page_title: Hotchkiss v. Greenwood
section_title: Background
hierarchical_section_title: Hotchkiss v. Greenwood / Background
caption_attribution_description: English: This is the drawing from US Pat No 2197 that was involved in the case Hotchkiss v. Greenwood Other information This is the drawing for a US patent
context_page_description: Hotchkiss v. Greenwood, 52 U.S. 248, was a United States Supreme Court decision credited with introducing into United States patent law the concept of non-obviousness as a patentability requirement, as well as stating the applicable legal standard for determining its presence or absence in a claimed invention.
  The test of the Hotchkiss case may be described as: whether, at the time the claimed invention was made, the differences between the features of the claimed invention and the things that persons skilled in the relevant art already knew were such that it would have been within the level of skill of an ordinary artisan in that art to combine those known features to make the claimed invention.
  More specifically, as stated in the Hotchkiss opinion, itself:
  Unless more ingenuity and skill. .. were required. .. than were possessed by an ordinary mechanic acquainted with the business, there was an absence of that degree of skill and ingenuity which constitute essential elements of every invention. In other words, the improvement is the work of the skillful mechanic, not that of the inventor.
context_section_description: John G. Hotchkiss, John A. Davenport, and John W. Quincy obtained U.S. Patent No. 2197, on making or manufacturing knobs of potter's clay or porcelain. The patent asserted that they:
  invented an improved method of making knobs for locks, doors, cabinet furniture, and for all other purposes for which wood and metal, or other material knobs, are used. This improvement consists in making said knobs of potter's clay, such as is used in any species of pottery; also of porcelain; the operation is the same as in pottery, by molding, turning, and burning and glazing; . . . the modes of fitting them for their application to doors, locks, furniture, and other uses, will be . . . chiefly predicated on one principle, that of having the cavity in which the screw or shank is inserted, by which they are fastened, largest at the bottom of its depth, in form of a dovetail, and a screw formed therein by pouring in metal in a fused state.
  The clay or porcelain knob, by itself, was apparently known and used in the United States prior to the invention and patent, and the shank and spindle, by which the knob is attached, including the use of the dovetail and the infusions of melted metal, were also so known and used. But the shank and spindle, the inventors contended, had never before been attached to a knob made of potter's clay or porcelain (rather than to a metal or wooden knob).
caption: The patented doorknob – from U.S. Pat. No. 2197
exif: {}