How Intermittent Windshield Wipers Work
Robert Kearns' 1967 patent for the first electronic intermittent windshield wiper system that mimics the human eye's blinking motion.
Original patent title: “Windshield wiper system with intermittent operation”
Robert Kearns' 1967 patent for the first electronic intermittent windshield wiper system that mimics the human eye's blinking motion. Granted to TANN CO in 1967 with 2 claims and 23 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
This patent describes an electronic control circuit for windshield wipers that introduces a pause between each wipe. It uses a transistor to act as a switch that cuts power to the wiper motor at the end of a cycle. A capacitive timing circuit then holds the motor off for a set duration before triggering the next cycle. A mechanical switch linked to the motor's position ensures the wipers always return to the bottom of the windshield before the pause begins.
The gap
What does this patent NOT cover?
- Does not cover purely mechanical or vacuum-based intermittent wiper systems.
- Does not cover systems that adjust wipe speed based on rain sensors or optical detection.
- Does not cover continuous-speed wiper systems that lack a dwell period.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The innovation lies in using a capacitor to create a variable time delay that controls a transistor, allowing the motor to 'rest' at the bottom of its arc rather than running continuously.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Standard intermittent wiper settings on almost every car manufactured since the 1970s.
The 'delay' setting on automotive wiper stalks.
Why it matters
The bigger picture
This invention solved the problem of driving in light rain, where constant wiping creates annoying noise and smears the windshield. It became the subject of one of the most famous patent infringementinfringementMaking, using, selling, or importing a patented invention without permission from the patent holder.Read more → cases in history, pitting the inventorinventorThe person who actually conceived the invention. Listed on the patent regardless of who owns it.Read more →, Robert Kearns, against major automotive manufacturers who adopted his technology without licensing it.
Filed
December 1, 1964
Granted
November 7, 1967
Market context
Who's building on this
Companies in this space
The automotive industry at large adopted this fundamental logic. While the original patent has long expired, modern manufacturers like Ford, Toyota, and Volkswagen have evolved this into complex rain-sensing systems that build upon the basic timing logic established here.
Market impact
This patent effectively created the standard for modern windshield wiper operation. It triggered high-profile litigationlitigationA lawsuit over patent infringement. Litigated patents often signal commercial importance.Read more → that highlighted the challenges independent inventors face when dealing with large corporations, eventually leading to significant legal precedents regarding patent enforcement.
Claim 1 — Plain English
What this patent covers
This patent describes an electronic control circuit for windshield wipers that introduces a pause between each wipe. It uses a transistor to act as a switch that cuts power to the wiper motor at the end of a cycle. A capacitive timing circuit then holds the motor off for a set duration before triggering the next cycle. A mechanical switch linked to the motor's position ensures the wipers always return to the bottom of the windshield before the pause begins.
The clever bit
The innovation lies in using a capacitor to create a variable time delay that controls a transistor, allowing the motor to 'rest' at the bottom of its arc rather than running continuously.
What it does not cover
- Does not cover purely mechanical or vacuum-based intermittent wiper systems.
- Does not cover systems that adjust wipe speed based on rain sensors or optical detection.
- Does not cover continuous-speed wiper systems that lack a dwell period.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Early stage
Citation count
28/40
Moderately cited
Claim breadth
1/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$8K – $26K
Midpoint $16K · expired or expiring · industry ×0.9
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Patent Claims
1 independent claim · 0 dependent
Claims are the legal boundaries of the patent. An independent claim stands alone. A dependent claim adds limitations to its parent, narrowing — but not broadening — the scope.
The original legal language
Original claims
2 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Kearns, R. W. (1967). How Intermittent Windshield Wipers Work (U.S. Patent No. 3,351,836). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/3351836/intermittent-windshield-wiper-kearns
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Intermittent Windshield Wipers Work cover?
Robert Kearns' 1967 patent for the first electronic intermittent windshield wiper system that mimics the human eye's blinking motion.
Who owns patent US 3351836?
TANN CO owns this patent, granted in 1967.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 3351836 cited by?
This patent has been cited by 23 later patents that build on its ideas.
What problem does this patent solve?
This invention solved the problem of driving in light rain, where constant wiping creates annoying noise and smears the windshield. It became the subject of one of the most famous patent infringement cases in history, pitting the inventor, Robert Kearns, against major automotive manufacturers who adopted his technology without licensing it.
What does this patent NOT cover?
Does not cover purely mechanical or vacuum-based intermittent wiper systems.
Patent monitoring