Abstract:
The entire right, title and interest in and to this application and all subject matter disclosed and/or claimed therein, including any and all divisions, continuations, reissues, etc., thereof are, effective as of the date of execution of this application, assigned, transferred, sold and set over by the applicant(s) named herein to Deere &amp; Company, a Delaware corporation having offices at Moline, Ill. 61265, U.S.A., together with all rights to file, and to claim priorities in connection with, corresponding patent applications in any and all foreign countries in the name of Deere &amp; Company or otherwise.

Description:
[0001]     FIELD OF THE INVENTION  
         [0002]     The present invention relates to grass mowing equipment with multiple rotary cutting decks, and specifically to mounting rotary cutting decks to the ends of lift arms extending laterally from a traction vehicle.  
       BACKGROUND OF THE INVENTION  
       [0003]     Grass mowing equipment for large areas may include multiple rotary cutting decks, each rotary cutting deck mounted to the end of an independent lift arm extending from a traction vehicle. For example, each rotary cutting deck may be mounted to the forward end of a lift arm using a mounting device that includes a yoke with a crossbar that extends laterally over and spans the cutting deck. The yoke or crossbar may be attached at pivoting joints in side plates at the left and right edges of the deck. When the rotary cutting deck is on the ground, the mounting device should allow for pitch (front to back pivoting) and yaw (side-to-side pivoting).  
         [0004]     A mounting device for a rotary cutting deck should satisfy several requirements. For example, the mounting device needs to absorb shocks from impacts while maintaining its integrity. The mounting device should limit the maximum tilt and yaw angles so they do not exceed ANSI limits. When the rotary cutting deck is raised for transport, the mounting device should provide sufficient stability to prevent the deck from swinging wildly during vehicle turns, or during sudden starts or stops. The mounting device should allow the rotary cutting deck to pitch as required to drive the vehicle up standard trailer ramps without bottoming out.  
         [0005]     Some existing mounting devices for rotary cutting decks satisfy at least some of these requirements, but the mounting devices tend to be heavy, bulky and expensive to manufacture. A relatively simple, inexpensive mounting device for a rotary cutting deck is needed that can absorb shocks from impacts, limit maximum tilt and yaw angles, provide sufficient stability to prevent the deck from swinging excessively when raised for transport, and allow the deck to pitch as required to drive up trailer ramps.  
       SUMMARY OF THE INVENTION  
       [0006]     A mounting apparatus for a rotary cutting deck includes a T-shaped pivot pin with a post inserted into a socket in the forward end of a lift arm. A channel shaped bracket between the T-shaped pivot pin and the rotary cutting deck provides a pair of pivoting connections for the deck to pitch. A first pivoting connection allows the bracket to pivot with respect to the T-shaped pivot pin on a first pivot axis, and a second pivoting connection allowing the bracket to pivot with respect to the rotary cutting deck on a second pivot axis parallel to the first pivot axis. The T-shaped pivot pin also provides a third pivot axis for the rotary cutting deck to yaw. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a partially exploded perspective view of a rotary cutting deck mounted to a lift arm according to a first embodiment of the invention.  
         [0008]      FIG. 2  is a perspective view of a rotary cutting deck mounted to a lift arm according to a first embodiment of the invention.  
         [0009]      FIG. 3  is a perspective view of a traction vehicle carrying rotary cutting decks mounted to lift arms according to a first embodiment of the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0010]     As shown in  FIGS. 1 and 2 , in a first embodiment, rotary cutting deck  10  may carry a motor such as hydrostatic motor  11  to turn a cutting blade attached to a generally vertically aligned spindle under the deck. Optionally, the rotary cutting deck may be supported over the ground surface by anti-scalp wheels or rollers that may be adjusted to raise or lower the deck to a desired cutting height.  
         [0011]     In  FIGS. 1 and 2 , only one rotary cutting deck is shown.  FIG. 3  shows traction vehicle  30  that may carry multiple rotary cutting decks, each rotary cutting deck supported by a lift arm  16  extending from the vehicle. Each cutting deck may be raised and lowered by use of hydaulic controls that may be operated from the vehicle.  
         [0012]     In one embodiment, a first or back end of each lift arm  16  may be pivotably connected to a frame member at the side or front of the traction vehicle. The second or forward end of the lift arm may be attached to the rotary cutting deck so that the deck may yaw (pivot side-to-side) and pitch (pivot front-to-back).  
         [0013]     In one embodiment, channel shaped bracket  13  may be pivotably attached to rotary cutting deck  10  by inserting a first pair of pivot bushings  29  through holes in the channel shaped bracket at axis C. Axis C may be generally horizontal and perpendicular to the direction of travel. When the first pair of pivot bushings are inserted through the holes at axis C to align with pivot axis A, the channel shaped bracket may pivot front-to-back with respect to rotary cutting deck  10 .  
         [0014]     In one embodiment, the first pair of pivot bushings  29  may be fastened to each of the right and left arms  14 ,  15  that extend from the rear of the rotary cutting deck forwardly adjacent the right and left sides of the deck. The first pair of pivot bushings may be fastened to the right and left arms on axis A which is horizontal and parallel to the ground, perpendicular to the direction of travel, and substantially toward the rear end of the rotary cutting deck.  
         [0015]     In one embodiment, channel shaped bracket  13  may be pivotably attached to lift arm  16  by inserting a second pair of pivot bushings  21  through the holes in channel shaped bracket at axis D. Axis D also may be horizontal and perpendiuclar to the direction of travel. When the second pair of pivot bushings are inserted through the holes at axis D to align with pivot axis B, the channel shaped bracket may pivot front-to-back with respect to lift arm  16 . Axis B is parallel to axis A.  
         [0016]     In one embodiment, the second pair of pivot bushings  21  may be fastened to each end of crossbar  20  of T-shaped pivot pin  18  along axis B. Post  19  of the T-shaped pivot pin may be inserted into socket  17  in the second end of lift arm  16 , and retained with a cross pin. The slot in post  19  may allow the T-shaped pivot pin to turn within the socket, which provides for a side-to-side, or yaw, pivot. This pivoting is on a third generally horizontal axis that is parallel to the direction of travel.  
         [0017]     In one embodiment, the mounting device provides two parallel pivot axes for additional pitch freedom for a rotary cutting deck. This is accomplished by providing channel shaped bracket  13  with two axes allowing front-to-back pivoting.  
         [0018]     In one embodiment, when the rotary cutting deck is on the ground surface, channel shaped bracket  13  may be tilted upward facing toward the front of the rotary cutting deck. The base of channel shaped bracket  13  may include slot or opening  22  through which the second end of lift arm  16  and/or post  19  may be inserted. By this arrangement, the dimensions of slot or opening  22  may provide limits for front-to-back pivoting of the rotary cutting deck, as will be explained below.  
         [0019]     In one embodiment, the rear end  23  of slot or opening  22  may be positioned to contact the bottom of lift arm  16  to limit how low the lift arm can move down relative to the rotary cutting deck. The front end  24  of slot or opening  22  may be positioned to limit how far channel shaped bracket  13  can pivot down relative to the lift arm.  
         [0020]     In one embodiment, the rear end of channel shaped bracket  13  may include notch  25  that may contact a structural member on or adjacent the rear of the rotary cutting deck to limit the maximum angle of rotation of the channel shaped bracket relative to the deck.  
         [0021]     In one embodiment, when the rotary cutting deck is on the ground surface, lift arm  16  may be loaded in the downward direction by a hydraulic cylinder or other means such as springs. In the downward loaded position, rear end  23  of slot or opening  22  is forced against the bottom of lift arm  16 . This force urges the rotary cutting deck in the downward direction.  
         [0022]     In one embodiment, if lift arm  16  is then raised, channel shaped bracket  13  rotates relative to the lift arm until notch  25  at the rear of the channel shaped bracket contacts a structural member at the rear of the rotary cutting deck. When notch  25  contacts the structural member on the deck, the rear of the deck starts to be lifted. As the rear of the rotary cutting deck rises, the center of gravity of the deck aligns with the D and B pivot axes and the deck hangs in a substantially horizontal position, which may be parallel with the ground.  
         [0023]     In one embodiment, the forward end of lift arm  16  may include a U-shaped pin  26  welded to the outside of the lift arm. The two ends of pin  26  may be parallel, and the pin may be located so that one of its parallel legs may be located vertically on top of the lift arm when the lift arm is in its fully raised position. The outboard leg of pin  26  may be tangent to the lift arm. Channel shaped bracket  13  may have a notch  27  at the forward end  24  of slot or opening  22 . As lift arm  16  is raised and channel shaped bracket  13  pivots downward, notch  27  engages the leg of U-shaped pin  26  and locks up the yaw pivot, thus stabilizing the rotary cutting deck in its raised position.  
         [0024]     In one embodiment, as lift arm  16  is lowered, notch  27  disengages from U-shaped pin  26 , so that the rotary cutting deck can pivot side-to-side as it reaches the ground contour. U-shaped pin  26  also may provide an additional function. T-shaped pivot pin  18  may have a web  28  on both sides between post  19  and crossbar  20 . When lift arm  16  is down, either side of pivot pin web  28  may contact a leg of the U-shaped pin  26  which provides an abutment that blocks excessive side-to-side pivoting, or yaw, of the cutting deck beyond a specified ANSI limit.  
         [0025]     The invention provides a relatively simple and inexpensive apparatus for a rotary cutting deck to be mounted to a lift arm and provide for full float of the deck for following ground contours. Additionally, the mounting device allows sufficient forward pivot angle so that trailer ramps may be climbed without bottoming out. Further, the mounting device provides for stabilization of cutting units in the raised, or transport, position.  
         [0026]     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.