Abstract:
A die grinder including a body having a longitudinal axis, and a grinding head portion with an output shaft capable of powered rotation. A motor is disposed in the body for rotating the output member. A locking interconnect portion attaches the grinding head portion to the body and is adapted to permit selective rotation of the grinding head portion relative to the body about the longitudinal axis of the body. Thus, the grinding head can be positioned at different selected angles relative to the body.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. application Ser. No. 11/279,180, filed Apr. 10, 2006 which is the non-provisional of U.S. Provisional Application No. 60/727,074 filed Oct. 14, 2005, the entireties of which are herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to die grinders and, more specifically, to a die grinder tool having a rotatable head. 
     Powered die grinders such as pneumatic die grinders rotate an output member with a grinder head for smoothing, shaping, and/or polishing metal surfaces. In general, pneumatic die grinders have a cylindrical housing designed to be held in a user&#39;s hand such that the user&#39;s fingers engage a trigger lever pivotally secured at a lower portion of the housing. In this way, the user can easily operate the grinder (i.e., depress the trigger lever) by squeezing the trigger lever with her fingers. 
     The trigger lever is typically located on the same side of the grinder as the output member. Therefore, to maneuver the grinder so that the grinding head on the output member engages a surface being worked, the user has to adjust her wrist or arm or entire body to properly position the tool. However, in some situations, such as when the user is trying to work on a surface that is hard to reach and/or is partially obstructed by other components or structures, there may not be enough space or room to adjust her wrist or arm or body. Thus, the user may have to change his or her grip on the tool, such as by improperly placing the palm of her hand over the trigger instead of her fingers. Changing the grip in this manner, however, makes it more difficult to both control the ratchet and squeeze the trigger lever. 
     SUMMARY OF THE INVENTION 
     In one aspect, a die grinder tool generally comprises a body having a longitudinal axis and a die grinder head including a rotary mechanism with an output member capable of powered rotation. A motor disposed in the housing is operatively connected to the rotary mechanism for rotating the output member. A locking interconnect for attaching the die grinder head to the body is adapted to permit rotation of the head relative to the body about the longitudinal axis of the body. 
     In another aspect, a pneumatic die grinder tool comprises a body having a longitudinal axis and a die grinder head including a rotary mechanism with an output member capable of powered rotation. An air motor disposed in the body is operatively connected to the rotary mechanism for rotating the output member. An air inlet is adapted to be coupled with a source of pressurized air for powering the air motor. A coupling for attaching the die grinder head to the body is adapted to permit rotation of the die grinder head relative to the body about the longitudinal axis of the body. 
     In a further aspect, a powered tool generally comprises a body having a longitudinal axis and a head including a rotary mechanism with an output member capable of powered rotation. A motor disposed in the body is operatively connected to the rotary mechanism for rotating the output member. A locking interconnect for attaching the head to the body is adapted to selectively permit rotation of the head relative to the body generally about the longitudinal axis of the body. 
     Other objects and features will be in part apparent and in part pointed out hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a longitudinal section of an embodiment of a die grinder according to the invention; 
         FIG. 2  is an enlarged fragment of  FIG. 1  showing the grinding head portion and locking interconnect portion of the die grinder shown in  FIG. 1 ; 
         FIG. 3  is a section of a grinding head housing used in the die grinder; 
         FIG. 4  is a side elevation thereof; 
         FIG. 5  is a top plan view thereof; 
         FIG. 6  is a side elevation of a driveshaft of the die grinder; 
         FIG. 7  is an end elevation of the driveshaft; 
         FIG. 8  is a section of a body closure member of the die grinder; 
         FIG. 9  is an end elevation of the body closure member; 
         FIG. 10  is a section of an end cap used in the die grinder; 
         FIG. 11  is an end elevation of the end cap; 
         FIG. 12  is a side elevation of an inner sleeve used in the die grinder; 
         FIG. 13  is an end elevation of the inner sleeve; 
         FIG. 14  is an enlarged, detail of the circled portion of  FIG. 12 ; 
         FIG. 15  is a section of an outer sleeve of the die grinder; 
         FIG. 16  is an enlarged, detail of the circled portion of  FIG. 15 ; 
         FIG. 17  is a side view, partially in section, of an end ring of the die grinder; 
         FIG. 18  is an enlarged, fragmentary section similar to  FIG. 2  but showing a die grinder having a different locking interconnect portion; 
         FIG. 19  is a section of a retaining ring of the die grinder of  FIG. 18 ; and 
         FIG. 20  is a section of a release cap of the die grinder of  FIG. 18 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A die grinder  10  according to the invention is illustrated in  FIGS. 1-17 . As shown in  FIG. 1 , the die grinder  10  includes a generally cylindrical body  12 , a grinding head portion  14 , and a locking interconnect portion  16  which permits the angle of the grinding head portion  14  relative to the body  12  to be reoriented. In the illustrated embodiment, the die grinder  10  is a pneumatic die grinder. As such, the die grinder  10  includes within the body  12  air motor components that are illustrated but not described in detail herein (because such components are within the range of knowledge of those having skill in the art), including an air inlet  18  configured to be connected to a source of pressurized air; a trigger  20  and pneumatic valve assembly  22 ; and a spindle  24  that is caused to rotate at high speed by the flow of pressurized air. It will be appreciated, however, that other means for powering the die grinder, e.g., an electric motor, may be employed without departing from the scope of the invention, as will be appreciated by those having skill in the art. 
     As further illustrated in  FIGS. 1-5 , the grinding head portion  14  of the die grinder  10  includes a grinding head housing  26 , which includes a generally cylindrical grinding head housing body  28  and a generally cylindrical grinding head coupling tube  30  that intersects the grinding head housing body  28  at a right angle. The grinding head housing body  28  and the grinding head coupling tube  30  are both hollow, such that a generally L-shaped passage  32  is defined through the grinding head housing  26 , and external threads  33  are formed on an exterior surface of the grinding head coupling tube  30 . An output shaft  34 , which may be of two-piece construction, is supported for rotation within the grinding head housing body  28 , e.g., by bearings  36  and  38 , and a grinding head  40  is disposed at the distal end of the output shaft  34  in any suitable manner. A bevel gear  42  is mounted on and surrounds the output shaft  34  at a generally medial location, also in any suitable manner. 
     Furthermore, a rotary power transmission mechanism housed within the grinding head coupling tube  30  couples the spindle  24  to the output shaft  34  such that rotation of the spindle causes rotation of the output shaft  34 . In particular, a driveshaft  44  ( FIGS. 1 ,  2 ,  6 , and  7 ) is supported for rotation within the grinding head coupling tube  30 , e.g., by bearings  46  and  48 . A slot  50  is formed in the proximal end of the driveshaft  44 , and a generally rectangular spindle extension  52  is received within the slot  50  to couple the spindle  24  to the driveshaft  44 . A generally frustoconical driveshaft head  54  is formed at the opposite, distal end of the driveshaft  44 , and a bevel gear  56  is formed around the circumference of the driveshaft head  54 . The bevel gear  56  on the driveshaft head  54  engages the bevel gear  42  surrounding the output shaft  34  such that rotation of the spindle  24  and driveshaft  44  about a first axis of rotation causes rotation of the output shaft  34  and grinding head  40  about a second axis of rotation that is oriented at an angle (e.g., 90°) relative to the first axis of rotation, as will be understood by those having skill in the art. 
     As noted above, the locking interconnect portion  16  is configured to permit the angle of the grinding head portion  14  relative to the body  12  to be selectively reoriented. The mechanism which facilitates that feature will now be described with reference to  FIGS. 1 ,  2 , and  8 - 17 . 
     As shown in  FIGS. 1 and 2 , a generally cup-shaped body closure member  58  is received within the open distal end of the body  12 . As shown in greater detail in  FIGS. 8 and 9 , the body closure member  58  includes an annular end wall  60  and a cylindrical tube  62  (broadly, a capture member) extending from the end wall  60 . The end wall  60  has a central hole  64  through which the spindle  24  passes, and the outer diameter of the end wall  60  is greater than the outer diameter of the cylindrical tube  62  so as to form a circumferential shoulder  66 . Insertion of the body closure member  58  into the open distal end of the body  12  is limited by abutment of end wall  60  against air motor sleeve  68 . 
     The body closure member  58  is retained in position by means of an end cap  70 . As shown in  FIGS. 10 and 11 , the end cap  70  includes a cylindrical tube  72  and a scalloped flange  74  at a distal end of the cylindrical tube. The cylindrical tube  72 , which is internally sized to fit over the cylindrical tube  62  of the body closure member  58 , has external threads  76  formed thereon, and the open distal end of the body  12  has internal threads (not labeled) formed therein. Thus, the end cap  70  is screwed down into the open distal end of the body  12 , e.g., by means of the scalloped flange  74 , and the inner edge of the cylindrical tube  72  bears against the shoulder  66  of the body closure member  58  to secure the body closure member  58  against the spacer member  68 . Other means for securing the body closure member  58  within the distal end of the body  12 , e.g., crimping, are possible without departing from the scope of the invention. 
     As further shown in  FIG. 8 , a plurality of capture holes  78  extend through the cylindrical tube  62  of the body closure member  58 . The capture holes  78  are all equally spaced from the end  80  of the cylindrical tube  62 , and they are evenly spaced angularly about the circumference of the cylindrical tube  62 . As the die grinder  10  is illustrated in the various figures, there are four capture holes  78  formed in the cylindrical tube  62  (only two being visible in  FIG. 8 ), but more or fewer capture holes  78  may be provided without departing from the scope of the invention. As will become more readily apparent in view of the further disclosure below, the number of angular positions of the grinding head portion  14  relative to the body  12  is the same as the number of capture holes  78 . 
     As further shown in  FIGS. 1 and 2 , a generally tubular inner sleeve  82  (broadly, a seating member) fits within the cylindrical tube  62  of the body closure member  58 . As shown in greater detail in  FIGS. 12-14 , the inner sleeve  82  is generally cylindrical and includes an annular channel  83  on its exterior surface. Within the channel  83  at spaced apart locations are a plurality of seating dimples  84 . The seating dimples extend radially inward from the floor of the channel  83  and provide seating surfaces for a number of locking spheres  86  (referred to broadly as catches), the function of which will be described in more detail below. There is the same number of seating dimples  84  as capture holes  78 , and like the capture holes  78 , the seating dimples  84  are evenly spaced within the channel  83  angularly about the circumference of the inner sleeve  82 . 
     Furthermore, external threads  88  are formed on the external surface of the inner sleeve  82  at a distal end thereof, and internal threads  90  are formed on the inner surface of the inner sleeve  82  near the distal end thereof, but axially spaced slightly inwardly from the distal end of the inner sleeve  82 . The distal end of the inner sleeve  82  (particularly, the interior surface thereof) and the grinding head coupling tube  30  (particularly, the exterior surface thereof) are cooperatively configured such that the grinding head coupling tube  30  screws into the distal end of the inner sleeve  82 , with the external threads  33  on the grinding head coupling tube  30  engaging the internal threads  90  at the distal end of the inner sleeve  82 . 
     As further illustrated in  FIGS. 1 and 2  (which show the die grinder  10  with the grinding head portion  14  locked with respect to the body  12 ), a locking sphere  86  is positioned in each of the capture holes  78  in the cylindrical tube  62  of the body closure member  58 , and each locking sphere  86  protrudes radially inwardly all the way through its respective capture hole  78 . Thus, each locking sphere  86  seats within a respective seating dimple  84  on the exterior surface of the inner sleeve  82 . The capture holes  78  can be slightly larger in diameter than the locking spheres  86 , but not so large that the locking spheres roll around loosely therein. 
     A movable outer sleeve  92  (broadly, a retaining member) surrounds the cylindrical tube  62 , as shown in  FIGS. 1 and 2 . As shown in greater detail in  FIGS. 15 and 16 , the outer sleeve  92  is a generally cylindrical tube, with a ridge  94  extending radially inwardly from an inner surface thereof at a generally medial axial position. The ridge  94  suitably has a beveled camming surface  96 , the benefit of which will be made clearer below. The inner diameter of the portion of the outer sleeve  92  that is located distally of the ridge  94  (i.e., to the left of the ridge as shown in  FIG. 15 ) is greater than the outer diameter of the cylindrical tube  62  such that a first annular space  98  is formed between the cylindrical tube  62  and the outer sleeve. Similarly, the inner diameter of the portion of the outer sleeve  92  that is located proximally of the ridge  94  (i.e., to the right of the ridge  94  as shown in  FIG. 15 ) is greater than the outer diameter of the cylindrical tube  62  such that a second annular space  100  is formed between the cylindrical tube  62  and the outer sleeve  92 . The distalmost end of the outer sleeve  92  is slightly flared, such that the inner diameter thereof is larger than the inner diameter of the rest of the outer sleeve  92 . 
     An end ring  102  is further provided. As shown in  FIG. 17 , the end ring  102  is a generally thin hat-shaped member with a central hole  104 , and internal threads  106  are formed around the central hole  104 . The end ring  102  is threaded onto the distal end of the inner sleeve  82 , with internal threads  106  engaging the external threads  88  on the distal end of the inner sleeve  82 . The end ring  102  is positioned in abutment with the distalmost surface of the inner sleeve  82 . The end ring limits the amount the movable outer sleeve  92  can be moved. A screw  108  in the back of the grinding head portion  14  is engageable with the end ring  102  to maintain spacing between the end ring and the movable outer sleeve  92  so that the outer sleeve cannot be moved toward the grinding head  14  so far that the locking spheres  86  might fall out. Other ways of maintaining such a maximum spacing do not depart from the scope of the present invention. 
     A helical spring  112  is provided within the first annular space  98 , surrounding the cylindrical tube  62  of the body closure member  58 . The helical spring  112  is disposed between and bears against the end ring  102  at one end and a bearing surface  104  on the ridge  94  within the outer sleeve  92  at its opposite end. Thus, the helical spring  112  biases the moveable outer sleeve  92  proximally (i.e., to the right as shown in  FIGS. 1 and 2 ), with proximal movement of the outer sleeve  92  limited by abutment of the outer sleeve  92  with the flange  74  of the end cap  70 . 
     The position of the outer sleeve  92  shown in  FIGS. 1 and 2  is a locking position thereof, and the various components are mutually sized and configured such that ridge  94  surrounds and bears against the locking spheres  86  when the outer sleeve  92  is in the locking position. In that position, the ridge  94  secures the locking spheres  86  in the seating dimples  84 . Thus, the locking spheres  86  prevent the inner sleeve  82 —and hence the grinding head coupling tube  32 , which is screwed into the distal end of the inner sleeve  82 —from rotating within the cylindrical tube  62  of the body closure member  58  about the longitudinal axis of the die grinder  10 . 
     To change the angular orientation of the grinding head portion  14  (i.e., to rotate it about the longitudinal axis of the die grinder  10 ), the outer sleeve  92  is moved distally (i.e., to the left, as shown in  FIGS. 1 and 2 ) against the biasing force of the helical spring  112  to an unlocking position. Distal movement of the outer sleeve  92  is limited by abutment and registration of the flared distal end of the outer sleeve  92  with the end ring  102 . Such distal movement of the outer sleeve  92  removes the ridge  94  from overlying the locking spheres  86 . At that point, the grinding head portion  14  may be rotated about the longitudinal axis of the die grinder  10 , which rotation causes the inner sleeve  82  to rotate within the cylindrical tube  62 . As the inner sleeve  82  rotates within the cylindrical tube  62 , the body structure of the inner sleeve  82  surrounding the seating dimples  84  forces the locking spheres  86 —which are restrained against circumferential movement by the capture holes  78 —to move radially and rise up out of the seating dimples  84 , thus to protrude slightly into the second annular space  100  between the outer sleeve  92  and the cylindrical tube  62 . It will be appreciated that the second annular space  100  is large enough to permit the locking spheres  86  to rise completely out of and clear the seating dimples  84 , yet small enough to prevent the locking spheres from passing radially completely out of the channel  83  or the capture holes  78 . Thus, the inner sleeve  82  will be freed to rotate beneath the locking spheres  86  when the outer sleeve  92  is moved distally. 
     Once the grinding head portion  14  has been rotated to the desired angular position, the outer sleeve  92  is released, and the helical spring  112  biases it back toward the locked position. The camming surface  96  of the ridge  94  will bear against the locking spheres  86 , thus pushing the locking spheres out of the second annular space  100  and back down into the seating dimples  84 . Thus, the grinding head portion  14  will once again be locked in its new angular position. From the foregoing, it will be appreciated that the mechanism by means of which the grinding head portion is released and secured is essentially a locking detent mechanism. 
     Referring now to  FIG. 18 , a fragmentary portion of a die grinder  210  similar to the die grinder  10  of  FIG. 1  is shown. Corresponding parts of the die grinder  210  will be given the same reference numerals as for the die grinder  10 . Moreover, the construction of many parts of the die grinder  210  which are the same in the illustrated embodiment as that of die grinder  10  will not be described again. A primary distinction between the die grinder  210  and the die grinder  10  is in the construction of the locking interconnect portions ( 216  and  16 ). It is to be understood that there can be other differences between the grinder  210  and the grinder  10  without departing from the scope of the present invention. 
     The locking interconnect portion  216  includes a locking sphere  286  positioned in each of the capture holes  278  in the cylindrical tube  262  of the body closure member  258 , and each locking sphere protrudes radially inwardly all the way through its respective capture hole. Thus, each locking sphere  286  seats within a respective seating dimple  284  on the exterior surface of the inner sleeve  282 . In that regard, the construction is closely similar to that of die grinder  10 . 
     A movable retaining ring  292  (broadly, a retaining member) surrounds the cylindrical tube  262 . As shown in greater detail in  FIG. 19 , the retaining ring  292  has a ridge  294  extending radially inwardly from an inner surface thereof at a generally medial axial position. The ridge  294  has a beveled camming surface  296  immediately adjacent to the ridge, the benefit of which will be made clearer below. The inner diameter of the portion of the retaining ring  292  that is located proximally of the ridge  294  (i.e., to the right of the ridge  294  as shown in  FIG. 19 ) is greater than the outer diameter of the cylindrical tube  262  such that an annular space  300  ( FIG. 18 ) is formed between the cylindrical tube and the retaining ring. It will be appreciated that the retaining ring  292  differs from the movable outer sleeve  92  in that the structure of the sleeve distal of the ridge  94  is not present in the retaining ring. Moreover as will be described more fully, the retaining ring  292  is not located in an (outer) position where it can be grasped and moved by the user. 
     In place of the end ring  102  of the die grinder  10 , the die grinder  210  has a tubular release cap  302 . As shown in  FIG. 20 , the release cap  302  has a generally inverted cup shape with a central hole  304 , and internal threads  306  are formed around the central hole. The release cap  302  is threaded onto the distal end of the inner sleeve  282 , with internal threads  306  engaging external threads  288  on the distal end of the inner sleeve  282 . The release cap  302  has an interior cavity that is larger in diameter than the cylindrical tube  262  of the closure member  258  to define an annular space  298 . 
     A helical spring  312  provided within the annular space  298  is disposed between and bears against the release cap  302  at one end and a bearing surface  305  on the retaining ring  292 . Thus, the helical spring  312  biases the retaining ring  292  proximally (i.e., to the right as shown in  FIG. 18 ). In this configuration, the retaining ring  292  is in a locking position in which the ridge  294  surrounds and bears against the locking spheres  286 . In the locking position, the ridge  294  secures the locking spheres  286  in the seating dimples  284 . Thus, the locking spheres  286  prevent the inner sleeve  282 —and hence the grinding head coupling tube  232 , which is screwed into the distal end of the inner sleeve  282 —from rotating within the cylindrical tube  262  of the body closure member  258  about the longitudinal axis of the die grinder  210 . 
     To change the angular orientation of the grinding head portion  214  (i.e., to rotate it about the longitudinal axis of the die grinder  210 ), the release cap  302  is unscrewed so that it moves distally (to the left as seen in  FIG. 18 ) relative to the retaining ring  292 . This movement increases the axial length of the space  298  in which the spring  312  resides. Thus, the spring force exerted by the spring  312  on the retaining ring  292  is reduced. When a torque is subsequently applied to turn the head  232  the locking spheres are subject to a force radially outward from the retaining holes  278  and dimples  284 . The locking spheres  286  bear against the retaining ring  292 . The reduced force of the spring  312  allows the retaining ring  292  to move distally. This movement is aided by engagement of the locking spheres  286  with the camming surface  296 . 
     Such distal movement of the retaining ring  292  removes the ridge  294  from overlying the locking spheres  286 . At that point, the grinding head portion  214  may be rotated about the longitudinal axis of the die grinder  210 , which rotation causes the inner sleeve  282  to rotate within the cylindrical tube  262 . As the inner sleeve  282  rotates within the cylindrical tube  262 , the body structure of the inner sleeve surrounding the seating dimples  284  forces the locking spheres  286 —which are restrained against circumferential movement by the capture holes  278 —to move radially and rise up out of the seating dimples, thus to protrude slightly into the annular space  300  between the outer sleeve  292  and the cylindrical tube  262 . It will be appreciated that the annular space  300  is large enough to permit the locking spheres  286  to rise completely out of and clear the seating dimples  284 , yet small enough to prevent the locking spheres from passing radially completely out of the capture holes  278 . Thus, the inner sleeve  282  is freed to rotate beneath the locking spheres  286  when the retaining ring  92  is moved distally. 
     Once the grinding head portion  214  has been rotated to the desired angular position, the release cap  302  is screwed back down (proximally) to the position shown in  FIG. 18 . This reduces the axial length of the space  298  and compresses the spring  312  against the retaining ring  292  pushing the ring back toward the locking position. The camming surface  296  of the ridge  294  bears against the locking spheres  86 , pushing them out of the annular space  300  and back down into respective seating dimples  284 . Thus, the grinding head portion  214  will be locked in its new angular position against rotation. The spring force of the spring  312  is now too great to permit the retaining ring  292  to be moved distally under an applied torque on the head portion  214 . 
     When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
     As various changes could be made in the above without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.