Mechanical advantage device Mechanical advantage device A simple machine that exhibits mechanical advantage is called a mechanical advantage device - e.g.: Consider lifting a weight with rope and pulleys. 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 "single movable pulley" has an MA of 2 (assuming frictionless bearings in the pulley). Consider a pulley attached to
Lifting bag a hazardous operation with high risk of entanglement in an uncontrolled lift or sinking. If a single bag is insufficient, multiple bags may be used, and should be distributed to suit the load. There are also lifting bags used on land as short lift jacks for lifting cars or heavy loads or lifting bags which are used in machines as a type of pneumatic actuator which provides load over a large area. These lifting bags of the AS/CR type are for example used in the brake mechanism of rollercoasters. The volume of the bag determines its lifting capacity: each litre