Dental device with load-responsive motor control

Patent metadata

Field	Value
Publication number	US-11857384-B2
Application number	US-202016907519-A
Country	US
Kind code	B2
Filing date	Jun 22, 2020
Priority date	Sep 7, 2016
Publication date	Jan 2, 2024
Grant date	Jan 2, 2024

Abstract

A motor-driven dental device has a motor control that is responsive to a load placed upon the motor. More specifically, the invention relates to a dental device having motor that drives a tool, wherein the tool is activated or otherwise controlled in response to a load placed upon the motor through the tool, such as by touching the tool to a surface. The tool may also be controlled by the sustenance, over a predetermined time period, of an increase or decrease in motor current beyond a predetermined hysteresis current threshold. The motor may be an electric motor, a rotary electric motor, and air driven motor, an ultrasonic device or the like.

First claim

The invention claimed is:

1. A method of controlling a motor driven dental handpiece having a motor control for driving a motor for dental treatment comprising:
applying a tool of the handpiece to a tooth to generate a load,
applying said load to an electric motor of the handpiece,
increasing or decreasing a speed of the tool of the handpiece to a controlled output goal corresponding to said load,
wherein the increasing or decreasing is according to a motor-control profile of the handpiece,
wherein during a period of application of the load to the electric motor, the speed is automatically increased for an increasing load and automatically decreased for a decreasing load without a use of a pedal, and
wherein the load is a torque applied to the electric motor.

2. The method according to claim 1 , further comprising, reducing the speed of the motor to an idle speed when the torque is low or no longer applied.

3. The method according to claim 2 , wherein the idle speed is 300 rpm and the torque is 0.5 ozf·in or below.

4. A system comprising a processor wherein the processor is configured to perform the method of claim 1 .

5. The method according to claim 1 , wherein prior to applying tool of the handpiece to the tooth to generate the load, the electric motor is turned on with an initial speed equal to an idle speed, the idle speed being a preset value,
wherein a no-load motor current corresponding to the idle speed is obtained as part of a startup calibration of the motor driven dental handpiece that zeroes out the motor current generated by a drive system friction of the motor driven dental handpiece, and
wherein responsive to applying the tool of the handpiece to the tooth to generate to the load, the increasing or decreasing of the speed in response to increasing or decreasing load respectively is performed automatically within a defined speed range.

6. A method of controlling a motor driven dental handpiece having a motor control for driving a motor for dental treatment comprising:
applying a tool of the handpiece to a tooth to generate a load,
applying said load to an electric motor of the handpiece,
increasing or decreasing a speed of the tool of the handpiece to a controlled output goal corresponding to said load,
wherein the increasing or decreasing is also according to a sustenance of a new motor current resulting from a change in a motor current above a predetermined hysteresis current threshold, over a predetermined time period, and
wherein during a period of application of the load to the electric motor, the speed is automatically increased for an increasing load and automatically decreased for a decreasing load without a use of a pedal.

7. The method according to claim 6 , wherein the load is a torque applied to the motor.

8. The method according to claim 7 , further comprising selecting a new speed based on a new motor current operating point if said change in the motor current is greater than the predetermined hysteresis current threshold.

9. The method according to claim 7 , further comprising, reducing the speed of the motor to an idle speed when the torque is low or no longer applied.

10. The method according to claim 7 , further comprising, observing a maximum preset speed of the motor beyond which said speed cannot increase.

11. The method according to claim 7 , further comprising, overriding the motor control through wireless radio communication.

12. The method according to claim 7 , further comprising, controlling the motor speed by a combination of a plurality or predetermined or variable time periods and hysteresis current thresholds.

13. The method according to claim 7 , further comprising, maintaining the speed within 300 amp and 3200 rpm as the torque varies between 0.5 ozf-in to 1.3 ozf-in.

14. The method according to claim 7 , wherein the increase or decrease can be in as few as two steps, on/off, or in many steps, or in a constant or variable proportional to the torque.

15. The method according to claim 8 , further comprising,
determining and updating an upper hysteresis limit current and a lower hysteresis limit current based on said predetermined hysteresis current threshold, wherein if the new motor current operating point is greater than the upper hysteresis limit current or lower than the lower hysteresis limit current, a new upper hysteresis limit current and lower hysteresis limit current are set.

16. The method according to claim 6 , wherein prior to applying tool of the handpiece to the tooth to generate the load, the electric motor is turned on with an initial speed equal to an idle speed, the idle speed being a preset value,
wherein a no-load motor current corresponding to the idle speed is obtained as part of a startup calibration of the motor driven dental handpiece that zeroes out the motor current generated by a drive system friction of the motor driven dental handpiece, and
wherein responsive to applying the tool of the handpiece to the tooth to generate to load, the increasing or decreasing of the speed in response to increasing or decreasing load respectively is performed automatically within a defined speed range.

Assignees

• Dentsply Sirona Inc

Inventors

• Fayer Jay Alexander
• Michel Ignacio
• Reagan Joseph R
• Lint Kevin
• Kile Jeremy
• Beane Bret

Classifications

• A61C1/003 Primary

  Control of rotation of instrument · CPC title

• A61C1/0038

  Pneumatic systems · CPC title

• A61C1/186

  with torque adjusting or limiting means · CPC title

• H02P29/0016

  Control of angular speed of one shaft without controlling the prime mover · CPC title

• A61C17/005

  Devices for dental prophylaxis · CPC title