Yarn Supervisor by Drop and Tearing for Textile Machinery

Some yarn faults announce themselves as a break; others arrive quietly as a slack, ballooning or run-out end that is still physically present but no longer feeding. A combined yarn supervisor — by drop and tearing — exists for that awkward middle ground. It carries both sensing principles in one head on the yarn path of a circular or flat knitting machine: a drop element that falls when the yarn supporting it disappears, and a tearing response that reacts when a held end pulls away under tension. Either fault trips the same stop motion, so the machine halts for the full family of yarn failures rather than only the clean breaks a single-principle device is best at.

Two Sensing Principles in One Stop Motion

The drop side of the unit works by gravity and presence. The yarn, on its way to the feeder, supports or deflects a light drop element; while yarn is there, the element stays up and the circuit stays closed. Lose the yarn — break, run-out package, end slipped off its path — and the element drops, tripping the stop. The tearing side works by tension and absence: the yarn is held through the sensing point, and a break that whips the end away registers even in cases where a slack remnant might fool a pure drop device into thinking yarn is still present. Together they cover the two ways an end can fail — gone slack, or gone altogether — which is precisely why mills fit combined units on machines running varied yarns, fancy effects or multiple feeders where fault behaviour is hard to predict.

Combined heads ask a little more of the setter than single-principle units. Both responses must be proved at fitting — a deliberate break and a deliberate run-out should each stop the machine — and the yarn path through the head must be threaded exactly as the maker intends, because a mis-threaded combined unit can quietly become a single-principle one, watching for one fault while the other walks past it.

When to Choose Combined Supervision — and How It Wears

Choose the combined unit where the cost of a missed fault is high and the fault mix is mixed: striped and jacquard work with many ends, machines that change yarn types often, and any knitting where a slack end can wrap, tangle neighbouring feeders or feed double before anyone notices. On simple, stable single-yarn work a single-principle supervisor is cheaper and easier to keep honest; the combined head earns its place by catching the faults the simple head argues about. Its wear map is the union of both parents: drop pivots and wires that bend, groove or stiffen, tearing guides and springs that fatigue, and a doubled need for cleaning, since fly can jam either mechanism independently.

RMB Massardi of Italy, listed below, lists yarn supervisors by tearing and drop in its knitting machine parts range, alongside the separate by-drop and by-tearing units, yarn sensors, retainers and slide electronic yarn control devices — so a mill can standardise on one maker's family across machines with different supervision needs. Specify machine make and model, feeder position, yarn count range and the stop-circuit contact arrangement when ordering, and test both trips after every head change. Keep a complete spare combined head per machine type: with two mechanisms inside, field repair is a bench job, while swapping the head is a minute's work.

Companies Supplying Yarn Supervisor by Drop and Tearing