Patent ID: 8720177

Claim:
A method of manufacturing a metal cord with three concentric layers (C 1 , C 2 , C 3 ) rubberized in situ, comprising a first, internal, layer or core (C 1 ) having M core wires, around which there are wound together in a helix, at a pitch p 2 , in a second, intermediate, layer (C 2 ), N wires of diameter d 2 , N varying from 3 to 12, around which second layer there are wound together as a helix at a pitch p 3 , in a third, outer, layer (C 3 ), P wires of diameter d 3 , P varying from 8 to 20, the method comprising: sheathing the core (C 1 ) with a rubber composition named a “filling rubber” in an uncrosslinked state; twisting, at an “assembling point” the N wires of the second layer (C 2 ) around the sheathed core (C 1 ) an intermediate cord named “core strand” of M+N construction; twisting the P wires of the third layer (C 3 ) around the core strand; and twist-balancing the metal cord to force the filling rubber in the uncrosslinked state toward the core to fill capillary gaps formed between the core (C 1 ) and the second layer (C 2 ), wherein a quantity of the filling rubber delivered during the sheathing is between 5 and 40 mg per gram of final cord.