MOBILITY DURING A SHOW
A standard 8 wheeled air suspension rear trailer assembly transforms into the monster's rear tail caster wheel.

The ROBOSAURUS mobility concept utilizes the same steering principles used on the very agile SPYDER, Inc. of Houston, Texas line of hydraulic sod unloaders.

FIGURE 12. The highly mobile SPYDER sod unloader

Namely, each front leg has independent forward/reverse hydraulic wheel drive motors and a castered tail wheel assembly. In Robo's case, the left and right wheel drives are controlled using P-Q Control Inc.’s proportional heel/toe operated foot pedals

Pushing both toes down = straight ahead travel
Pushing both heels down = straight back up
Left toe down plus right heel down = tight right turn (a spin to the right)

 

FIGURE 12a. 4 foot Diameter Gun Turret Bearing.

This large bearing was required to carry the bending loads induced by the offset castor wheel. Bearing mount steel plates (1.5 inch thick) were first welded to the tail structure and to the rear trailer structure. The plates were next blanchard ground flat prior to drilling and tapping with a magnetic base drill. Lastly, the bearing was bolted to the plates.

 

FIGURE 12b. Tail Wheel Bearing Installation

Robosaurus co-inventors Robert Kubinski and Doug Malewicki (pointing at gun turret bearing location). The bearing is centered between the fore and aft rear axle sets.

 

FIGURE 12c. Finished Tail Wheel Structure

FIGURE 12d. Caster Wheel System

The following is the complete procedure to transform the tail wheel assembly from road (highway) configuration into its caster wheel (show) configuration:

1. Let air out of all rear trailer air springs. This lowers the tail.
2. Chain the forward axle set to the tail platform.
3. Fully inflate the rear axle set air springs. Then shut off air escape to these springs. This lifts the chained forward axle set 6 inches off ground which creates the caster wheel offset to the bearing center.
4. Unbolt the four corner Highway mode locking links that maintain exact trailer alignment.
5. When ready, the pilot activates a hydraulic cylinder that retracts a 1 1/2" diameter pin (in double shear) to allow the caster wheel to now freely rotate on the 4 foot diameter bearing.

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