Kedjesåg

摘要

PCT No. PCT/SE87/00379 Sec. 371 Date Mar. 31, 1989 Sec. 102(e) Date Mar. 31, 1989 PCT Filed Aug. 27, 1987 PCT Pub. No. WO88/01559 PCT Pub. Date Mar. 10, 1988.A chain saw has a chain bar (1) with a nose sprocket (5) over which a saw chain (3) circulates. The sprocket (5) is mounted between two nose cheek plates (53). The interior spacing between the plates corresponds to the thickness of the sprocket. The peripheral area of the sprocket with associated teeth at the bar nose extends outside the cheek plates over at least half the sprocket circumference, such that the saw chain passing over the sprocket goes entirely free from the plates and the rest of the bar. Means are arranged for supplying pressurized lubricant via the bar to the sprocket mounting. The lubricant pressure and the gaps between the side surfaces of the sprocket and the inner faces of the cheek plates are such that in operation lubricant passes out through the gaps. Means are also arranged for supplying flushing and cooling medium via the bar for ejection against the saw chain and sprocket both at the place where the chain meshes with the sprocket and at the place where the chain unmeshes with the sprocket. The saw chain (3) is preferably adapted to run free from the bar before and after meshing with the sprocket. Sawing work is thus carried out mainly by the chain supported by the sprocket. The sprocket (5) suitably has a diameter of a magnitude such that both parts of the saw chain converge in a direction away from the nose sprocket.