The needles of a knitting machine are continuously monitored, during operation of the machine, by an optical head having a light source and an electro-optical receiver which receives the light beam from the light source after the beam has crossed the area of passage of the needles. The output signals...http://www.google.co.uk/patents/US5524460?utm_source=gb-gplus-sharePatent US5524460 - Device for continously monitoring the needles of a knitting machine during operation thereof
