Filament type trimmer
US4253238A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 10, 1980 |
| Grant date | Mar 3, 1981 |
| Priority date | — |
| Expiry date | Jan 10, 2000 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA01D34/416
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In a filament type trimmer a filament is wound on a storage spool in a rotating housing and exits through an opening in a rim portion of the housing. When the extending portion of the filament is rotating freely, it extends approximately radially from the housing. However, when it hits a relatively stationary object, it is deflected rearwardly so as to extend approximately tangentially from the housing. To avoid high stresses in the exiting portion of the filament, the exit opening is inclined rearwardly so that when the filament is deflected rearwardly by striking an object, it extends in a tangential line off of the spool, thereby avoiding bending stresses at the exit opening.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.