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Chainsaw

technology Maturity 7-9 Next article →

A chainsaw is a portable, handheld power tool designed for cutting through tough materials.

Chainsaw
Chainsaw

While we most often see them used for tree felling or harvesting firewood, they are quite versatile. Professionals use them for limbing, bucking, and pruning trees. They also assist in wildland fire suppression by cutting firebreaks. Some specialized models can even cut through concrete or ice. Modern versions are powered by gasoline, electricity, or lithium batteries.

Chainsaw
Chainsaw

The operation of a chainsaw relies on a precise mechanical chain of events. It begins with the engine, which is usually a two-stroke single-cylinder gasoline engine or an electric motor. In gasoline models, a carburetor manages the air-fuel mixture. This engine drives a mechanism containing a centrifugal clutch and a sprocket.

CentrifugalClutch
CentrifugalClutch

As the engine speed increases, the centrifugal clutch expands to engage a drum. This drum rotates the sprocket, which pulls the cutting chain around a guide bar.

Spur sprocket
Spur sprocket

The chain features many small, sharp teeth made of chromium-plated steel. These teeth are arranged in alternating left-handed and right-handed patterns to ensure efficient cutting. The guide bar includes an edge slot that keeps the chain running in a straight path.

Chainsaws are categorized by their power source and their intended use. Gasoline-powered saws are common because they offer high power-to-weight ratios. They often use a diaphragm carburetor, which allows the saw to operate in any orientation without stalling.

Meßkluppen im Waldmuseum Zwiesel
Meßkluppen im Waldmuseum Zwiesel

Electric models can be corded or cordless. Corded saws were popular from the 1960s, but they are limited by the length of the cable. Cordless saws use lithium batteries and are ideal for light tasks like hedge trimming.

Chainsaw
Chainsaw

For extreme environments, hydraulic power may be used for underwater cutting. There are also different bar types, such as solid steel bars for professionals or laminated bars to reduce weight.

The history of the chainsaw is surprising because it began in the medical field. In the late 18th century, Scottish doctors John Aitken and James Jeffray pioneered a "flexible saw." This device used a fine serrated chain held between two wooden handles. It was used for surgical procedures like symphysiotomy or removing diseased bone.

Bernhard Heine's Osteotome
Bernhard Heine's Osteotome

Around 1830, Bernhard Heine developed the osteotome, a mechanical tool that moved a chain around a guiding blade to cut bone. As medical technology evolved, these surgical saws were replaced by the Gigli twisted-wire saw in 1894.

Transitioning to timber, the first patents for wood-cutting machines appeared in the late 19th century. Frederick L. Magaw received a patent in 1883 for a machine using a chain of links with saw teeth. In 1918, Canadian millwright James Shand developed the first portable chainsaw. Significant advancements followed from inventors like Andreas Stihl and Emil Lerp. Stihl patented an electric chainsaw in 1926 and a gasoline version in 1929. Emil Lerp, the founder of Dolmar, developed the first mass-produced gasoline chainsaw in 1927. These innovations moved the tool from a heavy, two-person machine to a handheld device.

Weight and portability have improved drastically over the decades. Early two-person models were extremely heavy and sometimes required wheels to move. The first one-man chainsaw was introduced in 1950, but it was still quite heavy. By 1959, the average weight had dropped to approximately 12 kg. Today, most standard chainsaws weigh between 4 and 5 kg. Heavy-duty models typically range from 7 to 9 kg. This reduction in weight has made the tool much more accessible for various industries.

Safety is integrated into the design of modern chainsaws through several specialized systems. To reduce fatigue, an anti-vibration system decouples the handles from the engine using springs or rubber. This functions much like a car's suspension to isolate the user from shaking.

Chainsaw1
Chainsaw1

A chain brake is also essential for protecting the operator during a "kickback." If the chain stops suddenly, the centrifugal clutch releases immediately to protect the engine. Some users even modify their saws with different attachments. For example, a hedge trimmer attachment can be fixed to the guide bar for gardening tasks.

Chainsaw
Chainsaw
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🖼️ Images & Media (14)
File:Chainsaw.JPG
Chainsaw.JPG
File:Bernhard Heine's Osteotome.jpg
Bernhard Heine's Osteotome.jpg
File:Meßkluppen im Waldmuseum Zwiesel.JPG
Meßkluppen im Waldmuseum Zwiesel.JPG
File:Electric-chainsaw.jpg
Electric-chainsaw.jpg
Chainsaw in use to cut branches - Tokyo...
File:Ripper Chainsaw.jpg
Ripper Chainsaw.jpg
File:Chainsaw depth gauge.jpg
Chainsaw depth gauge.jpg
File:CentrifugalClutch.jpg
CentrifugalClutch.jpg
File:Spur sprocket.JPG
Spur sprocket.JPG
File:Hedge trimmer modification for chainsaw.jpg
Hedge trimmer modification for chainsaw.jpg
File:Moving the 2016 Tree to the West Lawn (31363813072).jpg
Moving the 2016 Tree to the West Lawn...
File:Chainsaw1.jpg
Chainsaw1.jpg

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