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AssigneeBridgestone/Firestone, Inc.
InventorsYaso Himuro, Bill J. Wallet, David M. Reep, Shawn L. Copeland, Yukio Yamakawa, Michael J. Ferraco
Estimating the term…
A tire tread has a total of four circumferential ribs and three circumferential grooves. The four ribs include two intermediate ribs and two outer ribs, and the three grooves include a center groove and two outer grooves. The two intermediate ribs are between the center groove and the two outer grooves, and the outer ribs are on the opposite sides of the outer grooves from the intermediate ribs. Rib cross slots and cross sipes extend outwardly from the outer grooves into the intermediate and outer ribs in herringbone patterns. The cross slots and cross sipes extend less than the full width of the ribs to provide the intermediate ribs with circumferential inner portions adjacent the center groove that are devoid of cross slots. These circumferential inner portions of the intermediate ribs have a plurality of circumferentially-spaced cross sipes that do not intersect the center groove. The rib cross slots are circumferentially-spaced a plurality of different distances to define a plurality of rib blocks having different lengths. Shorter rib blocks have a single cross sipe and longer rib blocks have double cross sipes. Shoulder cross slots intermediate the cross slots in the outer ribs overlap the outer rib cross slots by 25-35% of the outer rib cross slot length. The rib and shoulder cross slots have sloping closed end surfaces that intersect the outer surface of the tread at an angle of 35-42.degree.. Shoulder and outer rib cross sipes that are positioned opposite from the rib and shoulder cross slots do not intersect or overlap the rib or shoulder cross slots.
In a tire having a circumferential tread:
In a tire having a circumferential tread that engages a road surface with a footprint having a footprint width, said tread including a pair of road engaging intermediate ribs separated by a circumferential center groove, a circumferential outer groove on the opposite side of each rib in said pair of intermediate ribs from said center groove, said tread including a road engaging outer rib outwardly of each of said outer grooves, each said outer rib having a width that is substantially greater than the width of each of said intermediate ribs but less than two times the width of each said intermediate rib, a plurality of circumferentially-spaced cross slots extending into said intermediate ribs from said outer grooves, said cross slots extending less than the width of each intermediate rib to provide each intermediate rib with a circumferential outer intermediate rib portion adjacent each said outer groove that has said cross slots therein and a circumferential inner intermediate rib portion adjacent said center groove that is devoid of cross slots, said cross slots having intermediate rib blocks therebetween and being spaced-apart a plurality of different distances to provide said intermediate rib blocks with a plurality of different intermediate rib block lengths that include short intermediate rib block lengths and long intermediate rib block lengths, at least said short intermediate rib block lengths having a single cross sipe extending thereinto from said outer grooves, and at least said long intermediate rib block lengths having double cross sipes extending thereinto from said outer grooves.
In a tire having a circumferential tread that includes a pair of circumferential outer grooves and a road engaging outer rib outwardly of each of said outer grooves, road engaging intermediate ribs inwardly of said outer grooves, said intermediate ribs being separated from one another by a center groove that is circular circumferentially of said tire tread and does not zig zag or meander around the circumference of said tread and is located centrally of the width of said tread, said tread having a road surface engaging footprint with a footprint width that has footprint width boundaries, each of said outer ribs having an outer rib width that extends from one of said outer grooves to said footprint width boundaries, shoulder buttresses outwardly of said outer ribs beyond said footprint width boundaries, a plurality of circumferentially-spaced outer rib cross slots extending into said outer ribs from said outer grooves, said outer rib cross slots extending substantially more than one-half the width of each of said outer ribs but less than the entire width of each of said outer ribs, a plurality of circumferentially-spaced shoulder buttress cross slots in said shoulder buttresses, said buttress cross slots being located intermediate said outer rib cross slots and extending across said footprint boundaries into said outer ribs, said outer rib cross slots and buttress cross slots extending past one another in nonintersecting overlapping relationship with an overlap length that is between 25-35% of the length of said outer rib cross slots, a plurality of circumferentially-spaced intermediate rib cross slots extending from said outer grooves into said intermediate ribs that are located adjacent said outer grooves, and each of said plurality of intermediate ribs having a width that is less than the width of each of said outer ribs but greater than one-half the width of each of said outer ribs.
In a tire having a circumferential tread with a circumferential center groove and two circumferential outer grooves, each of said outer grooves being wider than said center groove;
In a tire having sidewalls and a road engaging circumferential tread with a pair of circumferential outer grooves, road engaging outer ribs outwardly of said outer grooves and having road engaging surfaces, shoulder buttresses between said sidewalls and said outer ribs, a plurality of circumferentially-spaced rib cross slots extending into said outer ribs from said outer grooves, a plurality of circumferentially-spaced shoulder buttress cross slots that are spaced circumferentially of said tread and extend transversely of said tread from said shoulder buttresses into said outer ribs intermediate said rib cross slots in circumferentially-spaced overlapping relationship to said rib cross slots, each of said shoulder buttress cross slots being longer than each of said rib cross slots, each of said outer ribs having a circumferentially extending circular slot that is circular circumferentially of said tread and intersects each of said rib cross slots and each of said buttress cross slots, each of said rib cross slots having a rib cross slot depth, each of said circumferential slots having a circumferential slot depth, each of said outer grooves having an outer groove depth, said circumferential slot depth being less than said rib cross slot depth, said rib cross slot depth being less than said outer groove depth, and said rib cross slots and shoulder cross slots having closed ends with end surfaces that intersect said road engaging surfaces at an angle between 35-42.degree..
In a tire having a circumferential tread:
In a tire having a circumferential tread that includes a pair of intermediate ribs separated by a circumferential center groove, a circumferential outer groove on the opposite side of each rib in said pair of intermediate ribs from said center groove, a plurality of circumferentially-spaced cross slots extending into said intermediate ribs from said outer grooves, said cross slots extending less than he width of each rib to provide each rib with a circumferential outer intermediate rib portion adjacent each said outer groove that has said cross slots therein and a circumferential inner intermediate rib portion adjacent said center groove that is devoid of cross slots, said cross slots having rib blocks therebetween and being circumferentially spaced-apart a plurality of different distances to provide said rib blocks with a plurality of different rib block lengths that include short block lengths and long block lengths, at least said short block lengths having a single cross sipe extending thereinto from said outer grooves, at least said long block lengths having double cross sipes extending thereinto from said outer grooves, and a plurality of circumferentially-spaced inner intermediate rib portion cross sipes in said inner intermediate rib portions of said intermediate ribs intersecting said single and double cross sipes and said cross slots and forming chevron patterns therewith.
Dependencies are inferred from the claim text.