Static discharge mitigation of power tools

Patent metadata

Field	Value
Publication number	US-12023748-B2
Application number	US-202017052459-A
Country	US
Kind code	B2
Filing date	Apr 28, 2020
Priority date	May 1, 2019
Publication date	Jul 2, 2024
Grant date	Jul 2, 2024

Abstract

A cut-off saw configured to remove material from a workpiece, the cut-off saw includes a motor, a blade, a drive assembly, a handle, and a coating. The blade is capable of removing material from the workpiece upon contact between the blade and the workpiece. The drive assembly is coupled to the motor and the blade and is configured to transmit torque from the motor to the blade. The handle is configured to be grasped by a user, and includes a surface and a first material having a first surface resistivity. The coating covers at least a portion of the handle. The coating is configured to distribute static electricity away from the surface. The coating is made of a second material having a second surface resistivity less than the first surface resistivity.

First claim

What is claimed is:

1. A cut-off saw configured to remove material from a workpiece, the cut-off saw comprising:
a motor;
a blade capable of removing material from the workpiece upon contact between the blade and the workpiece;
a drive assembly coupled to the motor and the blade, the drive assembly being configured to transmit torque from the motor to the blade;
a handle configured to be grasped by a user, the handle including a surface and a first material having a first surface resistivity; and
a coating covering at least a portion of the handle configured to distribute static electricity away from the surface,
wherein the coating is made of a second material having a second surface resistivity less than the first surface resistivity,
wherein static charge induced by the cut-off saw follows a path from the cut-off saw to ground, and wherein the path passes through the handle.

2. The cut-off saw of claim 1 , further comprising a printed circuit board, wherein the path of static charge from the cut-off saw to ground is conducted away from the printed circuit board.

3. The cut-off saw of claim 1 , wherein the coating is less than 0.1 mm thick.

4. The cut-off saw of claim 1 , wherein the coating has a surface resistance of less than 10 8 ohms.

5. The cut-off saw of claim 1 , wherein the coating is a conductive paint.

6. The cut-off saw of claim 1 , further comprising an air ionizer positioned adjacent an inlet of an airflow path within the cut-off saw, wherein the air ionizer is configured to introduce positively charged particles into the airflow path through the inlet.

7. The cut-off saw of claim 1 , further comprising a conductive grate positioned adjacent an inlet of an airflow path within the cut-off saw, wherein the metal grate is configured to repel charged particles from entrance to the airflow path through the inlet.

8. The cut-off saw of claim 1 , further comprising a static rope configured to conduct induced static electricity away from the handle.

9. The cut-off saw of claim 8 , wherein the static rope is fastened to the handle to allow discharge of the accumulated static charge without the static rope contacting a user.

10. The cut-off saw of claim 1 , further comprising conductive tinsel configured to conduct induced static electricity away from the blade.

11. The cut-off saw of claim 1 , further comprising conductive spiked features, wherein the conductive spiked features are configured to conduct induced static electricity away from the blade.

12. The cut-off saw of claim 11 , further comprising a blade guard, wherein the conductive spiked features are fastened or integrally formed with the blade guard adjacent the blade.

13. The cut-off saw of claim 1 , wherein the surface is an exterior surface of the handle, and wherein the coating is applied to an interior surface of the handle.

Assignees

• Milwaukee Electric Tool Corp

Inventors

• Obermann Timothy R
• Gallagher Patrick D
• Bernitt Jessie L
• Carlson Mitchell
• Bartlett Timothy J
• Huber Alex
• Dubnicka Travis J
• Ertl Daniel R
• Thorson Troy C
• Staszak Kevin
• Jin Austin

Classifications

• H05F3/02

  by means of earthing connections · CPC title

• B24B27/06

  Grinders for cutting-off · CPC title

• B25F5/02

  Construction of casings, bodies or handles {(B25F5/006, B25F5/008 take precedence)} · CPC title

• B23D59/008

  comprising computers · CPC title

• B23D45/16 Primary

  Hand-held sawing devices with circular saw blades · CPC title