Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C15/00—Tyre beads, e.g. ply turn-up or overlap
  • B60C15/02—Seating or securing beads on rims
  • B60C15/0233—Securing tyres without beads; Securing closed torus or tubular tyres
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60B—VEHICLE WHEELS; CASTORS; AXLES FOR WHEELS OR CASTORS; INCREASING WHEEL ADHESION
  • B60B21/00—Rims
  • B60B21/10—Rims characterised by the form of tyre-seat or flange, e.g. corrugated
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C3/00—Tyres characterised by the transverse section
  • B60C3/02—Closed, e.g. toroidal, tyres

Definitions

• the present invention concerns wheels for land vehicles and methods for moving such vehicles over support surfaces such as beach sand or irregular support surfaces such as rocky terrain.
• OMPI bearing capacity to retain such prior art tires on their rims and to ensure that such wheels can resist the torque applied to drive and brake such vehicles, the tire carcasses have typically been quite rigid and far less flexible than their inner tubes. Both tube type and tubeless tires have been inflated to a rather high operating pressure, typically well in excess of 25 pounds per square inch. When such prior art wheels are mounted on a vehicle and subjected to an axle load, the tire flattens very slightly and, in general, retains an exterior appearance quite similar to that of an unin- flated, unloaded wheel.
• Such prior art wheels are admirably suited for use on vehicles which operate over relatively hard, even support surfaces.
• the performance of the prior art wheel often is less than satisfactory.
• the contact area between the prior art tire and the underlying support surface is so small that the pressure per unit area is extremely high on the underlying support surface, which often causes the wheels of the vehicle to sink at least partially into soft support surfaces such as beach sand.
• the relatively hard, unyielding nature of such prior art tire carcasses and their high inflation pressure make it difficult for the tire to yield to obstacles in its path so that the vehicle can go forward with a minimum of applied power.
• large expensive wide track tires have been used in self-powered vehicles to facilitate their movement over soft and irregular surfaces due to the increased contact area of the wide track tire.
• the primary object of the present invention is to provide an improved wheel for land vehicles which will facilitate moving such vehicles over soft or irregular support surfaces with a reduced effort compared to prior art wheel assemblies.
• a further object of the invention is to provide an improved method for moving land vehicles over such surfaces.
• a wheel in accordance with the invention comprises a tire supporting rim having a substantially cylindrical outer surface for engaging a tire and a central opening for engaging an axle of a vehicle.
• a low pressure tire which engages the cylindrical outer surface and comprises a thin-walled torus of elasto- meric material.
• the wall of the tire is substantially free of reinforcing elements which would limit its elasticity and flexibility.
• "torus” means a surface or solid shaped like a doughnut and formed by revolving a circle about a line in the plane of the circle without intersecting the line with the circle.
• the torus-like tire has an inner diameter surface engaging the rim and conventional inflation stem or inflation needle valve for inflating the tire to a low pressure, preferably less than 10 psi.
• the outer diameter surface of the tire directly contacts the underlying support surface so that the tire, when loaded, will deform or flatten substantially where it contacts soft or irregular support surfaces, thereby facilitating movement of an associated vehicle over such surfaces.
• the rim of the wheel comprises a pair of oppositely, axially extending support flanges
• these support flanges comprise radially outwardly flaring conical portions and axially extending cylindrical flanges extending from the conical portions, both of which engage the tire as it flattens.
• the rim may be integral or separable into axially extending halves and the tire may comprise a radially inwardly extending flange or plurality of tabs captured between such halves in the assembled wheel.
• the axial length of the rim preferably is greater than or equal to twice the undeformed radius of the circle of revolution of the torus but no greater than T ⁇ times this radius.
• the diameter of the cylindrical flange portions preferably is greater than the diameter of the inner diameter surface of the .tire but not more than three times larger.
• a vehicle is provided with at least one wheel comprising a tire supporting rim with a substantially cylindrical outer surface for engaging a tire and a central opening for engaging an axle.
• a low pressure tire is mounted on this rim, the tire comprising a thin-walled torus of elastomeric material, the tire having an inner diameter surface for engaging the rim, means for inflating the torus to a low pressure and an outer diameter surface for directly contacting the underlying support surface.
• Such a tire is inflated to allow pressure sufficient
• OMPI to allow the tire to deform or flatten substantially when the torus contacts soft or irregular support surfaces as a vehicle moves across such surfaces.
• Fig. 1 shows a sectional elevation view of a wheel according to the present invention, indicating the substantially flattened configuration assumed by the torus-like tire when a load is applied to the assembly.
• Fig. 2 shows a side elevation view of a wheel according to the invention, as seen from the left in Fig. 1.
• a wheel 10 according to the invention comprises a tire supporting rim 12 made up from a pair of virtually identical rim halves 14 and 16.
• the halves comprise central cylindrical portions 18, 20 having substantially cylindrical outer surfaces 22, 24 of diameter d, for engaging the low pressure tire according to the invention.
• Central bores 24, 26 are provided in each half for receiving a vehicle axle 28, illustrated in phantom.
• cylindrical portions 18, 20 are joined to oppositely, axially extending support flanges 30, 32 having radially outwardly flaring conical portions 34, 36 with cone angles ⁇ in the range of 20 degrees to 80 degrees.
• OMPI 38 are joined to conical portions 34, 36.
• Each cylindrical flange has a diameter D which is larger than but preferably no more than three times the length of diameter d, in order to prevent the low pressure tire from working its way from rim 12 during use.
• a cylindrical spacer 40 is received in a pair of oppositely facing recesses 42, 44 provided at the inner ends of cylindrical portions 18, 20.
• the halves of rim 12 are ' joined by suitable fasteners such as bolt and nut pairs 46 which extend through cylindrical portions 18, 20, as illustrated.
• a tire comprises a thin-walled torus 50 of an elastomeric material such as 30% EPDM rubber with furnace black pigment, the rubber having the properties of Shore A 50, tensile strength 1700 psi, modulus of elasticity at 300% elongation, 500 (rheometer) tear strength 150 lbs. with B die.
• the thickness of the torus was approximately 0.125 inch
• the radius r of the circle of revolution of the torus was approximately 3.0 inches
• the overall diameter D' of the torus was approximately 17.5 inches.
• the inner diameter surface 52 of torus 50 engages the outer surfaces of the rim 12 as previously indicated and has approximately the same diameter.
• diameter d was approximately 8.75 inches and diameter D was approximately 13.75 inches.
• the axial length of the assembled rim 12 is greater than or equal to twice radius r but no greater than IT times radius r, in order to provide adequate contact
• Tire 48 is provided with a means 54 for inflation to a low pressure, such as a conventional valve stem member which extends through a hole in conical portion 34, or an inflation needle valve of the type used in basketballs, for example.
• a low pressure such as a conventional valve stem member which extends through a hole in conical portion 34, or an inflation needle valve of the type used in basketballs, for example.
• torus 50 preferably is inflated to no more than 10 psi in order to ensure that the tire will flatten or deform in the manner illustrated and thereby provide sufficient contact surface to permit an associated vehicle to move easily over soft or irregular support surfaces. Pressure as low as 3 psi has proven suitable for many applications. Such support surfaces are contacted directly by the outer diameter surface 56 of torus 50.
• Tire 48 can be made by conventional extruding and molding techniques used in the rubber industry to make inner tubes, bladders and the like.
• a central, radially inwardly directed flange 58 or a similarly oriented plurality of tabs may be captured between the inner ends of cylindrical portions 18, 20 to provide additional assurance that the tire will not move from its rim.
• reinforcing strands or cords 60 may be provided in the wall of torus 50 in the area where the tire engages its rim, in order to provide additional strength at that location; however, a significant advantage of the present invention is that the use of such reinforcements is not necessary at any place in the tire and is particularly undesirable in the wall adjacent contact surface 56 since such reinforce ⁇ ments would limit the ability of the tire to flatten or deform in the preferred manner.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Tires In General (AREA)

Applications Claiming Priority (1)

Publications (2)

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ID=22182047

Family Applications (1)

Country Status (7)

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Citations (2)

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• 1984
  • 1984-02-17 BR BR8407290A patent/BR8407290A/pt unknown
  • 1984-02-17 WO PCT/US1984/000222 patent/WO1985003674A1/en not_active Application Discontinuation
  • 1984-02-17 EP EP19840901151 patent/EP0172808A4/de not_active Withdrawn
  • 1984-02-17 DE DE19843490658 patent/DE3490658T1/de not_active Withdrawn
  • 1984-02-17 JP JP84501171A patent/JPS61501384A/ja active Pending
  • 1984-02-17 GB GB08524575A patent/GB2165499B/en not_active Expired
• 1985
  • 1985-10-16 SE SE8504837A patent/SE8504837L/ not_active Application Discontinuation

Patent Citations (2)

Non-Patent Citations (1)

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