Method of coating metal filament with rubber, method of producing cord, cord, rubber coating apparatus and cord producing apparatus

A method of coating a plurality of metal filaments with rubber for manufacturing a reinforcing cord, comprising:

• guiding the plurality of metal filaments together in a juxtaposed, untwisted and untwined state to a single opening of a mouthpiece of an extruder;
• and
• extruding the plurality of metal filaments in the juxtaposed, untwisted and untwined state, together with rubber, from the single opening of the mouthpiece so that the plurality of metal filaments in an untwisted and untwined state are coated with the rubber,
• wherein the mouthpiece has a width which allows the plurality of metal filaments to be disposed in a linearly juxtaposed manner therein, and
• the plurality of metal filaments are maintained in the juxtaposed and untwisted state in the mouthpiece so that the plurality of metal filaments are linearly supplied along a pass line linking the rubber coating apparatus and a filament twisting machine,
• wherein the mouthpiece has a width W calculated by Formula (1) and Formula (2), provided that B represents a clearance in the filament-juxtaposed direction between an outer peripheral edge of the mouthpiece and the corresponding outermost metal filament, and
• wherein:
• width(mm)=diameter t(mm) of metal filament×(number of metal filaments to be coated with rubber−1)+t×A Formula (1)
• A=(clearance B×2+diameter t of metal filament)/diameter t of metal filament Formula (2).