Trimmer head with automatic trimmer line feed mechanism
US9253942B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Sep 20, 2011 |
| Grant date | Feb 9, 2016 |
| Priority date | — |
| Expiry date | May 10, 2033 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA01D34/4165
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An automatic-feed trimmer head for a vegetation trimming machine. A spool is positioned within the interior of a housing. A cam guide formation is disposed atop the top flange of the spool. The cam guide formation defines a pathway. A cam arm is provided that is mounted to the housing with a pivot connection. The cam arm has a cam projection that extends into the pathway. A spring is provided that biases the cam arm into a first orientation. In the first orientation, the shape of the pathway enables the cam projection to move only in a first direction. The cam arm moves about the pivot connection from its first orientation to a second orientation when the trimmer head assembly is rotated above a predetermined rotational speed. When the cam arm is in its second orientation trimmer line is unwound from the spool.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.