Hotchkiss v. Greenwood
11 How. 248 (1851)
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Rule of Law:
The substitution of a superior material for another in the manufacturing of a known article is not a patentable invention if the new combination does not require any more skill or ingenuity than that possessed by an ordinary mechanic acquainted with the business.
Facts:
- The patentees developed a method for making knobs for doors and furniture out of potter's clay or porcelain.
- Their process involved creating a knob with a dovetail-shaped cavity (largest at the bottom).
- A metal shank was inserted into this cavity.
- Melted metal was then poured into the cavity, which cooled and formed a screw, securely fastening the shank to the knob.
- Prior to this, knobs made of metal and wood were common.
- The method of using a dovetail cavity and fused metal to attach a shank to a knob was already known and used with metallic knobs.
- The use of potter's clay as a material was not new in itself.
Procedural Posture:
- The patentees (plaintiffs) sued the defendants for patent infringement in the Circuit Court of the United States for the District of Ohio.
- At trial, the plaintiffs' counsel asked the court to instruct the jury that the patent was valid if the new knob was a better and cheaper article that required skill to create.
- The trial court refused this instruction.
- The court instead instructed the jury that the patent was invalid if the knob's form, shank, and attachment method were all previously known, and the substitution of clay for other materials did not require more skill than that of an ordinary mechanic.
- The plaintiffs brought the case to the U.S. Supreme Court on a writ of error to challenge the trial court's jury instruction.
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Issue:
Does the application of a known manufacturing process to a different but known material, resulting in a superior and cheaper article, constitute a patentable invention?
Opinions:
Majority - Mr. Justice Nelson
No. The application of a known manufacturing process to a different but known material does not constitute a patentable invention if it does not require inventive skill. The novelty here consists merely in substituting a clay knob for a metal or wood one, using a pre-existing attachment method. While the resulting product may be better and cheaper, this superiority comes from the known qualities of the material itself, not from any new mechanical device or contrivance. This improvement is the work of a skillful mechanic, not that of an inventor, as it lacks the degree of skill and ingenuity that are essential elements of every invention.
Dissenting - Mr. Justice Woodbury
Yes. The proper test for whether an invention is patentable should be whether the resulting article is new, better, and cheaper than what preceded it. The majority's test—whether an 'ordinary mechanic' could have devised it—is an incorrect standard. An invention's value to the public in being better and cheaper is the key consideration, not the 'process of mind' or level of skill that led to its discovery. The law should protect and encourage such useful improvements that benefit the community, regardless of how simple or obvious they may seem in hindsight.
Analysis:
This case is foundational in U.S. patent law for establishing the principle of non-obviousness as a requirement for patentability, a doctrine later codified in 35 U.S.C. § 103. It creates a distinction between mere artisanship or mechanical skill and true inventive ingenuity. The decision raised the bar for obtaining a patent, requiring that an invention not only be new and useful but also represent a step forward that would not have been apparent to a person of ordinary skill in the relevant field. This 'Hotchkiss test' prevents patents on trivial improvements or simple substitutions of materials that lack an inventive leap.
