In re Mahony

Posted by Unknown on Wednesday, March 22, 2006 with No comments


In re John P. Mahony (1970) 57 CCPA 939; 421 F.2d 742


US Court of Customs and Patent Appeals


Patent for circuits and methods for automatically synchronising a receiver of digital information. The invention specifically related to the way in which a receiving device could know where to divide a stream of bits into words, wherein each word consisted of a certain number of bits and a pattern of framing bits.


The CCPA overturned the rejection of the examiner, and its affirmation by the board.


  • The present case was distinguishable from Prater in that the language of the claims made it clear that protection of a machine-implemented process was sought. (per Stone J at 945)
  • The term "bit" when used in conjunction with "bit stream" has a meaning in the art which precludes reading the claims on a mentally performed process. (per Stone J at 945)


The case contains an implicit affirmation of the mental process doctrine, yet uses a narrow interpretation of that doctrine to avoid its application to avoid its application. Arguably a bad decision on the basis that it fails to consider that the only useful application of this mathematical process is in relation to digital networking (an early example of preemption of the algorithm).