Patents by Inventor John D. Hamtil

John D. Hamtil has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5483748
    Abstract: A sound indicative leveling apparatus comprising an arcuate leveling tube having free and sealed ends extended upwards; a coupling mechanism for securing an external object to be leveled above or below the leveling tube; leveling circuitry further comprising a power source for supplying electrical energy; oscillation circuitry coupled to the power source and adapted to be keyed by an oscillation activation signal for generating speaker activation signals at given frequencies; a speaker coupled to the oscillation circuitry for generating audible tones upon receipt of the speaker activation signals; a switch mechanism disposed along the leveling tube and extended therein and coupled between the oscillator circuitry and the power source; and liquid conductive material disposed within the leveling tube of an amount to electrically engage the switch mechanism based upon leveling tube orientation and thereby generate an oscillator activation signal.
    Type: Grant
    Filed: August 3, 1994
    Date of Patent: January 16, 1996
    Inventors: Lyle W. Groves, Martha R. Groves, John D. Hamtil