Overhead Cranes - Hoist Basics
Overview:
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 The hoist is mounted on a double-girder, top-running trolley. |
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Lifting Method A hoist lifts and lowers the load. It is almost always affixed to a trolley, providing lateral motion along the crane or gantry bridge. Hoists are typically electric-powered. An electric motor will spin a gearbox, which reduces the speed and provides the correct leverage to rotate a wheel or drum. On a chain hoist, the wheel reels in the chain, lifting the load. On a wire-rope hoist, the drum will rotate, winding in the wire rope and lifting the load. |
 The hoist is suspended from a single-girder, under-running trolley. |
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Configuration Typically a single-girder hoist will be under-running and a double-girder hoist will be top-running. However, all four combinations of single/double-girder and top/under-running are available from most approved vendors. However, under-running applications are not common above fifteen tons rated capacity, and almost non-existent above twenty tons rated capacity. |
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Construction Format A hoist will constructed in one of two formats. The integral package hoist is made of proprietary components with a focus on speed of assembly, minimizing assembly cost, and standardization across one product line. For light to medium duty hoists, this is the most common hoist. The built-up format is constructed by picking the most optimal motor, gearing, drum-size, and other components. Each built-up hoist is custom-designed. The focus is on durability and job-specific performance. A built-up hoist is more durable and easily repairable in comparison to a package hoist, but is also significantly more expensive. A built-up can be triple the cost of a integral package hoist.Click Here to Request Competitive Proposals |
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