Abstract:
A large round baler includes a pair of ground wheels carried at opposite ends of an axle which is suspended from the frame of the baler by a pair of parallel, transversely spaced arms having first ends secured to the axle, and having second ends coupled to the frame by a self-aligning bearing assembly.

Description:
FIELD OF THE INVENTION 
     The present invention concerns the suspension of an axle of a towed agricultural utility vehicle or implement. 
     BACKGROUND OF THE INVENTION 
     From DE-A-197 25 699, a large round baler is disclosed whose wheels engage the ends of an axle, free to rotate, where the axle is connected on each side by means of a leaf spring configured as an arm connected to the frame of the baler so as to pivot vertically against the resistance of a damper element at the opposite end of the spring from the pivot connection of the leaf spring to the frame. The pivot connection of the leaf spring to the frame is formed by an eye on the leaf spring and a pin. The springs are used simultaneously for preventing movement in the sideways direction of the axle and of the wheels. 
     The problem underlying the invention is seen in the fact that on the basis of the varying conditions of the ground, the wheels on each side are accelerated at different rates and the springs are deflected to differing degrees, so that the axle does not always remain parallel to the pivot axis that extends through the bearings and thereby applies loads to the bearings. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided an improved suspension for an axle assembly. 
     An object of the invention is to provide a suspended axle assembly constructed so as to eliminate loading to the bearings mounting spaced arms of the assembly to a vehicle frame. 
     A more specific object of the invention is to provide spherical or self-aligning bearings for mounting the arms, which are fixed to the ground wheel axle, to the vehicle frame. 
     Another object in accordance with a second embodiment of the invention is to provide bearings embodying resilient members which deflect so as to avoid undue loading of the bearings. 
     These and other objects will become apparent from a reading of the ensuing description together with the appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic left side elevational view of a large round baler equipped with an axle suspended in accordance with the principles of the present invention. 
     FIG. 2 is a left rear perspective view of the axle and its suspension. 
     FIG. 3 is a perspective view of one of the arms of the suspension, with a portion broken away and sectioned to reveal the spherical bearing ball chamber. 
     FIG. 4 is a left rear perspective view showing the baler frame and the suspended axle assembly. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, there is shown an implement or vehicle  10  shown generally in the form of a large round baler of a known configuration, including a baling chamber housing  12 , frame  14  and support wheels  16  and that can be equipped as a fixed chamber baler or as one with a baling chamber of variable size. A tongue or tow bar  18  is fixed to the front of the frame  14  for attachment to a tractor so as to be towed across a field. When the implement  10  is towed across a field whose surface is uneven and rough, the baling chamber housing  12  and frame  14  are caused to bounce. In operation on paths and roads, it behaves similarly, since there greater speeds are reached. The configuration as a large round baler is a preferred application for the invention, that is described below, since such balers are being operated with increasing speed on the field and on the roads and carry increasing weight, in the form of a loaded cylindrical bale, that could lead to damage in case of bumps due to uneven terrain. However, other towed agricultural implements that could use the invention with advantage include a forage harvester, a mowing implement, a haymaking machine, a hay recovery machine, a sowing or planting machine or the like. 
     The baling chamber housing  12  is composed of a front part  22 , fixed to and forming part of the frame  14 , and a rear part  24  connected to an upper rear location of the front part  22  for pivoting vertically in a known manner (not shown). In the baling chamber housing  12  a multitude of baling elements, not shown, are provided, such as baling rolls, by means of which a cylindrical bale can be produced. 
     The frame  14  carries the parts  22  and  24  of the baling chamber  12  and is connected in front with the tow bar  18 , where the connection is made rigidly with seam welds, screws and/or rivets. In the lower region of the frame  14 , a connection is provided on each side for the suspension  20 , each of which is configured as a recess, that is not visible. 
     The wheels  16  engage opposite ends of an axle  28 , free to rotate, and support the frame  14  on the ground. The wheels  16  are mounted to wheel hubs  30  which, in turn, are equipped with braking arrangements  32 . 
     The tow bar  18  is used to connect the vehicle  10  to a towing vehicle, not shown, for example, an agricultural tractor. 
     The suspension  20  of the wheels  16  includes a U-shaped assembly defined by the axle  28  and an arm  34  on each end of the axle  28 , and, associated with each arm  34  is a spherical bearing  36 . The suspension  20  is used to connect the wheels  16  with the frame  14  of the vehicle  10 . In this special embodiment, a further axle  38  forms part of the frame  14  and the arms  34  are respectively connected to the opposite ends of the axle  38 . While the bearings  36  could also be attached directly to the frame  14  without using the axle  38 , it appears more advantageous for the sake of the pattern of forces and for stability to provide them on the axle  38  that is rigid in itself, that can be fastened to the frame  14 , for example by means of flanges or by a welded connection. 
     The axle  28  is configured in the form of a tube with a square or rectangular cross section, that extends the entire width of the baling chamber housing  12  and beyond the arms  34 . This axle  28  in itself could also be used in the same way on another agricultural vehicle without the suspension  20  according to the invention. The wheel hubs  30  include brake drums forming parts of the braking arrangements  32  and are supported in bearings, free to rotate, on the ends of the axle  28 . 
     Each arm  34  is configured according to the illustration in FIG.  3  and has an elongated shape. In general, the arm  34  consists of a rectangular tube  40  standing on edge in the assembly that carries a flange  42  on its rear end region, the right end region in FIG. 3, and on its forward end region carries the spherical bearing  36  and is provided with a bore, not visible, through which the further axle  38  can extend. The arm  34  is configured generally as a weldment that establishes the connection between the frame  14  and the axle  28  and is arranged outside the frame  14 . Connected to the flange  42 , or even as a one-piece component with it, a cover flange  46  and a bottom flange  48  are provided, which extend parallel to each other and are equipped with bores, not described in any further detail. Preferably, the flange  42 , the cover flange  46  and the bottom flange  48  are welded to the rectangular tube  40 . 
     The spherical bearing  36  contains a large ball segment  50  with a bore  52  extending axially through it and flattened end surfaces. This ball segment  50  is supported, free to pivot, in a congruent ball chamber  53 , in a manner known in itself, in the arm  34  and is secured by means of a fixed disk  54  and a removable disk  56  against falling out of the ball chamber. Spacer means, not shown, can be provided under the removable disk  56  (FIG. 2) that make it possible to adjust the play of the ball  50  in the ball chamber. The removable disk  56  is secured with several screws  58  on each of the outer sides of the arm  34 . The ball  50  is contained in the ball chamber, so as to be easily movable and permits movements of the arms  34  in the upward direction and to the side within the possible limits. The spherical bearing  36  can be lubricated if this should become necessary, where in this case seals would have to be provided between the ball chamber and the disks  54  and  56 . 
     The further axle  38  is configured as a simple tube that is wider than the frame  14  and is inserted through cylindrical openings, not described in any further detail, in the frame  14  in order to extend beyond these. In the region of contact of the further axle  38  with the frame  14 , these are welded to each other. In principle, the further axle  38  could be replaced by stub axles that are connected to each side. However, the one-piece further axle  38  has the advantage that it reinforces the frame  14  itself. The further axle  38  is dimensioned in such a way that it engages the ball  50  with little play or rigidly on its end regions. The further axle  38  is retained axially against the ball  50  on each side by means of a cover  60 . 
     It is here noted, that in lieu of the spherical bearings  36 , a coupling between each of the arms  34  and the frame  14  could be provided which includes a cylindrical bushing encased in a block of resilient material housed within the end of a given arm  34  that receives a cylindrical pin carried at a given end of the axle  38 . In this case, when the wheels  16  undergo uneven deflection resulting in twisting being applied to the U-shaped assembly composed of the axle  28  and the arms  34 , the resilient material will deflect and absorb forces that would otherwise be transferred to the bearing surfaces established between the bushings and pins. 
     The flange  42  extends generally vertically or at a right angle to the direction of the principle extent of the rectangular tube  40  and is provided with a recess  62  extending in the direction of the main extent of the axle  28  into which the axle  28  can be inserted in certain regions in order to form a positive locking engagement. 
     The cover flange  46  and the bottom flange  48  are identical and configured symmetrically about a generally horizontal plane, this makes it possible to turn the arm  34  through 180° about its longitudinal axis, so that it can be applied on the left and on the right side. The cover flange  46  and thereby the bottom flange  48  as well are used, with bores provided in them, for the removable engagement of a stop  64  that is configured as a housing in the form of an irregular trapezoid, whose surface provides a seat  66  for a spring  68 , that can be seen in FIG.  4 . In the present embodiment, the stop  64  is configured in a wedge shape in such a way that, in the installed condition, the seat  66  extends generally parallel to the lower end surface of the spring  68 . On the rear side of the stop  64 , a peg  70  is provided through which a radial bore extends, that is not described in any further detail, which may receive a cotter pin. The peg  70  may be configured as a pin that penetrates the stop  64 . 
     The frame  14  is provided on its rear end on each side with an open-bottomed housing  72 , that is connected, particularly welded, above the spherical bearings  26  to the outside of the frame  14 . The housing  72 , that is open downward and aligned vertically with the seat  66 , is used to engage the spring  68 . On the rear side of the housing  72  and in vertical alignment with the peg  70 , a peg  70 ′ of identical configuration is attached. A bracket  71 , shown only on the left-hand side in FIG. 4, with two bores, whose spacing corresponds to the spacing of the pegs  70  and  70 ′, when the suspension  20  is loaded, can be provided, as shown, engaged with the pegs  70  and  70 ′, so that a relative movement between the arm  34  and the console  44  cannot take place or can do so only to a limited degree if one of the peg-receiving bores is configured as a slot. 
     In the embodiment shown, the spring  68  is configured as a rubber block, that is enclosed in the housing  72  so that it cannot be lost, has an upper surface in contact with the cover of the housing  72  and has a lower surface engaged with the seat  66 . In different embodiments, the rubber block could be replaced by a helical compression spring or a package of Belleville springs. 
     The wheel hubs  30  are configured in the usual manner so that each can engage a wheel  16 . In each of the wheel hubs  30 , a brake shoe arrangement of the braking assembly  32  is provided of which only one actuating arrangement  74  can be seen, which uses linkages and servo motors, not shown. The actuating arrangement  74  is mounted on a plate  76  that can be bolted to the flange  42  of the arm  34  and is provided with a recess, not described in any further detail, that engages the axle  28 . The plate  76  and the flange  42  are clamped to each other by means of screws, not shown. 
     On the basis of the above description, the following configuration and the following operation are the result of the suspension  20  according to the invention. 
     The further axle  38  is inserted through the openings of the connection  26  in the frame  14  and secured centrally. Subsequently, when the frame  14  is raised, the arms  34  are pushed over the projecting regions of the further axle  38 , the balls  50  are pushed on and secured by means of the covers  60 , the removable disks  56  are bolted to the arms  34 , the springs  68  are inserted into the housings  72 , the stops  64  are mounted on the cover flanges  46 , the axle  28  is secured to the flanges  42  by means of the plates  76  and the wheels  16  are mounted on the wheel hubs  30 . If the frame  14  is now lowered, so that the wheels  16  are supported on the ground, then the frame  14  with the springs  68  presses against the seats  66 . During operation, the springs  68  can deflect and dampen the shocks on the frame  14 . If the vehicle rolls into depressions in the ground and the two sides experience different accelerations, then the suspension  20 , that consists generally of the axle  28  and the two arms  34 , can twist and can move freely enough on the further axle  38  on the basis of the spherical bearings  36 , without causing any warping. In lieu of the springs  68  that are made of rubber blocks, to control the rough operation of agricultural implements it is also possible to use springs made of steel, particularly helical compression springs or helical extension springs, Belleville springs or hydraulic gas pressure springs. Further, in the case of large spring deflections or in the case of danger of vibrations or oscillations, it is possible to provide one or more shock absorbers that avoid the build-up of a resonance in the springs. 
     Since in operations over bumpy roads, accelerations can be encountered in the upward as well as the downward direction, it is possible that the springs  68  may be replaced with spring arrangements that operate in both directions. For example, a spring may be provided on either side of the arm or the axle, in particular a rubber block, so that the axle can move only within a short distance and is intercepted by springs in each direction. 
     The fact that the arms  34  may be disconnected from the axle  28  by removing the fasteners that clamp the arm flange  42  and the plate  76  has the advantage that, in the case of damage to the axle or to the arm, the entire assembly need not be replaced. It is also possible with different vehicles to use different arms with the same axles or differing axles with the same arms. Such a flange connection, that can lead to a rigid and stable assembly between the axle and the arms can also be used without the need for flexible arms or other springs, for example, for adjusting the operating height of the vehicle. 
     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.