Abstract:
A tillage apparatus includes a trip linkage selectively configured as a spring biased trip linkage, a spring toggle trip linkage, or a shear bolt trip linkage and mounted between a toolbar bracket and a shank member wherein the trip linkage is selected to allow shaft member to pivot upwardly responsive to variable excessive draft force.

Description:
FIELD OF INVENTION  
       [0001]    The present invention relates to farm implements and more particularly to a tillage implement enabling a ground tilling tool which encounters an obstacle to avoid damage by tripping a link between the tilling tool and a tool bar. In greater particularity the present invention relates to an apparatus and a method by which certain linkage members that connect a primary tillage tool to a toolbar can be substituted in such a way that the primary tillage tool, toolbar mount, and main arm, or any combinations thereof, remain standard components. The substituted linkage members do not affect the way the primary tillage tool works the ground but rather accentuates certain desirable features. 
       BACKGROUND 
       [0002]    Prior art designs dictate that should the operator require or prefer a change in the tripping mechanism of an agricultural implement, the toolbar mount and the shank must be replaced because there are major design differences between shear bolt tripping tillage tools and spring reset tillage tools. Reset-on-the-go tillage took using a spring biased mechanism are often preferred for ease of use, but have limitations. Shear bolt tillage tools often have high trip settings, but require more time to replace the shear bolt should the tillage tool hit an obstruction. 
         [0003]    Flexibility in trip mechanisms would allow for reduced inventory, higher part volumes and faster turnaround times at the factor. Operators would also realize greater benefits from their equipment. Trip mechanisms that utilize springs are inherently tied to spring pressure that can be difficult to adjust or different field conditions. By substituting a different trip mechanism, such as a shear bolt tillage tool, the actual force required for the tillage tool to trip can be economically increased to meet field demands with limited downtime. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    Referring to the drawings which are appended hereto and whit form a portion of this disclosure, it may be seen that: 
           [0005]      FIG. 1  is a side elevation view of a first selected tillage tool linkage; 
           [0006]      FIG. 2  is a side elevation view of a spring assisted tillage tool linkage in accordance with this invention; 
           [0007]      FIG. 3  is a side elevation view of a shear pin protected tillage tool linkage in accordance with this invention; 
           [0008]      FIG. 4  is a side elevation of a second embodiment of a of a spring assisted tillage tool linkage; and, 
           [0009]      FIG. 5  is a side elevation of a third embodiment of a of a spring assisted tillage tool linkage. 
       
    
    
     DETAILED DESCRIPTION  
       [0010]    Referring to the Figures for a fuller understanding of the invention, it may be seen that  FIG. 1  depicts a first selected trip linkage. A primary tillage component is shown at  10  and includes a shank member  11  and a plow or other primary tillage implement  12 . A toolbar mount or bracket  20  is conventionally included to connect to a toolbar using V bolt  21 . The bracket  20  is connected to the shank member  11  by a main arm  30  which is pivotally mounted to the bracket  20  and the shank member  11 . Also pivotally mounted to the bracket  20  is a front trip link  5  which is hindgedly mounted to a rear trip link  14  which is pivotally connected to shank member  11  at connection  32 . A spring reset mechanism is provided at  16  intermediate main arm  30  and the hinged connection of front and rear trip links  15  and  14 . As the primary tillage tool is pulled through the ground it may hit an obstruction, such as a stamp or large rock. If this occurs, the force front the collision will cause rear trip link  14  and front trip link  15  to open upward and overcome the spring pressure from spring reset mechanism  16 . The primary tillage tool  12  will then raise out of the ground, reset to the original configuration, penetrate the ground, and return to the operational depth while the implement is being pulled forward. 
         [0011]    A first embodiment of substitute linkage members is shown in  FIG. 2 . The substitute linkage members in this embodiment are more fully explained in U.S. Pat. No. 5,072,793 which is incorporated herein by reference. Note that in this embodiment front and rear trip links  15  and  14  as well as biasing spring  16  have been eliminated. A shank strap  19  is connected to the main arm at the same location biasing spring  16  would have been connected. Shank strap  19  is connected to the shank member at the pivot connection where rear trip link  14  would have been connected. Shank strap  19  may also be connected at an alternative location on the shank member  11  as shown in  FIG. 4 . In the embodiment of  FIG. 4 , the shank strap  19  may be engaged with a notch on shank member  11  or be pinned to shank member  11 . In same instances, it may be desirable to eliminate the shank strap  19  and simply add a removable locking pin  45  as shown in  FIG. 5 . Locking pin  45  would pass through main arm  30  and shank member  11  to hold them in fixed angular relation. The replaceable trip assembly of this embodiment includes relatively rigid toggle member  38  and relatively resilient spring toggle member  37 . Rigid toggle member  38  is preferably pivotally pinned at joint  32  to shank member  11  of plow  12 , while spring toggle member  37  is pinned at second joint  34  to bracket  20 , spring toggle member  37  is pinned to rigid toggle member  38  at third joint  36 . The two toggle members  37  and  38  normally maintain plow  12  in plowing position. 
         [0012]    A line extending between first point  32  and second point  34  is vertically above third point  36  by is small distance, defined as an undercenter dimension, when plow  12  is in plowing position. If plow  12  encounters a stone or other obstruction, an obstruction force F is transmitted to plow  12 . This force creates a column force inwardly from both first point  32  and second point  34 , flexing spring toggle member  37  upwardly against a fulcrum  39  carried on rigid toggle member  38 , which tends to bend third joint  36  upwardly. If third point  36  moves upwardly through the under-center dimension such that it crosses the line between first joint  32  and second joint  34 , the assembly trips. Plow  12  then moves from plowing position to a blipped position removed from the ground. The three required to move third joint  36  to cross the line is defined as a trip load. This force is caused by the primary tillage tool hitting an obstruction in the ground. Once the hinge point rises above this line of force the primary tillage tool is free rise out of the ground to clear the obstruction. In this iteration the tool bar would have to be lifted to allow the shank to reset itself. Once the tillage tool resets itself, it can be lowered so that it reengages the ground and operation can resume. 
         [0013]    A second embodiment of the substitute linkage is shown in  FIG. 3  where, rear trip link  14  and front trip link  15  remain in place, although possibly modified, and spring reset mechanism  6  has been removed. Again, a shank strap  19  may be connected to the main arm at the same location biasing spring  16  would have been connected. Shank strap  19  is connected to the shank member at the pivot connection where rear trip link  14  is also connected. Connecting dogs  40  and  41  have been added to the assembly at the connection of front trip link  15  no bracket  20 . Dogs  40  and  41  with a bolt  44  form a shear joint that prevents front trip link  15  from rotating about bracket  20 . If the primary tillage tool  12  hits an obstruction rear trip link  14  and front trip link  15  will try to break upward as in the embodiment shown in  FIG. 1 , however in this embodiment they must overcome the shear point of the bolt or pin  44  connecting dogs  40  and  41 . Once the bolt  44  shears front trip link  15  is free to rotate upward about the connection to the bracket and the primary tillage tool  12  is free to rise and clear the obstruction. To reset the primary tillage tool  12 , the toolbar must be raised by the tractor and the shear bolt  44  must be replaced. The tool is the ready for continued use. 
         [0014]    It may be seen from the foregoing that the intent of the present invention is to provide a base tillage tool comprising a toolbar bracket, main arm and shank member that can accommodate multiple trip mechanisms to enable the farmer to efficiently utilize his equipment in variable field conditions such as moving from a field that has been under cultivation for many years to a new ground field that has just been cleared to cultivation to a field with substantial hardpan. Each type field may have soil characteristics that dictate the type trip mechanism that will be preferred and the present invention allows the selection to be made with minimal investment in equipment and minimal down time. 
         [0015]    While in the foregoing specification this invention has been described in relation to certain embodiments thereof, and many details have been put forth for the purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.