METAL CORD COMPRISING LAYERS HAVING HIGH PENETRABILITY
A metal cord has cylindrical layers formed of an internal layer, an intermediate layer, and an external layer. The in internal layer includes M threads. The intermediate layer includes N threads wound in a helix around the internal layer. The external layer includes P threads wound in a helix around the intermediate layer. An inter-thread distance, D 2 , between the threads of the intermediate layer is greater than or equal to 25 μm. An inter-thread distance, D 3 , between the threads of the external layer is greater than or equal to 25 μm.
1 - 20 . (canceled)
21 . A metal cord having cylindrical layers, the cord comprising:
an internal layer including M threads;
an intermediate layer including N threads wound in a helix around the internal layer;
an external layer including P threads wound in a helix around the intermediate layer,
wherein an inter-thread distance, D 2 , between the threads of the intermediate layer is greater than or equal to 25 μm, and
wherein an inter-thread distance, D 3 , between the threads of the external layer is greater than or equal to 25 μm.
22 . The cord according to claim 21 , wherein the inter-thread distance, D 2 , between the threads of the intermediate layer is greater than or equal to 30 μm.
23 . The cord according to claim 21 , wherein the inter-thread distance, D 2 , between the threads of the intermediate layer is greater than or equal to 40 μm.
24 . The cord according to claim 21 , wherein the inter-thread distance, D 2 , between the threads of the intermediate layer is greater than or equal to 50 μm.
25 . The cord according to claim 21 , wherein the inter-thread distance, D 3 , between the threads of the external layer is greater than or equal to 30 μm.
26 . The cord according to claim 21 , wherein the inter-thread distance, D 3 , between the threads of the external layer is greater than or equal to 40 μm.
27 . The cord according to claim 22 , wherein the inter-thread distance, D 3 , between the threads of the external layer is greater than or equal to 40 μm.
28 . The cord according to claim 21 , wherein the inter-thread distance, D 3 , between the threads of the external layer is greater than or equal to 50 μm.
29 . The cord according to claim 22 , wherein the inter-thread distance, D 3 , between the threads of the external layer is greater than or equal to 50 μm.
30 . The cord according to claim 21 , wherein a ratio of the inter-thread distances, D 2 /D 3 , between the threads of the intermediate layer and the threads of the external layer satisfies:
0.5≦ D 2/ D 3≦1.5.
31 . The cord according to claim 21 , wherein a ratio of the inter-thread distances, D 2 /D 3 , between the threads of the intermediate layer and the threads of the external layer satisfies:
0.7≦ D 2/ D 3≦1.3.
32 . The cord according to claim 21 , wherein a ratio of the inter-thread distances, D 2 /D 3 , between the threads of the intermediate layer and the threads of the external layer satisfies:
0.8≦ D 2/ D 3≦1.2.
33 . The cord according to claim 21 , wherein a ratio of the inter-thread distances, D 2 /D 3 , between the threads of the intermediate layer and the threads of the external layer satisfies:
0.9≦ D 2/ D 3≦1.1.
34 . The cord according to claim 21 , wherein
M=2, 3, or 4,
N=7, 8, 9, or 10, and
P=13, 14, 15, or 16.
35 . The cord according to claim 34 , wherein P=14 or 15.
36 . The cord according to claim 34 , wherein
M=2,
N=7, 8, or 9, and
P=14.
37 . The cord according to claim 34 , wherein
M=3,
N=8 or 9, and
P=14 or 15.
38 . The cord according to claim 34 , wherein
M=4,
N=7, 8, 9, or 10, and
P=14 or 15.
39 . The cord according claim 21 , wherein a diameter, d 1 , of each thread of the internal layer, a diameter, d 2 , of each thread of the intermediate layer, and a diameter, d 3 , of each thread of the external layer satisfies:
0.15≦d1,d2, d3≦0.5 mm.
40 . The cord according to claim 21 , wherein a diameter, d 1 , of each thread of the internal layer, and a diameter, d 2 , of each thread of the intermediate layer satisfies:
d 1/ d 2>1.
41 . The cord according to claim 21 , wherein a diameter, d 1 , of each thread of the internal layer, and a diameter, d 2 , of each thread of the intermediate layer satisfies:
1.05≦ d 1/ d 2≦1.3.
42 . The cord according to claim 21 , wherein a diameter, d 1 , of each thread of the internal layer, a diameter, d 2 , of each thread of the intermediate layer, and a diameter, d 3 , of each thread of the external layer satisfies one or both of:
d1>d2, and
d1>d3.
43 . The cord according to claim 21 , wherein a direction of winding of the threads of the external layer is different from a direction of winding of the threads of the intermediate layer.
44 . The cord according to claim 21 , wherein the threads of the internal layer are not pre-formed.
45 . The cord according to claim 21 , wherein the cord is a metal cord and is incorporated as an elementary strand of a multi-strand rope-cord.
46 . The cord according to claim 21 , wherein the cord is a metal cord and is incorporated in a tyre.
47 . The cord according to claim 21 , wherein the cord is a metal cord and is incorporated in a caterpillar track.