Hand-held power tool with a clutch and method for producing a groove in the circumferential wall of a clutch drum of a hand-held power tool

Patent metadata

Field	Value
Publication number	US-9518616-B2
Application number	US-201514669218-A
Country	US
Kind code	B2
Filing date	Mar 26, 2015
Priority date	Apr 5, 2014
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

A hand-held power tool is provided with a drive motor and a clutch connected to the drive motor. The drive motor drives a tool member through the clutch. The clutch has a clutch drum with a circumferential wall provided with an end face. A follower member engages a groove in the circumferential wall of the clutch drum and a driven element is connected to the follower member to be driven by the follower member. The groove extends from the end face of the circumferential wall into the circumferential wall and has a groove bottom and two groove sides positioned opposite each other. The circumferential wall has a protrusion located at the groove bottom. The protrusion has a protrusion thickness measured at the groove bottom that amounts to at least approximately 110% of a wall thickness of the circumferential wall measured at the two groove sides.

First claim

What is claimed is:

1. A hand-held power tool comprising:
a drive motor;
a clutch connected to the drive motor, wherein the drive motor drives a tool member through the clutch;
the clutch comprising a clutch drum and the clutch drum comprising a circumferential wall provided with an end face, wherein the clutch is a centrifugal clutch comprising at least one flyweight, wherein the at least one flyweight in an engaged state of the clutch is resting on an inner side of the circumferential wall;
a follower member engaging a groove provided in the circumferential wall of the clutch drum, the groove extending from the end face of the circumferential wall into the circumferential wall and comprising a groove bottom and two groove sides positioned opposite each other;
a driven element that is connected to the follower member to be driven by the follower member;
wherein the circumferential wall comprises a protrusion located at the groove bottom, wherein the protrusion has a protrusion thickness measured at the groove bottom that amounts to at least approximately 110% of a wall thickness of the circumferential wall measured at the two groove sides.

2. The power tool according to claim 1 , wherein the protrusion has a protrusion width measured parallel to an axis of rotation of the clutch and the protrusion width amounts to from approximately 0.8 mm to approximately 2.0 mm.

3. The power tool according to claim 1 , wherein the protrusion has a protrusion length measured in a circumferential direction of the clutch drum and the protrusion length amounts to from approximately 50% to approximately 200% of a groove width of the groove.

4. The power tool according to claim 1 , wherein the circumferential wall has an inner side and the inner side comprises a raised portion in an area next to the groove bottom, wherein the raised portion is raised relative to an area of the inner side next to the two groove sides.

5. The power tool according to claim 4 , wherein a rise of the raised portion amounts to from approximately 0.05 mm to approximately 0.3 mm.

6. The power tool according to claim 1 , wherein the circumferential wall has an outer side and the outer side comprises a raised portion in an area next to the groove bottom, wherein the raised portion is raised relative to an area of the inner side next to the two groove sides.

7. The power tool according to claim 6 , wherein a rise of the raised portion amounts to from approximately 0.05 mm to approximately 0.3 mm.

8. The power tool according to claim 1 , wherein the circumferential wall in the area next to the groove sides has no protrusion.

9. The power tool according to claim 1 , wherein the groove sides comprise an area adjoining the end face and are positioned in the area adjoining the end face at an angle relative to each other that opens toward the end face.

10. The power tool according to claim 9 , wherein the angle is at least approximately 10°.

11. The power tool according to claim 1 , wherein the groove sides are mirror-symmetrical to each other.

12. The power tool according to claim 1 , wherein the driven element is a pump.

13. A hand-held power tool comprising:
a drive motor;
a clutch connected to the drive motor, wherein the drive motor drives a tool member through the clutch;
the clutch comprising a clutch drum and the clutch drum comprising a circumferential wall provided with an end face;
a follower member engaging a groove provided in the circumferential wall of the clutch drum, the groove extending from the end face of the circumferential wall into the circumferential wall and comprising a groove bottom and two groove sides positioned opposite each other;
a driven element that is connected to the follower member to be driven by the follower member;
wherein the circumferential wall comprises a protrusion located at the groove bottom, wherein the protrusion has a protrusion thickness measured at the groove bottom that amounts to at least approximately 110% of a wall thickness of the circumferential wall measured at the two groove sides;
a brake device comprising a brake belt, wherein the brake belt interacts for braking with an outer side of the circumferential wall.

14. A method for producing a groove in a circumferential wall of a clutch drum of a clutch of a hand-held power tool, the hand-held power tool comprising: a drive motor; a clutch connected to the drive motor, wherein the drive motor drives a tool member through the clutch and the clutch comprises a clutch drum and the clutch drum comprises a circumferential wall provided with an end face; a follower member engaging a groove provided in the circumferential wall of the clutch drum, wherein the groove extends from the end face of the circumferential wall into the circumferential wall and comprises a groove bottom and two groove sides positioned opposite each other; a driven element that is connected to the follower member to be driven by the follower member; wherein the circumferential wall comprises a protrusion located at the groove bottom, wherein the protrusion has a protrusion thickness measured at the groove bottom that amounts to at least approximately 110% of a wall thickness of the circumferential wall measured at the two groove sides; the method comprising:
die cutting a groove with a die-cut groove depth that amounts to approximately 75% up to approximately 95% of a nominal groove depth of the groove and with a die-cut groove width that amounts to approximately 50% up to approximately 110% of a nominal groove width of the groove; and
subsequently plastically deforming a groove bottom of the die-cut groove until the nominal groove depth is reached.

15. The method according to claim 14 , wherein the die-cut groove depth of the die-cut groove is at most 2.0 mm smaller than the nominal groove depth.

Assignees

• Stihl Ag & Co Kg Andreas

Inventors

• Wolf Günter
• Förster Marcel

Classifications

• F16D43/18

  with friction clutching members · CPC title

• B27B17/10 Primary

  Transmission clutches specially designed for chain saws · CPC title

• F16D13/644

  Hub construction · CPC title

• F16D13/62 Primary

  Clutch-bands; Clutch shoes; Clutch-drums (brake-bands, brake-shoes, brake-drums F16D65/00) · CPC title

• B21J5/00

  Methods for forging, hammering, or pressing (for working sheet-metal or metal tubes, rods, or profiles B21D; for working wire B21F); Special equipment or accessories therefor · CPC title