Lightweight Jack
Richard Dudgeon, Inc. (RDI), Bridgeport, Connecticut supplies
hydraulic jacking equipment, along with engineering and technical
support, for heavy lifting projects. The company rents and sells
standard jacks and also designs and manufactures custom jacks
for specific applications. Among the company's products are a
line of high pressure jacks/load cells that evolved from a prototype
system developed for a NASA heavy lifting project.
A group of Dudgeon 700-ton load cells/hydraulic jacks, each
of which weighs only 79 pounds.
The project involved lifting segments of giant antennas in
NASA's Deep Space Network (DSN), which is managed by Jet Propulsion
Laboratory. The DSN is composed primarily of three communication
complexes located at Goldstone, California; Madrid, Spain; and
Canberra, Australia; they are about 120 degrees of longitude
apart to permit continuous tracking of a spacecraft by at least
one station at all times, despite Earth's rotation. Key facilities
are three giant antennas, one at each location, that support
deep space (interplanetary) missions; each measures 70 meters
in diameter, is 22 stories high and weighs some 8,000 tons.
In 1990, JPL discovered that modifications to the antennas
over the years had redistributed weight to the point where bearing
failure-and possible collapse of the antenna-was threatened.
JPL asked RDI to devise a solution for simultaneous measurement
of several key load points within the bearing housings of the
70-meter antennas, an initial step in correcting the alignment.
The job called for a heavy lifting load cell system of extraordinary
capability. It had to be ultralight for portability (it had to
be carried to the bearing housing level 120 feet above ground
via narrow ladders); it had to be extremely powerful to lift
the weight of the structure above the bearings; and it had to
be thin enough to fit between load points that measure as little
as .025 inches. Additionally, it had to be developed within a
tight time frame.
A comparison of the NASA technology load cell (red) and a
3,000-pound standard hydraulic jack of the same lifting capacity.
RDI assembled a project team composed of its own experts augmented
by those of a number of Connecticut firms that assisted in the
design, development and ultimately the manufacture of a complete
synchronous load cell system. Prototype development took only
six weeks and the system was used successfully in the DSN project.
RDI subsequently commercialized the technology with its Dudgeon
High Pressure Ultrathin Pancake Jacks/Hydraulic Load Cells, which
are designed for applications requiring minimal lift but high
portability. They are ultralight as well as ultrathin; a system
capable of lifting 700 tons weighs only 79 pounds, where a conventional
jack of similar lift capability might weigh half a ton. Available
in a capacity range from 50 to 2,000 tons, they are intended
for such applications as bridge weighing/lifting, heavy industrial
and turbine weighing/positioning, and weighing/positioning of
utilities and power plant equipment.
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