Mould for a tire tread comprising concealed channels

A mould for moulding a tread of a tire, the tread having a thickness of material to be worn away and a tread surface adapted to come into contact with the road surface when the tire is running, said mould comprising:

• a moulding surface configured to mould the tread surface of the tread, said moulding surface comprising at least one moulding element formed of a blade and a bar, the blade being borne by the moulding surface of the mould so as to mould a sipe in the tread, the bar, borne by the blade forming an enlarged part of maximum width D, being configured to mould a channel in the tread, said channel itself being configured to form a new groove when the tread becomes part worn, this moulding element being such that each blade is delimited by two lateral faces forming between them a mean angle at least equal to 6 degrees and at most to 18 degrees, the blade having a maximum width LM at or proximate the moulding surface of the mould, this width gradually decreasing to be equal to a minimum width Lm at the connection with the bar, the minimum width Lm of the blade at the connection with the bar being at least equal to 0.2 times and at most equal to 0.4 times the maximum width D of the bar,
• wherein a plane that bisects the angle formed by the lateral faces of the blade makes an angle different from zero and at most equal to 6 degrees with a plane perpendicular to the moulding surface of the mould.

A mould for moulding a tread of a tire, the tread having a thickness of material to be worn away and a tread surface adapted to come into contact with the road surface when the tire is running, said mould comprising:

• a moulding surface configured to mould the tread surface of the tread, said moulding surface comprising at least one moulding element formed of a blade and a bar, the blade being borne by the moulding surface of the mould so as to mould a sipe in the tread, the bar, borne by the blade forming an enlarged part of maximum width D, being configured to mould a channel in the tread, said channel itself being configured to form a new groove when the tread becomes part worn, this moulding element being such that each blade is delimited by two lateral faces forming between them a mean angle at least equal to 6 degrees and at most to 18 degrees, the blade having a maximum width LM at or proximate the moulding surface of the mould, this width gradually decreasing to be equal to a minimum width Lm at the connection with the bar, the minimum width Lm of the blade at the connection with the bar being at least equal to 0.2 times and at most equal to 0.4 times the maximum width D of the bar,
• wherein the moulding element is formed of at least a first portion and a second portion, a plane that bisects the angle formed by the lateral faces delimiting the blade in the first portion being inclined to one side with respect to a plane perpendicular to the moulding surface of the mould, and to another side with respect to that same perpendicular plane in the second portion of the moulding element.