Abstract:
A drive system for the auger of a crop-harvesting header that includes a slip clutch to slow or stop auger rotation upon encountering a slug or foreign object of sufficient size, and pawls on the drive sprocket that engage a ratchet wheel on the auger drive shaft when the drive is reversed to provide positive power to the auger in reverse to eject the obstruction.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to headers for crop-harvesting machines, and more particularly to an auger header connectable to the forward end of a specialized tractor, thereby forming what is generally know in the agricultural business as a swather or windrower. Even more particularly, the instant invention relates to the use of a slip clutch in the drive system of the auger of crop-harvesting header that allows, upon plugging of the auger, the drive to continue while the auger stops or slows. When the drive is reversed to back out the slug, a ratchet wheel on the auger drive shaft positively powers the auger in reverse, not allowing the clutch to slip. 
     In modern agriculture, especially in regard to harvesting forage crops, it is the present tendency to cut a relatively wide swath of the crop within a range of anywhere between 10 and 16 or more feet in width, and then consolidate the crop into a narrower, substantially continuous windrow, in which form the crop is left to dry in the field until the moisture content has been reduced to a value suitable for subsequent harvesting operations such as baling. The arranging of the crop into a continuous windrow around the field primarily is to facilitate the baling thereof. 
     Many older swather or windrower implements employed endless draper conveyors for purposes of consolidating a relatively wide swath of cut material into a narrower band thereof and then discharged onto the field as a windrow. Such devices offer various types of difficulties in that, as is well known, endless conveyors in agricultural equipment gradually stretch and also are subject to rather rapid wear, especially if carelessly used. 
     The more recent designs of windrower headers employ a consolidating auger operationally behind a cutterhead and rotating reel to receive the cut crop material and convey it centrally of the header from either lateral end portion thereof for feeding into a crop-conditioning mechanism, conditioning rolls, for instance. A header of this type is shown and described in U.S. Pat. No. 3,324,639 issued to L. M. Halls et al. on Jun. 13, 1967. A major problem encountered by such machines relates to plugging. Crop materials, weeds, and combinations thereof sometimes form into balls or tight seemingly large wads, known as slugs, that do not conveniently feed through and along the auger. One way to address this issue is to employ a floating auger, such as shown in the above-identified &#39;639 patent or in U.S. Pat. No. 4,296,592 issued to Irwin D. Mcllwain on Oct. 27, 1981. The floating auger is generally free to move vertically, thus allowing most slugs a better opportunity to follow the auger to the central consolidating area. 
     It would be helpful to have a drive system of the general type herein described with a simpler and more reliable mechanism for handling the slugs that are inevitably encountered during field operations. The instant invention provides such an alternative. 
     SUMMARY OF THE INVENTION 
     Accordingly, one object of the present invention is to provide an alternative mechanism for ejecting or extracting slugs from the auger of a crop-arvesting header. 
     Another object of the present invention is to provide a novel drive mechanism for the auger of a crop-harvesting header including a slip clutch to prevent damage from slugs and to provide a positive reverse drive to either eject slugs or push them into a position for extraction. 
     It is another object of the instant invention to provide a drive mechanism for the auger of a crop-harvesting header including a slip clutch with friction discs to allow the main drive to continue to turn while the auger either stops or slows. 
     Yet another object of the present invention is to provide a drive mechanism for the auger of a crop-harvesting header including pawls on the auger sprocket to engage a ratchet wheel on the auger drive shaft to positively drive the auger in the reverse direction when ejecting slugs. 
     It is yet another object of this invention to provide an improved drive mechanism for the auger of a crop-harvesting header which is durable in construction, inexpensive to manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use. 
     It is a still further object of the instant invention to provide a drive system for the auger of a crop-harvesting header that includes a slip clutch to slow or stop auger rotation upon encountering a slug or foreign object of sufficient size, and pawls on the drive sprocket that engage a ratchet wheel on the auger drive shaft when the drive is reversed to provide positive power to the auger in reverse to eject the obstruction. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein: 
     FIG. 1 is a top plan view of a windrow header employing the teachings of the instant invention; 
     FIG. 2 is an end view of the header of FIG. 1, taken along line  2 — 2  of FIG. 1; 
     FIG. 3 is a cross-sectional view of FIG. 2, taken along line  3 — 3 ; and 
     FIG. 4 is an exploded view of the drive clutch shown in FIG.  3 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring particularly now to FIG. 1, the forward portion of the tractor  10  is shown to include a pair of transversely spaced driving wheels  12  that provide the principal support not only for the tractor, but also the header mechanism  14  and the conditioner unit  16  which are, respectively, independently supported by the forward portion of the tractor  10  by means to be described hereinafter. 
     The header  14  comprises a main frame  18  of substantial width for purposes of permitting the header to harvest a swath of forage crops, or the like, of a substantial range of different widths within the range, for example, of between ten and sixteen or more feet. Particularly where the forage crop does not grow to substantial heights, it is more efficient and economical to cut a relatively wide swath of said material and then consolidate the same into a substantially narrowed windrow in which form the crop dries and from which it is fed to subsequent portable harvesting equipment. The main frame  18  has opposite sides  20  and  22 , which are of substantial length, extending forwardly from the tractor  10 . Said main frame is supported preferably for floating substantially vertical movement to enable the sickle bar assembly  24  normally to be positioned close to the exemplary ground surface  26  (see FIG. 2) by the employment of skids or shoes (not shown) which are fixed to the main frame  18  at opposite sides thereof. The sickle bar assembly  24  also extends between the opposite sides of the main frame  18  so as to cut a swath of material substantially equal to the width of the main frame  18 . 
     The main frame  18  is connected to and supported by the forward end of the tractor  10  by pairs of heavy links  30  and  32  which respectively extend from opposite sides of the tractor  10  and the links of each pair are spaced vertically above each other. By such arrangement of substantially parallel upper and lower links  30  and  32 , the vertical movement of the header  14  with respect to the tractor  10  will be permitted while the header remains generally horizontal in all vertical positions of operation. The supporting structure is well known in the art, as generally shown by U.S. Pat. No. 3,324,639. 
     In the preferred mounting of the header  14  with respect to the forward end of tractor  10 , although the header normally substantially rides upon the skid shoes which slide over the ground, the full weight of the header is by no means sustained by the skid shoes in that appropriate tensioning means, such as springs  28  and  29 , extending from the forward end of tractor  10  sustain the majority of the weight of the header  14 . Further, the fragmentary link means are intended to exemplify an elevating mechanism, not shown in detail, but supported by the forward portion of tractor  10  and arranged to be operated to move the header  14  from its lowermost operative position, as illustrated generally in FIG. 2, to various elevated positions. Such tensioning and elevating mechanisms are not an essential part of the present invention and thus details are not believed to the necessary. 
     To facilitate the movement of crop material toward the sickle bar assembly  24 , a conventional reel  36  extends between the opposite sides of main frame  18  and is rotatably supported for movement about an axis fixed with respect to main frame  18 . The reel preferably is of the type having rows of tines  37  extending from pivoted rods actuated by cams, not shown in detail, in the ends of the reel to cause the rows of tines  37  to produce a sweeping-like motion that rakes and impels the cut crop material up toward the auger consolidating means, and then release the material, just before engagement by the auger. 
     Also supported by main frame  18  rearwardly of the reel  36 , upwardly from and rearwardly of the sickle bar assembly  24 , is an auger  38 , the axis of which is substantially parallel to that of reel  36  and the auger extends between the opposite sides of the frame  18  as is clearly shown in FIG.  1 . The auger comprises a central tube  40  and coaxial therewith at opposite ends are axle means  100  (see FIG. 2) which allow the auger to rotate. 
     A plurality of helical flights  46  respectively extend inwardly from the opposite ends of auger  38  and preferably terminate short of the central portion of the tube  40 , the flights being oppositely spiraled as is best shown in FIGS.  1 . The flights are connected in any appropriate manner to the central tube  40 . The central portion of tube  40  preferably has means by which a plurality of substantially radially extending paddles  48  (only one of which is shown) may be detachably connected to said tube, whereby when the header is used without employment of the conditioner unit  16 , the paddles  48  may be removed because they normally are not required under such circumstances. 
     Also extending transversely between the opposite sides of frame  18  is an arcuate shield  50  which is disposed adjacent the lower and rearward portions of the peripheral confines of the helical flights  46 , but, as best shown in FIG. 2, the shield is at least slightly spaced from such confines. The shield  50  is fixedly connected to main frame  18  for support thereby and, intermediately of the ends thereof, is provided with an exit opening, not shown, which is substantially narrower than the full width of the shield  50 . The exit opening serves to discharge a full swath of cut forage material that has been consolidated by the auger approximately to about one-third of the width of the original swath. 
     To promote the smooth and efficient passage of cut material from the sickle bar assembly  24  to the shield  50 , and especially to promote the passage of cut material beneath the central tube  40  of auger  38 , there is provided an upwardly and rearwardly extending guide means, not shown in detail, but described in U.S. Pat. No. 3,324,639 which is incorporated herein in its entirely by reference. The consolidating auger structure thus far described is commonly known in the art as a “floating” auger. When slugs or foreign objects such as rocks, small animals, tree branches, bushes, and the like are encountered by the harvester, the auger may move upwardly and rearwardly to allow the item to pass, thereby reducing the likelihood of damage to the machine. Unfortunately, there are situations where the slug or foreign object is too large to pass, and the auger becomes clogged and non-operational. Obviously, this can result in costly damage to the machine and extended down time. The present invention, as will be described below, is intended to remedy this problem. 
     The structure to be described includes two primary elements: (1) a slip clutch; and (2) a positively powered reverse drive. 
     Attention is again directed to FIG.  1  and FIG. 2, where it can be seen that the drive system for header  14  initiates with the header drive hydraulic motor  60 , which is, in turn, driven by a hydraulic pump (not shown) powered by the engine of tractor  10 . Through universal transfer shafts  62  and  64  the two conditioner rolls are provided the power to rotate and condition cut crop material. A third universal transfer shaft,  66 , at the opposite end of the upper conditioner roll, rotates driver shaft  68  that extends through the side  22  of header  10 . Driver shaft  68  has affixed thereto on the outward end portion thereof a driver sprocket  70  and a reel drive variable sheave  72 . Thus, motor  60  rotates the conditioner rolls and provides rotational power to the drive sprocket  70  and sheave  72  on the far side of the header. 
     The central shaft  80  of reel  36  is rotated from the left side of header  14  by reel drive sprocket  82 , fixed to shaft  80 . A reel sheave  84  is affixed to stub shaft  86  and to a smaller reel drive sprocket  88 . A drive chain  90  engages the teeth on sprockets  82  and  88  such that rotation of sheave  84  results in rotation of reel  36 . A tensioning sprocket  92  may be provided to maintain the appropriate chain tension. The relative operational diameters of the sprockets and sheaves are selected to provide the appropriate reel speed to ground speed ratios. 
     A v-belt  94  is fitted to the two sheaves  72  and  84  such that rotation of sheave  72  results in rotation of the reel  36 . As discussed above, an adjustable tensioning pulley  96  may be advantageously added to extend the operational life of the v-belt  94  and improve the operation of the drive system. 
     Auger  38  is provided with an axial shaft  100  about which the auger rotates. On the left outward end of shaft  100  there is located a drive sprocket  102 . Drive chain  104  engages the teeth on sprockets  70  and  102  such that rotation of sprocket  102  causes auger  38  to rotate in a relationship determined by the relative diameters of the two sprockets. A tensioning sprocket  106  can be added to take up unwanted slack in chain  104 . 
     For a more detailed explanation of the clutch and positive reverse drive structure, attention is directed to FIGS. 3 and 4. FIG. 4 is an exploded view of FIG. 3, which is a cross-sectional of the left end of the auger shaft  100 . Drive sprocket  102  is loosely fitted onto shaft  100 , i.e., it is not fixed to the shaft and can rotate independently thereon. Drive sprocket  102  can be selectively powered, as part of the drive system described above, to rotate in either the forward direction (F) or the reverse direction (R) as indicated by arrow  105 . A driven hub  106  is fixed to shaft  100  by an appropriate means, such as, for example, a key and lock nut, so that hub  106  does not slip relative to the shaft. The hub is also formed with a protruding collar,  110 , thereon with threaded boltholes therein for purposes to be described below. A pair of friction discs,  112  and  114 , one on either side of sprocket  102 , are positioned to engage the planar surfaces of sprocket  102 . Ring  116  is next in line, and has a generally triangular-shaped opening,  118 , centrally therethrough so that it is not solidly affixed to shaft  100 . A disk spring  120 , or pressure plate, somewhat like a Belleville washer, is next. An end plate, or cover,  124  forms the terminal end of assembly. End bolts  126  extend through end plate  124  and the semi-circular cutouts in pressure plate  120 , through the central openings in the friction discs and sprocket and into threaded boltholes in collar  110 . When tightened, bolts  126  pull all of the elements together into a sandwich-like assembly, as shown in FIG. 3, that initially functions as a slip clutch. 
     When the header drive is operating in the forward direction, shaft  100  will rotate so long as the braking force set by the pressure plate  120  or the frictional forces between the friction discs  112  and  114  and sprocket  102  are not overcome by forces in the opposite direction created by a slug or foreign object in contact with the auger. When such forces are encountered, the operator would reverse the header drive to try to push the object out of the auger; however, in many instances this mere reversal does not provide sufficient force to reach this objective, i.e., the slip clutch slips both in the forward and reverse directions. 
     It has been determined that the problem discussed immediately above may be overcome by developing a more positive reverse drive, i.e., a drive that does not allow the clutch to slip in the reverse direction. Continuing to look at FIGS. 3 and 4, it can be seen that the outer edge of ring  116  is formed with uniformly spaced ratchet teeth  108  thereabout. A pair of opposing pawls,  130 , are pinned to sprocket  102  and located in the assembly to engage teeth  108 . Thus, when the drive system is causing the slip clutch to slip in the forward direction, pawls  130  ride over teeth  108 , and when working in the reverse direction, the pawls  130  engage teeth  108  and positively drive shaft  100 . The pawls may be advantageously biased into contact with teeth  108  by, for example, springs  132 . While two pawls are shown, it is to be understood that any reasonable number may be employed. 
     On the side of the main frame opposite the auger and reel drives there is a conventional sickle bar drive assembly  140 . This assembly, not forming a significant part of this invention, is also powered by hydraulic motor  60  and operates in a conventional manner. It is clearly possible to replace this sickle bar with another type of cutting mechanism, such as, for example, a disc cutterhead. 
     It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the inventions. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown.