Motorized surgical tool with sensor assembly in the handle for monitoring the rotational orientation of the motor rotor

Patent metadata

Field	Value
Publication number	US-10004517-B2
Application number	US-201715405462-A
Country	US
Kind code	B2
Filing date	Jan 13, 2017
Priority date	Jun 28, 2005
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A powered surgical tool that includes a housing with a head and a handle that extends from the head. An electric motor is disposed in the head. A trigger extends from the handle. There is a void space in the handle. A plate separates the motor from the handle. Internal to the handle void space there is a rotor sensor and a control circuit. The rotor sensor is able to monitor the magnetic fields emitted by the motor rotor and that pass through the plate. The control circuit receives signals from the rotor sensor representative of the rotational orientation of the rotor and is further able to monitor the actuation of the trigger. Based on the rotor orientation signals and the actuation of the trigger, the control circuit generates signals that result in the selective generation of power signals to the motor rotor.

First claim

What is claimed is:

1. A powered surgical tool, said tool comprising:
a housing shaped to have a head and a handle that extends from said head, said handle having a void space;
a motor disposed in said housing head, said motor having a plurality of windings and a rotor formed with a plurality of magnets wherein said rotor is rotatably mounted in said housing head;
a coupling assembly connected to said rotor for releasably attaching a surgical attachment to said rotor so that said rotor can actuate the attachment;
at least one manually actuatable trigger moveably mounted to said handle;
a rotor sensor disposed in the housing handle void space so as to be spaced from said motor, said rotor sensor configured to monitor a magnetic field of said rotor and to, as a function of the rotor magnetic field, generate a plurality of analog rotor orientation signals representative of a rotational orientation of said rotor;
a control circuit disposed in the housing handle void space, said control circuit configured to: receive from said rotor sensor the analog rotor orientation signals; monitor the actuation of said trigger; and selectively generate a plurality of signals that result in a plurality of power signals being applied to said windings of said motor, said control circuit including:
a signal processor that receives the analog rotor orientation signals and, based on the levels of the analog rotor orientation signals, converts the analog rotor orientation signals into a plurality of plural bit digital signals representative of the rotational orientation of said rotor; and
a motor controller to which the plural bit digital signals representative of the rotational orientation of said rotor are applied that, based on the plural bit digital signals representative of the rotor orientation and the actuation of said trigger, selectively generates the signals that result in the power signals being selectively applied to the windings; and

a plate disposed in said housing between, on one side, said motor and, an opposed side, said rotor sensor and said control circuit that separates said rotor sensor and said control circuit from said motor, said plate being formed from material that allows magnetic fields to pass thereacross so that said rotor sensor can monitor changes in the magnetic field emitted by said rotor magnets.

2. The powered surgical tool of claim 1 , wherein:
a magnet is mounted to said trigger; and
said control circuit includes a sensor for monitoring the variations in the magnetic field emitted by the trigger magnet as a function of the actuation of said trigger.

3. The powered surgical tool of claim 1 , wherein:
said rotor sensor includes a plurality of rotor sensing units, each said rotor sensing unit generating a separate analog rotor orientation signal representative of the orientation of said rotor; and
said signal processor receives the analog rotor orientation signals from the individual said rotor sensing units and, based on the plural analog rotor orientation signals, generates the plural bit digital signals representative of an orientation of said rotor magnets.

4. The powered surgical tool of claim 3 , wherein said rotor sensor includes a maximum of two said rotor sensing units.

5. The powered surgical tool of claim 1 , wherein:
said rotor sensor includes a first and a second rotor sensing units that each generate a plurality of analog rotor orientation signals representative of the orientation of said rotor; and
said signal processor receives the analog rotor orientation signals from said first and said second rotor sensing unit and is configured to:
at motor start-up, convert the analog rotor orientation signals into the plural bit digital signals representative of the rotational orientation of said rotor based on the signals from both said first and second rotor sensing units; and
after motor start-up, convert the analog rotor orientation signals into the plural bit digital signals representative of the rotational orientation of said rotor based on the signals from a single one of said rotor sensing units.

6. The powered surgical tool of claim 1 , wherein said rotor sensor includes a single rotor sensing unit that outputs the analog rotor orientation signals.

7. The powered surgical tool of claim 6 , wherein the control circuit is configured to: during start-up of said motor, use a first process to, based on the analog rotor orientation signals, convert the analog rotor orientation signals into the plural bit digital signals representative of the rotational orientation of said rotor; and after start-up of said motor, use a second process to convert the analog rotor orientation signals into the plural bit digital signals representative of the rotational orientation of said rotor.

8. The powered surgical tool of claim 1 , wherein said plate is part of a control module that contains said rotor sensor and said control circuit.

9. The powered surgical tool of claim 1 , wherein:
a circuit board is disposed in the housing handle void space; and
said rotor sensor and at least a portion of said control circuit are mounted to said circuit board.

10. The powered surgical tool of claim 1 , wherein:
a circuit board is disposed in the housing handle void space and associated with said circuit board there is a notch;
at least a portion of said control circuit is mounted to said circuit board; and
said rotor sensor is seated in said notch.

11. The powered surgical tool of claim 10 , wherein said circuit board is formed to define a void that extends inwardly from an edge of said circuit board, the void being the notch in which said rotor sensor is seated.

12. The powered surgical tool of claim 1 , wherein said plate is formed from metal.

13. The powered surgical tool of claim 1 , wherein said plate is a separate component from said housing and is secured to said housing.

14. The powered surgical tool of claim 1 , wherein at least a portion of said control circuit is encased in a potting compound.

15. The powered surgical tool of claim 1 , wherein said rotor sensor is a Hall sensor.

16. A powered surgical tool, said tool comprising:
a housing shaped to have a head and a handle that extends from said head, said handle having a void space;
a motor disposed in said housing head, said motor having a plurality of windings and a rotor formed with a plurality of magnets wherein said rotor is rotatably mounted in said housing head;
a coupling assembly connected to said rotor for releasably attaching a surgical attachment to said rotor so that said rotor can actuate the attachment;
a first plate internal to said housing located between said motor and the handle void space, said first plate being at least partially formed from material that allows magnetic fields emitted by said rotor to cross into the handle void space;
at least one manually actuatable trigger moveably mounted to said handle;
a rotor sensor disposed in the handle void space, said rotor sensor configured to monitor the magnetic fields of said rotor that pass through said first plate and to, as a function of the rotor magnetic fields, generate analog rotor orientation signals representative of a rotational orientation of said rotor; and
a control circuit disposed in the handle void space, said control circuit configured to: receive said rotor orientation signals; monitor the actuation of said trigger; and selectively generate signals that result in power signals being applied to said windings of said motor, said control circuit including:
a signal processor that receives the analog rotor orientation signals and,

Assignees

• Stryker Corp

Inventors

• Philipp Christopher

Classifications

• A61B34/20

  Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis · CPC title

• A61B17/32002

  with continuously rotating, oscillating or reciprocating cutting instruments · CPC title

• A61B2017/00734

  battery operated · CPC title

• A61B17/1622 Primary

  Drill handpieces (A61B17/1626, A61B17/1628 take precedence) · CPC title

• H02P7/06

  for regulating or controlling an individual DC dynamo-electric motor by varying field or armature current · CPC title