Portal box

#The invention relates to a novel portal box construction for use in light off road vehicles.

#Off road vehicles in the form of ATV's (all-terrain vehicles) and UTV's (utility task vehicles) are produced by numerous manufacturers. Purchasers and users of these vehicles frequently desire to fit them with larger tires to give them greater agility in traversing rough terrain. To fit larger tires on these vehicles, it is common to install a lift kit to raise the vehicle body to make room for the larger tires and to increase ground clearance. Typically, a lift kit will adversely affect constant velocity (CV) joint angles and necessitate replacement of the original equipment axles, including CV joints. Even with these upgrades, steering geometry can be compromised and bump steer, for example, can be introduced. Still further, the final drive ratio measured as available force at the thread surface of the oversize tires is reduced in proportion to the size increase. The foregoing reveals a need for an aftermarket system to mount oversize wheels on off road vehicles that avoids the disadvantage of ordinary lift kits.

#The invention provides a portal box system for light off road vehicles that is simple, low in cost, and readily adapted for use on vehicles of different manufacturers. The disclosed portal box system comprises a universal backing plate and a narrow profile two-part housing in which is mounted a torque and height increasing gear train. The same backing plate with proper brackets attached can be used at all four wheels of a specific vehicle and with different sets of brackets on several different vehicles. The same left and right housings are used for front and rear wheels of a vehicle to which the system is applied. The same gear train can be used at all of the wheels and only the input gear may be modified to suit a particular brand of vehicle.

#FIG. 1 is a perspective view of a light off road vehicle to which the invention is applied;

#FIG. 2 is a somewhat schematic exploded isometric view of a portal box system employing the invention;

#FIG. 3 is a somewhat schematic cross-sectional view at one axle of a portal box system constructed in accordance with the invention;

#The invention is useful in lifting the chassis and increasing the wheel torque of light off road four-wheel drive vehicles such as the UTV illustrated in FIG. 1. The illustrated vehicle is originally manufactured by John Deere and marketed as a Model RSX 850i. It will be appreciated by those skilled in the art that the invention is applicable to vehicles of other manufacturers.

#The invention provides a portal box system, available as a kit, that replaces a vehicle's original wheel hub assemblies. The kit can include four portal boxes 10 and associated backing plates 11. FIGS. 2 and 3 illustrate a typical portal box 10 and backing plate 11. The backing plate 11 at each wheel 12 (FIG. 1) can be identical or essentially identical. Each backing plate 11 is provided with upper and lower mounting brackets 16, 17. Preferably, the backing plate 11 is a steel plate, for example, 1/4 inch thick. The brackets 16, 17, made of 1/2 inch steel plate, for example, are attached to the plate 11 preferably by welding.

#Referring to FIG. 4, the upper bracket 16 can have a hole 18 for attaching an upper ball joint 19 and a hole 20 (FIG. 2) for attaching a steering rod end 21. Similarly, the lower bracket 17 has a hole 22 for securing a lower ball joint stud 23.