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[0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/524,516, the disclosure of which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure relates to the mining arts and, more particularly, to a drill guide for a drilling apparatus, such as for use in connection with a drill for forming a borehole in a face of a mine passage. 
       BACKGROUND OF THE INVENTION 
       [0003]    Drill guides may be provided for use in connection with guiding a drilling element in the course of forming a borehole in a face of a mine passage. Typically, the drill guide includes a pair of pivotally mounted clamping jaws that close to support the drilling element as the result of the application of hydraulic force. One approach may be found in U.S. Pat. No. 7,428,935 to Hinshaw et al. the disclosure of which is incorporated herein by reference. 
         [0004]    The need to provide a manual holding force for the drilling element while these jaws are closed using hydraulic power can require considerable skill, and often leads to suboptimal results. Also, the drill guide hoses for supplying the working fluid to an associated actuator are usually poorly positioned, and prone to failure as a result. Accordingly, a need is identified for an improved drill guide that meets and overcomes one or more of the foregoing limitations and others. 
       SUMMARY 
       [0005]    One aspect of the invention relates to an apparatus for use in connection using a drill having a drilling element for forming a borehole in a face of a mine passage. The apparatus comprises a drill guide for engaging the drilling element while permitting the drilling element to move toward the face for forming the borehole, the drill guide including a keeper for holding the drilling element. The keeper is biased for pivoting movement upon the application of a manual force between an active position for capturing the drilling element and a retracted position for releasing the drilling element. 
         [0006]    In one embodiment, the keeper includes a first notch aligning with a second notch of an associated support in the active position of the drill guide. The first and second notches together form a passage in the drill guide for receiving the drilling element. 
         [0007]    The apparatus may further include a retainer for retaining the keeper in the active position. The retainer may comprise a hydraulic cylinder having a rod pivotally connected to the keeper. The retainer may also or alternatively comprise a biasing element for urging the keeper toward either the retracted position or active position. 
         [0008]    The apparatus may further including a controller for actuating the retainer when a predetermined condition is met. The predetermined condition may be, for example, receiving a feed signal for feeding the drill from an operator input device, receiving a rotation signal for causing the drill to rotate the drilling element from an operator input device, or both. The controller may also deactivate the retainer to allow for manual movement of the drill guide to the retracted position when both the feed signal and the rotation signal are removed. 
         [0009]    The apparatus may also include a first stop for engaging the keeper in the active position of the drill guide and a second stop for engaging the keeper in the retracted position of the drill guide. 
         [0010]    Another aspect of this disclosure relates to an apparatus for use in connection using a drill having a drilling element for forming a borehole in a face of a mine passage. The apparatus comprises a drill guide for engaging the drilling element while permitting the drilling element to move toward the face for forming the borehole. The drill guide is adapted for pivoting movement between a retracted position for releasing the drilling element from the drill guide and an active position for associating the drilling element with the drill guide. A retainer is provided for retaining the drill guide in at least the active position. A controller is also provided for actuating the retainer on receiving at least one signal corresponding to the movement of the drill relative to the drill guide. 
         [0011]    The controller may actuate the retainer on detecting the presence of one of a feed signal or a rotation signal, or both. The controller may deactivate the retainer to allow for manual movement of the drill guide to the retracted position when both the feed signal and the rotation signal are removed. 
         [0012]    A further aspect of this disclosure pertains to a drill guide having a first jaw for engaging a drilling element in a first plane and a second jaw for engaging the drilling element in a second, adjacent plane. The first jaw may be mounted for pivoting movement relative to the stationary second jaw. 
         [0013]    Still another aspect of this disclosure relates to a drill guide having a support, the support including a notch forming a first jaw for receiving the drilling element and supporting a second jaw pivotally mounted to the support and having a second notch for receiving the drilling element. 
         [0014]    Yet a further aspect of the disclosure pertains to an apparatus for use in connection using a drill having a drilling element for forming a borehole in a face of a mine passage in connection with a mast. The apparatus comprises a drill guide for engaging the drilling element while permitting the drilling element to move toward the face for forming the borehole, the drill guide including at least one movable jaw. The apparatus further comprises an elongated shaft extending along the mast and connected at one end to the at least one movable jaw. An actuator is adapted for rotating the elongated shaft for moving the at least one jaw of the drill guide. 
         [0015]    In one embodiment, the actuator comprises a cylinder including an extendable rod connected to the elongated shaft. The apparatus may further include a delivery line for delivering a working fluid to or from the cylinder. The delivery line may extend extending along the mast. 
         [0016]    Still another aspect of this disclosure pertains to an apparatus for use in connection using a drill having a drilling element for forming a borehole in a face of a mine passage. The apparatus comprises a drill guide having one or more movable jaws for engaging the drilling element while permitting the drilling element to move toward the face for forming the borehole. The drill guide includes a guard having a guide for guiding the drilling element to a position for being engaged by the one or more jaws. 
         [0017]    In one embodiment, the guard comprises a pair of spaced plates, and the guide is non-linear. The guide may include an open end and a closed end. The closed end may align with the opening in the drill guide for receiving the drilling element. 
         [0018]    Another aspect of this disclosure relates to a method for guiding a drilling element for forming a borehole in a face of a mine passage. The method comprises providing a manually operable drill guide for engaging the drilling element while permitting the drilling element to move toward the face for forming the borehole, the drill guide adapted for pivoting movement to move between a retracted position for releasing the drilling element from the drill guide and an active position for associating the drilling element with the drill guide. The method further comprises preventing the drill guide from moving to the retracted position during the drilling of the borehole. 
         [0019]    The method may further include the step of providing a biasing element for biasing the drill guide in at least the active position. Still further, the method may include the step of biasing the drill guide in at least the retracted position, and further including the step of manually moving the drill guide by overcoming the biasing. 
         [0020]    A further aspect of this disclosure relates to a method of delivering a drilling element to a drill guide associated with a drill including a chuck for receiving the drilling element upon being inserted therein. The method comprises delivering the drilling element though a guard for guarding the drill guide before inserting the drilling element in the chuck. The delivering step may comprise passing a portion of the drilling element through a labyrinth guide. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0021]      FIGS. 1-4  schematically illustrate a drill mast in various positions for use in forming boreholes in one or more faces of a mine passage; 
           [0022]      FIG. 5  schematically illustrates a drill guide in a non-actuated condition; 
           [0023]      FIG. 6  schematically illustrates the drill guide of  FIG. 5  in an actuated condition; 
           [0024]      FIG. 7  is a perspective view of a drill mast including a second embodiment of a drill guide; 
           [0025]      FIG. 8  is a perspective view of the drill guide of  FIG. 7  in an actuated condition; 
           [0026]      FIG. 9  is a perspective view of the drill guide of  FIG. 8  in a non-actuated condition; 
           [0027]      FIG. 10  is a perspective view of a third embodiment of a drill guide including a guard; and 
           [0028]      FIG. 11  is a top view of the drill guide of  FIG. 10 . 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    Referring now to  FIGS. 1-4 , this disclosure relates primarily to a drill guide  10  for use in a drilling or bolting machine, or “bolter.” This bolter is used in connection with the installation of support in a face of a mine passage. Specifically, such a bolter is adapted for forming a borehole in the face, and then subsequently installing an anchor (typically an elongated piece of rebar called a “roof bolt”) in the borehole. The drill guide  10  typically lends support to and provides guidance for a drilling element, or “drill steel,” prior to and during the process of forming the borehole, but must also allow for release when the operation is complete. Although reference will be primarily made herein to a drilling element, it should be appreciated that a drill guide may also lend support for the anchor prior to installation in the borehole. 
         [0030]    As shown in  FIG. 1 , the bolter typically includes a mechanism for advancing and retracting a drill D (which includes a chuck for receiving the drilling element) toward any away from the case. This mechanism may comprise a “two-stage” linear mast M having an extendable roof jack J with one or more rods R that are received in a base B. The rods R may support the drill guide  10  at the distal end adjacent the face in use. The drill guide  10  may alternatively or additionally be provided on the base B to lend intermediate support, or elsewhere in the drilling path, without limitation. 
         [0031]    The base B supports an elongated bearing member G (such a beam), which in turn carries the drill D during movement toward and away from the mine face (compare  FIGS. 2 ,  3 , and  4 ) in response to the activation of an onboard feed mechanism E, which may comprise a chain drive, linear cylinder, or the like. The bearing member G may also be adapted for moving toward and away from the face (compare  FIG. 1  and  FIG. 4 ), and thus may be mounted to the base B so as to permit movement in a linear path in the desired direction. 
         [0032]    Turning to the plan views of  FIGS. 5 and 6 , the details of one possible embodiment of a drill guide  10  are shown. The drill guide  10  may comprise a support  12  in the form of a plate having a major surface generally parallel to the plane of the face to be worked. This plate  12  includes a peripheral notch  12   a  arranged for receiving the drilling element. Positioned adjacent to the notch  12   a  is a keeper for keeping the drilling element in the space provided. In one embodiment, this keeper may comprise a holder  14  serving as a first jaw for temporarily holding the drilling element in place before and during the time it is advanced toward and into the face to form the borehole. 
         [0033]    In the active position, the holder  14  includes a first end having a notch  14   a  adapted for receiving the drilling element and retaining it within the corresponding notch  12   a  of the plate  12 , which may be considered to form a second jaw. As should be appreciated, these jaws lie in different, but adjacent, horizontal planes, thus forming a scissor-like arrangement. The notches  12   a,    14   a  are shown as being generally V-shaped, but of course could be round, square, or have other shapes while achieving the desired holding function for the drilling element. 
         [0034]    As should be appreciated, it is desirable to arrange the drill guide  10  for ready retraction to admit the drilling element, and then activation to hold the drilling element in place. To achieve this, the holder  14  in the illustrated embodiment is mounted for pivoting movement relative to the plate  12  between an open position for allowing notch  14   a,  which is generally U-shaped, to receive the drilling element ( FIG. 5 ) and a closed position ( FIG. 6 ) for confining the drilling element within notch  12   a.  The primary pivot point for the holder  14  is designated as P 1 . 
         [0035]    To provide the movement between these positions, the holder  14  connects with a retainer, which in the illustrated embodiment includes a linear actuator in the form of a hydraulic cylinder  16 . This may involve connecting the holder  14  to the rod  16   a  of the cylinder  16  in a manner that allows for relative pivoting movement (designated as P 2 ). The case  16   b  may also be connected to a support, such as plate  12 , in a manner that allows for pivoting movement in the same general plane as the holder  14 . The pivot point for the cylinder  16  is designated as P 3 . 
         [0036]    Depending on the arrangement, it may be desirable to define the boundaries of relative lateral movement of the holder  14 . This may be achieved using stops  18 ,  20 , with the first stop  18  corresponding to the open condition and the second stop  20  corresponding to the closed condition. The stops  18 ,  20  may comprise extendable, threaded bolts journaled in a support structure, which thus can be adjusted as necessary to provide an engagement surface for the corresponding portion of the holder  14  in the illustrated embodiment. However, it should be appreciated that the stops could also engage the cylinder  16  or other associated structures to achieve a similar result. 
         [0037]    The retainer may include a biasing element for urging the holder  14  toward the retracted or active condition, depending on the mode of use. In the illustrated embodiment, the biasing element comprises a coil spring  16   c  contained within the case  16   b  of the cylinder  16  that normally urges the rod  16   a  in a direction along the longitudinal axis L. As will be understood upon reviewing the description that follows, the biasing or spring force along the axis L is selected so that it retains the holder  14  in the active or retracted position, but can be overcome with the application of only manual effort to extend or retract the rod  16   a  when the cylinder  16  is not pressurized. In use, the holder  14  may be considered initially in the open position, as shown in  FIG. 5 . As should be appreciated, the biasing force aligned with axis L is offset from pivot point P 1 . Thus, it creates a moment that keeps the holder  14  in the open condition, with stop  18  engaged. 
         [0038]    Once associated with the drilling element (shown in cross-section as element T in the plan view  FIG. 6 ), the holder  14  may be rotated toward the closed position, at which point the biasing force aligned with axis L is overcome and the linkage moves past the over center or equilibrium position until engagement with stop  20  is made. The moment about pivot point P 2  created by the spring force keeps the holder  14  in the closed condition. In this position, the drilling element is captured in the substantially aligned notches  12   a,    14   a,  and the drilling operation may proceed. 
         [0039]    Once the holder  14  is closed, the keeper or retainer is used to maintain the linkage in the corresponding position. This may be achieved by using a controller for controlling the supply of pressurized fluid from a remote source. In its most basic form, the controller may comprise a valve V (which may include a two position, three way spring return valve). The valve V may be actuated when a corresponding pilot signal is received, which may be activated by a push button or the like. 
         [0040]    Alternatively, the pilot signal may automatically issue. For example, the signal may be generated once corresponding signals for feeding and for rotating the drill are provided to a feed and rotation controller C associated with the valve V. The feed and rotation signals may be generated by one or more input devices I (e.g., one or more joysticks, buttons, or the like, positioned at a control panel or elsewhere on an associated mine vehicle, generally away from the location on the face where the borehole is being formed). 
         [0041]    This optional requirement for feed and rotation signals before activation of the cylinder  16  helps to assure that the operator is clear of the drill guide  10  after the manual closing operation is completed. Likewise, the pressure may be maintained on the cylinder  16  until both signals for causing feed and rotation of the drill D are removed. This prevents the operator from manually opening the drill guide  10  by moving the holder  14  while either feed or rotation is occurring. 
         [0042]    Once feed and rotation signals are removed (usually meaning the borehole is complete and the drill D has been retracted fully from the face), the holder  14  may be manually moved to the open position. The drilling element L may then be withdrawn from the guide  10 , such as by removing it from the notch  14   a  of holder  14 . If desired, the operation may then be repeated with an anchor element, such as a roof bolt. 
         [0043]    Another embodiment of an improved drill guide  100  is shown in  FIGS. 7-9 . The drill guide of this embodiment includes a pair of jaws  102   a ,  102   b  mounted for movement toward and away from each other in a plane generally transverse to the direction of feed of the drill D. The jaws  102   a ,  102   b  may be sandwiched between a pair of spaced plates  104   a,    104   b,  and mounted for relative pivoting movement about pivot points P and in a common plane. 
         [0044]    An actuator  106  is provided for actuating the jaws  102   a,    102   b  to move between a first, closed position ( FIG. 8 ) for gripping an object and a second, open position ( FIG. 9 ). The actuator  106  in the illustrated embodiment comprises a linear actuator, such as a hydraulic cylinder, which is provided spaced apart from the jaws  102   a,    102   b  and plates  104   a,    104   b.  This advantageously allows for the fluid supply lines to be located away from the drill guide  100 , mast, and other moving components. Specifically, in the illustrated embodiment, one or more conduits (e.g., hoses H or telescoping cylinders providing internal fluid delivery and return passages) may be provided along a sidewall of the mast. 
         [0045]    To convert the linear movement into rotational movement, the actuator  106  may connect with a rotary member, such as an elongated shaft or rod  108 , journaled between or adjacent the drill guide  100 , such as through plates  104   a,    104   b.  A linkage  110  may connect the rod  108  to one of the jaws  102   a ,  102   b,  such as jaw  102   b,  which in turn may be connected by a link  112  to the other jaw, such as jaw  102   a.  In this manner, rotation of the rod  108  causes the jaws  102   a,    102   b  to open and close, and shown in  FIGS. 8 and 9 , respectively. 
         [0046]    In accordance with a further aspect of the disclosure, it is also a desirable option to provide a drill guide  200  including a guard  204  having a guide  206  for guiding the drilling element into the proper position for being gripped, while assisting in preventing the operator&#39;s hands from being inadvertently positioned in the path of movement of the gripping jaws  202   a ,  202   b.  In the embodiment illustrated in  FIG. 10 , the guard  204  comprises at least one, and preferably a pair of spaced, generally parallel plates  208 ,  210  mounted to and forming an integral part of the guide  200 . The plates  208 ,  210  may be spaced apart a distance slightly greater than the height of the jaws  202   a,    202   b  in the same (vertical) direction. Each of these plates  208 ,  210  includes a slot  212  having an open end for receiving the drilling element and a closed end adjacent to the location where the gripping jaws  202   a,    202   b  close over the drilling element in the operative position. The slots  212  may be non-linear and, specifically, may be generally L-shaped, but could take other forms including for example C-shaped, U-shaped, serpentine, or the like. In any case, the slots  212  are dimensioned so as to only slightly exceed the diameter of the portion of the drilling element adapted to be gripped by the jaws  202   a,    202   b.    
         [0047]    In use, the operator may manually insert the drilling element into the open end of the labyrinth path of guide  206  and along the slots  212  to the position for being gripped. As should be appreciated, the arrangement is such that the operator&#39;s hands may be positioned above or below the plates  208 ,  210 , but generally not in the space between them (in which space the gripping ends of the jaws  202   a,    202   b  are located). Consequently, the guard  204  helps to prevent contact between the jaws  202   a,    202   b  and the operator, should inadvertent actuation occur. The path formed by the guard  204  also helps to position the drilling element properly for gripping by the jaws  202   a,    202   b , especially when the closed end of guide  206  corresponds to the location where gripping occurs. 
         [0048]    The foregoing descriptions of various embodiments are provided for purposes of illustration, and are not intended to be exhaustive or limiting. Modifications or variations are also possible in light of the above teachings. The embodiments described above were chosen to provide the best application to thereby enable one of ordinary skill in the art to utilize the disclosed inventions in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations (including the combination of any or all of the embodiments disclosed into a single apparatus) are within the scope of the invention.

Summary:
An apparatus for use in connection using a drill having a drilling element for forming a borehole in a face of a mine passage includes a drill guide for engaging the drilling element while permitting the drilling element to move toward the face for forming the borehole. The drill guide includes a keeper for keeping the drilling element in a desired position, which keeper is biased for pivoting movement upon the application of a manual force between an active position for capturing the drilling element and a retracted position for releasing the drilling element. A low profile drill guide is also disclosed, as is a guard for a drill guide, and also related methods.