Appeal 2007-1902
Application 09/398,006
same relative to the equatorial plane as the direction of the cords of
outermost cord layer H.
We find Gaudin would have acknowledged with respect to heavy duty
pneumatic radial tires with at least three cord layers of rubber coated
metallic cords having different inclination angles to the equatorial plane, that
[i]n a conventional arrangement the cords of the radially
innermost first [cord layer] are inclined at a relatively large
angle with respect to the equatorial plane . . . while the cords of
the adjacent second and third [cord layers] are inclined at
relatively small angles with respect to the tire equatorial plane
and in opposite directions to each other. Accordingly crossing
angles of the cords of the radially innermost three [cord layers]
form a triangulated structure which, together with the stiffness
of the cords themselves, provides an effective . . . belt of high
rigidity in the longitudinal and axial directions of the belt, thus
keeping the tire tread flat on the road surface.
Furthermore in belt design, it is desirable to stagger the [cord
layer] endings in the edge regions of the belt by employing
[cord layers] of different widths. This gives a progressive
reduction in stiffness and minimized stress concentration at the
belt edge. Accordingly, the conventional design for truck tire
belts is for the widest [cord layer] to be the inner of the two low
[inclination] angle [cord layers] and the innermost high
[inclination] angle [cord layer] and the other low [inclination]
angle [cord layer] to be of similar widths. The belt may
optionally include a radially outermost and narrowest fourth
[cord layer] of low angle cords.
Gaudin col. 1, ll. 11-44. Applying the same representations used by
Farnsworth, we find that according to Gaudin, the conventional prior art tire
has the construction from innermost cord layer to outermost cord layer of
H/L/L′, wherein L is the widest cord layer and H and L′ are of “similar
widths.”
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