Your patent claims a device that "attach[es]" to a "flexible" thingy.
Does "attach" require that the device touch only the outside of the thingy? Or can it also attach to the thingy's innards? And must the thingy flex "easily" or just enough to seem, well, flexible?
The district court ruled that the attachment element of the patent claim called for the thingy to connect only to the outside of the device, making the Sony game controller non-infringing. The court also ruled that a game-player's inability to bend the Sony controller "with ease" also supported the ruling against the inventor.
The Federal Circuit reversed. It held that the term "attached" could mean not only connection to an external surface but also touching a purely internal plane. The panel also ruled that "flexible" might include things we humans might find hard to bend. Thorner v. Sony Computer Entertainment Am. LLC, No. 11-0114 (Fed. Cir. Feb. 1, 2012).
The case well captures the rule that the normal meaning of words in patent claims almost always determines their scope. The rule doesn't apply only if (1) the patent itself explicitly redefines the words to mean something different (e.g., "black shall mean white") or explicitly disavows the normal meaning to U.S. Patent and Trademark Office.