How Laurens Hammond Invented the Electric Organ
Laurens Hammond's 1934 patent for an electrical musical instrument that used spinning tone wheels to generate sound, forming the basis of the iconic Hammond organ.
Original patent title: “Electrical musical instrument”
Laurens Hammond's 1934 patent for an electrical musical instrument that used spinning tone wheels to generate sound, forming the basis of the iconic Hammond organ. Granted to Individual in 1934 with 35 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
The patent describes a system for generating musical tones using rotating electromagnetic tone wheels. As these metallic wheels spin near electromagnetic pickups, they create alternating currents that correspond to specific musical frequencies. These signals are then amplified and sent to a speaker to produce sound, effectively replacing the heavy pipes and air-driven bellows of traditional organs with compact electronic components.
The gap
What does this patent NOT cover?
- Does not cover digital synthesis or software-based sound generation.
- Does not cover modern MIDI-based keyboard controllers.
- Does not cover instruments that rely on vibrating strings or reeds.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
By using precise electromagnetic induction from spinning wheels, Hammond turned mechanical motion into a pure, controllable electrical signal, bypassing the need for physical air columns.
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
Hammond B3 Organ
Hammond C3 Organ
Vintage electric organs used in classic rock and soul music
Why it matters
The bigger picture
This invention allowed churches and venues to have the rich, powerful sound of a pipe organ without the massive cost and physical space requirements. It became the backbone of jazz, blues, and rock music for decades, defining the sound of the 20th century.
Filed
January 19, 1934
Granted
April 24, 1934
Market context
Who's building on this
Companies in this space
The Hammond Organ Company established a legacy that modern digital keyboard manufacturers like Nord, Roland, and Yamaha continue to emulate through high-fidelity digital modeling of these original electromagnetic circuits.
Market impact
This patent enabled the creation of an entirely new category of portable, affordable, and reliable musical instruments, effectively democratizing access to organ music outside of large cathedrals.
Claim 1 — Plain English
What this patent covers
The patent describes a system for generating musical tones using rotating electromagnetic tone wheels. As these metallic wheels spin near electromagnetic pickups, they create alternating currents that correspond to specific musical frequencies. These signals are then amplified and sent to a speaker to produce sound, effectively replacing the heavy pipes and air-driven bellows of traditional organs with compact electronic components.
The clever bit
By using precise electromagnetic induction from spinning wheels, Hammond turned mechanical motion into a pure, controllable electrical signal, bypassing the need for physical air columns.
What it does not cover
- Does not cover digital synthesis or software-based sound generation.
- Does not cover modern MIDI-based keyboard controllers.
- Does not cover instruments that rely on vibrating strings or reeds.
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
31/40
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 – $46K
Midpoint $29K · expired or expiring · industry ×1.6
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
Laurens, H. (1934). How Laurens Hammond Invented the Electric Organ (U.S. Patent No. 1,956,350). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/1956350/hammond-organ
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 Laurens Hammond Invented the Electric Organ cover?
Laurens Hammond's 1934 patent for an electrical musical instrument that used spinning tone wheels to generate sound, forming the basis of the iconic Hammond organ.
Who owns patent US 1956350?
Individual owns this patent, granted in 1934.
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 1956350 cited by?
This patent has been cited by 35 later patents that build on its ideas.
What problem does this patent solve?
This invention allowed churches and venues to have the rich, powerful sound of a pipe organ without the massive cost and physical space requirements. It became the backbone of jazz, blues, and rock music for decades, defining the sound of the 20th century.
What does this patent NOT cover?
Does not cover digital synthesis or software-based sound generation.
Same assignee
More from Individual
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