“Patents are published as part of the terms of granting the patent to the inventor. Subject to limited exceptions reflected in 37 CFR 1.71(d) & (e) and 1.84(s), the text and drawings of a patent are typically not subject to copyright restrictions.” See: http://www.uspto.gov/main/ccpubguide.htm
However:
37 CFR 1.84(s) Copyright or Mask Work Notice (§ 1.71(d) [...]
