Abstract:
A trailing beam suspension comprises a hanger bracket adapted to be mounted to a vehicle frame, wherein the hanger bracket includes a mounting aperture, and a trailing beam pivotally mounted to the hanger bracket by a pivot pin extending through the mounting aperture of the hanger bracket. The trailing beam suspension also comprises an adjustable mechanism operably coupled to the hanger bracket including a selector member in operable engagement with the pivot pin and having a plurality of first coupler portions, and at least one second coupler portion that is selectively engageable with at least one of the first coupler portions, wherein adjusting the selector member such that alternative first coupler portions engage the at least one second coupler portion adjust the position of the trailing beam with respect to a vehicle frame rail in a fore-or-aft direction.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/580,548, filed Jun. 17, 2004, entitled TRAILING BEAM SUSPENSION WITH ALIGNMENT ADJUSTMENT ASSEMBLY, which is hereby incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a vehicle suspension, and in particular to a trailing beam suspension for a wheeled vehicle in which the suspension includes a mechanism for four-and-aft adjustment of the alignment of an associated axle and wheels with respect to a longitudinal axis of the associated vehicle, and specifically the forward pivot point of the associated trailing beam assembly.  
         [0003]     Proper wheel alignment in road vehicles is important to prevent undue tire wear and to ensure proper vehicle handling and stability. Common causes of improper wheel alignment include improper initial suspension system installation, accidental damage, and impact or shock loads imposed on suspension components by potholes or other irregularities in the road surface.  
         [0004]     Wheel alignment adjustment mechanisms permit adjustment of the alignment of vehicle axles and wheel with respect to the vehicle frame. Adjustment mechanisms are generally one of two types: those that are adjustable as the suspension is installed on the vehicle and then permanently fixed in the adjusted position by welding and the like; and, those that are adjustable any time during and after installation and are held in the adjustment position mechanically, as described below.  
         [0005]     Strader et al., U.S. Pat. No. 3,960,388, is exemplary of the first category of alignment devices. The Strader &#39;388 patent discloses a trailing beam suspension that incorporates a mounting plate for the trailing beam having a pair of bosses that engage slots in the hanger bracket. The trailing beam is attached to the hanger bracket by a bolted connection in which the bolt passes through the mounting plate and is secured with a nut. The bolt head engages the mounting plate so that rotating the bolt pivots the mounting plate out of one of the bosses. Pivoting of the mounting plate moves the bolts fore or aft, which moves the trailing beam fore or aft to align the axle. When the axles and wheels have been properly aligned, the plate is welded to the hanger bracket. Further adjustment is possible only after removing the weld.  
         [0006]     U.S. Pat. No. Re. 30,308 to Masser discloses a trailing beam suspension system incorporating a mounting plate for the trailing beam having a single boss that engages a slot in the hanger bracket. The pivot bolt for the trailing beam passes through the mounting plate and slot. The trailing beam is moved fore or aft until proper alignment of the axle and wheels is achieved. The mounting plate is then welded to the hanger bracket. Further adjustment is possible only after removing the weld.  
         [0007]     Richardson, U.S. Pat. No. 4,991,872, discloses a trailing beam suspension for a low-bed trailer. The forward trailing beam of a pair of trailer beams is mounted to the intermediate, inclined portion of the main structure beam of the trailer through a bushing assembly. The bushing assembly is coupled to the web of the beam by a bolted connection. The web is provided with slotted mounting holes that enable adjustment of the alignment of the trailing beam and the attached axle. The trailing beam is moved fore or aft until the axle and wheels are properly aligned. After adjustment, the bushing assembly is welded to the beam. Further adjustment requires removal of the weld and loosening of four bolts connecting the bushing assembly to the trailer beam.  
         [0008]     An example of the second category of alignment devices is disclosed in U.S. Pat. No. 5,201,898 to Pierce. The Pierce &#39;898 patent discloses a trailing beam suspension incorporating a pair of complementary discs that engage each other with a channel arrangement with the trailing beam mounting boat passing therethrough. One of the discs is welded to the hanger bracket and incorporates an asymmetrical hole. The second disc contains an off-center hole that is rotatable relative to the first. The rotation of the second disc relative to the first is translated into lateral movement of the trailing beam mounting boat. It is necessary to restrain the second disc against further rotation while the connection is tightened to prevent movement of the trailing beam from its aligned position.  
         [0009]     In light of the aforementioned alignment adjustment mechanisms, a vehicle suspension alignment adjustment assembly is desired that allows alignment subsequent to the coupling of the vehicle suspension assembly with the associated vehicle, provides an ease of use with respect to that adjustment, and allows for adjustment in primarily a fore-and-aft direction without requiring the associated suspension components to be swung through an arc during adjustment, thereby maintaining the spatial relationship between the components of interest during adjustment and alignment of the suspension assembly.  
       SUMMARY OF THE INVENTION  
       [0010]     One aspect of the present invention is to provide a trailing beam suspension for a vehicle that comprises a hanger bracket adapted to be mounted to a vehicle frame, wherein the hanger bracket includes a mounting aperture, and a trailing beam pivotally mounted to the hanger bracket by a pivot pin extending through the mounting aperture of the hanger bracket. The trailing beam suspension also comprises an adjustment mechanism operably coupled to the hanger bracket including a selector member in operable engagement with the pivot pin and having a plurality of first coupler portions, and at least one second coupler portion that is selectively engageable with at least one of the first coupler portions, wherein adjusting the selector member such that alternative first coupler portions engage the at least one second coupler portion adjusts the position of the trailing beam with respect to a vehicle frame rail in a fore or aft direction.  
         [0011]     Another aspect of the present invention is to provide a trailing beam suspension for a vehicle that comprises a hanger bracket adapted to be mounted to a vehicle frame rail, wherein the hanger bracket includes a mounting aperture, and a trailing beam pivotally mounted to the hanger bracket by a pivot pin extending through the mounting aperture of the hanger bracket. The trailing arm suspension also comprises an adjustment mechanism operably coupled to the hanger bracket that includes a selector member having an aperture that receives the pivot pin and having a plurality of notches spaced about a periphery of the selector member, wherein each notch of the plurality of notches defines a distance between the notch and a centroidal axis of the aperture of the selector member, and wherein the distance defined by each notch is different from the distance defined by at least one other notch. The adjustment mechanism also includes at least one tab member that is selectively engageable with at least one of the notches of the selector member, wherein adjusting the selector member such that alternative notches engage the at least one tab member adjusts the position of the trailing beam with respect to the vehicle frame rail in a fore or aft direction.  
         [0012]     Yet another aspect of the present invention is to provide a trailing beam suspension for a vehicle that includes a hanger bracket adapted to be mounted to a vehicle frame rail, wherein the hanger bracket includes a mounting aperture, and a trailing beam pivotally mounted to the hanger bracket by a pivot pin extending through the mounting aperture of the hanger bracket. The trailing beam suspension also includes an adjustment mechanism operably coupled to the hanger bracket that includes a selector member having an aperture that receives the pivot pin and having a plurality of notches spaced about the periphery of the selector member, wherein a distance between each notch and a centroidal axis of the aperture of the selector member is defined by a cam wall extending about the aperture of the selector member, and wherein a radius of the cam wall changes about the circumference of the selector member. The adjustment mechanism also includes at least one tab member that is selectively engageable with at least one of the notches of the selector member, wherein adjusting the selector member such that alternative notches engage the at least one tab member adjusts the position of the trailing beam with respect to the vehicle frame rail in a fore or aft direction.  
         [0013]     The present inventive alignment adjustment assembly provides an uncomplicated design, can be easily and quickly assembled and adjusted subsequent to assembly with an associated vehicle frame, is efficient in use, capable of a long operating life, and is particularly well adapted for the proposed use. Moreover, the adjustment assembly the associated vehicle, provides an ease of use with respect to that adjustment, and allows for adjustment in primarily a fore-and-aft direction without requiring the associated suspension components to be swung through an arc during adjustment, thereby maintaining the spatial relationship between the components of interest during adjustment and alignment of the suspension assembly.  
         [0014]     These and other advantages of the invention will be further understood and appreciated by those skilled in the art by reference to the following written specification, claims and appended drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a perspective view of a vehicle frame and a vehicle suspension assembly;  
         [0016]      FIG. 2  is a side view of the vehicle frame and the vehicle suspension assembly;  
         [0017]      FIG. 3  is a perspective view of a trailing beam supported from a hanger bracket via a prior art welded-type couple;  
         [0018]      FIG. 4  is a side view of the trailing beam by the hanger bracket via the welded couple;  
         [0019]      FIG. 5  is a perspective view of a trailing beam supported from a hanger bracket via a prior art eccentric-type couple;  
         [0020]      FIG. 6  is a side view of the trailing beam supported by the hanger bracket via the eccentric couple;  
         [0021]      FIG. 7  is a perspective view of a trailing beam supported from a hanger bracket via a first embodiment of the alignment adjustment assembly embodying the present invention;  
         [0022]      FIG. 8  is a side view of the trailing beam supported from the hanger bracket by the first embodiment of the alignment adjustment assembly;  
         [0023]      FIG. 9  is a cross-sectional view of the first embodiment of the alignment adjustment assembly;  
         [0024]      FIG. 10  is an enlarged perspective view of a selector member of the first embodiment of the alignment adjustment assembly;  
         [0025]      FIG. 11  is a trailing beam supported from a hanger bracket by a second embodiment of the alignment adjustment assembly;  
         [0026]      FIG. 12  is a side view of the trailing beam supported from the hanger bracket via the second embodiment of the alignment adjustment assembly; and  
         [0027]      FIG. 13  is an enlarged perspective view of a selector member of the second embodiment of the alignment adjustment assembly. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]     For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in  FIGS. 1 and 2 . However, it is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.  
         [0029]     The reference numeral  10  ( FIGS. 1 and 2 ) generally designates a trailing beam suspension system embodying the present invention, and supporting a vehicle frame  12  therefrom. In the illustrated example, the suspension system  10  generally comprises a trailing beam  14 , a hanger bracket  16 , and an air spring  18 . The hanger bracket  16  is attached in a conventional manner to a vehicle frame rail  20  of the vehicle frame  12 . A first end  22  of the trailing beam  14  is pivotally mounted to the hanger bracket  16  via a pivot bolt  24  and a conventional bushed connector. A second end  26  of the trailing beam  14  is attached in a conventional manner to the air spring  18  so that the air spring  18  is disposed in load transmitting relation between the trailing beam  14  and the frame rail  20 . An axle  28  supports a wheel  30  and is coupled to the trailing beam  14  by an axle bracket  32 .  
         [0030]     As previously described, one prior art method, as best illustrated in  FIGS. 3 and 4 , includes supporting the trailing beam  14  from the hanger bracket  16  via a welded-type assembly  34 . Specifically, the hanger bracket  16  includes an elongated adjustment slot  36  that slidably receives the pivot bolt  24  therein. The pivot bolt also extends through a pair of spacer members  38  and a washer  40 , wherein the spacer members  38  are opposed across the hanger bracket  16  from one another. The pivot bolt  24  is held in initial assembly via an associated nut  42 . Subsequent to connection of the trailing beam  14  with the hanger bracket  16 , the adjustment of the axis  44  of the pivot bolt  24 , and thus the axis  46  of the axle  28 , is adjusted with respect to a longitudinal axis of the vehicle frame  12 , by adjusting the location of the pivot bolt  24  within the adjustment slot  36  of the associated hanger bracket  16 . The pivot bolt  24  and the nut  24  are tightened, and each spacer member  38  is then welded to the hanger bracket  16  at a plurality of locations  48  about the periphery of the associated spacer member  38 , thereby securely fixing the location and alignment of the axis  46  of the axle  29  with respect to the longitudinal axis of the vehicle frame  12 .  
         [0031]      FIGS. 5 and 6  best illustrate the prior art eccentric-type assembly  50  as previously discussed. The eccentric-type assembly  50  includes a pair of bosses affixed to the hanger bracket  16  opposed across the hanger bracket  16  from one another. Each boss  52  includes a raised rim  54 . The eccentric-type assembly  50  also includes an adjustment member  56  having a circumferentially extending groove  58  that receives the rim  54  of the associated boss  52  therein, and an off-center aperture  60  extending therethrough. Adjustment of the position of the axis  44  of the pivot bolt  24 , and therefore the position of the axis  46  of the axle  28 , is accomplished by rotating each adjustment member  56  with respect to the associated boss  52 , thereby forcing the axis  44  through an arcuate path  62 . It should be noted that the off-center location of the aperture  60  within each adjustment member  56 , while forcing the adjustment of the location of the axis  46  of the axle  28  with respect to the longitudinal axis of the vehicle frame  12 , also forces an adjustment of the axis  44  of the pivot bolt  24  in a vertical direction  64  and alters the relative positioning of the components of suspension system  10  with respect to one another in a vertical direction.  
         [0032]     The reference numeral  66  ( FIGS. 7-9 ) generally designates a first embodiment of the alignment adjustment assembly embodying the present invention. In the illustrated example, the alignment adjustment assembly  66  includes a pair of disc-shaped selector members  68  and a pair of engagement tabs  70 . As best illustrated in  FIGS. 7 and 10 , each selector member  68  includes a disc-shaped body portion  72  having an inner surface  74 , an outer surface  76 , and a circumferentially-extending outer edge  78 . Each selector member  68  also includes a plurality of U-shaped notches  80  extending inwardly into the inner surface  74  and the outer edge  78 , and spaced about the outer edge  78 . Each notch  80  is defined by an inner wall  84 , wherein each wall  84  defines an adjustment distance  85  between the wall  84  and a centroidal axis  86  of an aperture  88  extending through the selector members  68 . The adjustment distance  85  differs for each notch  80 . The outer surface  76  includes a square-shaped aperture  89  adapted to receive an adjustment tool therein. It should be noted that other configurations for the aperture  89  may be utilized to allow for the use of variously-configured wrenches and adjustment tools. A cylindrically-shaped boss  90  extends outwardly from the inner surface  74 , is concentrically-located about the centroidal axis  86 , and includes an arcuated extension  91  defining an end wall  93  and engagement walls  95 . Each tab  70  is cylindrically-shaped and is fixedly secured to hanger bracket  16 .  
         [0033]     In assembly, the boss  90  of each selector member  68  is located within the adjustment slot  36  of the hanger bracket  16 , such that the engagement walls  95  of each of the selector members  68  abut one another, thereby locking the same in rotation, and the tabs  70  engage oppositely-located notches  80  of the selector members  68 . It should be noted that other configurations for each boss  90  that do not require interlocking of the same may be utilized. The adjustment distance  85  as defined by the walls  84  of each of the notches  80  selectively positions the axis  44  of the pivot bolt  24  and the axis  86  of each of the selector members  68 , and therefore the axis  46  of the axle  28  with respect to the longitudinal axis of the associated vehicle. It should be noted that the tabs  70  and the notches  80  are located with respect to the hanger bracket  16 , and the associated selector members  68 , respectively, such that adjustment of the axis  44  and the axis  86 , and therefore the axis  46 , are done along a linear path with respect to the longitudinal axis of the vehicle frame  12 . Each selector member  68  is secured in a particular pre-selected position by securely tightening the pivot bolt  24  with the associated nut  42 . Alternatively, a spring member  92 , such as coil spring, may be positioned so as to bias each of the selector members  68  into engagement with the tabs  70 . In adjustment, the spring member  92  allows adjustment of the selector members  68  without requiring significant loosening of the associated nut  42 .  
         [0034]     The reference numeral  66   a  ( FIGS. 11 and 12 ) generally designates another embodiment of the alignment adjustment assembly of the present invention. Since the alignment adjustment assembly  66   a  is similar to the previously-described alignment adjustment assembly  66 , similar parts appearing in  FIGS. 7-10  and  FIGS. 11-13 , respectively are represented by the same, corresponding reference numeral except for the suffix “a” in the numerals of the latter. In the illustrated example, the alignment adjustment assembly  66   a  includes a pair of selector members  68   a  and a plurality of tabs  70   a . Each selector member  68   a  ( FIG. 13 ) includes a disc-shaped body portion  72   a  including an inner surface  74   a , an outer surface  76   a , and an outer edge  78   a  extending about the periphery thereof. Each selector member  68   a  also includes a centroidal axis  86   a  extending through a centrally-located aperture  88   a , and a cylindrically-shaped boss  90   a  concentrically located about the centroidal axis  86   a . A plurality of cup-shaped notches  94  extend inwardly from the outer edge  78  and are spaced about the periphery of the selector member  68 . A cam-wall  96  extends inwardly from the inner surface  74  and is inwardly spaced from the outer edge  78   a . The cam-wall  96  extends circumferentially about the centroidal axis  86   a  and defines a distance  98  that differs about the circumference of the selector member  68   a . Each tab  70   a  includes an inwardly-disposed, arcuately-shaped engagement surface  100 .  
         [0035]     In assembly, the boss  90   a  of each selector member  68   a  is located within the adjustment slot  36  of the hanger bracket  16 , such that the engagement walls  95   a  of each selector member  68  abut one another, thereby locking the same in rotation, and the tabs  70   a  engage oppositely-located notches  94  of the selector members  68   a , and abut opposing surfaces of the cam-wall  96 . The varying distance  98  as defined by the cam-wall  96  selectively positions the axis  44  of the pivot bolt  24  and the axis  86   a  of each of the selector members  68   a , and therefore the axis  46  of the axle  28 , with respect to the longitudinal axis of the associated vehicle. It should be noted that the tabs  70   a  and the centroidal axis  86   a  of the selector members  68   a  are located with respect to the hanger bracket  16 , such that adjustment of the axis  44  and the axis  86 , and therefore the axis  46 , are done along a linear path with respect to the longitudinal axis of the vehicle frame  12 . Each selector member  68   a  is secured in a particular pre-selected position by securely tightening the pivot bolt  24  with the associated nut  42 . Alternatively, a spring member  92   a , such as coil spring, may be positioned so as to bias each of the selector members  68   a  into engagement with the tabs  70   a . In adjustment, the spring member  92   a  allows adjustment of the selector members  68   a  without requiring significant loosening of the associated nut  42 .  
         [0036]     In the foregoing description, it will be readily appreciate by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless the claims by their language expressly state otherwise.