Abstract:
An apparatus for facilitating use of a rotary tool such as a grinder or the like in working on surfaces around bends or within a cavity utilizes a protective sheath of selectable length that is releasably held to the body of the rotary tool and provides a passage way for the flexible drive extender. The protective sheath can be configured by the user to meet his needs.

Description:
[0001]    The present application claims priority from provisional patent application No. 61/144937 filed Jan. 15, 2009. 
     
    
       [0002]    The present invention relates to the field of rotary tools such as grinders or drills. More specifically, the present invention is an adaptor and flexible drive extender to facilitate utilization of a rotary tool around bends or inside cavities. 
       SUMMARY OF THE INVENTION 
       [0003]    It is an object of the present apparatus to utilize only one hand while directing the work implement of a rotary tool in hard to reach places such as around bends and inside cavities. 
         [0004]    It is a further object of the apparatus to improve the safety of a rotary tool incorporating a flexible drive extender. 
         [0005]    The present embodiment of the apparatus accomplishes these and other objects of the designer by providing a protective sheath that is held to the body of the rotary tool and provides a passage way for the flexible drive extender which can be configured by the user to meet his needs. 
         [0006]    These and other objects and advantages of the invention will become apparent from the following detailed description of the apparatus. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    An embodiment of the flexible rotary tool attachment is depicted in the accompanying drawings which form a portion of this disclosure and wherein: 
           [0008]      FIG. 1  is an exploded side elevation view of a first embodiment of the apparatus; 
           [0009]      FIG. 2  is a pictorial side elevation view of the apparatus attached to a rotary tool; 
           [0010]      FIG. 3  is a pictorial side elevation view of the apparatus partially detached from the rotary drive unit with the flexible drive extender attached to the rotary drive unit; and, 
           [0011]      FIG. 4  is an exploded side elevation view of a second embodiment of the apparatus. 
           [0012]      FIG. 5  is an exploded side elevation view of a third embodiment of the apparatus. 
           [0013]      FIG. 6  is a side elevational view of the housing adapter of the present invention; 
           [0014]      FIGS. 7   a  and  7   b  are side elevational view of terminal tool mandrels, 
           [0015]      FIGS. 8   a  and  8   b  are pictorial views showing a portion of the apparatus in various stages of assembly with an adapter with internal female threads; 
           [0016]      FIGS. 9   a  and  9   b  are pictorial views showing apparatus in various stages of assembly at the terminal end; 
           [0017]      FIG. 10  is a pictorial view of an adapter with external male threads; 
           [0018]      FIG. 11  is a pictorial perspective view of an adapter with a compression fitting holding the housing to rotary tool; 
           [0019]      FIGS. 12   a  and  12   b  are pictorial views of a sample terminal tool 
           [0020]      FIG. 13  is a pictorial of sample flex configurations with an array of terminal tools. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0021]    Referring to the  FIGS. 1-13  for a clearer understanding of the invention, it may be seen that the present embodiment of the invention contemplates attachment to a grinder  11  or other rotary drive unit, which may be a fluid powered drive, an air powered drive, or an electrical drive. Regardless of the motive power of the grinder, it is contemplated that the grinder  11  will have a rotary output including an output chuck  11   a  and a threaded connector  11   c  having a male thread formed thereon for attachment of various shields and peripheral items. Threaded connector  11   c  is affixed or integral to the grinder  11  or a housing on the grinder  11  and is coaxial with chuck  11   a . Other connections, such as a bayonet connection or a snap-lock connection may be used when appropriate for the interface between the grinder  11  and the adapter  12  described hereinafter. 
         [0022]    A housing adapter  12  in the form of a hollow truncated cone is provided with internal female thread  12   a,  matingly compatible with threaded connector  11   e , formed at a tubular first end such that housing adapter  12  may be securely attached to grinder  11 . Other connections may be used as noted above. An opposite tubular end of housing adaptor  12  has a male thread  12   b  formed thereon. Between the first and opposite ends of housing adapter  12  the truncated cone is reduced in diameter from a size sufficient to engage female thread  12   a  on connector  11   c  to a smaller size sufficiently large enough to surround a protective sheath  13  which in turn has an internal diameter sufficient to allow free rotation of flexible drive extender  14  which may be a cable such as used in speedometer applications. 
         [0023]    Protective sheath  13  is preferably made of metal tubing that will not crush or wear prematurely due to internal contact with rotating flexible drive extender  14 , yet will be flexible enough to allow a user to bend it, such as with an elbow bend to facilitate working around corners or inside cavities. Preferably a radiused bend is formed in sheath  13  using a jig and internal mandrel, thereby reducing wear and resistance between drive extender  14  and the interior of sheath  13 . Protective sheath  13  should be strong enough that it can be slidingly received in adaptor housing  12  and secured there to using a collet  16 , nose piece  17  and nut  18  which threadedly engages male thread  12   c.  It is to be understood that the nose piece and nut can be integral. Tightening nut  18  onto male thread  12   c  in position over the nose piece  17  and collet  16  compresses collet  16  about sheath  13  and fixes sheath  13  radially and axially relative to tool  11 . 
         [0024]    Flexible drive extender  14  is releasably secured at one end in chuck  11  and rotates therewith in a conventional manner. The opposite end of flexible drive extender  14  terminates in a cable adapter such as a threaded spindle  19  proximal the end of sheath  13 . A terminal tool  20  such as a cutting point or abrasive point of any suitable shape and material for the project is conventionally attached to the spindle  19  or other cable adapter. The adjustable nature of the collet connection of sheath  13  to housing adapter  12  allows the effective length of the sheath  13  and flexible drive extender  14  to be matched to achieve proper positioning of the terminal tool  20  at the end of sheath  13 . 
         [0025]    That is to say, with the collet  16  and nut  18  sufficiently loosened, housing adapter  12  can slide along the length of sheath  13  to expose the chuck  11   a  such that flexible drive extender can be engaged and clamped in the chuck  11   a  at the length appropriate for the sheath  13 . The housing adapter  12  can then be tightened on to connector  11  c and the nut  18  tightened onto the housing connector to maintain the relative position of the sheath  13  and extender  14 . Thereafter an operator can use the implement to reach hard to reach surfaces such as an offset surface within a cavity or behind a flange. 
         [0026]    In  FIG. 4 , I illustrate a second embodiment of the invention which includes details to reduce friction and heating due to the moving parts. Specifically, rotary drive  11  is connected to driver extender  14  using a drive collet  31 , drive nose piece  32 , and drive nut  33  which combine to grip cable holder  41  which is attached to drive extender  14  using a pair of set screws  42 , as also shown in  FIGS. 8   a  and  8   b . Housing adapter  12  has an internal thread  12   c  which engages threaded connection  11 C. A nylon liner sheath  34 , which may be segmented, is coaxially disposed between drive extender  14  and protective sheath  13 . Head mandrel is connected to drive extender at its free end inside head coupler  35 , and the terminal end of the drive extender is supported for rotation on a pair of bearings  36  running on a brass spacer bar  37  as may be seen in  FIGS. 9   a  and  9   b . The terminal tool  20  is affixed to a head mandrel  39  which may have various configurations as shown in  FIGS. 7   a  and  7   b  as well as  FIGS. 12   a    12   b  and  13 . The head mandrel  39  shown in  FIG. 7   a  is knurled for mounting a terminal tool  20  thereto with cement. The head mandrel  39 ′shown in  FIG. 7   b  is flat to facilitate brazing terminal tool  20  thereon. 
         [0027]    Housing adapter  12  may have internal threads as shown in  FIG. 8   a  or external threads as shown in  FIG. 10 , depending on how rotary drive  11  is configured. Further, housing adapter  12  may use a compression fit to attach to rotary drive  11  as shown in  FIG. 11 . 
         [0028]    In  FIG. 5 , yet another embodiment of the invention is shown, with additional bearings  36  supporting the drive extender  14 . In this embodiment the drive extender is a heavier cable having a 0.125 outside diameter as opposed to a 0.042 outside diameter cable in the embodiment shown in  FIG. 4 . Likewise the nylon sheath  34 ′, spindle  19 , locking washer and head coupler are all somewhat more robust for a heavier duty application. 
         [0029]    The versatility of the apparatus is shown in  FIG. 13  wherein various configurations and terminal tools are illustrated. It is to be understood that the forms of the invention shown are preferred embodiments thereof and that various changes and modifications may be made therein without departing from the spirit of the invention or scope as defined in the following claims.