Abstract:
A mower suitable for attachment to a utility vehicle and adapted to follow terrain and retract in response to an immovable obstacle, the mower generally including an attachment frame configured to be pivotally attached to the utility vehicle, a secondary frame pivotally connected to the attachment frame, and a housing positioned adjacent to the secondary frame and being laterally movable with respect to the secondary frame, wherein the housing retracts in a direction toward the secondary frame when contact occurs between the housing and the immovable obstacle and automatically returns to an approximate pre-contact position when contact between the housing and the immovable obstacle is eliminated.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to mowers and, more particularly, to a mower having a cutting blade which retracts in response to an obstruction. 
     2. Brief Description of the Prior Art 
     U.S. Pat. No. 3,045,413 to Sheffer generally discloses a cutting blade and guard attached to a springed, laterally extending post. The cutting blade, guard, and post are supported by a hydraulic lever arrangement. The cutting blade is rotated by a motor, belt, and pulley. 
     U.S. Pat. No. 4,901,508 to Whatley generally discloses a fence row mower with a plurality of rotary blade units driven by a series of pulleys. Pressure cylinders are used to maneuver the plurality of rotary blade units. 
     In general, the known prior art must be supported or maneuvered by complex means, such as by pressurized fluid systems. This is expensive and adds to overall maintenance costs. Moreover, the prior art teaches using complicated blade drive units to rotate a cutting blade. Therefore, a need exists for a mower with a simplified cutting blade driver and a cutting blade that extends and retracts quickly from a utility vehicle without the need for complex fluid pressure systems. 
     SUMMARY OF THE INVENTION 
     In order to help satisfy the needs not currently met by the prior art, one embodiment of the present invention generally includes a mower adapted to follow terrain and retract in response to an immovable obstacle. The mower generally includes a utility vehicle, an attachment frame configured to be pivotally attached to one side of the utility vehicle, a secondary frame pivotally connected to the attachment frame, and a housing positioned adjacent to the secondary frame. The housing is preferably laterally movable with respect to the secondary frame via biasing means. In one method of operation, the housing retracts in a direction toward the secondary frame when contact occurs between the housing and the immovable obstacle and automatically returns to a pre-contact position when contact between the housing and the immovable obstacle is eliminated. 
     In sum, the present invention seeks to improve the mower art by providing a mower with an automatically biased cutting blade assembly. No hydraulic lifts or actuators are required to move the cutting blade assembly or to pivot the cutting blade assembly in response to uneven terrain. The cutting blade is directly attached to a vertical shaft, which in turn, is directly connected to a motor. When an immovable object, such as a fence post, is encountered, the automatic biasing action of the cutting blade housing helps to quickly and automatically return the cutting blade to a pre-contact position and significantly eliminates spots of uncut vegetation growing between adjacent fence posts. 
     These and other advantages of the present invention will be clarified in the description of the preferred embodiment taken together with the attached drawings in which like reference numerals represent like elements throughout. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top perspective view of a mower according to the present invention; 
     FIG. 2 is a top exploded perspective view of the mower shown in FIG. 1; and 
     FIG. 3 is a top plan view of the mower shown in FIGS.  1  and  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A mower  10  according to one embodiment of the present invention is generally shown in FIG.  1 . The mower  10  includes an attachment frame  12  configured to be pivotally attached to a utility vehicle  8 , a secondary frame  14  pivotally connected to the attachment frame  12 , and a cutting blade assembly  16  laterally movable relative to the cutting direction in the A 1  and A 2  directions with respect to the secondary frame  14 . The attachment frame  12 , secondary frame  14 , and cutting blade assembly  16  are preferably made from metal, such as steel or other suitable material, unless otherwise specified. 
     As shown in greater detail in FIG. 2, the attachment frame  12  is configured to be pivotally connected to a hitch  18 , which in turn, is rigidly connected to the utility vehicle  8 . In the preferred embodiment, the pivotal connection is acquired by aligning orifices O 1  defined by spaced apart pin receiving cylinders  20  positioned adjacent to a first frame member  24  of the attachment frame  12 , with corresponding orifices O 2  defined by second pin receiving cylinders  20 A attached to the hitch  18  and inserting pins  22  through the aligned orifices O 1 , O 2 . The combination of the spaced apart pin receiving cylinders  20  and the second pin receiving cylinders  20 A defines a first articulated joint. 
     In addition to the first frame member  24 , the attachment frame  12  further includes two, spaced apart second frame members  26 . Each of the two, spaced apart second frame members  26  have a first frame end  28 , with each first frame end  28  connected to the first frame member  24 . Each of the two, spaced apart second frame members  26  are preferably oriented perpendicular to the first frame member  24 . 
     A first wheel support  30  is generally positioned perpendicular to the two, spaced apart second frame members  26  and is preferably spaced away from and substantially parallel to the first frame member  24 . The first wheel support  30  can be a single bar or the spaced apart dual bar shown in FIG. 2. A first wheel  32  is positioned adjacent to a first support end  34  of the first wheel support  30 , and a second wheel  36  positioned adjacent to a second support end  38  of the first wheel support  30 . The first and second wheels  32 ,  36  may be made from rubber or plastic and are preferably configured to roll in a direction coincident with an imaginary longitudinal axis L extending through the first wheel support  30 . 
     The secondary frame  14  is pivotally connected to the attachment frame  12  via second joint brackets  40  positioned adjacent to second frame ends  42  of the two, spaced apart second frame members  26 , pin holes  50  (discussed below), and pins  22 . This combination is herein defined as a second articulated joint. The secondary frame  14  generally includes two, spaced apart, C-shaped channel members  44 , each connected to a corresponding channel bar  46 . The two, spaced apart channel members  44  and corresponding channel bars  46  are connected to one another by a generally C-shaped retention bar  48 . 
     Each channel bar  46  defines the pin holes  50  discussed above and movement restraint pins  52  at a third end  54  and retention member posts  56  at a fourth end  58 . A third wheel  60  is positioned adjacent to the fourth end  58  of one of the two, spaced apart channel members  44 , and a fourth wheel  62  is positioned adjacent to the fourth end  58  of the other one of the two, spaced apart channel members  44 . The third wheel  60  and the fourth wheel  62 , which may be made from rubber, plastic, or other suitable material, are also aligned to travel in the same direction as the first wheel  32  and the second wheel  36 . 
     The cutting blade assembly  16  is laterally movable in the A 1  and A 2  directions with respect to the secondary frame  14 . The cutting blade assembly  16  generally includes a housing  64 , with the housing  64  preferably defining a circularly-shaped outer perimeter. A motor mount  66  is attached to a first top surface  68  of the housing  64 . Both the motor mount  66  and the housing  64  define a coincident motor shaft orifice  70 . 
     One or more rollers  72  are positioned along first and second opposing sides  74 ,  76  of the motor mount  66 . The rollers  72  are each oriented to be received by a corresponding one of the two, spaced apart channel members  44  of the secondary frame  14 . 
     Second retention member posts  78  and movement restriction brackets  80  extend from a second top surface  82  of the motor mount  66 . A motor  84  is mounted to the second top surface  82  of the motor mount  66 , so that a vertical motor shaft  86  extending from the motor  84  extends through the motor shaft orifice  70 . A rotating cutting blade  88  is attached to a free end  90  of the vertical motor shaft  86  and secured to the vertical motor shaft in the conventional manner. 
     When the cutting blade assembly  16  is installed in the two, spaced apart channel members  44  via the rollers  72 , end caps  92  are installed to prevent the cutting blade assembly  16  from rolling out of the two, spaced apart channel members  44 . 
     Retention members  94 , such as compressible springs, are connected to the second retainer member posts  78  are positioned on the second top surface  82  of the motor mount  66 , and the retention member posts. 56  positioned at the fourth end  58  of each of the channel bars,  46 . 
     FIG. 3 shows a top plan view of the mower  10  described in FIGS. 1 and 2. In one method of operation, the attachment frame  12  is pivotally connected to one side of a utility vehicle  8 , such as a four-wheeled motorcycle or other suitable conveyance. The motor  84  is then engaged, causing the cutting blade  88  to rotate. As the utility vehicle  8  and mower  10  move in the A 3  direction, the rotating cutting blade  88  cuts a swath in vegetation. 
     As the utility vehicle continues to move in the A 3  direction, an imaginary point P 1  on an outer periphery  98  of the housing  64  preferably contacts an exterior surface  100  of a post  96 . Continued movement of the utility vehicle  8  in the A 3  direction causes the outer periphery  98  of the housing  64  to travel in a direction toward imaginary point P 2 , along arc length AL 1 . Assuming that the utility vehicle  8  maintains a constant distance from the post  96 , the cutting blade assembly is gradually forced in the A 1  direction as the relative position of the housing  64 , with respect to the post  96 , changes over time from the P 1  position to the P 2  position. Movement of the cutting blade assembly  16  in the A 1  direction is stopped if the movement restriction brackets  80  contact the movement restraint pins  52 . 
     Once the imaginary point P 2  on the outer periphery  98  of the housing  64  is approximately coincident with the post  96 , continued movement of the utility vehicle  8  in the A 3  direction preferably causes a second arc length AL 2  of the outer periphery  98  of the housing  64  to contact the exterior surface  100  of the post  96  in the P 2  to P 3  direction, over time. As contact between the exterior surface  100  of the post  96  and the second arc length AL 2  portion of the outer periphery  98  of the housing  64  continues in the P 2  to P 3  direction over time, and again assuming an approximate static distance between the post  96  and the utility vehicle  8 , the retention members  94  bias the cutting blade assembly  16  housing  64  against the exterior surface  100  of the post  96 . Once the housing  64  clears contact with the post  96 , which in this example would be approximately at imaginary point P 3 , the retention members  94  continue to automatically bias the cutting blade assembly  16  to its approximate pre-contact position with respect to the post  96 , greatly reducing the amount of vegetation which remains uncut between neighboring fence posts. 
     Another feature of the present invention is also shown in FIG.  3 . The first and second articulated joints discussed above allow the attachment frame  12  to pivot with respect to the utility vehicle  8 , and further allow the secondary frame  14  and the cutting blade assembly  16  to pivot with respect to the attachment frame  12 . This configuration allows the cutting blade  88  to adjust to non-planar terrain. 
     As discussed above, the present invention provides a non-complicated device for cutting vegetation between two or more inanimate objects. The cutting blade assembly of the present invention is automatically biased, so there is no need for complex fluid systems. Moreover, the cutting blade is attached to a vertical shaft motor, which eliminates the need for more complex pulley and belt designs. The present invention is also configured to automatically adapt to non-planar terrain, such as culverts or slopes, preferably via the first and second articulation joints. 
     The invention has been described with reference to the preferred embodiment. Obvious modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.