Trimmer head for a trimmer

Patent metadata

Field	Value
Publication number	US-9320195-B2
Application number	US-201414196048-A
Country	US
Kind code	B2
Filing date	Mar 4, 2014
Priority date	Mar 6, 2013
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A trimmer head for a trimmer has a base member having a trimmer line opening. A clamping device arranged in the base member clamps a trimmer line that defines a cutting plane when rotated. The clamping member of the clamping device is rotatably disposed on a pivot bolt having a pivot axis positioned in a plane that is parallel to the cutting plane. The clamping member is spring-loaded by a clamping spring into a clamping position. The trimmer line is secured in the clamping position between a clamping surface and the clamping member. A centrifugal force acting on the trimmer line loads the clamping member in the clamping position. A U-shaped bracket has bracket legs connected by a stay. The clamping member is positioned between the bracket legs. The pivot bolt is supported on the bracket leg ends. The stay of the U-shaped bracket forms the clamping surface.

First claim

What is claimed is:

1. A trimmer head for a trimmer comprising:
a base member having a trimmer line opening;
an elongate trimmer line that is secured by a clamping action in the base member and that projects through the trimmer line opening from an interior of the base member to an exterior of the base member, wherein the trimmer line, upon rotation of the trimmer head, defines a cutting plane of the trimmer line;
a clamping device arranged in the base member and providing the clamping action acting on the trimmer line, wherein the clamping device comprises a clamping member, a pivot bolt, and a clamping spring;
wherein the clamping member is disposed on the pivot bolt so as to be rotatable, wherein a pivot axis of the pivot bolt is positioned in a plane that is approximately parallel to the cutting plane;
wherein the clamping member has a clamping position and is spring-loaded by the clamping spring in a clamping direction into the clamping position;
wherein the trimmer line is secured in the clamping position between a clamping surface of the clamping device and the clamping member and wherein the clamping member engages the trimmer line in the clamping position such that a centrifugal force acting on the trimmer line additionally loads the clamping member in the clamping direction;
a U-shaped bracket comprising a stay and oppositely positioned bracket legs with a first end and a second end, respectively, wherein the stay connects the first ends of the bracket legs to each other and wherein the second ends form bracket leg ends;
wherein the clamping member is positioned between the bracket legs of the U-shaped bracket;
wherein the pivot bolt is supported on the bracket leg ends;
wherein the stay of the U-shaped bracket forms the clamping surface.

2. The trimmer head according to claim 1 , wherein the bracket leg ends each have a slot, wherein the pivot bolt is inserted radially into the slots and is secured by the clamping spring in the slots of the bracket leg ends.

3. The trimmer head according to claim 1 , wherein the U-shaped bracket comprises a stop adapted to limit a rotational movement of the clamping member, wherein the stop is a bent tab integrally formed on one of the bracket legs.

4. The trimmer head according to claim 1 , wherein the clamping spring is a leg spring that is disposed on the pivot bolt, wherein the clamping spring has a first spring leg engaging the clamping member and a second spring leg secured in a locking recess of a first one of the bracket leg ends.

5. The trimmer head according to claim 4 , wherein the locking recess is formed in an end face of said first bracket leg end.

6. The trimmer head according to claim 4 , wherein the clamping spring is arranged between the bracket legs.

7. The trimmer head according to claim 6 , wherein the clamping member is positioned off-center between the bracket legs.

8. The trimmer head according to claim 7 , wherein the base member has a wall element that projects into the U-shaped bracket.

9. The trimmer head according to claim 7 , further comprising a space-filling insertion part inserted into a free space that is defined between the clamping member and a first one of the bracket legs.

10. The trimmer head according to claim 9 , wherein the insertion part is a three-dimensionally shaped sheet metal part that is penetrated by the pivot bolt and that is secured with an anti-rotation device on the U-shaped bracket.

11. The trimmer head according to claim 10 , wherein the anti-rotation device is integrally formed on the insertion part as a securing flange which is bent out of a plane of the insertion part, wherein the securing flange engages a slot of said first bracket leg.

12. The trimmer head according to claim 9 , wherein the insertion part comprises a first section and a second section, wherein the first section is resting flat on said first bracket leg and wherein the second section is positioned tightly next to the clamping member.

13. The trimmer head according to claim 4 , wherein the pivot bolt has an end section that projects past said first bracket leg end and wherein the clamping spring is arranged on the end section of the pivot bolt outside of the U-shaped bracket.

14. The trimmer head according to claim 1 , wherein the clamping surface of the U-shaped bracket and a lower edge of the trimmer line opening are disposed at a same level in the base member.

15. The trimmer head according to claim 1 , wherein the trimmer line opening is formed by an outlet sleeve that is secured in a circumferential wall of the base member.

16. The trimmer head according to claim 15 , wherein the outlet sleeve has a rim that engages a receptacle provided on the base member.

17. The trimmer head according to claim 1 , wherein at least one lateral surface of the clamping member has a countersunk hole for reducing the weight of the clamping member.

18. The trimmer head according to claim 17 , wherein the countersunk hole is a bore.

19. The trimmer head according to claim 18 , wherein the bore is a penetrating bore having a bore axis that is parallel to the pivot bolt.

20. The trimmer head according to claim 1 , wherein the bracket is made of metal and is made by bending a metal strip.

Assignees

• Stihl Ag & Co Kg Andreas

Inventors

• Weimer Ina
• Keller Katharina
• Neumaier Thomas
• Stark Thomas
• HäBERLEIN JüRGEN

Classifications

• A01D34/4166 Primary

  Mounting or replacement of the lines · CPC title

• A01D34/4165

  Mounting of the cutter head · CPC title

• A01D34/416 Primary

  Flexible line cutters · CPC title