Abstract:
The present invention is directed to a device and assembly for the anchoring and tensioning of cable bolts used in earthen formations to stabilize the earthen structures to prevent or minimize the caving in or sluffing-off of the earthen structure. The new invention presents an integral wedge barrel and threaded sleeve which can be turned to facilitate both the mixture of cementing resins and the physical tensioning of an anchored cable and which can reduce or prevent undesirable twisting of the cable during tensioning.

Description:
RELATED INVENTIONS 
       [0001]    This application is a Continuation-in-Part of my co-pending application Ser. No. 12/022,051 filed on Jan. 29, 2008, for Resin Mixing and Cable Tensioning Device and Assembly For Cable Bolts. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a device and assembly for cable bolt systems. In particular, the present invention relates to cable bolt apparatus which can be used to both mix associated cable resin and to tension the cable bolt assembly against a bearing plate. 
         [0004]    2. Background and Related Art 
         [0005]    Steel bolts and cable bolts are commonly used in underground mines to stabilize geologic layers adjacent mine openings. For example, cable bolt assemblies are used to secure the geologic layers of the roof of a mine tunnel or drift to prevent roof strata from falling and causing obstructions or injury to persons or equipment in the tunnel. 
         [0006]    Rigid members such as steel rods or rebar have long been used in anchoring systems in construction applications and as rock bolts in mining applications. For example, threaded rebar manufactured and sold by DYWIDAG under the brand name Threadbar has been used for rock bolts for years. Anchoring such rods or rebar at one end or at both ends allows the rod to bear a tension load. Steel rods have been particularly useful in anchoring applications because threads can be formed on the outer surface of the rods to receive desired bolts with corresponding threads or to receive other fastening devices such as a Frazer-Jones D9 expansion shell assembly. Rigid steel rods are, however, not always ideal because they are manufactured in finite, fixed lengths and long rods are often difficult to work with in confined spaces such as construction and mining sites. Rigid rods can also be subject to shearing stresses if, for example, there is ground movement adjacent the rod in a mining application. 
         [0007]    Steel cables comprising multiple strands of steel have also been used as anchoring systems. Unlike rigid, steel rods, cables provide some flexibility along their length. That is, a cable can bent around an object or deflect when subject to ground movement adjacent the cable. In some instances, steel cable is easier to use in confined spaces. Historically, anchoring a cable at one or both ends is more difficult because the cable does not bear threads to receive bolts. A number of cable anchoring methods have been used. One example is a multistrand anchorage device which separates strands of the cable and anchors each strand individually or in groups such as the DYWIDAG Multistrand Posttensioning System. Another example comprises positioning a thread-bearing sleeve along the length of the cable at the desired locations to receive a desired bolt or Frazer-Jones D9 expansion shell assembly. 
         [0008]    Another example includes unraveling the cable and sliding a ring over and down along the center or king wire of the cable to a desired location and then rewinding the cable. In this way, a bulge or ‘bird cage’ is formed in the cable due to a spreading of the wires in the area of the ring. The bulge or spreading of the wires permits resin used with the cable to permeate into the cable to enhance anchorage of the cable upon the setting of the resin. If mechanical anchorage is also desired, an additional thread-bearing or thread-like-bearing apparatus must still be added if a desired bolt or Frazer-Jones D9 expansion shell assembly is to be used. 
         [0009]    A number of devices rely upon a thread-bearing sleeve being disposed about the cable or other threaded systems to tension a cable. The sleeve is positioned relative to the cable or other threaded systems which are used to tension the cable including: 
         [0010]    (1) placing a threaded tube and clamping it on the cable; 
         [0011]    (2) threading the cable itself; 
         [0012]    (3) placing and securing the cable inside a threaded bar such as a DYWIDAG threadbar® with a hole in it; and 
         [0013]    (4) using a threaded insert which is placed over the king wire and then threaded inside a Frazer-Jones D9 expansion shell assembly. 
         [0014]    A number of cable and other bolt assemblies are known, including those taught by U.S. Pat. Nos. 2,667,037, 3,077,809, 4,509,889, 4,954,017, 4,984,937, 5,015,125, 5,026,517, 5,215,411, 5,230,589, 5,259,703, 5,375,946, 5,378,087, 5,441,372, 5,458,442, 5,525,013 and others. 
         [0015]    These techniques include drilling a long hole into the earthen geology which is to be stabilized. A requisite amount of multi-component epoxy resin is placed in the hole at the desired location. The steel cable is also placed in the hole. A machine is used to spin the cable thereby mixing the multi-component epoxy to cause the chemical reaction between the multi-components. The epoxy sets and anchors the cable in the hole. 
         [0016]    Known techniques for mixing multi-component epoxy include mechanical devices designed to spin the cable at a relatively low torque to mix the epoxy components followed by tensioning the cable using increased torque after the cable is cemented in place. The mechanical devices include known and available domed nuts, crimped bolts, perpendicular roll pins, shear pins, weld beads, and keys ways which permit spinning a nut or other structure on a threaded sleeve at a low torque without compromising or defeating the ability of the domed nuts, crimped bolts, perpendicular roll pins, shear pins, weld beads, and keys ways to at least temporarily fix the relative position of the nut and threaded sleeve affixed to the cable. In this way, the spinning of the cable mixes the epoxy resin components. After the cable is cemented in place, a higher torque is then applied, typically in the same direction as the low torque, to tension the cable which use of higher torque does compromise or defeat the ability of the domed nuts, crimped bolts, perpendicular roll pins, shear pins, weld beads, and keys ways to fix the relative position of the nut and threaded sleeve. 
         [0017]    When tensioning a steel cable, it is not uncommon for the cable itself to twist somewhat between the point of application of torque for tensioning and the point at which the cable is cemented in place. This can cause a slight decrease in the length of the cable. Upon release of the torquing device the cable can untwist thereby returning to its longer repose length and causing an undesirable decrease in the tension on the cable. 
         [0018]    Accordingly, it would be an improvement in the art to augment or even replace current techniques with simpler devices and devices which permit the use of power tools which apply torque in opposing directions and avoid unwanted decrease in tensioning of the cable after removal of the torquing tool. 
       SUMMARY OF THE INVENTION 
       [0019]    The present invention relates to an integral wedge barrel and threaded sleeve which can be used for both spinning to mix epoxy resin and used to tension a cable bolt. 
         [0020]    The present invention contemplates a unitary or integral wedge barrel and threaded sleeve with a rotatable nut about the threaded sleeve. The threaded sleeve is disposed in an aperture of a bearing plate. A cable is disposed through the threaded sleeve and through the wedge barrel. The cable is fixed in place relative to the wedge barrel by common barrel wedges. When assembled the cable is fixed relative to the wedge barrel. The threaded sleeve is fixed relative to the barrel because the threaded sleeve and wedge barrel are either manufactured as one integral unit or are joined together in a fixed relationship by means of welding or some other common joining practice. 
         [0021]    In use, the device permits reliable mixing of epoxy resin components by rotating the nut until it abuts the wedge barrel whereupon the cable will spin in the direction the nut is being turned. This turning or spinning action can be used to mix the epoxy resins. 
         [0022]    In some applications, after the epoxy resin is set and the cable cemented in place, the nut may be turned or spun in the opposite direction causing the nut to move away from the wedge barrel and move toward the opposing bearing plate against which the nut can be forced by applying high torque to the nut whereby the cable is put under tension. In other applications it may be necessary to use known techniques thereby turning the cable in the same direction for both mixing and tensioning. 
         [0023]    The bearing plate may comprise one or more projections or protrusions from the face or edge of the bearing place toward the surface against which the bearing place is disposed. This provides points of contacts between the bearing plate and for example an earthen or rock surface to reduce or prevent the bearing place resting against a surface from spinning when the cable is being tensioned. 
         [0024]    The structure of the aperture of the bearing plate and the threaded sleeve disposed in the aperture permit the threaded sleeve to slide through the bearing plate to permit tensioning while at the same time reducing or preventing any twisting of the cable-bearing threaded sleeve within the aperture. 
         [0025]    While the methods and processes of the present invention have proven to be particularly useful in the area of cable bolt tensioning, those skilled in the art can appreciate that the methods and processes can be used in a variety of different applications and in a variety of different areas of manufacture to yield an equivalent device. 
         [0026]    These and other features and advantages of the present invention will be set forth or will become more fully apparent in the description that follows and in the appended claims. The features and advantages may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. Furthermore, the features and advantages of the invention may be learned by the practice of the invention or will be obvious from the description, as set forth hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    In order that the manner in which the above recited and other features and advantages of the present invention are obtained, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. Understanding that the drawings depict only typical embodiments of the present invention and are not, therefore, to be considered as limiting the scope of the invention, the present invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
           [0028]      FIG. 1  illustrates a perspective view of one embodiment of the device and system that provides a suitable structure and function for the present invention; 
           [0029]      FIG. 2  illustrates a cross-sectional view of an embodiment of the present invention; 
           [0030]      FIG. 3  illustrates a cross-sectional view of an embodiment of the present invention; 
           [0031]      FIG. 4  illustrates use of the present invention with a breakaway view of a cable cemented into a geological formation. 
           [0032]      FIG. 5  illustrates a perspective view of another embodiment of the bearing plate; 
           [0033]      FIG. 6  illustrates a perspective view of another embodiment of the a threaded sleeve with at least one flatten side; 
           [0034]      FIG. 7  illustrates a cross-sectional view of another embodiment; 
           [0035]      FIG. 8  illustrates a cross-sectional view of another embodiment; 
           [0036]      FIG. 9A  illustrates a partial cross-sectional view along line A of  FIG. 8  depicting the relationship between a bearing plate and a threaded sleeve; 
           [0037]      FIGS. 9B ,  9 C and  9 D illustrate partial cross-sectional views of alternative embodiments of  FIG. 9A ; 
           [0038]      FIG. 10  illustrates use of another embodiment of the present invention with a breakaway view of a cable cemented into a geological formation. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]    The present invention relates to a device for use in anchoring and tensioning cables or cable bolts to stabilize walls or ceilings in earthen bodies such a mines or other underground openings. In particular, the present invention is directed to a integral device which both facilitates mixing the epoxy resins used to anchor the cable bolt in the earthen body and tensioning the cable bolt after it is anchored in place. The present invention contemplates an integral wedge barrel used to capture a cable bolt and a threaded sleeve about the cable bolt. 
         [0040]      FIG. 1  and the corresponding discussion are intended to provide a general description of one embodiment of the present invention. One skilled in the art will appreciate that the invention may be practiced by one or more embodiments in a variety of configurations. Mixing and tensioning assembly  10  is shown in perspective view. Assembly  10  comprises cable or cable bolt  20 , an integral body  30  of a wedge barrel and threaded sleeve disposed about cable bolt  20 , nut  40  disposed along integral body  30  and bearing plate  50 . Cable bolt  20 , nut  40  and bearing plate  50  are all commonly known, used and available cable bolt components. 
         [0041]    As depicted in  FIG. 2 , device or integral body  30  comprises a wedge barrel end  32  defining sloped interior surface  34  to receive a plurality of wedges  36 . Integral body  30  further comprises a threaded sleeve portion  38 . While the preferred embodiment contemplates integral body  30  being a continual unitary member, a person of skill in the art would recognize that other embodiments would contemplate an interface between a wedge barrel and a threaded sleeve achieved via a weld between a wedge barrel and a threaded sleeve, via a recessed barrel with a mating surface corresponding to a mating end of a threaded sleeve, via screwing the threaded sleeve into the wedge barrel, or via prongs on one end of the threaded sleeve engaging apertures in the wedge barrel, all to fix the interrelationship between the wedge barrel and the threaded sleeve. The result in all embodiments being a interdependent wedge barrel and threaded sleeve which when either part is acted upon by a force the same or substantially similar force is also transmitted to the other part of the integral body  30 . 
         [0042]    Cable bolt  20  is disposed within integral body  30 . As is commonly known in the art, wedges  36  disposed between cable bolt  20  and wedge barrel  32  act by friction and/or other forces to fix cable bolt  20  within integral body  30  such that force along bolt  20  is transmitted to integral member  30  and vice versa. 
         [0043]    Nut  40  is disposed along a length of body  30  between wedge barrel portion  32  and bearing plate  50 . Nut  40  can be turned in both directions. As shown in  FIG. 2 , when nut  40  is turned until it abuts wedge barrel  32 , then upon abutting wedge barrel portion  32 , further turning of nut  40  will cause both body  30  and bolt  20  to turn or spin in the same direction. This spinning can be used to spin cable bolt  20  to mix epoxy resins as discussed below. 
         [0044]    As shown in  FIG. 3 , nut  40  can also be turned in the opposite direction until it abuts bearing plate  50 , or one or more optional washers  60  constructed of metal and/or HDEP, Teflon, nylon, or similar materials to reduce friction. As known in the art, plate  50  may be dome-shaped. Bearing plate  50  defines a plate aperture  52  to permit plate  50  to move independent of body  30 . Similarly, optional washer  60  defines a washer aperture  62  to permit washer  60  to move independent of body  30 . Upon abutting plate  50  or washer  60 , continued turning or spinning of nut  40  in the same direction puts a force upon plate  50  thereby putting cable bolt  20  in tension as plate  50  is forced against a geologic formation such as rock, dirt or mineral. It will be appreciated that threaded sleeve portion  38  is of a sufficient length to permit tensioning and, as needed, retensioning of cable bolt  20 . Threaded sleeve portion  38  may be about twelve inches or longer or shorter depending on the geologic conditions of use. 
         [0045]    The present invention permits universal use of assembly  10 . For example, when sleeve threads are right-handed threads as is typical in coal mines, tools are used that are able to turn nut  40  in either direction as depicted in  FIGS. 2 and 3 . 
         [0046]    When sleeve threads are left-handed threads as is typical in hard rock mines, jack-legs are typical tools used to turn nuts  40  but are able to turn nut  40  in only one direction to force nuts  40  against bearing plates  50 . When tools such as unidirection jack-legs are used, the present invention further comprises means for providing a temporary, fixed interface between nut  40  and threaded sleeve portion  38 . The temporary, fixed interface between nut  40  and threaded sleeve portion  38  can be accomplished by known techniques previously discussed including but not limited to known frictional interfaces, weld beads, roll pins, keyway with keys, buggered threads, domed nuts, or crimped sleeves. As a result, turning of nut  40  also turns sleeve portion  38  which turns cable  20 . This commonly known unidirection turning of nut  40  can be used to both mix epoxy resins at a lower torque and then at higher torque to overcome, break or shear the temporary, fixed interface to place bolt  20  under tension. 
         [0047]    An optional sleeve cover, not shown, extends along the length of threaded portion  39  from nut  40  through plate aperture  52  towards the end of portion  38  to protect the threads of portion  38  from being damaged or compromised prior to use. The sleeve cover is disposed about threaded portion  38  and can comprise plastic, soft metal, rubber, cardboard or any other suitable material capable of protecting the threads of sleeve portion  38  from damage prior to use. 
         [0048]    Embodiments of the present invention may comprise other structural features. Bearing plate  50  may comprise one or more projections or protrusion toward the bearing surface. For example,  FIGS. 5 and 7  depict projections  54  which may imbed into or catch onto the bearing surface or onto or into appliances such as metal mesh upon a bearing surface. In place, projections  54  reduce or prevent bearing plate  50  from spinning when torque is applied to tension the cable. As depicted in  FIG. 8 , alternative projections or protrusions  56  may be employed. Projections  56  could be prepared by casting, machining or by adding material to plate  50  such as by welding.  FIG. 8  also depicts other alternative projections  57  which may be formed by a punching or stamping process during manufacture of plate  50 . In all cases, projections  54 ,  56  or  57  act to engage the surface or surfaces against which bearing plate  50  is positioned to reduce or prevent movement or spinning of plate  50 . 
         [0049]    Threaded member  38  may comprise one or more exterior shapes with a corresponding, opposing and mating shape in the aperture  52  of bearing plate  50 , all designed to permit threaded member  38  to slide through aperture  52  of plate  50  but also reduce or prevent threaded member  38  from spinning within aperture  52 . For example,  FIG. 6  depicts threaded member  38  with flattened side  39 .  FIG. 9A  depicts a corresponding, opposing flattened aperture wall  58  of plate  50  which mates with surface  39 .  FIG. 9B  depicts another illustrative embodiment comprising threaded member  38  with two flattened side walls  39  within two corresponding, opposing flattened aperture walls  58  which mate with surfaces  39 .  FIG. 9C  depicts another illustrative embodiment comprising threaded member  38  with keyway  39  with a corresponding, opposing key projection  58  of plate  50  projecting into keyway  39  which mates with surface  39 .  FIG. 9D  depict another illustrative embodiment comprising an alternative threaded member  38  with keyway  39  with a corresponding, opposing key projection  58  of plate  50  projecting into keyway  39  which mates with surface  39 . These embodiments are merely illustrative of one or more opposing surfaces  39  and  58  which permit member  38  to pass through plate  50  but reduce or prevent member  38  from turning or spinning independent of member  38 &#39;s relationship to or position in plate  50 . One skilled in the art may recognize other such structures. The structure and function of embodiments illustrated in  FIGS. 9A-D  are examples of means for substantially preventing the rotation of threaded member  38  and cable  20  when disposed through plate  50 . 
         [0050]    The structure and function of embodiments illustrated in  FIGS. 9A-D  combined with projections  54 ,  56 , or  57  are examples of means for substantially preventing the twisting of cable  20  during tensioning. That is, the means for substantially preventing the twisting of cable  20  during tensioning reduces or prevents the undesirable twisting, shortening and/or lengthening of cable  20  during or after tensioning. The present invention reduces or prevents back-spin of the cable after release from the torquing tool. These devices and techniques may also be used in certain mining operations that use cement grouting systems which require no mixing but utilize similar tensioning of a cable. 
         [0051]    As depicted in  FIGS. 4 and 10 , the subject wall, roof, or floor of a geologic structure  70  is drilled to create drill hole  72 . Epoxy resin components are placed in hole  72  at the desired location. Assembly  10 , preassembled and comprising cable  20 , body  30 , nut  40  and bearing plate  50  is placed such that cable  20  is inserted into hole  72  to a depth so a portion of cable  20  is inserted through or adjacent the epoxy resin components in hole  72 . Nut  40  is turned in the desired direction causing cable  20  to spin in hole  72  to mix the epoxy components to create a epoxy resin or cement  80  which acts to anchor cable  20  in hole  72 . Cable  20  is thrust into hole  72  to the desired depth with the entire device  10  thrust against wall  70  and held in place until the resin sets. After the resin or cement is set and cable  20  is anchored in hole  72 , nut  40  is again turned in the desired direction to further force nut  40  against bearing plate  50 , or washer  60 . This pushes plate  50  against wall  70  putting cable  20  under tension. The appropriate tension is placed upon cable  20  to help stabilize wall  70 . After tensioning, the preferred installation contemplates removing the thrust force by withdrawing the tensioning tool about one quarter inch away from the washer  60  or plate  50  to ensure that the tool is not experiencing friction loss against the washer  60  or plate  50  and nut  40  is again turned for further tensioning. A plurality of assemblies  10  are used over an area to prevent geologic structures  70  from caving in and causing injury to persons or equipment. 
         [0052]    The devices depicted in  FIGS. 5-10  provided the added advantage of having bearing plate  50  affirmatively engage wall  70  or any appliance thereon via projections  54 ,  56 , or  57  to reduce or prevent movement of plate  50  vis-à-vis wall  70 . When torque is applied to tension cable  20 , member  38  may move laterally through plate  50  in the direction of the cable as needed for tensioning. However, because of surfaces  39  and  58  member  38  is not permitted to spin or rotate within aperture  52  of plate  50 . As a result, cable  20  is held in a relatively fixed orientation to wall  70  thereby reducing or preventing twisting of cable  20  between the point of application of torque for tensioning and the point of cementation or anchorage in wall  70  during or after tensioning. 
         [0053]    While the Figures only depict a single cable comprising a plurality of wound or twisted wires, the present invention also contemplates assembly  10  being capable of receiving and securing a number of cables  20  as illustrated in U.S. Pat. No. 5,525,013. 
         [0054]    Thus, as discussed herein, the embodiments of the present invention embrace an assembly  10  comprising a device which can be turned to facilitate both mixing resin or cement to anchor cable  20  and to put cable  20  under the desired tension to secure the adjacent surface. 
         [0055]    The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.