Schriber-Schroth Co. v. Cleveland Trust Co.
Headline: Patent on engine pistons limited: Court blocks expanding claims to cover 'flexible webs' surrendered during prosecution, making it harder for the patent holder to stop dealers from selling accused pistons.
Holding: The Court reversed the appeals court and held that Jardine's allowed patent claims cannot be read to include flexible webs that were surrendered during prosecution, and therefore the patent does not validly cover that inventive feature.
- Stops patentees from reclaiming features they surrendered in the patent office.
- Protects manufacturers and dealers from suits based on surrendered claim features.
- Requires applicants to keep explicit claim language when seeking broader protection.
Summary
Background
A bank-trust company that manages a large pool of piston patents sued three piston dealers who bought pistons from a manufacturer, accusing them of infringing several piston patents, including one by Jardine. The lower courts and a special master had disagreed about whether a feature called “flexible” or “yielding” webs was part of the patented invention and whether that feature made the patents new compared with earlier engine designs.
Reasoning
The central question was whether Jardine’s allowed patent claims could be read to include flexible webs when Jardine had earlier proposed and then withdrawn claims that explicitly described those flexible webs during patent-office proceedings. The Court explained that claims must be read in light of the patent file history. When an inventor cancels or surrenders claim language in the patent office, the allowed claims cannot later be stretched to recover that surrendered feature. Because Jardine had removed the flexible-web claims after the patent office rejected them, the Court would not treat the allowed claims as covering flexible webs.
Real world impact
The Court concluded that without the surrendered flexible-web feature the Jardine patent did not show invention over prior parts and could not be enforced as the court below had done. The decision protects manufacturers and dealers from being blocked by a patent that a holder tried to broaden after giving up specific claim language, and it reinforces that patent applicants must secure and keep the exact claim language they want to enforce.
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