Mechanical advantage device advantage for a screw can be calculated using the following equation: where Note that the actual mechanical advantage of a screw "system" is greater, as a screwdriver or other screw driving system has a mechanical advantage as well. 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
Hoist (device) Hoist (device) A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The most familiar form is an elevator, the car of which is raised and lowered by a hoist mechanism. Most hoists couple to their loads using a lifting hook. The basic hoist has two important characteristics to define it: Lifting medium and power type. The lifting medium is either wire rope, wrapped