Cordless, battery operated surical tool

• US 5,747,953 A
• Filed: 03/29/1996
• Issued: 05/05/1998
• Est. Priority Date: 03/29/1996
• Status: Expired due to Term

• Current Assignee: Stryker Corporation
• Original Assignee: Stryker Corporation
• Inventors: Philipp, Chris
• Primary Examiner(s): Masih, Karen
• Application Number:
  US08/626,252
• Time in Patent Office: 767 Days
• Field of Search: 388/907, 388/937, 388/931, 318/139, 318/114, 318/119, 318/280, 318/686
• US Class Current: 318/139
• CPC Class Codes: A61B 17/1626 Control means; Display units
• CPC Class Codes: A61B 2017/00367 Details of actuation of instruments, e.g. relations between pushing buttons, or the like, and activation of the tool, working tip, or the like
• CPC Class Codes: A61B 2017/00734 battery operated
• CPC Class Codes: H01H 2300/014 Application surgical instrument
• CPC Class Codes: H01H 9/06 Casing of switch constituted by a handle serving a purpose other than the actuation of the switch, e.g. by the handle of a vacuum cleaner
• CPC Class Codes: H02P 25/032 Reciprocating, oscillating or vibrating motors
• CPC Class Codes: H02P 3/06 for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter
• CPC Class Codes: H02P 7/03 for controlling the direction of rotation of DC motors
• CPC Class Codes: H03K 17/97 using a magnetic movable element
• CPC Class Codes: Y10S 388/907 Specific control circuit element or device
• CPC Class Codes: Y10S 388/931 Electric generator or magnet as auxiliary load
• CPC Class Codes: Y10S 388/937 Hand tool

Abstract

A powered surgical tool includes a motor, a motor control module for controlling the actuation of the motor, and a trigger assembly for allowing the user to enter user-selected commands indicative of desired motor rotation. The trigger assembly includes a number of moving magnets located adjacent the sealed housing that contains the circuitry forming the motor control module. There are a set of magnetic field sensors in the motor control module housing. As the magnets are displaced in response to the user'"'"'s actuation of the switches, the sensors generate signals representative of the user-selected motor commands. The motor control module further includes a motor control circuit and a direction controller circuit that allow the motor to be driven in either forward, reverse or oscillatory rotation. When the motor is driven the oscillatory rotation, the direction control circuit and the motor control circuit cooperate to ensure the periodic reversal of the motor does not generate significant mechanical vibrations.

Claims

1. A powered surgical tool including:

a tool housing;

a motor disposed in said tool housing, said motor being actuatable in response to an application of energization signals thereto;

a motor control module disposed in said tool housing and connected to said motor, said motor control module having a motor control module housing that is fully enclosed and a motor control circuit contained in said motor control module housing, said motor control circuit being configured to supply the energization signals to said motor in response to at least a first motor command signal; and

a switch assembly attached to said tool housing adjacent said module control module housing, said switch assembly including;

a first actuatable switch that extends outside of said tool housing;

a first magnet attached to said first switch and disposed inside of said tool housing adjacent said motor control module housing and configured to move with the displacement of said first switch; and

a first magnetic field sensor disposed in said motor control module housing and positioned adjacent said first magnet, said first magnetic field sensor being configured to generate said first motor command signal to said motor control circuit based on movement of said first magnet.

2. The powered surgical tool of claim 1, wherein:

said switch assembly includes;

a second actuatable switch that extends outside of said tool housing;

a second magnet attached to said second switch and disposed in said tool housing adjacent said motor control module positioned and configured to move with the displacement of said second switch;

a third magnet movably secured inside said tool housing, said third magnet being positioned to be moved as a result of movement of either said first magnet or said second magnet;

a second magnetic field sensor disposed in said motor control module housing and positioned adjacent said second magnet, said second magnetic field sensor being configured to generate a second motor command signal to said motor control circuit based on movement of said second magnet; and

a third magnetic field sensor disposed in said motor control module housing and positioned adjacent said third magnet, said third magnetic field sensor being configured to generate a third motor command signal to said motor control circuit based on movement of said third magnet; and

said motor control circuit is configured to receive said first, second and third motor command signals and to supply energization signals to said motor based on said first, second and third motor command signals.

3. The powered surgical tool of claim 2, wherein said motor control circuit is configured so that:

when said first motor command signal and said third motor command signal are received as a result of the actuation of said first switch without the actuation of said second switch, said motor control circuit causes energization signals to be applied to said motor to cause said motor to rotate in a first direction;

when said second motor command signal and said third motor command signal are received as a result of the actuation of said second switch without the actuation of said first switch, said motor control circuit causes energization signals to be applied to said motor to cause said motor to rotate in a second direction opposite said first direction; and

when said first, second and third motor command signals are received as a result of simultaneous actuation of said first and second switches, said motor control circuit causes energization signals to be applied to said motor to cause said motor to undergo oscillatory rotation.

4. The powered surgical tool of claim 1, wherein said motor control module housing is formed with a plate and said motor control module housing plate is located adjacent said switch assembly first magnet and is formed with a cutout adjacent said switch assembly first magnet;

said first magnetic field sensor is located in said cutout; and

a seal is fastened to said motor control module housing plate over said cutout.

5. The powered surgical tool of claim 4, wherein said motor control module housing seal is formed from material more magnetically permeable than said motor control module housing plate.

6. The powered surgical tool of claim 1, wherein:

said tool housing has a handgrip and a motor section located above said handgrip wherein said motor is located in said tool housing motor section; and

said first actuatable switch extends forward of said handgrip.

7. The powered surgical tool of claim 6 further including a battery disposed in said tool housing handgrip for supplying energization signals to said motor.

8. The powered surgical tool of claim 1, further including a battery disposed in said tool housing for supplying energization power to said motor.

9. A powered surgical tool including:

a motor configured to be rotated in a forward direction and in a reverse direction at variable speeds in response to the application of selected energization signals thereto;

a motor controller connected to said motor for applying energization signals thereto, said motor controller being configured to apply energization signals to said motor to cause said motor to rotate at a selected speed in response to the application of a USER-SPEED signal applied thereto and in a specific direction in response to the application of a FORWARD/REVERSE signal thereto, wherein when said FORWARD/REVERSE signal is in a FORWARD/REVERSE state, said motor controller causes said motor to rotate in the forward direction and when said FORWARD/REVERSE signal is in a FORWARD/REVERSE state, said motor controller causes said motor to rotate in the reverse direction;

a plurality of user-actatuated switches for generating direction signals representative of a user-selected direction for motor rotation and for generating user-selected speed signals representative of a user-selected motor speed, wherein said switches are configured so that a user can actuate said switches to indicate if said motor should undergo forward, reverse or oscillatory rotation and said direction signals will indicate if said motor should undergo forward, reverse or oscillatory rotation; and

a direction controller connected to said switches for receiving said direction signals and said user-selected speed signals and connected to said motor controller for generating said FORWARD/REVERSE signal and said USER-SPEED signal thereto, said direction controller being configured to generate said FORWARD/REVERSE signal and said USER-SPEED signal based on said direction signals and said user-selected speed signals, wherein when said direction signals indicate said motor is to be driven in oscillatory rotation, said direction controller cyclically transitions said FORWARD/REVERSE signal between the FORWARD/REVERSE signal state and the FORWARD/REVERSE signal state and with each said state transition of said FORWARD/REVERSE signal, said direction controller pulses said USER-SPEED signal to a zero-speed USER-SPEED signal so as to cause said motor controller to apply energization signals to said motor based on the zero-speed USER-SPEED signal.

10. The powered surgical tool of claim 9, further including:

a motor sensor attached to said motor and configured to generate a MOTOR-SPEED signal based on the speed of the motor; and

said motor controller receives said MOTOR-SPEED signal from said motor sensor and is configured to assert signals to said motor to cause braking of said motor when said USER-SPEED signal is less than said MOTOR-SPEED signal.

11. The powered surgical tool of claim 9, wherein when said motor is driven in oscillatory rotation and said direction controller forces said USER-SPEED signal to the zero-speed USER-SPEED signal, said motor controller inhibits the application of energization signals to said motor.

12. The powered surgical tool of claim 9, further including:

a tool housing for containing said motor, said motor controller, said direction controller and said switches, wherein said switches extend out of said housing; and

a battery contained in said tool housing for supplying energization signals to said motor.

13. The powered surgical tool of claim 9, further including:

a current sensor connected to said motor to monitor the current drawn by said motor, said current sensor being configured to generate an adjustable CUR+ signal representative of the current drawn by said motor wherein said CUR+ signal is based on a variable volts/amp ratio established by said current sensor in response to a received current sensor control signal; and

wherein;

said motor controller is connected to said current sensor for receiving said CUR+ signal and is further configured to apply energization signals to said motor based on the magnitude of said CUR+ signal; and

said direction controller is connected to said current sensor for supplying said current sensor control signal thereto and is further configured so that when said motor is driven in oscillatory rotation each time said FORWARD/REVERSE signal transitions, to assert said a current sensor control signal to said current sensor to cause said current sensor to momentarily generate said CUR+ signal based on a first, high volts/amp ratio and to then generate said CUR+ signal based on a second, low volts/amp ratio.

21. The powered surgical tool of claim 11, wherein said motor controller is further configured to assert signals to said motor to cause braking of said motor and, when said direction controller forces said USER-SPEED signal to the zero speed USER-SPEED signal, said motor controller asserts the signals to said motor to cause braking of said motor.

14. A powered surgical tool including:

a motor, said motor having a magnetized rotor and a plurality of windings that surround said motor, said windings being configured to be selectively connected to either a power source or ground so as to cause the energization of said windings;

a motor sensor connected to said motor for generating a MOTOR-SPEED signal representative of the speed of said motor;

a speed controller including a user-actuated speed switch for regulating the speed of said motor, said speed controller being configured to generate a USER-SPEED signal in response to an actuation of said speed switch that is representative of a user-selected speed for said motor;

a motor controller connected to said motor for selectively connecting said windings to the power source or ground, to said motor sensor for receiving said MOTOR-SPEED signal, to said speed controller for receiving said USER-SPEED signal, said motor controller being configured to;

connect said motor windings to the power source or ground in response to said MOTOR-SPEED signal and said USER-SPEED signal so as to actuate said motor rotor;

to connect said motor windings to the power source or ground to cause the deceleration of said rotor in response to a BRAKE-ENABLE signal; and

when said MOTOR-SPEED signal and said USER-SPEED signal indicate said motor rotor is exceeding the user-selected speed by a given amount, to assert a BRAKE-TRIGGER signal; and

a brake controller connected to said motor sensor for receiving said MOTOR-SPEED signal and to said motor controller for receiving said BRAKE-TRIGGER signal, said brake controller being configured to cyclically assert said BRAKE-ENABLE signal to said motor controller when said BRAKE-TRIGGER signal is asserted and said MOTOR-SPEED signal indicates said motor rotor is moving and after said MOTOR-SPEED signal indicates said motor rotor has stopped moving, to negate the assertion of said BRAKE-ENABLE signal regardless of the state of said BRAKE-TRIGGER signal.

15. The powered surgical tool of claim 14, wherein said brake controller is further connected to said motor controller to inhibit said motor controller from connecting said motor windings to the power source whenever said BRAKE-TRIGGER signal is asserted.

16. The powered surgical tool of claim 14, further including:

a tool housing for containing said motor, said motor controller, said speed controller and said brake controller, wherein said speed controller user-actuated switch extends out of said housing; and

a battery contained in said tool housing for supplying energization signals to said motor.

17. A powered surgical tool including:

a motor, said motor having a magnetized rotor and a plurality of windings that surround said motor, said windings being configured to be selectively connected to either a power source or ground so as to cause the energization of said windings;

a motor sensor connected to said motor for generating a MOTOR-SPEED signal representative of the speed of said motor;

a speed controller including a user-actuated speed switch for regulating the speed of said motor, said speed controller being configured to generate a USER-SPEED signal in response to an actuation of said speed switch that is representative of a user-selected speed for said motor;

a motor controller connected to said motor for selectively connecting said windings to the power source or ground, to said motor sensor for receiving said MOTOR-SPEED signal, to said speed controller for receiving said USER-SPEED signal, said motor controller being configured to;

connect said motor windings to the power source or said ground in response to said MOTOR-SPEED signal and said USER-SPEED signal so as to actuate said motor rotor;

to connect said motor windings to the power source or ground to cause the deceleration of said rotor in response to a BRAKE-ENABLE signal;

amplify any difference between said USER-SPEED signal and said MOTOR-SPEED signal to produce an ERROR signal; and

compare said ERROR signal to a fixed signal and when said comparison indicates that said MOTOR-SPEED signal exceeds said USER-SPEED signal, to assert a BRAKE-TRIGGER signal; and

a brake controller connected to said motor controller for receiving said BRAKE-TRIGGER signal, said brake controller being configured to assert said BRAKE-ENABLE signal to said motor controller when said BRAKE-TRIGGER signal is asserted.

18. The powered surgical tool of claim 17, wherein said brake controller is further connected to said motor for receiving said MOTOR-SPEED signal and is further configured to cyclically assert said BRAKE-ENABLE signal to said motor controller when said BRAKE-TRIGGER signal is asserted and said MOTOR-SPEED signal indicates said motor rotor is turning and, after said motor rotor has stopped turning, to negate the assertion of said BRAKE-ENABLE signal regardless of the state of said BRAKE-TRIGGER signal.

19. The powered surgical tool of claim 18, wherein said brake controller is further connected to said motor controller to inhibit said motor controller from tieing said motor windings to the power source whenever said BRAKE-TRIGGER signal is asserted.

20. The powered surgical tool of claim 17, wherein said brake controller is further connected to said motor controller to inhibit said motor controller from connecting said motor windings to the power source whenever said BRAKE-TRIGGER signal is asserted.

22. The powered surgical tool of claim 17, wherein said brake controller is configured to assert said BRAKE-ENABLE signal in an on/off pulsed pattern.

23. A powered surgical tool including:

a tool housing;

a motor disposed in said tool housing, said motor being actuatable in response to an application of energization signals thereto;

a motor control module disposed in said tool housing and connected to said motor, said motor control module having a motor control module housing that is fully enclosed and a motor control circuit contained in said motor control module housing, said motor control circuit being configured to supply the energization signals to said motor in response to received motor command signals; and

a switch assembly attached to said tool housing adjacent said module control module housing, said switch assembly including;

a first actuatable switch that extends outside of said tool housing;

a first magnet attached to said first switch and disposed inside of said tool housing adjacent said motor control module housing and configured to move with actuation of said first switch;

a second actuatable switch that extends outside of said tool housing;

a second magnet attached to said second switch and disposed in said tool housing adjacent said motor control module housing and configured to move with actuation of said second switch;

a third magnet movably secured inside said tool housing adjacent said motor control module housing, said third magnet being positioned to be moved as a result of the movement of either said first magnet or said second magnet;

a first magnetic field sensor disposed in said motor control module housing and positioned adjacent said first magnet, said first magnetic field sensor being configured to generate a first motor command signal based on movement of said first magnet;

a second magnetic field sensor disposed in said motor control module housing and positioned adjacent said second magnet, said second magnetic field sensor being configured to generate a second motor command signal based on movement of said second magnet; and

a third magnetic field sensor disposed in said motor control module housing and positioned adjacent said third magnet, said third magnetic field sensor being configured to generate a third motor command signal based on movement of said third magnet, wherein said first, second and third motor command signals are the motor command signals received by said motor control circuit.

24. The powered surgical tool of claim 23, wherein said third magnet is located between said first magnet and said second magnet.

25. A powered surgical tool including:

a motor configured to be rotated in a forward direction and in a reverse direction at variable speeds in response to the application of selected energization signals thereto;

a current sensor connected to said motor to monitor current drawn by said motor, said current sensor being configured to generate an adjustable CUR+ signal representative of the current drawn by said motor wherein said CUR+ signal is based on an adjustable volts/amp ratio established by said current sensor base on a current sensor control signal;

a motor controller connected to said motor for applying energization signals thereto, and to said current sensor for receiving said CUR+ signal, said motor controller circuit being configured to apply energization signals to said motor to cause said motor to rotate at a selected speed in response to the application of a USER-SPEED signal applied thereto and in response to said CUR+ signal and in a specific direction in response to the application of a FORWARD/REVERSE signal thereto, wherein when said FORWARD/REVERSE signal is in a FORWARD/REVERSE state, said motor controller causes said motor to rotate in the forward direction and when said FORWARD/REVERSE signal is in a FORWARD/REVERSE state, said motor controller causes said motor to rotate in the reverse direction;

a plurality of user-actuated switches for generating direction signals representative of a user-selected direction for motor rotation and for generating user-selected speed signals representative of a user-selected motor speed, wherein said switches are configured so that a user can actuate said switches to indicate if said motor should undergo forward, reverse or oscillatory rotation and said direction signals will indicate if said motor should undergo forward, reverse or oscillatory rotation; and

a direction controller connected to said switches for receiving said direction signals and said user-selected speed signals, connected to said motor controller for generating said FORWARD/REVERSE signal and said USER-SPEED signal thereto and connected to said current sensor for generating said current sensor control signal, said direction controller being configured to generate said FORWARD/REVERSE signal and said USER-SPEED signal based on said direction signals and said user-selected speed signals, wherein when said direction signals indicate said motor is to be driven in oscillatory rotation, said direction controller cyclically transitions said FORWARD/REVERSE signal between the FORWARD/REVERSE signal state and the FORWARD/REVERSE signal state and with each said state transition of said FORWARD/REVERSE signal, said direction controller pulses said USER-SPEED signal to a zero-speed USER-SPEED signal so as to cause said motor controller to apply energization signals to said motor based on the zero-speed USER-SPEED signal and to assert said current sensor control signal to cause said current sensor to momentarily base said CUR+ signal on a first volts/amp ratio and to subsequently base said CUR+ signal on a second volts/amp ratio.

26. The powered surgical tool of claim 25, wherein after each said state transition of the FORWARD/REVERSE signal, the first volts/amp ratio upon which said current sensor momentarily basis said CUR+ signal is greater than the second volts/amp ratio upon which said current subsequently basis said CUR+ signal.