Method and apparatus for measuring the expansion of a mat of fibrous material

摘要

A method and apparatus for measuring the expansion of a mat of fibrous material in which a contact plate is periodically moved vertically into and out of contact with the surface of a mat of fibrous material, contact between the contact plate and the surface of the mat is sensed, and the position of the contact plate is recorded responsive to the occurrence of contact between the contact plate and the surface of the mat.