Abstract:
A frame attachment and link between a materials moving implement, for example a dozer blade, and a vehicle for instance a conventional farm tractor which enables the operator to laterally adjust and raise and lower the dozer blade a substantial distance and yet is relatively easily connected and disconnected with the vehicle. The attachment described herein is a U-shaped frame having a front end including a central pivot attachment point at the base of the U, and several hydraulic attachment points which permit the lateral movement of the dozer blade relative to the vehicle. The U-shaped frame defines an opening which is large enough to accommodate the front frame and body of the of the tractor or vehicle so that the U-shaped frame when in a raised position, encompasses within the opening the front frame and body of the vehicle so that there is sufficient vertical articulation of the dozer blade without interference from the vehicle body.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a vehicle hitch attachment assembly utilized generally on tractors such as wheeled and tracked farming and agricultural tractors. In particular, the present invention relates to a highly articulated hitch attachment assembly for securing a dozer blade or similar materials moving implement to a tractor that surrounds and encompasses the front end of the tractor. 
       BACKGROUND OF THE INVENTION 
       [0002]    Various styles of hitches to support materials moving implements, e.g. buckets, blades, shovels, forks, etc., on vehicles are used across the agricultural and industrial equipment industry. Vehicles may be of the loader or tractor type and in particular work vehicles such as wheeled and tracked tractors for attachment of implements to the front and back of the work vehicle for moving desired materials, e.g. earth, snow, agricultural products and debris just to name a few. Very often on a farm tractor for instance, it is desired to mount a dozer blade for material handling and moving purposes. Usually, such implements need to be mounted to the front of the vehicle. While there are a number of standard hitches which allow relatively static attachment of such dozer blades to the front of a tractor, there are few if any which permit both substantial lateral and vertical, as well as tilting articulation of the blade relative to the tractor and the ground. In the known types of relatively static implement attachments, a vehicle operator must maneuver the vehicle in a manner which is awkward and less efficient than if the dozer blade is permitted to have independent vertical, tilting and lateral movement capabilities. 
         [0003]    There are for example known in the industry three point hitches which can be front or rear mounted to a three point hitch implement such as the dozer blade secured to the vehicle. One of the problems with standard three point hitches is that the hitch and link for the implement such as a dozer blade significantly spaces the implement from the front of the vehicle. Because the attachment point of the link extends forward of the front of the vehicle the upper pitch link substantially increases the distance separating the implement from the forward most point of the work vehicle. As a result, the mass balance of the vehicle and implement can be significantly changed and the operator is often separated by a great distance from the object they are trying to move, or from an intersection where visibility is critical. For these reasons, many regulations have set limits for the maximum distance that the operator can be spaced from the forward most point of the work vehicle. For example, some European regulations limit the distance separating the forward most point to the vehicle from the steering wheel to 3.5 m. 
         [0004]    Because in such three point hitches the implement is carried well forward of the work vehicle&#39;s center of mass, and forward of the front axle, the mass of the implement carried by a hitch can transfer larger undesirable loads to the work vehicle. The larger loads reduce vehicle stability and create greater loads on the drive trains of the vehicles during transport and field operations. Furthermore, in the known three point hitches the ability of the vehicles to raise and lower the dozer blade implement to a sufficient height relative to the ground in certain circumstances is either non-existent, or compromised by the mass and dimensions of the vehicle body which can interfere with any mechanism or attachment which might raise or lower the implement relative to the ground and the front of the vehicle. 
         [0005]    Thus, there is a continuing need for a front mounted hitch and attachment system to permit the desired articulation for an implement supported on a vehicle wherein the mass of the implement is carried as close to the vehicle as possible to reduce stresses and safety issues with respect to operation of work vehicle. The below described attachment system provides a pivot point as close to the front of the vehicle and front axle of the vehicle as possible, and also includes a frame which is able to accommodate the front of a work vehicle within it so as to provide a sufficient raise and lower height adjustment and articulation for the dozer blade as well as side-to-side adjustment, i.e. lateral movement of the dozer blade. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides for a frame attachment and link between a materials moving implement, for example a dozer blade, and a vehicle for instance a conventional farm tractor which enables the operator to laterally adjust and raise and lower the dozer blade a substantial distance and yet is relatively easily connected and disconnected from the vehicle. The attachment described herein is a U-shaped frame having a front end including a central pivot attachment point at the base of the U, and several hydraulic attachment points which permit the lateral movement of the dozer blade relative to the vehicle. The U-shaped frame is further provided with a rear pivot point extending between the free ends of the U, which is connected to a frame link and spaced from the front of the vehicle and as close to the front axle of the vehicle as possible. The U-shaped frame defines an opening which is large enough to accommodate the front frame and body of a tractor or vehicle so that the U-shaped frame when in a raised position, encompasses within the opening the front frame and body of the vehicle so that there is sufficient vertical articulation of the dozer blade without interference from the vehicle body. 
         [0007]    There are other critical factors to consider with such dozer blade implements as well, one of the most important being that the side support arms of the hitch for the dozer blade being in a lowermost operative position below the height of the front axle for the most effective pushing and cutting operations. Understanding that the lower cutting edge of a dozer blade absorbs and transmits the highest forces through the hitch to the vehicle, it is important to deliver those forces in the most linear manner as possible to the vehicle. In this operative position the side support arms must generally be aligned substantially parallel with the ground and at a lower height relative to the ground than the height of the front axle. This is important because it helps keep the center of gravity of the attachment and vehicle low to the ground and deliver the forces in the most linear manner, i.e. a very low angle, from the cutting edge of the dozer blade. 
         [0008]    For example opposite to most dozer blades, a front loader generally has side support arms that are well above the height of the front axle no matter what position the bucket is in and the forces are delivered at a very high angle to the vehicle. With the dozer blade having the side support arms positioned substantially entirely below the height of the front axle not only is the center of gravity of the hitch and blade maintained lower relative to the frame and center of gravity of the vehicle itself, but this arrangement also improves the steering of the vehicle. 
         [0009]    Also improving the steering and handling of the vehicle is the fact that the disclosed U-shaped frame member maintains the blade itself very close to the front of the vehicle while still being able to raise the U-shaped frame and the blade to encompass the body of the vehicle. Thus, even in a raised position the blade is very close to the front of the vehicle and good steering and handling of the vehicle can be maintained. 
         [0010]    The U-shaped frame member is attached to the body via a frame link which has a quick connect and disconnect frame attachment member for easily mounting and dismounting the U-shaped frame and frame link from the vehicle. The frame link also includes vertical hydraulic support attachment points which enables the vertical articulation of the U-shaped frame and blade implement. 
         [0011]    The present invention is directed to a materials moving implement attachment apparatus for a vehicle including a U-shaped frame having a first side member and a second side member connected at respective first ends by a base member extending therebetween, a blade support is provided on the base member for attachment of a materials moving blade, a rear pivot hinge connected between a respective second end of each of the first and second side member and the first and second side members define an opening therebetween having a larger dimension than a front body section of the vehicle permitting the U-shaped frame to be rotated about the rear pivot hinge and allowing at least a portion of the front body section of the vehicle to pass entirely through the space between the first and second side members. 
         [0012]    The present invention is also directed to a materials moving implement hitch for a vehicle including a U-shaped frame having a pair of generally parallel side members, each side member having a vertical actuator attachment and a horizontal actuator attachment, a base member connecting forward ends of the side members, a blade support affixed to the base member for attachment of a materials moving blade, a rear pivot brace affixed to the rearward end of each side member, a frame link for vertically, pivotally affixing the U-shaped frame to a vehicle, the frame link having a pair of oppositely disposed mounting plates, each mounting plate adapted to secure to a vehicle and rotatably engage with one of the pivot braces of the U-shaped frame, and wherein the pair of generally parallel side members are spaced apart a distance exceeding a width of a front body portion of the vehicle and the U-shaped frame is movable between a first position substantially parallel aligned with a ground surface below the front body portion of the vehicle and a second position wherein U-shaped frame rotates about the frame link to encompasses the front body portion of the vehicle between the generally parallel side members. 
         [0013]    The present invention is also directed a method for manufacturing a materials moving implement attachment apparatus for a vehicle including forming a U-shaped frame having a first side member and a second side member connected at respective first ends by a base member extending therebetween providing a blade support on the base member for attachment of a materials moving blade, connecting a rear pivot hinge between a respective second end of each of the first and second side members, and defining an opening between the first and second side members having a larger dimension than a front body section of the vehicle permitting the U-shaped frame to be rotated about the rear pivot hinge and allowing at least a portion of the front body section of the vehicle to pass entirely through the space between the first and second side members. 
         [0014]    These and other features, advantages and improvements according to this invention will be better understood by reference to the following detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0015]    Several embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings in which: 
           [0016]      FIG. 1  is a side elevation-view of the front hitch attachment mechanism in a raised position in accordance with the present invention; 
           [0017]      FIG. 2  is a side elevation-view of the front hitch attachment mechanism in a lowered position; 
           [0018]      FIG. 3  is a perspective view of a tractor front hitch attachment mechanism in a raised elevated position; 
           [0019]      FIG. 4  is a perspective view of the U-shaped frame member of the front hitch attachment mechanism; 
           [0020]      FIG. 5  is a top plan view of the U-shaped frame member; 
           [0021]      FIG. 6  is a perspective right-side view of the U-shaped frame member and frame link of the attachment mechanism; 
           [0022]      FIG. 7  is a side elevation view of the hitch attachment, hydraulics and blade implement; 
           [0023]      FIG. 8  is a perspective view of the hitch attachment, hydraulics and blade implement; 
           [0024]      FIG. 9  is a top plan view of the hitch attachment, hydraulics and blade implement; 
           [0025]      FIG. 10  is a top plane view of the U-shaped frame member and frame link supported on a vehicle and the vehicle frame and body within the open area defined by the U-shaped frame; 
           [0026]      FIG. 11  is a side elevation and cutaway-view of the front hitch attachment mechanism in a raised position with the quick-release assembly of the hitch and vehicle frame shown with a materials moving blade attached in accordance with the present invention; 
           [0027]      FIG. 12  is a cross-section view of the quick-release assembly in a hitch unsecured arrangement; 
           [0028]      FIG. 13  is a perspective view of the quick-release assembly in the unsecured arrangement; 
           [0029]      FIG. 14  is a cross-section view of the quick-release assembly in a hitch secured arrangement; 
           [0030]      FIG. 15  is a perspective view of the quick-release assembly in the hitch secured arrangement; 
           [0031]      FIG. 16  is a perspective view of another embodiment of a quick-release assembly; 
           [0032]      FIG. 17  is a side elevation view of this further embodiment of a quick-release assembly in an unsecured position; and 
           [0033]      FIG. 18  is a side elevation view of this further embodiment of a quick-release assembly in a secured position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0034]      FIGS. 1 and 2  are side elevation views of a body of a vehicle  5  and a hitch attachment  1  showing a U-shaped frame  3  in a raised and lowered position, respectively. The U-shaped frame  3  is shown here without any of the requisite hydraulics which motivate the U-shaped frame up and down. Nor is a blade or materials moving implement shown supported on the frame member here for purposes of clarity of the following initial description. It is to be appreciated that in the lowered position as shown in  FIG. 2  a blade implement would normally be resting on the ground so that materials can be efficiently moved. There is an angle P defined between the U-shaped frame  3  and a frame link bracket  42  such that the U-shaped frame  3  can raise and lower the blade implement substantially vertically relative to the ground around the front of the vehicle between the raised and lowered positions of the attachment. The angle P is generally established between 0-90 degrees or alternatively between about 0-60 degrees and with a preferred angle P being between about 0-45 degrees. It is to be appreciated as shown in  FIG. 2  that the angle P includes at least a portion of the tractor body  5  and/or frame F so that the body  5  and frame are encompassed within the U-shaped frame in its uppermost, raised positions. Such raising and lowering of the U-shaped frame  3  is caused by the extension of a hydraulic piston extending between an upper rear hydraulic attachment point  51  on the frame link bracket  42  and a lower hydraulic attachment point  33  on the U-shaped frame  3 . 
         [0035]      FIG. 3  is a perspective view of the hitch attachment assembly  1  including the U-shaped frame  3  in the raised position in conjunction with the front body portion  5  of an agricultural tractor. From a structural standpoint, the U-shaped frame  3  is generally defined by a left side member  9  and a right side member  11  connected by a base member  13  supporting a central pivot  15  at the front of the U-shaped frame  3 . It is to be appreciated that the central pivot  15  on the front of the U-shaped frame  3  is the main direct connection and support of the blade or materials moving implement by the U-shaped frame  3 . The central pivot  15  is defined about a main axis A through which a connecting portion of the blade implement is enabled to rotate so as to provide lateral movement of the implement about the main axis A relative to the U-shaped frame  3  and the vehicle  5 . The lateral movement is caused by the extension of a hydraulic piston extending to the blade implement from a rear lateral hydraulic attachment point  21  as will be further described below. 
         [0036]    Turning to  FIG. 4 , the U-shaped frame  3  is comprised of the left side member  9  and the right side member  11  joined by a base member  13  extending between the respective ends of the left and right side members  9 ,  11  to form the bottom portion of the U-shape. The base member  13  is shown having an apex defining the central pivot  15  which rotatably supports a matching engagement part of a blade implement. The central pivot  15  and the apex of the base member  13  are reinforced on a front side with a central pivot gusset  27  supporting and securing the central pivot  15  to the base member  13  on either or both sides of the apex. Additionally, a reinforcement support member  29  is provided on the back side of the base member  13  which extends as a linear chord between the side members so that a strengthening triangle is formed with the base member  13  of the U-shaped frame  3  to directly support the connection of the central pivot  15  with the materials moving implement. A further direct support bar  30  may also be placed between a central portion of the reinforcement support member  29  and the apex of the base member  13  to further support the central pivot  15 . It is also to be appreciated that the base member  13  does not need to form a perfect triangle, but may also be formed as a portion of a curve rather than two straight sections as seen in  FIG. 4  extending to form the apex, and could potentially be contiguously and integrally formed with the side members as well. 
         [0037]    It is important that the left side member  9 , right side member  11 , base member  13  as well as at least the support member  29  are fabricated from hollow stock material, for example hollow steel stock, so that essentially off-the-shelf, inexpensive materials can be used to fabricate the main portions of the U-shaped frame  3 . In this way only the end plates of the frame which form for example corner gussets  28  and rear pivot braces  37  discussed in further detail below, need to be cut, welded and formed by additional labor. This is a tremendous cost savings whenever inexpensive hollow bar stock can be used in fabrication. Many of the known dozer blade support arms are almost entirely formed from custom cut plate so that the entire hitch and blade support is expensive and time consuming to manufacture. 
         [0038]    In the embodiment shown in  FIG. 4 , a corner gusset  28 , or gussets are also provided at the intersection of the base member  13 , the respective left and right side member  9 ,  11  and the reinforcement support member  29  to further strengthen this part of the U-shaped frame  3 . The front vertical hydraulic attachment point  33  is provided in conjunction with the corner gusset(s)  28  to facilitate raising and lowering of the U-shaped frame  3 . The U-shaped frame  3  also includes a rear pivot hinge  35  about which the entire U-shaped frame  3  rotates to provide upward and downward adjustment of the U-shaped frame  3  and blade, i.e. vertical movement of the blade implement. Each of the rear pivot hinges  35  are supported by a rear pivot brace  37 . The rear pivot brace  37  has an angled first end  38  supporting one end of the rear pivot hinge  35 , a central support portion  39  and a lateral second end  40  that receives a rear end of the side members  9 ,  11  of the U-shaped frame  3 . A rear pivot hinge support  36  is connected between each of the rear pivot hinges  35 .  FIG. 5  is a top view of the U-shaped frame  3  showing the central pivot gusset  27 , the side gusset(s)  28  and rear pivot brace(s)  37  enclosing the base member  13  and side members  9 ,  11  to strengthen and support the structure of the U-shaped frame  3 . 
         [0039]    As better seen in  FIG. 2 , the angled end  38  of each rear pivot support  37  is angled upwards from a first plane defined by the side and base members of the U-shaped frame  3  so that a portion of the rear pivot brace  37  is itself aligned along a second plane, or an axis spaced from that defined by the side members  9 ,  11  and base member  13  of the U-shaped frame  3 . This relative spacing caused by the angled end portion  38  of each rear pivot brace  37  defines the difference in the planar separation between the rear pivot hinge  35  and the left and right side members  9 ,  11  and base member  13  and substantially facilitates the articulation and height adjustment of the U-shaped frame  3  and blade implement relative to the body  5  of the vehicle. 
         [0040]    As shown in  FIG. 6  the other part of the attachment assembly  1 , a frame link  41 , directly supports the U-shaped frame  3  to the body  5  of the vehicle. As will be discussed in further detail below, this frame link  41  not only rotatably supports the U-shaped frame  3  and secures it directly to the vehicle body  5 , but also includes hydraulic attachment points  51  and an angular or sloped edge  59  forming a stop surface for limiting the vertical articulation of the U-shaped frame  3  about the front of the vehicle  5  or tractor. The terms vehicle  5  and tractor are used interchangeably to describe the general type of vehicle which maneuvers and carries the hitch attachment  1  and blade implement, many types of agricultural and industrial vehicles may certainly be contemplated by the present invention. 
         [0041]    The U-shaped frame member  3 , in particular the rear pivot hinge  35  is directly supported by the frame link  41  shown in  FIG. 3  which is directly and immovably fixed to the frame or body  5  of the vehicle. For purposes of discussion we refer to the frame and body of the carrying vehicle, as the vehicle “body” to differentiate it from the other uses of the term “frame” herein. The frame link  41 , not shown attached to the vehicle body  5  in  FIG. 6  for purposes of description, performs two important functions, first and foremost it rotatably supports the U-shaped frame  3  at the rear pivot hinge  35  and allows it to rotate about the rear pivot hinge  35  and raise and lower the blade implement. Secondly, the frame link  41  can be quickly and easily attached and detached to the vehicle body  5  via a hanger arrangement. The frame link  41  includes a pair of mounting plates  48  mated with the rear pivot hinge  35  and inserted in the angled end  38  of the rear pivot brace  37 . The bracket  42  and a link support  52  extend between and connect the mounting plates  48 . A hanger  43  is formed at one end of each mounting plate  48  and a securing hole  49  is formed at the other end of each mounting plate  48 . A pair of laterally extending studs  44  (not shown) are welded, or otherwise attached to the vehicle body  5  and have a dimension intended to fit snugly and be received within a channel  45  defined in the hanger portion  43  of the mounting plate  48  of the frame link  41 . 
         [0042]    As shown in  FIGS. 7 and 8 , where the blade implement and hitch attachment are set on the ground and not engaged with a vehicle, the hanger  43  is maintained at a height which matches the height of the extending studs on the vehicle body. In order to initially secure the hitch attachment  1  and/or the blade to a vehicle  5 , the operator of the vehicle  5  merely needs to center the vehicle over the attachment  1  and drive forward bringing the studs  44  which are affixed to vehicle body  5  into contact and engage them within the U-shaped hangers  43  on the frame link  41 . Then, the operator need only set a securing bolt  47 , or a quick release mechanism discussed in detail below, through the respective securing holes  49  to engage the U-shaped frame  3  with a portion of the vehicle frame, or a specific mount provided on the vehicle frame, in order to provide full and complete support for the attachment  1  and implement. It is to be appreciated that the studs  44  may be permanently fixed, welded or otherwise affixed to the body of the vehicle and are small enough so that they do not interfere with any other implements or use of the vehicle except to easily connect and disconnect the frame link  41  and hitch attachment  1  as described above. 
         [0043]    As can be seen in  FIG. 6 , the frame link  41  also includes a vertical hydraulic support attachment point  51  on the frame link bracket  42 . This hydraulic support attachment point is for the rear end of the vertical hydraulic pistons which, at the front end of the piston, are attached to the front vertical hydraulic attachment points  33  on the U-shaped frame  3  to motivate the U-shaped frame member up and down about the rear pivot hinge  35 . In  FIG. 7  the vertical hydraulic piston  61  can easily be observed as it extends between the relative attachment points on the frame link bracket  42  and the U-shaped frame  33 . Also here can be seen arranged substantially parallel with the U-shaped frame is the lateral hydraulic piston  63  for controlling the lateral movement of the blade implement  60  about the central pivot  15 . The lateral hydraulics would generally connect from the lateral hydraulic attachment point  21  on the rear pivot brace  37  directly to the backside of the blade implement  60  for controlling a lateral rotation of the blade implement about the central pivot point  15 . A further description of the associated hydraulics is provided below with respect to  FIGS. 8 ,  9  and  10 . 
         [0044]    Turning to  FIGS. 8 and 9 , a perspective and top plane view of the vertical and lateral hydraulic pistons discussed above is shown. Also seen here is the left and right tilt hydraulics  65  which enables the blade implement  60  to rotate about a central longitudinal axis X perpendicularly intersecting the central pivot axis A. In this way the operator may not only raise and lower the blade implement  60 , and rotate the blade laterally about the substantially vertical pivot axis, but it may also be tilted to the left and right about the central longitudinal axis X to change the relative heights of the left and right side of the blade implement relative to the ground surface, for instance to dig a ditch along the side of a road. For further frame of reference, the central longitudinal axis X is generally drawn along i.e. parallel with, the direction of travel of the vehicle  5  and blade implement  60 . In this way the blade implement  60  is connected to the U-shaped frame  3  along two axes of rotation, the central pivot A and a central longitudinal pivot X and where the rotation of the U-shaped frame  3  about the rear pivot hinge  35  provides a relative height adjustment of the entire blade  60  relative to the vehicle  5  and the ground. 
         [0045]      FIG. 9  shows the width W of the opening O defined by the U-shaped frame  3 . The width W is wider than the front of the tractor as clearly seen in  FIG. 10  so that the U-shaped frame is free to be raised to any level and encompass the tractor body between the left and right side members  9 ,  11  without interference. Generally it is the vertical hydraulic piston  61  which will define the height to which the U-shaped frame can be raised around the front body portion of the tractor or vehicle and which ensures that the frame is not raised so high as to have the base member  13  or reinforcement member  29  contact the front of the tractor body. The hydraulic pistons  61  are also outside the width of the tractor as shown in  FIG. 9  to ensure that the pistons  61  are not inhibited by the tractor body as well. 
         [0046]    In this way, the frame  3  can be permitted to be raised and lowered through the angle P as best seen in  FIG. 2  where the vertical rise of the hitch is met by a sloped edge  59  of the frame link  41  which limits the raising height of the U-shaped frame  3  before the base of the U-shaped frame can abut the front of the vehicle. 
         [0047]    The U-shaped frame  3  and frame link  41  as seen best in  FIG. 6  may be best attached to the vehicle by a quick release mechanism which includes a frame mount  70  shown in  FIGS. 11-15 . The frame mount  70  is directly attached to the frame F of the vehicle by outer support bar plates  71  and an axle bracket  73  including a support bar  75  extending between the outer support bar plates  71  best seen in  FIG. 12 . A pair of linearly and opposingly arranged hydraulic pin actuators  77  are supported by a carrier bracket  79  on the support bar  75  and extend parallel with the support bar  75 . The piston  81  of each of the hydraulic pin actuators  77  has at each end a pin  82  for securely engaging and attaching the U-shaped frame  3  and frame link  41  to the frame mount  70  and hence the vehicle. 
         [0048]    In the embodiment shown in  FIGS. 12 and 13 , which is the unsecured and retracted position of the frame and mount, each pin  82  is supported at one end by the attachment to the piston  81  and at a second end by a passage through an inner support bar plate  83 . An intermediate support bar plate  85  having a pin receiving passage  87  is axially spaced from the inner support bar plate  83  to define a receiving space  89  into which an end portion  41 ′ of the frame link  41  having the securing holes  49  is received. What is shown here for purposes of clarity is merely the end portion  41 ′ of the frame link  41  and part of the securing hole  49 . It is to be appreciated that it is the frame link  41  of course which directly supports the U-shaped frame  3  is now shown in this figure. 
         [0049]    As can be appreciated from the above disclosure and described structure along with  FIG. 13 , a tractor or vehicle  5  with the frame mount  70  attached underneath can be driven by the operator H, essentially over frame link  41  and into the U-shaped frame  3 , to engage the hanger  43  and permitting the end of the frame link  41  to enter the receiving space  89 . As will be explained in detail below, once this is accomplished the operator H need simply actuate the hydraulic pin actuators  77  from the cab of the tractor via the connected hydraulic system and hoses  84  and the pistons  81  and pins  82  extend through the securing holes  49  to secure the U-shaped frame  3  to the frame mount  70  and hence the tractor or vehicle  5 . 
         [0050]    The hydraulic pin actuators  77  along with the pin receiving passage  87  define a quick release axis Q. It is important to recognize that the quick release axis Q is parallel to but arranged lower relative to the ground than the front wheel axle as best seen in  FIG. 11 . This arrangement facilitates maintaining the forces which are applied through the hitch from the blade directly to the frame F at a plane which is lower than the vehicle axle. Where the forces from the blade are applied along a relatively straight angle of attack from the blade through the U-shaped frame  3  to the vehicle, and impacting the vehicle frame at a point below or even planarly aligned with the front axle of the tractor, this arrangement facilitates the stability and handling of the tractor. Any vehicle has generally better stability and handling when the center of gravity including any forces applied to the vehicle which can effect the center of gravity are maintained lower to the ground. This is particularly more difficult to achieve with tractors and other wheeled vehicles where the main road wheel axles may be located quite high for ground clearance purposes. This quick release hitch attachment facilitates maintaining these forces and centers of gravity of the vehicle as low to the ground as possible. 
         [0051]    The embodiment shown in  FIGS. 14 and 15  is the secured and extended position of the frame and mount, each pin  82  has now been extended by the respective hydraulic cylinders  77  and piston  81  through the inner support bar plate  83 , across the receiving space  89 , and into the pin receiving passage  87  of the intermediate support bar plate  85 . As the pin  82  crosses the receiving space  89  it passes through the securing holes  49  in the link end portion  41 ′ to connect the U-shaped frame  3  securely to the tractor or vehicle  5 .  FIG. 15  shows the extension in complete detail with pistons  81  extended securing the U-shaped frame  3  to the tractor  5 . 
         [0052]    In another embodiment of the quick release mechanism shown in  FIGS. 16-18 , a frame link  91  is provided with a spring loaded wedge bar  93  which extends and retracts to secure the frame and blade to the tractor. The frame link  91  includes a receiver  95  for engaging a transverse bar or pin  96  mounted underneath the vehicle or tractor on a frame mount  97  for example. As will be explained in further detail below, when the receiver  95  is engaged with the bar or pin  96  an operator actuates the spring loaded wedge bar  93  to secure the bar or pin  96  in the receiver  95  so that there is as little play, i.e. space, gap and movement, as possible between the receiver  95  and the bar or stud  96 . Experience has shown that any play between the mounting hardware and pin leads to faster product and mounting hardware deterioration. The spring loaded wedge bar  93  ensures constant contact and continuous pressure between the receiver  95  and bar or pin  96  so that such play is eliminated even with wear of the mounting hardware over time. 
         [0053]    As seen in  FIG. 17 , the wedge bar is connected via a link  101  to an actuator  103 . The actuator  103  rotates about an actuator axis X when manually or mechanically motivated. An operator may manually rotate the actuator  103  by inserting a handle or pipe (not shown) into either of the available sockets  105  integral with the actuator  103  to gain leverage. As can be appreciated by observing the difference between  FIGS. 17 and 18 , when an operator rotates the actuator  103  via the handle in the direction P, the actuator  103  motivates the link  101  to push the wedge bar  93  across the opening of the receiver and into engagement with the pin  96 . 
         [0054]    In the retracted position as seen in  FIG. 17 , the wedge bar  93  allows entry of the bar or pin  96  into the receiver  95 . The wedge bar  93  has a butt portion  107  and a tip portion  109  connected by a spring  111  which permits the tip portion a certain amount of bias and axial travel, i.e. compression, relative to the butt portion  107  The tip portion  109  includes a ramp  113  which is intended to contact in a tangential manner the bar or pin  96  as the wedge bar  93  is pushed across the opening into the receiver  95 . It is to be appreciated that as the ramp  113  contacts the pin  96  an axial force pushes the tip portion  109  against the bias of the spring  111  so that firm spring biased contact is ensured between the wedge bar  93  and the pin  96 . Because of the sloped nature of the ramp  113  the tip portion  109  is able to directly contact pins  96  of different diameters which may for example occur due to wear over time. 
         [0055]    As seen in  FIG. 18  because the axis of rotation of the actuator is axially aligned along the main axis W of the wedge bar  93 , with the mechanism now rotated into the engaged and extended position, the arrangement of the link  101  essentially locks the wedge bar  93  into an extended position and axial force along the axis W further locks the mechanism and wedge bar  93  against the pin  96  and at least partially across the opening of the receiver ensuring a firm, stable contact between the mounting hardware so that the hitch and blade is securely carried by the tractor. 
         [0056]    The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.