Abstract:
The present invention provides an eccentric pivot member for effecting fore and aft movement of a leading end of a trailing beam member of a trailing beam suspension in response to rotation of the pivot member. Ratchet collars are provided which act between the eccentric pivot member and a suspension hanger to mechanically secure the assembly against rotation and any associated inadvertent misalignment.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to vehicle suspension assemblies. More particularly, the invention relates to axle mounting assemblies for trailers. Still more particularly the present invention relates to alignment apparatus for a trailing beam hanger assembly. 
     BACKGROUND OF THE INVENTION 
     A trailing beam suspension typically utilizes a beam having a leading end opposite a trailing end. The beam is mounted lengthwise to a hanger at its leading end for swinging movement about an axis transverse to a trailer. The hanger is typically secured to a chassis or frame of the trailer by suitable means such as welding. A suspension unit such as an air bag extends between the trailing end of the beam and the chassis of the trailer. An axle is mounted to the beam transverse to the beam between the leading and trailing ends of the beam. 
     The above suspension arrangement is referred to as a “trailing beam” suspension because the beam extends rearwardly from its connection to the hanger and accordingly the axle “trails” the pivot point of the suspension system. 
     In assembling a trailer, there is a need, because of manufacturing tolerances, to provide for some fore and aft adjustment of the axle relative to the hanger to ensure that the axle is orthogonal to a centre line of the trailer. In its simplest form, the adjustment may simply be effected by providing slots in the hangers for receiving a pivot member about which the beam swings to enable fore/aft movement of the pivot member during assembly subsequent to which the components may be secured by friction (bolting), welding or both. 
     A disadvantage with simply providing a slot to enable movement is that it lacks apparatus for effecting the movement. Accordingly, external force needs to be applied to the beam or the axle to move the pivot member fore and aft. This makes minute adjustments somewhat difficult. 
     Screw type adjusters which act between the pivot member and the hanger have been proposed, however, such adjusters must be made quite robust and as well, the hanger suitably braced, for such to be effective. In any case, the screw generally cannot be relied upon to control fore/aft movement and accordingly, absent welding the components in place after adjustment, there is a risk of movement of the pivot member in the slot and ensuing misalignment. 
     Its is an object of the present invention to provide a trailing beam hanger and alignment apparatus which overcomes at least some of the problems associated with prior devices. 
     SUMMARY OF THE INVENTION 
     The present invention provides an eccentric pivot member for effecting fore/aft movement of the leading end of the beam in response to rotation of the pivot member. Ratchet collars are provided to mechanically secure the assembly against rotation and any associated inadvertent misalignment. 
     More particularly, a mounting and alignment apparatus is provided for a trailing beam hanger having walls at least partially defining a box with an opening for receiving a leading end of the trailing beam. The hanger is securable to a trailer with the opening facing in a rearward direction. The walls include a pair of spaced apart sidewalls for receiving the leading end of the trailing beam therebetween. The apparatus includes an eccentric pivot bolt having a center section between threaded, generally coaxial end sections. The center section is larger in diameter than the end sections and has a center section axis generally parallel to but non-coaxial with an axis of the end sections. The center section of the eccentric pivot bolt is receivable in a rigid center tube of a bushing mounted in a passage extending transversely through the leading end of the trailing beam. A first ratchet collar extends about and is secured to one of the end sections. The first ratchet collar has a flange extending through the passage to abut the center tube. A second ratchet collar is rigidly secured to the eccentric pivot bolt. The second ratchet collar has a grippable portion associated therewith for facilitating rotation of the second ratchet portion along with the eccentric pivot bolt about the axis of the end section. The first and second ratchet collars engage each other to provide at least unidirectional rotation of the second ratchet collar relative to the first ratchet collar. A hanger side reinforcement extends about the other of the end sections, the hanger side reinforcement has a raised collar for extending through an adjacent of the thrust washers to abut against the center tube. A nut threadedly engages the other of the end sections for acting against the hanger side reinforcement to urge the first and second ratchet collars toward each other to secure the ratchet collars and in turn the pivot bolt against rotation. 
     The apparatus may include a spring extending between the nut and the hanger side reinforcement. 
     A washer may extend between the nut and the spring. 
     The spring may be one or more disc springs. 
     The grippable portion may be a nut welded to the second ratchet collar. 
     The center tube is surrounded by a resilient material to provide cushioning between the hanger and the beam. 
     The first and second ratchet collars may have teeth which mesh with each other and which are profiled to cause unidirectional rotation corresponding with a tightening direction of the nut to restrain the ratchet collars from moving relative to each other in such a manner as to cause loosening of the components of the apparatus. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings wherein: 
         FIG. 1  is a view of a trailing beam incorporating a mounting and alignment apparatus according to the present invention; 
         FIG. 2  is an exploded view of the mounting and alignment apparatus of  FIG. 1 ; 
         FIG. 3  is a perspective view of one of multiple bushing types that may be used with various suspension models; 
         FIG. 4  is a front elevation of the bushing of  FIG. 3 ; 
         FIG. 5  is an end elevation of the bushing of  FIG. 3 ; 
         FIG. 6  is a front plan view of an eccentric pivot bolt according to the present invention; and, 
         FIG. 7  is an end elevation corresponding to  FIG. 6 . 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     A trailing beam mounting alignment apparatus according to the present invention is generally indicated by reference  10  in the accompanying illustrations. The apparatus  10  includes a hanger  20  having a forward wall  22 , opposite sidewalls  24  and an upper wall  26  which partially define an opening  28  which receives a leading end  32  of a trailing beam  30 . The leading end  32  is mounted between the sidewalls  24  and supported thereby. 
     An eccentric pivot bolt  40  mounts the trailing beam  30  to the hanger. The pivot bolt  40  is insertable through an opening  25  in one of the sidewalls  24 . The pivot bolt  40  has a center section  42  between two end sections  44  and  46 . The two end sections  44  and  46  are threaded and generally coaxial with each other. The center section  42  has an axis  43  which is generally parallel to a common axis  45  of the end sections  44  and  46  and its axis would revolve about the axis  45  of the end sections in response to rotation of the end sections  44  and  46  about their axis  45 . In response, the axis  43  of the center section  42  can move fore and aft of the axis  45  of the end sections. 
     The leading end  32  of the trailing beam  30  has a transversely extending passage  34  which receives a bushing  50 . The bushing  50  typically has a resilient shell  54  of an elastometric material surrounding a rigid tubular, typically steel, center tube  52 . The center tube  52  in turn receives the center section  42  of the pivot bolt  40 . The bushing  50  both mounts the leading end  32  to the hanger  20  and isolates the hanger from road shock transmitted along the trailing beam  30 . 
     Respective wear discs  60  extend about the end sections  44  and  46  on opposite sides of the leading end  32  of the trailing beam  30 . The wear discs  60  have an opening  62  having a diameter at least as large as the ends of the center tube  52  of the bushing  50  so as not to interfere with the center tube  52 . 
     A first ratchet collar  70  extends about the end section  46  of the pivot bolt  40  adjacent an outer face of one of the sidewalls  24 , to which it is secured (welded). The first ratchet collar  70  has a flange  71  extending through opening  25  in the adjacent sidewall  24  to abut bushing  50 . The first ratchet collar  70  has outwardly facing teeth  72 . A second ratchet collar  74  is mounted over the same end section  46  as is the first ratchet collar  70 . The second ratchet collar has inwardly facing teeth  76  which face and engage with the outwardly facing teeth  72  of the first ratchet collar  70 . The first and second ratchet collars,  70  and  74  respectively, fit closely over the end section  46 . The flange  71  fits closely within the opening  62 . 
     The second ratchet collar  74  may be welded to a nut  80  which is in turn welded to the end section  46 . The nut  80  provides a grippable portion associated with the second ratchet collar  74  to facilitate co-rotation of the pivot bolt  40  and the second ratchet collar  74 . Other arrangements are no doubt possible, such as, providing facets on the second ratchet member  74  or welding the nut to the pivot bolt  40  directly without welding it to the second ratchet member  74 . Basically, what is desired is some provision to facilitate rotation of the pivot bolt, preferably using a simple tool, such as a wrench. 
     The teeth  72  and  76  of the first and second ratchet collars  70  and  74  respectively are preferably configured to allow rotation of the first and second ratchet collars relative to each other in a tightening direction and to block rotation in the opposite, loosening direction. As discussed below, such an arrangement ensures against loosening of the apparatus. 
     A hanger side reinforcement  90  is welded to the sidewall  24 , aligning passage  92  with opening  29  in hanger sidewall. The hanger side reinforcement  90  is a cylindrical disc having a passage  92  therethrough for receiving the end section  44 . The opening in the sidewall  25  should be large enough to admit the end section  44  of the pivot bolt  40  therethrough. The opening in the hanger would typically be sized to closely receive the end section  44  it surrounds to constrain the end section  44  against fore and aft movement (toward and away from the forward wall  22 ). Accordingly, rotation of the end sections  44  &amp;  46  about their axes will result in fore and aft movement of the center section  42  and in turn, fore and aft movement of the trailing beam  30 . 
     One or more disc springs  100  are mounted over the end section  44  outboard of the hanger side reinforcement  90 . Two are illustrated. Resilient means other than a disc spring may be workable. The disc springs  100  should, preferably in an uncompressed state, allow enough axial movement of the pivot bolt  40  to enable the teeth of the first and second ratchet members,  70  and  74  respectively, to move into and out of meshing engagement. 
     A washer  110  and locknut  120  complete the assembly. The washer  110  mounts over the end section  44 , engages the disc spring  100  on one side and is engaged by the locknut  120  on its opposite side. The locknut  120  threadedly engages the end section  44 . Tightening the locknut  120  causes the disc springs  100  to be compressed into a collapsed configuration and urges the first and second ratchet collars,  70  and  74  respectively, toward each other to lock the pivot bolt  40  against rotation. Preferably the teeth  72  and  76  of the first and second ratchet collars  70  and  74  respectively are configured (profiled) to block rotation in the loosening direction of the pivot bolt  40  and locknut  120 , assembly. The trailing beam  30  should be firmly mounted in the hanger  20  without binding and without excessive side-play. Accordingly, the amount of clamping force applied to the center tube  52  of the bushing  50  should be controlled, for example, by having the flange  71  and the sidewalls  24  abut against respective ends of the center tube  52  of the bushing  50 . Assuming the flange  71  and sidewalls  24  are correctly dimensioned, the spring washers  100  and the hanger side reinforcement  90 , which is welded to hanger side  24  and the tightening of the locknut  120  compresses the center tube  52  against the ratchet collar  70  and the hanger sidewall  24 .