WHEELIFT SYSTEMS

Utilizing the Uniload Suspension for Precision Docking

The combination of Wheelift’s all-wheel electric drives, fluid suspension, and independent on-center rotation of each axle assembly provides the foundation for true precision alignment.  Aside from effortless steering under full load, precision alignment is one of the key root capabilities of the WHEELIFT transporter technology.   When aligning huge components in assembly operations, the transporter(s) are put into a “creep speed” mode. Major changes in direction, such as moving into a near touch position and then having to move a slight amount laterally are the norm. In such an instance, when the operator selects “Lateral” mode the programming allows only half the axles to rotate, while the remaining axles stay fixed, eliminating unwanted movement that might otherwise occur if all axles rotated at once.

Typically, an operator will maneuver the load within a few feet of its final alignment position, and then select the “Creep Speed” travel mode.   All directions of travel are then dramatically reduced in speed to allow minute position corrections.  To observe these motions it is common to attach dial indicators in all planes to monitor the exact location requirement.  The operator can lightly “bump” the control to move as little as one thousands of an inch at a time.  For tooling application where the locating speed is more critical, mechanical stops and engagement pins are recommended:

• Shot Pins: For relatively accurate position ability, a reasonably large diameter vertical sliding shaft (normally with a tapered and bull nosed end) is inserted into a matching socket in the floor and the transporter is then lowered to floor contact. Adjustable pads on the base of the transporter can come done onto reference plates in or on the floor to establish the Z relationship.
• Shallow Taper Pads: Shallow tapered pads that are precision placed in the floor can provide a self-cleaning interface with the transporter.  In a docking position, the shallow tapered pads point up; let other traffic, including the transport, to drive over them without significant difficulty.  Typically there are two taper pads with matching tapered sockets in the transporter base.  It is desirable to make the sockets in the transporter adjustable in X, Y, and Z.   Flat plates take up the opposing two corners of the transporter.

Bumpers:  Elastomeric bumpers can be used effectively for relatively close alignment.  If the alignment is only parallel, the transporter eases into contact and then applies enough force on the drive motors to assure the desired force alignment. If X AND Y alignments are required, then a vertical taper in the pads can accommodate a matching protrusion on the transporter.  Z-alignment pads can also be considered.

There is much more that can be written and information that can be transferred, but it is beyond the scope of this overview presentation.  The nuances of how to take full advantage of all of UNILOAD’s  and SYNCHROSTEER’s unique capabilities , while all relatively simple and practical, are foreign to the norm of machine design.  It is easy to misunderstand various functionalities, because they tend to be interdependent on each other.  Something that seems obvious during a cursory examination may have interconnecting facets that can be overlooked or dismissed unwittingly.

The WHEELIFT website contains a wealth of information that needs to be carefully studied and revisited often during a potential customer’s initial examination phases.

 

 

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TRADEMARKS

The following terms that are used through this website: Wheelift^®, Uniload^®, SynchroSteer^®, StackAxle^®, TrackAxle™ and OmniAxle^™ are all trademarks that are exclusively licensed to Doerfer Companies.