Abstract:
A retracting finger auger assembly is provided with a limiter inside the auger tube of the assembly that is disposed to make temporary engagement with the internal eccentrically offset finger shaft of the retracting finger mechanism in the event of flexure of the finger shaft beyond a predetermined amount. In a preferred embodiment, the limiter comprises a transverse, annular member with a guide ring of anti-friction material circumscribing the finger shaft, the member being secured to the interior surface of the auger tube for rotation therewith. The anti-friction guide ring is normally maintained slightly out of contacting engagement with the finger shaft, but is disposed to be engaged as necessary by the flexing shaft to limit such flexing and prevent over-retraction of the retracting fingers.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to retracting finger auger assemblies utilized in grain harvesting headers and the like and, more particularly, to a retracting finger auger assembly having means for preventing the fingers thereof from retracting too far into the auger tube and causing damage or catastrophic failure. 
       BACKGROUND AND SUMMARY 
       [0002]    Retracting finger auger assemblies are well known in the art and have been used for many years to converge crop materials centrally and then feed them rearwardly. Typically, the auger assembly is set up such that the fingers extend as they engage crop material at the front of the auger and retract as they release material at the back. 
         [0003]    A typical retracting finger auger assembly has a stationary crank shaft within the auger tube and fingers that are pivotally mounted on an eccentrically offset finger shaft portion of the crank shaft. The auger tube rotates while the crank shaft remains stationary, but because the fingers project outwardly through holes in the auger tube, they are driven around the finger shaft by the auger tube as it rotates. Because the auger tube rotates about one axis while the fingers pivot about the axis of the offset finger shaft, the fingers extend and retract through the holes in the auger tube as they revolve about the finger shaft. 
         [0004]    In some conditions, particularly if the finger shaft is long and unsupported in the middle, the finger shaft can bounce around within the auger tube and flex to such an extent that one or more of the fingers may become over-retracted into the interior of the auger tube. When that happens, significant damage and catastrophic failures can result. 
         [0005]    Accordingly, the present invention is intended to eliminate this over-retraction problem. In a preferred embodiment, each long run of a finger shaft within an auger tube is provided with a flex limiter that is disposed to block excessive flexing of the finger shaft. Anti-friction surfaces associated with the flex limiter are secured to the auger tube for movement therewith relative to the finger shaft but are disposed to be engaged by the finger shaft when necessary to prevent untoward flexing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a left front isometric view of a harvesting header utilizing a retracting finger auger assembly in accordance with the principles of the present invention, portions of the harvesting reel being broken away to reveal details of construction of the auger assembly; 
           [0007]      FIG. 2  is an enlarged, fragmentary, longitudinal cross sectional view through the left end of the auger assembly illustrating internal details of construction; 
           [0008]      FIG. 3  is a similarly enlarged, fragmentary longitudinal cross sectional view of the opposite, right end of the auger assembly; 
           [0009]      FIG. 4  is a transverse, vertical cross sectional view through the left end of the header just inboard of the drive mechanism on the header revealing internal details of construction of the auger assembly; 
           [0010]      FIG. 5  is an enlarged, fragmentary isometric view of the auger assembly illustrating the relationship between a flex limiter and a finger shaft of the assembly; 
           [0011]      FIG. 6  is an exploded isometric view of a flex limiter illustrating details of construction; and 
           [0012]      FIG. 7  is an enlarged, fragmentary longitudinal cross sectional view through the auger assembly illustrating the relationship between a flex limiter and its finger shaft. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    The present invention is susceptible of embodiment in many different forms. While the drawings illustrate and the specification describes certain preferred embodiments of the invention, it is to be understood that such disclosure is by way of example only. There is no intent to limit the principles of the present invention to the particular disclosed embodiments. 
         [0014]    In  FIG. 1  a retracting finger auger assembly  10  in accordance with the present invention is shown as part of a grain harvesting header  12  having a sickle  14  for severing standing crop materials from the ground. A rotary reel  16  assists in such severance and helps feed the severed materials rearwardly to auger assembly  10 . It will be appreciated, however, that the principles of the present invention are not limited to the particular header  12  selected for illustration and that such principles can be used in a variety of different header constructions and auger assemblies. 
         [0015]    In the illustrated embodiment, auger assembly  10  extends substantially the entire width of header  12  and includes a long auger tube  18  having a cylindrical sidewall  20 . Oppositely inclined auger flighting  22  and  24  on opposite left and right halves of the tube  20  are disposed to converge cut crop centrally of header  12  for subsequent discharge rearwardly therefrom into a feeder house  26  or the like ( FIG. 4 ) of a combine harvester (not shown) to which header  12  is attached. 
         [0016]    Auger tube  18  is supported at its opposite ends for driven rotation about the longitudinal axis of tube  18 . In this respect, the left end of auger tube  18  as illustrated in  FIG. 2  has an end panel  28  fixed to sidewall  20 , the end panel  28  in turn having a stub shaft  30  fixed axially thereto and projecting outwardly therefrom. Stub shaft  30  is rotatably supported by a bracket  32  on the header and a bearing assembly  34 , and a sprocket  36  is attached to the outer end of stub shaft  30  for receiving driving power from a chain drive (not shown) and utilizing such input to rotate tube  18 . 
         [0017]    At the opposite, right end of auger tube  18  as illustrated in  FIG. 3 , a bracket  38  on the header carries a normally stationary stub shaft  40  that projects from bracket  38  into the end of auger tube  18  coaxially with the longitudinal axis of tube  18  and stub shaft  30 . A pair of axially spaced bulkheads  42  and  44  within the right end of auger tube  18  are provided with bearing assemblies  46  and  48  respectively for the purpose of rotatably supporting auger tube  18  on stationary stub shaft  40 . Thus, the right end of auger tube  18  is rotatably supported on stub shaft  40 , which remains stationary, while the left end of auger tube  18  rotates with stub shaft  30  which, in turn, is driven by sprocket  36 . 
         [0018]    Auger assembly  10  further includes a retracting finger mechanism  50  that broadly includes two primary components, i.e., a set of retracting fingers  52  and a stationary crank shaft  54  that carries fingers  52 . In the illustrated embodiment, fingers  52  are located generally along the full length of auger tube  18 , although it is to be appreciated that the principles of the present invention are not limited to this arrangement. For example, it is possible that fingers  52  might be provided only in the central region of auger tube  18 , leaving the two flighted portions thereof essentially finger-free. In any event, in the illustrated embodiment, crank shaft  54  is full length of auger tube  18  and is divided into three sections, comprising a right section, a central section and a left section. 
         [0019]    Each such section of crank shaft  54  includes a laterally offset shaft portion comprising a finger shaft  56  that extends parallel to the axis of rotation of auger tube  18  in eccentric relationship therewith. Opposite ends of each offset finger shaft  56  are provided with cranks  58  and  60  that are in turn fixed to portions of crank shaft  54  that are coaxial with the axis of rotation of auger tube  18 . 
         [0020]    Starting with the left end of left finger shaft  56   a  as illustrated in  FIG. 2 , it will be seen that crank  60  is fixed to a stub shaft  62  journaled by a bearing assembly  64  in a support bulkhead  66  that is fixed to sidewall  20  of auger tube  18 . At the opposite end of finger shaft  56   a  in  FIG. 2 , crank  58  is fixed to a stub shaft  68  that is journaled by a bearing assembly  70  carried by a support bulkhead  72  fixed to sidewall  20 . Stub shaft  68  projects axially through support bulkhead  72  into the central area of auger tube  18  and at that location is fixed to the crank  60  associated with the central finger shaft  56   b . As shown in  FIG. 3 , the central finger shaft  56   b  at its right end has its crank  58  fixed to a stub shaft  74  that is journaled by a bearing assembly  76  in a support bulk head  78  fixed to sidewall  20 . After passing through bulkhead  78 , stub shaft  74  fixedly connects to crank  60  associated with the right finger shaft  56   c , which is fixed at its outboard end to its other crank  58 . Crank  58  of right finger shaft  56   c  is in turn fixed to stub shaft  40  projecting inwardly from header support structure  38 . 
         [0021]    Each of the fingers  52  is pivotally mounted on its finger shaft  56  for rotation about the axis of finger shaft  56 . As illustrated perhaps best in  FIGS. 5 and 7 , each finger  52  preferably comprises a metal finger tube  80  that is replaceably received within a plastic holder  82  rotatably carried on finger shaft  56 . A cotter pin  84  or the like may be used to releasably retain each finger tube  80  within its corresponding holder  82 . 
         [0022]    The outer end of each finger tube  80  projects through and is slidably received by a guide  86  fixedly secured within a mounting hole in the sidewall  20  of auger tube  18 . In the left and right portions of auger tube  18 , finger guides  86  are disposed at diametrically opposed and axially spaced positions along auger tube  18 , while in the central portion of auger tube  18 , finger guides  86  are preferably arranged in side-by-side groups of two or three at suitable intervals about tube  18 . 
         [0023]    As a result of this construction, when auger tube  18  is rotated by drive sheave  36  in a counterclockwise direction viewing  FIG. 4 , crank shaft  54  remains stationary but fingers  52  are driven about their finger shafts  56  by the rotating tube  18 . Due to the offset relationship between finger shafts  56  and the axis of rotation of auger tube  18 , fingers  52  sequentially extend and retract during each complete revolution. Because auger tube  18  rotates in a counterclockwise direction viewing  FIG. 4  and the finger shafts  56  are offset toward the front, fingers  52  are caused extend forwardly along the front of auger tube  18  and to retract along the backside thereof. At other locations between these two extremes, the fingers are either being retracted (as they move down and under the auger tube) or extended (as they move up and over the auger tube). 
         [0024]    It will be appreciated that, particularly in the left and right sections of the auger tube  18 , finger shafts  56  are quite lengthy compared to the diameter of such shafts. Therefore, there is a tendency for finger shafts  56  to bounce and flex during rotation of auger assembly  10 . Such action is particularly likely to occur when some of the fingers  52  encounter unanticipated loads. For example, when fingers  52  are fully extended on the front side of auger tube  18 , the outboard portions of fingers  52  have significant mechanical advantage over the inboard portions thereof. Thus, a load experienced by the exterior portion of the finger can cause the finger to fulcrum about the finger guide  86  and flex the finger shaft  56  in a way that may seek to retract fingers  52  on the opposite side of auger  18  more than their intended amount. If one of the fingers  52  becomes retracted so far that it is pulled back inside auger tube  18 , it can punch a hole in the auger tube as it attempts to extend during the extension phase of the finger, or cause catastrophic failure of the mechanism. 
         [0025]    In accordance with the present invention, each of the left and right finger shafts  56   a  and  56   b  is provided with at least one flex limiter  88  between the supporting bulkheads for the finger shaft. Each flex limiter  88  includes a transverse, annular, metallic member  90  having a circular periphery  92  that is welded or otherwise permanently affixed to the interior surface of sidewall  20  approximately mid-length of the finger shaft  56   a  or  56   c . Annular member  90  extends at right angles to the longitudinal axis of auger tube  18  and has a centrally located, enlarged circular opening  94  through which the finger shaft  56   a  or  56   c  passes. Opening  94  is concentrically disposed with respect to the axis of rotation of auger tube  18 . A front face  96  of member  90  slopes gradually in the axial direction as opening  94  is approached. 
         [0026]    Flex limiter  88  further includes an anti-friction guide ring  98  disposed concentrically within annular member  90  and securely fastened thereto. In one preferred form of the invention, guide ring  98  is constructed from ultra high molecular weight (UHMW) polyethylene, although other materials may also be utilized. Guide ring  98  circumscribes the corresponding finger shaft  56   a ,  56   b  and has a radially inner surface  100  that is normally slightly spaced radially outwardly from the outer extremity of finger shaft  56  so that surface  100  does not normally contact finger shaft  56  during rotation of auger tube  18 . However, in the event of slight outward flexing of finger shaft  56 , surface  100  comes into engagement with shaft  56  and prevents further flexing thereof, thereby also preventing further retraction of those fingers  52  that are already fully retracted to the extent illustrated in  FIGS. 5 and 7 , for example. Longer than momentary engagement of finger shaft  56  with surface  100  can be accommodated, if necessary, due to the anti-friction nature of the material from which guide ring  98  is constructed. Inner surface  100  defines a circular hole  106  that is concentric with opening  94  and has a slightly smaller diameter. 
         [0027]    Guide ring  98  also has a circumferential, radially outwardly extending lip  102  integral with surface  100  and overlying a portion of the front face  96  of transverse member  90 . Lip  102  serves as the means by which guide ring  98  is secured to annular member  90 , having a plurality of suitable fasteners  104  that project through lip  102  and into retaining engagement with member  90 . In one preferred form of the invention, fasteners  104  may take the form of machines screws. Preferably, guide ring  98  is formed from two semi-circular halves, as shown particularly in  FIG. 6 . 
         [0028]    It will be noted that each flex limiter  88  does not interfere with rotation of auger tube  18  or extension and retraction of fingers  52 . In normal operating conditions, limiters  88  do not make engagement with their finger shafts  56   a ,  56   c . However, in the event that any of the fingers  52  experiences unusual loading such as would normally cause a shaft  56   a  or  56   c  to flex, the corresponding limiter  88  is well positioned to engage the slightly flexed shaft before it can move to such an extent that damage or catastrophic failure can occur. 
         [0029]    The inventor(s) hereby state(s) his/their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of his/their invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set out in the following claims.