Abstract:
A lightweight axle assembly may include a bracket at each end thereof for receiving a mount at one of a plurality of positions thereon. The mount may include a standoff for spacing an actual wheel assembly a suitable distance from the bracket. The axle may be formed to include a beam for suitable cross section including I-beams, channels, or boxes, as well as cylindrical tubes. Wheels may be mounted to spindles rigidly attached, to driving axles contained within the axle assembly, or to kingpins secured to the mounts. The axle may be adjusted to accommodate a broad range of suitable, relative, distances between the mounting surface (top or bottom of the axle end) and the center line of a wheel assembly associated with the axle. Forged mounts may be manufactured to accomplish structural objectives. Meanwhile, areas of less stress may be fabricated from lighter materials of various unconventional configurations.

Description:
BACKGROUND  
         [0001]    1. The Field of the Invention  
           [0002]    This invention relates to equipment for trucks and, more particularly, to novel systems and methods for providing adjustable axles for trucks.  
           [0003]    2. The Background Art  
           [0004]    Highway construction and maintenance is a matter of substantial concern to local, state, and federal governments. Road construction has always been an expensive proposition. Roads constructed using modern knowledge, methods, and technology have greatly improved the load-bearing capacity of vehicles traveling over those roads.  
           [0005]    Specific limitations exist on loading of vehicle axles. It is well established that bridges are designed to carry specific weights. However, in actual bridge design, several additional, localized factors exist. For example, bridges may have one or more surfacing materials, such as concrete or asphalt. The surfacing materials may be designed in various compositions to support various loads and provide predictable durability. However, underlying a bridge or road surface is a structure of specific members each designed for supporting a particular maximum force or load.  
           [0006]    Bridges in various parts of a roadway system have varying weight-carrying capacities. A truck having weight over some number of axles, must also have those axles distributed across a suitable length of the bridge in order to distribute the load of the truck properly over the individual structural members of the bridge.  
           [0007]    Thinking in terms of a truck, not as a truck, but as a series of axles, each bearing a load, one sees another important factor in the mutual design criteria between vehicles and roadways (e.g. bridges). That is, axles cannot be separated from the truck. The truck has a length; therefore, axles cannot be completely separated from each other. Therefore, all of the axles of the truck will pass over the bridge together. The truck has to distribute axles over some maximum length.  
           [0008]    Moreover, the construction of all bridges, streets, highways and roads provides for specific limitations on sustainable loads and the like. For example, just as building construction must start far below the surface level of the earth to support a foundation, many road beds must be deeply laid to provide acceptable sustainable loads. Above a road bed are laid various types and grades of materials. Ultimately, a surface material is provided on which vehicles roll directly.  
           [0009]    Pneumatic tires, in addition to improving a vehicle&#39;s ability to absorb shocks from the roughness of a surface, distribute the load of the vehicle over a surface area of a road surfacing material. Tire pressures relate directly to the distortion of a tire in order to present a certain amount of area onto a road for supporting the weight of the vehicle. For example, a four thousand pound vehicle having a total of fifty square inches of tire surface to the road must have a tire pressure of approximately twenty pounds per square inch to support the load. To support the same load or weight of a vehicle at forty pounds per square inch only twenty-five square inches of tire tread must be in contact with the road. Thus, local pressure on a road surface may be controlled, to a certain extent, by the inherit limits on tire pressures.  
           [0010]    The distance between a vehicle&#39;s axles is another factor in load distribution on a road bed. For example, two axles spaced relatively closely together will produce more load in a road bed than the same two axles, carrying the same loads, but spaced further apart. Thus, axle location may be very important in determining the local force presented on a bridge or a road bed by a particular axle. In this context, an axle may be used to refer to the axle itself, or to the axle and tires as they represent force application to a road bed from a vehicle supported thereby.  
           [0011]    The regulated carrier industry includes many types and classes of trucks. Trucks require both operable hardware and regulatory compliance. Trucks must comply with weight and dimensional limits for roads and especially bridges. Meanwhile, unnecessary wear is avoidable if unused portions, such as unneeded auxiliary axles, of a truck may be disengaged. For example, the basic structure of a truck includes a steering axle and a drive axle mounted to a frame supporting a cab and a bed. Drive wheels may be arranged as duals, tandems, or dual tandems.  
           [0012]    In certain circumstances, auxiliary axles may benefit a truck. Auxiliary axles provide load-bearing capacity that may be installed to operate permanently or selectively. Auxiliary axles may be positioned to lead the drive wheels, follow the drive wheels, or trail the entire vehicle. Often the requirement to selectively distribute the load on road beds and bridges drives the positioning of auxiliary axles. Suspension systems may vary depending upon the mounting arrangement of any axle on a truck. Moreover, axles that must be engageable selectively may require their own particular adaptations to meet with the manufacturer&#39;s specifications for the frame of the truck.  
           [0013]    Trucks today may be manufactured to have tandem axles spaced a comparatively long distance apart, as compared with trucks of previous years. Also, many trucks now carry auxiliary axles that can be engaged for distributing a load along a different length of the truck. For example, long truck bodies or trailers may have wheels located nearer the front end, rather than leaving the entire weight distributed between a front axle and a rear axle or between a tractor and a pair of closely spaced tandem axles at the rear.  
           [0014]    Auxiliary axles are often added to concrete mixer trucks to accommodate limitations on bridge weights. Also, auxiliary axles may be added to accommodate the large differential load between an empty truck and a loaded truck. Thus, auxiliary axles may be engaged for a limited time, only while a vehicle is loaded and is traveling on a road. At a work site, a truck may not need auxiliary axles as a support for the vehicle itself, and may disengage them.  
           [0015]    Thus, heavily loaded trucks having changes in load actually applied thereto, may need auxiliary axles. Those axles need to be distributed along a maximum length, and may need to be distributed along the vehicle itself. To protect roadways, to satisfy bridge weight limitations, and to support substantial loads, auxiliary axles may be used in vehicle construction.  
           [0016]    Truck manufacturers may regard axles of all types as materials. That is, a truck manufacturer may simply purchase axles from a suitable, available supplier. A truck design may be built to accommodate the particular dimensions of a preferred or suitable axle available from a known manufacturer. Not every truck is, however, custom designed. Often, a manufacturer or purchaser of a truck may desire to install a nonstandard axle, such as an auxiliary axle, in order to satisfy a particular need of a particular customer. The customer&#39;s needs may be driven by the task to be performed by the truck and the specific limitations on loading of axles applicable to the geographic region in which the truck will be operated.  
           [0017]    Inventory is a perennial problem for manufacturers. If a manufacturer produces a comparatively broad range of designs of trucks, a correspondingly broad range of axle designs may be required. Many designs are sensitive to axle height, as compared to truck frame height. The required suspension system mounting the axle assembly to a truck frame must also be taken into consideration.  
           [0018]    Accordingly, it would be an advance in the art to reduce inventories and design commitments by providing both principal and auxiliary axles adaptable to fit a plurality of vehicle heights. Moreover, it would be an advance in the art to provide an axle assembly that could be inventoried for a truck design, the corresponding frame height thereof, and the particular suspension desired, before all decisions concerning the dimensions of the suspension system and the truck frame height have been determined.  
           [0019]    Thus, an axle design that provides an adjustable, relative height between the center line of the associated wheels and the mounting surface of the axle with respect to a suspension system, would reduce inventory, reduce cost, and provide design flexibility. Design flexibility can be very important, since the more factors that may be determined at a later time, the more custom performance may be provided. That is, intransigent requirements driven by an inflexible design parameter associated with a particular component of a vehicle may drive costs upward for other features of the vehicle. Moreover, incompatibilities between components require specialized combinations that must be designed, documented, maintained, and so forth in order to support a production line thereof.  
         BRIEF SUMMARY AND OBJECTS OF THE INVENTION  
         [0020]    In view of the foregoing, it is a primary object of the present invention to provide adjustable height for auxiliary axles, and principal axles of a truck. It is contemplated that an apparatus and method in accordance with the invention may provide any principal axle (steering axle, drive axle) or auxiliary axle (leading axle, following axle, trailing axle) with a suitable range of adjustment for the relative height between the top mounting surface of the axle and the centerline of the associated wheels installed thereon.  
           [0021]    Consistent with the foregoing objects, and in accordance with the invention as embodied and broadly described herein, a method and apparatus are disclosed in one embodiment of the present invention as including an axle structure provided with a bracket for securing a mount thereto. Apertures in the bracket and mount may be positioned to match at a plurality of positions. Thus, fasteners may secure the mount to the bracket on each end of the axle at multiple relative positions therebetween.  
           [0022]    A standoff may be provided with the mount, for spacing a wheel assembly a distance away from the end bracket of the axle. Various sizes of tires and wheels may be accommodated by the adjustability between the mount and the bracket of the axle.  
           [0023]    The axle may mount to a frame of a vehicle by various mechanisms. A conventional suspension system may secure the axle to the vehicle frame, or a “pusher” assembly for selectively engaging the axle may be relied upon. In certain embodiments, a swing arm may mount a trailing axle to a vehicle.  
           [0024]    The axle may be formed as a beam of any suitable configuration, including an I-beam, a channel, a box beam, a right circular cylindrical tube, or the like, as a like. Various struts, gussets, fasteners, and the like may secure the brackets to the axle, and the mounts to their respective standoffs for supporting the axle on a vehicle, and the wheels with respect to the axle, respectively. In one embodiment, the mounting hardware for connecting an axle to a vehicle may be integral to the axle. In an alternative embodiment, the axle may be integrally constructed with the suspension system to further reduce weight. Accordingly, the adjustable standoffs for the wheel assemblies may be adjusted to fit the vehicle supported by the apparatus.  
           [0025]    Wheel assemblies may be connected to the mount associated with an axle by means of kingpins, axles, drive axles, fixed spindles, or the like. Thus, a wheel assembly may serve as a driver, a steering assembly, or an auxiliary assembly. Also, a wheel assembly may function as a caster on a kingpin connected to a mount and bracket associated with an axle.  
           [0026]    In certain embodiments, tie rods may connect wheels that caster or turn, and may connect to dampers (hydraulic or pneumatic buffers) for reducing oscillations.  
           [0027]    Universal joints may connect drive axles to axle stubs or spindles driving wheel assemblies. Accordingly, a differential may be provided within an axle in accordance with the invention, having drive axles contain therein for driving connected wheel assemblies. Thus, an axle assembly in accordance with the invention may serve as a principal steering axle of a vehicle, a drive axle of the vehicle, an auxiliary leading or following axle or as a trailing axle, having castered or noncastered wheels mounted thereto.  
           [0028]    The standoff assembly may be straight, angled, offset (vertically or horizontally), shimmed (vertically or horizontally), hollow, filled, or the like, in accordance with the desired functionality for the wheel assemblies connected to the axle. Thus, a standoff may position a drive wheel a distance away from a bracket of an axle, both horizontally and vertically, in order to accommodate vehicle size, axle size, suspension dimensions, and any requirement for mobility (e.g. U joints and drive-ins). 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]    The foregoing and other objects and features of the present invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are, therefore, not to be considered limiting of its scope, the invention will be described with additional specificity and detail through use of the accompanying drawings in which:  
         [0030]    [0030]FIG. 1 is a rear quarter perspective view of an axle assembly attached to a frame of a vehicle, in accordance with the invention;  
         [0031]    [0031]FIG. 2 is a rear quarter perspective view of the axle assembly of the apparatus of FIG. 1;  
         [0032]    [0032]FIG. 3 is rear quarter perspective view of the apparatus of FIGS.  1 - 2  having one wheel assembly and king pin removed for clarity;  
         [0033]    [0033]FIG. 4 is a top plan view of the axle assembly of FIGS.  1 - 3 ;  
         [0034]    [0034]FIG. 5 is a front elevation view of the apparatus of FIGS.  1 - 4 ;  
         [0035]    [0035]FIG. 6 is a side elevation view of a truck having six axles, any one of which may be an axle in accordance with the invention singly or in any combination;  
         [0036]    [0036]FIG. 7 is a rear quarter perspective view showing a portion of a standoff in phantom in order to demonstrate an optional drive linkage for driving a wheel assembly supported by an axle in accordance with the invention;  
         [0037]    [0037]FIG. 8 is a front elevation view of an alternative embodiment of a standoff in accordance with the invention; and  
         [0038]    [0038]FIG. 9 is a front elevation view of a horizontally shimmed apparatus in accordance with the invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0039]    It will be readily understood that the components of the present invention, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the system and method of the present invention, as represented in FIGS. 1 through 9, is not intended to limit the scope of the invention, as claimed, but is merely representative of the presently preferred embodiments of the invention.  
         [0040]    The presently preferred embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. FIGS.  1 - 9  illustrate certain presently preferred embodiments of apparatus and methods in accordance with the invention. Those of ordinary skill in the art will, of course, appreciate that various modifications to the detailed schematic diagrams may easily be made without departing from the essential characteristics of the invention, as described. Thus, the following description of the Figures is intended only by way of example, and simply illustrates certain presently preferred embodiments of the invention as claimed herein.  
         [0041]    Referring to FIGS.  1 - 9 , generally, and specifically to FIGS.  1 - 5 , an apparatus  10  may be configured as an axle assembly or an auxiliary axle assembly. That is, vehicles require wheels. Wheels require axles. Axles are mounted to vehicles by suspension systems. Principal axles include at least one drive axle and a steering axle. The steering axle supports rotating steering wheels and tires. The drive axle supports rotating drive wheels and tires. In accordance with certain embodiments of an apparatus and method in accordance with the invention, an apparatus  10  may provide an axle  12  provided with a bracket  14  attached to first and second ends  13   a ,  13   b , respectively.  
         [0042]    Each bracket  14  may be configured to be flat, curved, uniquely shaped, or the like, in order to receive a mount  16 . In one embodiment a bracket  14  may be penetrated by several apertures  15 . The apertures  15  may be aligned in one or more rows suitable for substitution one for another in receiving a fastener.  
         [0043]    Similarly, the mount  16  may be provided with several apertures  17  aligned in one or more rows. The apertures  17  may be matched to the apertures  15 , for positioning the mount  16  at one of several suitable attachable positions with respect to the bracket  14 .  
         [0044]    In practice, the apparatus  10  has corresponding operational directions that may be referred to for convenience, as a longitudinal direction  11   a , a transverse direction  11   b , and a lateral direction  11   c . The longitudinal direction  11   a  does not refer to the length of the axle  12 , but rather a longitudinal direction corresponding to forward and backward with respect to a vehicle to which the axle  12  and the apparatus  10  may be secured.  
         [0045]    In some selected embodiments, the apertures  15 ,  17  may be arranged in rows extending along a transverse direction  11   b . Accordingly, the apertures  15  may be matched with selected apertures  17  for securement of the mount  16  to the bracket  14  at a selected position. The bracket  14  and the mount  16  need not be of the same dimension in a transverse direction  11   b . For example, in order to provide a larger number of apertures  15 ,  17  that may be matched, while providing a greater bearing length of engagement between the bracket  14  and mount  16 , the transverse direction  11   b  of either the bracket  14 , or the mount  16 , may be longer than the other.  
         [0046]    A standoff  18  may extend in any direction  11   a ,  11   b ,  11   c  suitable for positioning a wheel assembly  20  with respect to the axle  12 . In certain embodiments, a wheel assembly  20  may be mounted to pivot from a location some substantial distance from a centerline  19  of the axle  12 . In certain embodiments, one may think of the longitudinal direction  11   a  as corresponding to the forward and backward, nominal horizontal, direction, the transverse direction  11   b  corresponding to the nominal vertical direction, and the lateral direction  11   c  corresponding to a side-to-side horizontal direction. Nevertheless, all naming conventions for the directions  11   a ,  11   b ,  11   c  are merely for convenience and reflect no absolute orientation in space being required necessarily.  
         [0047]    Thus, a standoff  18  may typically position a wheel assembly  20  above a centerline  19  of an axle  12 , in order to provide a maximum clearance  21  between the axle  12 , and the frame  30  of a vehicle.  
         [0048]    Likewise, the size of a tire  22  and wheel  24  rotating about the mount  16 , compared with a desired ground clearance  23  between a mounting position  25  of the axle  12 , and a surface on which the tire  22  of the wheel assembly  20  rolls.  
         [0049]    A framing member or beam  26  (e.g. cross beam  26 ) may support a mount  28  for the axle  12 . The beam  26  may be a part of the frame  30  of a vehicle. Nevertheless, the overall clearance  21 ,  23  may be accommodated by adjusting the mounts  16  in a transverse direction  11   b  with respect to the brackets  14 . The clearance  21  provides for a suspension system  29 , such as an air bag  29  or other load bearing mechanism  29 , that may be used to support the vehicle frame  30  above and against the axle  12 . In the case of the embodiment illustrated in FIG. 1, the axle  12  is a trailing axle  12 . Nevertheless, in other embodiments, the axle  12  may be mounted directly below the frame  30  of a vehicle, in order to provide either principal axle functions, or auxiliary axle functions.  
         [0050]    In a trailing axle configuration, brackets  32  may mount to structures that may or may not be part of the organic frame  30  of a vehicle. In the illustrated embodiment, the brackets  32  include an L-shape for fitting the vehicle frame  30  directly. The brackets  32 , pivotably mounting the axle  12  to the frame  30 , correspond to rear brackets  33  secured directly to the axle  12 . Pins  34 ,  35  support pivoting or limited rotation by the arms  36 ,  37  with respect to the frame  30 , as well as with respect to the axle  12 .  
         [0051]    In certain embodiments, the pins  34 ,  35  may be inserted through journals  38 ,  39  or bushings  38 ,  39  adding additional bearing surface area against the pins  34 ,  35 , above the structural requirements dictating the materials and thicknesses of the arms  36 ,  37 . Thus, although the structural requirement for the arms  36 ,  37  may require only a comparatively thin wall, the pressure stresses from bearing the load supporting the frame  30  by the axle  12 , may urge the benefit of journals  38 ,  39  on a designer.  
         [0052]    Thus, the brackets  32 ,  33  and, together with the pins  34 ,  35  and the journals  38 ,  39  form a pivot assembly  40 . In one embodiment, the arms  36 ,  37  may be included as part of the pivot assembly  40 . Thus, a pivot assembly  40  provides for a substantially constant orientation in a circumferential direction  13  of the axle  12 , while providing substantial freedom to move in a transverse direction  11   b.    
         [0053]    Meanwhile, the overall swing arm assembly  42  certainly includes in its structure the brackets  32 ,  33 , the pins  34 ,  35 , or their equivalents, the arms  36 ,  37 , and the journals  38 ,  39 . Pivot assemblies  40  resist any translation in a lateral direction  11   c  by the axle  12  with respect to the frame  30 , and permit only a certain, limited, arcuate motion, contributing to the movement of the axle  12  in a longitudinal direction  11   a  with respect to the frame  30 . Thus, the axle  12  is supported to move in substantially a single direction  11   b  in response to roughness of a road, and the absorption of shocks associated with displacement of the axle  12  with respect to a road surface, and a vehicle frame  30 .  
         [0054]    In certain embodiments, the axle  12  may be formed to have a beam  44 . The beam  44  may be configured as an I-beam, a channel beam (C-beam), and H-beam, a right circular, cylindrical, tubular beam, or a rectangular beam of some suitable cross-section. The beam  44  supports primarily a bending load due to support of the vehicle frame  30  by the axle  12 , through the suspension system  42 , a swing arm suspension system  42 , in the embodiment illustrated in FIG. 1.  
         [0055]    In certain embodiments a strut  46  or gusset  46  may secure a bracket  14  to the axle  12  in order to support offset. For example, in certain embodiments a road axle  12 , is desirable. Nevertheless, in many commercial vehicles, a comparatively large-diameter, off-road tire  22  is desirable. To reconcile these two issues, the axle  12  may be dropped with respect to a center line  45  of a tire  22  and a wheel  24 . Thus, a bracket  14  may extend a substantial distance in a transverse direction  11   b  above the axle  12 . Accordingly, a strut  46  of suitable structural materials and directions, may strengthen attachment of the bracket  14  to the axle  12 . Likewise, for suitably fitting a vehicle to a tire stance, an offset may be desirable in a transverse direction  11   b , lateral direction  11   c , or both. As illustrated and explained hereafter, the apparatus  10  is adaptable to such variations due to its modular nature.  
         [0056]    The bracket  14  may be secured to the mount  16  and vice versa, by fasteners  48 . The fasteners  48  may be removable or permanent. For example, permanent fasteners  48  may include rivets, welds, or other specialized fasteners. By contrast, removable fasteners  48 , or selectively removable fasteners  48  may include bolts, clamps, and the like. Typically, the threaded fasteners  48  such as the bolt  49  and the corresponding nut  47  may be readily and selectively secured and removed from the bracket  42  and mount  16 . A selective number of fasteners  48  may be required. Similarly, a certain number of apertures  15 ,  17  may be required to be engaged with one another, in order to provide sufficient bearing distance to support bending loads exerted by the wheel assembly  20  and standoff  18 , through the mount  16 , against the fasteners  48  connecting to the bracket  14 . Thus, to prevent bending of the bracket  14  or mount  16 , in service, a sufficient bearing distance may be specified, and only a limited number of fasteners  48  may be removed. Likewise, a limited number of apertures  15 ,  17  may be required to be engaged, or permitted to be unused.  
         [0057]    In certain embodiments, the wheel assemblies  20  secured to each end  13   a ,  13   b  of the axle  12  may be configured to function as casters with respect to the axle  12 . A tie rod  50  may connect the wheel assemblies  20  for cooperative tracking. In certain embodiments, to provide greater stability in dynamic environments, bolts  52  and brackets  54 , or the like, may secure a damper  60  to the tie rod  50 . A damper  60  may resist relative motion between an actuator  61  secured to the tie rod  50 , and a mounting bracket  62  of the damper  60  secured to the axle  12 . Thus a damper may resist motion of the tie rods  50  in a lateral direction  11   c , damping against chatter Damper types may include a dashpot, viscous drag system, hydraulic cylinder, brake, buffer, or the like. A damper  60  may be hydraulic, pneumatic, or a combination device. Damping may be comparatively strong, comparatively weak, or non-existent. Nevertheless, damping has been found effective in reducing chatter of castered wheel assemblies  20  in actual operation.  
         [0058]    The tie rod assembly  50  may be secured to the wheel assemblies  20  by knuckles  56  and arms  58 . The arm  58  may serve as a lever in order for the tie rods  50  to pivot each wheel assembly  20  about an axis extending in substantially a transverse direction  11   b . Actually, an axis of rotation or a pivot axis for a wheel assembly  20  will be dictated by requirements of caster, camber, and other alignment factors associated with the wheel assemblies  20 .  
         [0059]    Continuing to refer to FIGS.  1 - 9 , and more particularly to FIGS.  1 - 5  a beam  44  may constructed to have one or more webs extending in a direction substantially corresponding to a plane containing the transverse  11   b  and lateral directions  11   c . In general, a web  66  may extend substantially as a vertical plane. Again, directions are only by way of an example, and not an absolute orientation. A web  66  or multiple webs, may be configured as side plates  66  and, in any event, may extend away from one or more flanges  68 . In certain selected embodiments, two flanges may flank a web  66 . Thus, flanges  68  may be configured as top and bottom plates  68 .  
         [0060]    Note that the standoffs  18  may also be configured as beams  44  having one or more webs  66 , and one or more flanges  68 . In one embodiment, the standoff  18  may include a web  66  or multiple webs  66 , having a variation in cross-section along a lateral direction  11   c . For example, a web  66  of the standoff  18  may be cut away in order to provide operating clearance for the lever arm  58  associated with the tie rod assembly  50 .  
         [0061]    In one embodiment, the flange  68  may be formed so as to include a broken flange  69 . The broken flange  69 , is not actually broken, rather, the flange portion  69  extends in a plane or as a surface intersecting the basic flange  68 . Accordingly, the flanges  68 ,  69  accommodate the change in cross-section of the webs  66  of the standoff  18 . To the extent that a wheel assembly  20  should pivot with respect to the standoff  18  and axle  12 , a kingpin assembly  70  may support pivoting. In one embodiment, a kingpin  72  may penetrate a yoke  74  corresponding to a spindle assembly supporting the wheel assembly  20 . Although the spindle is not shown, a spindle serves as the member supporting bearings and rotation of a tire  22  and wheel  24  with respect to the kingpin  72  and the axle  12 . Accordingly, a yoke  74  may capture a bushing  76 . The bushing  76  may capture, together with the yoke  74 , the kingpin  72  extending therebetween. An aperture  77  may penetrate the bushing  76  for receiving the kingpin  72  therethrough.  
         [0062]    The wheel assembly  20  may be provided with a brake drum  78  for braking the wheel assembly  20  with respect to the axle  12 . A spindle plate  80  may extend into the break drum  78 , supporting the spindle about which the tire  22  and wheel  24  rotate. A wheel  24  may be secured to the brake drum  78  or a turntable associated therewith, typically a hub, by lugs  82 . Nuts  84  secured to the lugs  82  may secure the wheel  24  in position.  
         [0063]    In general the apparatus  10  may be configured to operate as a principal axle or an auxiliary axle. Accordingly, a suspension system may be selected from any type of suspension system suitable for mounting the axle  12  to a frame  30  of a vehicle. In one embodiment, the apparatus  10  may be a trailing axle  12 . Similarly, however, a pivotable mount directly to a frame  30  may also lower the axle  12  from a position proximate the frame  30  to a peak position comparatively proximate the ground. Plates  86 , or similar brackets  86 , may secure a swing arm assembly  42  to the frame  30 . An intermediate structure  26  devoted to the apparatus  10 , may or may not be appropriate. The frame  26  may actually be a portion, such as a cross-member  26 , of the organic vehicle frame  30 .  
         [0064]    Likewise, plates  88  or brackets  88  securing the axle  12  to a suspension system may be formed by any suitable means. In the embodiment illustrated, stiffeners  90  are secured to plates  88  in order to create a box-like effect, adding stiffness and strength.  
         [0065]    Referring to FIGS.  4 - 5 , while continuing to refer generally to FIGS.  1 - 9 , an axle  12  may be fabricated from conventional metal sections, or may be fabricated into the beam structure  44  of the axle  12 . In one embodiment, an anchor plate  96  may cross between the webs  66  of the beam  44 , or between the flanges  68  of the beam  44 , or between all four. The anchor plate  96  may be solid, or may be relieved near corners, along certain sections, and the like, as may be advisable to optimize stress management in the beam  44 . In the illustration of FIGS.  4 - 5 , the anchor plate  96  may be positioned to directly support the strut  46  connected to the bracket  14 . Although the brackets  14  and the mounts  16  are illustrated as flat plates  14 ,  16 , curvature may be appropriate in certain circumstances. Likewise, a V-shaped, or other cross-sectional surface may serve to stiffen, strengthen, lock, align, or the like, the mount  16  with respect to the bracket  14 .  
         [0066]    Just as the anchor plates  96  may stiffen the beam  44  and support the struts  46 , a stiffener  98  may strengthen the standoffs  18 . As a practical matter, a stiffener  98  may also triangulate between certain of the flanges  68 , and the mount  16  secured to the bracket  14 .  
         [0067]    In certain embodiments, the flanges  68  may extend between the bushing  76  and the mount  16 . Nevertheless, as illustrated in FIGS.  1 - 3 , the flanges  68  may be partial, according to the weight, stress, and access considerations.  
         [0068]    Referring to FIG. 6, a vehicle  100  may include a bed  30 , a cab  120  mounted thereon, and a bed  104  supported thereby. The vehicle  100  may include multiple axles  106 - 116 . For example, the vehicle  100  may be equipped with a leading auxiliary axle  106 . A following auxiliary axle  108  may be added alone, or in combination with the leading auxiliary axle  106 . In a combination with the auxiliary axles  106 ,  108  both  106 ,  108 , or alone, the auxiliary axle  110  may trail vehicle  100  on a swing arm  42  supported by suitable suspension methods. For example, springs, shackles, air bags, hydraulic systems, and the like may support the loads between an axle  12  and the frame  30 .  
         [0069]    In certain embodiments, an axle  12 , or the apparatus  10  may be installed as the steering axle  112 . In other embodiments, an axle assembly  10  in accordance with the invention may be installed as the forward drive axle  114 , the rear drive axle  116 , or both. Thus, relying on the adaptability of the transverse adjustment of the clearance  23  of the axle mounting surface  25  above an operating surface, the axles  106 - 116  may all be of a type contemplated within the scope of the invention, each adjusted at an appropriate position for the application for which it is designed and installed.  
         [0070]    Referring to FIG. 7, while continuing to refer generally to FIGS.  1 - 6 , an apparatus  10  having an axle  12  with the corresponding bracket  14  and mount  16  may include a standoff  18  extending either straight in a lateral direction  11   c , or extending in a lateral direction  11   c , while angling upwardly or downwardly along a transverse direction  11   b . A drive axle  120  may be encased in the axle  12 , and driven by a differential associated therewith. Accordingly, a hub  122  may connect a wheel assembly  20  to a drive axle  120 . In certain embodiments, an optional drive knuckle  123  may facilitate offsetting the hub  122  from the drive axle  120 . Accordingly, a hub  124  connecting to a wheel assembly  20  may be displaced from the mount  16  a suitable distance. Meanwhile, bearings  126  associated with the axle  12  may be scaled to support a differential connected to the axle  12 . Likewise, bearings  128  may support rotation of the hub  122  at the wheel end of the standoff  18 .  
         [0071]    In one embodiment, a first universal joint  130  may provide rotational power taken from the drive axle  120  and aligned therewith. A second universal joint  132  may deliver power to the hub  122 , accommodating the difference in alignments between the hub  122 , and a drive shaft  134  connected to the first universal joint  130 . A spindle  136 , or a stub axle  136  may rotate in the bearing  128 , supporting the hub  122 . A faceplate  138  or bulkhead  138  may be formed in any suitable shape to support a bearing  128  and axle  136  or spindle  136 . Accordingly, the wheel  24  may mount to the face plate  124 , secured by the lugs  82 . Accordingly, the wheel assembly  20  may rotate with the axle  136 , driven at the rotational velocity or angular velocity of the drive axle  120 , but offset at a different position, in all three dimensions of space, as well as at any suitable angle deemed appropriate for proper tracking of the wheel assembly  20 .  
         [0072]    The standoff  18  may also serve as a gear box, transfer case, or the like. For example, in addition to the drive knuckle assembly  123 , gear reductions and the like may be provided in the standoff  18 . Accordingly, the standoff  18  may be sealed to support an oil bath, or simply to prevent debris from interfering with the smooth operation of the drive knuckle assembly  123 .  
         [0073]    The drive knuckle assembly  123  is by no means required. For example, a drive axle  120  may simply be carried in a floating bearing  128  positioned by the bolts  48  securing the mount  16  to the bracket  14 . In another embodiment, where the wheel assembly  20  is not a drive wheel (e.g. see the drive axles  114 - 116 ), a spindle  136  may be fixed with respect to the standoff  18 . That is, the spindle  136  may be identical to a coasting wheel assembly  20 , such as is used in a conventional, non-powered steering axle  112 . Thus, a castering wheel assembly  20  may be secured as illustrated in FIGS.  1 - 3 , yet a leading auxiliary axle  106  and a following auxiliary axle  108  need not caster. In fact, castering may be problematic, depending on space, alignment, terrain, and other considerations.  
         [0074]    Referring to FIG. 8, a shim  124  may augment the interface between the axle  12  and the standoff  18 . The shim  124  may be thought of as an additional standoff  18  adapted to extend the effective “width” of the apparatus  10  in a lateral  11   c  direction. Wheel assemblies may be shimmed wider apart according to the desired configuration of an apparatus  10  to be installed on a vehicle. Moreover, in certain embodiments bolts  48  may be arranged in a manner (e.g. distributed diagonally or horizontally) to provide direct lateral  11   c  positioning of the standoff  18  with respect to the axle  12 , or shimmed standoff, as required.  
         [0075]    Referring to FIG. 9, an apparatus  10  may include a standoff  18  having lands  120  and grooves  122  adapted to interleave for supporting the standoff. Lands  120  and grooves  122  on the mount  16  mate with grooves  122  and lands  120 , respectively on the standoff  18 . Thus, the bolts  49  may hold the standoff  18  to the axle  12 , while the lands  120  and grooves  122  (e.g. toothed structures) support the actually operating loads of the apparatus  10 .  
         [0076]    Thus, in an apparatus and method in accordance with the invention, one may fabricate a lightweight, height-adjustable axle. Different embodiments of standoffs may be used. Different embodiments of axles  12  may be used. Different types of beams  44  may be configured. Different types of mounting mechanisms and the like for securing wheel assemblies to rotate with respect to the axle  12 , may be used in order to support steering, driving, trailing, and auxiliary leading or following.  
         [0077]    From the above discussion, it will be appreciated that the present invention provides a lightweight, height-adjustable axle for use as a steering axle, drive axle, auxiliary leading axle, auxiliary following axle, or auxiliary trailing axle for a truck. The apparatus may be mounted by any suitable, conventional suspension system in the art of principal axle mounting or auxiliary axle mounting for trucks and the like.  
         [0078]    The present invention may be embodied in other specific forms without departing from its essential characteristics. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.