Abstract:
A chain link assembly, a cable chain assembly and a mining system. The cable handler individual links may include an enclosed section for the fiber optic cable separate from other services for the machine. A flexible material or other structure may assemble the fiber optic cable in the cable handler in a manner in which it “snakes” about the centerline to provide ample slack in the fiber optic cable to, for example, prevent over tension.

Description:
FIELD 
     The present invention relates to longwall mining and, more particularly, to a cable handler chain in a longwall mining installation. 
     SUMMARY 
     A longwall shearer traverses along an armoured face conveyor (AFC) pan line to win material from the face. The operation of the shearer requires electrical power for cutting and tramming as well as water for cooling machine components including electric motors and gearcases. These services are provided out-bye the longwall face and must travel along the AFC to reach the shearer. Typically, these services lay statically along the AFC until the mid point of the face where the services typically enter the cable handling system which runs in a trough to the shearer towing bracket. The towing bracket is attached to the shearer and pulls the cable handler, with services inside, along the trough. The cable handling system is designed to withstand tension caused from the weight of the system and friction as it is being towed down the cable trough, protecting the services which are not designed to withstand these forces. 
     The services provided to the shearer typically include only electric cables and water hoses. However, fiber optics is becoming increasingly appealing as a way to, for example, provide an unmanned face in low seam longwall mining installations or even in high seam mining. Fiber optic cores are used for high speed single- and two-way communication between the shearer and the off-face equipment. The information consists of system I/O, diagnostic information, radio control and video transmission. If fiber optic cables are used for such communications, reliability of the fiber optic cores is important. The maximum tensional load for the fiber optic cores is considerably lower than all other cables being routed to the shearer. 
     The illustrated constructions may provide a reliable means of transmitting the data by protecting the fiber optic cable from over tension and failure. Reliability is important as significant downtime results in lost production and revenues of the mine, and, because of difficult ergonomic conditions associated with low seam longwall mining, repairs are difficult. 
     In order to ensure the reliability of the fiber optic cable, the fiber optic cable may be placed in a separate compartment within the cable chain. This separate compartment may be formed by adding a divider to the chain link to create two different compartments, one for the electrical power cable/water hose and a much smaller one for the fiber optic cable. A compressible material may provide a means to assemble the fiber cable in such a way to ensure adequate slack exists over the entire length of the cable chain to prevent over tension and failure. 
     The separate compartment may ensure that the other larger lines cannot damage the fiber optic cable by sliding up against and over tensioning and wearing the fiber cable due to friction. The separate compartment may also provide means of constraining the compressible material in all degrees of freedom. 
     In one independent embodiment, a chain link assembly may generally include a chain link having a plurality of walls cooperating to define a compartment opening in the direction of the axis, a fiber optic cable being supportable in the compartment, a service line (e.g., a power cable, a water hose, etc.) being supportable in the compartment, and a flexible member supported in the compartment and engageable with the fiber optic cable, the flexible member positioning the fiber optic cable toward one of the plurality of walls. 
     In some constructions, the flexible member may include a compressible member supported on an opposite one of the plurality of walls. The compressible member may include a substantially solid member formed of compressible material. The compressible member may include a hollow member having a first portion engageable with the fiber optic cable and a second portion spaced from the first portion and engaging the opposite one of the plurality of walls. The hollow member may have a substantially tubular cross section. The compressible member may include a leaf spring. In some constructions, the flexible member may be connected to the one of the plurality of walls and extends at least partially around the fiber optic cable, the flexible member being in tension towards the one of the plurality of walls. 
     In some constructions, the chain link may further include an internal wall dividing the compartment into a first compartment and a second compartment, the fiber optic cable being supportable in the first compartment, the service line being supportable in the second compartment. The internal wall may extend between the one of the plurality of walls and an opposite one of the plurality of walls to define the first compartment on one side of the internal wall and the second compartment on the other side of the wall. The internal walls may be formed with the one of the plurality of walls and an opposite one of the plurality of walls. 
     The internal wall may be separate from and connected to the one of the plurality of walls and an opposite one of the plurality of walls. One of the plurality of walls may define a first groove, and the opposite one of the plurality of walls may define a second groove. The internal wall may include a first projection engageable in the first groove and a second projection engageable in the second groove to connect the internal wall to the one of the plurality of walls and to the opposite one of the plurality of walls. The internal wall may include a connecting member, a portion of the flexible member being captured between the connecting member and an opposite one of the plurality walls. 
     The flexible member may have a surface engageable with the fiber optic cable, the surface including a low friction material. The surface may be coated with the low friction material. The flexible member may have a surface engageable with the fiber optic cable, the surface having curved edges. 
     In another independent aspect, a cable chain assembly may generally include a plurality of chain links each having a top wall, a bottom wall, a first side wall and a second side wall cooperating to define a compartment opening in the direction of the axis, a fiber optic cable extending through the compartment in each of the plurality of chain links, the fiber optic cable extending generally along a wave-shaped path, a service line supportable in the compartment in each of the plurality of chain links, a first flexible member supported in the compartment of one of the plurality of chain links and engageable with the fiber optic cable, the first flexible member positioning the fiber optic cable toward the top wall of the one of the plurality of chain links, and a second flexible member supported in the compartment a second one of the plurality of chain links and engageable with the fiber optic cable, the second flexible member positioning the fiber optic cable toward the bottom wall of the second one of the plurality of chain links. 
     In some constructions, a third one of the plurality of chain links may be connected between the one of the plurality of chain links and the second one of the plurality of chain links, the third one of the plurality of chain links not having a flexible member in the compartment. Each of the plurality of chain links may include a pair of forward projections and a pair of rearward projections each defining an opening, and the assembly may further include a first pin connecting the rearward projections of the one of the plurality of chain links to the forward projections of the third one of the plurality of chain links, the first pin defining a pivot axis between the one of the plurality of chain links and the third one of the plurality of chain links and a second pin connecting the rearward projections of the third one of the plurality of chain links to the forward projections of the second one of the plurality of chain links, the second pin defining a pivot axis between the third one of the plurality of chain links and the second one of the plurality of chain links. 
     In yet another independent embodiment, a mining system may generally include an armoured face conveyor extending along a face to be mined, the conveyor defining a cable trough, a shearer supported by and for movement along the conveyor, the shearer being operable to mine material from the face, and a cable chain assembly extending along an axis generally parallel to the face, the assembly being partially supported in the trough. The assembly may include a plurality of chain links each having a top wall, a bottom wall, a first side wall and a second side wall cooperating to define a compartment opening in the direction of the axis, a fiber optic cable extending through the compartment in each of the plurality of chain links, the fiber optic cable extending generally along a wave-shaped path, the fiber optic cable being connected to the shearer, a service line supportable in the compartment in each of the plurality of chain links, the service line being connected to the shearer, a first flexible member supported in the compartment of one of the plurality of chain links and engageable with the fiber optic cable, the first flexible member positioning the fiber optic cable toward the top wall of the one of the plurality of chain links, and a second flexible member supported in the compartment a second one of the plurality of chain links and engageable with the fiber optic cable, the second flexible member positioning the fiber optic cable toward the bottom wall of the second one of the plurality of chain links. 
     Independent aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top plan view of a longwall mining system including an Armoured Face Conveyor (“AFC”). 
         FIG. 2  is a top plan view of a portion of the longwall mining system shown in  FIG. 1  including the AFC, a shearer and a cable chain. 
         FIG. 3  is a profile view of a portion of the longwall mining system shown in  FIG. 1  including the AFC, the shearer and the cable chain. 
         FIG. 4  is a cross-sectional view of a portion of a cable chain of the longwall mining system shown in  FIG. 2 . 
         FIG. 4A  is a cross-sectional view of a portion of a cable chain of a longwall mining system according to another embodiment. 
         FIG. 4B  is a cross-sectional view of a portion of a cable chain of a longwall mining system according to another embodiment. 
         FIG. 5  is a perspective cross-sectional view of a portion of the cable chain shown in  FIG. 4 . 
         FIG. 6  is a side cross-sectional view of a portion of the cable chain shown in  FIG. 4 . 
         FIG. 7  is a perspective cross-sectional view of an alternative construction of the cable chain shown in  FIG. 4 . 
         FIG. 8  is a perspective cross-sectional view of another alternative construction of the cable chain shown in  FIG. 4 . 
         FIG. 9  is a perspective cross-sectional view of yet another alternative construction of the cable chain shown in  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     Before any independent embodiments or independent constructions of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other independent embodiments and of being practiced or of being carried out in various ways. 
     A longwall mining system  10  is illustrated in the  FIGS. 1-3 . The system  10  may be used in mines having a low seam or a high seam. The system  10  generally includes an Armoured Face Conveyor (AFC)  14  extending along a face F to be mined (e.g., a coal block). A shearer  18  is supported on and traverses on the pan line  22  (see  FIG. 3 ) of the AFC  14  to win material from the face F. Head and tail drives  26 ,  30  (see  FIG. 1 ) move the conveyor of the AFC  14  to convey mined material (e.g., coal). The length of this system  10  is typically around 1000 feet. 
     As shown in  FIGS. 2-3 , the AFC  14  includes a cable trough  30  extending along an axis A generally parallel to the face F. A cable chain  34  is positioned in the cable trough  30  and extends generally along the axis A. As shown in  FIG. 4 , service lines (e.g., electrical power cables  38 ,  42 , water hose  46 ) and a fiber optic cable  50  are supported in the cable chain  34 . 
     As shown in  FIGS. 5-6 , the cable chain  34  is formed from a plurality of chain links  54   a ,  54   b ,  54   c  . . .  54   n . Each chain link  54  generally includes (see  FIGS. 4-5 ) a plurality of walls (e.g., a top wall  58 , a bottom wall  62  and opposite side walls  66 ,  70 ) defining a link compartment  74  opening in the direction of the axis A. Each chain link  54  also includes (see  FIGS. 5-6 ) a set of forward and rearward projections  78 ,  82 , each defining an opening  86  for receiving a pin (not shown) to connect the chain links  54  into a chain (see  FIGS. 5-6 ). 
     In the illustrated construction and in some independent aspects, each chain link  54  also includes an internal divider wall  90  dividing the link compartment  74  into a first compartment  94 , for the fiber optic cable  50 , and a second compartment  98 , for the service lines ( 38 ,  42 ,  46 ). Each compartment  94 ,  98  is generally rectangular with the first compartment  94  being relatively narrow in a horizontal direction (see  FIG. 4 ). In other constructions (not shown), the compartment(s)  94 ,  98  may have a different shape (e.g., square, round, oval, etc.) and/or size. 
     In the construction shown in  FIGS. 4-6  and  9 , the divider wall  90  is formed with the other walls ( 58 ,  62 ) of the chain link  54 . In other constructions (see, for example, FIGS.  4 B and  5 - 8 ), the divider wall  90  is separate from the chain link  54  and connected to the top and bottom walls  58 ,  62  by inter-engaging connecting members ( FIG. 4B ) such as, for example, keying projection(s) and groove(s) on the divider wall  90  and on the walls  58 ,  62 . The connecting members cooperate to retain the divider wall  90  in position. In such constructions, the walls  58 ,  62 ,  66 ,  70  of the chain link  54  may also be formed separately from one another and connected by interengaging connecting members with a friction fit, pinned, etc. 
     In the illustrated construction and in some independent aspects, in at least some of the chain links  54 , a flexible member  102  is provided in the first compartment  94  and engages the fiber optic cable  50 . Flexible members  102  are arranged along the cable chain  34  to provide a non-linear (e.g., wave-shaped) path P for the fiber optic cable  50  such that there is slack in the fiber optic cable  50  (the length of the fiber optic cable  50  in the cable chain  34  is greater than the length of the cable chain  34 ). 
     The flexible member  102  may support and locate the fiber optic cable  50  in the first compartment  94 . The surface  106  of the flexible member  102  engaging the fiber optic cable  50  includes a low friction material (e.g., the flexible member  102  may be formed of low friction material and/or the surface  106  may be coated with low friction material (e.g., a slippery coating)) to limit the coefficient of friction between the flexible member  102  and fiber optic cable  50  thereby limiting the extension of the fiber optic cable  50  along its axis as the fiber optic cable  50  is tensioned. Also, the surface  106  and the edges/corners  110  of the flexible member  102  in the area of the fiber optic cable  50  are sufficiently curved/rounded to prevent damage to the fiber optic cable  50  when relative motion occurs between the flexible member  102  and the fiber optic cable  50 . 
     In some constructions (for example, in  FIGS. 4-6 , in  FIG. 7  and in  FIG. 8 ), the flexible member  102  includes a compressible member such that, when the fiber optic cable  50  is pulled, compression is induced in the flexible member  102 . Applying tension T on the fiber optic cable  50  causes the fiber optic cable  50  to compress the compressible member  102  in the direction of arrow D (see  FIG. 6 ). 
     In the construction shown in  FIGS. 4-6 , the flexible member  102  includes a solid compressible member  102   a  formed of, for example, foam. The compressible member  102   a  generally occupies the majority of the first compartment  94  (e.g., the remainder of the first compartment not occupied by the fiber optic cable  50 ). The compressible member  102   a  is constructed to position the fiber optic cable  50  toward one wall (e.g., the top wall  58  of the chain link  54   a , the bottom wall  62  of the chain link  54   c ). 
     In other constructions ( FIG. 4A ), the compressible member  102   a  may be constructed to at least partially encompass the fiber optic cable  50 . For example, the compressible member  102   a  may also include a portion ( FIG. 4A ) between the fiber optic cable  50  and one or both of the adjacent side walls ( 70 ,  90 ) of the first compartment  94  and/or a portion ( FIG. 4A ) between the fiber optic cable  50  and the one wall (e.g., the top wall  58  of the chain link  54   a , the bottom wall  62  of the chain link  54   c ) to at least partially fill space around the fiber optic cable  50  (see  FIG. 4 ). In constructions in which the compressible member  102   a  at least partially encompasses the fiber optic cable  50 , the compressible member  102   a  may also be sufficiently rigid such that a divider wall may not be provided to separate the fiber optic cable  50  from the service lines ( 38 ,  42 ,  46 ). 
     The compressible member  102   a  is positioned against the opposite wall (e.g., the bottom wall  62  of the chain link  54   a , the top wall  58  of the chain link  54   c ). In the illustrated construction (see  FIG. 6 ), the surface of the opposite wall is curved to match the shape of the adjacent surface of the compressible member  102   a . However, in other constructions (not shown), the surface of the opposite wall may have a different shape (e.g., linear). 
     In other constructions, the flexible member  102  includes a hollow compressible member, such as a hollow tubular member, that will allow the fiber optic cable  50  to deflect inwardly when subject to tension. As shown in  FIG. 7 , the flexible member  102  includes a hose section  102   b  (a short length of rubber hose). In a similar construction (see  FIG. 8 ), the flexible member  102  includes a leaf spring  102   c . The leaf spring  102   c  may be made of a number of materials to achieve the desired stiffness. 
     In the illustrated construction (see  FIGS. 7-8 ), the divider wall  90  includes a connector  114  (e.g., a cantilevered protrusion), and the hose section  102   b  or the leaf spring  102   c  is retained by the connector  114  (e.g., between the connector  114  and the opposite wall (e.g., the bottom wall  62  of the chain link  54   a , the top wall  58  of the chain link  54   c )). 
     In a further construction, the flexible member  102  includes a tension member, such as an elastic band  102   d . The band  102   d  is connected to the one wall (e.g., the top wall  58  of the chain link  54   a , the bottom wall  62  of the chain link  54   c ) and extends around the fiber optic cable  50 . When the fiber optic cable  50  is tensioned, taking up the slack, the band  102   d  will be pulled in tension as well. 
     The band  102   d  can be an open loop for easy assembly/disassembly and be fastened to the wall  58  or  62  of the chain link  54 . The walls  58 ,  62  are provided with recessed connecting portions  118  such that the band  102   d  is within the outer periphery of the chain link  54  (e.g., below the top wall  58  of the chain link  54   a , above the bottom wall  62  of the chain link  54   c ). Connecting the band  102   d  below flush on the outer surface of the wall  58  or  62  may protect the band  102   d  from becoming damaged, dislodged, etc. by external debris. 
     The flexible member  102  may provide one or more functions. For example, the flexible member  102  may provide a means of assembling the fiber optic cable  50  inside the cable chain  34  with a predetermined amount of slack. For example, as shown in  FIG. 5 , the fiber optic cable  50  may be forced by the flexible members  102  into a “sine wave” to “snake” about the neutral axis of the cable chain  34  around the flexible members  102 . The fiber optic cable  50  is assembled in the manner over the entire length of the cable chain  34 .  FIG. 5  shows a peak-to-valley of the fiber optic cable  50  assembled in this manner over three chain links  54   a ,  54   b ,  54   c . This frequency can easily be adjusted depending on different requirements in the system  10  as each chain link  54  will be able to accept and retain a flexible member  102 . Adequate slack in the fiber optic cable  50  accommodates the stretching of the cable chain  34  as it is subject to tension from the shearer  18 . 
     The flexible member  102  may provide a buffer, or cushion, when the fiber optic cable  50  is subject to tension. When the fiber optic cable  50  is subject to tension, the resilient property of the flexible member  102  will allow the “snaked” cable  50  to compress the material and deflect inwardly (see  FIG. 6 ), providing a means to limit over-tension and premature failure of the fiber optic cable  50 . The flexible member  102  may fill a void in the first compartment  94  that could otherwise be occupied by debris (which may accelerate wear or cause failure of the fiber optic cable  50 ). 
     Various independent features and independent advantages of the invention may be set forth in the following claims: