Positive drive chuck and bur arrangement for a dental handpiece

1. A chuck assembly for a dental handpiece, the chuck assembly comprising:

a hollow cylindrical tube portion having a first internal bore, and a chuck portion having a second internal bore,

the chuck portion supported within the first internal bore and co-rotational with the tube portion about a common axis;

the chuck portion comprising an annular body portion defining the second internal bore, for retentively supporting a cylindrical tool capable of being inserted therein but not preventing rotational slippage of the tool about the axis, the annular body portion further comprising a ring portion and a plurality of flexible, elongate springs, the springs separated by slots, the springs extending longitudinally from the ring portion and parallel with the axis, the springs tapering radially inwardly away from an internal surface of the tube portion towards the axis to provide flexibility to deflect outwardly, the plurality of elongate springs further comprising a detent projecting radially inward capable of engaging a shoulder in the tool to axially position and retain the tool within the chuck portion when received therein; and

a drive element comprising a drive pin inserted in a first end of the tube portion traversing the first internal bore at the first end of the tube portion, the drive pin cooperative with at least one channel disposed at a distal end of the tool capable of being inserted into the second internal bore to impart torque to the tool when inserted therein;

wherein the detent and the drive pin are capable of engaging the shoulder and the at least one channel, respectively, to axially position and retain the tool within the chuck portion when received therein.

2. The chuck assembly of claim 1 , wherein the chuck assembly further includes a release portion disposed within the first internal bore adjacent the chuck portion, the release portion engageable with the chuck portion to displace distal ends of the elongate springs radially outward toward the internal surface of the tube portion a sufficient amount capable of releasing the tool from the second internal bore.

3. The chuck assembly of claim 2 , wherein the release portion comprises a wedge portion comprising an aperture for the drive pin to pass through, the wedge portion having a tapered member positioned adjacent the springs and movable within the first bore, wherein when the wedge portion is axially advanced between the springs, the detents capable of disengaging with the channel to release the tool when the tool is present in the second internal bore.

4. The chuck assembly of claim 1 , the tool further comprising a rotatable dental bur, the dental bur comprising:

an elongated body portion having a driven portion and a working portion;

the driven portion including a shank portion having at least one channel disposed at a distal end for receiving the drive element of a dental handpiece drive.

5. A dental handpiece comprising a handle, a tool-supporting drive head, a swivel connector for connecting the handpiece to a supply of air, water or electricity, the drive head comprising:

a chuck assembly for a dental handpiece, the chuck comprising:

a hollow cylindrical tube portion having a first internal bore, and a chuck portion having a second internal bore,

the chuck portion supported within the first internal bore and co-rotational with the tube portion about a common axis;

the chuck portion comprising an annular body portion defining the second internal bore, for retentively supporting a cylindrical tool capable of being inserted therein but not preventing rotational slippage of the tool about the axis, the annular body portion further comprising a ring portion and a plurality of flexible, elongate springs, the springs separated by slots, the springs extending longitudinally from the ring portion and parallel with the axis, the springs tapering radially inwardly away from an internal surface of the tube portion towards the axis to provide flexibility to deflect outwardly, the plurality of elongate springs further comprising a detent projecting radially inward capable of engaging a shoulder in the tool to axially position and retain the tool within the chuck portion when received therein; and

a drive element comprising a drive pin inserted in a first end of the tube portion traversing the first internal bore at the first end of the tube portion, the drive pin cooperative with at least one channel disposed at a distal end of the tool insertable into the second internal bore to impart torque to the tool;

wherein the detent and the drive element are capable of engaging the shoulder and the at least one channel, respectively, to axially position and retain the tool within the chuck portion when received therein.

6. The dental handpiece of claim 5 , the tool further comprising a rotatable dental bur, the dental bur comprising:

an elongated body portion having a driven portion and a working portion;

the driven portion including a shank portion having at least one channel disposed at a distal end for receiving the drive element of a dental handpiece drive.

7. The dental handpiece of claim 5 , wherein the chuck assembly further includes a release portion disposed within the first internal bore adjacent the chuck portion, the release portion engageable with the chuck portion to displace distal ends of the elongate springs radially outward towards the internal surface of the tube portion a sufficient amount capable of releasing the tool from the second internal bore.

8. The dental handpiece of claim 7 , wherein the release portion comprises a wedge portion comprising an aperture for the drive pin to pass through, the wedge portion having a tapered member positioned adjacent the springs and movable within the first bore, to axially advance the wedge portion between the springs such that the detents disengage with the channel and release the tool when the tool is present in the second internal bore.

9. The dental handpiece of claim 8 , wherein the dental handpiece further comprises a push button assembly adjacent the release portion for applying an axial force on the wedge portion.

10. The dental handpiece of claim 9 , wherein the push button assembly has a return spring to urge a push button away from a release position.