WHEELIFT TRANSPORTERS

A New Generation in Ultra Low-Deck, Tandem Operating, All-Wheel Drive, Multiaxle, Heavy Transporters

Wheelift Systems specializes in very heavy capacity in-plant tandem operating transporters that are normally referred to as IP-SPMTs (The acronym for In-Plant Self-Propelled Modular Transporters).

Wheelift builds a revolutionary line of multiaxle transporters in self-loading, operator driven transporter configurations that have full tandem operating capability.  Wheelift heavy transporters are designed for loads ranging from 60 tons to several hundred tons and provide entirely new capabilities for heavy load moving systems for in-plant heavy assembly systems that have never before been available to industry.  Two to four or more of these heavy load transporters can work together in tandem while moving freely over any type of floor surface, including ramps and in-floor rail tracks.

The electric motor driven Wheelift transporters have unlimited carrying capacity and ultra low-deck profiles for self-loading. The transporters are fully self-propelled to allow travel throughout the plant, including between buildings and to remote test areas.  This new multiaxle heavy moving system technology expands the size and types of heavy machinery products industry can now build within their existing facilities.

The new generations of Wheelift heavy load moving transporters are actually quite amazing.  These heavy move solution transporters are fully self-contained and typically have overall flat-top deck-heights of less than 19 inches.  As shown on the right, in a “headless” configuration and with their ultra low deck heights, they can enter and exit stand-supported machinery from ANY direction.  With up to eight inches of vertical travel, these transporters can lift and carry any machinery where support stands provide 20 inches or more of drive-through clearance under their frames.

Initially, Wheelift transporters were available only in hydraulically powered configurations with LP gas engines in raised engine compartment.  Wheelift now concentrates on building electrically driven* ultra-low profile, all-wheel drive, transporters powered by LP or diesel engine/generator systems with the option to also operate on shore power.  While battery operated systems have been the norm across industry for conventional lighter applications, the move to engine-generated power dramatically expands the operational parameters and system capacities for both in-door and outdoor operations. Click here to view 6 min video clip.

For companies that build a wide range of very heavy product sizes, they are often best served by using two, three, or four transporters that operate in tandem.  Products being assembled are typically raised on support stands that provide 20 inches or more of “tunnel space” for transporter entry. If the products are physically large enough to require more than one transporter, the additional transporters will be driven under and be carefully positioned to be parallel to each other with the axles all aligned on matching centerlines.  Careful attention to alignment assures that whichever transporter that becomes the “Master” unit, it can easily control the exact wheel geometry of each of the tandem operating “slave” transporters. 

The current generations of Wheelift transporters are typically “headless”.  That is to say, their engine/generator and all of the control machinery are buried below the 19 inches in overall transporter height.  This unique capability allows an ultra-low overall transporter height.  In the headless configuration, the transporters can enter or exit from under the load in any direction.  The transporters typically have 6 inches of vertical lift capability to accommodate lift-and-carry operations, as well as provide the needed individual axle compliance to handle severe undulations and irregularities in the factory floors and yard surfaces.  Ramps often need to be negotiated when moving in and out of manufacturing spaces.  The amount of available lift determines the severity of ramp conditions that can be negotiated.

Current electrically driven all-wheel drive Wheelift transporters may have six, ten, even twenty or more axle assemblies and every wheel will be independently driven.  The onboard SynchroSteer® PLC based computer handles the complexity of “differential” steering, by controlling the individual motor speeds and direction that provide the vehicle’s fully omni-directional travel capabilities.

Typically every axle assembly under the transporters will have wide-faced solid urethane tires on each end of laterally articulating axles.  This arrangement allows the tires to load equally on sharply varying floor surface slopes and irregularities.  Further, each axle has a vertical travel center column that provides fluid equalizing suspension across every axle in the system, as well as providing the lift for self-loading. The fluid lifting center column is the key to allowing independent on-center rotation of each axle for the transporter’s all-directional travel capability.

Whether needed or not for the particular application, the omni-directional travel capability is inherent to the basic functionality of this system.  Neither Wheelift’s heavy moving system AGVs nor transporters can function without it. For instance, a heavy load moving transporter carrying a 100-ton load may only need to drive straight or make relatively long radius turns, and have no requirement to move laterally, rotate on-center, or make very sharp radius turns; or even need to lift up and down, yet it must have all of those capabilities to equally share the load across every tire in the system.  To avoid crushing or torsional damage to floors and equipment, that capability can only affectively be accomplished with a system that absolutely assures that every tire is seeing only its share of the load, regardless of minor or major undulations and other variations in the floor surfaces.  Those capabilities allow heavy transporters to travel over relatively thin and weak floor systems without the damaged caused from or to conventional wheel systems.  For relatively light loads, equalizing suspension is less critical, but as the load increases, the need for full equalizing suspension increases exponentially.

The practicality of when and where consideration of a wheelift heavy load moving transporter or AGV can be justified is whether the desired load weights are too heavy for conventional equipment.  After a careful evaluation of why conventional heavy trailers, overhead cranes, machinery moving “skates”, air bearings, or in-floor rail systems CAN NOT do the job, only then should one seriously consider a Wheelift solution.  If there are compelling reasons why conventional handling means will not work, then it may well be possible to cost-justify a dramatic jump in initial system cost.  If price is more important than functionality, then the Wheelift technology will not be applicable to that application.   Generally speaking, this multiaxle, heavy capacity, tandem operating, self-loading, transporter technology only applies to loads that have to move often and the requirements are so complex that conventional means will not allow the type of maneuverability needed.