The Intermittent Wiper Patent War: How Robert Kearns Fought Detroit for 30 Years

On his wedding night in 1953, a champagne cork struck Robert Kearns in the left eye. The injury left him with impaired vision and, unexpectedly, an obsession. As Kearns recovered, he became fascinated by how the human eye blinks—not continuously, but intermittently—to keep itself clean and moist.

At the time, windshield wipers had only two speeds: low and high. Both were continuous. In light rain or mist, this was maddening—the blades would screech across semi-dry glass, leaving streaks and wearing prematurely. Kearns, an engineering professor at Wayne State University in Detroit, wondered: why couldn't wipers blink like an eye?

He spent over a decade developing the answer. In 1967, he was granted U.S. Patent No. 3,351,836 for a "Windshield Wiper System with Intermittent Operation." The invention would eventually appear on virtually every car in the world. But Kearns would have to fight for 30 years to receive credit—and compensation—for what he created.

The Invention

The Technical Innovation

Kearns's intermittent wiper circuit used a transistor, a capacitor, and a variable resistor to create an adjustable "dwell" period between wipe cycles. The capacitor would charge slowly, then discharge to trigger the wiper motor. By adjusting the resistor, the driver could control the delay—from a quick pause to several seconds between wipes.

Crucially, Kearns's design included an "automatic braking" feature that parked the wipers precisely at the bottom of the windshield after each cycle, regardless of where they were in the arc when the driver turned them off. This seemingly minor detail was a significant engineering achievement.

The Working Prototype

Kearns built a working prototype and installed it in his own car. The system worked flawlessly. He began approaching automakers, believing that his invention would be welcomed and that he would be compensated fairly for licensing it.

The Betrayal

The Ford Demonstration

In the late 1960s, Kearns demonstrated his intermittent wiper system to engineers at Ford Motor Company. According to court testimony, the Ford engineers were impressed. They asked detailed questions about the circuit design and requested that Kearns leave his prototype for further evaluation.

Kearns believed he was negotiating a licensing deal. Instead, after a prolonged period of evaluation, Ford ceased contact. In 1969, Ford introduced its own intermittent wiper feature on the Mercury line. The company claimed it was developed in-house.

The Industry Follows

Chrysler and other automakers soon introduced their own intermittent wiper systems. By the mid-1970s, the feature was becoming standard across the industry. None of these companies paid Kearns a licensing fee or acknowledged his patent.

The Legal Battle

David vs. Goliath

Kearns filed patent infringement lawsuits against Ford and Chrysler. He faced a seemingly impossible challenge: a lone inventor against two of the world's largest corporations, each with unlimited legal resources and armies of patent attorneys.

The automakers' defense strategy centered on the concept of "non-obviousness"—a requirement for patent validity. They argued that Kearns had merely assembled off-the-shelf electronic components (transistors, capacitors, resistors) in a way that any competent engineer could have devised. Therefore, they claimed, the patent was invalid.

The Synergistic Effect Argument

Kearns's counter-argument became a landmark in patent law. He argued that, like a novel composed of common words or a symphony composed of standard notes, his specific arrangement of components created something new and non-obvious. The individual parts were public domain, but the synergistic effect of their arrangement was uniquely his invention.

This "synergistic effect" doctrine would influence patent law for decades, establishing that inventions combining known elements can still be patentable if the combination produces unexpected or superior results.

The Personal Cost

The litigation consumed Kearns's life. He insisted on representing himself for significant portions of the case, believing that no attorney could understand the technical details as well as he could. The stress led to a nervous breakdown and hospitalization.

His marriage ended. His relationships with his children were strained. For nearly three decades, the lawsuit was his singular obsession—a quest for recognition that most people around him believed was futile.

But Kearns persisted. He rejected multiple settlement offers that would have provided financial compensation but required him to drop his claims of inventorship. For Kearns, the money was secondary; he wanted Ford and Chrysler to acknowledge publicly that they had stolen his invention.

The Verdicts

Ford: $10.1 Million (1990)

In 1990, after years of litigation, Ford agreed to settle with Kearns for approximately $10.1 million. The settlement came before a final verdict, but it represented a significant vindication.

Chrysler: $18.7 Million (1995)

The Chrysler case went to a jury verdict. In 1995, Kearns was awarded $18.7 million in damages, plus interest—totaling nearly $30 million when combined with the Ford settlement. The jury found that Chrysler had willfully infringed Kearns's patent.

Kearns had won. But he had spent 30 years of his life—and sacrificed his marriage and mental health—to achieve a victory that the automakers could have avoided with a fair licensing agreement decades earlier.

Legacy

Patent Law Impact

The Kearns case remains a cornerstone of patent law education. It established important precedents about the patentability of combinations of known elements and demonstrated that individual inventors can prevail against corporate giants—though at enormous personal cost.

Cultural Recognition

Kearns's story was dramatized in the 2008 film "Flash of Genius," starring Greg Kinnear. The film brought his decades-long struggle to a wider audience and raised awareness about the challenges independent inventors face when challenging industrial incumbents.

The Technology Today

Intermittent wipers are now standard on virtually every vehicle sold worldwide. Modern systems have evolved to include rain-sensing automatic activation, but they all trace their lineage to Kearns's 1967 patent—the invention a champagne cork inspired.

Robert Kearns died in 2005, having finally received recognition for his contribution to automotive safety. Every time you adjust your wiper delay in a light rain, you're using his invention.

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