Abstract:
A round baler having a mobile chassis, a bale-forming chamber supported on the chassis and including a tailgate that can be raised for discharging a bale from the chamber and a bale discharge ramp. A combination pivot and spring assembly attaches the ramp to the chassis below the chamber for movement of the ramp from a raised, standby position to a lowered, unloading position for guiding a bale down to the ground as the bale leaves the chamber. The combination pivot and spring assembly includes an internal spring for yieldably maintaining the ramp in its raised position until a bale exiting the chamber engages the ramp and overcomes the force of the spring to swing the ramp down to its lowered position.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/730,396, entitled BALER UNLOADING RAMP RETURN MECHANISM filed Nov. 27, 2012, which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of Invention 
         [0003]    This invention relates to the field of round balers and, more particularly, to a passive, spring-loaded bale discharge ramp for such machines. 
         [0004]    2. Description of Related Art 
         [0005]    Passive unloading ramps for guiding bales to the ground as they leave the baling chamber have been known and used for many years on round balers. Such ramps are spring-biased to a raised, standby position during normal baling operations but are forced down into a lowered, deployed position by the weight of the bale as it discharges from the baling chamber. The spring returns the ramp to its raised position once the bale rolls off the ramp. 
         [0006]    Conventional designs utilize exposed compression or extension springs as the return mechanism for the ramp. However, such arrangements are highly susceptible to the accumulation of crop residue and dirt that fill up and clog the springs. Additionally, the pivots for the ramps are typically metal on metal and can be noisy or bind up. Lubrication added to the pivots has a tendency to attract and retain even more dirt and residue, which causes the pivots to bind up, work hard, and wear prematurely. Furthermore, assembly of the spring and pivot mechanism can be difficult. 
       OVERVIEW OF THE INVENTION 
       [0007]    The present invention provides a combination pivot and internal spring assembly for the ramp wherein the spring is housed protectively inside the pivot mechanism. Thus, the spring components are not exposed to the deleterious effects of the elements and do not collect trash and dirt. Furthermore, the spring components are so positioned that they help seal off and close opposite, otherwise open ends of a tubular member of the pivot to resist the ingress of harmful trash and dirt, as well as moisture, into the interior of the pivot. Moreover, the spring components support the rotatable part of the pivot in such a manner that no bearings are needed and there is no metal-to-metal contact of any kind within the pivot. In one preferred embodiment of the invention resilient rubber-like or elastomeric spring pads within the tubular outer member of the pivot assembly are compressed when the outer member is rotated relative to a stationary inner member as a discharging bale swings the ramp down to the ground, thereby torsionally loading the pivot assembly to effect automatic return of the ramp to its raised position once the bale rolls off the ramp. 
         [0008]    In one embodiment, the invention is directed to a round baler having a mobile chassis, a bale-forming chamber supported on the chassis and including a tailgate that can be raised for discharging a bale from the chamber and a bale discharge ramp. A combination pivot and spring assembly attaches the ramp to the chassis below the chamber for movement of the ramp from a raised, standby position to a lowered, unloading position for guiding a bale down to the ground as the bale leaves the chamber. The combination pivot and spring assembly includes an internal spring for yieldably maintaining the ramp in its raised position until a bale exiting the chamber engages the ramp and overcomes the force of the spring to swing the ramp down to its lowered position. In one embodiment, the combination pivot and spring assembly further include a stationary member fixed to the chassis and a rotatable member fixed to the ramp for rotational movement relative to the stationary member when the ramp moves between the raised and lowered positions, and the spring is operatively disposed between the members. 
         [0009]    These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods according to this invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The above mentioned and other features of this invention will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0011]      FIG. 1  is a left side elevational view of a round baler incorporating a spring-loaded, passive unloading ramp in accordance with the principles of the present invention, the ramp being shown in the raised position; 
           [0012]      FIG. 2  is a left side elevational view similar to  FIG. 1  but showing the tailgate raised and the ramp forced down to its lowered position by a discharging bale; 
           [0013]      FIG. 3  is a left, rear isometric view of the baler with the tailgate closed and the ramp in the raised position corresponding to  FIG. 1 ; 
           [0014]      FIG. 4  is a left, rear isometric view of the baler with the tailgate raised and the ramp in the lowered position corresponding to  FIG. 2 ; 
           [0015]      FIG. 5  is an enlarged, fragmentary, left rear isometric view of the ramp in the raised position with parts broken away to review details of construction; 
           [0016]      FIG. 6  is an enlarged, fragmentary, right, rear, bottom isometric view of the ramp in the raised position; 
           [0017]      FIG. 7  is an enlarged, left rear isometric view of the ramp and its associated pivot assembly; 
           [0018]      FIG. 8  is an enlarged, left, front, bottom isometric view of the ramp and its associated pivot assembly; 
           [0019]      FIG. 9  is an enlarged, fragmentary top plan view of the left end of the ramp and associated pivot assembly with parts broken away to reveal details of construction; 
           [0020]      FIG. 10  is an enlarged, fragmentary cross-sectional view through the ramp and associated pivot assembly illustrating the condition of things when the ramp is in its raised position; 
           [0021]      FIG. 11  is a view of the ramp and associated pivot assembly similar to  FIG. 10  but showing the condition of things when the ramp is in the lowered position; and 
           [0022]      FIG. 12  is an exploded, left front isometric view of the ramp and associated pivot assembly. 
       
    
    
       [0023]    Corresponding reference characters indicate corresponding parts throughout the views of the drawings. 
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0024]    The invention will now be described in the following detailed description with reference to the drawings, wherein preferred embodiments are described in detail to enable practice of the invention. Although the invention is described with reference to these specific preferred embodiments, it will be understood that the invention is not limited to these preferred embodiments. But to the contrary, the invention includes numerous alternatives, modifications and equivalents as will become apparent from consideration of the following detailed description. 
         [0025]    A round baler  10  has a wheeled mobile chassis  12  that supports a baling chamber  14  for forming a round bale from crop materials picked up from a field as the baler is towed across the field. At the completion of a bale-forming cycle, a tailgate  16  that comprises the rear half of baling chamber  14  is raised to allow a finished bale  17  to roll out of the chamber by gravity and onto the ground. A passive, spring-loaded unloading ramp  18  is provided to guide bale  17  to the ground as it discharges from chamber  14 . During baling operations, ramp  18  is disposed in a raised position as shown, for example, in  FIGS. 1 and 3 , but as bale  17  engages ramp  18  during discharge, the weight of the discharging bale forces ramp  18  down to a lowered position as shown, for example, in  FIGS. 2 and 4  in which the rear end of ramp  18  engages the ground. After the bale has rolled off ramp  18 , the ramp automatically returns by spring force to its raised position, and tailgate  16  is reclosed by the operator. 
         [0026]    In accordance with the present invention, ramp  18  is attached to chassis  12  below baling chamber  14  by a combination pivot and spring assembly  20  wherein spring components of the assembly are internally disposed. Ramp  18  may be constructed in a number of different ways without departing from the principles of the present invention, but in the particular embodiment disclosed herein it comprises three fore-and-aft extending, laterally spaced apart and transversely U-shaped, inverted channels  22  that are interconnected across their rear ends by a common transverse pipe  24 . At their front ends channels  22  are interconnected by a common, inverted L-shaped beam  26  having a vertical rear leg  28  and a horizontal top leg  30 . Three pairs of generally C-shaped, upright mounting lugs  32  project forwardly from vertical leg  28  beneath horizontal leg  30  for use in attaching ramp  18  to combination pivot and spring assembly  20  as hereinafter described. 
         [0027]    Combination pivot and spring assembly  20  includes a hollow outer pivot member, preferably in the form of an elongated tube  36 , that rotates with ramp  18  during movement of the ramp between its raised and lowered positions. In the particular illustrated embodiment, tube  36  has a four-sided, rectangular cross-sectional configuration, although it will be appreciated that tube  36  may have a lesser or greater number of sides and need not necessarily be polygonal in cross-section. Tube  36  extends parallel to beam  26  and is complementally received within the forwardly facing mouths of mounting lugs  32 , while a pair of U-bolts  38  fixedly secure tube  36  and beam  26  together. Opposite ends of tube  36  project slightly outwardly beyond the outermost mounting lugs  32  as shown, for example, in  FIGS. 7 ,  8  and  9 . 
         [0028]    Combination pivot and spring assembly  20  further includes a stationary inner pivot member, preferably in the form of a pair of axially aligned, longitudinally spaced apart, rectangular stub shafts  42  that project into opposite ends of outer tube  36 . Like tube  36 , stub shafts  42  may each have fewer or greater than four sides and need not necessarily be polygonal in cross-section, although it is advantageous in any event for the sake of simplicity for stub shafts  42  to match the polygonal cross-sectional configuration of outer tube  36 . Outer tube  36  has a somewhat larger cross-sectional configuration than stub shafts  42  and, in the illustrated embodiment, is rotatively offset by approximately  45  from stub shafts  42  when ramp  18  is in its raised position as illustrated, for example, in  FIG. 10 . Consequently, when ramp  18  is in its raised position, a number of generally triangular-shaped voids  44  ( FIG. 10  are presented at the internal corners of tube  36  between flat internal surfaces  45  of tube  36  and opposing flat external surfaces  47  of stub shafts  42  (see also  FIG. 12 . 
         [0029]    An internal spring is provided within tube  36  to interact with tube  36  and stub shafts  42  to form another part of combination pivot and spring assembly  20 . Such internal spring preferably comprises a plurality of resilient, rubber, rubber-like, or elastomeric spring pads or “cords”  46  that occupy the voids  44 . Preferably, the pads  46  are each generally triangular in cross-sectional configuration to match the triangular shape of voids  44 , although other cross-sectional shapes may also be acceptable. As will be seen, the closer the pads  46  match the shape of the voids  44 , the more completely stub shafts  42  and pads  46  will serve to plug and close the otherwise open ends of tube  36 . As illustrated in  FIG. 9 , pads  46  have outermost ends  46   a  that are substantially flush with the corresponding end edges  36   a  of tube  36  at its opposite ends. 
         [0030]    Combination pivot and spring assembly  20  additionally includes a pair of fore-and-aft mounting arms  48  fixed to and projecting forwardly from the outer ends of stub shafts  42 . Mounting arms  48  are spaced a short distance outwardly from the opposite end edges  36   a  (see  FIG. 9  so as to avoid metal-to-metal contact between arms  48  and tube  36  as ramp  18  pivots about the common longitudinal axis of stub shafts  42  and tube  36  during movement between its raised and lowered positions. Mounting arms  48  are, in turn, rigidly attached by bolts  50  ( FIGS. 5 ,  6  to a corresponding pair of generally U-shaped brackets  52  that are affixed by welding or the like to a fixed, transverse axle tube  54  forming part of chassis  12 . 
         [0031]    It should be apparent from the foregoing description that ramp  18  and outer tube  36  pivot about stub shafts  42  during movement between the raised and lowered positions as stub shafts  42  remain stationary. Spring pads  46 , operating against flat surfaces  45  and  47  of tube  36  and stub shafts  42  respectively, yieldably bias ramp  18  toward its raised position and maintain it in such position throughout baling operations. However, when a bale ejects from chamber  14  and engages ramp  18 , the weight of the bale causes ramp  18  and outer tube  34  to rotate downwardly about stub shafts  42  ( FIG. 11 , causing flat surfaces  45  of tube  36  to move in such a direction relative to flat surfaces  47  of stub shafts  42  that spring pads  46  are rolled and significantly compressed. The spring rate of pads  46  is such that they cannot prevent the bale from pushing ramp  18  all the way down to the ground, but once the bale has reached the ground and rolled away from the ramp, the pads  46  overcome the weight of the ramp alone and return it to the raised position as they seek to restore themselves to their less stressed condition. 
         [0032]    Having the spring components for ramp  18  housed internally within the pivot structure for the ramp provides several important benefits. For one thing, it provides a simple, clean and uncluttered design for the ramp. For another, it protects the spring components from the harmful effects of the elements and keeps them free of dirt and residue to avoid the problem of trash accumulation on prior exposed compaction and extension springs. In this respect, having pads  46  essentially flush with the end edges  36   a  of tube  36 , rather than recessed deeply within tube  36 , helps keep materials and moisture from entering into tube  36  in significant amounts. Depending upon the cross-sectional shape selected for pads  46 , the cross-section of tube  36  at end edges  36   a  may essentially completely close that region. Moreover, even though there are no bearings or lubricant as part of the pivot mechanism, there is still no harmful metal-to-metal contact of the component parts. The pads  46  effectively serve not only as return spring mechanism for the ramp, but also as a means of physically isolating the outer tube  36  from stub shafts  42  while allowing the pivoting action to take place. 
         [0033]    One suitable commercially available product for use as the combination pivot and spring assembly  20  is a “Torflex” rubber torsion suspension axle product obtainable from Dexter Axle Company of Elkhart, Ind. Another suitable commercially available product may be obtained from Axis Products, Inc. of Elkhart, Ind. as part of their torsion spring product line. 
         [0034]    In selecting the spring rate for the pads  46  that make up part of assembly  20 , a number of factors are considered. The primary consideration is that the spring must be strong enough to support the weight of the ramp and minimize bouncing of the ramp while the baler travels over a rough field, yet not be so strong that the bale cannot deflect the ramp down to the ground when leaving the baler. If the spring is too strong, the bale will not be allowed to leave the baler. While in many crops this is not a problem because the bales have significant mass, in some crops such as wheat straw, the bales are not as heavy. Thus, the spring rate is selected to be such that the spring is strong enough to hold the ramp in the raised position with a minimal amount of bouncing, but not much stronger than that. 
         [0035]    The foregoing has broadly outlined some of the more pertinent aspects and features of the present invention. These should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Other beneficial results can be obtained by applying the disclosed information in a different manner or by modifying the disclosed embodiments. Accordingly, other aspects and a more comprehensive understanding of the invention may be obtained by referring to the detailed description of the exemplary embodiments taken in conjunction with the accompanying drawings.