Sensing apparatus for inclinometers

Claim 1

Apparatus for sensing the direction and amplitude of tilt of an inclinometer for measuring the force velocity and direction of a current of a body of water movement comprising a cylindrical housing having end caps thereon, a spherical housing contained within said cylindrical housing, said spherical housing attached to an end cap a movable sphere within said spherical housing, a fluid contained within said spherical housing maintaining said sphere in spaced relation to said spherical housing, means for tethering said cylindrical housing in a body of water, a bar magnet mounted within said sphere below the center of gravity of said sphere, the center of gravity of the sphere and the center of gravity of the magnet defining a line which is perpendicular to the magnet for maintaining said sphere in a vertical position and oriented toward the magnetic north pole, the combination comprising a plurality of tuned circuits of different resonant frequencies mounted in great circles about said sphere and at substantially right angles to each other, each of said tuned circuits consisting of a plurality of coil windings connected in series with a capacitor, one of said tuned circuits lying in a common plane with said magnet, a drive coil mounted on said spherical housing at right angles to each of said tuned circuits and lying in a plane substantially parallel to that of said magnet when said cylindrical housing is positioned in an upright position, means for applying an impulse of electric current to said drive coil whereby a voltage impulse is induced in said tuned circuits causing said tuned circuits to oscillate inducing signals in said drive coil that indicate the amount of tilt of said cylindrical housing with relation to said sphere and further means for distinguishing the directions of tilt of said cylindrical housing.