Pulleyhjul

Pulleyhjul, commonly referred to as a pulley wheel, is a wheel mounted on an axle with a grooved rim designed to guide a rope, belt, or chain. The groove keeps the drive element seated and reduces friction where the rope or belt changes direction. Pulleys are used alone or as part of pulley systems to alter the direction of a force and, in many cases, to gain mechanical advantage.

Pulleys are categorized by their function and arrangement. A fixed pulley is attached to a support; it changes the direction of the force but does not provide a net gain in lifting power. A movable pulley attaches to the load, effectively doubling the force transmitted and reducing the effort required. Compound pulley systems, or block and tackle, combine multiple pulleys to increase mechanical advantage further. In drive applications, pulley wheels transmit power between shafts via belts, with speed ratios determined by the diameters of the pulleys.

Key components include the grooved rim, the axle and bearings, the pulley housing, and the belt, rope, or chain that runs in the groove. Materials vary from steel, cast iron, and aluminum to durable plastics, chosen based on load, speed, and environmental conditions.

Advantages of pulleyhjuls include the ability to change the direction of force, reduce effort in lifting loads, and transmit power efficiently in belts and drives. Limitations involve wear and friction, belt slippage, misalignment, and limitations set by the strength of the rope or belt. Pulley systems are widely used in construction, transportation, manufacturing, and various everyday mechanisms.