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High Lead Logging
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 (or cable drums). 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'. The "high lead" feature is added by elevating both lines near the winch or 'head' end. This is accomplished by running the lines through a block (pulley) called the "head block" because it is on the head end of the project. Early on, it wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cable Logging
High Lead logging in Western Oregon 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 (Austria, Switzerland, Czech Republic, France, Italy). The cables can be rigged in several configurations. There are two classes; # High lead logging, in which a simple loop of cable runs from the yarder out through pulley blocks anchored to stumps at the far end of the cut. # Skyline, in which a carriage, pulled by hauling cables, runs along a skyline cable, providing vertical lift to the logs. There are other varieties of loading systems as well. While skyline logging requires additional setup, the vertical lift of the skyline allows faster yarding, which can outweigh the additional labor costs, especially on larger harvest units. Since the 1980s grapple yarders have become popular. Skyline and grapple yarding, however, require more complex, and expensiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spar (tree)
A spar tree is the tree used as the highest anchor point in a high lead cable logging setup. The spar tree is selected based on height, location and especially strength and lack of rot in order to withstand the weight and pressure required. Once a spar tree is selected, a climber would remove the tree's limbs and top the tree (a logging term for cutting off the top of the tree). Block and tackle is then affixed to the tree and cabling is run. A "high climber" is the member of the logging crew who scales the tree, limbs it, and tops it. Selecting a tree as a spar is a particularly important task, so the strength and importance of the spar came to hold symbolic meaning for early loggers of the West. The use of spar trees in logging is now rare, having been replaced since the 1970s by portable towers, called yarders 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, d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yarder
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. Early Yarders The early yarders were steam powered. They traveled on railroads, known as "dummylines", and felled trees were dragged or "skidded" to the railroad where they were loaded onto rail cars. Popular brands included Willamette, Skagit, Washington, Tyee, or Lidgerwood and Clyde, built by Clyde Ironworks in Duluth, Minnesota. Although these machines appear to be large and cumbersome, they were highly productive. The Clyde was capable of retrieving logs from four different points at the same time. Each cable, or lead, was approximately 1000 feet in length. Once the logs were attached and a clearance signal was sent for retrieval, the logs could be skidded at a speed of 1000 feet per minute, which is around 10 mp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscar Wirkkala
Oscar Wirkkala (; October 30, 1880 – January 25, 1959) was a Finnish-American logger and inventor who spent much of his life in the Pacific Northwest. Background Oscar Wirkkala was born in Kaustinen, Finland. His father Abraham and brother Andrew arrived in America first, working at a saw mill in Cosmopolis, Washington, to save money to pay for the migration of the rest of the family. Oscar arrived next, in 1898, followed closely by his mother, a sister, and three younger brothers. The family lived in the Naselle and Deep River area of Washington from 1899 to 1905. Career Wirkkala invented and developed the high lead method of logging. This skyline (or "spar") method, ideally suited for steep terrain, revolutionized the industry. He also invented important pieces of that industry's machinery used during the first half of the 20th century, including the ubiquitous choker hook. His first patent was granted in 1917, and was for a four-drum donkey engine used in his high lead log ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winch
A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the tension of a rope or wire rope (also called "cable" or "wire cable"). In its simplest form, it consists of a spool (or drum) attached to a hand crank. Traditionally, winches on ships accumulated wire or rope on the drum; those that do not accumulate, and instead pass on the wire/rope (see yacht photo above), are called capstans. Despite this, sailboat capstans are most often referred to as winches. Winches are the basis of such machines as tow trucks, steam shovels and elevators. More complex designs have gear assemblies and can be powered by electric, hydraulic, pneumatic or internal combustion drives. It might include a solenoid brake and/or a Mechanical brake stretch wrapper, mechanical brake or ratchet (device), ratchet and pawl which prevents it unwinding unless the pawl is retracted. The rope may be stored on the winch. When trimming a line on a sailboat, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulley
A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt. In the case of a pulley supported by a frame or shell that does not transfer power to a shaft, but is used to guide the cable or exert a force, the supporting shell is called a block, and the pulley may be called a sheave. A pulley may have a groove or grooves between flanges around its circumference to locate the cable or belt. The drive element of a pulley system can be a rope, cable, belt, or chain. The earliest evidence of pulleys dates back to Ancient Egypt in the Twelfth Dynasty (1991-1802 BCE) and Mesopotamia in the early 2nd millennium BCE. In Roman Egypt, Hero of Alexandria (c. 10-70 CE) identified the pulley as one of six simple machines used to lift weights. Pulleys are assembled to form a block and tackle in order to provide mechanical advantage to apply large forces. Pulleys are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guy Wires
A guy-wire, guy-line, guy-rope, or stay, also called simply a guy, is a tensioned cable designed to add stability to a free-standing structure. They are used commonly for ship masts, radio masts, wind turbines, utility poles, and tents. A thin vertical mast supported by guy wires is called a guyed mast. Structures that support antennas are frequently of a lattice construction and are called "towers". One end of the guy is attached to the structure, and the other is anchored to the ground at some distance from the mast or tower base. The tension in the diagonal guy-wire, combined with the compression and buckling strength of the structure, allows the structure to withstand lateral loads such as wind or the weight of cantilevered structures. They are installed radially, usually at equal angles about the structure, in trios and quads. As the tower leans a bit due to the wind force, the increased guy tension is resolved into a compression force in the tower or mast and a late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lidgerwood
Lidgerwood was a historic American engineering company famous for its boilers, winches, scrapers, hoists and cranes, particularly ones that helped build the Panama Canal. They later built logging yarders and aerial tramway An aerial tramway, sky tram, cable car, ropeway, aerial tram, telepherique, or seilbahn is a type of aerial lift which uses one or two stationary ropes for support while a third moving rope provides propulsion. With this form of lift, the grip ...s, cable cars or ropeways. Lidgerwood winches had at least two specific railroad maintenance uses, and were used by railroad customers to move railroad freight cars into position for loading and unloading (and to move other cars out of the way). As the successor company is still in business it is probable that they continue to be used in the railroad industry for moving cars through current (2013) times. Railroad wheels need to have a specific profile. As the profile wears into degraded shapes their perfor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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