For the creation and the repetition of a fabric sample, the functions of each single device contributing to the global functioning of the machine must be accurately controlled (for example: the position of the selection cams, of the raising and knock-over cams, the thread guide selection, the needle-bed racking, the variation of the carriage speed, etc.) The function control is carried out by means of systems which read the information for each specific manufacturing process.
According to the encoded language used, the information can be stored on different types of supports (cards, bars, magnetic tapes, flexible magnetic disks, CD-ROM, etc. to be prepared in advance) to control the positions of the elements affecting the shape, the structure and the design of the fabric.
The preparation of these elements that carry fundamental information is a crucial task for the knitting operator; the programming is fundamental for the machine and for the manufacturing of the desired fabric.
A) Octagonal card holder
Picture 42 - Program reading
On an automatic flat-bed machine, the program reading system (picture 42) includes several elements which read the programs stored on the punched cards: each hole corresponds to a specific function of the machine.
The cards are flexible and are wound on an octagonal prism.
During the rotation of the prism the points, carried by a carriage, are pushed by special cams and move leftwards touching the external side of the cards.
The holes on the cards provide to select the points which, through the rods, control the various functions.
The machine also includes a disk (picture 43) which controls and reduces the quantity of cards by positioning the command pegs according to the number of times the operator wants to reproduce the work cycle.
Picture 43 - Program reading system and disk
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