Drum hoist Drum hoists are typically composed of an electric brake motor and a multi-line helically-grooved drum. Helical drums are preferable to smooth drums for cable longevity and the precise and repeatable control of travel. Drum hoists are used for motor-assist, engaging an operating line, and dead-haul, engaging the lift lines, applications. A dead-haul drum hoist uses the single drum to support all the lift lines running from the head block of a line set. The lift lines neatly wrap and unwrap in a side-by-side arrangement on the drum as it is spun by the motor. As a lift line coils and uncoils from the drum of a drum hoist, its fleet angle (angle of a line between drum and sheave) changes. Excessive fleet angles (e.g., greater than 1.5–2.0°) cause unpredictable line behavior and can damage lines, blocks, and drums. As a result, fleet angles limit how close a dead-haul drum hoist can be mounted to the head block (usually about 10 feet). A moving drum hoist, or traveling drum hoist, is a variation on the traditional drum hoist. Moving drum hoists effectively eliminate the fleet angle between drum and block by shifting the drum along its axis as it spins. The amount of shift per drum revolution is equal to the pitch of the drum's helical groove. With the fleet angle problem resolved, moving drum hoists can combine drum and head block into a single, relatively compact, unit for mounting to fly loft structure, with a corresponding reduction of installation cost. Yo-yo, pile-up, or pilewind, hoists use yo-yo type devices instead of helically grooved drums. The yo-yos lines are coiled into overlapping layers of cable in the narrow slots. The pile-up drum hoists are usually used in low load. As the hoists are narrower than helically grooved drum hoists, these can be used in the places with limited space. Pile-up drum hoists can be mounted in many locations including ceiling, floor or wall mounting. Typical applications are to have a pile-up drum hoist with many pulleys to control a batten. Since the line is piled up on itself, this type of drum hoist provides a zero fleet angle solution. Line shaft hoist Line shaft hoists are typically composed of an electric brake motor, line shaft (drive shaft) and evenly spaced single-line drums aligned above the batten pick points. By placing an individual drum over each pick point, line shaft