Patents by Inventor Jonathan P. Freeman

Jonathan P. Freeman 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: 5543968
    Abstract: A helmet mounted display system comprising: a transparent visor; and an optical system which directs rays of light from a display produced by a display source onto a spherical region of the visor to provide by reflection at the visor, at a helmet wearer's eye position, a collimated virtual image of the display on a line of sight of a wearer of the helmet through the visor; the region of the visor being of a shape which is rotationally symmetric about a first axis and the optical system being mounted for rotation about the first axis, thereby to allow rotation of the eye position about the axis.
    Type: Grant
    Filed: March 24, 1995
    Date of Patent: August 6, 1996
    Assignee: GEC-Marconi Limited
    Inventors: Jonathan P. Freeman, Martyn Ingleton, Christopher B. Staveley
  • Patent number: 4437957
    Abstract: To protect a structure immersed in an electrolyte, at least two protection units are located adjacent to different regions of the protected structure. In a preferred embodiment, each of these protection units includes a circuit for applying rectified alternating current voltage between the structure and electrodes immersed in the electrolyte adjacent to the different regions of the structure. Also, each of the protection units includes reference cells to produce direct current voltage between the reference cells and the structure, a measuring circuit coupled to the reference cells for measuring the potential between the reference cells and the structure, and a control circuit for controlling the level of the rectified alternating current voltage at the different regions of the structure in accordance with the measured potential levels.
    Type: Grant
    Filed: May 3, 1982
    Date of Patent: March 20, 1984
    Assignee: Freeman Industries, Inc.
    Inventor: Jonathan P. Freeman
  • Patent number: 4255242
    Abstract: In making measurements of the potential of a structure immersed in an electrolyte, which structure is being protected from corrosion by a cathodic or anodic protection system, serious errors are often introduced by the IR drop component induced by current flowing between the cathode and anode of the protection system on a reference cell which is used for measurement. To overcome this, a system is provided of the type including means for applying a rectified alternating current voltage between the structure and an electrode which is immersed in the electrolyte and spaced apart from the structure. A direct current reference source is coupled to the structure. A reference cell is located in the electrolyte and spaced apart from the structure.
    Type: Grant
    Filed: August 9, 1979
    Date of Patent: March 10, 1981
    Assignee: Freeman Industries, Inc.
    Inventor: Jonathan P. Freeman