Dental burr and dental handpiece

A dental handpiece for rotatably holding a dental burr, said dental burr including an elongated burr body having a front and a rear end and having an axis of rotation therethrough in a direction of a length thereof, said body having a shank portion defined by a rear end portion thereof and a cutting portion defined by a front end portion thereof, said body having a first cooling water passage extending along the axis of said body, and said passage opening at one end to the rear end of said body and opening at the other end of an outer surface of said cutting portion of said body;

• said handpiece comprising:
• (a) a handpiece body including a handgrip portion and a head portion provided at one end of said handgrip portion and having an internal space therein, said head portion comprising a tubular portion formed at the one end of said handgrip portion and having opposite open ends through one of which said cutting portion of said dental burr is adapted to extend outwardly of said handpiece body, said head portion also comprising closure means for closing the other open end of said tubular portion, said handpiece body having a second cooing water passage comprising a first sub-passage and a second sub-passage, said first sub-passage being formed in said handgrip portion and connectable to a source of cooling water, said second sub-passage being formed in said tubular portion and closure means of said head portion, said second sub-passage having a proximal end connected to said first sub-passage and a distal end opening to an inner face of said closure means;
• (b) support means mounted within said internal space of said head portion for supporting said shank portion of said dental burr in such a manner that said cutting portion of said dental burr extends outwardly from said head portion, the distal end of said second sub-passage being communicated with said first cooling water passage when said dental burr is supported by said support means;
• (c) bearing means for rotatably supporting said support means in such a manner that said burr body is rotatable about the axis of rotation thereof, said support means being disposed in spaced relation to an inner surface of said head portion defining said internal space;
• and
• (d) drive means for imparting a rotational movement to said support means;
• wherein said support means includes a tubular rotatable portion disposed in facing relation to said inner surface of said closure means, said closure means having a projection formed an said inner surface thereof and extending therefrom into said tubular rotatable portion, said projection being disposed in coaxial relation to said first cooling water passage of said dental burr when said dental burr is supported by said support means, and said second sub-passage of said second cooling water passage having a distal portion extending through said projection along the axis of said projection;
• and
• wherein pump means is provided between an inner peripheral surface of said tubular rotatable portion of said support means and an outer peripheral surface of said projection of said closure means, said pump means achieving its pumping action by rotation of said tubular rotatable portion relative to said projection so that the cooling water disposed between the inner peripheral surface of said tubular rotatable portion and the outer peripheral surface of said projection is drawn by positive pressure toward said first cooling water passage of said cental burr.

A dental handpiece for rotatably holding a dental burr, said dental burr including an elongated burr body having a front and a rear end and having an axis of rotation therethrough in a direction of a length thereof, said body having a shank portion defined by a rear end portion thereof and a cutting portion defined by a front end portion thereof, said body having a first cooling water passage extending along the axis of said body, and said passage opening at one end to the rear end of said body and opening at the other end of an outer surface of said cutting portion of said body;

• said handpiece comprising:
• (a) a handpiece body including a handgrip portion and a head portion provided at one end of said handgrip portion and having an internal space therein, said head portion comprising a tubular portion formed at the one end of said handgrip portion and having opposite open ends through one of which said cutting portion of said dental burr is adapted to extend outwardly of said handpiece body, said head portion also comprising closure means for closing the other open end of said tubular portion, said handpiece body having a second cooling water passage comprising a first sub-passage and a second sub-passage, said first sub-passage being formed in said handgrip portion and connectable to a source of cooling water, said second sub-passage being formed in said tubular portion and closure means of said head portion, said second sub-passage having a proximal end connected to said first sub-passage and a distal end opening to an inner face of said closure means.
• (b) support means mounted within said internal space of said head portion for supporting said shank portion of said dental burr in such a manner that said cutting portion of said dental burr extends outwardly from said head portion, the distal end of said second sub-passage being communicated with said first cooling water passage when said dental burr is supported by said support means;
• (c) bearing means for rotatably supporting said support means in such a manner that said burr body is rotatable about the axis of rotation thereof, said support means being disposed in spaced relation to an inner surface of said head portion defining said internal space;
• and
• (d) drive means for imparting a rotational movement to said support means;
• wherein said support means includes a tubular rotatable portion disposed in facing relation to said inner surface of said closure means, said closure means having a projection formed an said inner surface thereof and extending therefrom into said tubular rotatable portion, said projection being disposed in coaxial relation to said first cooling water passage of said dental burr when said dental burr is supported by said support means, and said second sub-passage of said second cooling water passage having a distal portion extending through said projection along the axis of said projection;
• wherein said pump means is provided between an inner peripheral surface of said tubular rotatable portion of said support means and an outer peripheral surface of said projection of said closure means so that the cooling water disposed between the inner peripheral surface of said tubular rotatable portion and the outer peripheral surface of said projection is drawn by positive pressure toward said first cooling water passage of said cental burr by said pump means when said tubular rotatable portion is rotated;
• and
• wherein said closure means comprises a cap attached to the other open end of said tubular portion of said head portion and a push button mounted on said cap for movement relative said cap, said push button having a stem means slidably extending through said cap into said internal space and disposed in radially spaced relation to said projection;
• said support means comprising a tubular rotatable body supported by said bearing means so as to be rotatable about a longitudinal axis thereof extending along the axis of said tubular portion of said head portion, said support means also comprising chuck means received in said rotatable body so as to releasably chuck said shank portion of said dental burr;
• and said stem of said push button being operatively engageable with said chuck means so as to release the chucking of said shank portion by said chuck means when said push button is depressed.

A dental handpiece for rotatably holding a dental burr, said dental burr including an elongated burr body having a front and a rear end and having an axis of rotation therethrough in a direction of a length thereof, said body having a shank portion defined by a rear end portion thereof and a cutting portion defined by a front end portion thereof, said body having a first cooling water passage extending along the axis of said body, said passage opening at one end to the rear end of said body and opening at the other end to an outer surface of said cutting portion of said body;

• said handpiece comprising:
• (a) a handpiece body including a handgrip portion and a head portion provided at one end of said handgrip portion and having an internal space therein, said head portion comprising a tubular portion formed at the one end of said handgrip portion and having opposite open ends through one of which said cutting portion of said dental burr is adapted to extend outwardly of said handpiece body, said head portion also comprising closure means for closing the other open end of said tubular portion, said handpiece body having a second cooling water passage comprising a first sub-passage and a second sub-passage, said first sub-passage being formed in said handgrip portion and connectable to a source of cooling water, said second sub-passage being formed in said tubular portion and closure means of said head portion, said second sub-passage having a proximal end connected to said first sub-passage and a distal end opening to an inner face of said closure means;
• (b) support means mounted within said internal space of said head portion for supporting said shank portion of said dental burr in such a manner that said cutting portion of said dental burr extends outwardly from said head portion, the distal end of said second sub-passage being communicated with said first cooling water passage when said dental burr is supported by said support means;
• (c) bearing means for rotatably supporting said support means in such a manner that said burr body is rotatable about the axis of rotation thereof, said support means being disposed in spaced relation to an inner surface of said head portion defining said internal space;
• and
• (d) drive means for imparting a rotational movement to said support means;
• in which said bearing means comprises a pair of first and second bearing members spaced from each other along the axis of said tubular portion and disposed coaxially with said tubular portion said second bearing member being disposed at said one end of said tubular portion, said first bearing member being disposed between said closure means and said one end of said tubular portion so that said first bearing member cooperates with said support means to divide said internal space along the axis of said tubular portion into a first chamber closure to said closure means and a second chamber remote from said closure means, there being provided a plurality of blades fixedly mounted around said support means and disposed within said second chamber, said handpiece body having an air supply passage for supplying compressed air to said second chamber so that the compressed air acts on said blades to rotate said support means, said handpiece body also having an air discharge passage for discharging the compressed air from said second chamber, and said drive means comprising said blades and said air supply and discharge passages;
• and
• in which said air supply passage and said air discharge passage extend in a longitudinal direction of said handgrip portion toward a proximal end of said handgrip portion, said handpiece body having a communicating passage formed therein and communicating said first chamber of said internal space with said air discharge passage, said projection of said closure means being received in said tubular rotatable portion in closely spaced relation thereto, whereby the cooling water, leaking from said tubular rotatable portion into said first chamber through a space between said tubular rotatable portion and said projection, flows into said air discharge passage through said communicating passage to be discharged exteriorly of said handpiece body.