Level gauge that measures inclination angle having a rolling member that verifies levelness

A level gauge comprising:

• a housing comprising a bottom wall and a side wall, a surface of the side wall comprising a first scale, and the bottom wall and the side wall enclosing a receiving cavity;
• a vertical member in the receiving cavity and comprising an axis maintained in a vertical orientation in a natural state;
• a perpendicular member, a center of gravity of the perpendicular member being arranged on top of the vertical member, and a plane of the perpendicular member being maintained perpendicular to the axis of the vertical member;
• a rolling member rotationally arranged on a top surface of the perpendicular member;
• and
• an attracting device configured for attracting the rolling member to the center of gravity of the perpendicular member when the attracting device being turned on;
• wherein:
• when the bottom wall is placed on a gauging surface, the axis of the vertical member is maintained in the vertical orientation to drive the plane of the perpendicular member to be in a horizontal orientation, a maximum value of a value of the first scale corresponding to a highest portion of the perpendicular member in the vertical orientation and a value of the first scale corresponding to a lowest portion of the perpendicular member in the vertical orientation is an inclination angle of the gauging surface, and a straight line between the center of gravity of the perpendicular member and the maximum value is an inclination direction of the gauging surface;
• when the bottom wall is placed on the gauging surface and the maximum value is zero, the vertical member is held perpendicular to the bottom wall to hold the perpendicular member parallel to the bottom wall, and the attracting device is turned off to release the rolling member, the rolling member remains at the center of gravity of the perpendicular member if the gauging surface is level, and the rolling member rolls if the gauging surface is inclined.