Rollermills

In a rollermill comprising a pair of rotatable grinding rolls, means mounting one of said rolls for displacement relative to the other and comprising a movable actuating member for determining said displacement, resilient means providing a roll separation resisting force acting directly on said member for urging said one roll toward the other roll for normally maintaining the surfaces of said rolls in grinding engagement while permitting separation of said surfaces in the event an obstacle passes between them during grinding, and means including shear pin means effective after a predetermined separation of said surfaces permitted by said resilient means for substantially solidly resisting further movement of said member and thereby resisting further relative separation of said surfaces, said shear pin means being constructed and arranged to fail upon said predetermined separation of said roll surfaces when the roll separation force acting on said member exceeds the combined resisting forces of said resilient means and said shear pin means to permit increased separation of said surfaces to non-grinding position while the full force of the resilient means alone remains acting on said member, whereby in the event of failure of said shear pin means and subsequent passage of the condition causing said increased separation of the roll surfaces said resilient means will continue with full force to urge said surfaces toward normal grinding relation.