Abstract:
A vehicular suspension system has a hanger to attach beneath a vehicle, a rocker pivoted at a first end to the hanger and attached proximate a second end to an axle, a shock absorber extending between the hanger and an intermediate position on the rocker, as well as likely a spring on the rocker&#39;s second end to push up against the overhead vehicle. The suspension system incorporates an axle saddle configured for more strongly welding to the axle, as well as a composite construction for the rocker to make a tube and thereby achieve a more strongly welded connection to the axle saddle. The suspension system further incorporates a rocker-to-hanger rocking axis alignment subsystem as well as a shock-absorber protection subsystem.

Description:
CROSS REFERENCE TO PROVISIONAL APPLICATION(S) 
   This application claims the benefit of U.S. Provisional Application No. 60/454,858, filed Mar. 14, 2003, which provisional application is incorporated herein in full by this reference. 

   BACKGROUND AND SUMMARY OF THE INVENTION 
   The invention relates vehicular suspension systems and, more particularly, to those employing longitudinally trailing rocker or control beams. An example typical use environment includes without limitation heavy-duty, over-the-road trailers having tandem dual, triple, or quadruple and so on axles rated at a unit axle capacity of 25,000 pounds (˜10,000 kilos) each. 
   It is an object of the invention to provide an axle saddle design that provides an enhanced, stronger welded connection to the wheel axle. 
   It is an alternate object of the invention to provide a design for the trailing rocker- or control-beams so that they also provide an enhanced, stronger welded connection to the axle saddle. 
   It is another object of the invention to provide a rebound limiter subsystem which protects a shock absorber for said vehicular suspension system from potentially damaging instances of over-extension all at the same time as being completely contained within the vehicular suspension system itself, without requiring connection or coupling to extraneous parts such as either the vehicle frame, which forms no part of the invention, or the axle-and-wheel package, which likewise forms no part of the invention. 
   It is an additional object of the invention to provide the trailing rocker- or control-beam with an alignment subsystem in order to afford installers and/or end users the opportunity to adjust the alignment of the trailing rocker- or control-beam&#39;s rocking axis relative the vehicle. 
   A number of additional features and objects will be apparent in connection with the following discussion of preferred embodiments and examples. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     There are shown in the drawings certain exemplary embodiments of the invention as presently preferred. It should be understood that the invention is not limited to the embodiments disclosed as examples, and is capable of variation within the scope of the appended claims. In the drawings, 
       FIG. 1  is an exploded perspective view of vehicular suspension system in accordance with the invention which, in this particular instance, is an example of what is more particularly characterized as having each rocker- or control-beam&#39;s leading, pivoted end configured as a transverse bushing sleeve (and bushing therefor) for pivotally pinning between a pair of spaced flanges of a corresponding rocker hanger, and wherein the rocker-or control-beam&#39;s trailing portions are characterized as “underslung,” that is, relative the connection to the wheel axle; 
       FIG. 2   a  is an enlarged exploded perspective view of the right half of  FIG. 1 , with various elements further exploded or fragmented and various other elements removed from the view for convenience in order to better show aspects related to one embodiment of a rebound limiter subsystem in accordance with the invention; 
       FIG. 2   b  is an exploded perspective view comparable to  FIG. 2   a  except showing an alternate embodiment of a rebound limiter sub-system in accordance with the invention and also except that various elements from  FIG. 2   a  are removed from this view for convenience sake; 
       FIG. 2   c  is side elevational perspective view fairly comparable to  FIG. 2   b  except showing the elements of  FIG. 2   c  assembled and not exploded, and including illustration of a representative shock absorber; 
       FIG. 3  is an exploded perspective view comparable to  FIG. 2   a , except showing an alternative embodiment of a vehicular suspension system in accordance with the invention, wherein in contrast to  FIGS. 1 and 2   a  which show underslung rocker- or control-beam(s), this view shows an overslung configuration for such rocker- or control-beam(s); 
       FIG. 4  is an exploded perspective view comparable to  FIG. 2   a , except showing a still different embodiment of a vehicular suspension system in accordance with the invention wherein, although like  FIGS. 1 and 2   a  this view shows an underslung rocker- or control-beam(s), unlike in  FIGS. 1 and 2   a  this view shows rocker- or control-beam&#39;s leading, pivoted end configured as a yoke with spaced arms for flanking the transverse bushing sleeve, which has been moved from the leading, pivoted end of the rocker- or control-beam and instead been incorporated in the rocker hanger; 
       FIG. 5  is an enlarged perspective view of an axle saddle in accordance with the invention and as shown previously in  FIGS. 2   a ,  3  (although inverted therein) and  4 ; 
       FIG. 6  is a perspective view showing portions of the axle saddle of  FIG. 5  in a welded up assembly condition with an axle (that forms no part of the invention); and 
       FIG. 7  is an enlarged exploded perspective view of portions of  FIG. 1 , with various elements illustrated in more particular detail and various other elements removed from the view for convenience sake in order to better show the rocking-axis alignment subsystem in accordance with the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  shows a first embodiment of a vehicular suspension system  10  in accordance with the invention. This suspension system  10  comprises a pair of frame hangers  20  for securing to the underside of the vehicle&#39;s frame (vehicle and/or frame therefor are not shown). Each hanger  20  carries a longitudinally trailing rocker- or control-beam  30 . This embodiment is characterized in part as having each rocker- or control-beam  30 &#39;s leading, pivoted end  32  configured as a transverse bushing sleeve  35 , as for receiving a bushing  18  therein. The hanger  20  has a pair of spaced depending flanges  22  with pin holes or slots  24  for accepting a pivot pin  28  that pivotally pins the rocker- or control-beam  30  to the hanger  20 , such that the pin  28 &#39;s axis defines the rocking axis for the beams  30 . This embodiment is characterized in other part as having the rocker- or control-beam  30 &#39;s trailing portions  38  designed as “underslung” as, that is, relative to being connected to the wheel axle A from below (in contrast to above). 
   Other aspects of the suspension system include a pair of shock absorbers  40 , one for each hanger-and-beam combination. Each shock absorber  40  has an upper end  42  pinned to the respective hanger  20  by fasteners  43  and lower ends  46  pinned to the corresponding rocker- or control-beam  30  by fasteners  47  at a position spaced away from the rocking axis (eg., pivot pin  28 &#39;s central axis) as shown. Also, there are a pair of air springs  50 , one for each beam  30 , that have lower ends  52  fastened to the beam tails  38  by fasteners  53  and upper ends  56  fastened to the underside of the vehicle frame (vehicle and/or frame therefor are not shown). 
   Other aspects of the invention include a beam-to-hanger rocking axis alignment or adjustment subsystem  90  for each hanger and as will be more particularly described below in connection with  FIG. 7 . Also, there are various other inventive aspects involved with the beam-to-axle connection as will be will be more particularly described below in connection with  FIGS. 3 through 6 . Additionally, there is an inventive rebound limiter subsystem  60  for each beam-and-hanger combination as more particularly described next in connection with  FIGS. 2   a  through  2   c.    
   Starting first in  FIG. 2   c , it shows that one aspect of the rebound limiter subsystem  60  involves protecting the corresponding shock absorber against potentially damaging instances of over-extension. In use, if the vehicle is traveling over rough road and the wheels bounce, the lower limit of the wheel&#39;s bounce will be jerked to a stop by the tightening chain (eg., indicated as reference numeral  62  in  FIG. 2   a  or  2   b ). That way, the shock absorber won&#39;t be overextended, which can damage/destroy it. 
   To turn back to  FIGS. 2   a  and  2   b , these views show another aspect of the rebound limiter subsystem  60 . And that is, namely, that all its operative components are wholly incorporated or integrated within the suspension system  10 . That way, the rebound limiter subsystem  60  is pre-packaged within the overall vehicular suspension system  10 . Accordingly, installers installing the vehicular suspension system  10  in accordance with the invention are served by its convenient “plug-and-play,” ready-to-go completeness once the hangers  20  and air-spring tops  56  are fastened. In other words, there is no necessity for an installer to make another attachment to the vehicle and/or its frame (vehicle and/or frame therefor are not shown) for the sake of the rebound limiter subsystem  60 . The chain  62 &#39;s length and its terminal connections  66  and  68  are “factory” set, so to speak. 
   This is all achieved as shown by  FIG. 2   a  with a chain  62  extending between opposite tag ends. The lower tag end has a clevis  64  attached to it. The upper tag end has the end link  63  turned crosswise in the immediately preceding link and welded fixed in the condition as shown. The beam  30  has an inboard lateral wall on which is formed (eg., welded thereto) a tab portion  66 , which has a hole through it for the clevis  64  to couple to. The inboard flange of the hanger  20  comparably has a tab portion  68  formed on it (eg., welded thereto). The tab portion  68  on the hanger has a T-shaped slot  69  formed in it for affording quick-connect and -disconnect of the chain  62 &#39;s crosswise end link  63 . The length of the chain  62  and the placement of the respective tab portions  68  and  66  on the hanger and beam  20  and  30  respectively are chosen for safely protecting given shock absorbers from potentially damaging over-extension wear and tear. 
     FIG. 2   b  is fairly comparable to  FIG. 2   a  except showing an alternate embodiment of a rebound limiter subsystem  60   1 , wherein the chain is provided with devises  64  at both ends. The hanger  20 &#39;s tab portion  68   1  is modified to substitute a simple round hole for the T-shaped slot. This  FIG. 2   b  version of the rebound limiter subsystem  60   1  in accordance with the invention provides more secure connection of the chain  62  to its anchorage at both ends. However, it also sacrifices the convenient quick-connect/-disconnect aspect of the  FIG. 2   a  version. 
   The rebound limiter aside,  FIG. 2   a  shows other aspects of the vehicular suspension system  10 . Namely, that the beam  30  is a composite of two channels  70  and  71  faced edge-to-edge, and ultimately welded together to form a rectangular or square tube. The advantage of this construction is that the beams  30  preferably slightly thin out along their extension. Accordingly, the beams  30  are ever so slightly tapered. It is not known if solid-piece tapered tubing is available in the measures and materials required for practicing the invention. Therefore, it is one solution to fabricate such tapered tubing to meet the measures and materials required by doing so with a composite construction as shown, involving butt-welding two channel pieces as shown. 
   With that in mind, further aspects of the invention relate to an inventive axle saddle  80  as indicated by reference numeral in  FIG. 2   a , or more particularly in concern of its design advantages for connecting to an axle (not shown in  FIG. 2   a ). In addition, still further aspects of the invention relate to the overall execution of the beam-to-saddle connection. 
   To turn briefly to  FIGS. 3 and 4 , they show an alternative versions of the vehicular suspension system  10   3  and  10   4  in accordance with the invention. 
     FIG. 3  can be contrasted to  FIGS. 1 and 2   a , which show underslung beam-to-axle positioning. That is,  FIG. 3  shows overslung beam-to-axle positioning. 
   The  FIG. 4  vehicular suspension system  10   4  returns back to incorporating underslung beam-to-axle positioning. However, what is different with  FIG. 4  is the construction of the leading, pivoted end  34  of the rocker- or control-beam  30   4 . That is, this leading pivoted end  34  is configured in the fashion of a yoke, having spaced arms, as for flanking the transverse bushing sleeve  25 . Indeed, the transverse bushing sleeve  25  is moved from being a component of the leading, pivoted end of the beam  30  in  FIG. 1  (see, eg.,  35 ) to instead being a component of the rocker hanger  20   4  in  FIG. 4 . 
     FIG. 5  shows a preferred embodiment for the axle saddle  80  in accordance with the invention, as shown in isolation. The axle saddle  80  is formed on substantially a cylindrical geometry, comprising a portion or longitudinal slice of a cylinder. Indeed, the axle saddle  80  hereof nearly defines semi-cylinder. 
   More particularly, the axle saddle  80  extends longitudinally between opposite, arcing, lateral edges  81 . In addition, the axle saddle  80  extends along the warp of the cylindrical plane of its main body between spaced leading and trailing longitudinal edges  82   1  and  82   2 . Associated with each of the longitudinal edges  82   1  and  82   2  are closely allied, elongated slot apertures  84   1  and  84   2 , respectively. Each elongated slot aperture  84   1  or  84   2  is oriented on a lengthwise axis of its own that is substantially parallel with the longitudinal axis of symmetry for the cylindrical geometry of the axle saddle  80 , including being substantially parallel to the corresponding longitudinal edge  82   1  or  82   2  with which it is most closely allied. 
   The trailing longitudinal edge  82   2  is recessed into the main material of the axle saddle  80  by opposite incurved curvatures  85   2  that straighten out in a longitudinal weld track  86   2  that comprises a majority of the overall longitudinal extent of the axle saddle  80  as a whole. To turn to the leading longitudinal edge  82   1 , it is formed with multi-part aspects. That is, in one part, the leading longitudinal edge  82   1  is formed with opposite wings  88 . These wings  88  provide a gain for the longitudinal extent of the leading longitudinal edge  82   1  (indicated as the measure “L” in the drawing) over the nominal longitudinal extent between the lateral edges  81  (indicated as the measure “l” in the drawing). In other part, the leading longitudinal edge  82   1  is comparably recessed in as the trailing longitudinal edge  82   2 . That is, the leading longitudinal edge  82   1  is recessed into the main material of the axle saddle  80  by opposite incurved curvatures  85   1  that straighten out in a longitudinal weld track  86   1  that comprises a majority of the overall longitudinal extent “L” of the leading longitudinal edge  82   1  as a whole. What is left at the opposite extremities are a pair of prong tips  89  as shown. 
   Length aside, it is a non-limiting design objective of the invention that each of the recessed-in longitudinal edge  82   1  or  82   2  of the axle saddle  80  closely approximates a half (½) symmetry of the elongated slotted apertures  84   1 / 84   2 . 
     FIG. 6  shows various ones of the inventive objective(s) behind this design of inwardly-recessed longitudinal weld tracks (eg.,  86   1  or  86   2  in  FIG. 5 ) in combination with closely allied elongated slot apertures (eg.,  84   1  or  84   2  in  FIG. 5 ). More particularly,  FIG. 6  shows a leading longitudinal edge and its allied elongated slot aperture welded up to a prior art axle (which forms no part of the invention). Both the leading longitudinal edge and its closely allied, elongated slot aperture are welded to the axle by a multi-pass welding operation, to lay down multiple layers, wherein preferably this comprises at least three passes. Briefly, for background, welds deposited in two or more layers are generally better than those deposited in a single layer because the second and subsequent layers partly anneal the preceding layers, thereby reducing glass-like brittleness, and hence a joint of improve structure will result. 
     FIG. 6  shows that the elongated slot aperture is nearly smoothly filled with a hardened weld pool. More significantly, the elongated slot aperture affords the welder an endless track to run weld circuits around without having to leave behind any weld-seam ends or terminuses. Consequently, this avoids weld undercutting problems at any ends, which problems are something like an initiation site for a crack to form and thereafter unzip the weld seam. More importantly, the elongated slot aperture affords the welder a longitudinal pass along both sides of itself. To refer back to  FIG. 5 , the elongated slot apertures  84   1  and  84   2  are both about the same size, each having a longitudinal extent indicated in the drawing as the measure “λ.” Since any one of the elongated slot apertures  84   1  or  84   2  has two such elongated sides, then each side acts as a longitudinal weld track spaced away from each other. 
   Returning back to  FIG. 6 , it shows that the leading half of the axle saddle (eg.,  80 ) is secured to the axle (eg., A) by three longitudinal weld tracks, which together are substantially greater than the mere nominal width of the axle saddle (eg.,  80 ). The foregoing statement can be expressed in the previously established math symbols as follows:
 
“L”+(2×“λ”)&gt;&gt;“l”  (1)
 
   To give example values to the foregoing measures, assume a preferred axle A of the prior art measures five inches O.D. (12.7 cm Ø). Preferably then the inventive axle saddle  80  would have a nominal longitudinal extent “l” measuring about six inches (˜15¼ cm). More preferably still would be if the longitudinal span “L” between the prong tips  89  of the wings  88  measures about eight inches (˜20⅓ cm). It would be additionally preferred if the longitudinal extent “λ” of the leading, elongated slot aperture  84   1  measures about four to four-and-one-half inches (˜10⅛ to ˜11⅜ cm). Therefore, the advantages over a mere extent of “λ” in contrast to the span “L” between the prong tips  89  in combination with the leading elongated slot aperture  84   1 &#39;s two sides extending about “λ” each provides a substantial increase. For example,
 
8″+(2×4½″)&gt;&gt;6″  (2)
 
That is, the right-side of equation (2)&#39;s six inches (˜15¼ cm) is much less than the left-side&#39;s seventeen inches (˜43⅛ cm). In sum, the combination of the wings  88  and leading elongated slot aperture  84   1  affords a designer the opportunity to distribute the incremental stress-carrying capacity of the leading half of the axle saddle  80 &#39;s saddle-to-axle loads over about seventeen inches (˜43⅛ cm) of weld seam in contrast to a simple six inches (˜151¼ cm) without.
 
     FIG. 6  shows another of the various advantages of the inventive configuration for the design of the axle saddle. Namely, the recessed-in weld tracks (eg.,  86   1  or  86   2 ) on either the leading or trailing longitudinal edges allows the following distinct advantage. That is, the weld seams therein can be terminated in smoothly diminishing ends or terminuses. In other words, at least the terminuses are not bluntly ended bulbs which afford under-cutting or longitudinally in-creeping crack propagation from initiation sites in such bluntly ended bulbs. The objective is to flare out the weld seams in directions (eg., the radial direction) and diminish them in smoothly receding tapers so as to minimize crack initiation and propagation as plagues bluntly-ended weld seams, by a phenomenon referred to in the industry as weld undercutting. 
     FIG. 2   a , representative of the other versions  10   3  and  10   4  of the inventive suspension system as well, shows further aspects of the beam-to-saddle connection. 
   Again, the beam  30  is preferably is a construction of laterally opposed channel members  70  and  71 . The weld seams which join the channel members are oriented to extend over the top and bottom of the welded up end-assembly  30  (weld seams are not shown in  FIG. 2   a ). The beam  30  is formed with a cut-out  72  sized and arranged generally for a close-fitting joining-up with the axle saddle  80 &#39;s outside surface. That is, the cut-out  72  is defined by longitudinal weld tracks  73  and  74  along the top flanges of the web members  70  and  71  respectively. The cut-out is further defined by arc-section lateral weld tacks  76  and  77 . Given all the foregoing lines of weld tracks, the rocker- or control-beam  30  is thereby substantially secured or fixed to the axle saddle  80 . 
   To now refer to  FIG. 7 , it shows a preferred embodiment of a rocking-axis alignment subsystem  90  in accordance with the invention. As described previously, the rocker- or control-beam  30 &#39;s leading, pivoted end  32  or  34  is configured for rocking coupling with its associated rocker hanger. 
   In this  FIG. 7 , the beam  30 &#39;s leading, pivoted end  32  comprises a transverse bushing sleeve  35 , in which is inserted a bushing  18  for it. The bushing sleeve  35  and bushing  18  are flanked by opposite wear washers  91  as well as opposite collar inserts  92  therefor. The axle A is partly broken away in the drawing, as are other parts. The rocker hanger  20  comprises a pair of spaced flanges  22 , each formed with a matching alignment slot  24  for accepting the through insertion of the pivot bolt  28 . Importantly, the pivot bolt  28 &#39;s axis determines the rocking axis for the rocker- or control-beam  30  relative to the rocker hanger  20 . The pivot bolt  28 &#39;s actual position within the alignment slots  24  is adjustable by virtue of the rocking axis alignment subsystem  90 , as to be more particularly described next. 
   To review  FIG. 4  very briefly, the rocker- or control-beam&#39;s leading, pivoted end is configured as a yoke  34 , with spaced arms, which are arranged and spaced for flanking and clasping the transverse bushing sleeve  25  that in this instance is attached to the hanger. Regardless, the rocking-axis alignment subsystem  90  in accordance with the invention is readily adaptable to work with the  FIG. 4  version  10   4  of the invention as well. 
   In  FIG. 7 , the rocking-axis alignment subsystem  90  preferably comprises a gear rack  94  fixed to one, the other, or both of the rocker hanger  20 &#39;s flanges  22 . This or these one or two gear racks  94  are preferably spaced radially away from the respective slotted aperture  24  on the same flange  22 , wherein “radially” spaced away is understood as referenced in the plane of the rocker hanger  20 &#39;s flanges  22 . 
   The rocking-axis alignment subsystem  90  further comprises an alignment lever  95  having an aperture  96  for receiving and driving the pivot bolt  28  through the range of available positions between the opposite extremes therefor relative the hanger  20 . The alignment lever  95  preferably has an arc section formed with gear teeth. These gear teeth are sized and configured for meshing with the gear rack  94  as shown in part. This alignment lever  95  preferably further includes a crank attachment structure  97  adapted for accepting a releasably coupled drive crank (not shown) as would allow a worker to input a cranking force to the alignment lever  95  in order to move the pivot bolt  28  to any of various alignment positions available to it in the alignment slot  24 .  FIG. 7  shows an example crank attachment structure  97  to comprise a hexagonal nut welded to a tab on the alignment lever  95 . 
   In use, an installer or worker inserts the pivot bolt  28  through all of the following:—namely, the alignment lever(s)  95 , the alignment slots  24  in the rocker hanger  20 &#39;s flanges  22 , the rocking- or control-beam  30 &#39;s drive hole&#39;s therefor, and the bushing  18  (as well as all or any other auxiliary components such as collars  92  and washers  91 ). After threading the pivot bolt  28  through the applicable aforementioned structure, such a worker or installer can crank the pivot bolt  28  to any alignment between the range of available position between the extremes afforded by the alignment slot(s)  24 , and thereafter tighten and fix the position of the pivot bolt relative the rocker hanger  28  by virtue of tightening the nut and jam nut combination  98  therefor. 
   The invention having been disclosed in connection with the foregoing variations and examples, additional variations will now be apparent to persons skilled in the art. The invention is not intended to be limited to the variations specifically mentioned, and accordingly reference should be made to the appended claims rather than the foregoing discussion of preferred examples, to assess the scope of the invention in which exclusive rights are claimed.