Method and device for automatically measuring the yarn length fed to a rectilinear machine
AssigneeBtsr International S.P.A.
InventorTiziano Barea
Life of this patent
Estimating the term…
Abstract
A method and device for automatically measuring the yarn length absorbed by a rectilinear machine adapted to produce an article and including a carriage movable to-and-fro over a needle bed between two ends of a working path, needles moving towards the carriage to cooperate with the yarn (F) and form an article, the yarn unwinding from a feeder with elements for measuring the yarn quantity fed at constant tension towards the needle bed. The feeder measures and constantly monitors the yarn feed velocity, this monitoring enables the fed and knitted yarn quantity to be obtained in real time and each measurement to be associated with the respective carriage travel stroke, this information enabling precise regulation of the knitting cams.
Claims12
A method for automatically evaluating the yarn length absorbed by a rectilinear machine to produce an article, the machine comprising a needle bed and a carriage;
- comprising the steps of:
- moving, above the needle bed, said carriage carrying at least one thread guide, said carriage moving between two ends of a working path in accordance with a first and a second operative phase which take place along opposing movement directions,
- during this movement said carriage selectively raising and lowering, from and into said bed, needles arranged to cooperate with said yarn to form the article,
- unwinding said yarn from a feeder, this feeder comprising means for measuring the yarn quantity fed towards said needle bed, yarn feed taking place at constant tension,
- the feeder measuring the yarn feed velocity during each operative phase, and if this feed velocity is greater than a threshold value the yarn quantity fed in the respective operative phase is measured until said feed velocity attains a value less than the threshold value,
- the values of these quantities measured during each operative phase being algebraically added to a value relative to the yarn quantity fed to the carriage during each phase to enable the carriage to pass from one end to the other of the working path and vice versa,
- from this algebraic sum there being determined the yarn quantity effectively fed to the needles for article production during each operative phase.
A device for automatically evaluating the yarn length absorbed by a rectilinear machine to produce an article, the machine comprising
- a needle bed and a carriage, wherein above the needle bed the carriage is moveable carrying at least one thread guide, said carriage moveable between two ends of a working path in accordance with a first and a second operative phase which take place along opposing movement directions, during this movement said carriage selectively raising and lowering, from and into said bed, needles arranged to cooperate with said yarn to form the article,
- a feeder for unwinding said yarn from the feeder, this feeder comprising means for measuring the yarn quantity fed towards said needle bed, yarn feed taking place at constant tension,
- means for measuring the velocity of yarn feed by the feeder during each operative phase,
- means for measuring the fed yarn quantity arranged to operate while the measured velocity exceeds a threshold value,
- means for controlling and evaluating the yarn quantity fed during each operative phase and arranged to calculate an algebraic sum by algebraically adding the data of these measured quantities to a value relative to the yarn quantity fed to the carriage during each phase to enable said carriage to pass from one end to the other of the working path and vice versa, from this algebraic sum said controlling and evaluating means determining the yarn quantity effectively fed to the needles for article production during each operative phase, and if necessary intervening to maintain the yarn tension at a constant value during each operative phase.
Dependencies are inferred from the claim text.