Overhead crane

Unlike mobile or construction cranes, overhead cranes are typically used for either manufacturing or maintenance applications, where efficiency or downtime are critical factors.

Single Girder Overhead Crane

The single girder type overhead crane is the most common overhead crane. It is generally used for light applications, normally up to 10 tonnes.

Double Girder Overhead Crane

The double girder overhead crane structure is used for heavier applications up to 125 tons and reaching over 100 feet of span. It can also be used to gain lifting height because the hoist of the double girder overhead crane is placed on the beams and the hook fits between them.

Suspended Overhead Crane

The rails of a suspended overhead crane are secured to the ceiling of the building. The elimination of dedicated support columns provides additional floor space, but limits lifting capacity.

History

In 1876 Sampson Moore in England designed and supplied the first ever electric overhead crane, which was used to hoist guns at the Royal Arsenal in Woolwich, London. Since that time Alliance Machine, now defunct, holds an AISE citation for one of the earliest cranes in the USA market. This crane was in service until approximately 1980, and is now in a museum in Birmingham, Alabama. Over the years important innovations, such as the Weston load brake (which is now rare) and the wire rope hoist (which is still popular), have come and gone. The original hoist contained components mated together in what is now called the built-up style hoist. These built up hoists are used for heavy-duty applications such as steel coil handling and for users desiring long life and better durability. They also provide for easier maintenance. Now many hoists are package hoists, built as one unit in a single housing, generally designed for ten-year life, but the life calculation is based on an industry standard when calculating actual life. See the Hoists Manufacturers Institute site for true life calculation, which is based on load and hours used. In today's modern world for the North American market, there are a few governing bodies for the industry. The Overhead Alliance is a group that represents Crane Manufacturers Association of America, Hoist Manufacturers Institute, and Monorail Manufacturers Association. These product counsels of the Material Handling Industry of America have joined forces to create promotional materials to raise the awareness of the benefits of overhead lifting. The members of this group are marketing representatives of the member companies.

Early manufacture

• 1830: First Crane company in Germany, Ludwig Stuckenholz company.
• 1840: Mass production of overhead cranes starts in Germany.
• 1854: Sampson Moore & Co in Liverpool, England patents a new winch mechanism that allowed the lifting of heavier weights (such as naval guns) by an electric motor.
• 1861: The first steam powered overhead crane is installed by John Ramsbottom at the Crewe Railway workshops. Power was transmitted to the crane from a pulley driven by a stationary engine through an endless cotton rope.
• 1887: The Ludwig Stuckenholz company introduces electrical components to overhead cranes, determining industry design.
• 1910: The first mass-produced electric motor hoist starts in Germany.

Configurations:

While sharing major components, overhead cranes are manufactured in a number of configurations based on applications.

EOT (Electric Overhead Traveling) Crane

EOT cranes are a common type of overhead crane. They are found in many factories and warehouses. These cranes are electrically operated by a control pendant, radio/IR remote pendant, or from an operator cabin attached to the crane.

Rotary overhead crane

This type of overhead crane has one end of the bridge mounted on a fixed pivot and the other end carried on an annular track; the bridge traverses the circular area beneath. This offers improvement over a jib crane by making possible a longer reach and eliminating lateral strains on the building walls.

Polar crane

This type of overhead crane has both ends of the bridge mounted on an annular track. The bridge runs to entire diameter of the track, as opposed to just the radius for a rotary crane. Polar cranes are commonly used in containment buildings at nuclear power stations, fitting their circular, steam pressure containing design.