Abstract:
The invention relates to an advancing tailpiece of a continuous belt conveyor system used in the mining industry. The advancing tailpiece is supported by telescopic booms extending from a support structure rising from the base of a tow car. The telescoping booms are pivotally connected to the support structure and the advancing tailpiece. The advancing tailpiece further includes a mechanical arm pivotally connected to the advancing tailpiece and having a telescopic boom. Carrying idler assemblies are loaded on the mechanical arm which is used to position the carrying idler assembly for attachment to an intermediate conveyor section of the continuous belt conveyor.

Description:
FIELD OF THE INVENTION 
     The present invention relates to continuous belt conveyor systems used in the mining industry, and particularly to an advancing tailpiece. 
     BACKGROUND OF THE INVENTION 
     Mining tunneling operations typically include a tunnel boring machine which cuts and fractures the rock and produces muck material. A transfer conveyor is towed by the tunnel boring machine. The transfer conveyor removes the muck material from the tunnel boring machine and usually conveys the muck material up and over to one side of the tunnel. The muck material is discharged to a receiving hopper of an advancing tailpiece which is also towed by the tunnel boring machine. The muck material is then loaded onto a continuous belt conveyor. 
     The support structure of the continuous belt conveyor is secured to the tunnel. However, the continuous belt conveyor must extend or advance with the advancing tunnel boring machine. The advancing tailpiece makes possible the advancing of the continuous belt conveyor. The advancing tailpiece is usually supported by one of the vehicles which is towed by the tunnel boring machine. The end loop of the belt is carried by a pulley of the advancing tailpiece. As the advancing tailpiece advances, the belt length gets longer as it is pulled out of a belt storage system, typically near the discharge end of the belt conveyor. The belt storage system is usually a cluster of pulleys which can be moved to allow the continuous belt conveyor to extend. 
     As the advancing tailpiece advances, the distance increases between the support structure of the conveyor and the pulley of the tailpiece, as well as the belt spanning therebetween. As the advancing tailpiece advances, return rolls are secured to the continuous belt conveyor system. The return rolls support the belt during the belt return path at the bottom of the continuous belt conveyor. Carrying idler assemblies must also be installed within the loop of the belt to support the belt during the load carrying portion of the path of the belt. The carrier idler assemblies must be installed through the frame of the tailpiece. The carrying idler assemblies are installed by workers on a frame of the continuous belt conveyor, typically using J-bolt/loop-nut arrangements. The carrying idler assemblies and return rolls form the support structure of the continuous belt conveyor. The carrying idler assemblies do not move with the advancing tailpiece and so they must be installed prior to the advancing tailpiece advancing beyond the distance the belt can be supported by the last installed carrying idler assembly and the advancing tailpiece. 
     To accommodate the worker, the frame of the tailpiece must include an access opening for the worker to climb into the advancing tailpiece to install the carrying idler assembly. The tailpiece typically includes 3 or 4 belt pulleys such as shown in U.S. Pat. No. 4,890,720. The number of pulleys, in part, dictates the size of the advancing tailpiece. The larger the tailpiece, the less space is available in the tunnel adjacent the tailpiece. This is an important consideration because in small bore diameter tunnels, for example, 10 foot to 11 foot diameter, the area where the advancing tailpiece is located becomes very congested as tunnel supply trains must pass by the advancing tailpiece, and due to other tunneling operation support functions that must be carried out in this area such as ventilation, dust collection, water pumps, electrical transformers, and tunnel structural support erection equipment. 
     The tow vehicle typically rides on steel rails or slides on skid rails and is towed by the mining machine. The movement of this vehicle as it is towed will not be an accurate line, therefore, in order to keep the advancing tailpiece located accurately on the belt centerline, there must be some method of moving the advancing tailpiece relative to the support car. 
     This is accomplished in the prior art with two horizontal extension booms to provide for lateral movement, two vertical tracks to provide vertical movement and two tilt cylinders to control the roll of the tailpiece about a longitudinal axis. 
     SUMMARY OF THE INVENTION 
     It is an object of the present prevention to provide an advancing tailpiece having a reduced dimension over the prior art. 
     It is a further object of the present invention to provide an advancing tailpiece having an improved method of installing carrying idlers. 
     It is still a further object of the present invention to provide an advancing tailpiece having an access opening for installing carrying idlers of reduced dimensions over the prior art. 
     It is yet a further object of the present invention to provide an advancing tailpiece which does not require a vertical track to provide for vertical movement. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a part cross sectional, part plane view of an advancing tailpiece of the present invention, within a tunnel and supported by a tow vehicle; 
     FIG. 2 is a part cross sectional, side view and part plan sideview of the tailpiece of FIG. 1; 
     FIG. 3 is a part cross sectional top view and part plan top view of the advancing tailpiece of FIG. 1; and 
     FIG. 4 is a plan view of a carrying idler assembly. 
    
    
     DETAILED DESCRIPTION OF INVENTION 
     Referring to FIG. 1, the advancing tailpiece  10  is shown to be supported by a tow vehicle  12 . The tow vehicle  12  is typically one of several vehicles towed by the tunnel boring machine (not shown) along rails  13 . The tow vehicle  12  includes a column or vertical structure  14  by which the advancing tailpiece  10  is supported by way of first telescope boom  16 . FIG. 3 discloses a second telescoping boom  18 , which is coupled to a further vertical structure (not shown). 
     The first ends  20  of the first and second telescoping boom  16 ,  18  include bushings  22 , for pivotal connection to the respective vertical structure with pins  23 . The second ends  24  of the first and second telescoping booms  16 ,  18  similarly including bushings  22  and pins  26  for pivotal connection to the frame  28  of the advancing tailpiece. 
     As seen in FIG. 1, the advancing tailpiece is also supported by the tow vehicle  12 , by way of a vertical elevating cylinder  30  having a first end  32  pivotally connected with pin  33  to the tow vehicle  12  and a second end  34  pivotally connected with pin  35  to the frame  28  of the advancing tailpiece  10 . 
     The first telescoping boom  16  includes an outer boom portion  36 , and an inner boom portion  38 . The second telescoping boom  18  also includes an outer boom portion  40  and an inner boom portion  42 . 
     The inner boom portion  38  of the first telescoping boom  16 , includes a leverage or extension portion  44 , having a distal end  46 . A tilt cylinder  48  includes a first end  50  having a pin  52  for pivotal connection to the distal end  46  of the extension portion  44 . The tilt cylinder  48  includes a second end  54  having a pin  52  for pivotal connection to the frame  28 , of the advancing tailpiece  10 . 
     The outer boom portions  36 ,  40  include flanges  55  and longitudinally extending slots  56 . Telescoping cylinder  58  includes first end  60  secured to respective flanges  55 , and second end  62  mounted to flanges  64  of the inner boom portions  38 ,  42 . The flanges  64  extend within the slots  56  of the outer boom portions  36 ,  40 . 
     The outer boom portions  36 ,  40  include guide flanges  66 , having guide rollers  68 . The guide rollers  68  protrude through window  70  of the outer boom portions  36 ,  40  to engage the inner boom portions  38 ,  42  to guide the movement of the inner boom portions  38 ,  42  within the outer boom portions  36 ,  40 . 
     FIG. 3 discloses a first connecting bar  72 , connected between the first and second telescopic booms  16 ,  18  parallel to the longitudinal axis of the frame  28 . The first connecting bar  72 , includes a first end  74  connected to the outer boom portion  40  and a second end  76  connected to the outer boom portion  36 . A second connecting bar  78  is connected between the first and second telescoping booms  16 ,  18 , and angularly displaced with respect to the first connecting bar  72 . The second connecting bar  78  includes a first end  80  connected to the outer boom portion  40  and a second end  82  connected to the outer boom portion  36 . 
     FIG. 2 shows the belt  84  having a load portion  86  and a return portion  88 . The belt  84  is part of the belt conveyor intermediate section (not shown). The intermediate section includes a plurality of spaced apart carrying idler assemblies  92  such as shown in FIG.  4 . The carrying idler assembly  92 , includes flanges  91 ,  93  and rollers  94 . The rollers  94  are arranged so that as the belt  84  advances along the carrying idler assemblies  92 , the belt  84  forms a trough to retain crushed rock and the like. The intermediate section (not shown) includes return rollers  95  (FIG. 2) which support the belt  84 , along the return portion  88 . The belt  84  is coupled to the advancing tailpiece  10  by way of the tail pulley  90 . The belt  84  is supported by a straight roller  96 . The belt  84  is flat along the load portion  86  between the straight roller  96  and the pulley  90 . At portion  98  the belt  84  begins to take the shape of a trough as it moves closer to the first carrying idler assembly of the intermediate section (not shown). At portion  98  of the belt  84 , the hopper  100  is located for receiving crushed rock and other muck material from the transfer conveyor (not shown) of the tunnel boring machine (not shown). To prevent the belt  84  from being damaged as the hopper  100  and belt  84  receive the crushed rock, trough-shaped steel plates  102  are located beneath the belt  84 . With reference to the view shown in FIG. 2, the trough-shaped steel plates  102  provide a shallow bottom adjacent the straight roller  96 . The bottom of the trough-shaped steel plates  102  increases gradually in depth as the plates  102  extend away from the straight roller  96 . Another view of the steel plates  102  is shown in FIG.  1 . 
     It is important to note that the required diameter of the single tail pulley  90  is no larger than what would normally be used at the receiving end of the belt conveyor if a standard fixed or non advancing tailpiece were used. 
     A rectangular access opening  104  is provided in the side of the frame  28  from which extends a mechanical arm  105 . The mechanical arm  105  is shown in various extended positions in phantom lines. The mechanical arm  105  includes an upper bracket  106  and a lower bracket  108  which are secured to the frame  28 . A column  110  is pivotally mounted to the upper and lower brackets  106 ,  108  for rotation about a vertical axis. A cylinder  111  shown in FIG. 3 is coupled to the mechanical arm  105  and is stroked to rotate the mechanical arm  105  about a vertical axis of the column  110 . A telescopic boom  112  includes a first end  113  pivotally secured to the column  110  by a U-shaped bracket  114  and pins  116  to allow the telescoping boom  112  to be raised and lowered by a cylinder  118 . The cylinder  118  includes a first end  120  pivotally coupled to an extended portion  122  of the column  110 , and a second end  124  pivotally coupled to the telescoping boom  112 . The telescoping boom  112  includes a first boom  126  and a second boom portion  128 . The second end  130  of the telescoping boom  112 , includes a cradle  132  for receiving a carrying idler assembly  92 . The cradle  132  includes a transverse portion  134  from which extends prongs  136 . 
     The advancing tailpiece  10  of the present invention operates as follows. As the tailpiece  10  advances forward, the belt storage (not shown) effectively increases the length of the belt  84  as the tail pulley  10  advances. In order to support the belt  84  at the return portion  88 , the return roller  95  (see FIG. 2) is secured to the intermediate section (not shown) and below the advancing tailpiece  10 . In addition, a further carrying idler assembly  92  is installed through the access opening  104  of the advancing tailpiece  10 . Each return roller  95  and carrying idler assembly  92  must be installed before the advancing tailpiece  10  advances to a point where the intermediate section (not shown) and the advancing tailpiece  10  are no longer able to support the portion of the belt  84  suspended between the intermediate section (not shown) and the advancing tailpiece. 
     The mechanical arm  105  is positioned at the location as shown in FIG. 3 in solid lines, and the carrying idler assembly  92  is positioned onto the cradle  132  of the mechanical arm  105 . The mechanical arm  105  is then positioned at the location shown in FIG. 3 in phantom lines. The mobility of the mechanical arm  105  allows the carrying idler assembly  92  (see FIG. 4) to be placed with the pin  138  extending through the hole  140  of the flange  91 . The pins  138  extend from the intermediate section (not shown) in spaced apart relation corresponding to the positions the carrying idler assemblies  92  are to be installed. The mechanical arm  105  is then retracted away from the carrying idler assembly  92  and the J-bolt and loop nut are secured to the flange  93  of the carrying idler assembly  92 . The present invention allows moving the advancing tailpiece  10  relative to the tow vehicle (not shown) to provide a new method of maintaining the advancing tailpiece  10  located accurately on the belt center line. The telescoping booms  16 ,  18  provide for lateral movement of the advancing tailpiece  10 . The cylinder  48  controls the roll of the tailpiece  10  about a longitudinal axis. The vertical movement is accomplished by pivotally mounting the telescoping booms  16 ,  18  at the ends so that the telescoping booms  16 ,  18  can swing in an arc, as dictated by the cylinder  30 .