A swing yarder is a mobile piece of heavy duty forestryequipment used for pulling logs from the woods to a logging road with cables. The swing yarder is also known as a grapple yarder.
In any logging operation, it is necessary to transport the harvested tree from the stump to a landing for transport to market (usually on a truck). If the ground is relatively flat it may be possible to transport the tree or logs cut from the tree on a wheeled or tracked machine. However, if the ground is too steep for the operation of such machinery, it is common practice to rig some sort of a cable system for moving the wood. The swing yarder is one of several varieties of machines that have been used for this purpose.
The swing yarder has several drums to pull in the cables. The cables run up an angled boom and then to the far side of a setting. By using two cables set up like a clothes line, the rigging can be pulled out and logs can be pulled across a logging setting where the trees have been previously felled. This machine is most suitable for steep ground where it is difficult to access the logs with other machinery. Swing yarders can also be used in flatter areas with lighter loads.
While there are various rigging options, the most common one uses a grapple that can be lowered onto a logs and closed via the cable system. Using a grapple avoids the need for people in the setting to attach chokers to the log. Choker setting as a profession is a very dangerous occupation.
The main difference between a swing yarder and a tower yarder is that the upperworks is mounted on a large slewing bearing. This bearing permits the boom and cable system to be 'swung' across a setting without relocating the machine. An experienced operator uses timing and cable tension to swing the grapple to the desired location. In practice, however, the main benefit of a swinging machine is that once the logs are yarded up to the machine, they can be swung to the side and landed. This allows the machine to be positioned in a small area such as on a road, and to land (set down) the logs on the road behind (or in front of) the machine. By contrast a tower has no options on where to set the logs---so the tower has to be positioned back from the break of the hill so as to leave a landing area on the downhill side of the machine, the logs can only be pulled up to near the tower and then lowered to the ground making it necessary for a shovel (log loader) to also be present to remove the logs once landed. Implicitly a swing machine does not need to be as tall as a tower machine particularly in steep ground because the swing machine can be set right up to the 'edge' of the steep ground while the tower must be set back from the 'edge' to allow landing space.
Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. In forestry, the term logging is sometimes used narrowly to describe the logistics of moving wood from the stump to somewhere outside the forest, usually a sawmill or a lumber yard. In common usage, however, the term may cover a range of forestry or silviculture activities.
Lumberjacks are mostly North American workers in the logging industry who perform the initial harvesting and transport of trees for ultimate processing into forest products. The term usually refers to loggers in the era when trees were felled using hand tools and dragged by oxen to rivers.
A block and tackle or only tackle is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift heavy loads.
Excavators are heavy construction equipment consisting of a boom, dipper, bucket and cab on a rotating platform known as the "house". The house sits atop an undercarriage with tracks or wheels. They are a natural progression from the steam shovels and often mistakenly called power shovels, as power shovels may have similar looking buckets. All movement and functions of a hydraulic excavator are accomplished through the use of hydraulic fluid, with hydraulic cylinders and hydraulic motors. Due to the linear actuation of hydraulic cylinders, their mode of operation is fundamentally different from cable-operated excavators which use winches and steel ropes to accomplish the movements.
A crane is a type of machine, generally equipped with a hoist rope, wire ropes or chains, and sheaves, that can be used both to lift and lower materials and to move them horizontally. It is mainly used for lifting heavy objects and transporting them to other places. The device uses one or more simple machines to create mechanical advantage and thus move loads beyond the normal capability of a human. Cranes are commonly employed in transportation for the loading and unloading of freight, in construction for the movement of materials, and in manufacturing for the assembling of heavy equipment.
Running rigging is the rigging of a sailing vessel that is used for raising, lowering, shaping and controlling the sails on a sailing vessel—as opposed to the standing rigging, which supports the mast and bowsprit. Running rigging varies between vessels that are rigged fore and aft and those that are square-rigged.
A skidder is any type of heavy vehicle used in a logging operation for pulling cut trees out of a forest in a process called "skidding", in which the logs are transported from the cutting site to a landing. There they are loaded onto trucks, and sent to the mill. One exception is that in the early days of logging, when distances from the timberline to the mill were shorter, the landing stage was omitted altogether, and the "skidder" would have been used as the main road vehicle, in place of the trucks, railroad, or flume. Modern forms of skidders can pull trees with a cable and winch, just like the old steam donkeys, or with a hydraulic grapple either on boom or on the back of the frame (clambunk skidder).
A harvester is a type of heavy forestry vehicle employed in cut-to-length logging operations for felling, delimbing and bucking trees. A forest harvester is typically employed together with a forwarder that hauls the logs to a roadside landing.
A derrick is a lifting device composed at minimum of one guyed mast, as in a gin pole, which may be articulated over a load by adjusting its guys. Most derricks have at least two components, either a guyed mast or self-supporting tower, and a boom hinged at its base to provide articulation, as in a stiffleg derrick. The most basic type of derrick is controlled by three or four lines connected to the top of the mast, which allow it both to move laterally and cant up and down. To lift a load, a separate line runs up and over the mast with a hook on its free end, as with a crane.
A grappling hook or grapnel is a device that typically has multiple hooks attached to a rope; it is thrown, dropped, sunk, projected, or fastened directly by hand to where at least one hook may catch and hold on to objects. Generally, grappling hooks are used to temporarily secure one end of a rope. They may also be used to dredge for submerged objects.
A grapple is a hook or claw used to catch or hold something. A ship's anchor is a type of grapple, especially the "grapnel" anchor.
A steam donkey or donkey engine is a steam-powered winch once widely used in logging, mining, maritime, and other industrial applications.
A yarder is piece of logging equipment that uses a system of cables to pull or fly logs from the stump to a collection point. It generally consists of an engine, drums, and spar, but has a range of configurations and variations, such as the swing yarder.
Cable logging, also referred to as skyline logging, is a logging method primarily used on the West Coast of North America with yarder, loaders, and grapple yarders, but also in Europe.
High lead logging is a method of cable logging using a spar, yarder and loader. It was developed by Oscar Wirkkala. It is accomplished with two lines (cables) and two winches. The mainline or yarding line extends out from one winch, while a second usually lighter line called the haulback line extends out from the other winch to a 'tail block' or pulley at the tail (back) end of the logging site, and passes through the tail block and connects to the main line. Butt rigging is installed where the two lines join and the logs are hooked to the butt rigging with chokers. The procedure is to wind up the main line and the logs are pulled in, wind up the haulback and the butt rigging is pulled out for more logs or another 'turn'.
A chain is a serial assembly of connected pieces, called links, typically made of metal, with an overall character similar to that of a rope in that it is flexible and curved in compression but linear, rigid, and load-bearing in tension. A chain may consist of two or more links. Chains can be classified by their design, which can be dictated by their use:
The Washington Winch sits in the forests of eastern Victoria near Swifts Creek and is also known as the Washington Iron Works Skidder.
A choker setter or choke setter is a logger who attaches cables to logs for retrieval by skidders or skylines. The work process involves the choker setter wrapping a special cable end (choker) around a log and then moving clear so the yarding engineer can pull the log to a central area. In clearcutting, fallers will typically cut down all the trees and limb and buck them into logs before the choke setters and others arrive to remove the logs.
Skyline logging is a form of cable logging in which harvested logs are transported on a suspended steel cable from where the trees are felled to a central processing location.
Heli-logging, or helicopter logging, is a method of logging that uses helicopters to remove cut trees from forests by lifting them on cables attached to a helicopter. Helicopter logging is often used in inaccessible areas of forests. Because the use of helicopters reduces the level of infrastructure required to log in a specific location, the method also helps to reduce the environmental impact of logging. It also can increase the productivity in these remote areas.
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