Abstract:
A modular rotary cutter bed is formed by a series of essentially identical cutter modules mounted end-to-end along the length of a common support beam. Guards for the cutters of the modules are arranged such that each guard overlaps and bridges the seam between an adjacent pair of modules so as to increase the structural rigidity of the cutter bed. Each guard is attached at its front end to the noses of a pair of adjacent modules and at its rear end to the support beam to increase structural integrity in all directions. A second embodiment does not utilize a common support beam for the modules but instead relies upon the interconnections between adjacent modules and bridging overlap of the guards to rigidify the cutter bed.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to rotary mowers and, more particularly, to a modular rotary cutter bed wherein a series of essentially identical cutter modules, each having at least one rotary cutter, are fitted together in side-by-side relationship across the path of travel of the machine. 
       BACKGROUND AND SUMMARY 
       [0002]    Modular cutter beds have been known for some time. Generally speaking, they are formed by connecting a series of essentially identical cutter modules in end-to-end relationship along a support beam in such a manner that the length of the cutter bed is determined by the number of modules in the series. In some constructions, the modules may simply be secured to each other without being secured to a common support beam such that the resulting assembly is self-supporting. In either case, internal drive mechanisms such as operably interconnected spur gears or shafts and bevel gears form a drive train along the bed and provide driving power to all rotary cutters of the bed. 
         [0003]    Due to the fact that the cutter bed is comprised of a series of interconnected modules, lines of weakness are inherently presented to some extent at the interfaces or seams between abutting ends of the adjacent modules. Thus, the structural integrity of the bed can be compromised to a certain extent, and reliability issues are presented with respect to the interconnected drive mechanisms between the modules. Each module also has its own rock guard with side edges that end at the seam between adjacent modules. Because these guards do not overlap adjacent modules and interconnect with them, the guards provide no assistance in structurally supporting adjacent modules. 
         [0004]    In one conventional arrangement the cutter bed has a scalloped front extremity in which a series of rearwardly projecting notches are interspersed between a series of forwardly projecting arches. This pattern is presented by the rounded noses of the rock guards whose opposite side edges are located at the recessed notches and present fore-and-aft joints at those locations. The cutters of adjacent modules counter-rotate and sweep rearwardly in overlapping paths of travel directly above the notches and joints. Consequently, the cutters tend to drive residue and dirt directly into the joints and can cause it to become tightly wedged in those spaces. A cradle that supports the modules may have grooves worn into it as stubble drags through the joints and into engagement with the cradle. 
         [0005]    In the present invention each rock guard is designed to span the seam between a pair of adjacent modules so that it overlaps the two modules and is secured thereto in a bridging relationship to provide improved structural rigidity. Moreover, the butt joint between adjacent guards on the bed is located substantially in fore-and-aft alignment with the axis of rotation of a cutter so that it is remote from the weak point at the seams between adjacent modules and is in a position where any trash or other residue tending to get trapped can be easily severed by a knife of the cutter instead of being allowed to build up and cause harm. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a top, right, front isometric view of a modular rotary cutter bed constructed in accordance with the principles of the present invention; 
           [0007]      FIG. 2  is an enlarged, fragmentary isometric view of the cutter bed of  FIG. 1  taken from a vantage point located behind the cutter bed and with only a portion of the bed being illustrated; 
           [0008]      FIG. 3  is an enlarged, top, left, front isometric view of a typical cutter module with the rotary cutter removed to reveal details of construction; 
           [0009]      FIG. 4  is a bottom isometric view of the cutter module of  FIG. 3 ; 
           [0010]      FIG. 5  is a fragmentary, left front isometric view of the cutter bed with a pair of modules separated to reveal details of construction and with the rotary cutters removed; 
           [0011]      FIG. 6  is a left, front exploded isometric view of a rock guard in accordance with the present invention, the top, forward lip of the guard being illustrated as separated from the bottom pan of the guard to reveal configuration details; 
           [0012]      FIG. 7  is a left front isometric view of a guard similar to  FIG. 6  but showing the top lip welded in place on the bottom pan in its assembled condition; 
           [0013]      FIG. 8  is a left top isometric view of a guard; 
           [0014]      FIG. 9  is a left bottom isometric view of a guard; 
           [0015]      FIG. 10  is a fragmentary, left front isometric view of the bed with the cutters removed and illustrating the manner in which the guards are attached to the modules; 
           [0016]      FIG. 11  is a fragmentary bottom plan view of the bed with some of the guards bolted in place and one additional guard removed from its final position to reveal details of construction; 
           [0017]      FIG. 12  is a transverse cross-sectional view through the bed taken substantially along line  12 - 12  of  FIG. 2 ; and 
           [0018]      FIG. 13  is a transverse cross-sectional view through a second embodiment of the invention wherein no support beam is utilized and the cutting modules are self-supporting by virtue of their interconnections to and with one another. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    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. 
         [0020]    The rotary cutter bed  10  in  FIG. 1  is adapted to be attached to support structure (not shown) that renders cutter bed  10  suitable for use as part of a harvesting header, mower or other machine. See, for example, the header in U.S. Pat. No. 6,158,201, which patent is hereby incorporated by reference in its entirety into the present specification. In the embodiment of  FIGS. 1-12 , a support frame or chassis of cutter bed  10  is defined in part by an elongated beam  12  that normally extends transversely of the path of travel of the mowing machine during use. As illustrated particularly in  FIGS. 2 ,  5  and  12 , beam  12  includes a generally reclined h-shaped member  14  having an upper, generally horizontally extending flange  16 , a lower generally horizontally extending flange  18  spaced below flange  16 , and a rearwardly projecting tail  20  that forms an extension of flange  18 . Upper flange  16  is welded to lower flange  18  and tail  20  so as to form a secure weldment. A transversely square tubular member  22  is received within h-shaped member  14  and welded thereto to provide additional structural strength for beam  12 . A pair of brackets  24  and  26  adjacent opposite ends of bed  10  are fixed to beam  12  for use in securing beam  12  to structural parts of the mowing machine. 
         [0021]    Generally speaking, as illustrated in  FIG. 1  a series of essentially identical cutter modules  28  are secured to beam  12  along the length thereof and project forwardly therefrom. In some embodiments (not shown), there may be relatively short “dummy” modules between adjacent cutter modules depending upon the type of internal drive mechanism used for the cutter bed, i.e., short shafts may be housed within such dummy modules to interconnect the drives of adjacent cutter modules. Each module  28  primarily includes a generally rectangular, flat, hollow housing or gear case  30 , internal drive mechanism  32  housed within gear case  30 , and an external rotary cutter  34  that is positioned outside of and on top of gear case  30  for rotation by drive mechanism  32 . It will be appreciated that each of these three major components may be modified in a variety of ways without departing from the principles of the present invention, e.g., drive mechanism  32  may comprise a collection of drive shafts and intermeshing bevel gears instead of the spur gear arrangement illustrated in the preferred embodiment. 
         [0022]    Each hollow gear case  30  is open at its opposite ends such that the chamber defined within the gear case communicates with the chambers of adjacent modules when the modules are secured in place along support beam  12 . In this way, the interior chambers of the modules can form a reservoir to contain an oil bath for the drive mechanism  32 . As illustrated in  FIG. 5 , a seal  36  may be clamped between each adjacent pair of the gear cases  30  to prevent oil leakage. 
         [0023]    Each gear case  30  has a pair of opposite flat ends  38 . One end  38  has a pair of fastening bolts  40  projecting therefrom (see in particular  FIGS. 4 ,  5 ), while the opposite end has a pair of through holes  42  for receiving bolts  40  of an adjacent module. Nuts  43  at such opposite end of each gear case  30  may be tightened on bolts  40  to securely fasten adjacent gear cases  30  together. Thus, when all of the modules  28  are butted up against one another along beam  12  and bolts  40 /nuts  43  are securely tightened in place, the abutting ends  38  of modules  28  present a series of fore-and-aft extending interfaces or seams  44  along the cutter bed. Each gear case  30  may be provided with a pair of ribs  46  at opposite ends  38  thereof immediately adjacent seams  44  and extending in a fore-and-aft direction along the same to enlarge the surface area against which seals  36  may be compressed. 
         [0024]    Each gear case  30  has a pair of rearwardly projecting mounting ears  48  at spaced apart locations along the rear edge thereof. As shown in  FIGS. 5 ,  10  and  12  ears  48  are adapted to be received between upper and lower flanges  16 ,  18  of h-shaped member  14 . A pair of carriage bolts  50  pass vertically through flanges  16 ,  18  and receiving holes  52  in ears  48  ( FIG. 5 ) for securely fastening each module  30  to beam  12 . At the front of each gear case  30 , an arcuate, flange-like nose  54  projects forwardly from the rest of the gear case and is provided with a plurality of mounting holes  56  for use in attaching guards to modules  28  as hereinafter described in more detail. Each gear case  30  also has a centrally disposed circular opening  58  in its top wall as illustrated in  FIG. 12 , providing access to the interior of the gear case. A circular cover plate  60  overlies each opening  58  and is secured in place by a plurality of removable screws  62 . 
         [0025]    As noted earlier, drive mechanism  32  may take a number of different forms. In the illustrated embodiment, mechanism  32  comprises three spur gears including a large central spur gear  64  ( FIG. 12 ) and a pair of smaller spur gears  66  on opposite sides thereof (see  FIGS. 3 and 4 ). Smaller spur gears  66  mesh with large spur gear  64  so as to transfer driving power to and away from large gear  64 . Spur gears  66  project slightly beyond the flat ends  38  of each gear case  30  so that, when modules  28  are bolted in place along beam  12 , spur gears  66  of one module intermesh with spur gears of the next adjacent modules to form a complete gear train along the length of cutter bed  10 . 
         [0026]    In the illustrated embodiment, the eight rotary cutters  34  in the center of cutter bed  10  are intended to be driven in oppositely rotating pairs. Thus, successive large gears  64  along cutter bed  10  have two smaller gears  66  between them to yield the proper direction of rotation. In the event that it is desired for adjacent cutters to rotate in the same direction, an odd number of smaller spur gears  64  would be provided in the gear train between each pair of larger gears  64 . In the illustrated embodiment in  FIG. 1 , it is preferable that the two most outboard rotary cutters  34  at each end of cutter bed  10  rotate inwardly in the same direction so as to convey crops cut by the two most outboard cutters toward the center of the machine (as in the incorporated U.S. Pat. No. 6,158,201). It is within the ambit of the present invention however, that all of the rotary cutters  34  in one half of cutter bed  10  could rotate in the same direction toward the center while all of the rotary cutters in the opposite half of the cutter bed  10  could rotate inwardly toward the center in the opposite direction. 
         [0027]    Each large spur gear  64  has an integral, upright shaft  68  that defines the axis of rotation of the particular cutter  34 . As illustrated in  FIG. 12 , each shaft  68  projects upwardly through a bore  70  in the corresponding cover plate  60  and is journaled for rotation by a bushing or bearing set  72 . 
         [0028]    Each rotary cutter  34  comprises a generally elliptical carrier plate  72  and a pair of free-swinging knives  74  at opposite ends thereof. Each knife  74  is swingably attached to the carrier plate  72  by a pivot bolt  76  so that knife  74  swings out to a radially outwardly directed position during operation as a result of centrifugal force, but can yield if necessary when a hard object is encountered. 
         [0029]    As illustrated in  FIG. 12 , each carrier plate  72  is mounted on a hub  78  that is, in turn, secured to its corresponding shaft  68  by splines  80  on shaft  68  ( FIG. 5 ), a washer  82 , and a nut  84 . A cap  86  overlies the top end of shaft  68  and nut  84 , while a series of screws  88  secure cap  86  and carrier plate  72  to hub  78 . The paths of travel of knives  74  of adjacent cutters  34  overlap one another along the line of centers defined by the row of shafts  68 , but adjacent cutters  34  are 90° out of phase with one another so that there is no risk of knives  74  of adjacent cutters striking each other. 
         [0030]    In the illustrated embodiment, each of the two endmost cutters  34  is provided with an upright, crop conveying cage  90  to help consolidate cut crop inwardly toward the middle of cutter bed  10  during operation. An intermediate conveying cage  92  is also utilized in the illustrated embodiment between the two cages  90  and is supported by overhead structure (not shown). All of the cages  90 ,  92  rotate in a direction such that their front peripheries are disposed to move crop inwardly toward the middle of cutter bed  10 . 
         [0031]    Modules  28  are provided with a number of guards  94  along the length of cutter bed  10 . Details of construction of each guard  94  are illustrated particularly in  FIGS. 6-12 . As shown in those figures, each guard  94  has a lower pan or skid  96  that is generally concave in a fore-and-aft direction to present a pair of laterally spaced, slightly upwardly and rearwardly upturned rear tabs  98  and  100  at its rear end and a generally upwardly facing flat margin  102  at its front end. Pan  96  is constructed from sheet metal material and has four bolt holes  104  along the rear thereof in tabs  98 ,  100  for the purpose of receiving fasteners  106  that attach the rear pan  96  to tail  20  of beam  12 . A notch  108  is defined between the two tabs  98 ,  100  at the rear of each guard  94 . 
         [0032]    As illustrated in the figures, pan  96  is generally rectangular in overall configuration, although the two opposite side edges  110  and  112  converge slightly toward one another as the rear extremity is approached, following an initial front portion of each edge  110 ,  112  that is parallel to the opposite edge. The front edge  114  of each pan  96  is scalloped so as to present a pair of forwardly convex sections  116  and  118  on opposite sides of a rearwardly indented central portion that defines a notch  120 . 
         [0033]    Each guard  94  also includes a top lip  122  having a front edge  124  that is configured in the same manner as front edge of  114  of pan  96 . Thus, front edge  124  of each lip  122  has a pair of convexly forwardly curved sections  126  and  128  on opposite sides of a rearwardly indented notch  130 . Lip  122  is welded to pan  96  along the interface of lip  122  with the flat margin  102  of pan  96  such that lip  122  projects rearwardly from margin  102  to overhang and be spaced above downwardly inclined regions of pan  96 . Front edge  124  of lip  122  and front edge  114  of pan  96  are disposed in vertical registration with one another to provide a front edge  132  on guard  94  that corresponds in shape to front edge  114  of pan  96  and front edge  124  of lip  122 , i.e., front edge  132  of guard  94  has a pair of convexly forwardly arcuate segments  134  and  136  on opposite sides of a centrally disposed, rearwardly indented notch  138 . 
         [0034]    Lip  122  has a rear edge  140  provided with a centrally disposed, straight transverse segment  142  and a pair of forwardly convexly arcuate segments  144  and  146  at opposite ends of straight segment  142  and which are concentric with corresponding front edge segments  134  and  136 . A total of four bolt holes  148  are provided along rear edge  140  for mounting purposes as hereinafter explained. Further, opposite side edges  150  and  152  of lip  122  are provided with semi-circular notches  154  and  156  that overlie and are in vertical registration with corresponding semi-circular notches  158  and  160  in pan  96 . As will be seen, each superimposed pair of notches  154 ,  158  and  156 ,  160  serves to define one-half of an access hole when guard  94  is installed on cutter bed  10 . 
         [0035]    Guards  94  are installed in such a manner that each of them spans or bridges a corresponding seam  44  between a pair of adjacent modules  28 . In other words, instead of each module  28  having its own guard  94 , each guard  94  is shared by a pair of adjacent modules  28 , i.e., half of each guard  94  overlaps one module while the other half overlaps the next adjacent module. In this relationship, notch  138  of each guard  94  is disposed in fore-and-aft alignment with a corresponding seam  44 , while the opposite end edges  150 ,  152  of each lip  122  are disposed in fore-and-aft alignment with corresponding upright shafts  68  of a pair of adjacent cutters  34 . Thus, each lip edge  150  cooperates with the edge  152  of the adjacent guard lip to define a fore-and-aft extending joint  162  between the lips of adjacent guards that is in fore-and-aft alignment with the axis of rotation of the corresponding cutter  34  as defined by the shaft  68 . Similarly, the semi-circular notches  154 ,  158  on one guard  94  cooperate with the semi-circular notches  156 ,  160  of the next adjacent guard  94  to define an access hole  164  for accessing the underside of pivot bolts  76  of knives  74  for installation and removal purposes. 
         [0036]    Lip  122  of each guard  94  overlaps half of the nose  54  of one module  28  and half of the nose  54  of the next adjacent module  28 . Bolts  166  pass through holes  148  in lip  122  and holes  56  in nose  54  to thereby secure the front of each guard  94  to the adjacent modules  28 . Thus, each guard  94  is secured at its front to the modules  28  by bolts  166  and at its rear to the beam  12  by bolts  104 . 
         [0037]    While the rear ends of modules  28  are secured to beam  12  by carriage bolts  50 , guards  94  add further structural rigidity and support in a fore-and-aft sense to modules  28 . Due to the overlapping relationship of guards  94  with seams  44  of the modules, guards  94  also provide increased structural rigidity and support to modules  28  along the length of cutter bed  10 . Relative up and down movement between modules  28  is resisted by guards  94 . 
         [0038]    It will be noted that although the notches  138  of guards  94  are in alignment with seams  44  between modules  28 , the joints  162  between adjacent guards  94  are not in alignment with seams  44  or notches  138 . Consequently, there is no opportunity for trash and dirt to wedge into areas immediately in front of seams  44 , as would be the case if joints  162  were in forward alignment with the seams. This helps reduce the tendency for premature wear and weakening of the cutter bed in the area of seams  44  and notches  138 . Extraneous materials that may tend to collect in the vicinity of joints  162  appears to be readily handled by the knives in that area. 
         [0039]      FIG. 13  illustrates a second embodiment of the invention wherein the cutter modules are not mounted on a common support beam and instead rely on their interconnections with one another for mutual structural support. The series of cutter modules is thus self-supporting in this respect. 
         [0040]    Accordingly, the cutter module  228  and guard  294  of  FIG. 13  are identical to cutter module  28  and guard  94  of  FIGS. 1-12  except in the way guard  294  is attached to the rear of module  228 . In this respect it will be appreciated that guard  294  is slightly shorter than guard  94  in a fore-and-aft direction and has an upturned, rear margin  294   a  that bears against the rear faces of ears  248  of adjacent gear cases  230 . Each guard  294  overlaps and bridges adjacent modules  228  in the same manner as guards  94 , and screws  294   b  (only one being shown) secure rear margin  294   a  to ears  248  of adjacent modules  228  so as to reinforce and structurally tie adjacent modules together. The front end of each guard  294  is secured to a pair of adjacent modules  228  in the same manner as in the first embodiment. 
         [0041]    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.