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If you really want to know about the technology of the Hammond organ, the best place to get a true understanding about how the organ works is to read the patents. Here is a somewhat exhausting list of Hammond patents related to musical instruments. You'll find a lot of information in the patents about concepts like LoudnessRobbing, KeyClick, etc. that really explains what is going on. There are also some patents listed here that were never used on any tonewheel Hammond organ. Here are a few of the patents issued to LaurensHammond and Hammond Organ Company engineers JohnHanert, Gilbert Smiley, W J Wehermann, Herbert Meinema, George Stephens and Thomas George:
Year Number Inventor(s) Title/Description
1921 1,435,520 Hammond Stereoscopic Motion Picture (3d movies!)
1929 1,719,805 Hammond Alternating Current Clock.
1934 1,956,350 Hammond Electrical Musical Instrument (original organ patent).
1936 2,036,892***Smiley Art of Producing Musical Sounds Electronically (RE20825).
1936 2,083,246***Smiley Electronic Musical Instrument(RE20831).
1937 2,099,204 Hammond Multiple Key Switch (keyboard switch contacts).
1938 2,117,002* Hammond Keyboard for Musical Instruments (keyboard construction).
1938 2,126,464***Hammond Electrical Musical Instrument (Touch sensitive circuit).
1938 2,126,682***Hammond Electrical Musical Instrument (Tube frequency divider).
1939 2,159,505 Hammond Electric Organ (chorus generator).
1939 2,161,706 Hammond Electrical Musical Instrument (Delay circuit).
1939 2,173,888 Smiley Electronic Musical Instrument (Grid-bias keying).
1939 2,184,424 Hammond Electrical Musical Instrument (Keyboard construction).
1940 2,199,702 Hammond Method of Broadcasting (Radio studio organ miking).
1940 2,203,432 George, Hammond Electrical Musical Instrument (6 oscillators).
1940 2,203,569 Hammond Musical Instrument (Solovox).
1940 2,216,513 Hammond Electrical Musical Instrument (Slow decay with capacitors).
1940 2,211,205 Hammond Reverberation Apparatus (Shipping lock for 2,230,836).
1940 2,214,764 Hammond Electrical Musical Instrument (Electrostatic tone generator).
1940 2,221,188 Hammond Electrical Musical Instrument (Swell and tremulant circuit).
1940 2,224,729 Hammond Electrical Musical Instrument (Improved grid-bias keying).
1941 2,230,836 Hammond Electrical Musical Instrument (Original reverb patent).
1941 2,233,258 Hammond, Hanert Electrical Musical Instrument (Solovox keyboard).
1941 2,241,363 Hammond Electrical Musical Instrument (Auto pedal note).
1941 2,245,337 Hammond Electrical Musical Instrument (Tube top octave generator).
1941 2,245,338 Hammond Musical Instrument (The amazing Novachord!).
1941 2,251,051 Hammond Electrical Musical Instrument (Tone control).
1941 2,251,052 Hammond Electrical Musical Instrument (Vibrating reed vibrato).
1941 2,253,782 Hammond, Stephens Keyboard for Electrical Musical Instruments (Solovox).
1941 2,254,284 Hanert Electrical Musical Instrument (Single octave keyboard).
1941 2,254,366 Hammond Variable Impedance (Swell pedal system).
1941 2,260,412* Stephens Key Action for Musical Instruments (keycomb, etc.).
1941 2,262,179 Hammond Musical Instrument (Novachord case).
1941 2,262,494 Hammond Electrical Musical Instrument (Touch sensitive circuit).
1941 2,266,030 Hammond Electrical Musical Instrument (Envelope control).
1942 2,274,199 Hammond Electrical Musical Instrument (4-Channel organ system).
1942 2,276,389 Hammond Electrical Musical Instrument (Octave dividers).
1942 2,281,495 Hammond Frequency Generator (Electrostatic tone generation).
1942 2,301,869 Hammond Frequency Generating System (Tub oscillators).
1942 2,301,871 Hanert Electrical Musical Instrument (Double touch keyboard).
1943 2,310,429 Hanert Electrical Musical Instrument (Multichannel organ).
1943 2,314,496 Hammond Electrical Musical Instrument (Unusual tonewheel generator).
1943 2,323,392 Hammond, George Electrical Musical Instrument (Vibrato circuit).
1943 2,332,076 Hammond, Hanert Electrical musical instrument (Improved 4-channel organ).
1944 2,342,338 Hanert Electrical musical instrument (Percussion sound generator).
1944 2,357,191 Hanert Electrical Musical Instrument (Single octave pedal clavier).
1945 2,373,560 Hanert Sound Recording Method and Apparatus (Recording with vibrato).
1945 2,382,413* Hanert Electrical Musical Apparatus (Scanner vibrato).
1947 2,429,226 Hanert Electrical Musical Instrument (Keying system).
1947 2,432,151 Hammond Amplifying System (Amplifier with auto gain control).
1949 2,480,131 Hammond Electrical Musical Instrument (Coil-springs with pickups).
1949 2,480,132* Hammond, Hanert Electrical Musical Instrument (Single octave pedal clavier).
1950 2,498,367 Hammond, Hanert Electrical Musical Instrument (Chorus generator).
1950 2,499,244* Hammond, Stephens Pedal Clavier for Musical Instruments (spinet pedal clavier).
1950 2,500,820 Hanert Electrical Musical Instrument (Tube generators w/chorus effect).
1950 2,500,821 Hanert, Hammond Electrical Musical Instrument (Pedal generators w/slow decay).
1950 2,501,172 Hammond, Hanert Electrical Musical Instrument (Bass tone generator).
1950 2,506,451* Hammond Organ Console (M series spinet console design).
1950 2,508,514 Hanert, Hammond Electrical Musical Instrument (Complex first octave tonewheels).
1950 2,509,923* Hanert Electrical Musical Apparatus (Scanner vibrato improvements).
1951 2,560,568* Hammond, Hannert Vibrato Apparatus (Variable capacitor scanner).
1951 2,565,512* Meinema Tone Control Apparatus (Improved drawbars).
1951 2,577,752 Hanert Tone Quality Control Circuit for Electrical Musical Instruments.
1951 2,577,753* Hanert, Hammond E.M.I. with Tone Sustaining Means (M series pedal sustain).
1952 2,580,424 Hanert Vibrato Apparatus for Elec. Musical Inst. (Tube vibrato).
1952 2,583,566* Hanert Elec. Musical Inst. (Manual selective vibrato, 3 series).
1953 2,626,325** Hammond, Stephens Pedal clavier switch mechanism.
1953 2,645,968 Hanert Electrical Musical Instrument (Tube organ).
1953 2,646,468* Hanert Ear response compensated volume control apparatus.
1954 2,681,585 Hanert Elec. Musical Inst. Producing Chorus Effects (Tube chorus).
1957 2,790,906 Hammond Electronic oscillator (Adjacent notes share oscillator).
1958 2,828,659 Hanert Electrical musical instruments {Percussion circuit).
1958 2,835,876 Hammond Adjustable inductance (Adjustable inductors for tuning).
1958 2,845,831 Hammond Keyboard & Switching for E.M.I. (Chord organ buttons).
1958 2,846,913 Hammond Circular scale electrical musical instrument.
1959 2,878,708 Hanert Capacitive switching apparatus (Manual keying).
1960 2,905,040 Hanert Method and Apparatus for Producing Chorus Effects in Music.
1960 2,922,329 Hanert Elec. Musical Inst. with Multiple Utilization of Tone Sources.
1966 2,933,004 Wehrmann Combined Piano and Electrical Monophonic Instrument.
1960 2,942,070 Hammond, et. al. Means for Binaural Hearing (pseudo-stereo).
1960 2,943,527 Hanert Adjustable Tune Producing Instrumentality.
1960 2,949,805 Hammond Artificial Reverberation Control Apparatus.
1960 2,951,412** Hanert Electrical Musical Instrument with Percussion Apparatus.
1960 2,953,055** Hanert Percussion Tone Electrical Musical Instrument.
1960 2,953,056 Hanert Percussion Tone Electrical Musical Instrument.
1961 2,967,447** Hanert Apparatus for Translating Electrical Musical Tone Signals into Sound (Reverb).
1961 2,972,273 Hanert Polyphonic Percussion Control Apparatus.
1961 2,982,819** Meinema et. al. Artificial Reverberation Apparatus ("Necklace" Reverb).
1962 3,037,414** Meinema Artificial Revereration Control Apparatus.
1962 3,048,072 Hanert Apparatus for Producing Psuedo-Stereophonic Effects.
1962 3,051,032 Hanert Single Manual Double Countermelody Electrical Musical Instrument.
1962 3,070,659 Hanert Artificial Reverberation Control Apparatus.
1963 3,077,136 Hammond Capacity Tuned Oscillator
1962 3,109,878 Hanert Percussion Tone Monophonic Electrical Musical Instrument.
1966 3,260,784 Wehrmann Electronic Musical Instrument Having One or More Keyboards.
There are also a number of Design Patents:
1950 158,625 Stephens Electrical Musical Instrument (M series spinet, offset manuals, 1 octave pedals).
1961 190,140 Palma Electric Organ (A-122 Contemporary console design).
1962 192,450 Miller Electric Organ (A-102 French Provencial console design).
1962 192,882 Miller Electric Organ (A-101 Traditional console design).
* These patent numbers are found on the nameplate of M3 organs dating around 1953-1954.
** In addition to the patent numbers on the M3, these patent numbers are found on the nameplate of M100 organs.
*** In addition to 2,117,002, these patent numbers are found on Novachord nameplates
To retrieve these patents, copy the patent number and search the US Patent Office: 
http://patft.uspto.gov/netahtml/PTO/srchnum.htm
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In all, Laurens Hammond had 91 patents issued to him during his career. Many of the non-organ related patents were for electric clocks and aircraft controls.
See also DonLesliesPatents and CahillPatents
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