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Huletts at the PRR ore docks at Cleveland. The near Hulett is discharging into the hopper, while the next is lowering its bucket into the hold.

The Hulett automatic ore unloader was invented by George Hulett of Ohio in the late 1800s; he received a patent for his invention in 1898. The first working machine was built the following year at Conneaut Harbor in Conneaut, Ohio. It was successful, and many more were built along the Great Lakes, especially the southern shore of Lake Erie to unload boats full of taconite from the iron mines near Lake Superior. Substantial improvements were later made on the design by Samuel T. Wellman. It is these second-generation Huletts which continue to stand to this day.[1]

A Hulett's bucket in the foreground, while another scoops ore from the hold. The operator's cab is in the leg, behind the aperture above the bucket and below the circular sprocket.

The electrically operated Hulett unloader runs on two sets of parallel tracks along the face of the docks, one near the edge and one further back, with normally enough distance for four sets of railroad tracks in between. Steel towers, riding on wheeled trucks, support girders that run from front to back, perpendicular to the dock face.

Along these girders runs a carriage which can move toward or away from the dock face. This in turn carries a large walking beam which can be raised or lowered; at the dock end of this is a vertical column with a large scoop bucket on the end. A parallel beam is mounted half-way down this column to keep the column vertical as it is raised or lowered. The machine's operator, stationed in the vertical beam above the bucket for maximum cargo visibility, could spin the beam at any angle. The scoop bucket is thus lowered into the ship's hold, closed to capture a quantity (10 tons approx.) of ore, raised, and moved back toward the dock.

To reduce the required motion of the carriage, a moving receiving hopper runs between the main girders. It is moved to the front for the main bucket to discharge its load, and then moves back to dump it into a waiting railroad car, or out onto a cantilever frame at the back to dump the load onto a stockpile.

Discharging the travelling hopper's load into a waiting hopper car.

The Hulett can move along the dock to line up with the various holds on an ore boat. Once the hold is mostly empty, the Hulett cannot easily finish the job itself. Early on, workmen would descend into the hold and shovel the remaining ore into the Hulett's bucket; later on, a wheeled excavator would be chained to the Hulett's bucket and lowered into the hold to fill the Hulett.

The Hulett machine revolutionised iron ore shipment on the Great Lakes. Previous methods of unloading lake freighters, involving hoists and buckets and much hand labor, cost approximately 18¢/ton. Unloading with a set of Huletts cost only 5¢/ton. Furthermore, unloading only took 5-10 hours, as opposed to days for previous methods. Lake boats changed to accommodate the Hulett unloader, and became much larger; doubling in length and quadrupling in capacity.

By 1913, 54 Hulett machines were in service; two were built at Lake Superior (unloading coal) and five at Gary, Indiana, but the vast majority were along the shores of Lake Erie. The additional unloading capacity they brought helped permit a greater than doubling of the ore traffic in the 1900–1912 period. A total of approximately 75 Huletts were built. One was installed in New York City to unload garbage. They were unsuited to saltwater environments because they could not adjust for rising and falling tides, and few were so used.

HAER diagram of a Hulett Unloader in Cleveland, Ohio

The lake's Huletts were used until about 1992, when self-unloading boats were standard on the American side of the lake. Most, if not all, have since been scrapped. In 1999, only six remained, the group of four in Cleveland, Ohio the oldest. Another set was used unloading barges of coal in South Chicago until 2002 and are still standing at present time.

In spite of the Cleveland machines being on the National Register of Historic Places and designated as a Historic Mechanical Engineering Landmark, they were demolished in 2000 by the Cleveland Port Authority to enable development of the land they were located on. The Port Authority disassembled and retained two Huletts, to enable their reconstruction at another site, but the reconstruction has not yet happened.

References

  1. ^ Snow, Richard F. (Fall 1987). "Lifting Iron". American Heritage 3 (2). http://www.americanheritage.com/articles/magazine/it/1987/2/1987_2_4.shtml. Retrieved 2007-01-26.  

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