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. Patent 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 two 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 invention 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 the 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 for 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 two vehicle 12, by way of a vertical elevating cylinder 30 having a first end 32 pivotally connected with pin 33 to the two 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 38,42.

FIG. 3 discloses a first connecting bar 72, connected between the first and second telescopic boom 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 boom 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 position 86 and a return position 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. The carrying idler assembly 92, includes flanges 91,93 and rollers 94. The rollers 94 are arranged to 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 position 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. As position 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 position 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 position 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. The return roller 95 and carrying idler assembly 92 must be installed before the advancing tailpiece 10 advances beyond the intermediate section (not shown) and tailpiece 10 capability to support the belt 84 therebetween.

The mechanical arm 105 is positioned to 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 to the location shown in FIG. 3 in phantom lines. The mobility of the mechanical arms 105 allows the carrying idler assembly 92 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.