Chain saw tensioning device
This invention relates to a chain saw comprising an engine body on which a guide bar is arranged such that it can be moved in its length direction. The chain saw is provided with a saw chain tensioning device ( 16 ) which is operated manually without the aid of separate tools. The tensioning device comprises a screw ( 19 ) extending mainly parallel to the length direction of the guide bar. A chain tensioning nut is arranged on the screw such that the chain tensioning nut co-operates with the guide bar in order to tension the chain. The screw ( 19 ) is connected to the output shaft of a gear ( 20, 25 ) whose input shaft is connected to a tensioning wheel ( 26 ) accessible for manual adjustment from the outside of the chain saw without separate tools.
1 . Chain saw comprising an engine body ( 10 ) on which a guide bar ( 13 ) is arranged such that it can be moved in its length direction the chain saw being provided with a saw chain tensioning device ( 16 ) which is operated manually without the aid of separate tools and comprises a screw ( 19 ) extending mainly parallel to the length direction of the guide bar ( 13 ) and on which a chain tensioning nut is arranged such that the chain tensioning nut co-operates with the guide bar in order to tension the chain ( 14 ) characterized in that the screw ( 19 ) is connected to the output shaft of a gear ( 20 , 25 ) whose input shaft is connected to a tensioning wheel ( 26 ) accessible for manual adjustment from the outside of the chain saw without separate tools.
2 . Chain saw according to claim 1 characterized in that the input and output shaft are mainly parallel to the length direction of the guide bar ( 14 ).
3 . Chain saw according to claim 1 or 2 characterized in that the chain tensioning nut ( 23 ) is provided with an projection ( 24 ) which is in engagement with the guide bar ( 13 ).
4 . Chain saw according to claim 1 characterized in that the gear ( 20 , 25 ), the tensioning wheel ( 26 ), the screw ( 19 ) and the chain tensioning nut ( 23 ) are integrated into a support unit which is removably arranged on the engine body.
5 . Chain saw according to claim 3 characterised in that the support unit is designed as a cover ( 15 ) that serves as a clamping means for the guide bar.