In the case of The Baldwin Company et al. v. R.S. Howard Company, 1920, the U.S Supreme Court was asked to determine whether a patent held by The Baldwin Company for a specific type of piano action (the mechanism that produces sound in pianos) had been infringed upon by R.S Howard Co., who were manufacturing similar devices. The court found that while there were similarities between the two designs, they were not identical and therefore did not constitute an infringement on Baldwin's patent rights. Furthermore, it was determined that even if there had been direct copying involved, this would still not have constituted an infringement as long as no patented features were copied or used without permission from the original holder - in this case being The Baldwin Co.. This ruling helped clarify what constitutes patent infringement within American law.

In the dissenting opinion for The Baldwin Company et al. v. R.S. Howard Company, it was argued that the majority's decision to uphold a lower court ruling in favor of R.S. Howard Co., which had sued Baldwin Co. for patent infringement, was flawed due to an incorrect interpretation of patent law and precedent cases related to patents on improvements or modifications of existing inventions. The dissenting justices believed that while the defendant did use a similar mechanism as described in plaintiff’s patent, they used it differently and achieved different results; therefore, there should not be any infringement claim since this is within permissible limits under improvement/modification clause in Patent Law.