| 摘要 |
Chain saw comprises a cutting chain 2 turning around a drive sprocket 7 and a guide bar 4, which can be immobilized on the body 5 of the saw by a jamming device 11, 12. The tension in the chain can be reduced or increased by moving the guide bar 4 towards or away from the drive sprocket 7. The chain saw further comprises a pushing device 8, 9. When the jamming device 11, 12 is loosened the pushing device 8, 9 tends to automatically move the guide bar 4 away from the drive sprocket 7 and maintain the tension in the chain 2. The pushing device 8, 9 comprises a slide 9 and a helical spring 8. The rear end 4d of the guide bar 4 rests against the rear end 21 of the slide. One end of the helical spring is connected to the body 5 and the other end is connected to the front end 9a of the slide. The invention automaticaly maintains the chain's tension.
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