Hammond and Leslie Patents

John Hanert and Don Leslie were separately the architects of the Hammond sound. Hanert worked for the Hammond company, which officially decreed that Leslie and all his works were anathema.

Here is a sampling of patents by Hanert, Leslie, Laurens Hammond, and several others from the Hammond Corporation. The links point to the Delphion patent server, which lets you do some simple searches on patents granted since 1971. Delphion also has links to many older patents which are referenced by the newer patents. So a search on "Hanert" finds a lot of patents by others which reference one of Hanert's patetnts.

Delphion lets you look at the first page of a patent for free, and has several options for ordering the full patent in a variety of formats.

Number Title overview detail page 1 granted to date granted date applied for
2,342,338 Electrical Musical Instruments overview page 1 J.M. Hanert February 22, 1944 June 20, 1942
2,429,226 Electrical Musical Instrument overview page 1 J.M. Hanert October 21, 1947 September 14, 1942
2,499,244 Pedal Clavier for Musical Instruments overview page 1 L. Hammond et al. February 28, 1950 February 27, 1948
2,509,923 Electrical Musical Apparatus overview page 1 J.M. Hanert May 30, 1950 March 8, 1946
2,577,753 Electrical Musical Instrument with Tone Sustaining Means overview page 1 J.M. Hanert December 11, 1951 August 22, 1949
2,580,424 Vibrato Apparatus for Electrical Musical Instruments overview page 1 J.M. Hanert January 1, 1952 August 22, 1949
2,622,692 Apparatus for Imposing Vibrato on Sound overview page 1 D.J. Leslie December 23, 1952 July 9, 1945
2,622,693 Apparatus for Imposing Vibrato on Sound overview page 1 D.J. Leslie December 23, 1952 July 9, 1945
2,626,325 Pedal Clavier Switch Mechanism overview page 1 L. Hammond et al. January 20, 1953 November 2, 1949
2,646,468 Ear Response Compensated Volume Control Apparatus overview page 1 J.M. Hanert July 21, 1953 February 1, 1950
2,687,665 Electrical Musical Instrument overview page 1 J.M. Hanert August 31, 1954 November 2, 1951
2,790,906 Electronic Oscillator overview page 1 L. Hammond April 30, 1957 May 28, 1949
2,828,659 Electrical Musical Instruments overview page 1 J.M. Hanert April 1, 1958 July 12, 1954
2,835,876 Adjustable Inductance overview page 1 J.M. Hanert May 20, 1958 August 18, 1950
2,846,913 Circular Scale Electrical Musical Instrument overview page 1 L. Hammond et al. January 20, 1953 November 2, 1949
2,878,708 Capacitive Switching Apparatus overview page 1 J.M. Hanert March 24, 1959 October 3, 1956
2,922,329 Electrical Musical Instrument with Multiple Utilization of Tone Signal Sources overview page 1 J.M. Hanert January 26, 1960 February 2, 1956
2,933,004 Combined Piano and Monophonic Instrument overview page 1 W.J. Wehrmann (Hammond?) July 12, 1966 November 5, 1964
2,943,527 Adjustable Tune Producing Instrumentality overview page 1 J.M. Hanert July 5, 1960 September 16, 1957
2,953,056 Percussion Tone Electrical Musical Instrument overview page 1 J.M. Hanert September 20, 1960 March 13, 1957
2,967,477 Apparatus for Translating Electrical Musical Tone Signals into Sound overview page 1 J.M. Hanert January 10, 1961 March 6, 1957
2,972,273 Polyphonic Percussion Control Apparatus overview page 1 J.M. Hanert February 21, 1961 March 12, 1958
3,048,072 Apparatus for Producing Psuedo-Stereophonic Effects overview page 1 J.M. Hanert August 7, 1962 April 27, 1960
3,051,032 Single Manual Double Countermelody Electrical Musical Instrument overview page 1 J.M. Hanert August 28, 1962 March 18, 1959
3,058,541 Rotary Electrostatic Speaker overview page 1 D.J. Leslie October 16, 1962 July 9, 1956
3,070,659 Artificial Reverberation Control Apparatus overview page 1 J.M. Hanert December 25, 1962 June 4, 1959
3,109,878 Percussion Tone Monophonic Electrical Musical Instrument overview page 1 J.M. Hanert December 25, 1962 June 4, 1959
3,260,784 Electronic Musical Instrument Having One or More Keyboards overview page 1 W.J. Wehrmann (Hammond?) July 12, 1966 November 5, 1964

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