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The fixed pulley on the upper shaft is driven at constant speed by a belt from the power source. The loose pulley ('idler') allows the machine to be stopped in isolation – necessary for changing speed. The stepped pulleys (left) provide three drive speeds for the machine tool (not shown), depending on which pair of pulleys is connected by the ...
A pulley is a wheel on an axle or shaft enabling a taut cable or belt passing over the wheel to move and change direction, or transfer power between itself and a shaft. A sheave or pulley wheel is a pulley using an axle supported by a frame or shell ( block ) to guide a cable or exert force.
The end disk and hub may be one piece. The locking assembly may also be replaced with a hub and bushing on lower tension pulleys. The shell is also referred to as the rim in some parts of the world. The pulley shaft is typically sized following CEMA B105.1 in the Americas or AS 1403 in Australia.
The following stresses are induced in the shafts.. Shear stresses due to the transmission of torque (due to torsional load).; Bending stresses (tensile or compressive) due to the forces acting upon the machine elements like gears and pulleys as well as the self weight of the shaft.
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A dumb pulley can lift very large masses a short distance. It consists of two fixed pulleys of unequal radii that are attached to each other and rotate together, a single pulley bearing the load, and an endless rope looped around the pulleys. To avoid slippage, the rope is usually replaced by a chain, and the connected pulleys by sprockets.
Consider the set of pulleys that form the moving block and the parts of the rope that support this block. If there are n of these parts of the rope supporting the load F B, then a force balance on the moving block shows that the tension in each of the parts of the rope must be F B /n. This means the input force on the rope is F A =F B /n.
Another 1872 author wrote: "Gear wheels are used in England to transmit the power of the engine to what is usually called the jack shaft." [3] By 1892, the quotes were gone, but the use remained the same. [4] The pulleys on the jackshafts of mills or power plants were frequently connected to the shaft with clutches.