| 摘要 |
PCT No. PCT/EP96/05175 Sec. 371 Date Sep. 12, 1997 Sec. 102(e) Date Sep. 12, 1997 PCT Filed Nov. 22, 1996 PCT Pub. No. WO97/19425 PCT Pub. Date May 29, 1995The apparatus for determining the stiffness of sheet material is provided with mechanical means which periodically touch the sheet material, causing it to vibrate. The sounds produced by the vibration are detected by a detector. From the detected sounds an evaluating device determines the stiffness of the sheet material. The sheet material is held or guided in a transport device such that it can yield to the mechanical action within certain limits in the area of contact without being irreversibly deformed. |
