Irrigation Tire

Abstract

A non directional pneumatic tire is provided for an agricultural irrigation system. The tire includes first and second side walls and a radially outer wall defining an internal inflation chamber. A non directional tread pattern is defined on the tire and includes a plurality of longitudinal protrusions positioned substantially parallel to a rotational axis of the tire. The longitudinal protrusions are arranged in first and second rows extending from the first and second side walls toward and across the equatorial plane of the tire. The longitudinal protrusions of the first and second rows circumferentially alternate with each other and there is a circumferential spacing between adjacent longitudinal protrusions at the equatorial plane so that no portion of one longitudinal protrusion circumferentially coincides with or overlaps another.

What is claimed is: 
     
         1 . A non-directional pneumatic tire for supporting an agricultural irrigation system, comprising:
 first and second sidewalls and a radially outer wall defining an internal inflation chamber;   a non-directional tread pattern defined on the tire and including a plurality of longitudinal protrusions positioned substantially parallel to a rotational axis of the tire;   the longitudinal protrusions being arranged in a first row of equally circumferentially spaced longitudinal protrusions extending from the first sidewall toward and across an equatorial plane of the tire and a second row of equally spaced longitudinal protrusions extending from the second sidewall toward and across the equatorial plane of the tire, the longitudinal protrusions of the first and second rows circumferentially alternating with each other so that each longitudinal protrusion of the first row is circumferentially located midway between two adjacent longitudinal protrusions of the second row, and there being a circumferential spacing between adjacent longitudinal protrusions at the equatorial plane so that no portion of one longitudinal protrusion circumferentially coincides with another longitudinal protrusion.   
     
     
         2 . The tire of  claim 1 , wherein the tread pattern has a relatively low rubber to void ratio over a tire width of less than about 20%. 
     
     
         3 . The tire of  claim 1 , wherein the tread pattern has a rubber to void ratio over a tire width in the range of from about 16% to about 20%. 
     
     
         4 . The tire of  claim 1 , wherein an aspect ratio of the tire defined as tire section height divided by tire section width is no greater than about 90%, thereby providing a relatively wide tire. 
     
     
         5 . The tire of  claim 1 , having a tire section width of at least 10 inches. 
     
     
         6 . The tire of  claim 5 , having an outside diameter of at least 40 inches. 
     
     
         7 . The tire of  claim 1 , having a tread pitch in the range of 10 to 25, the tread pitch being defined as the number of longitudinal protrusions in one of said first and second rows. 
     
     
         8 . The tire of  claim 7 , wherein the tread pitch is in the range of 15 to 21. 
     
     
         9 . The tire of  claim 7 , wherein an outside diameter of the tire is at least about 40 inches. 
     
     
         10 . The tire of  claim 1 , wherein:
 the radially outer wall has an inner tread defined thereon between the longitudinal protrusions; and   each longitudinal protrusion includes a contact surface and a protrusion side, each protrusion side including a first taper surface extending from the contact surface and a second taper surface extending from the first taper surface to the inner tread, the first and second taper surfaces extending along both longitudinal sides of each longitudinal protrusion.   
     
     
         11 . The tire of  claim 1 , wherein the tire comprises rubber and an anti-weathering agent, the anti-weathering agent comprising at least 8 parts per hundred parts of the rubber. 
     
     
         12 . The tire of  claim 11 , wherein the anti-weathering agent comprises 8-18 parts per hundred parts of the rubber. 
     
     
         13 . The tire of  claim 11 , wherein the anti-weathering agent is selected from the group consisting of wax, an anti oxidant, resin, an anti ozonant and combinations thereof. 
     
     
         14 . The tire of  claim 1 , wherein:
 the tread pattern further includes a circumferential protrusion spanning the equatorial plane, each of the longitudinal protrusions having a terminal end overlying the circumferential protrusion.   
     
     
         15 . The tire of  claim 14 , wherein:
 the terminal end of each longitudinal protrusion is enlarged circumferentially.   
     
     
         16 . A tire for use with a wheel to support agricultural irrigation equipment on a surface, the tire comprising:
 an axis;   a tire outside diameter of at least 40 inches and a tire axial width of at least 10 inches;   first and second sidewalls positioned substantially perpendicular to the axis;   a top layer circumferentially positioned around the axis and connecting the first and second sidewalls, the top layer including a non-directional tread pattern, the tread pattern including:   a circumferential lug positioned between the first and second sidewalls;
 a plurality of equally circumferentially spaced longitudinal lugs positioned substantially parallel with the axis, the longitudinal lugs being arranged in a first row extending from the first sidewall and a second row extending from the second sidewall, the longitudinal lugs including a lug contact surface, lug sides and a substantially spade-shaped terminal end terminating within the circumferential lug, each terminal end of each longitudinal lug of the first row extending past the terminal end of longitudinal lugs of the second row, each terminal end of each longitudinal lug of the first row being equally circumferentially spaced from adjacent terminal ends of longitudinal lugs of the second row, each longitudinal lug of the first row spaced from adjacent longitudinal lugs of the first row to define an inner tread, each longitudinal lug of the second row positioned opposite the location of an inner tread of the first row; and 
 the circumferential lug positioned to space the terminal end of each longitudinal lug radially away from the axis; 
   the top layer and sidewalls defining an internal chamber when positioned on the wheel, the internal chamber shaped to hold a gas; and   the tire being comprised of rubber and an anti-weathering agent wherein the anti-weathering agent includes a concentration of at least 8 parts per hundred parts of the rubber.   
     
     
         17 . The tire of  claim 16 , having a tread pitch in the range of 15 to 21, the tread pitch being defined as the number of longitudinal lugs extending from each of said sidewalls. 
     
     
         18 . The tire of  claim 16 , wherein the tread pattern has a rubber to void ratio over the tire axial width in the range of from about 16% to about 20%. 
     
     
         19 . The tire of  claim 16 , wherein an aspect ratio of the tire defined as tire section height divided by tire section width is no greater than about 90%. 
     
     
         20 . The tire of  claim 16 , wherein:
 the lug sides of the longitudinal lugs include a first taper surface extending from the lug contact surface and a second taper surface extending from the first taper surface to the inner tread, the first and second taper surfaces extending along both longitudinal sides and around the spade-shaped terminal end of each longitudinal lug.