790  may be alternatively or additionally welded to second leg portion  720  at first opening  740 . An adjacent pivot rod  795  is received in second opening  750  of first leg portion  710  and second opening  760  of second leg portion  720 , as well as the first openings of the first and second leg portions  735  and  745 , respectively, of an adjacent extended leg link member. The extended leg link members and pivot rods can be made of any material, and can be made of, for example, stainless steel or another metal. 
         [0051]    Wear component  780  is removably positioned in third opening  770  of each first leg portion  710 . Wear component  780  has a head portion, a single leg portion and a central portion between the head portion and the leg portion. The leg portion of wear component  780  has a slightly larger diameter than the central portion in order to retain wear component  780  within the third opening  770 . 
         [0052]    In order to insert wear component  780  into third opening  770 , the central portion of wear component  780  is aligned with a slot (such as slot  670  of  FIG. 6 ). Wear component  780  is then pushed into the slot such that the head portion of wear component  780  protrudes on one side of first leg portion  710 , and the leg portion of wear component  780  protrudes on the opposite side of first leg portion  710 . Although shown and described with respect to a single leg portion, it is contemplated that wear component  780  can have two or more leg portions that can be compressed and pushed into the slot. In either embodiment, the head portion of wear component  780  protrudes beyond the weld between pivot rod  790  and first leg portion  710  in order to provide a wear surface between the extended link members of the conveyor belt and a spiral cage driving the conveyor belt, as discussed further herein. 
         [0053]      FIGS. 8-10  are top perspective views and side perspective views of a conveyor belt  800  comprising extended leg link members having wear components  880 , in accordance with an implementation of the invention. As described previously, each extended leg link member has a first leg portion  810  and a second leg portion  820 . A connecting portion  815  connects each first leg portion  820  and second leg portion  820 . As in  FIG. 7 , first leg portion  810  is longer than second leg portion  820 , i.e., first leg portion  810  extends further proximally than second leg portion  820  in at least one direction away from second leg portion  820 . The portion of first leg portion  810  extending beyond second leg portion  820  is referred to as the “extended portion” of first leg portion  810 . 
         [0054]    Pivot rods  890  interconnect first openings of first and second leg portions of one extended leg link member with the second openings of first and second leg portions of an adjacent link member, and are welded to the first leg portions of the extended leg link member at an end  825 . The extended leg link members and pivot rods can be made of any material, and can be made of, for example, stainless steel or another metal. 
         [0055]    Wear components  880  are removably positioned in a third opening on the extended portion of each first leg portion  810 . Wear component  880  has a head portion, a single leg portion and a central portion between the head portion and the leg portion. The head and leg portions of wear component  880  have a larger diameter than the central portion in order to retain wear component  880  within the third opening. As shown in this embodiment, the head portion of wear component  880  is flat. However, it is contemplated that the head portion can instead be rounded or any other shape. 
         [0056]    In order to insert wear component  880  into the third opening, the leg portion of wear component  880  is aligned with the third opening; in this case, a hole. Wear component  880  is then pushed or snapped into the hole such that the head portion of wear component  880  protrudes on one side of first leg portion  810 , and the leg portion of wear component  880  protrudes on the opposite side of first leg portion  810 . Although shown and described with respect to a single leg portion, it is contemplated that wear component  880  can have two or more leg portions that can be compressed and pushed into the slot (such as is shown with two leg portions in  FIG. 5 ). In either embodiment, the head portion of wear component  880  protrudes beyond the weld  825  between pivot rod  890  and first leg portion  810  in order to provide a wear surface between the extended link members of the conveyor belt and a spiral cage driving the conveyor belt, as discussed further herein. 
         [0057]    The link members and conveyor belts described with respect to  FIGS. 1-10  herein can be used in spiral ovens driven by spiral cages made with evenly spaced vertical bars or a smooth cage surface. Due to the high temperatures required in an oven, the cage surface that would normally be covered with plastic in ambient or freezing applications is instead made with stainless steel. Similarly, in these applications, the described link members and pivot rods can also be made of stainless steel. 
         [0058]    However, the wear components described herein with respect to  FIGS. 1-10  can be made of a high-temperature plastic, i.e., a plastic having a melting point above 200° F. Such plastics include, but are not limited to, acrylic (PMMA), polyoxymethylene (POM or acetal), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polycarbonate (PC), polyhydroxylalkanoates (PHAs), polyester, polyethylene (PE), polyether ether ketone (PEEK), polypropylene (PP), polystyrene (PS), polyvinylidene chloride (PVDC) and styrene-acrylonitrile (SAN). For extremely high temperature applications, polyether ether ketone (PEEK) is preferred, as it has a melting point of approximately 650° F. 
         [0059]    Because high-temperature plastics such as polyether ether ketone (PEEK) can be expensive in large volumes, described embodiments are cost-effective in that only the wear components need be made of such materials, and standard stainless steel can be maintained on the spiral cages, link members and pivot rods. The described wear components create a uniform wear surface that contact the metal spiral cage. Over time and use, the described wear components that become worn down can be easily removed, disposed of, and replaced by a new wear component, as described above. 
         [0060]    The present invention has been described in relation to particular examples, which are intended in all respects to be illustrative rather than restrictive. Those skilled in the art will appreciate that many different combinations of materials and components will be suitable for practicing the present invention. 
         [0061]    Other implementations of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. Various aspects and/or components of the described embodiments may be used singly or in any combination. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Technology Classification (CPC): 1