Resilient tires and wheels – Tires – resilient – Anti-skid devices
Reexamination Certificate
1999-02-03
2001-04-03
Maki, Steven D. (Department: 1733)
Resilient tires and wheels
Tires, resilient
Anti-skid devices
C152S209260
Reexamination Certificate
active
06209602
ABSTRACT:
TECHNICAL FIELD
This invention relates to a pneumatic agricultural tire for an industrial type tractor or like vehicle.
BACKGROUND ART
Farm tire designs for industrial service are classified as R
4
service. Overall R4 service is quite severe and typically involves high loads at a large degree of roading. The vehicles to which the tires are mounted typically are exposed to large amounts of debris, hard packed soil conditions and high load service conditions.
Often times the vehicle has a back hoe bucket or a front skid loader attached to the vehicle. The tires must traverse gravel and broken concrete and hard packed dirt normally. Occasionally the work site can get rain soaked requiring good traction in wet soil conditions.
These tires are generally relatively small and typically have a nominal rim diameter of 28″ (71 cm) or less. They generally have a nonskid depth at the centerline of the tire at approximately 1″ (2.54 cm). A typical tire may be a 19.5LR24 tire. This tire when produced in a radial construction will have a carcass with 3 to 4 plies of synthetic cord reinforcement. The cords generally are nylon or polyester. The carcass will further include four belts of high flex polyester, nylon or aramid. Historically, these tires have been all fabric reinforced in order to provide better ride and handling.
The most relevant prior art is Japanese Publication No. 57167802, the tire of this invention travels well on both good and soft roads. Its tread pattern consists of three regions with almost the same width. At the two side regions, lugs are arranged alternately on the tire circumference to form arrowhead pattern. They are at an acute angle to the tire equator. At the central region, independent long blocks are laid across the tire equator. Each block is placed on a line extended from the longitudinal centerline of one lug located on one of the side regions. The adjacent blocks face each other and overlap for a certain range but separated by a groove along the equator.
Another prior art document, U.S. Pat. No. 4,659,976), discloses a tire for use on a military vehicle, the tire has traction elements separated by straight grooves.
Yet another prior art, (German Patent No. DE 27 51 295 A1), discloses a farm tire having elongated lugs 6 spaced from the center of the tread and in at least one embodiment, the lugs 6 are separated by square blocks 9.
There has been a continual tradeoff in attempting to increase the aggressive offroad and tractor performance of these tires while maintaining the treadwear durability and ride requirements. The invention disclosed in this patent application teaches a novel tread that is both comfortable riding, long wearing while also achieving superior offroad traction.
DISCLOSURE OF THE INVENTION
SUMMARY
A pneumatic agricultural tire
20
for an industrial type tractor of like vehicle having a maximum section width (W), an axis of rotation, an equatorial plane (EP), centered between the maximum section width and being perpendicular to the axis, a casing having a belt reinforcement structure
26
and a carcass
21
reinforced with rubber coated cords, a rubber tread
32
disposed radially outward of the carcass
21
and belt
26
, the tread
32
being divided on each side of the equatorial plane into a first and second tread half, the tread has a pair of lateral edges
33
A,
33
B, the distance between the lateral edges defines the tread width. The tread
32
has an inner tread
34
and a plurality of tread lugs
40
,
50
projecting radially from the inner tread
34
.
The tread
32
has a plurality of central lugs.
50
and a plurality of shoulder lugs
40
. The plurality of central lugs
50
are arranged in a circumferentially continuous row
60
and extend across the equatorial plane (EP). Each central lug
50
preferably is similar in shape and in orientation relative to each circumferentially adjacent central lug
50
. Each central lug
50
has a leading end
51
and a trailing end
53
. The leading end
51
of each central lug
50
is located on an opposite side of the equatorial plane relative to the trailing end
53
of the same central lug
50
.
The plurality of shoulder lugs
40
are divided into first and second rows. One row
44
,
46
extends from each of the lateral edges
33
A,
33
B towards the equatorial plane of the tire
20
. The shoulder lugs
40
have an axially inner end
41
axially spaced from a leading end
51
and a trailing end
53
of the axially adjacent central lugs
50
. Preferably, the shoulder lugs
40
extending from each lateral edge
33
A,
33
B are similar in shape and have an overall lug length of 40% of the tread width. Each shoulder lug
40
is located within one tread half
32
A or
32
B.
The shoulder lugs
40
and central lugs
50
are axially spaced at the outer surface
58
of the lug
40
,
50
such that the axially inner ends
41
of the first and second rows
44
,
46
of shoulder the lugs
40
are axially aligned within each respective row
44
,
46
and the leading ends
51
and trailing ends
53
of the central lugs
50
are respectively axially aligned. A plane P
1
tangent to the axially inner ends
41
of the first row
44
of shoulder lugs
40
is spaced an axial distance d
1
from a plane C
T
tangent to the trailing ends
53
of the central lugs
50
. A plane P
2
tangent to the axially aligned inner ends
41
of the second row
46
of shoulder lugs
40
is spaced a distance d
2
from a plane C
L
, the plane C
L
being tangent to the leading ends of the central lugs. The distances d
1
and d
2
form two circumferentialy continuous straight channels around the periphery of the tread. In the preferred embodiment the distances d
1
and d
2
are equal and are about 5% of the tread width. The plane C
T
and C
L
are each located an axial distance of at least 5% of the tread width or more from the equatorial plane. Preferably the plane C
T
and C
L
are equally spaced from the equatorial plane a distance greater than 10%.
In one embodiment the shoulder lugs
40
of the first and second rows
44
,
46
are oppositely oriented and similarly inclined relative to the shoulder lugs
40
of the opposite row
44
,
46
. In this case, the tire tread
32
is a nondirectional tread having equal traction in both the forward and reverse direction.
In a second embodiment the shoulder lugs of the first and second rows are oppositely oriented and oppositely inclined relative to the shoulder lugs of the opposite row. In this case, the tire tread is directional and has a superior tractive capability in the forward direction when the tire is mounted such that the leading ends contact the ground first as the tire rolls. The tire in either case has a very open tread pattern for its application and when the tire is normally inflated and loaded the tread has a net-to-gross ratio of less than 35% preferably about 30%.
These tires typically have nominal rim diameter of 28″ (71 cm) or less and a tread lug height that is measured from the inner tread to the radially outer surface of the lug at the equatorial plane the lug height being an industrially standard R-4 lug height.
Each shoulder lug and central lug has a surface area centroid M. The centroid M of the first row shoulder lug, a central lug and a second row shoulder lug lie on a substantially straight line S
L
. S
L
is inclined in a range of 35° to 45° relative to an axial plane. In the nondirectional tire the shoulder lugs of the first and second row and the central lugs each have lug center lines intersecting the centroid M of the respective lugs. The lug centerlines are substantially aligned with the line S
L
. In the nondirectional tire each shoulder lug and central lug has a centroid M, the centroid of the first or second shoulder lug and a central lug lie in a substantially straight line S
L2
, S
L2
being inclined in the range of 35° to 45° relative to an axial plane. Each shoulder lug and central lug have a center line intersecting the centroids M of the respective lugs. The lug centerlines of the first shoulder lug and the central lug are substanti
King David L
Maki Steven D.
The Goodyear Tire & Rubber Company
LandOfFree
Industrial service agricultural tire does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Industrial service agricultural tire, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Industrial service agricultural tire will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2466029