Ensten v. Simon, Ascher & Co.
Headline: Court affirms that a patent owner’s nearly two-year delay in disclaiming an invalid knitted-cap claim is unreasonable, blocking his injunction and damages and making it harder to enforce that patent against makers.
Holding: The Court held that the inventor unreasonably delayed nearly two years to disclaim a previously invalidated patent claim, so he forfeited the statute’s protections and the courts rightly denied an injunction and damages.
- Requires inventors to promptly disclaim or appeal after an adverse ruling, or lose enforcement rights.
- Allows manufacturers to continue making products if the patent owner delays disclaiming invalid claims.
- Limits damage recovery and injunctions for patentees who wait too long to correct mistakes.
Summary
Background
An inventor of an improved knitted cap held a patent with six claims. A federal judge in Ohio declared one of those claims (claim 2) invalid in an interlocutory ruling on May 24, 1922. The inventor waited until April 30, 1924 to file a formal disclaimer of that invalid claim, while continuing to assert the claimed monopoly and seek relief in court against a company accused of infringement.
Reasoning
The central question was whether that delay was “unreasonable” under the statute that lets an inventor correct an honest mistake by disclaiming parts of a patent. The Court explained that the law allows relief only when an inventor acts in good faith and promptly either appeals an adverse ruling or files a disclaimer. Because the inventor could have appealed within thirty days or otherwise sought a quick decision but instead held the rejected claim for nearly two years, the Court concluded he failed to act promptly and therefore lost the special protections of the disclaimer rules. The Court affirmed the lower courts’ denial of an injunction and dismissal of the suit.
Real world impact
Patent owners must either promptly challenge an adverse court ruling or promptly disclaim an invalid claim, or they risk losing the ability to recover damages or get an injunction. The decision protects manufacturers and competitors from long delays in which a patent holder asserts an apparent monopoly while a claim’s validity remains unresolved. This opinion resolves the question in favor of prompt action to correct mistaken claims.
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