Resilient tires and wheels – Tires – resilient – Anti-skid devices
Reexamination Certificate
1999-02-10
2001-04-24
Maki, Steven D. (Department: 1733)
Resilient tires and wheels
Tires, resilient
Anti-skid devices
C152S902000
Reexamination Certificate
active
06220322
ABSTRACT:
The present invention relates to a pneumatic tire, more particularly to a tread portion improved in wear resistance.
BACKGROUND OF THE INVENTION
In pneumatic tires provided with a block type tread pattern comprising a number of blocks, uneven wear, e.g. so called heel/toe wear, shoulder wear and the like is liable to occur. The heel/toe wear is an uneven wear between the heel and toe or the rear and front edges of the blocks. The shoulder wear is an uneven wear between the tread crown region and tread shoulder region, in which the wear is larger in the shoulder region than the crown region.
IN THE DRAWINGS
FIG. 4
shows the ground contacting area of a block pattern tire which is viewed from the road side, wherein the direction and magnitude of movement of tread rubber at various points (a)-(p) during traveling towards the direction S are indicated by a vector.
In general, as shown in
FIG.4
, at the points on the blocks b
2
located in the shoulder region, the tread rubber moves toward the tire equator. However, at the points on the blocks b
1
in the crown region, the movements are in the circumferential direction rather than the axial direction. If the magnitude of movement is large, the wear is liable to become large.
OBJECTS OF THE INVENTION
It is therefore, an object the present invention to provide a pneumatic tire, in which uneven wear and wear resistance are effectively improved.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, a pneumatic tire comprises
a tread portion comprising a pair of shoulder regions and a crown region therebetween, each region provided with a longitudinal groove extending continuously in the tire circumferential direction,
the longitudinal groove being crossed by lateral grooves to form crossings and to define blocks on each side of the longitudinal groove,
the longitudinal grooves in the shoulder regions being provided near the crossings with tie-bars, each having a length Tc of from 10 to 40% of the average length of the longitudinal edges of two blocks axially adjacent to the tie-bar, each length measured along the longitudinal groove.
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
Embodiments of the present invention will now be described in detail in conjunction with the accompanying drawings.
REFERENCES:
patent: D. 57124 (1921-02-01), Githens
patent: D. 76886 (1928-11-01), Nesmith
patent: D. 78245 (1929-04-01), Wullenweber
patent: 1504694 (1924-08-01), Litchfield
patent: 5088536 (1992-02-01), Graas et al.
patent: 5211779 (1993-05-01), Tomioka et al.
patent: 5353854 (1994-10-01), Landers et al.
patent: 5439040 (1995-08-01), Iwamura et al.
patent: 5814169 (1998-09-01), Yamaguchi et al.
patent: 62-4608 (1987-01-01), None
patent: 62-4610 (1987-01-01), None
Birch & Stewart Kolasch & Birch, LLP
Maki Steven D.
Sumitomo Rubber Industries Ltd.
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