Method of detecting state of cutting rubber sheet having parallel cords embedded therein

A method of detecting a state of an operation of cutting a rubber sheet having a number of cords embedded therein in parallel with each other by moving a cutter in a cutting direction which is parallel to a direction in which the cords extend, comprising the steps of:

• detecting a displacement of said cutter in a direction of the thickness of the rubber sheet to generate a first displacement signal;
• detecting a displacement of the cutter in a direction perpendicular to the cutting direction to generate a second displacement signal;
• comparing said first displacement signal with a first criterion which is predetermined in relation to a diameter of the cord;
• generating a comparison signal for a predetermined time period when said first displacement signal exceeds the first criterion;
• comparing said second displacement signal with a predetermined second threshold value within the predetermined time period of said comparison signal;
• and
• generating an abnormal signal when the second displacement signal exceeds said second criterion.