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Protecting National Treasures is an Open-and Shut Case
 The Rotunda of the National Archives Building
in Washington, D.C. contains display cases housing the
Declaration of Independence, the Constitution, and the Bill of
Rights. Flanking these are two sets of seven cases lining the
Rotunda's curved walls that display the "American Originals"
document collection. Both banks of cases have seven individual
glass lids, each framed in ornate bronze castings.
Custom hinges from
Weber Knapp make it easier to open and close massive lids
on cases protecting the "American Originals" document
collection. The collection includes the Gettysburg
Address, the voting ledger of the First Constitutional
Congress, the Louisiana Purchase agreement, Rosa Parks'
arrest records, and President John F. Kennedy's
Inaugural Address.
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Custom hinges from Weber Knapp make it easier to
open and close massive lids on cases protecting
the "American Originals" document collection.
The collection includes the Gettysburg Address,
the voting ledger of the First Constitutional
Congress, The Louisiana Purchase agreement, Rosa
Parks' arrest records, and President John F.
Kennedy's inaugural Address. |
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The resulting design uses a
combined counterbalance/mechanical linkage that fits between the
wall and document stands. A special gooseneck arm attaches the
hinges to the lid frames. Closed, the lids slope down to 25
degrees and rotate up 60 degrees to their full-open position.
The design prompted no major changes to the cases themselves -
only a fiber optic light bar needed a slight redesign to
accommodate pivoting motion of the arm. NARA says hinges must
last a minimum of 10,000 cycles. Weber Knapp, has successfully
tested the hinge to 36,500 open/close cycles. Lawrence Kren from Machine Design
September 1, 2005 |
