Abstract:
An elongated flexible power transmission cable couples an electric motor within a control unit with a dental handpiece. The handpiece has a rotatable tool used for performing dental work within a patient&#39;s mouth. The power transmission device comprises a generally flexible and elongated cover having a proximal attachment end, a distal attachment end and a longitudinal axis that extends between the proximal and distal attachment ends. The proximal attachment end is mountable to the control unit and the distal attachment end is mountable to the dental handpiece. A generally flexible and elongated driving cable is rotatably positioned within the cover. The driving cable is generally rotatable about the longitudinal axis and has a proximal end for coupling with the electric motor and a distal end for coupling with and driving the dental handpiece. The driving cable transmitting torque from the electric motor to the dental handpiece

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 60/942,518 filed Jun. 7, 2007 entitled “Flexible Power Transmission Cable for Driving a Dental Handpiece”. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to a power transmission device, specifically a power transmission device having a flexible power transmission cable for driving a dental handpiece. 
         [0003]    Dental practitioners use a variety of tools for dental treatments such as drilling, grinding, polishing, scaling and other periodontal treatments, root canal therapy and the like. A dental practitioner often uses a variety of tools for a single procedure. A drilling tool, a light source, chip air and water are often needed to perform a single procedure. Since a mouth is a small space in which to work and children or those suffering from trismus or an otherwise limited ability to open their mouth, it is often difficult to see well and operate equipment in all regions of the mouth. When a dental practitioner cannot see clearly in the field of work or reach a tooth or gum section at a particular angle, it is more likely that a painful slip can occur or the procedure is otherwise limited. Additionally, more than one hand and or person is needed to operate air, water, light and drilling devices simultaneously or seamlessly. 
         [0004]    Dental drills are typically pneumatically or electrically driven with the motor coupled directly to a removable handpiece. Pneumatic drills are useful in high speed configurations but are difficult to accurately control with a foot pedal and often do not provide sufficient torque. Electrically driven drills provide for increased control and torque but results in a larger and much heavier handpiece due to the use of an electric motor and corresponding components proximate the handpiece. The larger size and weight of the electrically driven handpiece hinders dexterity, tires the dental practitioner faster and obstructs the mouth opening and view of the practitioner. 
         [0005]    What is therefore needed is a dental tool that has a handpiece having characteristics of a pneumatic drill with the increased torque and precision speed of an electric motor. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    Briefly stated, the present invention is directed to an elongated flexible power transmission cable for coupling an electric motor within a control unit with a dental handpiece. The handpiece has a rotatable tool used for performing dental work within a patient&#39;s mouth. The power transmission device comprises a generally flexible and elongated cover having a proximal attachment end, a distal attachment end and a longitudinal axis that extends between the proximal and distal attachment ends. The proximal attachment end is mountable to the control unit and the distal attachment end is mountable to the dental handpiece. A generally flexible and elongated driving cable is rotatably positioned within the cover. The driving cable is generally rotatable about the longitudinal axis and has a proximal end for coupling with the electric motor and a distal end for coupling with and driving the dental handpiece. The driving cable transmits torque from the electric motor to the dental handpiece 
         [0007]    In another aspect, the invention is directed to a power transmission device for driving a dental handpiece that has a rotatable tool for performing dental work within a patient&#39;s mouth. The power transmission device comprises a control unit housing an electric motor and a flexible power transmission cable. The flexible power transmission cable includes a generally flexible and elongated cover that has a proximal attachment end, a distal attachment end and a longitudinal axis that extends between the proximal and distal attachment ends. The proximal attachment end is mounted to the control unit and the distal attachment end is mountable to the dental handpiece. A generally flexible and elongated driving cable rotatably positioned within the cover. The driving cable is generally rotatable about the longitudinal axis and has a proximal end coupled with the electric motor and a distal end for coupling with and driving the dental handpiece such that torque is transmitted from the electric motor to the dental handpiece. 
         [0008]    In another aspect, the invention is directed to a power transmission device for driving a dental handpiece that has a rotatable tool for performing dental work within a patient&#39;s mouth. The power transmission device comprises a control unit that houses an electric motor. The control unit has a display screen and at least one control button. A flexible power transmission cable includes a generally flexible and elongated cover that has a proximal attachment end, a distal attachment end and a longitudinal axis extending between the proximal and distal attachment ends. The proximal attachment end has a threaded collar that is removably mounted to the control unit and the distal attachment end is removably mountable to the dental handpiece. A generally flexible and elongated driving cable is rotatably positioned within the cover. The driving cable is generally rotatable about the longitudinal axis and has a proximal end coupled with the electric motor and a distal end coupled with and driving the dental handpiece such that torque is transmitted from the electric motor to the dental handpiece. A water line extends from the control unit through the flexible power transmission cable to the dental handpiece. An air line extends from the control unit through the flexible power transmission cable. A delivery system connected to the control unit delivers air and water to the air and water lines respectively. A foot pedal that controls the speed of the electric motor is connected to the delivery system. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0009]    The foregoing summary, as well as the following detailed description of a preferred embodiment of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings an embodiment which is presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. 
           [0010]    In the drawings: 
           [0011]      FIG. 1  is a perspective view of a power transmissions device having a control unit and flexible power transmission cable in accordance with a preferred embodiment of the present invention connected to a dental handpiece and schematically connected to a delivery system and foot pedal; 
           [0012]      FIG. 2  is a left side elevational view of the flexible power transmission cable shown in  FIG. 1 ; 
           [0013]      FIG. 3  is a cross sectional view, partially broken, of the cable shown in  FIG. 2  taken along line  3 - 3  in  FIG. 2 ; 
           [0014]      FIG. 4  is a left side elevational view of a handpiece coupler shown in  FIG. 1 ; 
           [0015]      FIG. 5  is a right side elevational view of the flexible power transmission cable shown in  FIG. 1 ; and 
           [0016]      FIG. 6  is a cross sectional view of the handpiece coupler shown in  FIG. 5  taken along line  6 - 6  of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    Certain terminology is used in the following description for convenience only and is not limiting. The words “right”, “left”, “lower” and “upper” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of a power transmission device for driving a dental handpiece in accordance with the present invention, and designated parts thereof. Unless specifically set forth herein, the terms “a”, “an” and “the” are not limited to one element but instead should be read as meaning “at least one”. The terminology includes the words noted above, derivatives thereof and words of similar import. 
         [0018]    Referring to the drawings, wherein like numerals indicate like elements throughout, there is shown in  FIGS. 1-6  a power transmission device, generally designated  10 , for driving a dental handpiece (handpiece)  12 . The power transmission device  10  includes a flexible power transmission cable  14  that couples a control unit  16  to a detachable drill or other handpiece  12 . The handpiece  12  is similar to those known in the art that are removably latched or coupled to the driving end of a pneumatic or electric motor. The handpiece  12  is for performing dental work on a tooth or related area as discussed in further detail below. 
         [0019]    The control unit  16  houses electrical components and an electric motor  18  for powering and driving the handpiece  12 . The control unit  16  includes a plurality of inlet ports, partially shown at  26 , for supplying water and air for use in the handpiece  12 . The control unit  16  is operatively connected to a delivery system  20  (shown schematically) proximate a dental chair (not shown) and a foot pedal  22  (shown schematically) that is connected to the delivery system  20 . The foot pedal  22  controls the speed of the electric motor  18 . The foot pedal  22  is placed on the floor proximate the dental chair to allow the dental practitioner to control the speed of the handpiece  12  with his or her foot. The control unit  16  preferably includes a display screen  28 . The display screen  28  is preferably an LCD or similar electronic screen for displaying settings and operating conditions of the control unit  16 . The control unit  16  also preferably includes at least one control button or switch  30  for controlling various settings of the control unit  16 . Alternatively, the control buttons  30  may be positioned remotely from the control unit  16  such as on the dental chair, the delivery system  20 , the foot pedal  22  or on the flexible power transmission cable  14  proximate to the handpiece  12 . The speed of the electric motor  18  may be displayed on the display screen  28 . The control buttons  30  allow a user to set torque and speed limits of the flexible power transmission cable  14 . Other settings include but are not limited to turning on a light  66  (described further below), setting auto-reverse on, programming what specific attachment or handpiece  12  is being used and also various other pre-sets for the power transmission device  10 . The control unit  16  is preferably powered by a power supply  24 . However, the control unit  16  may alternatively be powered through the delivery system  20 . 
         [0020]    Referring to  FIGS. 1-3 , the flexible power transmission device  10  includes a proximal attachment end  32  and a distal attachment end  34 . A longitudinal axis  36  ( FIG. 3 ) extends between the proximal and distal attachment ends  32 ,  34 . The flexible power transmission cable  14  includes a driving cable  38  which is generally rotatable about the longitudinal axis  36 . The driving cable  38  is preferably a braided or winding type metallic cable but the driving cable  38  may be comprised of nearly any material and configuration such that the driving cable  38  has the thinnest cross section strong enough to withstand the torque needed to the drive the dental handpiece  12 . The driving cable  38  includes a keyed proximal end  38   a  that is sized and shaped to fit within or to be otherwise secured to the output shaft (not shown) of the electric motor  18 . Alternatively, the proximal end  38   a  may included a threaded collar (not shown) that is threadably attached to the output shaft of the electric motor  18 . The distal end of the driving cable  38  is attached to and drives an output shaft  44 . The driving cable  38  is preferably fixedly attached to the output shaft  44  (see  FIG. 6 ) but the driving cable  38  and the output shaft  44  may be integrally formed. 
         [0021]    The flexible power transmission device  10  includes a flexible and elongated cable covering or cover  40 . The cover  40  is a flexible outer covering to protect the driving cable  38  and air and water lines  42 . The cable covering  36  is preferably constructed of a polymeric material specifically a PEEK covering. However, the cable covering  36  may be constructed of any suitable material such as a wound metal covering to provide a flexible, lightweight and durable protective cover. The cover  40  is preferably mounted or attached to the driving cable  38  at the proximal and distal attachment ends  32 ,  34  of the flexible power transmission cable  14 . The cover  40  is preferably attached to the driving cable  38  by a ball bearing ring  68  or any suitable connector such that the driving cable  38  may rotate relative to the cover  40 . 
         [0022]    The proximal attachment end  32  of the flexible power transmission cable  14  is preferably removably mounted to the control unit  16  though the power transmission cable  14  may be fixedly attached to the control unit  16 . The proximal attachment end  32  of the flexible power transmission cable  14  preferably includes a threaded collar  46  that is rotatably mounted to the proximal attachment end  32  of the flexible power transmission cable  14  and threadingly attaches to the control unit  16 . The proximal attachment end  32  of the flexible power transmission cable  14  also preferably includes a backshell  48 . The collar  46  is rotatably mounted over the backshell  48 . Tightening the collar  48  in the appropriate direction draws the proximal attachment end  32  of the flexible power transmission cable  14  toward the control unit  16  and engages the driving cable  38  with the electric motor  18 . 
         [0023]    Referring to  FIGS. 2 ,  3  and  4 , the proximal attachment end  32  of the flexible power transmission cable  14  preferably includes at least one and preferably two spaced apart pins  50  for insertion within and electrical connection to the control unit  16 . The pins  50  are used to establish an electrical connection for any of the electrical components of the handpiece  12 . The proximal attachment end  32  also preferably includes a plurality of ports  42   a  for connecting to the air and water lines  42 . The ports  42   a  are preferably fluidly engaged with a corresponding plurality of air and water lines  42  within the control unit  16 . The ports  42   a  and corresponding air and water lines  42  are preferably arranged to at least provide an air port for cooling the light  66  and other components and a port  42   c  for providing chip water. The air and water lines  42  run along side of and are preferably radially outwardly spaced from the driving cable  38  and are preferably circumferentially spaced from each other within the cover  40 . 
         [0024]    Referring to  FIGS. 3 and 6 , the output shaft  44  is housed within a handpiece coupler  52  at the distal attachment end  34  of the flexible power transmission cable  14 . The output shaft  44  has a t-shaped distal end  44   a . The handpiece coupler  52  includes a coupler backshell  54  that preferably fixedly extends partially over the distal end of the cover  40 . A handpiece plug (plug)  56  extends from the distal end of the handpiece coupler  52  and preferably covers the output shaft  44  to protect users from the output shaft  44  when the handpiece  12  is removed. The handpiece  12  receives the plug  56  and snap fits into releasble engagement with the handpiece coupler  52 . A spring biased releasable catch  58  is preferably disposed within the handpiece coupler  52 . When the handpiece  12  is pulled away from the handpiece coupler  52  with a sufficient force, the catch  58  radially releases the handpiece  12  from the handpiece coupler  52 . An end cap  70  is preferably mounted to the distal end of the handpiece coupler  52  and held in place by a plurality of screws  72  ( FIG. 5 ). 
         [0025]    The distal end  44   a  of the output shaft  44  engages with a drive shaft  60  within the handpiece  12 . The drive shaft  60  drives a gear train  62  for powering a rotating tool such as a drill bit  64 . The water line  42  connects with the water line  42   c  in the handpiece  12 . The water is sprayed from a nozzle  68  in the handpiece  12  and is used to clear and cool the drill bit  64  and clear or clean the work area. The light bulb  66 , positioned toward the distal end of the handpiece coupler  52  emits light from the end of the nozzle  68  in the proximity of the drill bit  64  and the work area to enable a better view when working inside the mouth. The light from the light bulb  66  is brought through the handpiece  14  to the work area through a lumen  66   b . The light bulb  66  is connected to power wires  66   a  inside the cover  40  by crimped AMP or other connectors (not shown). 
         [0026]    It will be appreciated by those skilled in the art that changes could be made to the embodiment described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiment disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.