Brushhead assembly for a power toothbrush

Abstract

A brushhead assembly for use with a power toothbrush, comprising a toothbrush element ( 18 ), a mounting neck ( 22 ) on which the toothbrush element is mounted and a coupling member ( 24 ) which mates a driveshaft (from a drive system in a handle assembly portion ( 12 ) of the toothbrush to the mounting neck. A ring member ( 34 ) is positioned within a groove ( 30 ) at the proximal end ( 32 ) of the coupling member to create a desired brushhead assembly inertia. On an extending portion of the coupling member is mounted a spring member ( 28 ) which is configured and arranged and has such a spring rate that when the coupling member and mounting neck are installed into a driveshaft, a preload force is created between the brushhead assembly and the driveshaft sufficient to react the torque created by the rotating inertia movement of the brushhead assembly, without lost motion or noise.

1 . A brushhead assembly for use with a power toothbrush which includes a handle assembly to which the brushhead assembly is mounted, comprising:
 a toothbrush member ( 18 );   a mounting neck member ( 22 ) on which the toothbrush member is mounted;   a coupling member ( 24 ) which mates a motor driveshaft ( 14 ) from a handle assembly portion ( 12 ) of the toothbrush to the mounting neck member; and   an inertia member assembly ( 34 ) associated with the coupling member for producing a pre-selected inertia ratio between the brushhead assembly and the handle assembly of the toothbrush.   
     
     
         2 . The brushhead assembly of  claim 1 , wherein the inertia member assembly is positioned so as to be symmetrical about a rotational axis of the toothbrush. 
     
     
         3 . The brushhead assembly of  claim 1 , wherein the inertia member assembly is positionable within the coupling member. 
     
     
         4 . The brushhead assembly of  claim 1 , wherein the inertia member is positionable on the outside of the coupling member. 
     
     
         5 . The brushhead assembly of  claim 1 , wherein the inertia assembly is a continuous ring. 
     
     
         6 . The brushhead assembly of  claim 1 , wherein the ring is metal. 
     
     
         7 . The brushhead assembly of  claim 5 , wherein the ring has a dimension which is greater than the other parts of the brushhead assembly. 
     
     
         8 . The brushhead assembly of  claim 5 , wherein the ring is a ceramic or plastic material. 
     
     
         9 . The brushhead assembly of  claim 1 , wherein the inertia assembly is positioned in a circumferential groove ( 30 ) at a proximal end ( 32 ) of the coupling member. 
     
     
         10 . The brushhead assembly of  claim 5 , wherein the friction force between the inertia ring and the coupling member is sufficient to prevent rotational slippage of the ring at torque values encountered during normal operation of the toothbrush. 
     
     
         11 . The system of  claim 9 , wherein the circumferential groove includes elements ( 74 ) tending to prevent axial and/or rotational movement of the ring during operation of the toothbrush. 
     
     
         12 . In a brushhead assembly for use in a power toothbrush which comprises a toothbrush member ( 18 ), a mounting neck element ( 22 ) on which the toothbrush member is mounted and a coupling member ( 24 ) which mates a motor driveshaft ( 14 ) from a motor drive assembly present in a handle assembly portion ( 12 ) of the power toothbrush to the mounting neck, the improvement comprising:
 a ring member ( 34 ) connected to the coupling member for tuning the inertia of the brushhead assembly relative to the inertia of the handle assembly portion of the toothbrush to a pre-selected ratio.   
     
     
         13 . The improvement of  claim 12 , wherein the ring member is positioned within a circumferential groove ( 30 ) in the coupling member so that it is symmetrical about the rotational axis of the toothbrush. 
     
     
         14 . The improvement of  claim 12 , wherein the ring member is metal, and, wherein the friction force between the ring member and the groove in the coupling member is such as to substantially prevent rotational slippage of the ring member at values of torque on the coupling member produced during operation of the toothbrush. 
     
     
         15 . A brushhead for use with a power toothbrush, comprising:
 a toothbrush member ( 18 );   a mounting neck ( 22 ) on which the toothbrush element is mounted;   a coupling member ( 24 ) which mates a driveshaft ( 14 ) from a motor drive assembly contained within a handle assembly portion ( 12 ) of the toothbrush to the mounting neck; and   a spring member ( 28 ) fitted on an extending portion of the coupling member, into which coupling member the driveshaft fits sufficiently tightly, with the force of the spring member, to transfer the oscillating action of the driveshaft to the mounting neck, and vice versa, as the brushhead member oscillates in response to action of the driveshaft.   
     
     
         16 . The brushhead assembly of  claim 15 , wherein the spring member is insertable onto and removable from the extending portion of the coupling member and wherein the spring member is configured and arranged structurally to produce a sufficiently tight fit between the spring member, coupling member and the driveshaft to react and/or transfer torque between the driveshaft and the brushhead assembly when the driveshaft is operatively inserted into the coupling member and the coupling member is operatively inserted into the mounting neck. 
     
     
         17 . The brushhead assembly of  claim 15 , wherein the spring member produces a preload which is sufficient to prevent relative movement between the brushhead member and the driveshaft while permitting convenient removal of the mounting neck and brush element from the driveshaft. 
     
     
         18 . The brushhead assembly of  claim 15 , wherein the spring member is an angular C shape which fits around the exterior surface of the coupling member. 
     
     
         19 . The brushhead assembly of  claim 15 , wherein the spring member is in the form of a closed oval, a closed circle, a coil spring or a leaf spring. 
     
     
         20 . In a brushhead assembly for use with a power toothbrush which comprises a toothbrush element ( 18 ), a mounting neck ( 22 ) on which the toothbrush element is mounted and a coupling member ( 24 ) which mates a driveshaft ( 14 ) from a motor drive assembly within a handle assembly portion ( 12 ) of the toothbrush to the mounting neck, the improvement comprising:
 a spring member ( 28 ) fittable onto an extending portion of the coupling member ( 24 ), into which coupling member the driveshaft fits sufficiently tightly, with the force produced by the spring member, that the coupling member follows the oscillating action of the driveshaft and reacts the torque from the resulting oscillating action of the brushhead assembly.   
     
     
         21 . In the brushhead assembly of  claim 20 , the spring member comprises a metal element, with a spring rate which prevents lost motion between the driveshaft and the mounting neck.