Patent Publication Number: US-2007102854-A1

Title: Stabilizer for leaf spring suspension device

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates generally to vehicle spring suspensions, and, more particularly, to an improved leaf spring suspension device suitable for attachment to vehicle rear suspension springs.  
      2. Related Art  
      It is the usual practice to isolate the rear axle of a vehicle from the frame of the vehicle by supporting the axle in a multi-leaf type spring which is suspended between a forward bearing bracket and a rearward spring shackle whereby most imperfections in the road surface can be absorbed by the wheel and the spring construction and not be transmitted to the vehicle passenger compartment through the frame. The multi-leaf type of spring is characterized by a plurality of stacked leafs, usually four or five in number, which decrease in length away from the base or mounting leaf in the form of a truncated triangular configuration. The axle suspension connects to the thickest or highest part of the multi-leaf spring to achieve maximum support.  
      Occasionally, when a vehicle is utilized to carry especially heavy loads, the existing leaf springs have a tendency to sag or flex sufficiently to wrap-up or permit “bottoming.” Also, upon unusual wear or unusual surface conditions, the existing springs could allow “forward pitch” or “nose dive” of the vehicle, all to the discomfort of the passengers.  
      In order to enhance the load bearing capabilities of light pickups, trucks, or the like, prior art stabilizing devices have been proposed. Such prior art devices are either made up of a large number of parts, do not adapt easily to preexisting structure or are not totally effective in compensating for heavy loads on the vehicle&#39;s suspension system.  
      In my U.S. Pat. No. 5,992,831, issued Nov. 30, 1999, I disclose a stabilizer for a leaf spring suspension device. U-bolts are used to secure the stabilizing members to the preexisting vehicle multi-leaf member suspension device. Keepers are used on such leaf spring suspension devices to hold the leaves of the multi-leaf spring member. Such U-bolts must not interfere with the keepers holding the multi-leaves together.  
      In my U.S. Pat. No. 6,158,723, I disclose a U-bolt which can be used to hold a stabilizing spring to the preexisting multi-leaf spring member suspension system of a vehicle without interfering with the keepers retaining the multi-leaves of the multi-leaf spring suspension together.  
      However, there is a need for taking up the slack and filling in the space between the bottom of the No. 1 leaf spring in these patents and the top of the No. 1 O.E.M. leaf spring. Such a device should be usable with the preexisting U-bolts of such assemblies. By taking up such slack, compression tension is applied to the spring leaves as they contact. This acts as a spreader keeping this group of mounting hardware constantly in tension while preventing rattling and squeaking.  
     SUMMARY OF THE INVENTION  
      It is an object of this invention to provide a leaf spring suspension device that can be quickly and easily mounted to the preexisting leaf spring suspension of a vehicle which provides compression tension to the spring leaves as they contact.  
      It is a further object of this invention to provide such an improved leaf spring suspension device which has a relatively low number of parts.  
      It is another object of this invention to provide a soft controlled ride when a vehicle is not loaded and is provided with the suspension device of the invention while preventing rattling and squeaking of parts.  
      It is a further object of this invention to carrying out the foregoing objects by maintaining the mounting hardware of the leaf spring suspension constantly in tension.  
      It is still another object of this invention to provide an improved leaf spring suspension system which enhances the roll stability of the vehicle.  
      These and other objects are preferably accomplished by providing an improved leaf spring suspension system for a vehicle having spacers between the bottom of the No. 1 leaf spring of the improved leaf spring suspension system and the top of the O.E.M. No. 1 leaf spring of the vehicle. Such spacers apply compression tension to the spring leaves as they contact thus acting as a spreader to keep the mounting hardware constantly in tension and preventing rattling and squeaking of the parts. Such an improvement enhances the roll stability of the vehicle on which the suspension system is mounted. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a conventional multi-leaf type spring having a leaf spring suspension device mounted thereto in accordance with the teachings of the invention;  
       FIG. 2  is a perspective view of a portion of the assembly of  FIG. 1 ; and  
       FIG. 3  is a prior art illustration of a portion of a conventional leaf spring prior to mounting the device of the invention thereon. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring now to  FIG. 1  of the drawing, a conventional O.E.M. leaf spring assembly  10  is shown having, extending along a longitudinal direction, an elongated spring member  11  fixed to the vehicle frame (not shown) by means of coiled ends  12 ,  13  coupled to suitable brackets (not shown) on the vehicle frame. Leaf spring  10 , as is well known in the art, is comprised of varying lengths of spring members, such as spring members  14 ,  15 ,  16  which are secured to spring member  11  by suitable U-shaped brackets  17 ,  18  which encircle the vehicle&#39;s rear axle  171  as is well known in the art.  
      Brackets  17 ,  18  each have interconnected spaced legs  172 ,  173  extending through holes  175  in mounting bracket  176 . The terminal ends of legs  172 ,  173  are threaded receiving thereon threaded nuts  177 ,  178 , respectively. If desired, spring members  11 ,  14 ,  15 ,  16  may be further secured together at generally the middle thereof by a nut and bolt combination (under bracket  176 —not shown).  
      The foregoing has described original equipment found on vehicles having leaf spring suspension systems. In my U.S. Pat. Nos. 5,922,831 and 6,158,723, the teachings of which are incorporated herein, I described a leaf spring suspension device adapted to be mounted to such a preexisting multi-leaf spring suspension system. Such a system includes, as shown in  FIG. 1 , a leaf spring suspension device  19  having a spring  29  in the form of an elongated curved length of spring alloy steel or the like bent at opposite ends  20 ,  21  to provide a gripping portion in which conventional U-shaped threaded bolts  22 ,  23 , respectively, may be disposed. The spaced legs of each bolt  22 ,  23  are receivable in suitable apertures in brackets  24 ,  25 , respectively, and retained thereto by nuts  26 ,  26 ′ threaded to the threaded ends of bolts  22 ,  23 .  
      Suspension device  19  also includes a curved elongated spring member  27  disposed between spring  29  and multi-leaf spring assembly  10 . Although only one such member  27  is shown, obviously more than one may be provided, such as the 2 such spring members  27 ,  28  in my U.S. Pat. Nos. 5,992,831 and 6,158,723.  
      Member  27  is of a length less than that of spring  29  which is of a unitary length of a leaf of metallic spring material.  
      Leaf spring suspension device  19  further includes each member  27 ,  29  being curved at the middle to form a U-shaped raised portion above the preexisting spring member  11 . Members  27 ,  29  have ends which curve away from member  11  and a pair of threaded U-bolts or brackets  33 ,  34 , couple all members  29 ,  27 ,  11 ,  15 ,  14  and  16  together. The threaded legs thereof extend through aligned holes  35 ′ in spaced plates  35 ,  36  and are secured thereto by nuts  37 ,  37 ′. Thus, U-bolts  33 ,  34 , and plates  35 ,  36  provide bracket means for securing the springs together. Curved member or spring  27  abuts against spring  29  and is slightly less in overall length.  
      The assembly of parts in  FIG. 1  eliminates a number of parts in prior art devices as discussed in my prior patents.  
      As particularly contemplated in the present invention, and shown more particularly in  FIG. 2 , a spacer assembly  100  is provided between leaf spring  29  and leaf spring  11 . This area is shown in the Prior Art view in  FIG. 3  which is a portion of the assembly shown in my U.S. Pat. No. 5,992,831. Here, the upper leaf spring  29  of my prior patent is shown spaced from the O.E.M. leaf spring  11  of the vehicle (not shown). In this view, bracket  23  secures curved end  21  of spring  29  to leaf springs  11  and  15  via bracket  25  and nuts  26 . A space is normally present between the bottom of the groove of curved end  21  and the upper surface of spring  11 .  
      Spacer assembly  100  ( FIG. 2 ) fills this space and includes a central main body portion  101  having outwardly extending spaced ends  102 ,  103  of lesser width then body part  101 . A pair of throughbores  104 ,  105  extend through ends  102 ,  103 , respectively. A large central opening  106  is provided through main body portion  101  having its central axis generally aligned with the elongated axis of spring member  11 . As seen in  FIG. 2 , the spaced legs of bracket  23  extends through holes  104 ,  105 , as shown.  
      Spacer assembly  100  thus abuts at top against the underside  107  of the groove in curved end  21  of leaf spring  29  and the upper surface  108  of spring  11 . Spacer assemblies  100  are provided on each side of the assembly as seen in  FIG. 1 .  
      Thus, the spacer assemblies take up the slack between spring  29  and  11  and fill the space between the bottom or underside  107  of the groove in curved end  21  of leaf spring  29  and the top surface  108  of the O.E.M. leaf spring  11 . The spacer assemblies  100  are retained in position using the existing nuts, brackets, bolts, etc. of such leaf spring kits.  
      Although the spacer assemblies can be of any suitable material, one piece polyurethane is preferred. The spacer assemblies  100  apply compression tension to the spring leaves as they contact. The spacer assemblies act as spreaders to keep the mounting hardware constantly in tension and prevent rattling and squeaking. Such spacer assemblies enhance the roll stability of the vehicle by bringing into play the non-O.E.M. springs opposing tension spring rate.  
      Although a specific embodiment of the invention is disclosed, variations thereof may occur to an artisan and the scope of the invention should only be limited by the scope of the appended claims.