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CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the filing benefits of U.S. provisional application Ser. No. 62/355,461, filed Jun. 28, 2016, which is hereby incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to plows that attach to a vehicle, such as a skid steer or the like, and are operable to move snow or other materials. 
       BACKGROUND OF THE INVENTION 
       [0003]    It is known to provide a plow at a vehicle. It is also known to provide adjustable wings at one or both ends of a main plow blade, in order to adjust the length of the plow. Such wings are movably disposed at the ends of the main plow blade and are individually controlled to provide the desired plow configuration. In order to control the wings, additional hydraulic circuits and electronic controls are needed at the plow assembly with corresponding user controls in the vehicle. In some cases, the wings are fixedly or non-adjustably attached at the ends of the main plow, and include struts or other attachments at the front of the main plow to retain the wings. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention provides a plow assembly having plow wings that are non-adjustably attached at the ends of a main plow moldboard. The wings are attached via elastomeric or resilient elements that allow for the wings to be pivoted or urged or forced inward or outward, such as in response to impact with an object during plowing. The resilient attachment elements allow the wings to absorb the impact and return the wings to the normal position generally normal to the main plow. The attachment means or attachment assemblies are disposed entirely rearward of the curved plowing front surface of the center plow or moldboard, so as to not interfere with the curved plowing surface to provide enhanced plowing of snow or other materials by the center plow and plow assembly. 
         [0005]    According to an aspect of the present invention, a plow assembly comprises a mounting structure configured to mount at a vehicle, and a center or main plow pivotally attached at the mounting structure. A plow wing is mounted at an end of the center plow via a first attachment assembly and a second attachment assembly (with the plow assembly preferably including a plow wing mounted at each end of the center plow), with each of the first and second attachment assemblies comprising an elongated attachment element (such as a bolt or rod or the like) and a biasing element (such as a resilient compressible and/or stretchable element). The elongated attachment element attaches a respective rear portion of the plow wing at the center plow, and the biasing element allows for movement of the attachment element relative to the center plow to allow for pivotal movement of the plow wing relative to the center plow (such as responsive to an impact of the plow wing with an object during plowing). The biasing element limits such pivotal movement of the plow wing and biases the plow wing towards a neutral or non-angled state, where the plow wing is generally normal to the center plow. 
         [0006]    The attachment element extends through a fixed portion of the center plow and further through the biasing element, such that outward movement of the attachment element (when the plow wing pivots) compresses the biasing element at the fixed portion of the center plow. The first attachment assembly may be disposed forward of the second attachment assembly and at a level above the second attachment assembly. When the plow wing pivots inwardly relative to the center plow, the biasing element of the second attachment assembly compresses more than the biasing element of the first attachment assembly, and when the plow wing pivots outwardly relative to the center plow, the biasing element of the first attachment assembly compresses more than the biasing element of the second attachment assembly. 
         [0007]    Optionally, the elongated attachment element of the first attachment assembly may be received through an arcuate slot of the plow wing and the elongated attachment element of the second attachment assembly is received through a circular aperture of the plow wing, such that the plow wing is pivotable about a generally horizontal longitudinal axis of the elongated attachment element of the second attachment assembly and thus can pivot between a lowered position and a raised position. 
         [0008]    Therefore, the present invention provides a plow assembly having plow wings that are attached at the ends of the center plow and pivotable or movable responsive to impact with an object. The plow assembly and plow wings are configured to allow inward or outward pivotal movement of the plow wings, whereby the attachment assemblies bias the plow wings toward their straight configuration, whereby, after impact with an object, the plow wing is returned to its normal state where it is generally normal to the main plow. Also, the attachment assemblies are located entirely rearward of the main plow moldboard, and thus do not interfere with the curved plowing surface of the moldboard. By eliminating or avoiding use of struts or the like that extend forward of the center plow to support the forward end region of the plow wing, the attaching assemblies of the present invention significantly improves the rolling motion of snow upward along the center plow during plowing of snow (or other material). Thus, the plow wings and attachment assemblies of the present invention allow for controlled limited pivoting of the plow wings (such as when one of the plow wings impacts an object during plowing) while allowing the curved moldboard to plow the snow or other material in an efficient and effective manner (without struts or other elements disposed at the moldboard to retain the plow wings at the moldboard). 
         [0009]    These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective view of a plow assembly in accordance with the present invention, shown with the wings in their normal position generally normal to the main plow; 
           [0011]      FIG. 2  is a rear perspective view of the plow assembly of  FIG. 1 ; 
           [0012]      FIG. 3  is a front plan view of the plow assembly of  FIG. 1 ; 
           [0013]      FIG. 4  is a side elevation of the plow assembly of  FIG. 1 ; 
           [0014]      FIG. 5  is a top plan view of the plow assembly of  FIG. 1 ; 
           [0015]      FIG. 6  is a rear plan view of the plow assembly of  FIG. 1 ; 
           [0016]      FIG. 7  is an enlarged rear perspective view of the plow assembly of  FIG. 1 ; 
           [0017]      FIG. 8  is a partial rear perspective view of the plow assembly of the present invention, shown with the plow wing compressed and angled inward; 
           [0018]      FIG. 9  is a top plan view of the plow assembly of  FIG. 8 ; 
           [0019]      FIG. 10  is a rear plan view of the plow assembly of  FIG. 8 ; 
           [0020]      FIG. 11  is a partial rear perspective view of the plow assembly of the present invention, shown with the plow wing angled outward; 
           [0021]      FIG. 12  is a top plan view of the plow assembly of  FIG. 11 ; 
           [0022]      FIG. 13  is a rear plan view of the plow assembly of  FIG. 11 ; 
           [0023]      FIG. 14  is a front perspective view of the plow assembly of the present invention, shown with the plow wings angled upward; 
           [0024]      FIG. 15  is a rear perspective view of the plow assembly of  FIG. 14 ; and 
           [0025]      FIG. 16  is a side elevation of the plow assembly of  FIG. 14 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    Referring now to the drawings and the illustrative embodiments depicted therein, a plow assembly  10  is configured to be mounted to a vehicle (not shown), such as a skid steer or pickup truck or other movable vehicle or the like, via a support  12 , such as an A-frame support or the like ( FIGS. 1-6 ). The plow assembly  10  includes a main or center plow  14  that is mounted at the support  12  (and may be pivotable side to side about a generally vertical pivot axis, such as via actuation of a respective one of two actuators or hydraulic cylinders or the like). Plow assembly  10  includes plow wings  16  mounted at opposite ends of the center plow  14 . The plow wings  16  are movably attached at the plow  14  via a pair of attachment assemblies  18 ,  20 , which hold the plow wings in a position generally normal to the plow  14  and which allow the plow wings to pivot inward or outward relative to the center plow (such as upon impact with an object during plowing), as discussed below. 
         [0027]    Each of the plow wings  16  comprises a generally flat metal plate  16   a  that is attached at its rear portion to the center plow  14  via the attachment assemblies  18 ,  20 . Each of the plow wings  16  may also include a lower edge element  22  attached at the bottom of the flat metal plate  16   a  to provide additional strength to the plow wing as it moves along the ground. In the illustrated embodiment, the plow wings are pivotally attached to the center plow via the lower attachment assembly  20 , while the upper attachment assembly  18  is received in an arcuate slot  16   b  of the plate  16   a . Such a mounting configuration allows for the plow wing to pivot about the generally horizontal longitudinal axis of the lower attachment assembly  20 , so as to allow the plow wing to pivot relative to the main plow  14  from a lowered position ( FIGS. 1-7 ) to an upward position (see  FIGS. 14-16 ), such as when the plow wing impacts an object during plowing. 
         [0028]    In the illustrated embodiment, the wing attachment assemblies  18 ,  20  comprise elongated bolts or fasteners or elements  18   a ,  20   a  (such as threaded bolts), which are received through the respective plow wing (such as through the slot  16   b  or through a lower hole or aperture) and through a flange  14   a  at the end of the main plow (and rearward of the front curved plowing surface of the main plow) and through a respective bracket  18   b ,  20   b  at the rear of the main plow  14 . The bolts  18   a ,  20   a  are further received through a resilient element or biasing element or bushing  18   c ,  20   c  disposed between the bracket  18   b ,  20   b  and a washer  18   d ,  20   d , with a nut or fastener  18   e ,  20   e  threadedly fastening or securing to the bolt  18   a ,  20   a  at the washer, so as to retain the bolt  18   a ,  20   a  and resilient element  18   c ,  20   c  at the bracket  18   b ,  20   b  of the plow  14 . 
         [0029]    The attachment assemblies  18 ,  20  retain the plow wing  16  at the side or end of the main plow  14 , and allow for limited pivoting of the plow wing  16  relative to the main plow  14 . The brackets  18   b ,  20   b  at the rear of the center plow  14  are fixed, such that, when the bolt  18   a ,  20   a  is pulled outwardly from the flange  14   a , the fastener  18   e ,  20   e  and washer  18   d ,  20   d  are pulled towards the bracket  18   b ,  20   b  to compress the resilient element  18   c ,  20   c . The resilient or biasing elements  18   c ,  20   c  compress responsive to pivoting of the plow wing relative to the main plow, and are biased toward their initial state or form, such that they urge and bias the plow wing  16  towards its neutral state. However, when the plow wing impacts an object that imparts an inward or outward force at the plow wing, the biasing elements  18   c ,  20   c  compress to allow for pivoting of the plow wing relative to the main plow. 
         [0030]    For example, and such as can be seen with reference to  FIGS. 8-10 , when the plow wing is pushed or forced inwardly (such as when the plow wing strikes an object at its outer side), the biasing element  20   c  of the lower attachment assembly  20  (which is rearward of the upper attachment element  18 , as can be seen in  FIGS. 4 and 9 ) compresses between the washer and the bracket as the bolt  20   a  is pulled outward from the flange  14   a  of the main plow  14 . As best shown in  FIG. 9 , the biasing element  18   c  of the upper attachment assembly  18  (which is forward of the lower attachment element  20 ), may slightly compress as the bolt  18   a  may also be slightly pulled from the flange  14   a , depending on where the forward most point of contact is between the plow wing and the main plow. In other words, if the upper attachment element  18  is generally at the forward most point of contact, then the plow wing may pivot at that point and thus only slightly pull the bolt  18   a  outward and thus only slightly compress the biasing element  18   c , but if the plow wing contacts the main plow substantially forward of the upper attachment assembly  18 , then both bolts  18   a ,  20   a  may be pulled outward and both biasing elements  18   c ,  20   c  may be compressed (with the rearward biasing element being compressed more than the forward biasing element). 
         [0031]    Also, for example, and such as can be seen with reference to  FIGS. 11-13 , when the plow wing is pushed or forced outwardly (such as when the plow wing strikes an object at its inner side), the biasing element  18   c  of the upper attachment assembly  18  compresses as the bolt  18   a  is pulled outward from the flange  14   a  of the main plow  14  (such as best shown in  FIG. 12 ). As shown in  FIG. 12 , the biasing element  20   c  of the lower attachment assembly  20  (which is rearward of the upper attachment element  18 ), may slightly compress as the bolt  20   a  is slightly pulled from the flange  14   a , depending on where the rearward most point of contact is between the plow wing and the main plow. In other words, if the lower attachment element  20  is generally at the rearward most point of contact, then the plow wing may pivot at that point and thus only slightly pull the bolt  20   a  outward and thus only slightly compress the biasing element  20   c , but if the plow wing contacts the main plow substantially rearward of the lower attachment assembly  20 , then both bolts  18   a ,  20   a  may be pulled outward and both biasing elements  18   c ,  20   c  may be compressed (with the forward biasing element being compressed more than the rearward biasing element). 
         [0032]    In the illustrated embodiment, the biasing elements  18   c ,  20   c  are selected and sized so that the amount of compression of the biasing element allows for the front end of the plow wing to pivot inward by up to about 10 inches (see  FIG. 9 ) or outward by up to about 10 inches (see  FIG. 12 ). The biasing elements  18   c ,  20   c  may comprise any suitable compressible, resilient biasing material, such as a compressible or deformable elastomeric material or rubber material or the like. Optionally, the biasing elements  18   c ,  20   c  may comprise coil springs or the like, while remaining within the spirit and scope of the present invention. 
         [0033]    By spacing the bracket  18   b ,  20   b  from the flange  14   a  of the center plow, the holes of the bracket and flange assist in maintaining the bolt or element  18   a ,  20   a  in its generally horizontal orientation. Optionally, however, the biasing element may be compressed between the flange at the end of the center plow and the washer at the end of the bolt (without the additional bracket at the rear of the plow). Optionally, the attachment assembly may include a bushing or spacer between the bracket  18   b ,  20   b  and the flange  14   a , whereby the bolt  18   a  passes through the bushing or spacer, with the spacer providing enhanced strength and rigidity to the assembly. Optionally, the inboard end of the biasing element (the end furthest from the respective plow wing) may be fixedly attached at a bracket of the plow (that is spaced from the end flange of the plow) and an outboard end of the biasing element may be attached at the elongated element or bolt, whereby the biasing element may stretch or extend (instead of compressing) when the plow wing is pivoted relative to the center plow, while remaining within the spirit and scope of the present invention. 
         [0034]    Therefore, the present invention provides a plow assembly having plow wings that are attached at the ends of the center plow and pivotable or movable responsive to impact with an object. The plow assembly and plow wings are configured to allow inward or outward pivotal movement of the plow wings, whereby the attachment elements bias the plow wings toward their initial or neutral or straight configuration so as to return the plow wing or wings to be generally normal to the main plow after the impact with the object. The attachment assemblies that allow for the limited pivotal movement of the plow wings are located entirely rearward of the main plow moldboard, and thus do not interfere with the curved plowing surface of the moldboard. By eliminating or avoiding use of struts or the like that extend forward of the center plow to support the forward end region of the plow wing and that thus are in the path of motion of the material being plowed and interfere with the movement of the material, the plow wings and attaching/biasing assemblies of the present invention significantly improves the rolling motion of snow upward along the center plow during plowing of snow (or other material). Thus, the plow wings and attachment assemblies of the present invention allow for controlled limited pivoting of the plow wings (such as when one of the plow wings impacts an object during plowing) while allowing the curved moldboard to plow the snow or other material in an efficient and effective manner (without struts or other elements disposed at the moldboard to retain the plow wings at the moldboard). 
         [0035]    Changes and modifications in the specifically described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law.

Summary:
A plow assembly includes a mounting structure configured to mount at a vehicle, a center plow attached at the mounting structure, and a plow wing mounted at an end of the center plow via a first attachment assembly and a second attachment assembly. Each of the first and second attachment assemblies includes an elongated attachment element and a biasing element. The elongated attachment element attaches a respective rear portion of the plow wing at the center plow and engages the biasing element at the rear of the center plow. The biasing element allows for movement of the attachment element at the rear of the center plow to allow for pivotal movement of the plow wing relative to the center plow. The biasing element limits pivotal movement of the plow wing and biases the plow wing towards a neutral state, where the plow wing is generally normal to the center plow.