This article needs additional citations for verification. A chainsaw is a portable, mechanical saw which cuts with a set of teeth attached to a rotating chain that runs along a guide bar. Typical of the earliest chainsaws, this Dolmar saw is operated stihl chainsaw service manual free pdf two men.
The origin is debated, but a chainsaw-like tool was made around 1830 by the German orthopaedist Bernhard Heine. Bens of San Francisco on January 17, 1905. His intent being to fell giant redwoods. The first portable chainsaw was developed and patented in 1918 by Canadian millwright James Shand.
1947, the forerunner of Pioneer Saws. Ltd and part of Outboard Marine Corporation, the oldest manufacturer of chainsaws in North America. The early models were heavy, two-person devices with long bars. Often chainsaws were so heavy that they had wheels like dragsaws. Other outfits used driven lines from a wheeled power unit to drive the cutting bar. After World War II, improvements in aluminum and engine design lightened chainsaws to the point where one person could carry them. Chainsaws have almost entirely replaced simple man-powered saws in forestry.
They come in many sizes, from small electric saws intended for home and garden use, to large “lumberjack” saws. Members of military engineer units are trained to use chainsaws as are firefighters to fight forest fires and to ventilate structure fires. There are three main types of chainsaw sharpeners – Handheld File, Electric Chain Saw and Bar Mounted. The traditional carburetor needs to be adjusted, i. Electrically influenced carburetors make all adjustments automatically. These systems are provided by most large chain saw producers. Husqvarna calls its “Autotune,” and it is commonly standard on most saws of the 5XX saw series.
Many saws offer a Winter and Summer mode of operation. F where inside the cover a hole is opened leaving warm air to the air filter and carburetor to prevent icing. In warmer environment the hole is closed and both units are not ventilated with warm air. To ensure clean air supply to the carburetor, chainsaw producers offer different filters with fine or less fine mesh. In clean surrounding air a less fine filter can be used, in dusty environment the other. This leads to the engine dying.
The engines are designed so that they may be operated in different positions, upside-down or tilted 90 degrees. Typically a centrifugal clutch and sprocket. The centrifugal clutch expands with raising spinning speed towards a drum. On this drum sits either a fixed sprocket or an exchangeable one. An edge slot guides the cutting chain. Specialized loop-style bars, called bow bars, were also used at one time for bucking logs and clearing brush, although they are now rarely encountered due to increased hazards of operation.
The lower part of the chain runs in the gauge. Here the lubrication oil is pulled by the chain to the nose. This is a very important mechanism. At the end of the saw power head there are two oil holes, one on each side. These holes must match with the outlet of the oil pump. The pump pumps the oil through the hole in the lower part of the gauge.
Saw bar producers provide a large variety of bars matching different saws. Through this hole grease is pumped, typically each tank filling to keep the nose sprocket well lubricated. Here one or two bolts from the saw run through. It depends on the size of the saw if one or two bolts are installed. Laminated bars These bars consist of different layers to reduce the weight of the bar. Solid bars These bars are solid steel bars intended for professional use. They have commonly an exchangeable nose since the sprocket at the bar nose wears out faster than the bar.
Safety bars These bars are laminated bars with a small sprocket at the nose. The small nose reduces the kickback effect. Such bars are used on consumer saws. Some way to adjust the tension in the cutting chain so that it neither binds on nor comes loose from the guide bar. The tensioner is either operated by turning a screw or a manual wheel.