Yarn tension monitor has two monitor beams clamped at one end with the yarn passing partially round their free ends in opposite directions with sensors to register the beam bending to give signals to register the yarn tension

摘要

The mechanism to monitor yarn tension at a running yarn (5) has a monitor beam (1.1) which is clamped at one end and the yarn (5) path is deflected by the free end of the beam. A sensor (7) registers the beam (1.1) movement by the tension of the yarn (5) passing over the free end. A second monitor beam (1.2), clamped at one end and fitted with a movement sensor (11), is at a gap from the first beam (1.1) along the yarn (5) path, for the yarn (5) to be deflected round its free end in the opposite direction to the deflection at the first beam. The sensors (7,11) at both beams (1.1,1.2) are connected to an electrical circuit, where the sensor signals are converted into yarn tension values. The yarn (5) follows an S- or Z-path between and partially around the free ends of the two monitor beams (1.1,1.2). The monitor beams (1.1,1.2) are between an entry and exit yarn guide, with a symmetrical alignment to the yarn (5) path so that the forces are equal on their free ends through the effects of the yarn tension as they are deflected round them. Each monitor beam (1.1,1.2) is fitted with a further sensor (8,12), at a gap from their first sensors (7,11), along the longitudinal line of the beams. The paired sensors (7,8;11,12) are at a bending beam (3.1,3.2), and the yarn (5) is carried through a guide (2.1,2.2) bonded to it. The sensors (7,8,11,12) are each of paired stretch measurement strips, secured to opposite surfaces of the monitor beams. The strips are linked together by a Wheatstone bridge circuit. The monitor beams can each be of two bending beams, with a rigid lateral beam linking their free ends together so that a deflection loading on them is in opposite directions. Each bending beam is fitted with one or more sensors (7,8). An Independent claim is included for a system to measure the tension of a running yarn, where the yarn is deflected round the free ends of two beams and their movement is measured to determine the tension of the yarn. Preferred Features: The measured value of the yarn tension is formed by an addition of the measurement signals which correspond to the bending action on the beams at the free ends where the yarn passes partially round them.