Patent ID: 8359823

Claim:
A steel cord comprises a core layer and an outer layer; said core layer comprising a first number of first steel filaments, said first number ranging from 3 to 8, said first steel filaments having a twist pitch greater than 310 mm; said outer layer comprising a second number of second steel filaments, said second number ranging from 3 to 10, at least one of said second steel filaments being polygonally preformed; said outer layer is helically twisted around the core layer with a core twist pitch, and the core twist pitch ranging from 15 R f to 150 R f when the average diameter of the second steel filaments is R f mm; characterized in that at least one of said first steel filaments is preformed into wavy form in one single plane, and the wave height ranges from 1.2 D f mm to 2.4 D f mm when the average diameter of the first steel filaments is D f mm, and the wave length ranges from 10 D f mm to 25 D f mm.