<a href="https://en.wikipedia.org/wiki/Patent" class="extiw" title="w:Patent">Learjet US4240597A patent</a> 
<table class="licensetpl" style="display:none"><tbody><tr><td><span class="licensetpl_short">Public domain</span><span class="licensetpl_long">Public domain</span><span class="licensetpl_link_req">false</span><span class="licensetpl_attr_req">false</span>
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<td><b>In general</b>, the contents of United States patents published <b>before</b> March 1, 1989 are in the public domain.<a rel="nofollow" class="external autonumber" href="http://www.uspto.gov/main/ccpubguide.htm">[1]</a>
<p><b>In specific cases</b>, patent applicants and holders may claim copyright in portions of those documents. In those specific cases, applicants are required to identify the portions that are protected under copyright, and are additionally required to state the following within the body of the application and patent:<a rel="nofollow" class="external autonumber" href="http://www.uspto.gov/web/offices/pac/mpep/mpep-9020-appx-r.html#d0e320131">[2]</a> <a rel="nofollow" class="external autonumber" href="http://www.uspto.gov/web/offices/pac/mpep/mpep-9020-appx-r.html#d0e320999">[3]</a>
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<p><i>A portion of the disclosure of this patent document contains material which is subject to (copyright or mask work) protection. The (copyright or mask work) owner has no objection to the facsimile reproduction by any­one of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all (copyright or mask work) rights whatsoever.</i>
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Gates LearJet Corp
patent US4240597A