Filament cutterhead for a brushcutter

Patent metadata

Field	Value
Publication number	US-9826679-B2
Application number	US-201514957251-A
Country	US
Kind code	B2
Filing date	Dec 2, 2015
Priority date	Dec 23, 2014
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A filament cutterhead is provided for mounting on the drive shaft of a brushcutter. The filament cutterhead includes a housing with a circumferential wall wherein a first wall opening for a cutting filament is formed. A filament spool arranged in the housing is rotatable relative to the housing. A filament channel with a filament inlet segment is provided in a partition wall of the filament spool. The filament channel extends from the filament inlet segment past the hub to a filament outlet segment which is assigned a second wall opening in the circumferential wall. The filament outlet segment is at an offset (v) with respect to the filament inlet segment in the circumferential direction of the hub. The mouth of the filament inlet segment and the mouth of the filament outlet segment lie within an outside diameter (A) of the partition wall and open into a pass-through space.

First claim

What is claimed is:

1. A filament cutterhead for mounting on a drive shaft of a brushcutter, the filament cutterhead comprising:
a cup-shaped housing defining a peripheral wall having first and second wall openings formed therein for a cutting filament;
a filament spool for accommodating the cutting filament thereon;
said filament spool being mounted in said cup-shaped housing so as to be rotatable relative thereto and said filament spool having a hub defining a rotational axis;
said hub having a disc-shaped partition wall arranged thereon and said disc-shaped partition wall having a maximum outer diameter (A);
said partition wall partitioning said filament spool into an upper winding section and a lower winding section;
said partition wall defining a rim and having a filament-guiding filament channel formed therein;
said filament channel having a filament-guiding filament inlet segment disposed in said rim of said partition wall;
said filament inlet segment defining a longitudinal center axis lying on a first radius (R 1 ) passing through said rotational axis of said hub;
said longitudinal center axis of said filament inlet segment defining an imaginary extension thereof which passes through said first wall opening in a pregiven rotational position of said filament spool;
said filament channel having a filament-guiding filament outlet segment formed in said rim of said partition wall and lying opposite said filament inlet segment;
said filament channel extending from said filament inlet segment so as to pass by said hub and to said filament outlet segment;
said filament outlet segment being assigned to said second wall opening;
said filament outlet segment being at an offset (v) to said longitudinal center axis of said filament inlet segment viewed in the peripheral direction of said hub;
said filament inlet segment and said filament outlet segment having an inlet mouth and an outlet mouth, respectively;
said inlet mouth and said outlet mouth being disposed so as to lie within said maximum outer diameter (A) of said partition wall; and,
filament guiding pass-through spaces being configured to be clear of a filament guide and being formed in said partition wall between corresponding ones of said mouths and said maximum outer diameter (A) of said partition wall.

2. The filament cutterhead of claim 1 , wherein at least one of said filament inlet segment and said filament outlet segment is configured as a linear channel segment.

3. The filament cutterhead of claim 1 , wherein said partition wall defines a plane and said filament outlet segment defines a longitudinal center axis; and, said longitudinal center axis of said filament inlet segment and said longitudinal center axis of said filament outlet segment are spaced from each other at a distance (a) in said plane of said partition wall.

4. The filament cutterhead of claim 1 , wherein:
said inlet mouth and said outlet mouth define respective centers;
said first radius (R 1 ) passes from said rotational axis of said hub through said center of said inlet mouth;
a second radius (R 2 ) passes from said rotational axis of said hub through said center of said outlet mouth;
said first and second wall openings lie on a connecting line passing through said rotational axis of said hub;
said first radius (R 1 ) and said connecting line conjointly define an inlet angle (β e );
said second radius (R 2 ) and said connecting line conjointly define an outlet angle (β a and,
said inlet angle (β e ) and said outlet angle (β a ) are configured to be unequal.

5. The filament cutterhead of claim 4 , wherein said inlet angle (β e ) is configured to be less than said outlet angle (β a ).

6. The filament cutterhead of claim 5 , wherein said inlet angle (β e ) is zero.

7. The filament cutterhead of claim 1 , wherein at least one of said pass-through spaces is configured to be wider viewed in the peripheral direction of said hub than the width of said inlet mouth and/or said outlet mouth corresponding thereto likewise viewed in said peripheral direction of said hub.

8. The filament cutterhead of claim 1 , wherein:
said hub has an inner radius;
said partition wall defines a plane;
said filament channel includes a filament channel segment connecting said filament inlet segment and said filament outlet segment to each other;
said filament channel segment is bent in said plane of said partition wall to form a bent channel segment; and,
said bent channel segment has a bending radius greater than said inner radius of said hub.

9. The filament cutterhead of claim 1 , wherein said filament channel is a first filament channel; said filament inlet segment is a first inlet segment and said filament outlet segment is a first outlet segment; and, wherein said filament cutterhead further comprises:
a second filament channel having a second filament inlet segment and a second filament outlet segment;
said second filament channel extending in said partition wall from said second wall opening to said first wall opening; and,
said hub lying between said first and second filament channels.

10. The filament cutterhead of claim 9 , wherein said first filament outlet segment and said second filament inlet segment lie ahead of said second wall opening and lie mutually adjacent in the peripheral direction of said partition wall.

11. The filament cutterhead of claim 1 , wherein:
said partition wall defines a plane;
in said plane of said partition wall, said filament channel has a filament assist outlet next to said filament inlet segment of said filament channel; and, said filament assist outlet defines a longitudinal center axis parallel to said longitudinal center axis of said filament inlet segment.

12. The filament cutterhead of claim 11 , wherein said filament assist outlet is formed by a linear channel segment of said filament channel.

13. The filament cutterhead of claim 12 , wherein said filament inlet segment and the channel segment of said filament assist outlet transitions into said filament channel via a common channel widening in said filament channel.

14. The filament cutterhead of claim 9 , wherein each of said first and second filament channels has a filament inlet segment at one and the same one of said wall openings; and, the imaginary extension of said longitudinal center axis of the corresponding filament inlet segment passes through said one wall opening.

15. The filament cutterhead of claim 14 , wherein said filament inlet segment of said first filament channel and said filament inlet segment of said second filament channel conjointly form a common central inlet ahead of the wall opening corresponding thereto.

16. The filament cutterhead of claim 15 , wherein said central inlet transitions into a corresponding one of said filament channels via a channel junction and a deflector.

17. The filament cutterhead of claim 1 , wherein guide bushings having respective filament pass-through openings are held in corresponding ones of said wall openings; and, each of said guide bushings has an inner side facing toward said rim of said partition wall and said inner side is configured with a catch contour.

18. The filament cutterhead of claim 17 , wherein said catch contour has an opening width (F) which covers over said filament inlet segment and said filament outlet segment.

19. The filament cutterhead of claim 17 , wherein said hub defines an upward direction; the catch contour has two longitudinal ribs running in said upward direction; and, said longitudinal ribs project up to ahead

Assignees

• Stihl Ag & Co Kg Andreas

Inventors

• Lang Sven
• Rethaber Achim

Classifications

• A01D34/4161 Primary

  Means for feeding cutter line · CPC title

• A01D34/4166 Primary

  Mounting or replacement of the lines · CPC title