Abstract:
A vehicle is provided with an axle suspended from a main frame of the vehicle by right- and left-hand pairs of connecting rods. As viewed from the top, one of each of the right- and left-hand pairs of connecting rods crosses the other of the pair of rods, and, as viewed from the side, the right- and left-hand pairs of rods are disposed parallel to each other. This arrangement of the connecting rods results in the axle moving substantially vertically up and down during operation of vehicle over uneven terrain.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to vehicle suspensions, and more particularly relates to a suspension for a self-propelled agricultural sprayer. 
       BACKGROUND OF THE INVENTION 
       [0002]    One known self-propelled sprayer is provided with a suspension arrangement having each of four drive wheels of the sprayer suspended independently, one each at opposite ends of front and rear axles that are fixed to the main frame of the sprayer. The suspension for each of the wheels includes a large complicated, machined casting fixed to one end of an associated axle and which works together with expensive chrome spindles which telescope within upright sleeves defined by the casting so as to permit relative motion between the wheel and the axle. 
         [0003]    Another known self-propelled sprayer avoids the costs associated with the machined casting and chrome spindles by suspending the axles by the provision of a pair of connecting rods coupled between the vehicle main frame and each of opposite ends of the axle, and by providing a fifth connecting rod that serves as a lateral stabilizer bar. This suspension design suffers from the drawback that the axle swings in an arc about the attachment points of the lateral stabilizer bar creating tracking issues as the suspension goes up and down. 
         [0004]    Accordingly, the problem to be solved is that of providing a wheel suspension for a self-propelled sprayer which overcomes the drawbacks associated with the prior art suspensions. 
       SUMMARY OF THE INVENTION 
       [0005]    According to the present invention, there is provided a vehicle axle suspension including a plurality of connecting rods. 
         [0006]    An object of the invention is to provide a relatively simple vehicle axle suspension including suspension rods arranged in a manner for resulting in the opposite ends of the axle undergoing near vertical up and down motion as the vehicle travels over uneven ground. 
         [0007]    The foregoing object is accomplished by suspending each end of the axle from the vehicle frame by a pair of connecting rods arranged such that as viewed from the side, they are connected in parallel, and as viewed from the top one crosses the other. 
         [0008]    The foregoing and other objects will become apparent from a reading of the ensuing description together with the appended drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a top view of a sprayer vehicle frame with front and rear axles being suspended in accordance with the principles of the present invention. 
           [0010]      FIG. 2  is a left side view of the sprayer vehicle frame and axle suspensions shown in  FIG. 1 . 
           [0011]      FIG. 3  is an enlarged view of a forward region of the vehicle frame and axle suspension shown in  FIG. 2 , but with the wheels removed. 
           [0012]      FIG. 4  is a left front perspective view of the forward region of the vehicle frame and axle suspension shown in  FIG. 3 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0013]    Referring now to  FIGS. 1 and 2 , there is shown a chassis  10  of a high clearance agricultural vehicle, such as a self-propelled agricultural field sprayer, including a main frame  11  supported on a front pair of driven, steerable ground wheels  12  and a rear pair of driven, non-steerable ground wheels  13 . 
         [0014]    The main frame  11  comprises transversely spaced, right- and left-hand, fore-and-aft extending parallel beams  14  and  16 , respectively. The beams  14  and  16  are fixed relative to each other by cross members in the form of front and rear, generally V-shaped: suspension rod mounting brackets  18  and  20 , respectively. The front bracket  18  is spaced to the rear from front ends of the beams  14  and  16  and has opposite vertical ends  22  and  24 , respectively engaged with, and secured, as by bolts (not shown), against outer faces of the beams. The rear bracket  20  is spaced forwardly from rear ends of the beams  14  and  16  and has opposite vertical ends  26  and  28  respectively engaged with, and secured, as by bolts (not shown) against, the outer faces of the beams  14  and  16 . 
         [0015]    Extending beneath each of front and rear end regions of, and disposed crosswise relative to, the parallel beams  14  and  16  are front and rear axles  30  and  32 , respectively. Referring now also to  FIGS. 3 and 4 , it can be seen that the front axle  30  includes a main central section  34  defined by a tube having a square cross section. Joined in depending relationship to opposite ends of the central section  34  are right and left spindle housings, or drop knees  36  and  38 , respectively, which are each inclined upwardly and inwardly at a relatively small angle to vertical. Fixed to, and respectively projecting forwardly from, upper end regions of the drop knees  36  and  38  are right and left steering cylinder mounting arms  40 .and.  42 . Similarly, the rear axle  32  includes a main central section  44  defined by a tube having a square cross section. Joined in depending relationship to opposite ends of the central section  44  are right and left drop knees or spindle housings  46  and  48 , respectively, which are each inclined upwardly and inwardly at a relatively small angle to vertical. 
         [0016]    Right and left hand front spindles (not visible) are respectively mounted for oscillating in the drop knees  36  and  38 . Upper ends of the spindles  50  and  52  project from tops of the drop knees  36  and  38 , and are respectively coupled, as by cap screws  50  and  52 , to right and left steering arms  54  and  56 . Formed integrally with the bottom ends of the spindles are wheel support and motor housings  58  and  60 , with a hydraulic wheel motor  62  being bolted to a mounting surface  64  of each of the housings  58  and  60  and being coupled, in a manner not shown, for driving the front wheels  12 . A right steering cylinder  68  is coupled between the right mounting arm  40  and the right steering arm  54 , while a left steering cylinder  70  is coupled between the left mounting arm  42  and the left steering arm  56 . 
         [0017]    Mounted for oscillating in the drop knees  46  and  48  of the rear axle  32  are right and left rear spindles  72  and  74 , respectively. Formed integrally with a bottom end of the spindles  72  and  74  are right and left wheel support and motor housings  76  and  78 . A hydraulic drive motor  80  is bolted to an outwardly facing mounting surface (not shown) of each of the wheel support and motor housings  76  and  78 , and is coupled for driving an associated one of the non-steerable rear wheels  13 . 
         [0018]    The front and rear axles  30  and  32  are respectively suspended from the main frame  11  by substantially identical front and rear suspension arrangements  84  and  86 , which are mirror images of each other, with only the front suspension arrangement  84  being shown and described in detail for the sake of brevity. 
         [0019]    The front suspension arrangement  84  comprises a middle suspension rod connection bracket joined to, and projecting rearwardly from, an upper central location of the middle section  34  of the front axle  30  and including a pair of right and left, upper suspension rod mounts  88  and  90 , respectively. Located approximately midway between a right end of the axle middle section  34  and the right upper mount  88  is a right, lower suspension rod connection bracket including a right, lower suspension rod mount  92 . Similarly, located approximately midway between a left end of the axle middle section  34  and the left upper mount  90  is a left, lower suspension rod mount  94 . As viewed from the top in  FIG. 1 , the distance between the upper mounts  88  and  90  is substantially equal to the distance between the right upper mount  88  and the right lower mount  92 , and, to the distance between the left upper mount  90  and the left lower mount  94 . 
         [0020]    Joined to and projecting forwardly from a lower middle location of the front suspension rod mounting bracket  18  is a pair of right and left lower suspension rod connection mounts  96  and  98 , respectively. Respectively joined to, and projecting forwardly from, upper right and left end locations of the bracket  18  are an upper pair of suspension rod connection mounts  100  and  102 . As viewed from the top in  FIG. 1 , the spacing between the lower mounts  96  and  98  is substantially equal to the spacing between the right lower mount  96  and the right upper mount  100 , and the spacing between the left lower mount  98  and the left upper mount  102 . 
         [0021]    An upper pair of right and left suspension rods  104  and  106  have forward ends respectively coupled to the upper pair of mounts  88  and  90 , and have rear ends respectively coupled to the upper pair of mounts  100  and  102 . Similarly, a lower pair of right and left suspension rods  108  and  110  have forward ends respectively coupled to the lower right and left suspension rod connection mounts  92  and  94 , and have rear ends respectively coupled to the lower right and left suspension mounts  96  and  98 . 
         [0022]    As viewed from the side in  FIG. 3 , the upper pair of suspension rods  104  and  106  are parallel to the lower pair of suspension rods  108  and  110 . Thus the axle  30  and attached wheels  12  travel substantially vertically during travel over uneven ground. In order to constrain sideways motion of the wheels  12  as they travel up and down, the right set of upper and lower suspension rods  104  and  108 , as viewed from the top in  FIG. 1 , are arranged relative to each other so as to form an X, with the left set of upper and lower suspension rods  106  and  110  being arranged in a similar fashion. 
         [0023]    Up and down motion of the front axle  30  is cushioned by right and left airbags  112  and  114 , having upper ends respectively coupled to right and left horizontal mounting plates  116  and  118  respectively fixed to and projecting outwardly from forward end regions of outer faces of the right and left beams  14  and  16 ; and having lower ends respectively coupled to right and left airbag connection by left and right airbag connection brackets (only left hand bracket  122  is visible) respectively projecting upwardly from right and left end regions of the central section  34  of the front axle  30 . Further cushioning of up and down movement of the axle  30  is provided in conjunction with that afforded by the airbags  112  and  114  by right and left shock absorbers  124  and  126  having respective upper ends coupled to right and left upper mounts  128  and  130 , respectively fixed to and projecting outwardly from the beams  14  and  16  at locations just forward of the airbag mounting plates  116  and  118 , and having respective lower ends coupled to right and left lower mounts (only the right mount  132  is visible) respectively fixed to lower front locations, of the central axle section  34 , which are in approximate vertical alignment with the upper mounts  128  and  130 . 
         [0024]    Up and down motion of the rear axle  32  is similarly cushioned by right and left rear airbags and right and left rear shock absorbers, with the drawings having only a clear showing of a left airbag  134  and a left shock absorber  136  (see  FIG. 2 ). 
         [0025]    It will be appreciated then that the suspended front and rear axles  30  and  32  permit vertical movement of the axles making it unnecessary to provide expensive chrome spindles as are needed with the fixed axle design disclosed in the aforementioned U.S. Pat. No. 7,168,717. Further, it will be appreciated that by arranging the side-by-side sets of upper and lower suspension bars so that they each form an X, as viewed from the top, a substantially straight line or vertical up and down movement of the axle occurs which eliminates the arc motion generated from lateral stabilizer bars used in prior art suspensions, thus eliminating tracking issues that occur when the axle swings in ah arc about the attachment points of the lateral stabilizer bar. 
         [0026]    While two pair of upper and lower suspension rods are used for each axle, it is noted that for some applications a single pair might provide an adequate axle suspension. 
         [0027]    Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.