Pressure relief door with counterweight mechanism

摘要

A counterweight mechanism that includes a radial arm with a weight and a series of elements interconnected between the door and the arm. The weight provides a closing force when in a first position and provides an opening force when in another position. The weight may be an over center weight and the closing force reduces when the weight moves toward an over center position. The counterweight mechanism may require manual resetting after the weight is in the second position. Door movement may be though an angle that is less than an angle of movement of the radial arm.