Patent ID: 7504617

Claim:
Device for detecting a thread during the detection of thread ends in a suction pipe through which air flows, with a sensor mechanism comprising a transmitter and a receiver, wherein a measuring field is formed between the transmitter and receiver and the suction pipe has a curvature in the region of the measuring field, characterized in that the suction pipe ( 17 ) has an elongate recess ( 27 ) on the smaller radius of curvature, which recess is oriented in the running direction of the suction pipe ( 17 ), in that the recess ( 27 ) is outwardly curved in the wall of the suction pipe ( 17 ) and is channel-shaped, in that the transmitter and the receiver are each arranged at opposing side walls of the recess ( 27 ), in that at least the beginning of the recess ( 27 ) is located in the region of the curvature of the suction pipe ( 17 ), in that the wall of the suction pipe ( 17 ) forms the guide of the detected thread at the beginning and end of the recess ( 27 ) and the thread course of the detected thread oriented by the guide is always located inside the suction pipe ( 17 ), in that the thread is tensed inside the recess ( 27 ) and the thread course inside the recess ( 27 ) crosses the measuring field ( 26 ) and is at least partly spaced apart from the bottom ( 30 ) of the recess ( 27 ).