Non-pneumatic tires for in-field irrigation systems
A non-pneumatic tire for a wheeled tower of an in-field irrigation system has a circular array of hollow cavities within the tire body. In cross-sectional planes lying normally of the rotational axis, each cavity has a circumferentially elongated cross-section of greater circumferential length than radial width. Bulbous and concavely rounded terminuses of each cavity impart a dumbbell shaped cavity profile that omits stress failure points. The cavity width tapers in an axially inward direction toward a midplane of the tire, where the cavity width is narrowest. In use, collapse of the cavity at its narrow midpoint squeezes accumulate mud out from the cavities in self-cleaning fashion. The outer circumference of the tire features sloped areas whose axial measure decreases toward the midplane. In use of the tire, the sloped areas draw mud inwardly toward the midplane and self-fill the ground beneath the tire, and thereby lessening overall rut formation.
1 . A non-pneumatic tire usable on a wheeled tower of an in-field irrigation system, said tire comprising:
a resiliently radially-compressible tire body having an outer circumference spanning circumferentially around a central rotational axis on which said tire body is rotatable; and
in circumferentially distributed relation to one another around said central rotational axis at a radial distance spaced inwardly from said outer circumference of the tire body, a circular array of hollow cavities disposed within said tire body;
wherein each hollow cavity in said circular array:
penetrates axially through the tire body and terminates in open outer ends at axially opposing sides of the tire;
in cross-sectional planes lying normal to said central rotational axis, has a circumferentially elongated cross-section featuring a length dimension that is measured in a direction of circumferential relationship to the central rotational axis, and that exceeds a lesser width dimension that is measured in a direction of radial relationship to the central rotational axis;
is dumbbell shaped in said elongated cross-section, and thus characterized by bulbously and concavely rounded terminuses at opposing ends of said elongated cross-section that are interconnecting by an intervening central region of the elongated cross-section that spans between the bulbously and concavely rounded terminuses, among the intervening central region measures narrower than each of the bulbously and concavely rounded terminuses in the width dimension, and measures longer in the length dimension than each of bulbously and concavely rounded terminuses measures in each of the length and width dimensions; and
is configured to undergo radial collapse at a radially narrowest part of the hollow cavity during movement of the hollow cavity through a ground-contacting under-center portion of a circular rotational path of the tire around the central rotational axis, and to thereafter radially re-expand to an uncollapsed state, and the bulbously and concavely rounded terminuses avoid creation of premature stress-failure points under ongoing cyclical collapse and re-expansion of the cavity.
2 . The tire of claim 1 wherein the width dimension of each hollow cavity is greater at the open outer ends thereof at the axially opposing sides of the tire body than at a midplane of the tire body that lies normally of the central rotational axis at a midway point between said axially opposing sides of the tire body.
3 . The tire of claim 2 wherein said width dimension of each hollow cavity tapers in an axially inward direction from each of the two axially opposing sides of the tire body toward the midplane thereof.
4 . The tire of claim 1 wherein the width dimension of each hollow cavity is tapered in an axially inward direction toward a midplane of the tire body that lies normally of the central rotational axis at a midway point between axially opposing sides of the tire body.
5 . The tire of claim 1 wherein the narrowest part of each hollow cavity resides at an axially central region thereof within which a midplane of the tire resides, and is configured to undergo full radial collapse during said movement of said hollow cavity through said ground-contacting under-center portion of said circular rotational path of the tire around the central rotational axis.
6 . The tire of claim 1 wherein the outer circumference of the tire body comprises a combination of raised treads and unraised regions situated between said raised treads, among which the raised treads reach radially further from the rotational axis that said unraised regions, and a radial measure of the outer circumference of the tire body, is greater at a portion of each unraised region that overlies the narrowest part of a respective hollow cavity than at other portions of said unraised region that overlie wider portions of the respective hollow cavity.
7 . The tire of claim 1 wherein said hollow cavities of circumferentially elongated cross-section in said circular array all reside at a same radial distance from the central rotational axis, and said circular array is a sole circular array of such cavities of elongated cross-section.
8 . The tire of claim 1 wherein said tire body is assembled from a plurality of tire segments each spanning a respective partial circumferential distance around said central rotational axis, each segment having a respective singular one of said hollow cavities therein.
9 . The tire of claim 1 in combination with a wheeled tower of an in-field irrigation system, on which said tire is installed.
10 . An improved method of operating an in-field irrigation system in an irrigated agricultural field, said method comprising:
using, on said in-field irrigation system, non-pneumatic tires of the type recited in claim 4 ;
during rolling movement of each non-pneumatic tire over the field, radially collapsing each tapered hollow cavity at a narrowest inner region thereof as said cavity moves through a ground-contacting bottom segment of a circular rotational path of the tire, and thereby squeezing accumulated mud out from the hollow cavities through open outer ends thereof at the axially opposing sides of the tire, whereby the tires perform self-cleaning of said hollow cavities.
11 . A non-pneumatic tire usable on a wheeled tower of an in-field irrigation system, said tire comprising:
a resiliently radially-compressible tire body having an outer circumference spanning circumferentially around a central rotational axis on which said tire body is rotatable; and
in circumferentially distributed relation to one another around said central rotational axis at a radial distance spaced inwardly from said outer circumference of the tire body, a circular array of hollow cavities disposed within said tire body;
wherein the outer circumference of the tire body has sloped areas, at each of which a radial measure of the tire body decreases in an axially inward direction moving toward an axial center of the tire body, and of which said sloped areas include first and second sets of sloped areas whose respective axially inward directions are measured from axially opposing sides of the tire body, and whose respective slopes of decreasing radial measure respectively start at said axially opposing sides of the tire body to draw mud inwardly from said axially opposing sides of the tire body toward the axial center thereof in order to self-fill the ground beneath the tire and reduce rut formation in the field of said in-field irrigation system.
12 . The tire of claim 11 wherein the outer circumference of the tire body comprises a combination of raised treads and unraised regions situated between said raised treads, among which the raised treads reach radially further from the rotational axis that said unraised regions, and each sloped area of the outer circumference occupies one of said unraised regions between two of the raised treads.
13 . The tire of claim 12 where the radial measure of the tire body, at each raised tread, is uniform over at least a partial axial span of said raised tread.
14 . The tire of claim 13 wherein the radial measure of the tire body, at each raised tread, is uniform over at least a majority axial span of said raised tread.
15 . The tire of claim 12 wherein the raised treads are arranged in a staggered tread pattern in which sequentially adjacent treads around the outer circumference of the tire body alternate between a first position adjacent a first side of the tire body and a second position adjacent a second side of the tire body, the first set of sloped areas reside adjacent the first side of the tire between the treads that reside in the first position, and the second set of sloped areas reside adjacent the second side of the tire between the treads that reside in the second position.
16 . The tire of claim 12 wherein each sloped area in the first set of sloped areas is separated from an adjacent sloped area in the second set of sloped areas by a raised central area where the radial measure of the tire body is greater than at inner ends of the sloped areas, and the respective slope of decreasing radial measure of each sloped area spans at least a majority of a shortest axial distance from one of the opposing axial sides of the tire to a radially tallest extremity of the raised central area.
17 . The tire of claim 16 wherein the radial measure of the tire body at said central area is uniform across at least a majority axial span of said central area.
18 . The tire of claim 16 wherein said radial measure of the tire body at said central area is uniform across an entire axial span of said central area.
19 . The tire of claim 16 wherein said raised central area coincides with an axial mid-zone of the tire where the width dimension of each hollow cavity is at a minimum.
20 . The tire of claim 11 wherein the respective slope of decreasing radial measure of each sloped area spans a majority of an axial distance from one of the opposing axial sides of the tire to a midplane of the tire body that lies normally of the central rotational axis at a midway point between said axially opposing sides of the tire body.
21 . An improved method of operating an in-field irrigation system in an irrigated agricultural field, said method comprising:
using, on said in-field irrigation system, non-pneumatic tires of the type recited in claim 11 ;
during rolling movement of each non-pneumatic tire over the field, using said first and second sets of sloped areas, as they move through a ground-contacting bottom segment of a circular rotational path of the tire, to draw mud inwardly toward a midplane of the tire to self-fill the ground beneath the tire and thereby reduce excessive rut formation in the field.