Patent ID: 7299762
Filing Date: 2007-11-27
Classification: B63B,B64F

Abstract:
1. A system for maintaining a surface in a desired orientation, comprising: at least two columns that are rotatably coupled along engaging surfaces that are oriented at an angle with respect to a perpendicular cross section of the columns, said at least two columns including a first column that is rotatably coupled to the surface and a second column rotatably coupled to a supporting surface; a linkage that joins the surface to be maintained in a desired orientation and the supporting surface and allows the surface to move with respect to the supporting surface but not to rotate with respect to the supporting surface: means for rotating the first column with respect to the second column and means for rotating the second column with respect to the supporting surface; one or more frictionless bearings for rotatably coupling the columns; a sensor for producing an orientation signal; and a computer for selectively driving the means for rotating the first and/or second column to maintain the surface in the desired orientation.