Patent ID: 9738484
Date: 2017-08-22
CPC Classifications: B65H,D03D,D04B,G01D

Claim:
1. A storage yarn feeder, comprising: a motorized rotary drum supported on a motor housing and adapted to bear a plurality of yarn loops wound thereon, such loops being adapted to be unwound upon request from a downstream machine, and a yarn-unwinding sensor which is adapted to count the yarn loops unwinding from the motorized rotary drum, wherein said yarn-unwinding sensor comprises: light-emitting means which are integral with the motor housing, light-receiving means which are integral with the motor housing, light-guiding means which are integral with the drum, and are arranged to guide the light from said light-emitting means to a window which is defined on the rotary drum in a position such that it is repeatedly engaged by the yarn during its rotary unwinding motion, and vice versa, a reflecting surface which is adapted to reflect the light coming out of said window back towards said window, and light-deviating means which are integral with the motor housing and arranged to deviate the light coming back from said window towards said light-receiving means, whereby the unwinding of a yarn loop from the drum is determined on the basis of the variation of light resulting from the yarn transiting on said window.