Patents by Inventor Bruce G. Key

Bruce G. Key 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).

  • Device for defining a horizontal plane
    Patent number: 5272814
    Abstract: A device for defining a plane to determine relative elevations comprising in combination a stationary housing (7) having an aperture (8) and locating a pair of vertical reflecting surfaces (6) at right angles to each other which may be a pair of mirrors (5) or a right angle prism (32) and a levelling rod or staff (14) adapted to be positioned at a vewing distance from the housing (7) and incorporating a light source (12) and an eyepiece (15) whereby an observer at the location of the levelling rod (14) can move the light source (12) up and down the levelling rod (14) until a reflection of the light from the light source (12) is seen in the pair of reflecting sufaces (6). A reading can then be taken on the levelling rod (14) at a point midway between the eyepiece (15) and the light source (12) which defines a horizontal line from the reflecting surfaces (6).
    Type: Grant
    Filed: October 8, 1991
    Date of Patent: December 28, 1993
    Inventor: Bruce G. Key