Device for monitoring yarn motion on a textile machine

A sensing device responsive to ballooning motion of a yarn travelling on a textile machine, comprising first and second plate-shape elements interconnected by third plate-shaped insulating means in sandwich configuration, said first and second plate-shaped elements alternately confining a substantially circular yarn channel in the peripheral direction thereof, and structured to define regions of alternating sensitivity in the circumferential direction of the circular yarn channel for detection of the ballooning motion of the yarn, and a plate-shaped piezoelectrical transducer element attached to one of said first and second plate-shaped elements, for generating an electrical sensing signal when said one plate-shaped element is contacted by the travelling yarn.

A sensing device responsive to ballooning motion of a yarn travelling on a textile machine, comprising a yarn guide structure forming a yarn channel surrounding the travelling yarn, yarn motion responsive electrode means and means non-responsive to yarn motion arranged in alternate sequence at said yarn quide structure in circumferential direction of the yarn channel at surface of said yarn channel, and said yarn motion responsive electrode means generating an electrical signal when acted upon by the travelling yarn.