Patents by Inventor Dexter Robert Plummer

Dexter Robert Plummer 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).

  • Mechanical gearing
    Patent number: 4059030
    Abstract: A mechanical gearing with a first rotatable member, three spherical balls in contact with and rotated by the first member, a second relatively flexible member in contact with the balls and a third rigid member fixed with respect to the second member and against which the second member is urged by the balls so that the second and third members rotate with respect to each other.
    Type: Grant
    Filed: November 25, 1975
    Date of Patent: November 22, 1977
    Assignee: Strathearn Audio Limited
    Inventors: Alexander Bennett Gosling, Dexter Robert Plummer, Colin Howard Stanwell-Smith
  • Method and apparatus for indicating angular displacement
    Patent number: 4032158
    Abstract: A tone arm for a record player having a mirror at one end is provided. Opposite the mirror are a light source and two detector elements. When the tone are pivots from a desired angle light from the source is reflected upon the element more than on the other. The mirror is convexly curved so that pivotal motions of the tone arm in one plane will not affect the amount of light reaching the detectors.
    Type: Grant
    Filed: September 3, 1975
    Date of Patent: June 28, 1977
    Assignee: Strathearn Audio Limited
    Inventors: Colin Howard Stanwell-Smith, Dexter Robert Plummer, Frederick James Easthope, Jonathan Humfrey Pope
  • Method and apparatus for use in cleaning a gramophone disc
    Patent number: 3992018
    Abstract: A combination of a turntable for playing phonograph records, a lid covering the turntable, tone arm for tracking record grooves, and a cleaning element mounted on the lid for movement into contact with a constant annular area on the top side of the record for cleaning. A counterbalance weight controls the pressure of the cleaning element upon the record.
    Type: Grant
    Filed: January 31, 1975
    Date of Patent: November 16, 1976
    Assignee: Strathearn Audio Limited
    Inventors: Dexter Robert Plummer, Gerald Avison, Colin Howard Stanwell-Smith, Keith Douglas Ridler