Abstract:
A conveyor chain includes a plurality of chain links connected together in a chain, each including a pair of forward arms having a space therebetween and a rearward arm extending in a rearward direction. The forward arms of one link are configured to receive the rearward arm of an adjacent link to form a continuous chain. The rearward arm of each link extends a distance from the forward arms so that when adjacent links are coupled together, an engagement space is created between the forward arms of the links. The engagement space is configured to receive portions of sprockets that would engage the forward arms of the link for driving the chain.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 10,398,387, filed Apr. 7, 2003, entitled, “CONVEYOR CHAIN FOR MINING MACHINERY”, which is a U.S. National Filing Phase of PCT/US2001/31746, filed Apr. 11, 2002, entitled, “CONVEYOR CHAIN FOR MINING MACHINERY”, which is a PCT Application of U.S. Provisional Patent Application No. 60/238,877 filed Oct. 6, 2000, entitled, “CONVEYOR CHAIN FOR MINING MACHINERY”, which applications are incorporated herein by reference in their entireties. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates generally to conveyor chains, and, more particularly to mining machinery conveyor chain link bodies with attachments for flight arms. 
       BACKGROUND OF THE INVENTION 
       [0003]    While conveyors with which the chain of the present invention are intended to be used may have many applications, for purposes of an exemplary showing, such conveyors will be described with respect to their use in the mining industry, although their use is not intended to be so limited. 
         [0004]    Pusher-type chain conveyors, as used in the mining industry, are found both in the form of separate conveying units, and as integral parts of continuous mining machines. A typical continuous mining machine, for example, is self-propelled and is provided at its forward end with cutting means shiftable in such a way that an entry is cut in the material being mined. The entry is so sized as to permit the passage of the mining machine therethrough. Since the cutting operation is a continuous one, it is necessary to provide means to move the cut material from in front of the mining machine and to convey it out of the entry. To this end, the mining machine usually incorporates one or several conveyors in its construction, the conveyors acting successively to transport the cut material rearwardly of the machine. Frequently, the mining machine further incorporates a “tail conveyor” which is a part of the mining machine, located at its rearward end. The purpose of the tail conveyor is to deliver the cut material to other conveying means by which it is removed from the entry. The other conveying means may comprise mine cars, portable belt conveyors, or the like. 
         [0005]    The most frequently encountered form of tail conveyor, in association with a continuous mining machine, comprises a section of conveyor base means mounted on the mining machine body. One or more additional sections of conveyor base means are connected thereto end-to-end, and extend beyond the rearward end of the mining machine body. All of the base means sections are characterized by a bottom portion provided with longitudinally extending, upstanding side guides or flanges. In order for the tail conveyor to perform its task properly, the various sections thereof must be capable of both lateral and vertical movement with respect to each other. This enables the cut material to be delivered to a desired point despite changes of position of the mining machine as it advances in the entry and changes in level of the entry floor. Similarly, this lateral and vertical movement capability of the conveyor sections enables the shifting of the desired delivery point for the material being mined, as required. 
         [0006]    The tail conveyor typically incorporates a continuous pusher-type conveyor chain which is driven along the length of the conveyor base sections. The chain is normally provided with a plurality of rigid pusher elements, normally extending substantially transversely of the conveying direction. The pusher elements are located at spaced intervals along the chain. Adjacent pusher elements are joined together by a series of alternate block-like links and plate-like links. At one end of the machine&#39;s conveyor, the continuous chain passes over a driven sprocket. At the other end of the conveyor, the chain passes over a driven or idler sprocket, or roller. 
         [0007]    Typically in the underground mining industry, machine downtime is very expensive. Should a conveyor chain fail (due to sudden impact or wear), the chain often would come apart during production causing several hours of expensive and unproductive downtime while the chain was repaired. Most often a conveyor chain fails from impact loads on the flight arms. These impacts over time cause a fracture which then causes the welded-in pins to fail. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The accompanying drawings incorporated in and forming a part of the specification illustrates several aspects of the present invention, and together with the description and claims serves to explain the principles of the invention. In the accompanying drawings: 
           [0009]      FIG. 1  is a semi-diagramatic plan view of a typical continuous mining machine having a tail conveyor utilizing a pusher-type conveyor chain; 
           [0010]      FIG. 2  is a top plan view of one embodiment of the preferred chain connector link of the present invention; 
           [0011]      FIG. 3  is a side elevational view of the connector link of  FIG. 2 ; 
           [0012]      FIG. 4  is a top plan view of one embodiment of the flight arm chain connector link of the present invention; 
           [0013]      FIG. 5  is a side elevational view of the flight arm chain connector link of  FIG. 4 ; 
           [0014]      FIG. 6  is an end view of the flight arm chain connector link of  FIG. 4 ; 
           [0015]      FIG. 7  is a top plan view of another embodiment of the flight arm chain connector link of the present invention; 
           [0016]      FIG. 8  is a side elevational view of the flight arm chain connector link of  FIG. 7 ; 
           [0017]      FIG. 9  is an end view of the flight arm chain connector link of  FIG. 7 ; 
           [0018]      FIG. 10  is a top plan view of one embodiment of the flight arm of the present invention; 
           [0019]      FIG. 11  is a side elevational view of the flight arm of  FIG. 10 ; 
           [0020]      FIG. 12  is an end view of the flight arm of  FIG. 10 ; 
           [0021]      FIG. 13  is a top plan view of another embodiment of the flight arm of the present invention; 
           [0022]      FIG. 14  is a side elevational view of the flight arm of  FIG. 13 ; 
           [0023]      FIG. 15  is an end view of the flight arm of  FIG. 13 ; 
           [0024]      FIG. 16  is a perspective view of a segment of one embodiment of the improved conveyor chain of the present invention; 
           [0025]      FIG. 17  is a top plan view of a segment of the improved conveyor chain of the present invention shown in a curved configuration; 
           [0026]      FIG. 18  is a perspective view of a segment of the improved conveyor chain of the present invention using both preferred embodiments of flight arm connector links and flight arms; and 
           [0027]      FIG. 19  is a side view of the preferred elongated sprocket of the present invention showing a segment of the improved conveyor chain of the present invention being driven thereon. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    For a better understanding of the invention, reference is first made to  FIG. 1 , illustrating an exemplary environment for the chains of the present invention.  FIG. 1  diagrammatically illustrates a typical continuous mining machine generally indicated at  2  and provided with a tail conveyor, generally indicated at  3 . The mining machine has a body portion  4  which is usually mounted on wheels or treads and is self-propelled. At the forward end of the mining machine, cutting means are provided as shown at  5  and  6 . These cutting means  5  and  6  may take various well known forms and are mounted on means such as the frame  7 , enabling the cutting means to be shifted in such a way that they will cut an entry large enough to receive and to permit advancement of the mining machine  2  in the cutting direction indicated by arrow A. 
         [0029]    By various well known conveying means, the cut material at the forward end of the mining machine is gathered and transported over or through the mining machine to the tail conveyor  3 . This last mentioned conveyor comprises a conveyor base means, illustrated in  FIG. 1  as made up of two sections  8  and  9 . The base means section  8  has a bottom portion  10  and upstanding side guide or flanges  11  and  12 . Similarly, the section  9  has a bottom portion  13  and upstanding side guides or flanges  14  and  15 . The section  9  is mounted on a boom  16  articulated to the rearward end of the mining machine body  4  as at  17 . The articulation is such that the boom  16  and its conveyor base means section  9  are shiftable with respect to the conveyor base means section  8  both in the vertical plane and the horizontal plane for reasons explained above. A pusher-type conveyor chain, generally indicated at  18 , extends along the length of the conveyor base means sections  8  and  9  and is adapted to be driven along the upper surface of their bottom portions  10  and  13 . It will be understood that the chain  18  is a continuous chain. Normally it will be driven by a sprocket at least one end of the tail conveyor  3 . 
         [0030]    As shown in  FIG. 1 , a typical chain  18  is provided with a plurality of spaced pusher elements  19 , extending substantially transversely of the conveying direction indicated by arrow B. It will be seen that the pusher elements preferably extend to both sides of the chain  18  and that the pusher elements are located at predetermined intervals along the length of the chain. 
         [0031]    To assure a thorough understanding of the chains of the present invention, the individual parts used to make up the chains will be next described in detail. Reference is first made to  FIGS. 2 ,  3  and  4  in which an exemplary chain connector link of the present invention is generally indicated at  20 . In all of the figures, like parts have been given like index numerals. 
         [0032]    As best shown in  FIGS. 2 and 3 , the improved conveyor chain of the present invention includes a plurality of generally “Y-shaped” chain connector links  20 . Each chain connector link  20  preferably includes a pair of spaced forwardly extending arms  21  and a single rearwardly extending arm  22 . A space  23  is provided between each pair of forwardly extending arms  21  that is adapted to receive a rearwardly extending arm  22  of an adjacent chain connector link  20 . Preferably, as shown in  FIG. 2 , space  23  is partially defined by a portion  24  of the chain connector link  20  of substantially semi-circular or arcuate cross section. More preferably, each forwardly extending arm  21  includes a chamfered or rounded inner edge  25 . 
         [0033]    According to an important aspect of the present invention, each rearwardly extending arm  22  includes an elongated hole  26  disposed transversely therethrough. Preferably, as shown in  FIGS. 2 and 3 , the elongated hole  26  is preferably of oblong or elliptical cross-section. More preferably, the elongated hole  26  includes a center portion  27  of a lesser diameter than either end portion  28  of the elongated hole. 
         [0034]    Each forwardly extending arm  21  includes a transverse opening  29  that is aligned with the transverse opening  29  on the corresponding forward arm  21 . Preferably, the transverse openings  29  of the forward arms  21  are substantially of circular cross section. As best shown in  FIG. 16 , and in order to secure a pair of adjacent chain connector links  20  together, a bearing pin  30  is inserted through the transverse openings of the forward arms of one chain link body and through the rearwardly extending arm of another chain link body. The bearing pin is preferably held in place by one or more retaining pins  31  inserted in corresponding retaining pin holes  32  disposed in the forward arms  21  and the bearing pins  30 . 
         [0035]    As can best be seen in  FIG. 2 , each forwardly extending arm is at least partially of substantially elliptical cross section. Preferably, the distal end of the rearwardly extending arm includes a rounded end  33 . 
         [0036]    As best shown in  FIGS. 4-6 , the improved conveyor chain of the present invention includes a plurality of flight arm connector links  34 . Each flight arm connector link  34 , similar to each chain connector link  20 , preferably includes a pair of spaced forwardly extending arms  21  and a single rearwardly extending arm  22 . A space  23  is provided between each pair of forwardly extending arms  21  that is adapted to receive a rearwardly extending arm  22  of an adjacent flight arm chain connector link  34 . Preferably, as shown in  FIG. 4 , space  23  is partially defined by a portion  24  of the flight arm chain connector link  34  of substantially semi-circular or arcuate cross section. More preferably, each forwardly extending arm  21  includes a chamfered or rounded inner edge  25 . 
         [0037]    Similar to the elongated holes  26  of the chain connector links  20 , each rearwardly extending arm  22  of the flight arm connector links  34  also includes an elongated hole  26  disposed transversely therethrough. Preferably, as described previously, the elongated hole  26  is preferably of oblong or elliptical cross-section. More preferably, the elongated hole  26  includes a center portion  27  of a lesser diameter than either end portion  28  of the elongated hole. Optionally, and as shown in  FIGS. 4 and 6 , the elongated hole  26  may be substantially of circular cross-section. 
         [0038]    Preferably, and as described previously, each forwardly extending arm  21  includes a transverse opening  29  that is aligned with the transverse opening  29  on the corresponding forward arm  21 . Preferably, the transverse openings  29  of the forward arms  21  are substantially of circular cross section. As best shown in  FIG. 16 , and in order to secure a flight arm connector link  34  with an adjacent chain connector link  20  together, a bearing pin  30  is inserted through the transverse openings of the forward arms of one chain link body  20  and through the rearwardly extending arm of another chain link body  20  or flight arm connecting link  34 . The bearing pin is preferably held in place by one or more retaining pins  31  inserted in corresponding retaining pin holes  32  disposed in the forward arms  21  and the bearing pins  30 . 
         [0039]    As best shown in  FIGS. 4 and 5 , each flight arm connector link  34  includes a pair of laterally extending flight arm attachment projections  35  adapted to receive a corresponding flight arm. Preferably, each laterally extending flight arm attachment projection  35  includes at least one, and preferably a pair of, flight arm securing holes  36 . Preferably, the each securing hole  36  extends from a front face  37  of the flight arm attachment projection  35  to a rear face  38  thereof. As can be seen in  FIG. 6 , the widths of each flight arm attachment projection  35  is substantially identical to that of adjacent arms  21  and  22 . 
         [0040]    In an alternate embodiment of the flight arm connecting link  34   a , and as best shown in  FIGS. 7-9 , the flight arm securing holes are disposed from a top surface  39  of a flight arm attachment projection  35  throughwardly to a bottom surface  40  thereof. In this embodiment, and as shown in  FIG. 9 , the flight arm attachment projections  35  are of a width less than adjacent arms  21  and  22 . 
         [0041]    Reference is made to  FIGS. 10-12  wherein one embodiment of a flight arm  41  is shown. Preferably each flight arm includes an elongated body  42  having a flat, planar bottom surface  43 . The body  42  has a central rib or web  44  acting as a pusher for the material being conveyed. The outer free end of the flight arm  41  is provided with a knob-like portion  45  which can ride against side guide elements  11 ,  12 ,  14  and  15  associated with conveyor sections  8  and  9 . A chain link connecting portion  46  is provided with a recess  47  to facilitate attachment to a corresponding flight arm attachment projection  35  of a flight arm connecting link  34 . The chain link connecting portion is provided with opposing prongs  48  having bearing holes  49  disposed therethrough. Bearing holes  49  are adapted to match up with corresponding flight arm securing holes  36  of a corresponding flight arm attachment projection  35  of a flight arm connector link  34 . Bearing pins may be inserted through holes  36  and  49  to attach components  34  and  41  together. Bearing pins may be held in place by retaining pins disposed though retaining pin holes  51  and  32  of the flight arm  41  and flight arm connecting link  34  respectively. The embodiment of the flight arm  41  shown in  FIGS. 10-12  is particularly adapted for use with the embodiment of the flight arm connecting link  34  of  FIGS. 10-12 . 
         [0042]    Various other methods of flight arm attachments to the flight arm attachment link  34  are possible other than the bearing and retaining pin assemblies described. For example, the flight arm may be doweled, bolted, keyed or interlocked to a corresponding link various ways as known in the art. One advantageous feature of the above described designs of the present invention is the separation of the flight arms from the main bearing pin  30 . The separation of the flight arms  41  from the main bearing pins  30 , allows for better quality steels to be used without compromising the main bearing pins  30  toughness and fracture resistance in order to have good weldability (a requirement of prior art designs). 
         [0043]    It should be appreciated that the various components may be comprised of essentially any suitable material known in the art that exhibits the requisite strength and durability characteristics. The various components are preferably steel and may be forged or are more preferably cast. Preferably the flight arms are comprised of spring steel. In order to reduce noise levels further during operation, composite steel and plastic or urethane components may be used. 
         [0044]    A similar flight arm embodiment  41 A with differently oriented bearing holes  49  and opposing prongs  48  is shown in  FIGS. 13-15 . Flight arm  41 A is adapted for use with and connection to the embodiment  34 A of the flight arm connecting link shown in  FIGS. 7-9 . 
         [0045]    As can be seen in the  FIGS. 16-18 , the complete chain will be comprised of both “Y-shaped” chain connector links  20  and flight arm attachment links  34  or  34 A with flight attachments  41  or  41 A fixedly disposed thereon. Preferably each elongated hole  26  is adapted to “loosely” receive the bearing pin  30  so as to permit articulation and to allow, as a result, the conveyor chain of the present invention to navigate curves (See  FIG. 17 ). It should be appreciated that the chain has the ability to negotiate curved conveyor sections by articulating via the elongated hole  26  through which the bearing pin  30  has freedom to “rotate” about the chain center and allow the chain the flexibility it needs to travel through the curved section. This offers a distinct advantage over known prior art chains which incorporate welded-in main bearing pins. The main bearing pin  30  preferably has an interference fit or may have a slight rotating fit in the transverse openings  29  of the forward arms  21  of the chain connector links  20 . Depending upon its orientation in use, the links  20 ,  34 , and  34 A will preferably ride along the upper surfaces of the bottom portions  10  and  13  of conveyor sections  8  and  9  either on its surfaces  30  and  31  or its surfaces  33  and  34 . 
         [0046]    As can be seen in  FIG. 19 , the improved chain of the present invention is preferably driven by a six tooth dual sprocket  52 . The chain is preferably designed with an offset in pitch from forward to reverse to allow for the chain to be seated in a corresponding sprocket root  53 . Advantageously, this configuration allows for the chain to remain engaged longer on the sprocket and to be conveyed directly onto a loading deck. This configuration serves to minimize interference with loading devices and improves both sprocket and chain life. The dual six tooth sprocket also reduces the chains “striking energy” advantageously reducing chain drive noise. 
         [0047]    The foregoing description of a preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described in order to best illustrate the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.