Patent Publication Number: US-7717650-B2

Title: Roof truss shoe having wedge retention device and method of using the same

Description:
RELATED APPLICATIONS 
   This application claims priority from earlier-filed U.S. application Ser. No. 10/725,895, filed Dec. 2, 2003, now U.S. Pat. No. 7,118,310 entitled Truss Shoe for a Mine Roof and Method. 
   FIELD OF THE INVENTION 
   The present invention relates generally to mine roof trusses typically formed using a pair of inclined bar bolts, cables, and a pair of truss shoes. More particularly, the present invention relates to a truss shoe having a wedge retention device that retains the cable-gripping wedges. 
   BACKGROUND OF THE INVENTION 
   In mining operations, bolts are often used to support the roof of the mine. In some applications, a pair of spaced apart inclined bar bolts are anchored into the roof of the mine. Each inclined bar bolt is connected to a truss shoe, which is often called a truss bracket. The truss shoes, which also are spaced apart due to their connection to the inclined bar bolts, are joined together by a pair of horizontally extending members which in turn are joined by a coupler. Typically, the horizontal member consists of a pair of generally horizontally threaded rods, with each of the threaded rods being connected to a corresponding one of the truss shoes. 
   Certain considerations may be faced when installing a mine roof truss. For example, the inclined bar bolts are typically installed using a bolting machine, and the truss shoes typically are already attached to the inclined bar bolts. The installer than installs the horizontal rods and the coupler that extend between the truss shoes. The horizontal rods may be connected to one another using a variety of couplers, such as a spacer tube or a dog bone coupler. One end of each of the threaded rods must be secured to a corresponding one of the truss shoes. After the assembly is complete, the horizontal rods are tensioned using a tensioning machine. 
   Each truss shoe has a tapered bore or barrel sized to receive an end of one of the horizontal rods, and a set of wedge pieces are placed in the bore on each one of the truss shoes. These wedge pieces grip the horizontal rod such that tension on the pair of horizontal members tends to draw the wedge pieces deeper into the tapered barrel, thus tightening the grip on the horizontal member. 
   The installer typically must ensure that the wedge pieces in each of the truss shoes are in place and have not been knocked loose or lost during any of the assembly steps. Many times, the wedge pieces must be manually placed in the tapered portion of the bore in the truss shoe. Unfortunately, these loose wedge pieces can easily fall to the ground during installation, where these small wedge pieces may be lost in the darkness of a mine passage. Of course, valuable time and effort may be expended looking for and recovering any missing wedge pieces. Even if the installer has a ready supply of replacement wedges, the installer often must expend extra time and effort inserting new wedges, which must be accomplished in the often cold and/or dark setting of a mine. 
   SUMMARY OF THE INVENTION 
   In accordance with an aspect of the invention, a truss shoe for use in a roof truss adjacent a mine roof comprises a base having a pair of ends, a curved side extending between the ends, a top side, and a bearing surface adapted to abut the mine roof. The shoe includes an angled stanchion on the top side having a first bore extending through to the bearing surface and adapted to receive an inclined bolt of the roof truss, a housing on the top side of the shoe separated from the stanchion by a recess and including a second an preferably tapered bore having a first opening adjacent an end of the housing and a having second opening disposed adjacent the recess. A retainer is sized to fit in the recess, with the retainer having an aperture disposed adjacent an end, the end of the retainer sized to block a portion of the second opening of the second bore. 
   In further accordance with one or more preferred embodiments, the second bore houses a wedge assembly, and the recess is sized to permit the wedge assembly to be inserted into the second opening of the second bore through the recess. The wedge assembly includes a plurality of wedges adapted to engage a cross member of the roof truss with progressively greater force in response to movement of the wedge assembly further into the tapered portion. The end of the retainer may be arranged to prevent the plurality of wedges from exiting the second bore into the recess, and the wedge assembly may include a removable spacer plug. The end aperture of the retainer is sized to permit the spacer plug to pass between the aperture and the recess while retaining the plurality of wedges in the second bore. 
   The retainer may include a cylindrical first portion and a semi-cylindrical second portion, and the retainer may be formed from a generally cylindrical tube having a notch. The retainer may be sized to extend at least partially into the second bore, or an end of the retainer may be positioned adjacent the opening to the bore without actually entering the bore. The recess may have a shaped lower surface, and a lower surface of the retainer may be shaped to engage the lower surface of the recess. These surfaces may be semi-cylindrical. 
   In accordance with another aspect of the invention, a truss shoe comprises a base having a pair of ends, pair of sides extending between the ends, with one of the pair of sides including a curved portion, a top side, and a bearing surface adapted to abut a mine roof. An angled stanchion is carried on the top side and has a first bore extending through to the bearing surface. The stanchion and the first bore are adapted to receive an inclined support of the roof truss. The base includes a second bore having a tapered portion, the second bore extending along an axis generally parallel to a plane of the bearing surface, the second bore having a first opening adjacent one of the ends of the housing and a having second opening disposed adjacent a recess. A wedge assembly is disposed in the tapered portion of the second bore, and the recess is sized to permit the wedge assembly to be inserted into the second bore through the second opening, with the wedge assembly including a plurality of wedges adapted to engage a cross member of the roof truss with progressively greater force in response to movement of the wedge assembly further into the tapered portion. A retainer is disposed at least partially in the second bore and positioned to retain the plurality of wedges in the second bore. 
   In accordance with a further aspect of the invention, a method of securing a cross member of a mine roof truss system to a truss shoe comprises the steps of providing a truss shoe having an inclined bore, a generally horizontal bore, a bearing surface, and a curved side edge, placing a wedge assembly in the horizontal bore, providing a retainer adapted to engage the truss shoe to prevent the sedge assembly form exiting the horizontal bore, using the inclined bore to secure the truss shoe to an inclined support member, and using the horizontal bore to secure the truss shoe to a cross member. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a truss shoe for a mine roof assembled in accordance with the teachings of a disclosed example of the present invention; 
       FIG. 2  is an enlarged perspective view of the truss shoe off  FIG. 1  taken from the other side; 
       FIG. 3  is a top plan view thereof; 
       FIG. 4  is a right to side elevation all view taken along line  4 - 4  all of  FIG. 3 ; 
       FIG. 5  is a front side elevational view of the truss shoe; 
       FIG. 6  is a cross-sectional view taken along line  6 - 6  of  FIG. 3 ; 
       FIG. 7  is a perspective view of an assembled world to truss employing a pair of spaced apart truss shoe is assembled in accordance with the teachings of the present invention and joined apart by a central coupler; 
       FIG. 8  is an elevation all view of a roof truss shown in place in a mine roof; 
       FIG. 9  is a cross-sectional view of a truss shoe shown in place in a mine roof truss; 
       FIG. 10A  is an end view of the truss shoe taken along line  10 - 10  of  FIG. 9 ; 
       FIG. 10B  is an end view similar to  FIG. 10A  but illustrating an optional spring clip disposed adjacent the J-shaped bore; 
       FIGS. 11-17  illustrate one manner of installing a truss shoe when forming a roof truss, and illustrating the truss shoe self-rotating between a first position ( FIG. 11 ) and a second position ( FIG. 17 ) in response to tensioning the inclined roof bolt; 
       FIG. 18  is an elevation view, partly in cross section, of a truss system utilizing a truss shoe assembled in accordance with the teachings of the present invention and shown disposed in a mine passage; 
       FIG. 19  is an isometric and partly exploded view of a truss shoe for a mine roof prior to receiving a cross member; 
       FIG. 20  is an isometric view similar to  FIG. 19  and showing a retainer in place in a recess of the truss shoe; 
       FIG. 21  is an enlarged cross-sectional view of the truss shoe shown in  FIGS. 19 and 20  and showing a cable or cross member of the roof truss received by the truss shoe and about to abut a wedge plug; 
       FIG. 22  is cross-sectional view similar to  FIG. 21  and illustrating the cross member having dislodged the wedge plug in the truss shoe; 
       FIG. 23  is cross-sectional view similar to  FIGS. 21 and 22  and illustrating the cross member in tension and gripped by a wedge assembly; 
       FIG. 24  is an enlarged isometric view of an exemplary wedge assembly; 
       FIG. 25  is an enlarged fragmentary isometric view of the truss shoe of  FIG. 19  and illustrating an alternate embodiment for the retainer; 
       FIG. 26  is an enlarged fragmentary isometric view similar to  FIG. 25  but illustrating yet another alternate embodiment for the retainer; and 
       FIG. 27  is an enlarged isometric view of a retainer similar to the retainer shown in  FIG. 19 , but having a tapered or sloping cut instead of a notch. 
   

   While the devices and methods described herein are susceptible to various modifications and alternative constructions, certain illustrative embodiments have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed. On the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the disclosure. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The example described herein is not intended to be exhaustive or to limit the scope of the invention to the precise form or forms disclosed. Rather, the following exemplary embodiment has been chosen and described in order to best explain the principles of the invention and to enable others skilled in the art to follow the teachings thereof. 
   Referring now to  FIGS. 1-3  of the drawings, a truss bracket or truss shoe assembled in accordance with the teachings of the present invention and for use in a mine roof truss is shown and is generally referred to by the reference numeral  10 . The truss shoe  10  includes a top side  12 , a generally planar bottom side  14 , a pair of ends  16 ,  18 , and a pair of sides  20 ,  22 . For purposes of the following discussion, the terms “top” and “bottom” are used to refer to elements of the truss shoe  10  when the truss shoe  10  is disposed as shown in  FIGS. 1-6 . It will be understood that when the truss shoe  10  is used in a mine roof truss as will be explained in greater detail below and as shown in  FIGS. 7-10 , the bottom side  14  will face generally upward and will be in abutting contact with the roof of the mine. In the disclosed example, the end  16  and the side  20  meet along a generally curved transition  23 . The end  16  includes a face or edge  16   a , while the curved transition  23  includes a face or edge  23   a.    
   A stanchion  24  and a retaining bracket  26  are formed on the top side  12  of the truss shoe  10 , with the stanchion  24  including a bore  28 . The bore  28  includes a seat  30  formed adjacent an upper end  32  of the bore  28 , and the bore  28  extends through the bottom side  14  to form a slot  34  (best visible in  FIGS. 6 and 7 ) formed in the bottom side  14  of the shoe  10 . It will be appreciated that the stanchion  24  and hence the bore  28  are disposed at an angle relative to the generally planar bottom side  14 . 
   The retaining bracket  26  is formed by a pair of spaced apart walls  36   a ,  36   b  which extend generally from the stanchion toward an end wall  38 . The end wall  38  includes a J-shaped bore  40 . The J-shaped bore  40  includes an opening or slot  42  formed in the end wall  38 . The bore  40  may also include a retaining lip  44  ( FIG. 4 ). A recessed seat  46  is formed adjacent an inner end  48  of the bore  40 . A space  50  is defined between the stanchion  24  and the end wall  38 , with the space  50  bounded, at least in part, by the walls  36   a  and  36   b.    
   The bore  28  includes an axis generally referred to by the reference arrow A, while the bore  40  includes an axis generally referred to by the reference arrow B. The axis A is disposed at an angle relative to a plane of the bottom side  14  of the shoe  10  and, preferably, will be disposed so as to roughly approximate the angle of an inclined roof bolt disposed in the roof of the mine as will be discussed in greater detail below. The axis B is disposed generally parallel to the plane of the bottom side  14  of the shoe  10 . 
   Referring now to  FIG. 5 , in the disclosed example, the edge  20   a  and the edge  23   a  both preferably include an angle or chamfer,  20   b  and  23   b , respectively. The edge  16   a  may also include a chamfer  16   b  ( FIGS. 5 and 6 ). As shown in  FIG. 6 , the seat  30  of the bore  28  is recessed relative to the upper end  32  of the bore  28 . Preferably, the seat  30  will have a generally conical or a generally spherical shape. Also, the bore  28  widens and expands as the bore  28  proceeds from the upper end  32  toward a lower end  51 , with the bore  28  terminating in the slot  34  ( FIG. 6 ) formed in the bottom side  14  of the shoe  10 . Referring to  FIG. 6 , the J-shaped bore  40  is shown toward the right side of the drawing, with the bore  40  extending from the seat  46  to an end  52 . Preferably, the seat  46  will have a generally conical or a generally spherical shape. 
   Referring now to  FIGS. 3 and 4 , the slot  42  of the J-shaped bore  40  is defined, at least in part, by a pair of edges or faces  54   a ,  54   b  defined in the end wall  38  of the retaining bracket  26 . The faces  54   a  and  54   b  cooperate to define a gap  56 . The gap  56  is sized to receive the shank of a horizontal bolt as will be explained in greater detail below. Further, it will be understood that the gap  56  and the space  50  are sized to permit the horizontal bolt having an attached head to be mounted to the truss shoe  10  as will be explained below. Further, with it will be understood that the space  50  is sized to receive the head attached to the horizontal bolt. 
   Referring now to  FIGS. 7 and 8 , a pair of truss shoes  10  are shown in spaced apart arrangement and disposed generally adjacent a roof  60  of a mine  62  to form a roof truss  11 . Each of the truss shoes  10  is attached to a corresponding inclined roof bolt the  64   a  and  64   b . Each of the roof bolts may be of a conventional roof bolt of the type commonly employed in the art, with each of the roof bolts  64   a ,  64   b  including an anchored portion  66   a ,  66   b , respectively. The anchored portions  66   a ,  66   b  of each bolt  64   a ,  64   b  may be anchored to the surrounding rock (i.e. the roof  62 ) using cement, epoxy resin, a mechanical expansion shell, or any other suitable means of securement. Each of the bolts  64   a ,  64   b  also includes an exposed end  68   a ,  68   b , with each exposed end having a retaining nut  70  ( FIG. 9 ). Preferably, each retaining nut  70  may be generally rounded or otherwise formed to correspond to the shape of the seat  30  ( FIG. 6 ) on each of the truss shoes  10 . Alternatively, the retaining nuts  70  may be provided with a washer sized to correspond to the shape of the seat  30 . 
   Referring to  FIG. 8 , a cross member  72  having a first part  72   a  and a second part  72   b  extends between the spaced apart truss shoes  10 . In the disclosed example, the first and second parts  72   a  and  72   b  are joined together by a central coupler  74 . Each of the first and second parts  72   a  and  72   b  is preferably threaded or otherwise constructed to receive suitable fasteners such that, in the disclosed example, each of the first and second parts  72   a  and  72   b  can be tensioned at the central coupler  70 . In the disclosed example, each part  72   a  and  72   b  includes an inner end  75   a ,  75   b , respectively, that is joined to the central coupler  70  using hex nuts  76  or other suitable fasteners. Each of the first and second parts  72   a  and  72   b  also includes an outer end  78   a  and  78   b , respectively, with the outer ends  78   a  and  78   b  being attached to a corresponding one of the shoes  10  using for example, a pre-fixed terminal end  79  ( FIG. 9  and  FIG. 10A ). Alternatively, the terminal end  79  may be either a nut or a threaded cross member or a fixed end similar to a barrel and wedge on a cable cross member. It will be appreciated when viewing  FIG. 9  that the space  50  between the stanchion  24  and the retaining bracket  26  is large enough to accommodate the appropriate end of the cross member  72  and the exposed ends  68   a  and  68   b  of the inclined roof bolts  64   a  and  64   b  without interference between the cross member and the inclined bolt. 
   Referring now to  FIG. 10A , the truss shoe  10  is shown with the bearing surface of the bottom side  14  facing upwardly and in contact with the roof  60  of the mine  62 . The shank of the horizontal bolt  72  is shown disposed in the J-shaped bore  40 . It will be understood that the horizontal bolt  72  may be placed into the bore  40  by manipulating the shank of the bolt  72  in a generally upward direction through the gap  56  defined by the opposed faces  54   a  and  54   b . The shank of the bolt  72  will be retained as shown due to, at least in part, the presence of the retaining lip  44 . The retention provision of the retaining lip  44  may be enhanced by providing a mounted spring clip  45  as shown in  FIG. 10B  The spring clip  45  opens in order to allow passage of the end of the cross member, and then closes to prohibit the cross member to slip back out of the J-slot  40 . Thus the spring clip  45  serves as a gate. Accordingly, the a bolt  72  will stay positioned as shown regardless of whether the bolt  72  has been tensioned at the coupler  74  using the hex nuts  76 . 
   Referring now to  FIGS. 11-17 , one manner of installing the truss shoe  10  is shown. In a first position, the truss shoe  10  is positioned with the edge  16   a  on the end  16  in abutment with the mine roof  60  or in abutment with the mine roof  60 . The exposed end  68   a  of the inclined roof bolt  64   a  is shown prior to tensioning the bolt  64   a  by tightening the hex nut  70 . As the roof bolt  64   a  is inserted into the bore hole using, for example, right-hand rotation and thrust, the bolt is then tensioned using, by way of example rather than limitation, a conventional bolting machine (not shown). Thus, it will be appreciated that the truss shoe  10  will shift along the curved surface  23 , aided, at least in part, by the chamfered edges  16   b ,  20   b  and/or  23   b . Thus, the truss shoe  10  may shift and/or rotate gradually as the inclined roof bolt  64   a  is tensioned by rotating the nut  70 , which permits the truss shoe  10  to end up as shown in  FIG. 17  tightened against the mine roof, with the bearing surface on the bottom side  14  in abutment with the mine roof. The position of the truss shoe  10  as depicted in  FIG. 17  is such that the installing mine operator does not have to directly manipulate the truss shoe  10  significantly before installing the cross member. It is understood, that the truss shoe  10  depicted with the curved edge  23  is designed for use with right-hand rotation during installation of the inclined bolt. For a left-hand installation the curved edge  23  would have to be mirror flipped on the truss shoe  10 . Further, and with reference to  FIG. 8 , as the horizontal bolt  72  is tensioned, the truss shoe  10  is free to rotate slightly about a generally vertical axis C, such that, upon tensioning the horizontal bolt  72  as discussed above the truss shoe  10  will be brought into a desired position with the end  18  and the retaining bracket  26  disposed inwardly generally facing the central coupler  74 . In all other respects, conventional and well excepted installation steps and procedures may be followed. 
   A mine roof truss assembled in accordance with teachings of the invention may thus comprise of a pair of spaced apart inclined bolts joined to a pair of ends of a tensionable cross member coupled at a central coupler to allow for tensioning. The inclined bolts may be installed with the truss shoe such that the shoe will self-rotate into a position suitable to connect the shoe to the cross member. The cross member may be connected to the truss shoe from a safe operator position by swinging the terminal end of the cross member through the J-shaped slot into a retained position in the truss shoe. The cross member may be retained therein by the lip formed in the J-slot and, optionally, by a spring clip attached to the truss shoe. The retention provision does not require tension in the cross member which significantly facilitates the installation of the truss as well as secures the cross member in the event the tension in the cross member drops during use of the truss. 
   Referring now to  FIG. 18  of the drawings, a pair of truss shoes  110  assembled in accordance with the teachings of a second disclosed example of the present invention are shown, and are spaced apart generally adjacent a roof  160  of a mine  162  to form a roof truss  111 . The construction and assembly of the roof truss  111  may be similar to the construction and assembly of the roof truss  11  discussed above with respect to the first disclosed example. Each of the truss shoes  110  is attached to a corresponding one of a pair of inclined roof bolts  164   a  and  164   b . Again, each of the roof bolts may be a conventional roof bolt of the type commonly employed in the art, with each of the roof bolts  164   a ,  164   b  including an anchored portion  166   a ,  166   b , respectively. The anchored portions  166   a ,  166   b  of each bolt  164   a ,  164   b  may be anchored to the surrounding rock (i.e. the roof  162 ) using cement, epoxy resin, a mechanical expansion shell, or any other suitable means of securement. Each of the bolts  164   a ,  164   b  also includes an exposed end  168   a ,  168   b , with each exposed end having a suitable retaining nut  170 . The cross member  172  again includes the first part  172   a  and the second part  172   b , and extends between the spaced apart truss shoes  110 , with the parts  172   a  and  172   b  again joined together by a central coupler  174 , which may be conventional. Further, except as outlined below, the following embodiment(s) may be substantially similar to the above-described embodiment in all relevant respects. Further, the installation and assembly of the mine roof truss may be the same or similar as that described above with respect to the first disclosed embodiment. 
   Referring now to  FIGS. 19 and 20 , the truss shoe  110  includes a top side  112 , a generally planar bottom side  114 , a pair of ends  116 ,  118 , and a pair of sides  120 ,  122 . Again, for purposes of the following discussion, the terms “top” and “bottom” are used to refer to elements of the truss shoe  110  when the truss shoe  110  is disposed as shown in  FIGS. 19 and 20 , for example. It will be understood that when the truss shoe  110  is used in the mine roof truss  111 , the bottom side  114  will face generally upward and will be in abutting contact with the roof of the mine. In the example of  FIGS. 19 and 20 , the end  116  and the side  120  may meet along a generally curved transition  123 . Accordingly, the end  116  may includes a face or edge  116   a , while the curved transition  123  may includes a face or edge  123   a.    
   The truss shoe  110  includes a stanchion  124  and a housing  126 , both formed on or otherwise attached to the top side  112  of the truss shoe  110 . The stanchion  124  and the housing  126  are separated by a recess  127 . In the example shown, the recess is generally semi-cylindrical in shape, with a surface  129  of the recess  127  generally conforming to the shape of a cylinder cut lengthwise. Other shapes for the recess may prove suitable. The stanchion  124  includes a bore  128 , which extends through to the bottom side  114  along an axis A. Again, the stanchion  124  is preferably disposed at an angle relative to the generally planar bottom side  114 . Therefore, the bore  128  also is disposed at an angle relative to the bottom side  114 . The stanchion  124  and the bore  128  may be similar in all respects to the stanchion and bore described above with respect to the first disclosed embodiment, and are adapted to secure one of the inclined bolts  166   a  or  166   b  to the truss shoe  110  in a manner similar to that described above with respect to the first disclosed example. 
   The housing  126  includes a pair of ends  136   a ,  136   b , and a bore  140  having an axis C extends between the ends  136   a  and  136   b , such that the bore  140  extends through the housing  126 . As can best be seen in  FIGS. 21 ,  22  and  23 , the bore  140  preferably includes a tapered portion  141 , and is sized to receive one of the parts  172   a  (not shown in  FIGS. 21-23 ) or  172   b  (shown in  FIGS. 21-23 ) of the horizontal cross member  172 , as well as a wedge assembly  146 . The wedge assembly  146  may be placed in the bore  140 , such that the wedge assembly  146  will engage a portion of a corresponding one of the parts  172   a  or  172   b  of the horizontal cross member  172 . The bore  140  may also include a widened portion  143  toward the end  136   b  of the housing  126 , which is adjacent the end  118  of the truss shoe  110 . 
   As shown in  FIG. 19 , a retainer  190  includes a cylindrical portion  191  and a semi-cylindrical portion  192 . The retainer  190  may be formed from a hollow cylinder having a through bore  193  and an outer surface  194 . A notch  195  cut into the cylinder forms the cylindrical portion  191  and the semi-cylindrical portion  192 . The bore  193  extends through an end  196  of the retainer  190 , with the end  196  including a face  197 . 
   Alternatively, as illustrated in  FIG. 27 , a retainer  190 A may be used. As shown in  FIG. 27 , the retainer  190 A also includes the cylindrical portion  191  and the semi-cylindrical portion  192 , and again is formed from a hollow cylinder having the through bore  193  and the outer surface  194 . However, instead of a notch, the retainer  190 A has a sloping or tapered cut  195 A. Once again, the bore  193  extends through the end  196  of the retainer  190 A, with the end  196  including the face  197 . The retainer  190 A may be used in the same or similar manner as the retainer  190 , and may be substituted for all the descriptions and/or use of the retainer  190 . 
   Referring now to  FIGS. 21-23 , the recess  127  and a bore  140  are shown in cross-section. The wedge assembly  146  is shown disposed in the tapered portion of the bore  140 , and a plug  185  (discussed in greater detail below with respect to  FIG. 24 ) is disposed inside the wedge assembly  146 . The retainer  190  is disposed in the recess  127 , with the end  196  of the retainer  190  extending adjacent to or partially into the bore  140 . With the retainer  127  in the wedge assembly  146  positioned as shown, the face  197  of the retainer  190  prevents the individual wedge pieces  168   a ,  168   b , and  168   c  (discussed in greater detail below with respect to  FIG. 24 ) from exiting the bore  140  into the recess  127 . 
   Referring now to  FIG. 22 , one part  172   b  of the crossmember  172  is shown being inserted into the bore  140  from the left when viewing the Figure. The end of the part  172   b  is sized to fit into a passageway  180  defined by the wedge assembly  146  and, when pushed to the right as shown in  FIG. 22 , the end of the part  172   b  pushes the plug  185  out from between the individual wedge pieces of the wedge assembly  146 . The retainer  190  is sized such that the plug  185  may be dislodged from the truss shoe  110 , and may be removed through or fall out of the open semi-cylindrical portion  192 . The retainer  190  is also sized such that, although the plug  185  may pass through the retainer  190 , the individual wedge pieces are prevented from exiting the bore  140  because the individual wedge pieces will be blocked by the face  197  of the retainer  190 . In other words, the face  197 , which is generally circular and surrounds the opening formed by the bore  193 , partially obstructs a radially outward portion of the bore  193 , thereby preventing the individual wedge pieces and/or the entire wedge assembly  146  from exiting the bore  193  into the recess  127 . Consequently, as shown in  FIG. 23 , when tension is applied to the cable or part  172   b  toward the left when viewing  FIG. 23 , the individual wedge pieces of the wedge assembly  146  apply progressively greater force to the cable or part  172   b  as the wedge assembly  146  moves progressively deeper into the tapered portion  140  of the bore  140 . 
   As shown in  FIG. 24 , the wedge assembly  146  includes a number of individual wedge pieces. In the disclosed example, the wedge assembly  146  includes first, second, and third wedge pieces  168   a ,  168   b , and  168   c . Together, the pieces combine to substantially form a truncated cone with a base  172  and a tip  174 . Two-piece wedge assemblies or other suitable wedge assemblies may also be employed. 
   Each of the wedge pieces  168   a ,  168   b  and  168   c  has an engaging face  176   a ,  176   b , and  176   c , such that when the wedge pieces  168   a ,  168   b  and  168   c  are assembled to form the wedge assembly  146 , the engaging faces  176   a ,  176   b , and  176   c  are in confronting relationship. Each of the wedge pieces  168   a ,  168   b  and  168   c  also include an internal cylindrical section  178   a ,  178   b , and  178   c . When the wedge pieces  168   a ,  168   b  and  168   c  are assembled to form the wedge assembly  146 , the faces  176   a ,  176   b  and  176   c  form a generally circular passageway  180  within the wedge assembly  146 . A set of teeth  182  are disposed on the faces  178   a ,  178   b , and  178   c . The teeth  182  may be formed in a known way such that an object in the passageway  180  may slide from the tip  174  of the wedge assembly  146  towards the base  172 , but locked or resisted with respect to sliding from the base  172  toward the tip  174 . A groove or recess  184  is disposed on the outside surface of each of the wedge pieces  168   a ,  168   b  and  168   c , generally adjacent to the base  172 . The groove  184  encircles the wedge assembly  146  at a generally constant distant from the base  172 . A cylindrical plug  185 , which may be a short dowel pin, is sized to be placed in the passageway  180 . A resilient ring  187  is sized to be seated in the groove  184  of the wedge assembly  146 . The ring  187  is preferably a resilient O-ring formed from, for example, rubber or other suitable material. The ring  187  can also be made from plastic or a suitable metal, and is preferably flexible to facilitate easy installation of the ring  187  into the groove  184  around the wedge assembly  146 . 
   In the disclosed example, the plug  185  and the ring  187  cooperate to maintain the wedge pieces together as shown, for example, in  FIG. 19 . Additional details of the wedge assembly  146  and the individual wedge pieces can be found in co-pending U.S. patent application Ser. No. 11/224,492, filed Sep. 12, 2005, and entitled Cable Coupler Having Retained Wedges, the entire disclosure of which is incorporated by reference herein. 
   Referring now to  FIG. 25 , another exemplary embodiment for the retainer is shown. Except for the items mentioned herein, for ease of reference the items mentioned above with respect to  FIGS. 18-24  will retain their same reference numerals. In the example of  FIG. 25 , a retainer  290  takes the form of a U-shaped pin having a pair of prongs  291  and a crossmember  292 . The housing  126  includes a pair of apertures  293  that extend into the bore  140 . The spacing between the pins  291  is sufficient to permit the plug  185  to pass into the recess  127 . However, as with the retainer  190  discussed above, the retainer  290  prevents the individual wedge pieces of the wedge assembly  146  from exiting the bore  140  into the recess  127 . The remaining details of the truss shoe may be the same or similar to those details discussed above with respect to  FIGS. 18-24 . 
   Referring now to  FIG. 26 , yet another exemplary embodiment for the retainer is shown. Once again, except for the items mentioned herein, for ease of reference the items mentioned above with respect to  FIGS. 18-24  will retain their same reference numerals. In the example of  FIG. 26 , a retainer  390  takes the form of a disc  391  having an annular flange  392 . The retainer  390  of  FIG. 26  may generally resemble a bottle-top shape, and may include a central aperture  393  surrounded by an outer portion  394 . As shown, the retainer  390  is disposed in the bore  140  of the truss shoe, such that the outer portion  394  blocks a portion of the bore  140 . The central aperture  393  is preferably sized to permit the plug  185  of the wedge assembly  146  (both of which are discussed above in greater detail and are shown at least in  FIG. 24 ) to pass through the aperture  393 . When oriented as shown, the flange  392  extends outwardly away from the bore and toward the recess  127 . Alternatively, the retainer  390  may be oriented so that the flange  392  extends inwardly into the bore  140 . The retainer  390  may be constructed from a rigid material or from a deformable material, such as metal, certain plastics, etc. Other materials may prove suitable. As with the retainers  190  and  290  discussed above with respect to the previously-discussed examples, the retainer  390  is positioned to retain the individual wedge pieces of the wedge assembly  146  in the bore  140 , while permitting the plug  185  to be dislodged in a manner similar to that shown in  FIG. 22 . The retainer  390  preferably is maintained in the bore  140  by an interference fit between the flange  392  and the inner surface of the bore  140 . 
   Numerous additional modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing description. This description is to be construed as illustrative only, and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and method may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications which come within the scope of the appended claims is reserved.