Talk:Hotchkiss v. Greenwood, 52 U.S. 11 (1850)
A patent granted for a "new and useful improvement in making door and other knobs of all kinds of clay used in pottery, and of porcelain" by 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" was invalid.
The test was that if no more ingenuity and skill was necessary to construct the new knob than was possessed by an ordinary mechanic acquainted with the business, the patent was void, and this was a proper question for the jury.
In October, 1845, the plaintiffs in error brought an action in the Circuit Court of the United States for Ohio, against the defendants, for a violation of the patent right.
The following bill of exceptions was taken during the trial:
"The plaintiffs offered in evidence the patent specifications and drawings, and other evidence, tending to prove the originality, novelty, and usefulness of the inventions as described in said specification; and other evidence, tending to show the violation of said patent by the defendant, and rested. Whereupon the defendants offered evidence tending to show that the said alleged invention was not originally invented by anyone of the said patentees; and that if said invention was original with any of the said patentees, it was not the joint invention of all of said patentees; and other evidence, tending to show that the mode of fastening the shank or collet to the knob, adopted by the plaintiffs, and in said specification described, had been known and used in Middletown, Connecticut, prior to the alleged inventions of the plaintiffs, as a mode of fastening shanks or collets to metallic knobs. And the evidence being closed, the counsel for the plaintiffs insisted in the argument, that, although the knob, in the form in which it is patented, may have been known and used in the United States prior to their invention and patent; and although the shank and spindle, by which it is attached, may have been known and used in the United States prior to said invention and patent, yet if such shank and spindle had never before been attached to a knob made of potter's clay or porcelain, and if it required skill and thought and invention to attach the said knob of clay to the metal shank and spindle, so that the same would unite firmly, and make a solid and substantial article of manufacture, and if the said knob of clay or porcelain so attached were an article better and cheaper than the knob theretofore manufactured of metal or other materials, that the patent was valid, and asked the court so to instruct the jury, which the court refused to do; but, on the contrary thereof, instructed the jury, that if knobs of the same form, and for the same purposes with that described by the plaintiffs in their specifications, made of metal or other material, had been known and used in the United States prior to the alleged invention and patent of the plaintiffs, and if the spindle and shank, in the form used by the plaintiffs, had before that time been publicly known and used in the United States, and had been theretofore attached to metallic knobs by means of the dovetail and the infusions of melted metal, as the same is directed in the specification of the plaintiffs to be attached to the knob of potter's clay or porcelain, so that if the knob of clay or porcelain
Page 52 U. S. 253
is the mere substitution of one material for another, and the spindle and shank be such as were theretofore in common use, and the mode of connecting them to the knob by dovetail be the same that was theretofore in use in the United States, the material being in common use, and no other ingenuity or skill being necessary to construct the knob than that of an ordinary mechanic acquainted with the business, the patent is void, and the plaintiffs are not entitled to recover. The counsel for the defendants asked the court to instruct the jury that if they should be satisfied that anyone of the patentees was the original inventor of the article in question, and that the same was new and useful, yet if they should be satisfied from the evidence that all the patentees did not participate in the invention, the patent is void, and the plaintiffs cannot recover. The court gave the above, modified by the remark, that the patent was prima facie evidence that the invention was joint, though the fact might be disproved on the trial; and the court remarked, there was no evidence except that of a slight presumption against the joint invention as proved by the patent; to which refusal of the court to instruct the jury as asked by the counsel for the plaintiffs, and to the instructions given, the plaintiffs, by their counsel, except, and pray the court to sign this their bill of exceptions."