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Belt And Rope Drive
A belt is a loop of flexible material used to link two or more rotating shafts mechanically, most often parallel. Belts may be used as a source of motion, to transmit power efficiently or to track relative movement. Belts are looped over pulleys and may have a twist between the pulleys, and the shafts need not be parallel. In a two pulley system, the belt can either drive the pulleys normally in one direction (the same if on parallel shafts), or the belt may be crossed, so that the direction of the driven shaft is reversed (the opposite direction to the driver if on parallel shafts). The belt drive can also be used to change the speed of rotation, either up or down, by using different sized pulleys. As a source of motion, a conveyor belt is one application where the belt is adapted to carry a load continuously between two points. History The mechanical belt drive, using a pulley machine, was first mentioned in the text the ''Dictionary of Local Expressions'' by the Han Dynasty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logging
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. Logging is the beginning of a supply chain that provides raw material for many products societies worldwide use for housing, construction, energy, and consumer paper products. Logging systems are also used to manage forests, reduce the risk of wildfires, and restore ecosystem functions, though their efficiency for these purposes has been challenged. 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. Illegal logging refers to the harvesting, transportation, purchase, or sale of timber in violation of laws. The harvesting procedure itself may be illegal, includin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
