Device for detecting the presence of yarn fed to needles on knitting and hosiery machines

Abstract

The invention concerns knitting and hosiery machines and in particular a system for detecting the presence of yarn being fed to the needles on the cylinder of such machines. Each yarn is fed to the needles through a yarn guide moving between an out of work to a work position and is associated with a sensor capable of detecting movement/presence of the yarn and to stop the machine when the yarn guide moves from the out of work to the work position and there is no movement/presence of the yarn.

1 . A system for controlling the presence of the yarns being fed to the needles on the cylinder of circular knitting and hosiery machines with the object of stopping the machine when a lack of yarn occurs, and where each yarn being supplied through a yarn guide moving from an out of work, idle position to a work position, characterised by the feature of associating each yarn feeding the needles through a related yarn guide, with a sensor capable of detecting the flow/presence of the yarn itself, and to cause the stop of the machine when the yarn guide is moved from the out of work position to the work position and said sensor releases a signal which is indicative of absence of flow of the related yarn to said yarn guide.  
     
     
         2 . The system according to  claim 1 , wherein the sensor associated with each yarn is placed in connection with the electric circuit of a motor which drives and controls the rotation of the cylinder with needles of the machine and with means controlling the in and out of work movements of the yarn guide corresponding to said yarn, so that the movement of the yarn guide to the work position concurrent with a failure to detect movement of the yarn on the part of said sensor causes the electric circuit to open, stopping the machine.