A swing yarder is a movable piece of heavy-duty forestry equipment that uses cables to haul logs from the woods to a logging road. A grapple yarder is another name for a swing yarder. To draw in the wires, the swing yarder uses numerous drums. The wires ascend an inclined boom before reaching the far side of a setup. From there, they drop down to collect more logs.
Swing yarders were first built in the 1950s by the Ljungstrom Company in Sweden. Since then, other manufacturers have also produced swing yards. They are used in large timber operations where many trees need to be harvested quickly to make room for new growth. The log yarder can handle tree trunks as large as 110 inches (280 cm) in diameter and 150 feet (45 m) tall.
Also called grapple yarders, these machines were originally designed to harvest small trees on rural property. But modern versions can also cut large trees and even medium-sized ones with enough force to lift them out of the ground. Grapple yarders use steel jaws that close around the trunk of the tree like a clamp. These jaws are attached to chains that can rotate together when pulled by a motorized unit on the yarder. The motor turns one pair of chains while another pair stays still or moves in the opposite direction. This makes it possible to pull one end of the jaw chain across the yarder's arc without affecting the position of the other chain.
Both are rolling devices for smoothing soil and increasing soil contact for sown seeds. A lawn roller, on the other hand, just compresses topsoil, but a cultipacker breaks up clods of earth and compresses the soil. Lawn rollers are often used on grassy lawns, although they may also be used on soil. Cultipackers are usually only used on concrete or asphalt surfaces because they break up clumps of dirt that would otherwise remain after sanding.
Lawn rollers work by pulling a flat surface over the ground at high speeds. This creates a smooth surface without any bumps or holes. The rollers then stop to drop another layer of soil on top of the first. This process is repeated several times until the desired height is reached.
Cultipackers work by dropping small rocks down into the soil. These rocks have been pre-selected by the manufacturer to provide an even distribution of soil when pressed down. As with rolling, this process is done multiple times until the desired height is reached.
The main difference between the two tools is how they are used. With a lawn roller, you need to pull it over the ground and then lift it off the soil again. This process is called "rolling" the lawn. With a cultipacker, smaller rocks are dropped into the soil and the impact disperses the soil as well as breaks up any clumps that might remain after raking or shoveling.
Root grapples are tractor loader attachments that may be attached to machinery to lift, stack, move, push, load, or unload heavy-duty objects.
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A grapple is a hydraulically operated claw with two or more opposed levers that pinch a log or other material to lift or pull them in logging and other technical vehicles. The grapple's tongs are opened and closed using two cables. To move the tongs, one is tightened and the other is loosened. The grapple uses the force generated by this action to grip its load.
Grapples were first used in the 19th century and are still in use today. They can be mounted on trucks or excavators and used in open pit mines or quarries. Grapples can also be hand-held and used for lifting small loads. There are several different types of grapples depending on how they are opened and closed. Mechanical grapples use motors or pneumatics to power their opening and closing mechanisms.
Electric grapples use electric motors to open and close their tongs. These can be single arm or double arm designs. Double arm designs have two separate motors connected to their corresponding tong arms so they can operate separately from each other. This allows the operator to control the depth to which the tongs go when grasping an object.
Pneumatic grapples use air pressure to open and close their tongs. Like electric grapples, pneumatic ones can be single or double arm designs. But instead of using electric motors, they use air valves to connect the arms to their corresponding tongs.