Tire with improved traction

Abstract

The present invention concerns a tire (10) comprising a tread (11) provided with a base surface (14) and with a plurality of ribs (12), each rib (12) being provided with a front wall and a rear wall, wherein, on the front wall of the rib (12), under a top portion (13) of the front wall, a shaped profile (15) is present, with a base in the portion of the tread (11) comprised between the front wall of the rib (12) and the adjacent rib, height equal to a portion of the overall height of the front wall of the rib (12) and a length that extends in the transverse direction with respect to the height of the rib (12), characterised in that said shaped profile (15) has a section that defines at least one flat surface (17) of the shaped profile (15) which is parallel, or inclined at an angle α up to 20°, with respect to the surface of the head (16) of the rib and which is joint to said top portion (13) of the front wall of the rib (12) by means of a connecting surface (18), at least one sharp angle (19) of the shaped profile (15) and at least one front wall (23) of the shaped profile (15), which is joint to said base surface (14) of the tread (11) by means of a connecting surface (21).

1 - 9 . (canceled) 
     
     
         10 . Agricultural or forestry tire ( 10 ) comprising a tread ( 11 ) provided with a base surface ( 14 ) and with a plurality of ribs ( 12 ), each rib ( 12 ) being provided with a head ( 16 ), a front wall ( 13 ) and a rear wall ( 25 ), wherein, on the front wall ( 13 ) of the rib ( 12 ), under a top portion ( 13 ′) of the front wall ( 13 ), a shaped profile ( 15 ) is present, with a bottom of the shaped profile ( 15 ) in the portion of the tread ( 11 ) comprised between the front wall ( 13 ) of the rib ( 12 ) and the adjacent rib, height equal to a portion of the overall height of the front wall ( 13 ) of the rib ( 12 ) and a length that extends in the transverse direction with respect to the height of the rib ( 12 ), and wherein said shaped profile ( 15 ) is not present on the rear wall ( 25 ) of the rib ( 12 ), wherein said shaped profile ( 15 ) has a section that defines at least one flat surface ( 17 ) of the shaped profile ( 15 ), wherein said flat surface is joined to said top portion ( 13 ′) of the front wall ( 13 ) of the rib ( 12 ) by means of a connecting surface ( 18 ), and wherein the shaped profile ( 15 ) comprises at least one sharp corner ( 19 ) and a front wall ( 23 ) which is joined to said base surface ( 14 ) of the tread ( 11 ) by means of another connecting surface ( 21 ), characterized in that said flat surface is parallel, or inclined at an angle α up to 20°, with respect to the surface of the head ( 16 ) of the rib ( 12 ) and the width of said flat surface ( 17 ) of the shaped profile ( 15 ) in the middle portion of the rib ( 12 ) and the shaped profile ( 15 ) is obtained by addition of material to the front wall ( 23 ) of the rib ( 12 ). 
     
     
         11 . The agricultural or forestry tire ( 10 ) according to  claim 10 , characterised in that said top portion ( 13 ′) of the front wall ( 13 ) of the rib ( 12 ) is inclined at an angle β comprised between 10° and 30° with respect to the radial direction. 
     
     
         12 . The agricultural or forestry tire ( 10 ) according to  claim 10 , characterised in that said flat surface ( 17 ) of said shaped profile ( 15 ) is located at a height comprised between 1 mm and 9/10 of the overall height of the rib ( 12 ). 
     
     
         13 . The agricultural or forestry tire ( 10 ) according to  claim 12 , characterised in that said flat surface ( 17 ) of said shaped profile ( 15 ) is located at a height comprised between ¼ and ¾ of the overall height of the rib ( 12 ). 
     
     
         14 . The agricultural or forestry tire ( 10 ) according to  claim 10 , characterised in that the width ( 22 ) of said shaped profile ( 15 ), from the sharp corner ( 19 ) to an intersection where the connecting surface and the top portion of the front wall meet, is comprised between 1 mm and 9/10 of the distance between the front wall ( 13 ) of the rib ( 12 ) and the rear wall ( 25 ) of the adjacent rib ( 12 ), at the height of said shaped profile ( 15 ). 
     
     
         15 . The agricultural or forestry tire ( 10 ) according to  claim 10 , characterised in that the width ( 22 ) of said shaped profile ( 15 ), from the sharp corner ( 19 ) to an intersection where the connecting surface and the top portion of the front wall meet, is comprised between ½ and ⅛ of the width of the head ( 16 ) of the rib ( 12 ). 
     
     
         16 . The agricultural or forestry tire ( 10 ) according to  claim 10 , characterised in that said shaped profile ( 15 ) has a section with steps, i.e. defines a plurality of flat surfaces of the shaped profile ( 15 ), a corresponding plurality of sharp angles and front walls of the shaped profile, wherein said steps have a height and width equal to or different from each other. 
     
     
         17 . The agricultural or forestry tire ( 10 ) according to  claim 10 , characterised in that the surface of said shaped profile ( 15 ) has a different color from the rest of the tire.