A skidder is a heavy vehicle type used in logging operations to pull trees that are cut out of the forest in a process called "skidding", where the log is transported from the slaughter site to the landing. There they are loaded into trucks (or in the past, rail cars or flumes), and shipped to the factory. One exception is that in the early days of logging, when the distance from the wooden line to the factory is shorter, the landing stage is eliminated altogether, and the "skidder" will be used as the main road vehicle, instead of truck, train, or flume. Modern skidders can pull trees with cables/winches, like old steam donkey, or grapple or clam-bunk .
Video Skidder
History
The early skidders were pulled by a team of cows, horses or mules. The driver will straddle the cart on the cut wood, where the hanging pin will be positioned to lift the end of the log from the ground. The team pulls the tongue forward, allowing the logs to "slip" between the rolling wheels. This is known as the "slip-tongue wheel" Beginning in the early 1920s, animals were gradually replaced by gasoline-powered crawlers, although some minor operations continued to use horses. Elsewhere, steel "arches" are used behind the crawler. Similar functions to the slip-tongue wheel, the curvature is used to reduce friction by raising one end of the load, which depends from the cable which in turn runs to the back of the arch, & amp; raised or lowered by a winch crawler. Another part similar to the arch is the "bummer", which is just a small trailer to be pulled behind the crawler, on top of which one end of the wooden load will rest.
The early mechanical skidders were steam powered. They travel by train, known as "dummylines" and the felled trees are dragged or "shifted" to the railroads where they are then loaded onto rail cars. Some are just donkey steam, others are more complicated. One of the popular brands is Clyde Skidder, built by Clyde Ironworks in Duluth, Minnesota. The illustrated Skidder Clyde was photographed at the Layang Layang-logging operations near Newton, Mississippi in the early 1920s. Though these machines look big and impractical, they really work in their day. Clyde is able to take logs from four different points at the same time. Each cable, or lead, has a length of about 1000 feet. Once logs are attached and permission signals are sent for retrieval, they can slip at speeds of 1,000 feet per minute. The working conditions around these machines are very dangerous. The biggest one is the Lidgerwood skidder, which not only brings wood to the landing from the cutting location, but also loads it onto the train car, making it a skidder & amp; loader. In New Zealand the cable runs five miles.
Maps Skidder
The modern equivalent
The contemporary skidder is traced or a four-wheeled tractor with diesel, winch and steel engines, a funnel-shaped shield on the back to protect their wheels. They have an articulated rudder and usually a small knife that can be arranged on the front. The operator/logger is protected from falling or flying debris (or cable splits, or rolled) by steel enclosures. They are one of the few logging engines capable of thinning or selective logging in larger timber. Forwarders can carry small short pieces, but if the mature wood will be diluted, the skidder is one of several options to pick up some trees while leaving the other. While selective logging can be done poorly in a number of ways, taking some trees while leaving some trees may be the preferred alternative to taking all the trees.
Skidders can also be used to pull tree stumps, encourage small trees, and preliminary gradations from logging paths known as "skid trails".
One positive thing about skidders is that while the wood is being stacked (drawn), the particles and the seeds of the trees are cultivated into the soil.
One of the disadvantages of skidder logging in thinning operations is damage to the rest of the tree as branches and tree trunks are dragged toward them, tearing the protective skin of the living tree. Another concern is that deep wrinkles in the topsoil are sometimes made by skidders, especially when using tires with chains, which alter the surface runoff patterns and increase the cost of forest reforestation and reforestation.
Version
Cable hoist
In the skidder cable, the cable is rolled up and attached to the pull of the cut wood, then the winch pulls the load toward the skidder. The winch or grapple holds the tree while the skidder drags it to the landing area. Skidder cables are less popular than in the past. They are more labor intensive than the grapple skidder because someone (operator or second person) has to drag the winch line to the log and connect it. This helps where it is impossible to push the machine near the log (as it is on a steep hill).
Skidder Grapple
Alternatively, some skidder has a hydraulic bucket grapple instead of a winch, and a bucket - attached to the skidder by boom - grabs and lifts the wood.
There are three types of skidder graple 'fixed boom'. This type of single-function boom has two hydraulic cylinders, allowing only the boom to be lower in one position. Double function booms (such as images) have four cylinders, which allow to adjust the boom in two different places. The third type allows the grapple boom to be swung from side to side, allowing the spread of trees to be struck at once.
In some areas, loggers have combined hydraulic claws on the sides with their grapple skidder blades, making it possible to accumulate wood in some cases. More commonly in cable skidders, it also allows the transport of back and peak skins when returning from the landing area to the fallen timber.
See also
- Feller buncher
- Michigan recording wheel
- Washington Iron Works Skidder
External links
Media related to Skidders on Wikimedia Commons
- Skidder Tired Logs Development
- RitchieWiki: Skidder
Source of the article : Wikipedia
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