Leonarde Keeler's Early Mechanical Blood Pressure Recorder
A 1925 invention by Leonarde Keeler designed to mechanically record a patient's arterial blood pressure over time.
Original patent title: “Apparatus for recording arterial blood pressure”
A 1925 invention by Leonarde Keeler designed to mechanically record a patient's arterial blood pressure over time. Granted to Individual in 1931 with 4 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
The device functions as a specialized mechanical apparatus for monitoring and documenting arterial blood pressure. It uses a pressure-sensitive mechanism to track fluctuations in a patient's pulse and blood flow. By translating these physical movements into a readable format, it allows clinicians to observe changes in pressure without constant manual observation.
The gap
What does this patent NOT cover?
- Does not cover electronic or digital blood pressure sensors.
- Does not cover automated cuff inflation systems found in modern monitors.
- Does not cover methods for analyzing blood pressure data using software or algorithms.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The invention focuses on the mechanical translation of arterial pulses into a physical record, removing the need for a human to manually chart every point of pressure change in real-time.
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 sphygmograph prototypes
Analog clinical patient monitoring equipment
Why it matters
The bigger picture
This patent represents an early effort to move clinical diagnostics from subjective manual measurements to objective, recorded data. It highlights the transition toward continuous patient monitoring in medical settings.
Filed
July 30, 1925
Granted
January 13, 1931
Market context
Who's building on this
Companies in this space
Modern medical device manufacturers like Omron and Welch Allyn have evolved these early mechanical concepts into highly sophisticated digital diagnostic tools used in hospitals worldwide.
Market impact
This patent contributed to the early standardization of clinical monitoring, helping shift medical practice toward the use of recorded data for long-term patient health assessment.
Claim 1 — Plain English
What this patent covers
The device functions as a specialized mechanical apparatus for monitoring and documenting arterial blood pressure. It uses a pressure-sensitive mechanism to track fluctuations in a patient's pulse and blood flow. By translating these physical movements into a readable format, it allows clinicians to observe changes in pressure without constant manual observation.
The clever bit
The invention focuses on the mechanical translation of arterial pulses into a physical record, removing the need for a human to manually chart every point of pressure change in real-time.
What it does not cover
- Does not cover electronic or digital blood pressure sensors.
- Does not cover automated cuff inflation systems found in modern monitors.
- Does not cover methods for analyzing blood pressure data using software or algorithms.
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
Limited data
Citation count
14/40
Early citations
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
$7K – $21K
Midpoint $13K · expired or expiring · industry ×2.2
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
Concepts involved
Citations
Patent lineage
Cite this patent
Leonarde, K. (1931). Leonarde Keeler's Early Mechanical Blood Pressure Recorder (U.S. Patent No. 1,788,434). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/1788434/polygraph-lie-detector-keeler
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 Leonarde Keeler's Early Mechanical Blood Pressure Recorder cover?
A 1925 invention by Leonarde Keeler designed to mechanically record a patient's arterial blood pressure over time.
Who owns patent US 1788434?
Individual owns this patent, granted in 1931.
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 1788434 cited by?
This patent has been cited by 4 later patents that build on its ideas.
What problem does this patent solve?
This patent represents an early effort to move clinical diagnostics from subjective manual measurements to objective, recorded data. It highlights the transition toward continuous patient monitoring in medical settings.
What does this patent NOT cover?
Does not cover electronic or digital blood pressure sensors.
Same assignee
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