Method and device for recognition of a tear-off strip on a material web
AssigneeFocke & Co. (GmbH & Co.)
InventorsHeinz Focke, Doris Focke, Michael Czarnotta
Life of this patent
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Abstract
In order to check a material web (12), in particular a film web, with regard to the correct arrangement of a tear-off strip (11) extending in the longitudinal direction of the material web (12), ultrasonic transmitters are used, specifically an ultrasonic transmitter (11) on the one hand and an ultrasonic receiver (19) on the other hand. The sensors are arranged on opposite sides of the material web (12) in such a way that, if appropriate, focused ultrasonic waves are aimed specifically at the region of the tear-off strip (11). If a tear-off strip (11) is missing, an appropriate signal is generated by the ultrasonic receiver (19).
Claims7
A method for detecting a tear-off strip (11) or a tear-off thread on a material web (12) or film web with the aid of sensors, characterized by the following features:
- a) the sensors are ultrasonic transmitters (18), on the one hand, and ultrasonic receivers (19), on the other hand, which are positioned on different sides of the material web (12),
- b) ultrasonic transmitter (18) and ultrasonic receiver (19) are positioned such that the material web (12) conveyed between ultrasonic transmitter (18) and ultrasonic receiver (19) is registered by ultrasonic waves substantially exclusively in the region of the tear-off strip (11) or tear-off thread,
- c) the ultrasonic transmitter (18) is constructed in such a way that a lobe or response curve generated by the latter corresponds approximately to the width of the tear-off strip (11),
- d) the ultrasonic receiver (19) is connected to an evaluation unit which reacts to changes in the intensity of the waves picked up.
Dependencies are inferred from the claim text.