Device for verifying the correct employment of the yarns used in a textile machine, in particular a knitting or hosiery machine

A device for verifying the correct employment of yarns used by textile machines, comprising:

• means for memorizing information regarding yarns movements obtained during the production of a master fabric, the production of said master fabric comprising a self-learning phase of the features of a production cycle of the master fabric,
• a number of sensor means equal to the number of yarns used by the machine during production, each of said sensor means sensing the movement or stoppage of the corresponding yarn, the velocity of travel of the corresponding yarn towards the machine and the breakage of yarn, said sensor means generating an electrical signal proportional to the state of the yarn whether in movement or stopped,
• first comparison means for comparing each signal generated by said sensor means during production in subsequent cycles with the information memorized during the production of the master fabric, said first comparison means emitting a signal indicative of an error between said signals generated by said sensor means and the information memorized during the production of the master fabric, the error being indicative of an error in the movement of the corresponding yarn of said sensor means corresponding to a breakage or unscheduled stoppage of the yarn, said first comparison means comprising means for detecting consecutive errors at each one of said sensor means, means for determining whether the consecutive errors are of the same type, and indicator means for indicating a general error, a general error being indicated only if an error indication is provided by both said means for detecting consecutive errors at a same one of said sensor means and said means for determining whether the consecutive errors are of the same type;
• means for halting the machine,
• means for comparing the velocity of travel of each yarn measured by said corresponding sensor means with a corresponding velocity memorized during the production of the master cycle and for detecting a difference between said velocities,
• means for detecting the commencement and termination of the machine cycles,
• means for generating a timing signal based on the rotational speed of a drive shaft of the machine,
• memory means for memorizing signals generated by said timing means, and
• second comparison means for comparing data memorized by the memory means with the data memorized during the production of the master fabric and determining the difference between the data memorized by the memory means and the data memorized during the production of the master fabric, said difference being compared with an acceptability value, said data being compared at the end of the production cycle.