Abstract:
This invention generally relates to devices for an air ride suspension system for one or two axle light duty trailers. More specifically, this invention relates a novel air ride suspension system for light duty trailers that eliminates the need for leaf springs, dissipates normal road vibrations, dramatically reduces the stress on trailers and their fixtures and can be sold and installed in kit form for either above or below axle mounting.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of Provisional Patent Application Ser. No. 60/445,668 filed Feb. 6, 2003. 

   BACKGROUND 
   1. Field of Invention 
   This invention generally relates to devices for an air ride suspension system for a light duty trailer. More specifically, this invention relates a novel air ride suspension system for light duty trailers that eliminates the need for leaf springs, dissipates normal road vibrations, dramatically reduces the stress on trailers and their fixtures and can be sold and installed in kit form for either one or two axle trailers with optional mounting above or below the axle. 
   2. Prior Art 
   A variety of air ride assist suspension systems exist but most of them have the air springs attached to leaf springs. None of the prior art devices disclose the unique features of the air suspension system such as the ability to install in kit form without welding. 
   U.S. Pat. No. 5,865,452 (1999), U.S. Pat. No. 6,182,984 (2001) and U.S. Pat. No. 6,398,239 (2002) all to Chalin are focused on steerable suspension systems. U.S. Pat. No. 5,346,247—Snyder (1994), U.S. Pat. No. 5,470,096—Baxter (1995), U.S. Pat. No. 5,634,655—Chalin (1997), U.S. Pat. No. 5,678,845—Stuart (1997), U.S. Pat. No. 6,328,324—Fenton (2001) and U.S. Pat. No. 6,454,283—Fenton (2002) all disclose various combinations of air springs mounted onto leaf springs. U.S. Pat. No. 6,209,895—Mueller (2001) shows an axle suspension system for a single axle trailer with a forward pivotal mounting arm with a shock absorber mounted in front of the axle and an air spring mounted behind the axle. This patent appears to embody many of the same features as the earlier filed U.S. Pat. No. 4,415,179—Marinelli (1983) with the exception of its Y-shaped stabilizer bar. U.S. Pat. No. 4,714,269—Raidel (1987) again shows an axle mounted suspension system for a single axle trailer but it includes a shock absorber and an air spring before and after the axle and mounted as far out board as possible. 
   SUMMARY 
   In accordance with the present invention, an air ride suspension system is comprised of two angle iron frame rails positioned parallel to each other and open to the inside and top such that the box of trailer can be slipped between the outside walls and sit on the lower walls and are bolted to the trailer box. The frames have control arm brackets, axle stop brackets, air spring brackets, and shock absorber brackets welded to the under side directly opposite of the like bracket on the opposing frame. One set of these brackets on each frame is required for a single axle trailer. Two sets of these brackets are required for a dual axle trailer. Control arms are inserted with resilient bushings and pivotally attached to the control arm brackets at the resilient bushings. Polyurethane stops are screwed into the axle stop brackets. Air springs are mounted onto the control arm behind the axle and attached to the underside of the air spring bracket. Behind the air spring, a shock absorber is mounted to the end of the control arm and connected to the underside of the shock absorber bracket. Axles are mounted either above or below the control arms utilizing standard U bolt mechanisms. This system can be sold in pre-assembled kit form and the kit installed by simply removing the old suspension system from existing trailer, sitting the trailer into the angle iron frame and bolting in place, connecting cross braces between the bottom mounting lug of one control arm bracket and the top mounting lug on the opposing control arm bracket, mounting the old axles onto the control arms, reinstalling wheels and adjusting air spring pressure. 

   
     DRAWINGS 
     In order that the invention may be more fully understood it will now be described by way of example, with reference to the accompanying drawings in which: 
       FIG. 1  is a side elevational view of an air ride suspension system. 
       FIG. 2  is a front end view of the air ride suspension system in  FIG. 1 . 
       FIG. 3  is an enlarged view of the partial section in  FIG. 2  with an exploded section showing the mounting bolt and nut. 
       FIG. 4  is a perspective view of a control arm welded assembly for under axle mounting. 
       FIG. 5  is a cross-sectional view showing axle mounting. 
       FIG. 6  is a cross-sectional view showing air spring mounting. 
       FIG. 7  is a partial side elevational view of an over axle mounting embodiment. 
       FIG. 8  is a perspective view of a control arm welded assembly for over axle mounting. 
       FIG. 9  is a forward facing partial section view showing mounting notch in control arm bracket. 
   

   REFERENCE NUMERALS 
   
     
       
             
             
           
         
             
                 
             
           
           
             
               10 angle iron frame rail 
               12 control arm bracket under axle 
             
             
               14 air spring mounting bracket 
               16 air spring 
             
             
               18 shock absorber 
               20 axle mount ubolt 
             
             
               22 control arm under axle 
               24 cross brace 
             
             
               26 pivot bolt 
               28 cross drill for lube fitting 
             
             
               30 Pivot bolt lock nut 
               32 resilient bushing 
             
             
               34 standard trailer axle 
               36 control arm bracket over axle 
             
             
               38 control arm over axle 
               40 air spring fill valve stem 
             
             
               42 air spring mounting 
               44 u-bolt axle mounting holes 
             
             
                 bracket over axle 
               48 axle centering hole 
             
             
               46 air spring mounting holes 
               52 axle stop 
             
             
               50 axle stop bracket 
               56 mounting holes 
             
             
               54 shock absorber bracket 
               60 control arm bracket trailing side 
             
             
               58 frame rail front end 
               64 tabs 
             
             
               62 1½ in. diameter opening 
               66 leading edge of box frame 
             
             
               68 control notch 
             
             
                 
             
           
        
       
     
   
   DESCRIPTION 
   In order that the invention may be more fully understood, it will now be described by way of example with reference to the accompanying drawings in which  FIGS. 1 through 6  and  9  illustrate an air ride suspension system for light duty travel trailers that have axle or axles  34  mounted to the top of control arm assemblies  22 . 
   Turning to  FIG. 1 ,  FIG. 5  and  FIG. 6 , a right side view and two cross section views respectively of the air ride suspension system shows frame rail  10  which is a frame of 3 in.×3 in.×¼ in. angle iron, open to the top for receiving a box of said trailer (not part of this invention) of a length to fit the underside of a particular trailer with leading edge  66 . Welded to the under sides of frame rail  10  are control arm brackets  12  made from 3 in.×5 in.×¼ in. wall steel tubing, axle stop brackets  50  made from 2 in. diameter sold steel rod, air spring mounting brackets  14  made from 2 in diameter×¼ in. wall tubing with a 5 in. diameter×¼ in. thick plate welded to the bottom of the tube concentric with the tube diameter. 
   Trailing side  60  of control arm bracket  10  has notch  68  which allows insertion of control arm  22 , shown in  FIGS. 4 and 9 , with two resilient bushings  32  inserted into the 1½ in. diameter opening  62  in the end of control arm  22 . A one inch diameter pivot bolt  26 , shown in  FIG. 3 , is then inserted through the clearance hole in the 5 in. wide side wall of control arm bracket  12 , through the two bushings  32  and out the other clearance hole in the back side of control arm bracket  12 . Lock nut  30  is then tightened onto bolt  26  which has crossed drilled and counter bored hole  28  for a lube fitting (not shown). On the opposite end of control arm  22  is a clearance notch and mounting holes  56  for the pivotal attachment of one end of standard shock absorber  18  which is connected at the opposite end pivotally to shock absorber bracket  54 . 
   Axle stop bracket  50  is made from a 2 in. diameter by 2 in. long section of steel rod with a tapped hole centered in one end concentric with the O.D. for screwing in the threaded projection (not shown) from the top of polyurethane axle stop  52 . 
     FIG. 2  is a front end view looking back toward the trailer showing two frames  10  with control arm brackets  12  welded at parallel positions on the opposing frames  10 , aligning the 3 in. side of bracket  12  with the 3 in. width of angle iron frame  10  for a single axle trailer or two sets of opposing control arm brackets for a dual axle trailer spaced as far apart as the axles. Tabs  64  are welded to the top and bottom of the inside, forward edge of control arm brackets  12  for bolting in place cross braces  24  to stabilize the control arm brackets  12 . Increased bearing length for the control arm pivot is obtained by welding 1½ in. O.D.×1 in. I.D.×½ in. thick washers to the outsides of control arm brackets  12  concentric with the 1 in. diameter pivot mounting holes in the 5 in. width of control arm bracket  12 . 
     FIG. 3  is an enlarged exploded view of a partial section of control arm bracket  12  which shows in cross section the 2 in. diameter section of the end of control arm  22  containing two inserted bushings  32  slipped between the 2½ in. internal width of the control arm bracket. In the exploded segment of  FIG. 3 , one inch diameter bolt  26  is shown in line with the clearance holes in the 5 in. sides of the control arm bracket and the I.D.s of bushings  32  and lock nut  30 . Also in  FIG. 3  a small diameter hole, cross drill and counter bore  28  is noted through bolt  26  for a lube fitting (not shown). 
     FIG. 4  is a perspective view showing control arm  22 . Control arm  22  is made from 2 in.×2 in.×¼ in. steel tubing and is notched, bent and welded at a sufficient angle down from the center of bushings  32  to allow the lower section to be displaced approximately level with the ground in its unflexed state. A 2 in. O.D.×1½ in. I.D.×2 in. long steel tube is welded at a right angle to the end of the 2 in. square tube. Two resilient bushings  32  made from series 2000 polyurethane by Daystar, Inc. in Phoenix Ariz., are inserted into its opposing ends. A 11 in.×4½ in.×¼ in steel plate is welded onto the top of the 2×2 steel tube on the lower level section. This plate has 4 holes  44  for the u-bolts  20  for mounting axle  34  to control arm  22 . This plate also has two holes  46  for mounting the bottom of air spring  16  to control arm  22 . Hole  48  is used for the centering dowel that squares the axle to the frame when the u-bolts are tightened. 
     FIG. 5  is a partial section view of  FIG. 1  that shows control arm bracket  12  welded to angle iron frame  10  and two u-bolts  20  holding axle  34  on top of control arm  22 . 
     FIG. 6  is a partial section view of  FIG. 1  that shows air spring  16  being mounted between control arm  22  and air spring bracket  14  which is made from 2 in diameter×¼ in. wall tubing with a 5 in. diameter×¼ in. thick plate welded to the bottom of the tube concentric with the tube diameter which is welded to the under side of angle iron frame  10 . 
   Turning to  FIG. 7 , a partial side view is shown of a second embodiment for trailers which due to the shape and curvature of their axles cannot utilize the design shown above. For these trailers an under control arm axle mount is desired. Again two frames  10  are utilized to assemble the suspension system in kit form for ease of installation. In order to maintain the correct ride height, approximately 5½ inches, the pivot point for control arm  38  is slightly higher in control arm bracket  36  than in control bracket  12 . The first section of 2×2×¼ steel tube of control arm  38 , as shown in  FIG. 8 , is welded to the top of the axle and air spring mounting plate. This plate is not a flat plate as in the earlier embodiment but has a right angle “Z” form to a lower level at sufficient depth to allow control arm  38  to set approximately level with the ground in its unflexed state. Below the bottom section of this plate is welded the lower section of 2×2×¼ steel tube with a similar notch and mounting for standard shock absorber  18 . The horizontal spacing of the mounting holes  44 ,  48 , &amp;  46  are the same as in the earlier embodiment. As shown in  FIG. 7 , two u-bolts  20  are mounted from the bottom side of each control arm  38  on both sides of the 2 in. tube section, thus providing clamping of axle  34  to the under side of control arm  38  and clearance for axles that are curved in shape. Finally,  FIG. 9  is a forward facing partial section view showing control mounting notch  68  in control arm bracket trailing side  60  with control arm  22  pivotally mounted in its center on bushings  32 . 
   The preceding descriptions are for illustrative purposes and are not intended to limit the scope of this invention. The scope of the invention should be determined by the appended claims rather than by the specific examples given. Manufacture and assembly techniques well known to those skilled in the arts of mass production are contemplated on this invention for high volume applications. The embodiments shown are those embraced for start-up volumes but do not limit or constrain this no leaf spring, non-welding installation kit form of air ride suspension system.