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A block and tackle is characterized by the use of a single continuous rope to transmit a tension force around one or more pulleys to lift or move a load. Its mechanical advantage is the number of parts of the rope that act on the load. The mechanical advantage of a tackle dictates how much easier it is to haul or lift the load.
A rope looped through a pulley attached to a fixed spot, e.g. a barn roof rafter, and attached to the weight is called a single pulley. It has a mechanical advantage (MA) = 1 (assuming frictionless bearings in the pulley), moving no mechanical advantage (or disadvantage) however advantageous the change in direction may be.
A rope and pulley system—that is, a block and tackle—is characterised by the use of a single continuous rope to transmit a tension force around one or more pulleys to lift or move a load—the rope may be a light line or a strong cable.
In each machine, a force is applied to the device at one point, and it does work moving a load at another point. [23] Although some machines only change the direction of the force, such as a stationary pulley, most machines multiply the magnitude of the force by a factor, the mechanical advantage
In modern times, this kind of rotary leverage is widely used; see a (rotary) 2nd-class lever; see gears, pulleys or friction drive, used in a mechanical power transmission scheme. It is common for mechanical advantage to be manipulated in a 'collapsed' form, via the use of more than one gear (a gearset).
A Z-Drag or Z-Rig is an arrangement of lines and pulleys, effectively forming a block and tackle, that is commonly used in rescue situations. [1] The basic arrangement results in pulling the hauling end 3 times the distance the load is moved, providing a theoretical mechanical advantage of three to one .
Rigging is both a noun, the equipment, and verb, the action of designing and installing the equipment, in the preparation to move objects. A team of riggers design and install the lifting or rolling equipment needed to raise, roll, slide or lift objects such as heavy machinery, structural components, building materials, or large-scale fixtures ...
Vitruvius, a military engineer writing about 28 BC, defined a machine as "a combination of timber fastened together, chiefly efficacious in moving great weights".About a century later, Hero of Alexandria summarized the practice of his day by naming the "five simple machines" for "moving a given weight by a given force" as the lever, windlass, screw for power, wedge, and tackle block (pulley).