Patent ID: 6217756
Filing Date: 2001-04-17
Classification: E03F

Abstract:
A grate system which closes to exclude trash and debris from passing through an opening when accompanied by water at an acceptably slow or slower rate of flow, and which opens to permit passage of such material and water when the flow rate of the water is at a faster rate which equals or exceeds said acceptable rate, said opening being formed in rigid structure where it will receive said water, said grate system comprising;a grate hingedly mounted to said structure having a closed position across said opening, and a raised position out of said opening, said grate forming gaps permitting flow of water past it, but said gaps being so proportioned and arranged that the grate can retain objects of an objectionable size when closed;an actuator so disposed and arranged as to receive water passed through said opening at said higher rate of flow, said actuator comprising a container having a drain opening to drain water from said actuator at a predetermined rate;linkage mounting said actuator for upward and downward movement, so disposed and arranged as to place the actuator where it will receive water which passes through the opening at or above said higher rate of flow, and connected to said grate so as to enable the grate to extend across the opening at said slow or no rates of flow, and to move away from it at said higher rates of flow when the rate of flow into the actuator sufficiently exceeds the rate of drainage through said drain port.