Abstract:
A system and method for adjusting at least one of a camber and a caster of a suspension system. The system includes a lower control arm and a suspension member coupled to the lower control arm. The system also includes a plate or plates defining a slot, the slot having a cam retaining element. In addition, the system includes one or more cams retained by the cam retaining element, the cam or cams defining an off-axis opening. The system also includes a bolt extending through the slot and through the off-axis opening in the cam. Upon rotation of the cam, the at least one plate is caused to move relative to the suspension member, which in turn causes the suspension member to move relative to the lower control arm.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an off-axis cam adjustment system and method. More specifically, the present invention relates to a lower control arm camber and caster adjustment mechanism for a suspension system. 
     BACKGROUND INFORMATION 
     Conventional suspension systems, such as for motor vehicles, typically provide a camber and a caster to the wheels of the motor vehicle. Camber is the setting of the wheels closer together at the bottom than at the top. Caster is the angle of the steering axis of a wheel from its vertical viewed from a lateral side of the vehicle, and usually is manifested by a slight, typically backwards, tilt of the upper end of a kingbolt for giving directional stability to the front wheels. 
     Conventional suspension systems typically enable the camber and caster of the wheels to be adjusted. These adjustments are often necessary due to the shocks and vibrations experienced by the motor vehicle, which may tend to cause the camber and caster of the wheels to change, thereby requiring realignment. Several types of suspension systems provide such adjustability. One such type of conventional suspension, such as that shown and described in U.S. Pat. No. 6,367,826 entitled “Camber/Caster Adjuster,” includes an alignment adjuster for wheel alignment of a motor vehicle, in which the alignment adjuster includes a shaft that is moveable within an elongated slot. The adjustable member is a lower control arm that is attached via a bushing to the shaft. The shaft includes a pinion gear that contacts a rack element that is disposed near the elongated slot. Rotation of the shaft initiates lateral movement of the shaft in the elongated slot. 
     However, conventional camber and caster adjustment mechanisms do not provide sufficient precision with respect to adjustability. Furthermore, conventional camber and caster adjustment mechanisms do not provide sufficient ease of adjustment. 
     Therefore, there exists a need for an improved camber and caster adjustment mechanism for the suspension system of a motor vehicle. 
     It is therefore an object of the present invention to provide an improved camber and caster adjustment mechanism for the suspension system of a motor vehicle. 
     It is another object of the present invention to improved the precision with which the camber and caster of the suspension system of a motor vehicle may be adjusted. 
     It is still another object of the present invention to increase the amount by which the camber and caster of the suspension system of a motor vehicle may be adjusted. 
     It is still another object of the present invention to provide a camber and caster adjustment mechanism for the suspension system of a motor vehicle that is easier to adjust than conventional camber and caster adjustment mechanisms. 
     SUMMARY OF THE INVENTION 
     The above and other beneficial objects of the present invention are achieved by providing a system and method as described herein. The present invention, according to one example embodiment thereof, relates to a system and method for adjusting at least one of a camber and a caster of a suspension system, such as for a motor vehicle. The system includes a lower control arm and a suspension member coupled to the lower control arm. The system also includes a plate or plates including a slot, the slot having a cam retaining element. In addition, the system includes one or more cams retained by the cam retaining element, the cam or cams providing an off-axis opening. The one or more cams may be round. The system also includes a bolt extending through the slot and through the off-axis opening in the cam. Upon rotation of the cam, the at least one plate is caused to move relative to the suspension member, which in turn causes the suspension member to move relative to the lower control arm. 
     In one example embodiment, the system includes a pair of plates, each of the plates including slots, and each of the slots having cam retaining elements. The system may also include a pair of cams retained by the cam retaining elements, each of the pair of cams providing an off-axis opening. In this manner, the rotation of the cams cause the pair of plates to move evenly relative to the suspension member which in turn causes the suspension member to move evenly relative to the lower control arm. The cam retaining elements may include a pair of elements that are elevated relative to a surface of the plates. The pair of elevated elements are disposed at a distance from each other that is equal to, or slightly less than, an outer diameter of the pair of cams, such that the cams may fit rotatably therein. 
     The system may also include a second suspension member coupled to the lower control arm in, e.g., the same manner that the first suspension member is coupled thereto. In this example embodiment, the system is configured such that relative movement of the lower control arm with respect to both the suspension member and the second suspension member causes an adjustment to the camber of the suspension system, while relative movement of the lower control arm with respect to one of the suspension member and the second suspension member causes an adjustment to the caster of the suspension system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view that illustrates various elements of an off-axis cam adjustment system, in accordance with one example embodiment of the present invention; 
         FIG. 2  illustrates an assembled view of the system illustrated in  FIG. 1 , viewed from right front perspective; and 
         FIG. 3  illustrates an assembled view of the system illustrated in  FIG. 1 , viewed from left front perspective. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an exploded view of a system  10 , e.g., an adjustment mechanism, for the suspension system of an automobile, according to one example embodiment of the present invention. In the example embodiment shown, the system  10  includes an upper suspension cross-member component  12  that mates with a lower suspension cross-member component  14  to form a suspension cross-member  15 . The lower suspension cross-member component  14  has a pair of vertically-disposed sidewalls  141 ,  142 . The sidewalls  141 ,  142  include respective slotted openings  143 ,  144  that are disposed so as to be generally opposite from each other. In addition, the sidewalls  141 ,  142  include respective round openings  145 ,  146  that are disposed so as to be generally opposite from each other. 
     The system  10  also includes a lower control arm  16  that is configured to engage the suspension cross-member  15 . Specifically, the lower control arm  16  includes a first arm  161  and a second arm  162  that extend from the lower control arm  16 . The first arm  161  and the second arm  162  are disposed so as to be generally parallel relative to each other at a predetermined distance from each other. The first arm  161  has an orifice, e.g., hexagonally-shaped, that is configured to receive a corresponding and complementary end, e.g., hexagonally-shaped, of a torsion bar  18 . The second arm  162  has an opening  164  that is configured to receive a lower control arm bushing  36 . The lower control arm bushing  36  has an axial bore  361 . The lower control arm  16  also has a third arm  165 . In addition, the third arm  165  of the lower control arm  16  is configured to adjustably couple to a second suspension cross-member  40  of the suspension system. However, for the purposes of clarity, the specific details of the adjustment mechanism for this second suspension cross-member are not shown in FIG.  1 . The second suspension cross-member  40  may include an adjustment mechanism, which may be similar to the mechanism provided and described herein with respect to the suspension cross-member  15 . 
     The system  10  also includes a first reaction plate  20  and a second reaction plate  22 . The first reaction plate  20  has a surface  201  that is configured to abut the outer surface of the vertically-disposed sidewall  141  of the lower suspension cross-member component  14 . The surface  201  and the outer surface of the sidewall  141  may be flat. Furthermore, the first reaction plate  20  has an operative surface  203  disposed on the opposite side of the first reaction plate  20 . The first reaction plate  20  also includes a slot  202 . At opposite ends of the slot  202  are a pair of cam retaining elements  204 ,  205  that are slightly elevated relative to the operative surface  203 . The first reaction plate  20  also includes a through-hole  206 . Mounted over the through-hole  206 , on the operative surface  203 , is a threaded boss  207 . 
     The second reaction plate  22  has a flat surface  221  that is configured to abut the outer surface of the vertically-disposed sidewall  142  of the lower suspension cross-member component  14 . The surface  221  and the outer surface of the sidewall  141  may be flat. Furthermore, the second reaction plate  22  has an operative surface  223  disposed on the opposite side of the second reaction plate  22 . The second reaction plate  22  also includes a slot  222 . At opposite ends of the slot  222  are a pair of cam retaining elements  224 ,  225  that are slightly elevated relative to the operative surface  223 . The second reaction plate  22  also includes a through-hole  226 . 
     The system  10  also includes a bolt  26  having a head  261  and a threaded end  262 . A first cam  24  is configured to be disposed on the bolt  26  adjacent to the head  201 , and a second cam  30  is configured to be disposed on the threaded end  262  of the bolt  26  and to be held in place by a nut  32 . The first and the second cams  24 ,  30  have off-axis openings  241 ,  301 , respectively, disposed therethrough, e.g., the off-axis openings  241 ,  301  are not positioned in the center of the first and second cams  24 ,  30 . In addition, the first and the second cams  24 ,  30  have outer diameters that are approximately equal to or slightly less than the distance between the cam retaining elements  204 ,  205  of the first reaction plate  20  and the cam retaining elements  224 ,  225  of the second reaction plate  22 , respectively. It should be understood that, while the preferred example embodiment of the present invention includes cams  24 ,  30  that are round, other shapes may be provided. 
     The system  10  also includes a sleeve  34  having an axial bore  341  with an inner diameter slightly larger than the outer diameter of the bolt  26 . The sleeve  34  has a length which is approximately equal to or slightly less than the distance between the inner surfaces of the vertically-disposed sidewalls  141 ,  142  of the lower suspension cross-member component  14 . The system  10  also includes a bolt  28  having a head  282  and a threaded end  281 . The threaded end  281  of the bolt  28  is configured to extend through the through-hole  226  of the second reaction plate  22 , through the slots  143 ,  144  of the sidewalls  141 ,  142 , respectively, through the axial bore  361  of bushing  36 , and to engage the threaded boss  207  on the operative surface  203  of the first reaction plate  20 . 
       FIGS. 2 and 3  illustrate assembled views of the system  10  illustrated in  FIG. 1 , viewed from right front perspective and the left front perspective, respectively. As shown in  FIG. 2 , the upper suspension cross-member component  12  mates with the lower suspension cross-member component  14  to form the assembled suspension cross-member  15 . The suspension cross-member  15  is configured to be fixedly attached to the motor vehicle. The surface  201  of the first reaction plate  20  is positioned against the outer surface of the vertically-disposed sidewall  141  of the lower suspension cross-member component  14  such that the through-hole  206  and the slot  206  of the first reaction plate  20  line up with the slot  143  and the hole  145  of the sidewall  141 , respectively. Likewise, the flat surface  221  of the second reaction plate  22  is positioned against the flat outer surface of the vertically-disposed sidewall  142  of the lower suspension cross-member component  14  such that the through-hole  226  and the slot  222  of the second reaction plate  20  line up with the slot  144  and the round hole  146  of the sidewall  142 , respectively. The bolt  26  is inserted through the off-axis opening  241  in the first cam  24 , through the slot  202  of the first reaction plate  20 , through the hole  145  in the sidewall  141 , through the axial bore  341  of the sleeve  34 , through the slot  222  of the second reaction plate  22  and through the off-axis opening  301  of cam  30 . The nut  32  engages the threaded end  32  of the bolt  26 . When the nut  32  is tightened on the threaded end  262  of the bolt  26 , the cams  24 ,  30  are maintained in position against the operative surfaces  203 ,  223  of the first and second reaction plates  20 ,  22 , respectively. In addition, the cam  24  is maintained between the cam retaining elements  204 ,  205  of the first reaction plate  20 , while the cam  30  is maintained between the cam retaining elements  224 ,  225  of the second reaction plate  22 . 
     In addition, the lower control arm  16  is adjustably coupled to the suspension cross-member  15 . Specifically, the lower control arm bushing  36  is inserted into the opening  164  in the second arm  162  of the lower control arm  16 . The bolt  28  is inserted through the through-hole  226  of the second reaction plate  22 , through the slot  144  of the sidewall  142 , through the axial bore  361  of the lower control arm bushing  36 , through the slot  143  of the sidewall  141 , and through the through-hole  206  of the first reaction plate  20 . The threaded end  281  of the bolt  28  engages the threaded boss  207  mounted on the operative surface  203  of the first reaction plate  20 , and is tightened to maintain the lower control arm  16  coupled to the suspension cross-member  15 . 
     As previously stated, the system  10  may provide a adjustment mechanism for the suspension system of an automobile, according to one example embodiment of the present invention. More specifically, the system  10  may provide adjustability of the camber and caster of the lower control arm  16 . In order to perform such an adjustment, the nut  32 , which is typically maintained tightly on the bolt  26 , is loosened slightly. Next, the bolt  28 , which is typically maintained tightly by the threaded boss  207 , is also loosened slightly. The position of the lower control arm  16  relative to the suspension cross-member  15  is then adjusted by the turning of the first or second cam  24 ,  30  in a selected direction. Turning the bolt  26  causes the cams  24 ,  30  to rotate around the center of the off-axis openings  241 ,  301  defined by the cams  24 ,  30 . Because the openings  241 ,  301  are off-axis, and because the bolt  26  is maintained within openings  145 ,  146  of the sidewalls  141 ,  142 , the turning movement of the cams  24 ,  30  causes horizontal movement of the first and second reaction plates  20 ,  22 , respectively. Furthermore, the horizontal movement of the first and second reaction plates  20 ,  22  causes the bolt  28 , which is fixedly attached to the lower control arm  16 , to move horizontally within the slots  143 ,  144  of the sidewalls  141 ,  142 , respectively. In this manner, the suspension cross-member  15  is caused to move relative to the lower control arm  16 . 
     An adjustment may also be made, in like or different fashion, with respect to the third arm  165  of the lower control arm  16  and the second suspension cross-member  40 , depending on the desired adjustment to the camber and caster. Specifically, if it is desired to change only the camber of the suspension system, then an adjustment may be made to the lower control arm  16  with respect to both the suspension cross-member  15  and the second cross-member  40  that is adjustably coupled to the third arm  165  of the lower control arm  16 . If, on the other hand, it is desired to change both the camber and the caster of the suspension system, then an adjustment may be made to the lower control arm  16  with respect to one or the other of the suspension cross-member  15  and the second cross-member  40 . Once the desired camber or caster is achieved, the bolt  28  is tightened with respect to the threaded boss  207 , while the first and second cams  24 ,  30  are held in position. Next, the first and second cams  24 ,  30  are locked into position by tightening the nut  32  on the threaded end  262  of the bolt  26 . 
     The system  10  may improve the precision with which the lower control arm  16  may be adjusted relative to the suspension cross-member  15 . For instance, the turning of the first and second cams  24 ,  30  in order to cause the first and second reaction plates  20 ,  22  to move horizontally may enable precise adjustments of the position of the lower control arm  16  relative to the suspension cross-member  15 . In addition, the system  10  may provide an additional amount of camber and caster adjustment compared to the conventional camber and caster adjustment mechanisms for suspension systems. Depending on the diameter of the cams  24 ,  30  and on the distance between the off-axis openings  241 ,  301  and the actual center axes of the cams  24 ,  30 , the system  10  of the present invention may enable the suspension cross-member  15  to move relative to the lower control arm  16  a significantly larger distance than conventional suspension systems, thereby enabling a larger adjustment to the camber and caster of the wheels of the motor vehicle. 
     Furthermore, the use of the off-axis openings  241 ,  301  in the first and second cams  24 ,  36  prevents the cams from slipping, and thus the position of the lower control arm  16  relative to the suspension cross-member  15  from changing inadvertently, when the first and second cams  24 ,  30  are being tightened. Cams may have a tendency to slip when being tightened in a conventional camber and caster adjustment mechanisms of this type. 
     Still further, the system  10  may not require the use of a back-up wrench when tightening the bolt  28 . Conventional adjustment mechanisms of this type may require that an operator employ a back-up wrench in order to tighten a bolt that holds a lower control arm in position relative to a suspension cross-member. However, the position of the torsion bar  18  in a conventional in-line torsion bar system renders it very difficult to use a back-up wrench on a nut at the end of the bolt  28 . In contrast, in accordance with one example embodiment of the present invention, the bolt  28  engages the threaded boss  207  on the operative surface  203  of the first reaction plate  20 . The threaded boss  207  is fixedly attached to the operative surface  203  of the first reaction plate  20  and thus does not rotate. As a result, the bolt  28  may be tightened without requiring that the threaded boss  207  be held in place by a back-up wrench. 
     Thus, the several aforementioned objects and advantages of the present invention are most effectively attained. Those skilled in the art will appreciate that numerous modifications of the exemplary embodiments described hereinabove may be made without departing from the spirit and scope of the invention. Although various exemplary embodiments of the present invention have been described and disclosed in detail herein, it should be understood that this invention is in no sense limited thereby and that its scope is to be determined by that of the appended claims.