Abstract:
A conveyor flight for a chain comprising at least two spaced apart links, and two side plates that connect the links, with each side plate including two spaced apart extension pins extending from the side plate. The flight comprises a metal support, and the metal support includes two spaced apart cylindrical portions adapted to receive the two spaced apart extension pins. The flight also includes a flexible casing surrounding the metal support.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of prior-filed, co-pending U.S. patent application Ser. No. 14/624,749, filed Feb. 18, 2015, which is a continuation of U.S. patent application Ser. No. 13/220,048, filed Aug. 29, 2011, which is a continuation-in-part of prior-filed, co-pending U.S. application Ser. No. 12/433,332, filed Apr. 30, 2009. The entire contents of all of these documents are hereby incorporated by reference. 
    
    
     FIELD 
     The present invention relates to a chain and flight conveyor for use in conveying material in the mining industry and, in particular, to an improved design of a chain and flight conveyor. Still more particularly, this invention relates to conveyor chains for continuous miners and chain haulage units. 
     SUMMARY 
     Conveyor flights with various coatings have been attempted in the past. The primary reason for these coatings was for noise control. While the coatings have been shown to reduce conveyor noise by 5-10 dBA, these materials wore off of the flights relatively quickly and were determined not to be of sufficient value for commercial use on continuous miners or longwall equipment. The coatings compressed beyond their working limit and began to tear and chuck out. One of the reasons for this failure is that the coating was too thin. There is a limited amount of space available on the conveyor for the flight bars, so in order to make the coating thicker, the integrity of the existing flight is compromised. 
     Urethane coating on conveyor chain flights has proven effective in reducing the noise exposure of continuous miner operators. Problems preventing widespread acceptance of this solution include the cost of implementation and maintenance of the chain, the durability of the urethane coating, etc. 
     The most successful urethane-coated flight design to date is a standard forged steel conveyor flight, which is machined down to reduce its thickness and thus allow room for the urethane coating. The machined-down flight is then used as a flight core, which is encapsulated in the urethane coating. However, the coating is thinner than desired, and the corners of the steel flight cause stress concentration on the urethane coating. The end of the flight nearest the chain is currently enlarged and has holes to fit the chain pins. The urethane coating is undesirably thin due to the enlarged end of the flight. 
     The flight core is welded integrally to the chain flight section, which is a part of the chain assembly. Replacing a flight due to loss of the urethane coating is expensive and difficult. If more than a few flights have lost their urethane coating, it is not economical to repair the chain, and the entire chain must be replaced. 
     An independent object of this disclosure is to provide a conveyor chain having replaceable urethane-coated flights. With a conveyor chain having replaceable urethane-coated flights, it is then possible to replace damaged urethane coated flights in a few minutes with minimum downtime of the continuous miner. 
     In one independent embodiment, a conveyor flight for a chain includes at least two spaced apart links, and two side plates that connect the links, with each side plate including two spaced apart extension pins extending from the side plate. The flight may include a metal support, and the metal support may include two spaced apart cylindrical portions adapted to receive the two spaced apart extension pins. The flight may also include a flexible casing surrounding the metal support. 
     In another independent embodiment, a flight is provided for a chain flight assembly of a conveyor chain, the chain flight assembly including a pair of parallel flight pins spaced apart by a distance, each pin having a length, a pair of spaced apart, parallel side plates mounted on the pins, and at least one flight. The flight may generally include a flight core including an arm and a pair of parallel tubes spaced apart by the distance, the arm being between and coupled to each tube, each tube having a first end and a second end, and a flight coating encapsulating and secured to the core, the coating including a first end and a second end, the first end including a pair of openings. The core and the coating may form a unitary flight, the unitary flight being connectable to the pins, the first end of each tube being adapted to receive a portion of the length of an associated pin, each opening in the coating being adapted to receive therethrough a portion of the associated pin. 
     In a further independent embodiment, a chain flight assembly of a conveyor chain is provided. The assembly may generally include a pair of parallel flight pins spaced apart by a distance, each pin having a length, a pair of spaced apart, parallel side plates mounted on the pins, and at least one removable flight. The flight may include a flight core including an arm and a pair of parallel tubes spaced apart by the distance, the arm being between and coupled to each tube, each tube having a first end and a second end, and a flight coating encapsulating and secured to the core, the coating including a first end and a second end, the first end including a pair of openings. The core and the coating may form a unitary flight, the unitary flight being removably connectable to the pins, the first end of each tube removably receiving a portion of the length of an associated pin, each opening in the coating receiving therethrough a portion of the associated pin. 
     In yet another independent embodiment, a chain flight assembly of a conveyor chain is provided. The assembly may generally include a pair of parallel flight pins spaced apart by a distance, each pin having an outer surface and a length, a pair of spaced apart, parallel side plates mounted on the pins, at least one removable flight including a pair of openings spaced apart by the distance, each opening having an inner surface and removably receiving an associated pin, and adhesive between the inner surface of each opening and the outer surface of the associated pin to removably connect the flight to the pins. 
     In another independent embodiment, a method of assembling a chain flight assembly of a conveyor chain is provided. The method may generally include providing a pair of parallel flight pins spaced apart by a distance, each pin having a length, mounting a pair of spaced apart, parallel side plates mounted on the pins, providing at least one flight, the flight including a flight core including an arm and a pair of parallel tubes spaced apart by the distance, the arm being between and coupled to each tube, each tube having a first end and a second end, and a flight coating including a first end and a second end, the first end including a pair of openings, providing including encapsulating the core in the coating to form a unitary flight, and after encapsulating, removably connecting the unitary flight to the pins including removably receiving a portion of the length of an associated pin in the first end of each tube, and removably receiving a portion of the associated pin through each opening in the coating. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial perspective view of a conveyor including a chain and flights. 
         FIG. 2  is a perspective view of one flight including an internal core and an external urethane coating. 
         FIG. 3  is a perspective view of the internal core shown in  FIG. 2 . 
         FIG. 4  is a perspective view of an alternate embodiment of the internal core shown in  FIG. 3 . 
         FIG. 5  is a partial perspective view of an alternate embodiment of a conveyor including a chain and flights. 
         FIG. 6  is a perspective view of an alternative embodiment of a chain flight assembly. 
         FIG. 7  is an exploded perspective view of the chain flight assembly shown in  FIG. 6 . 
         FIG. 8  is a perspective view of a core of the chain flight assembly shown in  FIG. 6 . 
         FIG. 9  is a perspective view of an external coating for the chain flight assembly shown in  FIG. 6 . 
         FIG. 10  is a perspective view of another alternative embodiment of the chain flight assembly. 
     
    
    
     Before any independent embodiments of the disclosure is explained in detail, it is to be understood that the disclosure 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 disclosure 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 
     A conveyor  10  including a chain  14  and flights  18  is shown in  FIG. 1 . The flight  18  includes sound dampening material in the form of a urethane coating  20  ( FIG. 2 ), and a metal support  22 , in the form of an embedded steel plate core, is shown in  FIGS. 1 and 3 . In other embodiments, other less preferred forms of a metal support, such as a block (not shown), can be used. 
     More particularly, the chain  14 , as illustrated in  FIG. 1 , includes two swivel links  26  connected by two side plates  30 . Although only two swivel links  26  connected by two side plates  30  are shown, the chain  14  usually is an endless chain (not shown), and flights  18  are attached at spaced apart locations along the chain  14 . 
     Extending perpendicular to the direction of chain travel are two spaced apart pins  34  that extend outwardly from each of the side plates  30 . Each of the flights  18  is attached to the spaced apart pins  34 , as further explained below. As illustrated in  FIG. 1 , one set of the two spaced apart pins  34  extend to the left of the chain  14  and one set of the two spaced apart pins  34  extend to the right of the chain  14 . 
     Each flight  18  has the thin-walled steel core  22 , leaving space for adequate thickness of the sound-dampening coating  20 . The core  22 , as shown in  FIG. 3 , is a flat steel plate having a first end  40  and a second end  44 , and a left edge  48  and a right edge  52 , as shown in  FIG. 3 . Each of the left and right edges of the core  22  has a cylindrical portion  50  that defines a cylindrical opening  54  that extends the length of the core  22 . The cylindrical openings  54  receive the elongated chain pins  34 . The core  22  is clamped onto the flight pins  34  by clamping means in the form of rivets or threaded fasteners  56  (see  FIG. 1 ) that pass through openings  58  that extend only through the metal support  22 . The core  22 , together with the elongated pins  34 , provides strength and rigidity to support the urethane outer shell  20  of the flight  18 . 
     In order to permit access to the rivets or threaded fasteners  56 , so that the flight  18  can be removed from the conveyor  10 , or so a new flight  18  can replace a damaged one, openings  60  are present in the urethane coating  20  above the openings  58  through the metal support  22 . 
     In one embodiment, not shown, the sound-dampening flight  18  can be made in multiple pieces that are glued together and onto the cores  22  at the same time. In the preferred embodiment, the flight  18  is molded directly onto the core  22 . More particularly, the core  22  is inserted into a mold, and then the sound-dampening material  20  is poured over the core. The core can be one piece or two piece. Shown in  FIG. 3  is a one-piece core  22  and shown in  FIG. 4  is a core  72  made of two identical pieces  74  and  76 , arranged symmetrically. The core can also be made into a single piece by welding two pieces along the edges. The one-piece core provides more reliable clamping onto the chain pins  34 , but the two-piece core is be less expensive to manufacture. 
     As shown in  FIG. 5 , the length of the cylindrical openings  54  need not be the entire length of the core  22 . When pins  34  that do not extend the entire length of the core  22  are used for economical reasons, the length of the cylindrical openings  54  can be suited to the length of pin extension  34 . This also allows various widths of chain assembly to be easily made by simply selecting the flights of the desired width, and keeping the pin length common. 
     A dual-sprocket conveyor chain from U.S. Pat. No. 6,662,932, which is incorporated herein by reference, is shown in the illustrations. The concept could also be applied to standard single-sprocket conveyor chain. In the illustrations, the urethane flight is shown partially transparent to reveal the flight pins and core within. 
       FIGS. 6-9  show a chain flight assembly  400  according to another embodiment of the invention. The chain flight assembly  400  shown in  FIGS. 6-7  is similar to the chain flight assembly described above in regard to  FIGS. 1-5 , and only differences will be discussed herein. Common elements have the same reference number, plus “ 400 ”. 
     The chain flight assembly  400  includes chain flights  418 , swivel links  426 , side plates  430 , and flight pins  434 . As shown in  FIGS. 7-8 , the chain flight  418  includes a flight coating  420 , made from a sound dampening material, such as urethane, and an inner flight core  422  made from a rigid material, such as steel. 
       FIG. 8  shows the core  422  in greater detail. The illustrated core  422  includes two parallel tubes  438  and an arm  442  coupled to the tubes  438 . Each tube  438  includes a first end  446  and a second end  464 , and the tubes  438  are spaced apart by a distance equal to the pitch length of the chain  14 . The tubes  438  have an inner surface  466  defining an inner diameter. The inner diameter is slightly larger than the diameter of the pins  434  to permit a clearance fit between the tubes  438  and an outer surface of the pins  434 . 
     The arm  442  includes a first end  468  proximate the first ends  446  of the tubes  438 , a second end  480 , an upper surface  484 , and a lower surface  488 . The arm  442  extends parallel to the tubes  438  toward the second end  480  that, in the illustrated construction, is beyond the second ends  464  of the tubes  438 . The arm  442  also includes multiple openings  492  extending between the upper surface  484  and the lower surface  488 . In other embodiments, the arm  442  may include more or fewer openings  492  having various sizes. 
     The flight coating  420  is made from urethane or another sound dampening material. As shown in  FIG. 9 , the illustrated coating  420  substantially encapsulates the core  422 , covering the upper, lower and outer end surfaces of the core  422 . In other constructions, the coating  420  may cover the inner end surface of the core  422 . The coating  420  extends through and fills the openings  492  of the arm  442 , strengthening the bond between the coating  420  and the arm  442 . 
     Referring again to  FIG. 7 , the pins  434  have an extended length to attach to the core  422 . The flights  418  are connected to the pins  434 , and, in the present embodiment, adhesive provides structure to connect the flights  418  and pins  434 . To assemble the flight  418  to the chain  14 , an adhesive or chocking compound is applied to the inside of the tubes  438  and/or to the pins  434 . The pins  434  may be prepared to enhance the adhesive bond, which may include knurling, grooving, or sandblasting the outer surface of the pins  434 . The tubes  438  are slid over the pins  434 , securing the flight  418  with respect to the chain flight assembly  400 . The adhesive fills the space between the inside of the tube  438  and the pin  434 . 
     Suitable adhesives have a shear strength of 5,000 psi, and the tubes  438  and the pins  434  are designed to have an adequate bonding area to provide the requisite strength for the chain flight assembly  400 . In addition, the selected adhesive has a melting temperature such that the application of heat causes the adhesive to melt and permits the operator to remove and replace a worn or damaged flight  418 . After applying additional adhesive to the pins  434  and/or tubes  438  (if necessary), a new, replacement flight  418  is installed on the pins  434 . 
     The modular design of the flight  418  shown in  FIGS. 6-9  simplifies replacement of a broken flight without requiring disconnecting the chain  14  and replacing an entire chain flight assembly  400 . The rigid flight core  422  provides strength and rigidity to the flight  418 , while the flight coating  420  provides sound dampening to reduce the noise caused by operation of the conveyor  10 . 
     In addition, the flight core  422  and flight coating  420  simplify the manufacturing process by eliminating the need to first attach a flight onto a chain flight assembly and then apply a coating to each flight. Instead, the flights  418  may be produced individually by first manufacturing the flight core  422  and then coating the core  422  in the coating  420 . This reduces the cost of forming a chain flight assembly  400  having sound dampening flights  418 . 
     The length of the tubes  438  may be adjusted depending on the desired amount of contact surface between the pins  434  and the tubes  438 . Also, the length and shape of the arm  442  may be adjusted depending on the desired strength or rigidity of the flight  418 . 
       FIG. 10  shows an alternative embodiment of a chain flight assembly  500  including a flight  518  in which the core  522  is connected to (e.g., slid over) the ends of the pins  534 . The core  522  extends nearly the entire length of the flight coating  520 , providing greater strength to the assembly. 
     In yet another independent embodiment (not shown), the flight is made from a material having sound dampening properties, such that a separate coating is not required, and with sufficient strength, such that a separate core element is not required. One example of such a suitable material is ductile iron. Although ductile iron is not easily welded to steel, such a flight can be attached to the pins by an adhesive, as described above. Such a flight may have a construction similar to the flight  418  (e.g., with openings for the pins  434  and with generally the same outer shape). Alternatively, the flight may have a construction similar to that shown in U.S. Patent Application Publication No. US 2009/0250318 A1, published Oct. 8, 2009, the entire contents of which is hereby incorporated by reference. 
     Thus, the invention may generally provide, among other things, a chain flight assembly with sound dampening. One or more independent features and advantages of the invention may be set forth in the following claims.