Patent ID: 7579564
Filing Date: 2009-08-25
Classification: G01L

Abstract:
1. A level indicating apparatus adapted to sense a level of a bulk material contained in a structure comprising: (a) a housing adapted to be mounted to the structure; (b) a paddle shaft supported by bearings in the housing and extending into the structure, the shaft rotating about an axis in an oscillating motion; (c) a paddle over-travel mechanism attached to an end of the paddle shaft that is located outside of the housing, the over-travel mechanism providing an over-travel movement that is induced by a movement of the bulk material contained within the structure; (d) a paddle connected to the over-travel mechanism, the paddle being oriented along its length at a downward angle from the shaft, the paddle moving in a swinging motion due to the motion of the shaft, the paddle extending into the structure; (e) a rotary drive motor mounted within the housing, the motor being operatively coupled to the paddle shaft; (f) a switch that changes state when a predetermined value of counter-torque on the shaft is detected, thereby indicating that the bulk material is present at the paddle; whereby the paddle is capable of engaging the bulk material and may also move to a substantially vertical downward position by an urging of the bulk material so as to avoid damage to the paddle, over-travel mechanism, and paddle shaft.