Abstract: A backlash-free planetary gear assembly comprising at least a first planet carrier member (4) and a second planet carrier member (5), which are rotatable relative to each other around the axis (7) of said assembly, and are connected by elastic means (10, 14) arranged to elastically react to a rotation between said planet carrier members, said elastic means being tensioned when said first member and second member are rotationally aligned in a design operation condition, so that the assembly, in use, is preloaded with a torque which tends to rotate said first planet carrier member relative to said second planet carrier member, in order to recover backlash.

Abstract: A backlash-free planetary gear assembly comprising at least a first planet carrier member (4) and a second planet carrier member (5), which are rotatable relative to each other around the axis (7) of said assembly, and are connected by elastic means (10, 14) arranged to elastically react to a rotation between said planet carrier members, said elastic means being tensioned when said first member and second member are rotationally aligned in a design operation condition, so that the assembly, in use, is preloaded with a torque which tends to rotate said first planet carrier member relative to said second planet carrier member, in order to recover backlash.

Abstract: The present invention relates to a handheld dental instrument having a movable tip portion including one end rotatably secured to a distal end of a handle portion and an opposing end defining a tip including a tip member adapted for intra oral use whereby the tip can be rotated and fixedly positioned at various locations about an axis. The tip member and/or tip portion optionally may be removable.