Ralph Teetor's Speed Control Device for Automobiles
A 1948 invention by Ralph Teetor that introduced the mechanical foundation for modern cruise control by creating a system to resist accelerator pedal movement at a set speed.
Original patent title: “Speed control device for resisting operation of the accelerator”
A 1948 invention by Ralph Teetor that introduced the mechanical foundation for modern cruise control by creating a system to resist accelerator pedal movement at a set speed. Granted to Individual in 1950 with 23 forward citations, and it is now in the public domain.
Key facts
Coverage
What does this patent actually cover?
The device acts as a mechanical governor for an automobile's accelerator pedal. It uses a speed-sensing mechanism connected to the vehicle's drivetrain to monitor velocity. When the car reaches a pre-selected speed, the device engages a resistance mechanism that pushes back against the driver's foot on the gas pedal. This provides tactile feedback to the driver, effectively signaling or maintaining a constant speed by making it physically difficult to accelerate further without intentional effort.
The gap
What does this patent NOT cover?
- Does not cover fully electronic drive-by-wire throttle systems.
- Does not cover automatic braking or collision avoidance systems.
- Does not cover systems that maintain speed without providing physical feedback to the pedal.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The innovation lies in using the accelerator pedal itself as a communication interface, providing tactile feedback to the driver rather than just disconnecting the throttle.
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
Early mechanical cruise control systems in 1950s and 60s Chrysler vehicles
Speedostat systems
Why it matters
The bigger picture
This invention is the direct ancestor of modern cruise control. Ralph Teetor, who was blind, was inspired to invent the system after experiencing the frustration of his driver constantly slowing down and speeding up while talking. It transformed long-distance driving by reducing driver fatigue.
Filed
August 11, 1948
Granted
August 22, 1950
Market context
Who's building on this
Companies in this space
Major automotive suppliers like Bosch and Continental have evolved these mechanical principles into sophisticated electronic cruise control and adaptive cruise control systems used by virtually every global automaker today.
Market impact
This patent laid the groundwork for the cruise control feature, which became a standard expectation for consumer vehicles in the United States by the 1960s. It shifted the automotive market toward prioritizing driver comfort and long-distance convenience as a key selling point.
Claim 1 — Plain English
What this patent covers
The device acts as a mechanical governor for an automobile's accelerator pedal. It uses a speed-sensing mechanism connected to the vehicle's drivetrain to monitor velocity. When the car reaches a pre-selected speed, the device engages a resistance mechanism that pushes back against the driver's foot on the gas pedal. This provides tactile feedback to the driver, effectively signaling or maintaining a constant speed by making it physically difficult to accelerate further without intentional effort.
The clever bit
The innovation lies in using the accelerator pedal itself as a communication interface, providing tactile feedback to the driver rather than just disconnecting the throttle.
What it does not cover
- Does not cover fully electronic drive-by-wire throttle systems.
- Does not cover automatic braking or collision avoidance systems.
- Does not cover systems that maintain speed without providing physical feedback to the pedal.
Patent Journey
From filing to expiry
PatentBrief Score
Impact Score
Early stage
Citation count
28/40
Moderately cited
Claim breadth
0/20
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
$14K – $43K
Midpoint $27K · expired or expiring · industry ×1.5
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Concepts involved
Citations
Patent lineage
Cite this patent
Teetor, R. R. (1950). Ralph Teetor's Speed Control Device for Automobiles (U.S. Patent No. 2,519,859). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/2519859/cruise-control-teetor
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 Ralph Teetor's Speed Control Device for Automobiles cover?
A 1948 invention by Ralph Teetor that introduced the mechanical foundation for modern cruise control by creating a system to resist accelerator pedal movement at a set speed.
Who owns patent US 2519859?
Individual owns this patent, granted in 1950.
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 2519859 cited by?
This patent has been cited by 23 later patents that build on its ideas.
What problem does this patent solve?
This invention is the direct ancestor of modern cruise control. Ralph Teetor, who was blind, was inspired to invent the system after experiencing the frustration of his driver constantly slowing down and speeding up while talking. It transformed long-distance driving by reducing driver fatigue.
What does this patent NOT cover?
Does not cover fully electronic drive-by-wire throttle systems.
Same assignee
More from Individual
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