Patent ID: 7509821

Claim:
A yarn measuring device for a flat bed knitting machine which has a chassis, a needle bed located horizontally on the chassis, a track located above the needle bed and in parallel therewith, and a carriage straddled the track and movable horizontally thereon and having two ends each fastened respectively to a cam controller and a mask plate located at one end thereof, the yarn measuring device comprising: a counter which is located on the chassis close to a distal end of the track and has an axial grating wheel which has a plurality of apertures formed in a circular array and equally spaced manner and a primary wheel and an U-shaped sensor, the grating wheel being extended between two ends of the sensor; a detection unit which is located on the chassis in parallel with the needle bed and opposing the mask plate and has a first sensor and a second sensor spaced from each other at a selected distance in an U shape; and a programmable logic circuit controller which is located at one side of the chassis and has a processor, a display and a programmable control interface that are electrically interconnected, the programmable logic circuit controller, the counter, the detection unit, the carriage and the cam controller being electrically interconnected.