Hotchkiss v. Greenwood: The Doorknob Case That Invented Nonobviousness

Hotchkiss v. Greenwood, 52 U.S. (11 How.) 248 (1850), is where American patent law first insisted that a valid patent requires something more than a new and useful thing. The invention was humble: a doorknob made of clay or porcelain rather than metal or wood, attached to its shank by a fastening method already well known. The Supreme Court held the patent void, reasoning that swapping in a better material by a known method called for no more ingenuity than an ordinary mechanic would bring to the task. That single idea, that patentability demands a degree of skill and ingenuity beyond the ordinary, became the seed of the modern nonobviousness requirement, later refined in Graham v. John Deere Co., 383 U.S. 1 (1966), and codified by Congress as 35 U.S.C. Section 103.

At a glance

• Case: Hotchkiss v. Greenwood, 52 U.S. (11 How.) 248 (1850)
• Court: Supreme Court of the United States (December 1850 Term)
• Holding: A patent that merely substitutes a known superior material into an existing article, using a known method of manufacture, is void for want of invention if the change required no more skill than that of an ordinary mechanic acquainted with the business
• Significance: The judicial origin of the nonobviousness requirement; foundation for Graham v. John Deere and 35 U.S.C. Section 103.

The invention and the dispute

The patentees, Hotchkiss and his co-inventors, held a patent on an improvement in making doorknobs. Their improvement was to make the knob from clay or porcelain instead of the metal or wood commonly used, and to attach it to a metal shank or spindle. Clay and porcelain knobs were attractive: they could be cheaper and more durable in some respects. The method of attaching the knob to the shank, using a dovetailed cavity and a screw or shank set into the knob, was not itself new. The same mode of fastening had been used to attach metallic and wooden knobs. The novelty the patentees claimed lay essentially in the choice of clay or porcelain as the knob material within that known structure.

Greenwood, sued for infringement, argued that this was no invention at all. Substituting one known material for another, where the manner of manufacture and attachment was already known, was the kind of thing any competent craftsman would do. The trial court instructed the jury that if the knob was new only in the sense that clay or porcelain had been substituted for metal or wood, and if attaching it required no more ingenuity than that of an ordinary mechanic, the patent was void. The jury found for Greenwood, and the patentees took the instruction to the Supreme Court.

Why novelty and utility were not enough

The patent statutes of the era required an invention to be new and useful. The clay knob was, in a literal sense, new: no one had patented that exact article before. It was useful. On the face of the statute, then, one might have expected the patent to stand. The conceptual leap of Hotchkiss was to hold that novelty and utility, standing alone, do not entitle an applicant to a patent. There must also be invention.

Justice Nelson, writing for the Court, upheld the jury instruction. The Court reasoned that the substitution of clay or porcelain for wood or metal, in a knob made by a known process and attached in a known way, produced at most a better or cheaper article. But an improved article is not the same as an invention. Unless more ingenuity and skill were required to make or apply the substitution than were possessed by “an ordinary mechanic acquainted with the business,” the Court held, “there was an absence of that degree of skill and ingenuity which constitute essential elements of every invention.” In other words, the work of a skilled artisan doing the expected thing is not patentable, however novel and useful the immediate result.

The “ordinary mechanic” standard

The phrase that carried the case into history is the “ordinary mechanic.” By measuring the claimed advance against what an ordinary mechanic acquainted with the business could do, the Court created a benchmark of ordinary skill against which every claimed invention would be tested. If the difference between the prior art and the claimed article was one the ordinary mechanic would supply as a matter of course, no patent could issue. That comparison, prior art on one side, the ordinary skilled worker in the middle, and the claimed advance measured against both, is the intellectual structure of nonobviousness. A century later, in Graham v. John Deere Co., the Supreme Court would restate the inquiry in almost the same terms, directing courts to determine the scope of the prior art, the differences between it and the claims, and the level of ordinary skill in the art. The “ordinary mechanic” of 1850 became the “person having ordinary skill in the art” of modern doctrine.

From judicial doctrine to statute

For a century after Hotchkiss, courts applied the “invention” requirement without a statutory anchor, and the standard grew unstable. Some decisions, most notoriously Cuno Engineering Corp. v. Automatic Devices Corp., 314 U.S. 84 (1941), suggested an invention must reveal a “flash of creative genius,” a phrase that seemed to demand something almost mystical and that made patents harder to sustain. The uncertainty fed a widespread sense that “the only patent that is valid is one which this Court has not been able to get its hands on,” as Justice Jackson later put it, dissenting in Jungersen v. Ostby & Barton Co., 335 U.S. 560, 572 (1949).

Congress responded in the Patent Act of 1952 by enacting Section 103, which for the first time set out nonobviousness as a statutory condition of patentability and directed that patentability “shall not be negatived by the manner in which the invention was made,” burying the “flash of genius” test. When the Supreme Court construed the new statute in Graham, it confirmed that Section 103 was intended to codify the Hotchkiss condition, not to change it. Hotchkiss thus supplies the direct doctrinal lineage from an 1850 doorknob to the obviousness analysis courts and examiners run every day.

Open questions

Hotchkiss announced a standard but not a method for applying it, and that gap has never fully closed. How does a court reliably decide what an “ordinary mechanic,” or today a person of ordinary skill, would find routine, without sliding into hindsight that treats every invention as obvious once explained? The Supreme Court addressed the danger of rigid tests in KSR International Co. v. Teleflex Inc., 550 U.S. 398 (2007), which loosened the Federal Circuit’s teaching-suggestion-motivation approach and reaffirmed a flexible, Graham-based inquiry. Yet the fundamental tension Hotchkiss opened, between rewarding genuine advances and denying patents for the predictable work of skilled artisans, remains the central difficulty of obviousness law as of July 2026.

Implications for inventors and businesses

• Novelty is necessary but not sufficient. A product can be new and useful and still unpatentable. The claimed advance must go beyond what a person of ordinary skill would do as a matter of course.
• Material or component substitutions are vulnerable. Simply swapping a known better material into an existing design, using known methods, invites an obviousness rejection or invalidity finding. Look for an unexpected result or a nonroutine adaptation.
• Document what the ordinary skilled worker would not have done. Evidence that the advance solved a problem others had missed, produced unexpected benefits, or overcame a technical hurdle helps rebut the charge that it was ordinary skill at work.
• The standard is old and durable. Because Hotchkiss underlies Section 103, its logic governs prosecution and litigation alike. Building a patent portfolio means building a record that the claimed inventions clear the ordinary-skill bar.

Frequently asked questions

What did the Hotchkiss patent claim? It claimed doorknobs made of clay or porcelain attached to a metal shank using a known dovetailing method previously used for metal and wooden knobs. The only change was substituting clay or porcelain for the older knob materials.

Why did the Supreme Court invalidate the patent? The Court held that merely substituting a better-known material, using an otherwise known method of attachment, required no more skill or ingenuity than that of an ordinary mechanic. Absent that degree of skill and ingenuity, there was no invention, and the patent was void.

How does Hotchkiss connect to modern obviousness law? Hotchkiss originated the requirement, beyond novelty and utility, of a threshold of ‘invention.’ The Supreme Court built on it in Graham v. John Deere, and Congress codified the concept as the nonobviousness requirement of 35 U.S.C. Section 103 in the 1952 Patent Act.

Authorities and sources

• Hotchkiss v. Greenwood, 52 U.S. (11 How.) 248 (1850). Full-text opinion via Cornell LII.
• 35 U.S.C. Section 103 (nonobviousness).
• Graham v. John Deere Co., 383 U.S. 1 (1966); Cuno Engineering Corp. v. Automatic Devices Corp., 314 U.S. 84 (1941); Jungersen v. Ostby & Barton Co., 335 U.S. 560 (1949); KSR International Co. v. Teleflex Inc., 550 U.S. 398 (2007).
• Casebriefs, “Hotchkiss v. Greenwood”.