Abstract:
A simplified, low component harrow attachment includes several clevis-like mounting castings pivotally connected between two identical flat side sheets. A link which pivots the ranks in unison is pinned to the legs of the mounting castings between the sheets by free-floating pins captured between the sheets. The castings can pivot to a retracted position and be secured by a pin for increased clearance between the teeth and the ground during transport. The rear mounting casting has a longer clevis structure than the remainder of the castings and serves as a tine depth stop when a stop pin is inserted through apertures in the sheets.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to agricultural tillage implements, and more specifically to adjustable harrow assemblies.  
         BACKGROUND OF THE INVENTION  
         [0002]    Toothed harrow attachments are commonly mounted behind tillage implements such as field cultivators to level soil and help break up large clods. Several ranks of teeth are supported from a drawbar arrangement, and for accommodating tooth adjustments of the aggressiveness of the harrow, the ranks often are pivotally connected to bracket members attached to drawbars. Such attachments include a relatively large number of components, including numerous nuts, bolts and washers which mount the ranks and connect angle adjusting links. Properly assembling the components and torquing the nuts for maintaining adjustability while eliminating excess looseness in the assembly is a difficult and time-consuming task. The numerous components require a lengthy assembly process and add significant manufacturing costs. Such harrows can also be difficult for the operator to adjust and maintain.  
           [0003]    A further problem with the conventional harrow design is providing adequate ground clearance during transport of the attachment. A limited amount of space for the rank-supporting structures and adjusting links often prevents pivoting of the teeth to a retracted position for increasing the clearance.  
           [0004]    On harrow attachments having adjustable down-pressure springs on the drawbars, providing a simple and reliable adjustment bolt lock has been a continuing source of difficulty. Conventional latch mechanisms wear heavily because of relative movement between the adjustment screw and the latch. Heavy vibration common in the assembly can also result in loss of desired down-pressure adjustment.  
         SUMMARY OF THE INVENTION  
         [0005]    It is therefore an object of the present invention to provide an improved harrow attachment for an agricultural implement. It is a further object to provide such an attachment which overcomes most or all of the aforementioned problems.  
           [0006]    It is another object of the invention to provide an improved harrow attachment having adjustable teeth. It is yet another object to provide such an attachment which has fewer components and is less costly and time-consuming to assemble and maintain than at least most previously available adjustable harrow attachments.  
           [0007]    It is still another object of the invention to provide an improved harrow attachment having adjustable teeth which can be adjusted to obtain various ground profiles and which can be pivoted to a transport position to increase ground clearance.  
           [0008]    It is yet another object of the invention to provide an improved harrow attachment having a simple and reliable down pressure adjustment lock.  
           [0009]    In accordance with the above objects, an improved harrow attachment includes several clevis-like mounting castings pivotally connected between two identical flat side sheets by a like number of bolt assemblies. A drag link which pivots the ranks in unison is pinned to the legs of the mounting casting between the sheets by free-floating pins captured between the sheets. The bolt and free-floating pin design eliminates numerous components and makes fabrication and maintenance less expensive and time-consuming. The design also allows the castings to pivot farther and the drag link to tuck and be pinned in a transport position for increased clearance between the teeth and the ground.  
           [0010]    The rear mounting casting has a longer clevis structure than the remainder of the castings and serves as a tine angle setting or aggressive stop when a stop pin is inserted through apertures in the plates. The ability to adjust tine angle allows different final soil profiles to be obtained. By increasing tine down-pressure and orienting the tines in a generally vertical position, tough large clods can be sized. Decreasing tine down-pressure and decreasing or flattening the tine angle facilitates high residue flow through the harrow without plugging or bunching.  
           [0011]    To retain the down-pressure spring adjustment in the desired position, a short section of apertured square tubing or a casting with a round inner surface and rectangular outer surface is placed over the threaded portion of the bolt. An aperture in the bolt is aligned with the apertures in the tubing or casting, and a spring pin is inserted. The tubing or casting, which is sandwiched between the sides of the spring support legs, prevents rotation of the bolt from the adjusted position. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a perspective view of a portion of a harrow attachment.  
         [0013]    [0013]FIG. 2. is an exploded view of a portion of the harrow attachment of FIG. 1.  
         [0014]    [0014]FIG. 3 is a perspective view, partially in section, showing of portion of the harrow attachment with the tine adjustment in the maximum depth working position.  
         [0015]    [0015]FIG. 4 is a view similar to FIG. 3 but showing the adjustment in the transport position.  
         [0016]    [0016]FIG. 5 is a perspective view of the down-pressure adjustment for the harrow attachment.  
         [0017]    [0017]FIG. 6 is an enlarged perspective view of a rank support casting for the harrow attachment. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]    Referring to FIG. 1, therein is shown a portion of a harrow  10  including a drawbar  12  having a forward end pivotally connected by a pin  14  with roll pins at each end to a support bracket  16 . The bracket  16  includes a mounting portion  18  adapted for securing against the aft face of an implement frame member (not shown), such as the rear transverse tubular frame member of a field cultivator.  
         [0019]    The bracket  16  extends upwardly to a spring support  20  having spaced side walls  22  for receiving the forward portion of a down-pressure spring assembly  24 . A spring bracket  28  extends upwardly from the drawbar  12  rearwardly of the pivot pin  14  and supports the aft end of the assembly  24 .  
         [0020]    An adjustable tine support assembly  30  is pivotally connected to the aft end of the drawbar  12  by a bolt or pivot pin assembly  32  extending though apertures  33 , and a bolt or pin  34  located forwardly of the pin  32  and passing through sets of apertures  34   a  or  34   b  in the drawbar  12  and a selected aperture  35  locks the assembly  30  in the desired angular position relative to the drawbar  12 . As shown in FIG. 1, three ranks of tines  41 ,  42  and  43  are carried by the adjustable tine support assembly  30 .  
         [0021]    The assembly  20  includes a pair of plates  50 , which preferably are planar and identical for ease of manufacture and assembly. An upper edge of each plate is generally straight, and a lower edge includes notch locations  51 ,  52  and  53  to accommodate pivoting of the ranks of tines  41 - 43  to a rearward tucked transport position. Tine support brackets  61 ,  62  and  63  are pivotally mounted between the plates  50  adjacent the lower edge by bolts  66  and bushings  68  (FIG. 2). The bolts  66  extend through apertures  67  near the lower edge of the plates and through the bushings  68 . The bolt and bushing combinations not only provide pivot surfaces for the support brackets but also acts to tie the lower portions of the two plates  50 , while the top portions of the plates  50  are spaced solidly by the aft end of the drawbar  12  and the bolts  32  and  34 . A tight joint is formed with the drawbar  12 , and structural strength is increased significantly over previous structures having looser joints so that fewer drawbars for a given width of harrow attachment are required.  
         [0022]    The brackets  61  and  62  are generally identical and are preferably fabricated as castings having a clevis area or pair of transversely spaced upright legs  70  connected to lower transversely extending apertured attaching flanges  72 . The rear support bracket  63  (FIG. 6) is similar in construction to the brackets  61  and  62  but includes longer upright legs  70 ′ which project radially from the pivot area beyond sets of apertures  76  which receive pin  78 . The pin  78  acts as a tine angle setting stop by limiting the pivoting of the brackets in the counter-clockwise direction as viewed in FIGS.  1 - 4 . The brackets  61 - 63  pivot clockwise until the legs hit the tine angle setting pin  78 . The tines freely rotate in the counter-clockwise direction to avoid tine damage if the harrow is backed up while the tines are contacting the ground. The pin  78  can also be used to secure the tines in a retracted transport position (FIG. 4) when placed behind the legs  70 ′ in the forwardmost aperture pair location  76   f.    
         [0023]    A flat connecting link  80  of preselected thickness is pivotally connected between the legs  70  and  70 ′ to constrain the brackets  61 - 63  for pivoting in unison about the bolts  66  and bushings  68 . The legs  70  and  70 ′ include apertures  84  with inwardly projecting bosses  86  which are transversely spaced a distance approximately equal to the preselected thickness of the link  80  to sandwich the link  80  and maintain it in generally an upright plane. A single cylindrical pin  88  of length approximately equal to the spacing of the outer walls of the legs  70  is inserted through each of the aperture pairs  84  and through a corresponding aperture in the link  80 . After assembly of the harrow  10 , the pins  88  float in the apertures  84  and are held in position by the inner walls of the plates  50  thereby reducing the amount of necessary hardware, assembly time, and maintenance. The compact arrangement of the link  80  within the bosses of the legs of the bracket clevis also provides a clean design and increases the angle through which brackets  61 - 63  can pivot and move to a transport location for increased ground clearance.  
         [0024]    The drawbar  12  and the bolt or pivot pin assembly  32  space the upper end of the plates  50 , and the bolts  66  and bushings  68  which pass though apertures  94  and bosses  96  on the bracket castings (FIG. 6) below the apertures  84  space the lower portions of the plates  50 . Nuts  98  threaded onto the ends of the bolts  66  secure the plates  50  against the ends of the bushings  68  and maintain the plates in generally a parallel relationship.  
         [0025]    Transversely extending tine bars  100  (FIG. 1) are bolted to the flanges  72  and support earthworking tools  102  such as spring tines or the like. The brackets  61 - 63  pivot in unison in the clockwise direction until the forward edges of the legs  70 ′ of the rear bracket  63  engage the pin  78 . By selecting a different set of apertures  76  and changing the location of the pin  78 , the angle and thus the aggressiveness and depth of operation of the tools  102  can be changed. If the working depth of the towing implement changes the height of the support bracket  16  relative to the ground changes for any reason, the pin  34  may be relocated relative to the apertures  35  and/or the apertures  34   a  and  34   b  to level the harrow  10 .  
         [0026]    The down pressure spring assembly  24  includes a spring  114  compressed between a pair of nuts  116  threaded onto a bolt or threaded rod  118 . A single jam nut or other retaining structure may also be used in place of the two nuts  116 . The forward end of the rod  118  is threaded through a turnbuckle  120 , and a nut to the rod  118  or other enlarged end  122  at the opposite end of the rod  118  retains the assembly  24  in position and provides a positive down stop limit for the harrow  10 . By adjusting the rod  118  relative to the turnbuckle  120 , down stop limit can be changed. Because of the extreme vibrations in the harrow  10 , a positive anti-rotation assembly  130  is provided for the forward end of the rod  118  to secure the assembly in the position for the desired down-pressure. The assembly  130  includes a short section of square tubing or apertured casting  132  which slides over the forward end of the rod  118 . The square tubing or casting  132  and the rod  118  have bores which can be aligned, and a spring pin  136  is inserted through the aligned bores. The cross-sectional width of the square tubing or casting  132  assures that the device will slide between the spaced side walls  22  of the bracket  16  but will not rotate between the walls. Therefore, when the spring pin  136  is inserted, the rod  118  cannot rotate.  
         [0027]    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.