Abstract:
The invention provides a single member insert positionable between a front axle and each front leaf spring as a spacer. The member allows attachment of one end of a shock absorber for bracing against the axle. The member also serves as a caster wedge for maintaining proper steering response.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention: 
     The present invention relates vehicle suspension systems and more particularly to the assembly of the suspension for a steering axle installed at the front end of a vehicle such as a truck. 
     2. Description of the Prior Art: 
     A common type of front end suspension for a truck steering axle relies on leaf springs positioned adjacent to and above opposed ends of the steering axle to locally support the weight of the truck from the axle. The leaf springs are elongated, flexible bars mounted perpendicular to the axle and parallel to the to major frame side rails of the vehicle chassis. Each leaf spring is rigidly attached at approximately its center point to the steering axle. Opposite ends of each leaf spring are coupled to a frame side rail fore and aft of the axle, helping to align and locate the axle. Shock absorbers are attached between the frame side rails and each end of the axle to dampen motion. 
     The assembly of front end suspensions requires the inclusion of components which: allow for the attachment of the shock absorber between the vehicle chassis and the axle; establish the proper spacing between the leaf spring and the axle to place the vehicle at its proper height; and, insure the proper alignment of the suspension and steering components. A factor complicating front end suspension assembly is that leaf springs of different sizes are used depending upon the anticipated use of the truck. Typically, leaf springs having a width of 3″ (7.6 cm) are used for medium duty applications while leaf springs having a width of 4″ (10.2 cm) are used for heavy duty applications. The differences in spring widths have prevented the use of a single element spacer in front end suspensions which meets the need to position the vehicle, insure proper alignment of the components for steering and provide a connection point for a shock absorber. While single piece devices exist which provide for one spring width, none is known to the inventors which works with springs of different widths. 
     A single piece device providing spacing, alignment and shock absorber installation to both common leaf spring widths would simplify manufacture. Such an element should also be easy to install correctly during vehicle assembly. What is needed is a unitary spacer, connector and alignment element which simplifies manufacture and reduces the number of parts to be kept in inventory. 
     SUMMARY OF THE INVENTION 
     The invention provides a vehicle suspension subassembly for a steering axle having a reduced number of parts and exhibiting interchangeability among leaf springs of differing sizes. The leaf springs at each end of a steering axle have mounting pads. The steering axle has horizontally disposed mounting pads adjacent to each end for cooperation with the leaf spring mounting pads. A spacing element disposed between mounting pad and the leaf spring has top and bottom major surfaces for mating with the leaf spring mounting pad and the steering axle mounting pad. The outside vertical sides of the spacing element are shaped to fit snugly against U-bolts of differing sizes used with leaf springs of different widths. The top and bottom major surfaces of the spacing element are canted with respect to one another to set steering axle caster. A shock absorber mount extends from the spacing element. 
     Additional effects, features and advantages will be apparent in the written description that follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is an exploded view of a prior art suspension subassembly; 
     FIGS. 2A and 2B are perspective views of a prior art integrated spacing element, caster wedge and shock absorber mount; 
     FIGS. 3A-B are perspective views of an integrated front lower shock mount, axle spacer and caster wedge in accordance with a preferred embodiment of the invention; 
     FIG. 4 is an exploded view of a suspension assembly incorporating a spacing element in accordance with one embodiment of the invention; 
     FIG. 5 is a partial cross-sectional view of the integrated front lower shock mount, axle spacer and caster wedge cooperating with two U-bolts; 
     FIG. 6 is a perspective view of a suspension subassembly incorporating a spacing element in accordance with the preferred embodiment; and 
     FIG. 7 is a perspective view of an alternative suspension subassembly incorporating the spacing element in accordance with the preferred embodiment. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates in an exploded view the components in a typical prior art front end suspension mounting subassembly  10  for a truck. Subassembly  10  has the function of rigidly attaching a leaf spring  16  to a steering axle  12 . As is well known to those skilled in the art, leaf spring  16 , which is coupled at its opposing ends to a vehicle frame (not shown), functions to locate and orient steering axle  12 . Subassembly  10  includes separate components directed to each of three subsidiary functions: (1) providing a link point for one end of a shock absorber  24 ; (2) adjusting steering axle caster; and (3) spacing leaf spring  16  from steering axle  12  to establish the correct unloaded ride height of the vehicle. Each subsidiary function is met by inclusion of a component within the subassembly  10 . Caster angle is set by a caster wedge  20  for positioning directly on top of an axle pad  14 . A shock absorber mount  26  extends from a support plate  22  positioned between the caster wedge  20  and a spacing element  28 . Spacing is provided by a spacing element  28  which mates with a lower alignment plate  34  on the bottom surface of leaf spring  16 . 
     As assembled, caster wedge  20 , support plate  22  and spacing element  28  are stacked in alignment with one another between axle pad  14  and lower alignment plate  34 . Alignment pins  35  and  18 , extending from alignment plate  34  and axle pad  14 , respectively, align wedge  20  and spacing element  28  on the alignment plate and the axle pad, respectively. Pin  18  rests in a alignment hole  42  in pad  14 . A U-bolt seat  30  rides on a upper alignment plate  32  formed on the upper surface of leaf spring  16 . U-bolt seat  30  is aligned on an alignment pin  33  and includes two U-bolt receiving grooves  31  on its upper surface. A pair of U-bolts  36  can rest in grooves  31 , straddling the leaf spring  16  with each leg extending through one of receiving bores  40  through axle pad  14 . The caster wedge  20 , support plate  22  and spacing element  28  are rotationally aligned by the legs of U-bolts  36  passing adjacent to and abutting the outside edges of the subassembly elements. Four nuts  38  are provided to secure the legs of U-bolts  36  against the bottom surface of pad  14 . 
     FIGS. 2A and B illustrate a prior art spacing element  44  used in some applications as a substitute for a separate caster wedge  20 , support plate  22  and spacing element  28 . Essential features of element  44  are an alignment pin receiving hole  46  on the upper face of the element, an alignment pin  50  projecting from the lower face, and a shock absorber mount  49  extending from one end of the element. An operative hole  48 , through which a bolt for mounting shock absorber  24  on, passes through the mount  49 . The top and bottom surfaces of spacing element  44  may be canted with respect to one another to set steering axle caster. Element  44 , as with the plurality of elements discussed with reference to FIG. 1, is rotationally aligned by U-bolt legs abutting the major outer sides  51  and  53 . Because the major outer sides  51  and  53  are flat, the width of spacing element  44  must match the spacing between the legs of the U-bolts with which it is to be used. U-bolts  36  are, in turn, sized for a particular width of leaf spring and, as a result, spacing elements constructed in accordance with the design of element  44  must be sized for each width of leaf spring with which they are to be used. The hole  48  through mount  49  has a length equal to the width of the element  44 , necessitating the use bolts long enough to extend through the hole and allow the mounting of shock absorber  24 . This issue complicates casting of the piece. 
     FIGS. 3A-C illustrate an integrated, one piece front lower shock mount, axle spacer and caster wedge unit  52  in accordance with a preferred embodiment of the invention. Among the advantages of integrated unit  52  over the prior art is that one size of unit can be used with U-bolts of different widths and retain ease of achieving rotational alignment during vehicle assembly. Integrated unit  52  has an indentation  54  in its upper surface  65  for receiving an alignment pin  35  extending downwardly from a leaf spring  16 . The bottom major surface  63  includes an alignment pin  72  which extends downwardly for insertion into receiving hole  42  on axle pad  14 . 
     Integrated unit  52  has outer, profiled edges or sides  56  and  58  on the sides of the unit intended to be placed in contact with the bolt legs. Profiled sides  56  and  58  terminate at each end in projecting ears  60 A-D. Projecting ears  60 A-B border profiled side  56  and projecting ears  60 C-D border profiled side  58 . Each profiled edge, substantially adjacent a projecting ear, has a notch for receiving a leg of a U-bolt. Notch  64  is adjacent ear  60 A on profiled side  56 . Notch  62  is adjacent ear  60 B on profiled side  56 . Notch  66  is adjacent ear  60 C on profiled side  58 . Notch  68  is adjacent ear  60 D on profiled side  58 . Extending from ear  60 A is a shock absorber mount  74 , which defines a hole  70  for receiving a bolt. Lower and upper major surfaces  63  and  65  are canted with respect to one another to set steering axle caster. 
     FIG. 4 is an exploded view of a suspension mounting subassembly  10 B incorporating an integrated unit  52 . Integrated unit  52  is oriented to bring its upper surface  65  into contact with lower alignment plate  34  which faces it from a lower surface of leaf spring  16 . Lower surface  63  (shown in FIGS. 3A-C) is oriented to come into contact with axle pad  14  and aligned to introduce alignment pin  72  to alignment hole  42 . Profiled sides  56  and  58  are oriented parallel to the direction of elongation of leaf spring  16 . A bolt  76  is provided to be introduced through mount  74  to support shock absorber  24 . Assembly requires that the U-bolts  36  be positioned straddling leaf spring  16 , inverted with the bottom of the U-shaped portion of the bolts resting in grooves  31 . The legs of U-bolts  36  abut the surface of profiled sides  56  and  58  to rotationally align integrated unit  52  as they are fitted through holes  40  in axle pad  14 . 
     FIG. 5 is a cross-sectional view illustrating the positional fit between integrated unit  52  and two sizes of U-bolts  36 A and  36 B along one profiled edge  56 . Profiled edge  56  is symmetric with profiled edge  58 , and accordingly, the fit of the U-bolts to the profiled edges is also symmetric from side to side. U-bolts  36 A and  36 B are sized to straddle leaf springs of two different widths, here 3″ and 4″ respectively. The legs of U-bolt  36 A, which are sized to straddle a 3″ width leaf spring fit deep in the recesses of notches  62  and  64 . The legs of U-bolt  36 B fit against the sloped side walls of notches  62  and  64  formed by ears  60 B and  60 A, outward from the point of contact for the legs of U-bolt  36 A. 
     FIG. 6 is a perspective view of a suspension subassembly  10 C providing attachment of steering axle  14  to a 3″ leaf spring  86 . The deep positioning of the legs for U-bolts  36 A in notches  62  and  64  may be readily seen. Integrated unit  52  is oriented squarely on axle pad  14  assuring the caster angle for the steering axle  14  is correctly set. Similarly, FIG. 7 illustrates a subassembly  10 D for a leaf spring  96  which is 4″ in width. The legs of U-bolts  36 B ride much more shallowly in notches  62  and  64  than in subassembly  10 B. The direction to the front of the truck on which the subassemblies are used is indicated in both figures by an appropriately labeled arrow. 
     The integrated caster wedge, front lower shock mount and spacer of the present invention provides replacement for 3 separate pieces in most manufacturing applications. Where prior art integrated units were used, the present invention provides a single size which fits differing widths of leaf springs. 
     While the invention is shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.