View source for Tennant Case 5: Graham v. John Deere (1966)

The U. S. Supreme Court ruling on this case begins with an extended manifesto on the purpose of patent law and how patentability ought to be determined. It begins by saying that Congress has an explicit duty to issue patents, but is also bound in the same breath to granting patents only to those inventions which promote science and the useful arts. In his letters, Thomas Jefferson, an author of the Constitution, affirmed and endorsed this Congressional power in letters he wrote to James Madison. It is important to note that Jefferson did not view the monopoly granted to an inventor by a patent as a right; rather, it was a reward for bringing forth new knowledge into the world.

The ruling goes on to list several cases in which patentability, and in particular nonobviousness, were both at issue; several cases discussed previously were included in this listing. The main impact of this section is the establishment of a methodology by which one can determine whether an invention is patentable. The first determinations to be made are the scope and content of prior art, the difference between the prior art and the current claims, and the level of ordinary skill in the art closely related to the claims. Considerations such as commercial ability, the length and satisfaction of needs, or the success/failure of others are secondary qualifications of nonobviousness; they are not the first discourse to be undertaken in determining patentability.

This method is exercised in determining the patentability of the chisel plow design which incorporates a free shock-absorbing system to minimize damage due to rocky soil. Graham developed one plow which sought to reduce the wear due to rocky soil and patented it. He then developed a modification for the plow and patented it, as well; he then sued John Deere and others for infringement. The lower courts determined that the new patent was not an invention under Graham's claims because it required no extraordinary skill in the art. He then began to claim patentability under other features which were not previously mentioned in the patent application.

The Court found that the petitioners' arguments were unfounded and that there were no aspects of the patent which were nonobvious. The aspects of the patent which were considered to be inventions were in fact part of the body of prior art and thus were not new. The features which the petitioners claim as new do not in fact result in an advancement of the art; thus, the design is not an invention.