## Facts

- Edward J. Schulenburg, Sr. acquired and operated a flasher-manufacturing business in Illinois (Time-O-Matic), developing sign flasher devices over many years.
- Time-O-Matic generated extensive internal engineering documentation, including thousands of drawings, blueprints, specifications, and circuit information used to refine its flashers.
- Key employees with long tenure and access to this technical material left Time-O-Matic, including J.W. Sutphin (who organized Signatrol, Inc.) and another employee who joined the new company.
- Signatrol began manufacturing and selling competing flashers.
- Plaintiffs alleged defendants used Time-O-Matic’s confidential drawings and related technical data to create Signatrol’s products, giving Signatrol a development “head start.”
- Trial-level factfinding credited evidence of copying, including substantial similarity in the content and layout of defendants’ drawings compared to plaintiffs’ documentation.
- Defendants contended the information was not protectable because competitors could lawfully determine flasher design by inspecting and analyzing the products (reverse engineering) and because the alleged secrets were general skill and knowledge.

## Issues

1. Whether plaintiffs’ engineering drawings, designs, and related technical information qualified as protectable trade secrets.
2. Whether defendants, as former employees and their new corporation, misappropriated plaintiffs’ trade secrets in designing and selling competing flashers.
3. Whether the injunction barring defendants’ manufacture and sale of competing flashers was overbroad in scope or duration.

## Decision

- The court held that certain aspects of plaintiffs’ flasher documentation and design information constituted trade secrets and that defendants’ conduct amounted to misappropriation and unfair competition.
- The court concluded the injunction as entered was overly broad because it risked granting plaintiffs ongoing control over competition, including competition based on lawful means (such as independent development or reverse engineering where feasible).
- The judgment was affirmed as to liability but reversed in part as to relief, and the cause was remanded with directions to modify the injunction to protect only genuine trade secrets and only for an appropriate period.

## Legal Principles

- Technical information may be a trade secret when it is not generally known or readily ascertainable by proper means, provides competitive advantage, and is subject to reasonable secrecy measures.
- Former employees may use general skill, experience, and knowledge gained during employment, but may not use or copy confidential plans, drawings, specifications, or other secret technical data to compete.
- Trade-secret law does not authorize a perpetual restraint on competition where product features can be discovered by lawful inspection or reverse engineering; relief must not operate as an improper monopoly.
- Injunctive relief should be tailored to eliminate the unfair advantage from misappropriation, including limiting scope to the specific secret information and limiting duration to the time reasonably needed to neutralize any “head start.”

## Conclusion

The Illinois Supreme Court treated the misuse of an employer’s confidential engineering documentation by departing employees as trade-secret misappropriation, but required a narrowed, time-limited injunction calibrated to remove the unfair competitive advantage without barring lawful competition.


Schulenburg v. Signatrol, Inc., 212 N.E.2d 865 (Ill. 1965)