Patent Publication Number: US-6712368-B2

Title: Quick attachment release system for a rotary hand tool

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to power hand tools and more particularly to a power hand tool with a quick attachment release system. 
     Small rotary hand tools have been marketed for many years for use in carrying out woodworking and metal working tasks by hobbyists as well as commercial artisans. An example of such is produced by Dremel, which also produces many accessories for these rotary hand tools. Such small rotary hand tools are generally cylindrical in shape, and have a motor unit with a rotary output shaft that is adapted to connect to a number of accessories. The drive unit of many recent models of such rotary hand tools is relatively small, lightweight and capable of being easily used. The tool has a small but powerful electric motor that is capable of driving an output shaft at high speed, and a rotary implement can be typically attached to the tool&#39;s output shaft, which is axially aligned with the length of the tool. 
     There are several accessory attachments such a flexible cable, a grout removal guide or cutting guide, a chain saw sharpener among others, which are attached directly on the rotary hand tool for use. It is the current practice to attach these accessories by threadably mounting them onto the rotary hand tool. The problem with this method is that it is inconvenient and takes more time than is desired to screw the accessory on and off the rotary tool. Another disadvantage is that the accessory attachment often tends to rotate relative to the tool body during use or is not properly aligned for effective performance. 
     Accordingly, it is a primary object of the present invention to provide an improved rotary hand tool that includes a quick release attachment system that allows users to snap-fit an accessory attachment onto the rotary hand tool, yielding a quick engage/disengage feature. 
     Another object of the present invention is to provide an improved rotary hand tool that prevents rotation of the accessory attachment relative to the tool body during use and precisely aligns it for effective performance. 
     BRIEF SUMMARY OF THE INVENTION 
     The above-listed objects are met or exceeded by the present rotary hand tool with quick release attachment system, which features a snap-fit connection between the rotary hand tool and accessory attachments. A spring-loaded ball in a mating attachment engages a groove on the rotary hand tool, which yields a quick engage/disengage feature. 
     Another feature of the present rotary hand tool with quick release attachment system is a keying feature in the nose end portion of the rotary hand tool, which prevents the attachment from rotating relative to the tool body during use and precisely aligns it for effective performance. A non-circular shaped extension, which may include any polygonal, oval, or star shape, is configured on the nose of the tool, which mates with a complementary non-circular shape opening in the mating attachment. This prevents rotation of the mating attachment relative to the body of the tool. 
     More specifically, the present invention provides a rotary tool with a quick release attachment capability. The rotary tool has a housing that encloses a motor, and the housing has a central axis, a non-operational end portion and an operational end portion. There is a nose portion formed at the operational end portion, and the nose portion has an outer annular groove disposed generally perpendicularly of the axis. The nose portion also has a non-circular element at the outer end thereof parallel with the central axis. A rotatable shaft is connected to the motor and is located along the central axis. 
     The accessory attachment includes a central cavity, a mating and connection end portion and a working end portion. A non-circular mating element is formed in the central cavity that matingly engages the non-circular element of the rotary tool. There is also a biased mating and connection element provided on the accessory attachment, which faces the central cavity. This biased mating and connection element engages the annular groove of the nose portion when the accessory attachment is fitted onto the rotary tool. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a predominately perspective view of the rotary hand tool connected with the accessory attachment, embodying the present invention, which in this drawing is a grout removal guide; 
     FIG. 2 is a predominately front perspective view of the rotary hand tool shown in FIG. 1; 
     FIG. 3 is an end view of the operational end portion of the rotary hand tool, embodying the present invention; 
     FIG. 4 is a predominately side view of the hand tool shown in FIG. 2; 
     FIG. 5 is a perspective view of the present accessory attachment, which in this drawing is a grout removal guide; 
     FIG. 6 is a view of the connection end portion of the accessory attachment shown in FIG. 5; 
     FIG. 7 is a partial side view of a prior art rotary hand tool; 
     FIG. 8 is a predominately front view of a quick release attachment adaptor; 
     FIG. 9 is a predominately back view of the quick release attachment adaptor shown in FIG. 8; 
     FIG. 10 is a perspective view of a prior art accessory attachment, which in this drawing is a grout removal guide; and, 
     FIG. 11 is a perspective view of a quick release attachment adapter for the prior art accessory attachment shown in FIG.  10 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, the present rotary tool with a quick release accessory attachment is generally designated at  10 . The rotary tool alone is generally designated  12 , and includes a housing  14  that encloses a motor (not shown). As shown in FIG. 2, the housing has a central axis designated A—A, a non-operational end portion  18  and an operational end portion  20 . 
     As best shown in FIGS. 2 and 4, a nose portion  22  is formed at the operational end portion  20  and has an outer annular groove  24  disposed generally perpendicularly of the central axis A—A, and a non-circular element  26  at the outer end  28  thereof that is coaxial with the central axis. While it is preferred that the nose portion  22  be generally cylindrical in design, other designs for the nose portion are contemplated and may include any polygonal or oval shapes. In the preferred embodiment of the present invention, the non-circular element  26  is a square shaped extension, but it may be constructed in many non-circular shapes, including but not limited to any polygonal shape, star shape, oval, or plurality of teeth. An important consideration is that the shape be such that it can mate with a complementary shape of the accessory attachment to prevent relative rotational movement between the two. 
     A rotatable shaft  30  is connected to the motor along the central axis A—A, and a chuck  32 , well known in the prior art, is connected to the rotatable shaft  30 , and is used to hold different tools, such as a drill or other bit. 
     Referring to FIGS. 1 and 5, the present accessory attachment, indicated generally at  40 , includes a cylindrical cavity  42 , an mating and connection end portion  44  and a working end portion  46 . As shown in FIG. 6, a non-circular mating element  48  formed in the cylindrical cavity  42  matingly engages the non-circular element  26  of the nose portion  22 . In the preferred embodiment, the non-circular mating element  48  is a square shaped recess. However, the non-circular mating element  48  may be constructed in any non-circular shape, including but not limited to any polygonal shape, star shape, oval, or plurality of teeth. Importantly, the non-circular element  26  and the non-circular mating element  48  need to be complementary to each other to provide a keying feature. Having a keying feature with noncircular shapes such as these prevents rotation of the accessory attachment  40  relative to the rotary tool  12  and also provides precise alignment of the accessory attachment on the tool  12 . 
     As the number of sides on the non-circular element  26  and non-circular mating element  48  increase, so does the number of possible positions to matingly engage the keying feature. The greater number of possible positions may make it easier and quicker to fit the accessory attachment  40  onto the rotary tool  12  because less jostling may be needed. 
     In another embodiment of the present invention (not shown), the nose portion  22  may have a non-circular mating element  26  that is a recess, and the central cavity  42  of the accessory attachment  40  has a non-circular mating element  48  that is an extension. This embodiment operates in a similar manner to the preferred embodiment, with the keying feature of the recess and extension preventing rotation of the accessory attachment  40  on the rotary tool  12 . 
     Referring now to FIGS. 5 and 6, the accessory attachment  40  includes a biased mating and connection element  50  provided on the accessory attachment  40  facing the central cavity  42 . In the preferred embodiment, the biased mating and connection element  50  is a spring-loaded ball  52  that is retained by a resilient split circular ring  54  that fits in an exterior annular recess  56  of the accessory attachment  40 . The spring-loaded ball  52  is positioned in a hole  58  of the accessory attachment  40 , whereby a contacting portion of the ball is exposed in the central cavity  42 . The hole  58  is sized and shaped so that the ball cannot escape completely into the cavity  42 . Also, the ring  54  has a hole  60  that is smaller than the diameter of the ball  52  and since the ball also fits in the hole  58  of the accessory attachment  40 , the ring is prevented from rotating on the accessory attachment. 
     In operation, a user wanting to utilize an accessory accessory attachment  40 , such as the grout guide, simply snaps the accessory attachment onto the rotary tool  12 , so that the non-circular element  26  of the rotary tool matingly engages the non-circular mating element  48  of the accessory attachment, and the spring loaded ball  52  engages the annular groove  24 , locking the accessory attachment in place. In this regard, the resilient ring  54  is adapted to move outwardly a sufficient distance so that the ball  52  can move away from the cavity  42  so that the accessory attachment  40  can be reinserted. When it is inserted the required depth, the ball  52  will engage the groove  24  and be locked in position. To disconnect the accessory attachment  40  from the rotary tool  12 , the user pulls the accessory attachment away from the rotary tool, thereby disengaging the spring-loaded ball  52  from the annular groove  24 . The present quick release attachment system is user friendly in that it allows the user to change accessory attachments  40  quickly and easily. Also, the mating feature of the non-circular elements  26  and  48  prevents the accessory attachment  40  from rotating relative to the tool housing  14  during operation of the rotary tool  12 . 
     It is also contemplated that the present invention may be a quick release attachment adaptor, generally designated  70 , that can be attached to the prior art rotary tool  72 . As shown in FIG. 7, the rotary tool  72  includes a housing  74  enclosing a motor, the housing having a non-operational end portion  76  and an operational end portion  78  with threads  80  disposed thereon. The quick release attachment adaptor  70  would be adapted to connect to a rotary tool attachment  40 , such as the one described above. 
     Referring to FIGS. 8 and 9, the quick release attachment adaptor  70  includes an adaptor base  82  having a central bore  84 , a first end portion  86  and a second end portion  88 , with the first end portion attaching to the operational end portion  78  of the rotary tool  72 . It is preferred that the adaptor base  82  be generally cylindrical in design. An annular groove  90  disposed generally perpendicularly of the central bore  84  which matingly engages the biased mating and connection element  50 . There is also a non-circular element  92  formed at the outer end  94  of the second end portion  88  parallel with the central bore  84 . This non-circular element  92  matingly engages the non-circular mating element  48  of the attachment tool  40 . All of the variations that were discussed above with regard to the non-circular element  26  are applicable here, as they may all be constructed on the quick release attachment adaptor. 
     The central bore  84  has threads  96  disposed thereon, so that in operation the user would screw the quick release attachment adaptor  70  onto the threads  80  of the rotary tool  72 . Once in position, the user may then snap-fit the attachment tool  40  on the quick release attachment adaptor  70  in the same manner as described above. 
     Another embodiment of the present invention is a quick release attachment adaptor for a rotary tool attachment, which is generally designated  100 . Referring to FIG. 10, a prior art attachment tool  102  includes a threaded end portion  104  and a working end portion  106 . The quick release attachment adaptor for the attachment tool  100  is adapted to connect to a rotary tool  12 , as shown in FIG.  2  and previously discussed. Now referring to FIG. 11, included in the quick release attachment adaptor for the attachment tool  100  is an attachment adaptor base  108  having a central cavity  110 , a first end portion  112  and a second end portion  114 . It is preferred that the attachment adaptor base  108  be generally cylindrical. The first end portion  112  is attached to the threaded end portion  104  of the attachment tool  102 . 
     A non-circular mating element  116  formed in the central cavity  110  matingly engages the non-circular element  26  of the rotary tool  12 . All of the variations that were discussed above with regard to the non-circular mating element  48  are also applicable here, as they may all be constructed on the quick release attachment adaptor for the attachment tool  100 . 
     Also included on the quick release attachment adaptor for the attachment tool  100  is a biased attachment element  118  provided on the attachment adaptor base  108  facing the central cavity  110 . This biased attachment element  118  is a spring loaded ball, which is preferably the same as the spring loaded ball  52  discussed above, and therefore the details of the spring loaded ball  52  are applicable. 
     Still referring to FIG. 11, the attachment adaptor base  108  has threads  120  disposed thereon near the first end portion  112 , so that the user may screw the quick release attachment adaptor  100  onto the attachment tool  102 . Once in position, the user may then snap-fit the combined attachment tool  102  and quick release attachment adaptor  100  on the rotary tool  12 , in the same manner as described above. A user may also place the quick release attachment adaptor  70  on the rotary tool  72 , and also place the quick release attachment adaptor  100  on the attachment tool  102  to use the quick release attachment system. 
     From the foregoing it should be appreciated that an improved quick release attachment system has been shown and described which has many desirable advantages and attributes. The system provides a quick engage/disengage feature that is user friendly, and prevents rotation of the accessory attachment relative to the tool body during use. 
     While a particular embodiment of the quick release attachment tool has been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims. 
     Various features of the invention are set forth in the appended claims.