Patent ID: 6044871
Filing Date: 2000-04-04
Classification: D03D

Abstract:
An improved optical feeler for monitoring a thread reserve in weft feeders, comprising a light-emitting device constituted by a light source directing light rays onto a thread wound in spaced turns on a drum of the feeder, and a receiver means, which collects the light rays and converts them into electrical signals which indicate presence or absence of turns of thread, the optical feeler further comprising a first focused optical transmission system, which forms a first pointlike luminous image of the light source on the turn being monitored and, in the absence of the turn, a second pointlike luminous image of the light source located on a screen surface which is arranged below the turns, and a second focused optical projection system which selectively projects the first or second luminous image, along respective differentiated optical paths, which have a different length, onto at least one optical sensor capable of emitting discriminated signals which correspond to a discriminated length of the corresponding optical paths that separate the first and second pointlike images from the optical sensor.