Abstract:
The present invention is directed to a replacement steering assembly for a rear steer vehicle and requires no cutting/removal of suspension components or drilling holes or welding of vehicle frame rails. The replacement steering assembly includes a cradle for support a replacement steering system. The cradle includes spaced apart first and second side plates and a center support extending therebetween. A mounting portion of the first side plate includes mounting holes to affix the plate to the left side frame rail and a mounting portion of the second side plate includes mounting holes to affix the plate to the right side frame rail. The first and second side plate mounting holes are configured to align with existing mounting holes in the frame rails which were provided to mount original vehicle steering assembly. The center support is offset vertically downwardly and positioned forwardly of the side plate mounting portions.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a replacement or aftermarket steering assembly and, more particularly, to a replacement steering assembly including a cradle for supporting the replacement steering system wherein the cradle is adapted to be directly bolted to the vehicle&#39;s frame rails without the need for welding or drilling the frame rails or cutting or removal of any vehicle suspension members. 
   BACKGROUND OF THE INVENTION  
   The steering systems on many older vehicles are of antiqued design and have poor performance compared with modern steering systems. Owners of such older vehicles, seeking to improve steering performance, may replace original equipment steering systems, such as steering boxes, with better performing, more reliable systems such as rack and pinion steering systems. 
   When replacing a steering box with a rack and pinion steering system, the vehicle must support the rack and pinion system which typically extends between the vehicle&#39;s outer tie rods and is coupled via a linkage to the vehicle&#39;s steering wheel. A replacement rack and pinion system typically includes pivoting inner tie rods extending from a center housing that encloses the rack and pinion gearing. The rack is disposed inside the housing and is moved along its longitudinal axis by the pinion gear, which is coupled to the vehicle steering system. The inner tie rods of the replacement rack and pinion system thread into outer tie rods of the vehicle steering system such that as the pinion gear is rotated by the steering wheel, the rack moves longitudinally in one direction thereby moving the inner and outer tie rods and turning the vehicle wheels. 
   In body-on-frame vehicles, the vehicle body, engine, drive train, braking, steering and suspensions systems are bolted to the frame. The frame includes frame rails and frame cross members which are welded together, much like a ladder. The frame rails are generally parallel steel channels that extend substantially the length of the vehicle along opposite sides of the vehicle and are generally rectangular in cross section. 
   In unibody vehicles, by contrast, the body and frame are integrated and formed of a single stamping. A unibody vehicle does not have a separate frame, rather the unibody frame includes reinforced support points for mounting the engine, transaxle and other vehicle systems. Specifically, most vehicles with unibody construction include parallel front suspension mounting supports that support the front wheels and the front wheel suspension and steering systems. Some vehicles are a hybrid between unibody construction and body-on-frame construction having a unibody body and a partial or sub-frame that comprises the front suspension mounting supports. As used herein, the term “frame rails” will refer both to the parallel front suspension mounting supports of unibody and hybrid vehicles as well as the forwardly extending frame components that support the front wheels and front suspension systems of body-on-frame vehicles. 
   Using U-bolts to couple the rack and pinion housing to the frame rails is undesirable because the rack and pinion system becomes part of the vehicle suspension system, essentially becoming a cross member that extends between the frame rails. Flexing of the frame rails as the car is driven subjects the rack and pinion housing to stress, stain and shear forces. Since the rack and pinion system is not engineered to be a suspension member, such use typically leads to poor performance and/or premature failure of the rack and pinion steering system. 
   A more sophisticated method of supporting a replacement rack and pinion steering system involves mounting the rack and pinion housing to a support cradle and, in turn, mounting the cradle to one or both of the frame rails. Unfortunately, because vehicles designed with a steering box did not envision mounting of a cradle between the front suspension mounting supports, providing clearance for the rack and pinion system and the cradle supporting it is problematic. Because of clearance considerations, prior art cradles typically required cutting/removal of a suspension cross member to make room for the rack and pinion system and the cradle. Obviously, cutting/removal of a suspension member is a major disadvantage both from a performance perspective and from a vehicle resale position. Many potential purchasers of older, vintage vehicles are willing to pay a premium for vehicles that have not been modified, that is, that are in original condition. Thus, vehicle owners who install a replacement steering system for improved performance often want the option of being able to reinstall the original steering system and return the vehicle to its original condition for resale purposes. 
   Other prior art cradles required either drilling cradle mounting holes into the front suspension mounting supports or welding the cradle to the front suspension mounting supports or a hanger from the mounting supports. Again, this approach has major disadvantages in requiring permanent alteration of the vehicle suspension along with the difficulty and cost attendant with drilling holes in or welding the suspension mounting supports. 
   What is needed is a replacement steering assembly including a support cradle for properly supporting the replacement steering system and isolating it from the forces transmitted through the vehicle suspension system. What is also needed is a replacement steering assembly including a support cradle that does not require any welding, drilling or other permanent alteration of the vehicle upon installation of the cradle. What is also needed is a replacement steering assembly including a support cradle that does not require any cutting/removal of vehicle suspension members. What is also needed is a replacement steering assembly that is easy to install. 
   SUMMARY OF THE INVENTION  
   The present invention is directed to a replacement steering assembly for a rear steer vehicle. A rear steer vehicle in one having the steering system mounted rearwardly with respect to a center line through the front wheels. 
   The replacement steering assembly includes a cradle for supporting a replacement steering system. The cradle includes spaced apart first and second side plates and a center support extending therebetween. A mounting portion of the first side plate includes mounting holes to affix the first side plate to the left side (driver&#39;s side) frame rail and a mounting portion of the second side plate includes mounting holes to affix the second side plate to the right side (passenger&#39;s side) frame rail. The first and second side plate mounting holes are configured to align with existing mounting holes in the frame rails which were provided to mount the original steering assembly. 
   The cradle center support is offset vertically below the side plate mounting portions to provide clearance for the aftermarket steering system from vehicle underbody components including the oil pan, exhaust system and clutch. Extending from the cradle center support are two mounting feet to which the rack and pinion steering system is mounted. 
   In one preferred embodiment of the present invention, the cradle is a rear-loaded cradle. In this embodiment, the mounting feet extend rearwardly (that is, toward the rear of the car) from the cradle center support. Accordingly, the steering system is mounted on the cradle rearwardly of cradle center support. In a second preferred embodiment, the cradle is a front-loaded cradle meaning the mounting feet extend forward of the cradle center support. Accordingly, the steering system, while still being disposed rearwardly of the center line between the tires, is mounted on the cradle forward of the cradle center support. 
   Advantageously, the replacement steering system of the present invention includes a support cradle that properly supports the replacement steering system and isolates it from the forces transmitted through the vehicle suspension system including the vehicle frame rails. The cradle of the present invention does not require any welding, drilling or other permanent alteration of the vehicle. Nor does the cradle require any cutting/removal of vehicle suspension members. Finally, the replacement steering system is easy to install. 
   These and other objects, advantages, and features of the exemplary embodiment of the invention are described in detail in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic top plan view of a front portion of a rear steer vehicle having a replacement steering assembly including a rear-loaded support cradle; 
       FIG. 2  is a front elevation view of the replacement steering assembly of  FIG. 1  as seen from a plane indicated by the line  2 - 2  in  FIG. 1 ; 
       FIG. 3  is an exploded perspective view of the replacement steering assembly of  FIG. 1 ; 
       FIG. 4  is a top plan view of the rear-loaded cradle of  FIG. 1 ; 
       FIG. 5  is a front elevation view of the rear-loaded cradle of  FIG. 1  as seen from a plane indicated by the line  5 - 5  in  FIG. 4 ; 
       FIG. 6  is a left side elevation view of the rear-loaded cradle of  FIG. 1  as seen from a plane indicated by the line  6 - 6  in  FIG. 4 ; 
       FIG. 7  is a right side elevation view of the rear-loaded cradle of  FIG. 1  as seen from a plane indicated by the line  7 - 7  in  FIG. 4 ; 
       FIG. 8  is a top plan view of a front-loaded cradle; 
       FIG. 9  is a front elevation view of the front-loaded cradle of  FIG. 8  as seen from a plane indicated by the line  9 - 9  in  FIG. 8 ; 
       FIG. 10  is a left side elevation view of the front-loaded cradle of  FIG. 8  as seen from a plane indicated by the line  10 - 10  in  FIG. 8 ; and 
       FIG. 11  is a right side elevation view of the front-loaded cradle of  FIG. 8  as seen from a plane indicated by the line  11 - 11  in  FIG. 8 . 
   

   DETAILED DESCRIPTION  
   First Preferred Embodiment—Rear-Loaded Cradle 
   One preferred embodiment of a replacement steering assembly is shown at  100  in  FIGS. 1-3 . The replacement steering assembly  100  includes a manual rack and pinion steering system  110  supported by a cradle or support  150 . Advantageously, the replacement steering assembly  100  may be used to replace the original OEM (original equipment manufacture) steering assembly of a vehicle  10  having a rear steer steering system (often referred as an Omni-type steering system) without the necessity of removing or cutting any vehicle suspension members or otherwise changing the chassis configuration. 
   The replacement steering assembly  100  of the present invention advantageously is a bolt-on system which extends between and bolts directly to the vehicle frame rails  20   a ,  20   b . Moreover, since no cutting of suspension members is necessary and no welding of the cradle  150  to the frame rails  20   a ,  20   b  occurs, the replacement steering assembly  100  may be easily and completely removed if it is desired at any point to reinstall the vehicle OEM steering system. 
   As can best be seen in  FIG. 1 , which shows a front portion the rear steer vehicle  10 , in a rear steer vehicle, the steering assembly  100  is positioned rearwardly (that is, toward the rear of the vehicle) of a center line C-C through the front wheels  12   a ,  12   b . The direction of the front of the vehicle is shown by the arrow F in  FIG. 1 . It should be recognized that rear steer vehicles include body-on-frame vehicles, unibody vehicles and hybrid vehicles having unibody construction coupled to a partial frame. The replacement steering assembly  100  of the present invention will function in any rear steer vehicle provided that cradle is fabricated with proper dimensions to clear the vehicle oil pan, exhaust system and clutch. In a forward portion of the vehicle  10 , the vehicle  10  includes the pair of frame rails  20   a ,  20   b  extending parallel to a longitudinal center line L-L of the vehicle  10 . The frame rails  20   a ,  20   b  support the front wheels  12  and the front wheel suspension system (not shown), as well as the steering assembly  100 . A suspension cross member  40  extends between the frame rails  20   a ,  20   b . The suspension cross member  40  is forward of and parallel to the cradle  150 . 
   The manual rack and pinion steering system  110  includes a generally cylindrical rack and pinion gear housing  112 . The housing  112  includes an aluminum support housing  112   a  and a chrome tube  112   b  extending from the aluminum housing  112   a . The housing  112  encloses and supports the rack and pinion gearing (not shown). The affixed to opposite ends of the housing  112  and extending outwardly therefrom are flexible boots  114   a ,  114   b . Extending outwardly from distal openings in the boots  114   a ,  114   b  are respective threaded inner tie rods  116   a ,  116   b . End portions of the rack and interior end portions of the inner tie rods  116   a ,  116   b  are coupled through respective socket assemblies (which are overlaid and protected from the environment by the flexible boots  114   a ,  114   b ) such that the inner tie rods  116   a ,  116   b  move with the rack but may also pivot 360° with respect to the rack. This pivoting action of the inner tie rods  116   a ,  116   b  with respect to the rack provides necessary movement of the inner tie rods (which must move vertically as the wheels move vertically to negotiate bumps and holes in the road) while protecting the relatively brittle rack and pinion gearing. 
   Exterior threaded end portions  118   a ,  118   b  of the inner tie rods  116   a ,  116   b  thread into threaded openings in vehicle original outer tie rod ends  42   a ,  42   b . The remainder of the steering system  100  from the outer tie rods  42   a ,  42   b  to the vehicle front wheels  12   a ,  12   b  is OEM (original equipment manufacture). While a manual rack and pinion system with a pinion gear offset from the middle of the housing is disclosed, one of skill in the art will recognize that the cradle  150  of the present invention may be used to support various other steering system configurations including center steer rack and pinion systems (wherein the pinion gear centered with respect to the housing) and power assisted rack and pinion systems, among others. The present invention is not limited to a manual rack and pinion steering system with an offset pinion gear. 
   Extending between a steering linkage  130  extends between the vehicle steering wheel  131  and the rack and pinion system  110 . A distal end of the linkage  130  includes a coupling  132  which fits onto a splined shaft  134  ( FIG. 3 ) of the rack and pinion system  110 . The splined shaft  134  is mounted for rotation in bearing (not shown) supported by an angled projection  136  of the aluminum housing  112   a . The splined shaft  134  extends through the housing angled projection  136  is coupled to the pinion gear. As the vehicle steering wheel is turned in one direction, for example, to the left to make a left turn, the pinion gear rotates counterclockwise causing the rack to move axially to the right within the housing  112  and thereby moving the inner tie rods  116   a ,  116   b  to the right. As the inner tie rods  116   a ,  116   b  move to the right, the wheels  12   a ,  12   b  pivot or turn left in a conventional manner. 
   The aluminum support housing  112   a  of the rack and pinion gear housing  112  includes an integral boss  140 . The boss  140  includes a laterally extending mounting projection  142  that defines two mounting openings  142   a ,  142   b  on opposite sides of the housing  112 . A collar  144  is affixed to the housing tube  112   b . The collar  144  also includes a laterally extending mounting projection  146  that defines two mounting openings  146   a ,  146   b , on opposite sides of the housing. 
   The cradle  150 , in addition to supporting the rack and pinion system  110 , effectively isolates the rack and pinion system  110  from many of the forces transmitted through the vehicle suspension system, including the frame rails  20   a ,  20   b  as they flex and twist during normal driving. The cradle  150  includes a center support  152  that extends between a pair of upwardly angled gussets  160   a ,  160   b . The gussets  160   a ,  160   b  extend between the center support  152  and side plates  170   a ,  170   b . Preferably, the cradle  150  is fixture-welded to achieve accurate and uniform tolerances in dimensions and angular relationships between the welded steel components of the cradle components. After fabrication, the cradle  150  is painted preferably using a powder coating painting process. 
   The center support  152  is channel-shaped for added strength and rigidity. The center support preferably is fabricated from 0.1875″-0.25″ thick steel and is 1″×3″ (1″ inch across and 3″ vertical). To provide clearance for the vehicle undercarriage components including the oil pan, the center support  152  is offset vertically below the side plates. Typically, the upper surface  152   a  of the center support  152  is offset 3 inches below a lower edge  172   a ,  172   b  of the side plates  170   a ,  170   b.    
   Affixed by welding to the center support  152  are two mounting feet  154   a ,  154   b  to which the rack and pinion system  110  is affixed to. The mounting feet  154   a ,  154   b  extend under and are welded to a lower surface  152   b  of the center support  152 . For additional strength, the respective mounting feet  154   a ,  154   b  include fluted portions  156   a ,  156   b  that are bent or curved upwardly. An edge  157   a ,  157   b  of each fluted portion extends upwardly along and is welded to a rearward facing surface  154   c  of the center support  152  for improved strength. The mounting feet  154   a ,  154   b  each include a pair of mounting openings or holes  158   a ,  158   b  (preferably 7/16″ diameter). The mounting feet  154   a ,  154   b  support the mounting projections  142 ,  146  of the rack and pinion housing  112 . Steel bolts and lock nuts extends thought the aligned mounting holes of the mounting feet  154   a ,  154   b  and the housing projections  142 ,  145  to secure the rack and pinion system  110  to the cradle  150 . 
   As can be seen in  FIGS. 1-6 , the mounting feet  154   a ,  154   b  extend from the center support  152  toward the rear of the vehicle  10 . Accordingly, the rack and pinion system  110  is loaded or mounted rearwardly of the center support  152 . Hence, the cradle  150  of the first embodiment is referred to as a rear-loaded cradle meaning the rack and pinion system is to the rear of the center support  152 . Also recall that since the vehicle  10  is a rear steer vehicle, the cradle  150  and the rack and pinion system  110  are to the rear of the centerline C-C through the front wheels  12   a - 12   b.    
   The side plates  170   a ,  170   b  include generally planar mounting portions  173   a ,  173   b  that extend in a direction perpendicular to a longitudinal extent the center support  152 , that is, the side plates mounting portions  173   a ,  173   b  are parallel to the longitudinal center line L-L of the vehicle  10  and perpendicular to the cradle center support  152  and the rack and pinion system  110 . Because the side plates mounting portions  173   a ,  173   b  utilize the mounting holes in the frame rails  20   a ,  20   b  formerly used by the steering box and the idler arm, the side plate mounting portions  173   a ,  173   b  must extend rearwardly with respect to the center support  152 . As can best be seen in  FIG. 4 , the center support  152  is offset both vertically below and forward of a general extent to the mounting portions  173   a ,  173   b , that is, forward facing vertical edges  176   a ,  176   b  of the side plates are aligned with a forward facing surface  152   d  of the center support  152 . 
   The cradle  150  extends between and is bolted to respective vertical inward facing surfaces  21   a ,  21   b  of the frame rails  20   a ,  20   b . Specifically, the side plate  170   a  includes apertures or mounting holes  171   a  that match the number and location of the steering box mounting holes  22   a  in the left side frame rail  20   a . For example, in a 1965 Mustang, there were three steering box mounting holes in the left side frame rail. The side plate  170   b  includes apertures or mounting holes  171   b  that match the number and location of the idler arm mounting holes  22   b  in the right side frame rail  20   b . For example, in a 1965 Mustang, there were two idler arm mounting holes in the right side frame rail. 
   Opposite ends  153   a ,  153   b  of the center support  152  are cut at 45° angles. Projections or wings  174   a ,  174   b  extending from the mounting portions  173   a ,  173   b  of the side plates  170   a ,  170   b  are bent to the same angle as the center support ends  153   a ,  153   b  and are welded along the entire perimeter of the ends  153   a ,  153   b  so as to completely cover the ends. To provide extra strength and rigidity to the cradle  150 , the gussets  160   a ,  160   b  extend between the center support  152  and the respective mounting portions  173   a ,  173   b  of the side plates  170   a ,  170   b . The gussets  160   a ,  160   b  are perpendicular to the wings  174   a ,  174   b  resulting in a right-angle bracket connection between the center support  152  and the side plates  170   a ,  170   b . One end of the respective gussets  160   a ,  160   b  is welded to the upper surface  152   a  of the center support  152 . The opposite end of the gussets  160   a ,  160   b  are welded to the respective vertical forward facing edges  176   a ,  176   b  of the side plates  170   a ,  170   b . Preferably, the side plates  170   a ,  170   b  and the gussets  160   a ,  160   b  are fabricated of 0.1875″ steel plate. 
   Installation of Replacement Steering System  100   
   Prior to installing the replacement steering system  100 , the rack and pinion system  110  must be bolted to the cradle  150  to form an integral unit. This is accomplished by positioning the mounting projections  142 ,  146  of the housing  112  on the mounting feet  154   a ,  154   b  such that the openings of the projections are aligned with the openings of the mounting feet. Steel bolts are then inserted through the aligned openings and secured with lock nuts. 
   Additionally, prior to installing the assembled cradle  150  and rack and pinion system  110 , the OEM steering system components (steering box, steering idler arm and inner tie rods) must be removed from the vehicle  10 . 
   The cradle  150  is then affixed to the frame rails  20   a ,  20   b . The cradle  110  is positioned between the frame rails  20   a ,  20   b  such that the apertures  171   a ,  171   b  of the side plates  170   a ,  170   b  are aligned with the corresponding openings in the frame rails  20   a ,  20   b . Suitable steel bolts and lock nuts are used to affix the endplates  170   a ,  170   b  to the frame rails  20   a ,  20   b.    
   Next, the threaded inner tie rods ends  118   a ,  118   b  of the rack and pinion system  110  are threaded into threaded openings formed in the outer tie rod ends  42   a ,  42   b  (which were not removed when the OEM steering system was removed). Finally, the coupling  132  of the steering linkage  130  is affixed to the splined shaft  134  of the rack and pinion system  110  to complete the installation. 
   Second Preferred Embodiment—Front-Loaded Cradle 
   A second preferred embodiment of the cradle of the present invention is shown generally at  250  in  FIGS. 7-11 . In this configuration, instead of the mounting feet extending rearwardly from the center support as was the case in the first embodiment, the mounting feet  254   a ,  254   b  extend forwardly from the center support  252  toward the front of the vehicle  10 . Therefore, the rack and pinion system  110  is loaded or mounted forwardly of the center support  252 . Hence, the cradle  250  of the second embodiment is referred to as a front-loaded cradle meaning the rack and pinion system  150  is to the front of the cradle center support  252 . However, bear in mind that since the vehicle  10  is still a rear steer vehicle, the cradle  250  and the rack and pinion system  110  are both still to the rear of the centerline C-C between the front wheels  12   a ,  12   b . Except for the orientation of the mounting feet  254   a ,  254   b , in all other respects, including the center support  252 , side plates  270   a ,  270   b  and gussets  260   a ,  260   b  are the same as disclosed in the first embodiment and will not be repeated here. 
   Front mounting of the rack and pinion system is advantageous because it provides increased clearance for the vehicle exhaust system located rearward of the cradle center support  252 . Many vehicles with aftermarket header or exhaust systems do not provide sufficient clearance for the rack and pinion system  110  when the rack and pinion system is rear-loaded on the cradle (as shown in the first embodiment). The ability to mount the rack and pinion system  110  on the cradle  250  frontward of the cradle center support  252  increases the number vehicles that may advantageously use the present invention. 
   It is important to note that with respect to both embodiments, specific dimensions of the cradle components and position of mounting holes will be determined by clearance requirements with respect to the vehicle undercarriage including the oil pan, exhaust system and clutch, the location of the mounting holes of the OEM steering system, and the configuration of the replacement/aftermarket steering system  110 , steering linkage requirements, etc., as would be recognized by one of skill in the art. Thus, the cradle configuration will necessarily be modified from what is shown in the drawings for different vehicles models. 
   While the present invention has been described with a degree of particularity, it is the intent that the invention includes all modifications and alterations from the disclosed design falling with the spirit or scope of the appended claims.