Abstract:
A suspension hanger assembly for receiving the bush end of a control arm is provided for adjusting axle alignment, without vertical displacement, and includes spaced-apart sides; each having aligned bores for a spindle, a bush pin and a fastening bolt. Two cams, having openings for the spindle, bush pin and fastening bolt, are aligned with the bracket bores. The bush pin bore of the bracket is horizontally elongated limiting vertical displacement of the bush pin. The fastening bolt opening of each cam is arcuate-shaped which allows cam actuation in an eccentric pattern. As the cam is moved, the bush pin moves horizontally respective to the bracket. The control arm bush is secured via the bush pin and fastening bolt. The control arm is fixed to the axle and horizontal movement of the control arm within the hanger bracket results in linear movement of that axle respective to the vehicle chassis.

Description:
FIELD OF INVENTION 
     The present invention is directed to a suspension hanger having an adjustment cam which provides limited horizontal adjustment for alignment of an axle relative to a vehicle chassis. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to an adjustable suspension hanger, which allows limited adjustment, within the horizontal plane, for alignment of the vehicle axle in relation to the vehicle chassis, a control arm and axle attachment assembly, which facilitates ease of adjustment, removal and replacement of the axle. 
     A common reoccurring problem in vehicle suspension systems is misalignment of the axle in relation to the vehicle chassis. Such misalignment contributes to increased tire and axle component wear. Further, significant misalignment can adversely impact the steerability of the vehicle potentially resulting in lost control. 
     The known methods and systems for vehicle suspension alignment, particularly heavy truck and trailer suspensions, generally involve lengthy and complex manipulation or adjustment of the suspension itself or require welding, drilling, or additional fastening of suspension components. It is not uncommon, on heavy-duty suspensions, to eliminate undesirable axle travel or misalignment, by welding the control arm fastener to the hanger bracket once alignment is achieved. Some manufacturers choose not to provide any alignment adjustment at the hanger bracket but rather rely on achieving permanent alignment at the time of manufacture. On many systems it is necessary to remove all, or a portion of the axle assembly to replace or add parts to ensure appropriate alignment. Preferably, the alignment operation is performed without removing any components or parts from the vehicle and should be convenient and inexpensive. 
     Particular problems exist in alignment of heavy-duty axles or suspension systems utilized in commercial, high load, vehicles. Unlike passenger vehicles, commercial vehicles generally have heavy-duty axles and suspensions which are difficult to maneuver or adjust and are generally expensive to repair. Any alignment system which requires welding, removal of components, replacement of components, or suspension disassembly is undesirable. Common axle alignment methods often require partial disassembly of the suspension mechanism, particularly at the hanger, and require the insertion or extraction of shims between the control arm bush and the hanger bracket. 
     It is also common to find large eccentric bores formed through the vehicle hanger bracket which, when the control arm pin is fitted with large washers or cams, allow significant movement of the control arm bush within the hanger bracket. While only horizontal displacement of the axle relative to the vehicle chassis is desirable during the alignment process, it is common to experience vertical displacement of the axle with known systems utilizing a large eccentric bore and compression bolts, or similar fasteners, to facilitate alignment. 
     Alignment of these relatively simple systems typically requires loosening the bush pin, or compression bolt, and manipulating the control arm within the confines of the bore provided through the hanger. When the desired positioning is acquired, the fastener is secured and will generally retain the control arm position within the hanger. However, any undesirable vertical movement of the control arm and attached axle relative to the vehicle chassis imparts uneven force on the vehicle frame, which results in vertical frame misalignment. 
     Moreover, most alignment methods often require significant trial and error to find the desired alignment as they lack means for manipulating the control arm within the bracket. A typical method for aligning would include raising the vehicle from the ground, loosening the control arm bush pin and applying significant horizontal force to the vehicle axle, such as with a ram or hammer. 
     At this time, there are no known suspension assemblies which allow easy and inexpensive horizontal alignment of heavy duty, commercial grade, axles. It is therefore desirable to provide an axle alignment system which is easy to operate, which eliminates vertical displacement of the axle during alignment and which does not require any disassembly or replacement of parts. It is also desirable to provide a heavy-duty axle alignment system which eliminates welding. Further, it is desirable to provide an axle alignment system which, when positioned and correctly fastened, eliminates unwanted movement which results in misalignment. 
     The present invention addresses the above described problems and limitations standard in the art by providing a suspension hanger mechanism which allows easy, inexpensive and secure horizontal alignment of the vehicle axle relative to the vehicle chassis. A specially formed cam mounted to the suspension hanger bracket allows limited horizontal adjustment of the control arm bush within the hanger bracket assembly. A series of uniquely designed spaced-apart bores within the hanger bracket and the cam eliminate undesirable vertical displacement during the alignment process. Further, multiple fastening points through the hanger bracket and cam limit unintentional displacement of the axle during use. 
     DISCLOSURE OF THE INVENTION 
     The present invention addresses the above described problem and limitations standard in the art by providing a suspension hanger mechanism which utilizes a specially formed cam mounted to the suspension hanger bracket to facilitate easy adjustment of the control arm bush within the hanger bracket assembly. The adjustment system provides a series of uniquely designed spaced-apart bores within the hanger bracket and the cam to allow alignment without suspension disassembly and to eliminate undesirable vertical displacement during the alignment process. 
     A suspension hanger bracket is fixed in a typical downward orientation to a vehicle cross member or chassis. The hanger bracket has opposing sides configured to receive the bush end of a suspension control arm. Substantially near the lower edge of each hanger bracket side, a plurality of bores are provided. The bores include, starting at the top, a horizontally elongated bush pin bore and a fastener bore. The bores of each hanger side are in axial alignment with the bores of the opposing side. A bush end of a suspension control arm is received between the opposed sides of the hanger bracket, orientated so that the horizontally elongated bush pin bore is in axial alignment with the pin hole in the control arm bush. To reduce the possible deformation of the hanger bracket sides, it is preferable to install a reinforcement plate on each hanger bracket side over the series of bores. It is preferable that the reinforcement plate be of hardened steel and it must be provided with a spindle bore along with a horizontally elongated pin bore and fastening bore of the same size and orientation as those described in the bracket side. 
     A specially shaped cam facilitates fore and aft adjustment of the suspension control arm within the hanger bracket. The cam, preferably spade shaped, is provided with a series of openings commensurate with the hanger bracket and reinforcement plate bores. The cam has a spindle opening, a bush pin opening and an arcuate-shaped fastener opening. 
     A cam is positioned on the outside face of both opposed hanger bracket sides so that the series of cam openings are aligned with the series of bracket and reinforcement plate bores. Prior to positioning the control arm bush in the hanger bracket, short fasteners, preferably hardened carriage bolts, are fitted from inside the hanger brackets through the reinforcement plate fastener bore and the arcuate shaped fastening opening within the cam. It is preferred that the fastener bore of the reinforcement plate is square to prevent turning of the carriage bolt once it is in place. Use of the reinforcement plate allows the carriage bolt head to be recessed into the hanger bracket side to avoid contact between the bolt and the control arm bush. 
     The bush end of the control arm is positioned between the opposed bracket sides and a bush fastener is fitted through the bush pin opening through the cam and the horizontally elongated bush pin bores of the opposed bracket sides and reinforcement plates. A short spindle is movably positioned within the spindle opening of each cam into the spindle bore of the reinforcement plate. The spindle may be welded or preformed onto the cam. 
     A square opening is formed in the cam, substantially adjacent the fastening opening. When the bush pin and the fastening bolt are loosened, the control arm bush can be manipulated horizontally within the hanger bracket by applying force to the square opening with a breaker bar. The cam moves in an eccentric circuit due to the arcuate-shaped fastener opening. The cam moves about the fastening bolt which is retained within the fastening bore of the reinforcement plate. The bush pin opening of the hanger bracket prevents vertical displacement of the bush pin relative to the hanger while allowing horizontal displacement of the bush pin within the horizontally elongated bush pin bore in the hanger bracket sides. The spindle provides a pivot about which the. cam moves. The arcuate-shaped fastener opening compensates for, and eliminates vertical displacement, by allowing the cam to travel an eccentric circuit while maintaining the bush pin within a horizontal plane defined by the horizontally elongated bush pin bore the hanger bracket. 
     When the desired alignment of the axle is achieved, determined by the control arm bush orientation within the hanger bracket, the bush pin and fastening bolts are tightened. The fastener bolts and bush pin provide two distinct compression points which secures the control arm bush relative to the bracket and greatly reduces the potential for undesired displacement during vehicle operation. 
     When the axle is aligned and the bush pin and fastening bolts are secured, significant pressure should be exerted to maintain control arm bush positioning. The suspension hanger is also provided with an upper shock absorber bracket, preferably on the inboard side, substantially near the mounting plate. 
     As the control arm is fixed to the axle any change in relation between the bush end of the control arm in the suspension bracket results in linear forward or rearward movement of that axle with respect to the vehicle chassis. 
     Each suspension system requires two opposed hanger brackets positioned on either side of the vehicle chassis. It is understood that the disclosure herein specifically describes a single hanger bracket and the second hanger bracket would be a mirror image of the first. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a one embodiment of the inventive vehicle suspension hanger. 
     FIG. 2 is an exploded view of one embodiment of the inventive vehicle suspension hanger. 
     FIG. 3 is a perspective view of the suspension hanger adjustment cam. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     This suspension alignment system is designed for installation on a vehicle, preferably heavy trucks, trailers and commercial equipment, having a pair of substantially parallel chassis side rails with a plurality of cross-members there between. It is understood that the suspension assembly is duplicated on both sides of the chassis with the axle as well as the chassis being similarly connected to both assemblies. Since each suspension assembly is identical, only a single assembly will be described. 
     Referring now to FIG. 1, a hanger bracket assembly  102  is provided which is preferably formed from hardened plate steel. A mounting plate  104 , which is preferably welded to the chassis  100 , is also provided with a plurality of mounting holes for bolting the assembly to a vehicle chassis. The mounting plate secures the hanger bracket assembly to the vehicle and is utilized to strengthen attachment points on the hanger bracket assembly. A control arm  154  extends from the hanger assembly and attaches to a spaced-apart axle  160 . An air spring  168 , or a similar spring mechanism is mounted substantially above the control arm  154  at its most rearward position and to the vehicle chassis  100 . 
     As shown in FIGS. 1 and 2, an inboard hanger side  106  is fixed perpendicularly to the mounting plate  104  in a generally downward orientation. An outboard hanger side  108  is also fixed perpendicular to the mounting plate and is parallel and in alignment with the inboard hanger side  104 . 
     The outboard hanger side  108  may be used to form a frontal plate  110  by bending the material of the outboard hanger side  108  approximately 90 degrees and fixing the bent portion  111  of the frontal plate  110  to the mounting plate  104  and the inboard hanger side  106 . Further, the frontal plate  110  may extend beyond and perpendicular to the inboard hanger side  106  to form a lateral flange  112  which reduces the flex of the hanger, particularly during vehicle braking and cornering. 
     The inboard hanger side  106  further has an inside face  114  and an outer face  118  and the outboard hanger side  108  similarly has an inside face  116  and an outside face  120 . To reduce the possible deformation of the hanger bracket sides  106  and  108 , it is preferable to install a reinforcement plate  122  on the hanger side outside faces  118  and  120  such that each reinforcement plate  122  is substantially aligned with and adjacent to a lower edge of each outside face  118  and  120 . It is preferable that each side reinforcement plate  122  is formed of hardened steel and welded to outer faces  118  and  120  of hanger bracket sides  106  and  108  respectively. To further strengthen the hanger bracket assembly  102 , it is preferred to fix a torsion plate  164  to the lateral flange  110  and to the inside faces  114  and  116  of hanger bracket sides  106  and  108  respectively. The torsion plate  164  may include clearance holes  166  to allow access to fasteners for securing the mounting plate  104 . 
     A series of bores is provided, in axial alignment, through both hanger bracket sides  106  and  108 . At the uppermost position in the series of bores is a horizontally elongated bush pin bore  124  and a fastener bore  126 . The bush pin bore  124  is horizontally elongated to allow linear movement of a bush pin  128  within the bore  124 , but is sized to restrict vertical movement of the bush pin  128  within the bore  124 . Adjacent to and below the bush pin bore  124 , a fastening bolt access bore  126  is provided through the hanger bracket sides. Each reinforcement plate  122  must be provided with a horizontally elongated pin bore  125  which is similar in dimension to that provided in each bracket side  106  and  108 . 
     A cam, or fore/aft adjustment plate,  130  as shown in FIGS. 2 and 3, is preferably formed of hardened steel and is generally spade-shaped. At least one such cam  130  is positioned outboard each reinforcement plate  122  and is substantially aligned with the series of provided bores  124 ,  126  in the hanger brackets sides  106  and  108  as best shown in FIG.  2 . As shown in FIG. 3 each cam  130  has, in alignment, a spindle bore  132 , a bush pin opening  134 , a square opening  136  and an arcuate-shaped fastening bolt opening  140 . Each cam  130  overlies a reinforcement plate  122  at each outer face  118  and  120  of the hanger bracket sides  106  and  108 , such that the spindle bore  132  of the cam  130  aligns with the spindle hole  138  of the reinforcement plate  122 , the bush pin opening  134  aligns with the horizontally elongated bush pin bores  124  and  125  and the arcuate-shaped fastening bolt opening  140  aligns with the fastening bolt bore  126 . A tang  142  is integrally formed in the cam substantially near the arcuate-shaped fastening bolt opening  140  and oriented in a generally downward position. The tang  142  is preferred to allow visual orientation of the cam relative to the stationary reinforcement plates  122 . The tang  142  may be configured as a generally square projection for grasping with a common spanner or wrench for manipulating the cam  130  laterally with respect to the hanger sides  106  and  108  for the purpose of aligning the control arm bush. The tang  142  can be configured for grasping an manipulating, for alignment purposes, in any size and shape which can be grasped with a tool. 
     Referring again to FIG. 2, each cam  130  is positioned at the outer face  118  and  120  of the hanger bracket sides  106  and  108  respectively. Each provided opening through the cam  130  is aligned with the bores of the adjacent reinforcement plate  122  and hanger sides  106  or  108 . A fastening bolt  144  is positioned through each of the fastening bolt access bores  126  of each the hanger sides  106  and  108 , through the reinforcement plate square opening  146  and through the arcuate-shaped fastening bolt opening  140  of each cam  130 . The preferred fastening bolt  144  is a carriage bolt having a substantially flat head and a square shoulder above common threads. Each fastening bolt bore  146  should be square and sized to accommodate the square shoulder of the fastening bolt. Preferably, the fastening bolt  144  is positioned from within the hanger bracket so that threaded end extends outward through the fastening bolt opening  140  of the cam  130 . Use of the reinforcement plate  122  also allows the fastening bolt head to be recessed into the hanger bracket side to avoid contact between the fastening bolt  144  and the control arm bush  150 . The square shape of the fastening bolt bore  146  will restrict turning of the fastening bolt  144  and allows a mated nut  148  to be installed or removed without removing the bush  150  from the hanger bracket  102 . 
     As shown in FIG. 1, a bush end  152  of a suspension control arm  154 , having a bush pin receiver  156  therethrough, is positioned between the inside face  114  of the inboard hanger side  106  and the inside face  116  of the outboard hanger side  108 , and oriented such that the bush pin receiver  156  is aligned with the bush pin bores  124  formed through both the outboard and inboard hanger bracket sides  106  and  108 . A bush pin  128 , preferably a compression bolt, is secured through the bush pin opening  134  of each cam, the bush pin bores  125  of the reinforcement plates  122 , the elongated bush pin bore  124  of each hanger side  106  and  108  and the bush pin receiver  156  of the control arm bush end  152  and secured with nut  167 . 
     A spindle  158  is rotatably fixed through the spindle hole  132  of the cam  130  and provides a fulcrum point about spindle opening  138  of the reinforcement plate  122  which the cam  130  articulates. As a rotational force is applied about the square opening  136  of the cam  130 , the spindle  158  limits rotation of the cam  130  around the bush pin  128  eliminating any cam twist, which could develop under such force. The spindle  158  may be a round bar affixed to spindle hole  132  of the cam  130  either through interference fit or preferably welded. Alternatively, the spindle  128  may be a rivet, bolt or may be a protrusion pre-formed onto the cam  130 . 
     When the bush pin  128  and the fastening bolt  144  are secured, the bush end  152  of the control arm  154  is fixed into position within the hanger bracket  102 . If the bush pin  128  and the fastening bolt  144  are loosened, each cam  130  can be articulated about the spindle  158 , either within the limitations defined by the arcuate-shaped fastening bolt opening  140  of the cam  130  or by bush pin  128  movement within the horizontal bush pin bore  124  of each hanger bracket side  106  and  108 . It is preferable that a cam  130  be provided at both the inboard and outboard hanger sides  106  and  108 , in alignment to prevent binding, or undesirable stress within the hanger bracket  102 . This can be accomplished by uniform alignment of the tang  142  on each cam  130  relative to the reinforcement plate  122 . 
     Actuation via a breaker bar on the square opening  136  on each cam  130  causes horizontal displacement of the bush pin  128  within the elongated bush pin bore  124 . Horizontal movement of the bush pin  128  allows alignment of the suspension control arm  154  in relation to the vehicle chassis  100 . As the control arm is fixed to the axle  106 , as shown in FIG. 1, any change in relation between the bush end  152  of the control arm  154  within the suspension hanger bracket  102  results in linear forward or rearward movement of the axle  106  with respect to the vehicle chassis  100 . 
     When the desired alignment of the axle  106  is achieved, determined by the control arm bush  150  orientation within the hanger bracket  102 , the bush pin  128  and fastening bolts  144  are tightened. The fastening bolts  144  and bush pin  128  provide two distinct compression points which secures the control arm bush  150  relative to the bracket  102  and greatly reduces the potential for undesired displacement during vehicle operation. 
     When the axle  160  is aligned and the bush pin  128  and fastening bolts  144  are secured, significant clamping pressure should be exerted to maintain control arm bush  150  positioning. The suspension hanger is also provided with an upper shock absorber bracket  162 , preferably on the inboard side  106 , substantially near the mounting plate  104 . 
     Each suspension system requires two opposed hanger brackets positioned on either side of the vehicle chassis. It is understood that the disclosure herein specifically describes a single hanger bracket and the second hanger bracket would be a mirror image of the first. 
     Having specifically described illustrative embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope and spirit of the invention as defined in the appended claims.