Clutch assembly for a power tool

Patent metadata

Field	Value
Publication number	US-12030168-B2
Application number	US-202217890696-A
Country	US
Kind code	B2
Filing date	Aug 18, 2022
Priority date	Aug 18, 2021
Publication date	Jul 9, 2024
Grant date	Jul 9, 2024

Abstract

A power tool includes a housing, a drive mechanism supported within the housing, a spindle operatively coupled to an output of the drive mechanism such that torque from the drive mechanism rotates the spindle about an axis, and a clutch assembly configured to selectively limit torque transfer from the drive mechanism to the spindle. The clutch assembly includes a plurality of rolling elements, a biasing member configured to bias the plurality of rolling elements into engagement with the output of the drive mechanism, and a sleeve movable along the axis to adjust a torque limit of the clutch assembly by varying a preload of the biasing member. The sleeve is made of a high-temperature, engineering thermoplastic.

First claim

What is claimed is:

1. A power tool comprising:
a housing;
a drive mechanism supported within the housing;
a spindle operatively coupled to an output of the drive mechanism such that torque from the drive mechanism rotates the spindle about an axis; and
a clutch assembly configured to selectively limit torque transfer from the drive mechanism to the spindle, the clutch assembly including
a plurality of rolling elements;
a biasing member configured to bias the plurality of rolling elements into engagement with the output of the drive mechanism; and
a sleeve movable along the axis to adjust a torque limit of the clutch assembly by varying a preload of the biasing member,

wherein the sleeve is made of a high-temperature, engineering thermoplastic.

2. The power tool of claim 1 , wherein the housing includes a gear case made of metal, the gear case having a nose through which the spindle extends, and wherein the drive mechanism is at least partially supported within the gear case.

3. The power tool of claim 2 , wherein the sleeve includes an inner thread, and wherein the gear case includes an outer thread meshed with the inner thread such that rotation of the sleeve about the axis relative to the gear case causes the sleeve to move along the axis relative to the gear case.

4. The power tool of claim 3 , further comprising a collar coupled for co-rotation with the sleeve.

5. The power tool of claim 3 , wherein the inner thread has a first pitch width, wherein the outer thread has a second pitch width, and wherein the first pitch width is greater than the second pitch width.

6. The power tool of claim 5 , wherein the first pitch width is between 10% and 30% greater than the second pitch width.

7. The power tool of claim 1 , wherein the high-temperature, engineering thermoplastic is selected from a group consisting of: polyphthalamide, polyphenylene sulfide, and polyamide 46.

8. The power tool of claim 1 , wherein the high-temperature, engineering thermoplastic is reinforced with glass fibers.

9. The power tool of claim 1 , wherein the high-temperature, engineering thermoplastic includes 50% glass fibers by weight.

10. The power tool of claim 1 , wherein the biasing member includes a wave spring.

11. A power tool comprising:
a housing;
a drive mechanism supported within the housing;
a spindle operatively coupled to an output of the drive mechanism such that torque from the drive mechanism rotates the spindle about an axis; and
a clutch assembly configured to selectively limit torque transfer from the drive mechanism to the spindle, the clutch assembly including
a plurality of rolling elements;
a biasing member configured to bias the plurality of rolling elements into engagement with the output of the drive mechanism; and
a sleeve movable along the axis to adjust a torque limit of the clutch assembly by varying a preload of the biasing member,

wherein the sleeve is movable to a lockout position in which the biasing member is fully compressed to prevent axial displacement of the plurality of rolling elements, and
wherein the biasing member includes a wave spring.

12. The power tool of claim 11 , wherein the clutch assembly further includes a cage coupled for co-rotation with the spindle, and wherein the plurality of rolling elements is received in respective bores formed in the cage.

13. The power tool of claim 12 , wherein the clutch assembly further includes a plurality of pins aligned with the plurality of rolling elements and a washer engaging a front end of each of the plurality of pins.

14. The power tool of claim 13 , wherein a first end of the biasing member abuts the sleeve, and a second end of the biasing member abuts the washer.

15. The power tool of claim 14 , wherein the sleeve is made of a high-temperature, engineering thermoplastic.

16. The power tool of claim 15 , wherein the high-temperature, engineering thermoplastic has a glass transition point of at least 70 degrees Celsius, a Young's modulus of at least 10,000 MPa at 120 degrees Celsius, and a tensile strength of at least 140 MPa at 120 degrees Celsius.

17. The power tool of claim 11 , wherein the sleeve includes threads.

18. A power tool comprising:
a housing including a gear case;
a drive mechanism supported at least partially within the gear case;
a spindle operatively coupled to an output of the drive mechanism such that torque from the drive mechanism rotates the spindle about an axis; and
a clutch assembly configured to selectively limit torque transfer from the drive mechanism to the spindle, the clutch assembly including
a plurality of rolling elements;
a biasing member configured to bias the plurality of rolling elements into engagement with the output of the drive mechanism; and
a sleeve movable along the axis to adjust a torque limit of the clutch assembly by varying a preload of the biasing member,

wherein the sleeve includes an inner thread defining a first pitch width,
wherein the gear case includes an outer thread defining a second pitch width and meshed with the inner thread such that rotation of the sleeve about the axis relative to the gear case causes the sleeve to move along the axis relative to the gear case, and
wherein the first pitch width is greater than the second pitch width.

19. The power tool of claim 18 , wherein the sleeve is movable to a lockout position in which the biasing member is fully compressed to prevent axial displacement of the plurality of rolling elements.

20. The power tool of claim 18 , wherein the first pitch width is between 10% and 30% greater than the second pitch width.

Assignees

• Milwaukee Electric Tool Corp

Inventors

• Yue Brian J
• Dales Hugh A

Classifications

• B25B21/00

  Portable power-driven screw or nut setting or loosening tools; (details or components, e.g. casings, bodies, of portable power-driven tools not particularly related to the operation performed B25F5/00; {for mounting or dismounting wheels B60B29/006}); Attachments for drilling apparatus serving the same purpose (machines B23P19/06) · CPC title

• B25B23/141

  Mechanical overload release couplings · CPC title

• F16D43/206

  moving axially between engagement and disengagement · CPC title

• B25F5/02

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

• B25F5/001 Primary

  Gearings, speed selectors, clutches or the like specially adapted for rotary tools · CPC title