Power tool having object detection

Patent metadata

Field	Value
Publication number	US-12025271-B2
Application number	US-202318332963-A
Country	US
Kind code	B2
Filing date	Jun 12, 2023
Priority date	Aug 30, 2017
Publication date	Jul 2, 2024
Grant date	Jul 2, 2024

Abstract

A power tool and methods are provided for detecting objects (e.g., flesh or other materials) in the operating path of a power tool's output component (e.g., saw blade or drill bit). An object detection sensor in the power tool generates an output signal indicative of a type of material detected in the operating path of the power tool. A power tool controller receives the object detection sensor output and determines when a material in the operating path of the power tool changes. The controller changes operation of a motor of the power tool (e.g., increasing or decreasing speed or stopping the motor) in response to the detected material change. The object detection sensor may include, for example, an RF sensor, a capacitive sensor, a camera, a conductivity probe, or an ultrasound probe.

First claim

What is claimed is:

1. A power tool comprising:
a housing;
a motor within the housing;
an output component coupled to the motor, the output component defining an operating path of the power tool;
an object detection sensor including a radio frequency (“RF”) sensor, the RF sensor configured to transmit a first signal having a first frequency, receive a frequency response signal indicative of an object being proximate to or in the operating path of the power tool, and generate an output signal based on the received frequency response signal; and
a controller connected to the motor and the object detection sensor, the controller including an electronic processor and a memory storing instructions that, when executed by the electronic processor, cause the electronic processor to:
compare the output signal to a plurality of predetermined frequency responses,
select one of the plurality of predetermined frequency responses based on the comparison,
determine a type of material for the object based on the selected one of the plurality of predetermined frequency responses,
maintain, based on the determined type of material of the object being a first type of material, power to the motor, and
inhibit, based on the determined type of material of the object being a second type of material, power to the motor,
wherein the first type of material is different from the second type of material.

2. The power tool of claim 1 , wherein each of the plurality of predetermined frequency responses corresponds to a predetermined type of material.

3. The power tool of claim 1 , wherein, to select one of the plurality of predetermined frequency responses, the instructions are further configured to cause the electronic processor to:
determine a similarity between each of the plurality of predetermined frequency responses and the output signal; and
select a frequency response having a greatest similarity to the output signal.

4. The power tool of claim 1 , wherein the received frequency response signal includes a group of frequencies, and the instructions are further configured to cause the electronic processor to:
determine a primary frequency of the output signal; and
compare the primary frequency to the plurality of predetermined frequency responses.

5. The power tool of claim 1 , wherein the plurality of predetermined frequency responses is stored in a lookup table.

6. The power tool of claim 1 , wherein:
the second type of material is flesh; and
to inhibit the amount of electrical current to the motor, the instructions are further configured to cause the electronic processor to interrupt electrical current to the motor.

7. The power tool of claim 1 , wherein the second type of material includes at least one material selected from the group consisting of flesh, a part of a living being, and a liquid.

8. A power tool comprising:
a housing;
a motor within the housing;
an output component coupled to the motor, the output component defining an operating path of the power tool;
an object detection sensor including a capacitive sensor, the capacitive sensor configured to receive a capacitance signal based on a capacitive field in the operating path of the power tool and generate an output signal based on the received capacitance signal; and
a controller connected to the motor and the object detection sensor, the controller including an electronic processor and a memory storing instructions that, when executed by the electronic processor, cause the electronic processor to:
compare the output signal to a plurality of predetermined capacitance thresholds or ranges,
select one of the plurality of predetermined capacitance thresholds or ranges based on the comparison,
determine a type of material of an object proximate to or in the operating path of the power tool based on the selected one of the plurality of predetermined capacitance thresholds or ranges,
maintain, based on the determined type of material of the object being a first type of material, power to the motor, and
inhibit, based on the determined type of material of the object being a second type of material, power to the motor,
wherein the first type of material is different from the second type of material.

9. The power tool of claim 8 , wherein each of the plurality of predetermined capacitance thresholds or ranges corresponds to a predetermined type of material.

10. The power tool of claim 8 , wherein the output signal is indicative of a measured capacitance of the object, and the measured capacitance is within the selected one of the plurality of predetermined capacitance thresholds or ranges.

11. The power tool of claim 8 , wherein the plurality of predetermined capacitance thresholds or ranges is stored in a lookup table.

12. The power tool of claim 8 , wherein the capacitive sensor includes a capacitive probe that forms a capacitor with the object, and the received capacitance signal changes based on the object that forms the capacitor with the capacitive probe.

13. The power tool of claim 8 , wherein the capacitive sensor includes two capacitive probes positioned opposite to each other, and the received capacitance signal changes in response to the object entering an area between the two capacitive probes.

14. The power tool of claim 8 , wherein the output signal is indicative of a change of capacitance of the capacitive field.

15. The power tool of claim 8 , wherein the second type of material includes at least one material selected from the group consisting of flesh, a part of a living being, and a liquid.

16. A power tool comprising:
a housing;
a motor within the housing;
an output component coupled to the motor, the output component defining an operating path of the power tool;
an object detection sensor including a capacitive sensor, the capacitive sensor configured to receive a capacitance signal based on a capacitive field in the operating path of the power tool and generate an output signal indicative of a measured capacitance of an object being proximate to or in the operating path of the power tool; and
a controller connected to the motor and the object detection sensor, the controller including an electronic processor and a memory storing instructions that when executed by the electronic processor cause the electronic processor to:
compare the output signal to a plurality of capacitance ranges,
maintain an electrical current available to the motor when the measured capacitance is within a first capacitance range indicative of a first type of material,
inhibit the electrical current available to the motor when the measured capacitance is within second capacitance range indicative of a second type of material,
wherein the first capacitance range is different from the second capacitance range, and
wherein the first type of material is different from the second type of material.

17. The power tool of claim 16 , wherein the second capacitance range is lower than the first capacitance range.

18. The power tool of claim 16 , wherein the capacitive sensor includes a capacitive probe that forms a capacitor with the object, and the output signal changes based on the object that forms the capacitor with the capacitive probe.

19. The power tool of claim 16 , wherein the capacitive sensor includes two capacitive probes positioned opposite to each other, and the output signal changes in response to the object entering an area between the two capacitive probes.

20. The power tool of claim 16 , wherein the second type of material inc

Assignees

• Milwaukee Electric Tool Corp

Inventors

• Mergener Matthew J

Classifications

• F16P3/141

  using sound propagation, e.g. sonar · CPC title

• B23Q17/2438

  of an operator or a part thereof · CPC title

• F16P3/147

  using electro-magnetic technology, e.g. tags or radar · CPC title

• B25F5/00

  Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for · CPC title

• B23Q11/0082

  by determining whether the operator is in a dangerous position (B23Q17/2438 takes precedence) · CPC title