U.S. Patent No. 7,086,747, directed to energy efficient lighting retrofit.  In one embodiment, a housing with an attachment surface and opposite illumination surface is sized to be installed to an existing ballast cover (page 3). The claim recites “a fastening mechanism for securing the attachment surface of the lighting apparatus to the illumination surface” (pages 3-4).  The attachment surface is not a layer of the housing that is secured to the ballast cover, but is instead for attachment to the illumination surface (pages 4 and 5).  The fastener to the cover of the embodiment should not be read into the claim as there is no teaching in the specification of attachment to the cover be essential and/or part of the invention (pages 5-7).   In prosecution, the fastener to the ballast cover was removed from the claims (page 7).  The amendment was linked to a 112 rejection by the Examiner and the Applicant did not dispute this link during prosecution (pages 7-8).

Hindsight: Other options for amendment could have been explored, including using different amendments for different claims.  A more generic reference for the surface to which the attachment surface is fastened could have helped.  While arguing in prosecution that the amendment is not to overcome 112 may have helped, it does not seem likely the court would have found a different outcome.  Further confusion results from reciting the “ballast cover” in the preamble but then not including that ballast cover anywhere in the claim.  The preamble could have tied the cover to the body of the claim more clearly.