Positive drive chuck and bur arrangement for a dental handpiece

Abstract

A chuck assembly for a dental handpiece includes a hollow cylindrical tube portion having a first internal bore, and a chuck portion having a second bore. The chuck portion is supported within the first bore co-rotational with the tube portion about a common axis. The chuck portion has an annular body portion defining the second bore for supporting a cylindrical tool therein. A drive element comprising a drive pin inserted in a first end of the tube portion traverses the first internal bore at a first end of the tube portion. The drive pin cooperates with a distal end of a rotary tool insertable into the second bore to transfer torque to the tool. The tool has an elongated body portion having a driven portion and a working portion. The driven portion includes a shank portion with channels for receiving the drive pin.

1 . A rotatable 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 a drive element of a dental handpiece drive.   
     
     
         2 . The dental bur of  claim 1 , further comprising a circumferential groove disposed in the shank portion, intermediate the distal end and the working portion; the circumferential groove configured to receive a detent of a chuck in a dental handpiece for axial positioning and retention within the handpiece. 
     
     
         3 . The dental bur of  claim 1 , wherein the dental bur is removably insertable within an internal bore of a bur tube, the bur tube rotatably mounted in a drive head of a dental handpiece. 
     
     
         4 . The dental bur of  claim 1 , wherein the working portion further comprises a transition portion and a tool portion, the transition portion disposed between the shank portion and the tool portion. 
     
     
         5 . The dental bur of  claim 4 , wherein the transition portion connects the tool portion to the driven portion, the transition portion tapering outwardly from the tool portion to the driven portion. 
     
     
         6 . The dental bur of  claim 3 , wherein the drive element comprises a drive pin, the drive pin configured to transfer rotational torque from the bur tube. 
     
     
         7 . The dental bur of  claim 3 , wherein torque is transferred from the bur tube by the drive element engaging at least one opposing wall of the at least one channel. 
     
     
         8 . The dental bur of  claim 3 , wherein torque is transferred from the bur tube when rotating by the drive element engaging at least one post of four posts, the four posts defined by a pair of intersecting channels. 
     
     
         9 . The dental bur of  claim 8 , wherein the intersecting channels traverse the distal end of shank portion, the pair of channels intersecting generally perpendicularly. 
     
     
         10 . The dental bur of  claim 2 , wherein the circumferential groove is configured to receive at least one detent in the bur tube, for radially positioning and retaining the dental bur. 
     
     
         11 . The dental bur of  claim 1 , wherein the shank portion is generally cylindrical and insertable into the drive head of the dental handpiece. 
     
     
         12 . 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 therein; and   a drive element comprising a drive pin inserted in a first end of the tube portion traversing the first internal bore at a first end of the tube portion, the drive pin cooperative with a distal end of a rotary tool insertable into the second internal bore to impart torque to the tool.   
     
     
         13 . The dental bur of  claim 12 , wherein the annular body portion further comprises a ring portion and plurality of elongated 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; and flexible for gripping a tool when a tool is inserted axially in the second internal bore. 
     
     
         14 . The dental bur of  claim 13 , wherein each spring of the plurality of elongated springs further comprises a detent projecting radially inward to engage a channel in the tool to axially position and retain the tool within the chuck portion. 
     
     
         15 . The dental bur of  claim 14 , 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 the spring portions towards the internal surface of the tube portion a sufficient amount to release the tool from the second internal bore. 
     
     
         16 . The dental bur of  claim 15 , 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 spring portions and movable within the first bore, wherein when the wedge portion is axially advanced between the spring portions the detents disengage with the channel and release the tool. 
     
     
         17 . The dental bur of  claim 16 , wherein the chuck assembly further comprises a pushbutton assembly adjacent the release portion for applying an axial force on the wedge portion. 
     
     
         18 . The dental bur of  claim 17 , wherein the pushbutton has a return spring to urge the pushbutton away from the release portion. 
     
     
         19 . 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 therein; and   a drive element comprising a drive pin inserted in a first end of the tube portion traversing the first internal bore at a first end of the tube portion, the drive pin cooperative with a distal end of a rotary tool insertable into the second internal bore to impart torque to the tool.   
     
     
         20 . The dental handpiece of  claim 19 , the tool further 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 a drive element of a dental handpiece drive.