Abstract:
An agricultural implement has a marker assembly that is pivotable in a generally rearward direction when the marker assembly collides with a relatively massive field obstruction. The interconnection of the marker assembly to a central frame of the implement allows the aforementioned pivoting to reduce damage to the central frame and/or the marker assembly during such collisions.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the benefit of U.S. Ser. No. 61/151,386 filed Feb. 10, 2009. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates generally to agricultural implements and, more particularly, to a seeder having a breakaway marker. 
         [0003]    Agricultural seeders, which are commonly used to deposit seed, fertilizer, and granular chemicals onto a farm field, generally consist of a towable frame that supports one or more rows of seed units. Seed or other granular product is typically metered to the seed units which in turn deposit the product onto the farm field. The seeder will often include furrowing opening devices, such as coulters, knives, shanks, and the like that cut a furrow into the farm field immediately ahead of the seed units so that the granular product is deposited into a furrow rather than simply atop the farm field. A trailing packer will then pack the furrow to improve germination and/or fertilization. 
         [0004]    Agricultural seeders are also commonly outfitted with a pair of marker assemblies. Each marker assembly will generally include a marker frame which carries a marking disc. A seeder will typically have a marker frame extending laterally on opposite sides of the seeder, and the marker frames can be independently raised and lowered by a respective lift assembly, such as a hydraulic cylinder. The marking disc is designed to cut a furrow into the farm field which serves as a marker as to the position of the seeder as the field was passed. Thus, during a subsequent pass of the farm field, the operator can position the seeder so that the next pass is properly aligned with the previous seeding pass to prevent overseeding of a previously seeded area or to prevent undesirable gaps in the seeded rows. Improper uniformity in spacing of the rows as well as distribution of the seed can negatively impact crop yields. 
         [0005]    Occasionally, as the seeder is being towed by the tractor across the farm field, the marker frame may collide with an obstacle in the farm field, such as an unseen rock. To reduce the impact of such collisions, the marker frame must be built in a manner and with materials that are capable of withstanding the impact with such objects without causing fracture or other damage to the marker frame. Moreover, since the marker frame is coupled to the main frame of the seeder, the composition of the marker frame must be such that collision of the marker frame with an obstruction does not negatively impact the main towable frame of the seeder. This typically results in relatively heavy, bulky, and ultimately costly marker frames that can significantly impact the overall weight and size of the seeder as well as its cost. 
         [0006]    Therefore, there is a need for a marker assembly better suited to handle collisions with field obstructions. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention is directed to an agricultural implement having a marker assembly that is pivotable in a generally rearward direction when the marker assembly collides with a relatively massive field obstruction. The interconnection of the marker assembly to a central frame of the implement allows the aforementioned pivoting to reduce damage to the central frame and/or the marker assembly during such collisions. 
         [0008]    In one embodiment, the marker assembly is connected to the central frame of the implement by a two-part joint assembly. The joint assembly has a first portion that is connected to the central frame of the implement and a second portion that is connected to the marker assembly. The two joint portions are connected by a vertical pivot pin and a tension bolt. When an obstruction of sufficient mass is encountered, the tension bolt will fail thereby allowing the second joint portion, and thus the marker assembly, to pivot rearwardly relative to the first joint portion about the pivoting axis of the pivot pin. The present invention therefore allows the marker assembly to clear the obstruction without damaging the marker assembly or the central frame of the implement. 
         [0009]    It is therefore an object of the invention to provide a marker assembly capable of pivoting in a rearward direction when colliding with field obstructions. 
         [0010]    It is another object of the invention to limit rearward pivoting of the marker assembly to those collisions when significant damage would result to the marker assembly and/or central frame of the implement if rearward pivoting was not permitted. 
         [0011]    Other objects, features, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0012]    Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout. 
           [0013]    In the drawings: 
           [0014]      FIG. 1  is an isometric view of a marker assembly according to one embodiment of the invention; 
           [0015]      FIG. 2  is a side isometric view of a mounting end of the marker assembly shown in  FIG. 1 ; 
           [0016]      FIG. 3  is a rear top isometric view of the mounting end of the marker assembly shown in  FIGS. 1 and 2 ; 
           [0017]      FIG. 3A  is a top plan view of the marker assembly shown in a breakaway position according to one aspect of the invention; 
           [0018]      FIG. 4  is a top isometric view of the interconnection of the inner frame section and central frame section of the marker assembly of  FIG. 1 ; 
           [0019]      FIG. 5  is a side isometric view of that shown in  FIG. 4 ; 
           [0020]      FIG. 6  is a side isometric view of the interconnection of the central frame section, a caster wheel assembly, and an outer frame section of the marker assembly of  FIG. 1 ; 
           [0021]      FIG. 7  is a top isometric view of that shown in  FIG. 6 ; 
           [0022]      FIG. 8  is an view of the outer frame section of the marker assembly of  FIG. 1 ; 
           [0023]      FIG. 9  is a rear isometric view of that shown in  FIG. 6 ; and 
           [0024]      FIG. 10  is an isometric view of a spring link for use with the marker assembly of  FIG. 1  according to one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    The present invention is directed to a marker assembly  10 , shown in  FIG. 1  in a partially deployed position, for use with an agricultural implement, such as a seeder (not shown). The marker assembly is generally comprised of a multi-linked frame  12  that includes a mounting assembly  14 , an inner frame section  16 , a central frame section  18 , a caster wheel assembly  20 , and an outer frame section  22 . Each of these will be described in greater detail below. As will become apparent from the following description, the marker assembly  10  is designed to be folded into a transport or stow position and may be extended to a working position.  FIG. 1  shows the marker assembly in a pre-deployment position in which the linkage sections  16 ,  18 , and  22  are partially extended. The marker assembly  10  is generally supported by its connection to the frame (not shown) of the agricultural implement and a wheel  24 , which is free to caster as will be described. The outer frame section  22  carries a marking disc  26  designed to cut a marking furrow into the soil as the agricultural implement is being towed with the marking disc  26  in a ground engaging position. As will be described more fully below, the distance of the marking disc  26  from the agricultural implement may be varied to provide a user some flexibility in establishing the spacing of the marking furrow from the agricultural implement. 
         [0026]    The inner linkage section  16  is generally defined by a pair of spaced but parallel frame tubes  28 ,  30  connected at one end by a cross tube  32  connected at an opposite end by a cross tube  34 . To provide additional stability for the inner frame section, tubes  28 ,  30  are connected to one another by a series of intersecting plates, generally referenced  36 . It is understood that other stability arrangements other than those shown in the figures may be used. 
         [0027]    The central frame section  18  also includes a pair of elongate tubes  38 ,  40  interconnected by a pair of cross tubes  42 ,  44 . A series of intersecting members  46  also extend between the tubes  38 ,  40  to provide additional structural integrity to the central frame section  18 . 
         [0028]    The outer frame section  22  includes a pair of elongate tubes  48 ,  50  that are angled toward one another and are interconnected at one end by a cross tube  52  and another end by a retainer  54 . As will be described more fully below, the retainer  54  interconnects tubes  48 ,  50  to a telescoping tube  56 , to which marking disk  26  is connected. 
         [0029]    The aforementioned linkage sections will be described in greater detail below with reference to  FIGS. 2 through 10 . 
         [0030]      FIGS. 2 and 3  are partial front top perspective and partial rear top isometric views of the marker assembly  10  and, more particularly, the mounting assembly  14  and the connection of the inner frame section  16  to the mounting assembly  14 . The mounting assembly  14  includes a knuckle  58  comprised of an inner knuckle member  60  and an outer knuckle member  62 . The inner knuckle member  60  is mountable to the frame of the agricultural implement in a conventional manner and the outer knuckle member  62  is connected to the inner knuckle member  60  by a tension bolt  64  and a vertically oriented pin  66 . The tubes  28 ,  30  are secured to the outer knuckle member  62  by a shaft  68  that is passed through openings (not numbered) in the tubes  28 ,  30  and through the cross tube  32 . The shaft  68  fits within a boss  70  at the side of the tube  28  and a cross bolt  72  is passed through openings in the shaft  68  and the boss  70  to secure the shaft  68  to the boss  70  and thus to the tube  28 . 
         [0031]    As shown particularly in  FIG. 3 , the outer knuckle member  62  has a top ear  74  and a bottom ear  75  that fit over lateral plates  76 ,  78  of the inner knuckle member  60 . The lateral plates  76 ,  78  and the ears have openings (not numbered) that when aligned allow for vertical pivot pin  66  to be dropped into a passage (not shown) formed in the inner knuckle member  60 . The vertical pivot  66  is secured to the inner knuckle member  60  by bolt  80 . The connection of the inner and outer knuckle members  60 ,  62  allows the outer knuckle member  62  to pivot relative to inner knuckle member  60  in a generally rearward direction and about a vertical axis defined by the vertical pin  66 , as shown in  FIG. 3A . 
         [0032]    That is, the knuckle  58  is designed so that the outer knuckle member  62 , and the inner frame section  16  connected thereto, can rotate in a rearward direction (opposite the direction of travel of the implement). Such rotation is permitted when the tension bolt  64  breaks. The tension bolt  64  is carried by a bolt housing  82  that is defined by an outer housing portion  84  and an inner housing portion  86 . The outer housing portion  84  extends from a side of the outer knuckle member  62  and the inner housing portion  86  extends from a side of the inner knuckle member  60 . Other than the pivot pin connection described above, the only other connection of the inner and outer knuckle members is by the tension bolt  64  that connects the inner and outer housing portions. When the tension bolt breaks  64 , those housing portions become separated, which allows the inner linkage  16 , as well as, the other linkages, to pivot rearwardly. The tension bolt  64  is designed to fail, e.g., break, when the deployed marker assembly  10  encounters a field obstruction with sufficient force to overcome the integrity, e.g., tensile force, of the tension bolt  64 . When such an obstruction is encountered, the implement will continue to move in a forward direction and will try to pull the marker assembly “through” the obstruction. This can lead to damage in the implement and the marker assembly. As such, the present invention allows the marker assembly  10  to pivot rearward so as to clear the obstruction, if the obstruction is massive enough to cause failure of the tension bolt  64 . 
         [0033]    As noted above, the marker assembly  10  is designed to be folded into a transport or stow position and may then be extended from such a position to a working position. This aforementioned movement is controlled by a pair of actuators  88 ,  90 , e.g., cylinders. Actuator  88  is designed to move the marker assembly  10  from an upright retracted position to a horizontal stow position for transport and storage. Actuator  90  on the other hand is designed to extend and retract the marker assembly  10 . The actuator  90  is connected to the upper link  92 , which in turn is connected to cross tube  34  of the inner frame section. 
         [0034]    The inner frame section  16  also includes a parallel link  94  that is connected at one end to the outer knuckle member  62  in a conventional manner and is connected at the opposite end to a bridge link  96 , as shown in  FIG. 4 , which will be described more fully below. As will be also be described more fully below, when the actuator  90  is extended, the parallel link  92  is also extended which, in effect, causes a lowering of the inner frame section  16 . Because of counterpart parallel links in the central frame section  18 , extension of the actuator  90  also causes extension and lowering of the central frame section  18 , which in turn causes a lowering of the outer frame section  22 . Retraction of the cylinder  90  results in the linkages being retracted to an upright retracted position. 
         [0035]    Referring again to  FIGS. 2 and 3 , the marker assembly  10  also includes a float link  98  that connects the outer knuckle member  62  and the cylinder  90 . The float link  98  is bolted to a pair of arms  100 ,  102  formed with and extending upwardly from the outer knuckle member  62 . The bolt  104  effectively forms a pivot which allows the float link  98  to rotate to accommodate the motion of the marker assembly  10  in response to ground contours. A bottom surface  105  of the float link  98  limits how far the float link  98  may pivot and optional bumpers  106 ,  108  mounted to cross tube  32  may be used to limit downward movement of the float link  98 . In a preferred embodiment, the float link  98  allows  30  degrees of vertical movement in response to surface contours with preferably  15  degrees of lift and  15  degrees of lower relative to a neutral position. 
         [0036]    The inner frame section  16  also has a rigid link  110  that is connected at one end to the outer knuckle member  62  in a conventional manner and is connected at the opposite end to a lever arm  112 , as also shown in  FIG. 4 . The lever arm  112  forms part of a cam and roller assembly  114  that further includes a cam  116  and a cam roller  118 . The cam  116  is interconnected to the cross tube  34  and the cam roller  118 . The lever arm  112  is also connected to a center link  119  of the central frame section  18 . 
         [0037]    During deployment of the marker assembly  10 , there is a point at which the wheel  24  will engage the surface and move outwards away from the implement. The point where the wheel  24  engages the surface is set by the rigid link  110  and the cam assembly  114 . That is, the rigid link  110  pulls down on the lever arm  112  causing the central frame section  18  to move away from the inner frame section  16 . The amount the central frame section  18  moves away is determined by the profile of the cam  116 . The cam roller  118  follows the cam profile changing the distance the lever arm  112  is away from the inner section  16 . This variation in distance provides control of the distance at which the wheel  24  engages the soil surface. Moreover, the cam assembly  114  provides gradual increases in the loading of the rigid link  110 . 
         [0038]    Referring to  FIGS. 4 through 6 , the central frame section  18  includes tubes  38 ,  40  which are connected to one another by cross tube  42 . Tubes  28  and  38  are interconnected to one another by end plates  120  and  122 , respectively. Similarly, tubes  30  and  40  are interconnected to one another by end plates  124  and  126 , respectively. The end plates are connected to a common pivot rod  128  in a manner that allows the inner frame section  16  and the central frame section  18  to pivot with respect to one another when the marker assembly  10  is being deployed or retracted. 
         [0039]    The central frame section  18  also includes a parallel link  130  that is connected to parallel link  94  by bridge link  96 . One skilled in the art will appreciate that link  130  reacts to movement of parallel link  94  during deployment and retraction of the marker assembly. 
         [0040]    The parallel link  130  is also connected to a bridge link  132 , as shown in  FIG. 6 . 
         [0041]    Similarly, tubes  38  and  40  have plates  134  and  136  that are connected to cross tube  44  and to respective tubes  138  and  140  of the wheel mount assembly  20 . The bridge link  132  is connected to the outer frame section  22  by a spring linkage  142 , which will be described more fully with respect to  FIGS. 9 and 10 . 
         [0042]    Wheel  24  is mounted to a wheel mount  144  that is formed with, or otherwise connected to, tube  138 . The wheel  24  has an axle  146  to which an offset arm  148  is connected. The offset arm  148  is in turn connected to a pivot arm  150  that is secured to the wheel mount  144  by a vertical pivot pin  152 . The pivot arm  150  is mounted to the pivot pin  152  in a manner that allows the pivot arm  150  to caster freely about the vertical axis defined by the pivot pin  152 . This movement of the pivot arm  150  in turn allows the wheel  24  to caster. This is particularly advantageous when the wheel  24  encounters an obstruction to avoid damage to wheel  24  or other components of the marker assembly  10 . 
         [0043]    Additionally, during deployment of the marker assembly  10 , as noted above, the wheel  24  engages the soil surface before the marker assembly  10  is fully deployed. The marker assembly  10  is deployed in a lateral direction, i.e., in a direction perpendicular to the direction of travel of the implement. A conventional wheel is only permitted to rotate along a rotational axis that is perpendicular to the travel direction of the implement and thus during deployment, the wheel is pushed along the soil surface, which can cause damage to the wheel or other components of the marker assembly  10 . The present invention, however, allows the wheel  24  to caster and thus, during deployment and when the wheel  24  engages the surface, the wheel  24  can rotate around an axis that is parallel to the direction of travel of the implement to effectively walk the marker assembly to the deployed position. This removes some of the loading on the mount  14  during deployment of the marker assembly  10 . Similarly, during retraction of the marker assembly, the wheel  24  can caster to a position to rotate toward the agricultural implement to provide support for the outer and central frame sections until the marker assembly  10  is lifted off the ground by actuator  88 . 
         [0044]    Referring now to  FIG. 8 , the outer frame section  22  includes tubes  48 ,  50  and a telescoping link  56 . Retainer  54  includes first and section flanges  154  and  156  to which tubes  48  and  50  are connected. Flange  154  has an opening  158  through which a center tube  160  extends. The center tube  160  is connected to cross tube  52 ,  FIG. 6 , by a connecting element  162 ,  FIG. 7 , and is connected to flange  156 . Flange  156  has an opening (not numbered) through which link  56  may be inserted. The retainer  54  also has a U-bolt  164  that is aligned with the opening in the flange  156  so that the link  56  is passed through the opening (not numbered) defined by the U-bolt  164 . Fasteners  166 ,  168  may be tightened to draw the U-bolt  164  into engagement with the link  56  and secure the link  56  to the flange  156 . Marking wheel  26  is connected to a distal end of the link  56 . 
         [0045]    The construction of the link  56  and retainer  54  allows a user to manually set the point where the link  56  is locked in position. Changing the position where the link  56  is secured to the retainer  54  changes the distance the wheel  26  is from the tubes  48 ,  50  and thus from the agricultural implement. 
         [0046]    Referring now to  FIGS. 9 and 10 , as mentioned above, a spring link  142  interconnects the central frame section  18  and the outer frame section  22 . The spring linkage  142  is generally comprised of a rod end  170 , catch nuts  172 , a compression spring  174  contained within a spring housing  176 , compression washers  178 , and a cylinder end  180 . As shown in  FIG. 9 , the cylinder end  180  is connected to tube  40  by a connector  182  and the rod end  140  is connected to the outer section linkage  22  by a bracket  184 . 
         [0047]    The spring  174  is retained by washers  178  within housing  176 . A linkage rod  186  passes through the housing  176  and has nuts  172  that are sized to catch the washers  178 . If the linkage is compressed or extended, the catch nuts  172  press up against the washers  178 , which results in compression of the spring  174 . By compressing the spring, a force is applied in the opposite direction as the momentum in the marker assembly during deployment, thereby resulting in a reduction in the momentum in the marker assembly during deployment. It will therefore be appreciated that the spring link  142  allows for rapid deployment of the marker assembly without compromising the outer frame section&#39;s ability to follow ground contours. 
         [0048]    Additionally, while the marker assembly has been shown and described as being configured to pivot rearwardly at mounting assembly  14 , it is understood that the marker assembly could be configured to pivot at other points along its length, such as approximate the marking disc  26 . 
         [0049]    Many changes and modifications could be made to the invention without departing from the spirit thereof The scope of these changes will become apparent from the appended claims.