Static discharge mitigation of power tools

Patent metadata

Field	Value
Publication number	US-2021252617-A1
Application number	US-202017052459-A
Country	US
Kind code	A1
Filing date	Apr 28, 2020
Priority date	May 1, 2019
Publication date	Aug 19, 2021
Grant date	—

Abstract

A power tool is provided with a coating to distribute static electricity away from the surface of the handle of the tool. The tool includes a handle configured to be grasped by a user. The handle includes a surface and a first material having a first surface resistivity. The tool includes a coating covering 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 power tool comprising:
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.

2 . The power tool of claim 1 , wherein static charge induced by the power tool follows a path from the tool to ground, and wherein the path includes the handle.

3 . The power tool of claim 2 , further comprising a printed circuit board, wherein the path of static charge from the tool to ground is conducted away from the printed circuit board.

4 . The power tool of claim 1 , wherein the coating is less than 0.1 mm thick.

5 . The power tool of claim 1 , wherein the coating has a surface resistance of less than 108 ohms.

6 . The power tool of claim 1 , wherein the coating is a conductive paint.

7 . The power tool of claim 1 , further comprising an air ionizer positioned adjacent an inlet of an airflow path within the tool, wherein the air ionizer is configured to introduce positively charged particles into the airflow path through the inlet.

8 . The power tool of claim 1 , further comprising a conductive grate positioned adjacent an inlet of an airflow path within the tool, wherein the metal grate is configured to repel charged particles from entrance to the airflow path through the inlet.

9 . The power tool of claim 1 , further comprising a static rope configured to conduct induced static electricity away from the power tool.

10 . The power tool of claim 9 , wherein the static rope is fastened to the handle to allow discharge of the accumulated static charge without the static rope contacting a user.

11 . The power tool of claim 1 , further comprising conductive tinsel configured to conduct induced static electricity away from the power tool.

12 . The power tool of claim 1 , further comprising conductive spiked features and a blade, wherein the conductive spiked features are configured to conduct induced static electricity away from the blade.

13 . The power tool of claim 12 , further comprising a blade guard, wherein the conductive spiked features are fastened or integrally formed with the blade guard adjacent the blade.

14 . The power tool 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.

15 . A power tool comprising:
a handle configured to be grasped by a user, the handle including a base material and an additive, wherein the handle has a first volume resistivity and a first surface resistivity, wherein the base material has a second volume resistivity and a second surface resistivity, and wherein the additive causes the first volume resistivity and the first surface resistivity of the handle to be less than the second volume resistivity and the second surface resistivity of the base material, respectively, such that the base material and the additive are configured to distribute static electricity away from the handle.

16 . The power tool of claim 15 , wherein static charge induced by the power tool follows a path from the tool to ground, and wherein the path includes the handle.

17 . The power tool of claim 15 , wherein the additive has a third volume resistivity less than the second volume resistivity of the base material, and wherein the additive has a third surface resistivity less than the second surface resistivity of the base material.

18 . The power tool of claim 17 , further comprising a second additive having a fourth volume resistivity and a fourth surface resistivity, the first additive and the second additive together causing the first volume resistivity and the first surface resistivity of the handle to be less than the second volume resistivity and the second surface resistivity of the base material, respectively.

19 . The power tool of claim 15 , wherein the handle is formed in an injection molding process.

20 . The power tool of claim 15 , wherein the handle is formed of plastic.

21 . The power tool of claim 15 , wherein the handle includes a first clamshell half and an opposed, second clamshell half, and wherein the additive is dispersed throughout both the first clamshell half and the second clamshell half.

22 . The power tool of claim 15 , wherein additive is evenly dispersed throughout the handle.

23 . The power tool of claim 15 , wherein the handle includes a first region and a second region, and wherein unequal amounts of additive are dispersed throughout the first region and the second region.

24 . The power tool of claim 15 , further comprising an air ionizer positioned adjacent an inlet of an airflow path within the tool, wherein the air ionizer is configured to introduce positively charged particles into the airflow path through the inlet.

25 . The power tool of claim 15 , further comprising a metal grate positioned adjacent an inlet of an airflow path within the tool, wherein the metal grate is configured to repel charged particles from entrance to the airflow path through the inlet.

26 . The power tool of claim 15 , further comprising a static rope disposed within handle, wherein the static rope is configured to accumulate static charge from the handle and store the static charge for a controlled discharge.

27 . The power tool of claim 26 , wherein the static rope is fastened to the handle to allow discharge of the accumulated static charge without the static rope contacting the user.

28 . The power tool of claim 15 , further comprising conductive tinsel configured to conduct induced static electricity away from the power tool.

29 . The power tool of claim 15 , further comprising conductive spiked features and a blade, wherein the conductive spiked features are configured to conduct induced static electricity away from the blade.

30 . The power tool of claim 29 , further comprising a blade guard, wherein the conductive spiked features are fastened or integrally formed with the blade guard adjacent the blade.

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

• H05F1/02 Primary

  by surface treatment · CPC title

• B23D45/16 Primary

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

• B25F5/02

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

• B23D59/008

  comprising computers · CPC title

• B24B27/06

  Grinders for cutting-off · CPC title