Patent Publication Number: US-8979105-B2

Title: Adjustable mounting assembly for vehicle leaf spring

Description:
This is a Continuation-in-Part of U.S. patent application Ser. No. 12/971,901 filed on Dec. 17, 2010, the entirety of the disclosure of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION 
     The present invention relates generally to the vehicle field and, more particularly, to an adjustable spring mounting assembly to retain the end of a leaf spring to the frame of a vehicle as well as to a method of aligning the axle or axles of a vehicle. 
     BACKGROUND OF THE INVENTION 
     Recreational vehicles (RVs) and trailers are relatively common in the art. Many suffer from axle alignment problems. In fact, many RV&#39;s leave the factory in an out of alignment condition. The out of alignment condition may be produced as a result of a number of factors including, but not limited to, unbalanced loading caused by RV floor plan arrangement or slide out placement. Sometimes the frame of the vehicle is wrenched out of square when floors, walls and slide outs are attached. In still other instances the recreational vehicle may suffer from faulty placement of spring hangers and tie plates. Still further, poor quality control of running gear components may cause alignment problems. 
     Even if a recreational vehicle or trailer leaves the factory in proper alignment, misalignment problems may develop later. Such later developing problems may result from, for example, road hazard damage, worn out spring bushings and/or spring fatigue resulting from unbalanced loading. 
     Trailer or axle misalignment is a very undesirable condition with many negative ramifications. Specifically trailer or axle misalignment adversely impacts tire tracking resulting in reduced fuel economy and tire service life. Misalignment can also increase the potential for tire blowouts which are capable of causing a lot of expensive collateral damage to suspension parts, fender skirts, holding tanks, stabilizers and other undercarriage components. Misaligned axles can also lead to tire vibration that causes premature wear to suspension components. The added vibration may also contribute to premature failure of RV contents such as TV&#39;s, satellite gear, refrigerators, microwaves, computers, air conditioning and heating units. Further, vibrations from axle misalignment may also weaken propane and water connections, cabinet mounts and fastener connections throughout the RV thereby reducing the life and effectiveness of fire alarms, CO 2  alarms and electrical systems. 
     The present invention relates to an adjustable spring mounting assembly that may be utilized to correctly align the axle or axles of a recreational vehicle or trailer and thereby eliminate all of the deleterious consequences produced by such a condition. 
     SUMMARY OF THE INVENTION 
     In accordance with the purposes of the present invention as described herein, an adjustable spring mounting assembly is provided. The adjustable spring mounting assembly comprises a first alignment correction plate including a first mounting aperture, a first mounting slot and a first adjustment slot as well as a second alignment correction plate including a second mounting aperture, a second mounting slot and a second adjustment slot. The assembly further includes a spacer that is sandwiched between the first and second alignment correction plates. A first fastener is received in the first and second mounting apertures while a second fastener is received in the first and second mounting slots. Together the first and second fasteners function to mount the assembly to a vehicle spring hanger bracket. A third fastener is received in the first and second adjustment slots. The third fastener functions to connect the assembly to a vehicle spring. 
     More particularly describing the invention, the first alignment correction plate includes a first channel and the second alignment correction plate includes a second channel. A first spacer cam is received in the first channel and a second spacer cam is received in the second channel. The first spacer cam is secured in the first channel and the second spacer cam is secured in the second channel by the third fastener. The first spacer cam comprises a first multi-sided eccentric plate and the second spacer cam comprises a second multi-sided eccentric plate. The first multi-sided eccentric plate includes a first aperture provided in an eccentric position and the second multi-sided eccentric plate includes a second aperture provided in an eccentric position. Still further the first multi-sided eccentric plate includes two sides engaging first sidewalls of the first channel while the second multi-sided eccentric plate includes at least two sides engaging second sidewalls of the second channel. 
     The first alignment correction plate has a first end and a second end. The first mounting slot is provided adjacent the first end while the first alignment slot is provided adjacent the second end. The first mounting aperture is provided between the first mounting slot and the first alignment slot. The second alignment correction plate has a third end and a fourth end. The second mounting slot is provided adjacent the third end while the second alignment slot is provided adjacent the fourth end. The second mounting aperture is provided between the second mounting slot and the second alignment slot. 
     The spacer is a box open on two sides. The first and second fasteners extend through the box. Still further the vehicle spring hanger bracket is captured between the spacer and the first and second alignment correction plates. 
     In accordance with an additional aspect of the present invention, a trailer is provided comprising a trailer frame incorporating at least one adjustable leaf spring mounting assembly as described above. 
     In accordance with still another aspect of the present invention a method is provided for aligning one or more axles on the frame of a vehicle. The method comprises the steps of securing adjustable spring mounting assemblies to the original equipment manufacturer vehicle spring hanger brackets mounted to the vehicle frame, measuring to confirm proper alignment geometry of the one or more axles and adjusting the position of fasteners in the spring mounting assembly so as to secure the one or more axles in proper alignment on the frame. The method may further include the drilling of a mounting hole in each of the original equipment manufacture vehicle spring hanger brackets to which an adjustable spring mounting assembly is to be secured. Where the vehicle is a trailer with a coupler or king pin, the measuring step includes measuring between the coupler or king pin and the one or more axles at the left side of the frame and the right side of the frame. Further, the adjusting step includes manipulating eccentric cams with respect to brackets of the leaf spring mounting assemblies. 
     In the following description there is shown and described several different embodiments of the invention, simply by way of illustration of some of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modification in various, obvious aspects all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings incorporated herein and forming a part of the specification, illustrate several aspects of the present invention and together with the description serve to explain certain principles of the invention. In the drawings: 
         FIG. 1  is an exploded perspective view of the adjustable spring mounting assembly of the present invention; 
         FIG. 2  is a perspective view illustrating the mounting assembly of  FIG. 1  welded to the frame of a trailer and holding a leaf spring; and 
         FIG. 3  is a cross sectional view illustrating the mounting assembly welded to the frame of a trailer and holding a leaf spring as per the illustration in  FIG. 2 ; 
         FIG. 4  is a bottom plan view of a trailer; and 
         FIG. 5  is a plan view of a sixteen sided cam spacer providing for fine adjustments of ⅛ inch (0.3175 cm) in dimension. 
     
    
    
     Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
     Reference is now made to  FIG. 1  illustrating the adjustable leaf spring mounting assembly  10  which is mounted to a vehicle spring hanger bracket  12  secured to the frame F of a vehicle such as a recreational vehicle (RV) or trailer. The assembly  10  comprises a first alignment correction plate  14 , a second alignment correction plate  16  and a spacer  18 . A first fastener  20  and a second fastener  26  function to mount the first and second alignment correction plates  14 ,  16  through the substantially U-shaped vehicle spring hanger bracket  12  that is welded or otherwise secured to the frame F of the vehicle. More specifically, the spacer  18  is positioned between the two legs  25  of the vehicle spring hanger bracket  12 . The first fastener  20 , in the form of a bolt, is then extended through the first mounting aperture  22  in the first alignment correction plate  14 , the first aperture  23  in the first leg  25  of the vehicle spring hanger bracket  12 , the opening in the spacer  18  sandwiched between the legs  25 , the second aperture  23  in the second leg  25  of the vehicle spring hanger bracket  12  and then through the second mounting aperture  24  in the second alignment correction plate  16 . The fastener  20  further includes a cooperating washer and nut  20  to complete the connection. 
     The second fastener  26 , again in the form of a bolt, extends through the first mounting slot  28  in the first alignment correction plate  14 , the apertures  29  in the legs  25  of the vehicle spring hanger bracket  12  as well as the opening in the spacer  18  and the second mounting slot  30  in the second alignment correction plate  16 . The fastener  26  further includes a cooperating washer and nut that completes the connection. 
     The adjustable spring mounting assembly  10  further includes a third fastener  32  that functions to secure the leaf spring S to the adjustable spring mounting assembly  10 . More specifically, the third fastener  32 , in the form of a bolt, extends through a first adjustment slot  34  provided in the first correction plate  14 , the bushing B of the leaf spring S and the second adjustment slot  36  provided in the second alignment correction plate  16 . The fastener  32  also includes a cooperating washer and nut  32  that completes this connection. Optional washers  33  may be provided on the fastener  32  between each side of the bushing B and the correction plates  14 ,  16 . 
     Adjustability is provided by first and second cam spacers  42 ,  44 . More specifically, each of the cam spacers  42 ,  44  is provided in the form of a multi-sided eccentric plate. Eight sided cam spacers  42 ,  44 , illustrated in the drawing  FIGS. 1-3  provide for adjustments of ¼ inch (0.6350 cm) in dimension. It should be appreciated that other configurations are possible and that each spacer  42 ,  44  may include two or more pairs of opposing sides to allow for adjustability. The first cam spacer  42  includes a first fixing aperture  46  while the second cam spacer  44  includes a second fixing aperture  48 . Each of the fixing apertures  46 ,  48  is provided off-center in an eccentric position in each cam spacer  42 ,  44 . 
     As best illustrated in  FIGS. 2 and 3 , the third fastener  32  extends through the first eccentric aperture  46  in the first cam spacer  42  thereby securing the first cam spacer in a first channel  38  of the first alignment correction plate  14 . Similarly, the third fastener  32  passes through the second eccentric aperture  48  in the second cam spacer  44  to secure the second cam spacer in the second channel  40  formed in the second alignment correction plate  16 . 
     The mounting point for the leaf spring S of the trailer axle (not shown) may be adjusted depending upon the orientation of the spacers  42 ,  44 . More specifically, the first channel  38  has a width between the opposing channel side walls  50  that substantially corresponds to the width of the first spacer  42  but includes the necessary clearance to allow the spacer to be received in the channel  38 . Similarly, the second channel  40  has a width between the opposed sidewalls  52  that substantially corresponds to the width of the second spacer  44  but includes the necessary clearance to allow the spacer  44  to be received in the channel  40 . By rotating or manipulating the eccentric cam spacers  42 ,  44 , the position of the third fastener or mounting pin  32  in the aligned elongated adjustment slots  34 ,  36  may be adjusted forward or rearward as desired (that is into and out of the plane of drawing  FIG. 3 ) to properly align the axle or axles of the trailer in accordance with a method that will be described in greater detail below. The elongated slots  34 ,  36  may, for example, allow up to 0.9375 inches of fore/aft adjustment with respect to the vehicle frame F. When properly seated, the opposing sidewalls of the cam spacers  42 ,  44  engage the sidewalls  50 ,  52  of the channels  38 ,  40 . 
     The method of aligning one or more axles on a frame of a vehicle in accordance with the present invention includes the steps of: (a) securing adjustable spring mounting assemblies  10  to the original equipment manufacturer vehicle spring hanger brackets  12  mounted to the vehicle frame F; (b) measuring to confirm proper alignment geometry of the one or more axles; and (c) adjusting position of fasteners  32  in the spring mounting assemblies  10  so as to secure the one or more axles in proper alignment on the frame F. This position adjustment is made using the cam spacers  42 ,  44 . 
     As noted above, each adjustable spring mounting assembly  10  includes two fasteners  20 ,  26  to secure the assembly to the vehicle spring hanger bracket  12 . Significantly the mounting slots  28 ,  30  provided in the first and second alignment correction plates  14 ,  16  accommodate different spacing between the apertures  23 ,  29  in the legs  25  of the vehicle spring hanger bracket thereby allowing mounting of the adjustable spring mounting assembly  10  in existing apertures  23 ,  29  for most applications. It may, however, become necessary to drill an additional mounting hole in each leg  25  of the original equipment manufacturer spring hanger bracket  12  to which an adjustable spring mounted assembly is to be secured. Where the vehicle to which the adjustable spring mounting assembly  10  is to be connected is a trailer with a coupler or king pin, the measuring step includes measuring between the coupler or king pin and the one or more axles on the left side of the frame and on the right side of the frame. In addition, the adjusting step includes the manipulating of the cams  42 ,  44  with respect to the alignment correction plates  14 ,  16  of the leaf spring mounting assembly  10 . 
     Retrofitting of the adjustable spring mounting assembly  10  to the frame F of a vehicle or trailer may be easily performed in the field by completing installation in accordance with the following directions. For purposes of this description, reference is made to  FIG. 4  showing a state-of-the-art trailer T including a frame F, a kingpin or coupler K and an axle A. Of course, the trailer T may include more than one axle. 
     Installation:
         a. Disconnect Battery and LP gas.   b. Level trailer T front-to-back using only the front jacks. Then measure from the center of kingpin or coupler K to each axle U-bolt plate on left and right sides. This can be done using a plumb line to mark a spot on the ground and measuring up to the axle plate.   c. Record these measurements for future use. Some trailers weigh more on different sides, allowing the springs to spread apart, and causing them to become misaligned.   d. Measure from the right front axle plate to the right rear axle plate. Record the measurement. Do the same for the left side.   e. Check measurements for misalignment.   f. Support the trailer with jack stands on all four corners.   g. Block tires on one side of the trailer T.   h. Remove the wheels on the other side. Using jacks to support the axles A, remove the spring bolts from the hangers.   i. It is suggested to replace all the inserts (if you have them) in the springs and the equalizer.       

     Installing Alignment Correction Plates 
     Hanger Preparation:
         a. With bolts removed from hangers  12 , use the jacks to lower the axles A about two inches.   b. Place an alignment correction plate  14  on the outside of one of the hangers  12 . Align the center hole  22  with the bottom hole  23  of the hanger  12 . Place a 9/16×4″ fastening bolt  20  through the plate  14  and hanger  12 .   c. Make sure the sides of the hanger  12  and alignment correction plate  14  are aligned.   d. Clamp the pieces together, making sure not to cover the slot  34  in the plate  14 .   e. Use a ½ inch drill to spot a hole. Go through the ½×1⅝ slotted area  28 , into the hanger  12 . (Try to place the hole as high up as possible without braking into another hole).   f. Use a ¼ drill bit to finish drilling through the spot in the ONE SIDE of the hanger  12 .   g. Do the same on the backside of the hanger. (Steps  2 - 6 )   h. Repeat  2 - 7  on the remaining hangers.   i. Drill open all the ¼ drilled holes to ½ inch. You may step directly up to a ½ inch drill; or if you find it easier, use a ⅜″ bit prior to the ½ finished size.       

     Installation:
         a. Place alignment correction plates  14 ,  16  on the outsides of the spring hanger  12 . (These are the plates with two slots in them, one horizontal and one vertical.) Align the center hole  22 ,  24  with the bottom hole  23  of the hanger  12 . Place a 9/16×4″ bolt  20  through the plate  14 ,  16 , spacer  18 , and hanger  12 . (Use the 3×3×1⅞ spacer in the center of the hanger.) Install a nut on the backside and snug it up.   b. Use a ½×3½ bolt  20  to go through the slot, hanger spacer, and drilled hanger holes. Install a nut on the backside and snug it up.   c. Repeat steps  1  &amp;  2  on the other spring hanger, or hangers.   d. Equalizer/Center Hanger Plates have two holes and one horizontal slot. Install these the same as the Spring Plates.   e. Tighten all installed bolts up to this point.       

     f. Use jacks to raise axle in order to bring the spring eye back into the hanger area.
         g. Start with the equalizer hanger. Place two spring shim washers on either side of the equalizer and between the alignment correction plates. Bolt together, using a 9/16″ bolt and nut. Tighten the nut until there is about 1/16″ of play between the two alignment correction plates and the spring. (The spacers should spin freely on the bolt.)   h. Next start on front spring hanger. Place new spring spacers (welded or not welded) on both sides of the spring and between the alignment correction plates. (You may have to place  3  on one side and  1  on the other to prevent binding.   i. Place a cam spacer  42  over a 9/16″ bolt. The cam should hang down with the hole being in the center, from left to right. Thread the bolt through the plates, shims, and spring. Place a second cam spacer  44  on the back end. Just start the nut so the assembly doesn&#39;t fall apart. (Cam spacers  42 ,  44  are used ONLY on Spring Hangers) Make sure the cams are seated in the channels  38 ,  40  and locked between their side rails  50 ,  52 .   j. Repeat steps  8  &amp;  9  on remaining spring hanger(s).   k. Using the measurements recorded on paper determine how much adjustment is needed on each of the axles A. Each notch of the cam spacers  42 ,  44  when turned equals ¼″ of an inch of adjustment.   l. Make adjustments as needed on each of the spring hangers.   m. Tighten the nuts until there is about 1/16″ of play between the alignment correction plates  14 ,  16  and the spring. (The spacers should spin freely on the bolt.)   n. Verify all nuts and bolts are tightened properly.   o. Reinstall wheels.   p. Repeat instructions for second side of the trailer.       

     Verify Alignment
         a. Level trailer T front to back using on the front jacks. Then measure from the center of kingpin or coupler to each axle U-bolt plate on left and right sides. This can be done using a plumb line to mark a spot on the ground and measuring up to the axle plate. Record these measurements for future use.   b. Measure from the right front axle plate to the right rear axle plate. Record the measurement.   c. Do the same for the left side.   d. Check measurements for misalignment.       

     Aligning Your Axles
         a. Release pressure on cam bolt by jacking up the frame F. Stop just before the tire is lifted off the ground.   b. Remove nut from backside of cam bolt.   c. Tap end of bolt until the cam clears the locking tabs.   d. Rotate cam to get desired movement of axle A. The jack may have to be adjusted up or down in order to get the cam aligned with the locking tabs on the hanger.       

     Numerous benefits result from employing the concepts of the present invention. More particularly, one or more axles A may be properly aligned with the king pin or coupler K of a trailer. Misalignment of axles A can be caused by a number of factors including uneven loading between or across axles. By ensuring alignment of all axles A of a multi-axle trailer T, tire sidewall heating is reduced and tire life is increased. Further vehicle fuel mileage is increased as the drag from misaligned tires is eliminated. In addition, proper multi-axle alignment helps keep the trailer T straight when braking. Further, it should be appreciated that the axles A may be spread slightly to provide more clearance between tires while still ensuring alignment between the axles. In many applications this will allow better trailer weight distribution over the axles A and easier access for inspection and repair of suspension and brake components. 
     Still further, use of the adjustable spring mounting assembly of the present invention effectively raises the frame F two inches with respect to the ground. The resulting increase in the ground clearance of the fifth wheel or travel trailer T aids in coupling the trailer to higher ground clearance towing vehicles such as pick up trucks as well as other vehicles designed for off-road applications. 
     The foregoing description of the preferred embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. For example,  FIG. 5  illustrates an alternative embodiment of eccentric cam spacer  80  which has an off-center fixing aperture  82  and sixteen sides  84 . This cam spacer  80 , having an overall diameter of 2.99 inches (7.5946 cm), provides a fine adjustment in eight graduations, each of ⅛ inch (0.3175 cm) dimension. This allows one to more finely adjust axle alignment of any vehicle. 
     The embodiments were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled. The drawings and preferred embodiments do not and are not intended to limit the ordinary meaning of the claims in their fair and broad interpretation in any way.