Weft storage device with an apparatus for measuring weft storage quantity for loom

Abstract

A weft storage device comprises a stationary cylinder (12) supporting a plurality of yarn loops (RT) wound helically along its outer surface. A finger (28) with a magnet (38) incorporated therein is mounted in an elastically yielding way along the outer surface of the cylinder under the pressure of the yarn wound on the cylinder, to be biased from a first position projecting outside the outer surface, to a second inner position, and vice versa. A sensor (40) is supported in front of the magnet (38) in a stationary position relative to the cylinder to generate an output signal (U) proportionalto the distance between the magnet and the sensor.

Description

technical field [0001] The invention relates to a weft feeder for a loom, especially a fluid jet loom, with a device for measuring the weft reserve on the loom. Background technique [0002] A typical weft feeder for a loom consists of a fixed cylinder on which a motorized swivel arm winds a number of turns of weft yarn to form a weft yarn reserve. Once requested by the loom, the weft yarn is unwound from the cylinder and delivered to the loom. [0003] The above-mentioned weft feeder is generally provided with a weft yarn pre-measurement device, which has the function of stopping the unwinding of the weft yarn when each weft is inserted and the required number of weft yarn turns has been introduced. This device usually includes a motorized needle that operates on the basis of a signal generated by a turn count sensor on the unwinding coils to lock / unlock the unwinding coils. [0004] A second sensor is provided for counting the coils wound on the drum so that the reserve ...

AI Technical Summary

Problems solved by technology

[0005] But in the event of a fault in the weft insertion, such as when the weft yarn is entangled in the gauge yarn or the weft feed nozzle is not adjusted accurately in a fluid jet loom, the loop-counting sensor may not be able to detect a few unwound yarn loops, thereby disabling the reserve measurement system and causing a corresponding uncontrolled reduction in the weft reserve

[0006] The above situation affects the correct operation of the weaving equipment because the loop unwinding resistance is higher when the reserve is reduced

This can cause a "short" weft thread introduction, i.e. a late introduction, or it can also cause an excessive rise in air pressure

[0007] However, restoring the correct working condition requires stopping the machine and manual intervention by the operator, which is obviously inconvenient

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