System for detecting the presence of a yarn on a continuous spinning frame

摘要

The system according to the invention comprises a sensor composed of a movable unit formed by an electrical circuit in which are placed two supple blade switches closed by a rocking member in response to the presence of a yarn. Said circuit comprises a conductor wound on a magnetic core. The data transmitting device comprises a fixed looped conductor of which one part is parallel to the path followed by the sensor and traverses the core. Means are provided for generating oscillations in the looped conductor, as well as means for detecting a variation in the oscillating conditions induced by a change of state of the electrical circuit due to the closure of one switch and indicating that the sensor has met up with a yarn. Due to the detection of the variations in the oscillating conditions, it is possible to find out the number of breakages occurring in the textile machine.