Abstract:
The articulated vehicle of the present invention includes a front frame and a rear frame which are interconnected by a universal coupling joint which is capable of pivoting about a vertical axis and about a horizontal axis. Mower decks may be mounted on the vehicle and raised and lowered by hydraulic cylinders. Hydraulic cylinders are also used to cause articulated movement with respect to the front and rear frames about a vertical axis.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an articulated vehicle and particularly to a vehicle for use over irregular terrain. 
     A primary object of the present invention is the provision of an improved articulated vehicle. 
     A further object of the present invention is the provision of an articulated vehicle which includes a front frame and a rear frame which are interconnected in such a manner that they can pivot with respect to one another about a vertical axis and also about a horizontal axis. 
     A further object of the present invention is the provision of an articulated vehicle which can pass over irregular terrain easily. 
     A further object of the present invention is the provision of an articulated vehicle which can be used to carry mowing machines for use in irregular terrain such as might be encountered on a golf course. 
     A further object of the present invention is the provision of an articulated vehicle which is completely controlled by hydraulics and which can be easily controlled from the operator&#39;s seat. 
     A further object of the present invention is the provision of an articulated vehicle which is economical to manufacture, durable in use and efficient in operation. 
     SUMMARY OF THE INVENTION 
     The articulated vehicle of the present invention includes a front frame having two wheels thereon and a rear frame having two additional wheels thereon. The front frame and the rear frame are interconnected by a coupling assembly which permits the front and rear frames to pivot about a vertical axis with respect to one another and which also permits the front and rear frames to pivot about an axis extending generally in the longitudinal direction of travel of the vehicle. 
     The articulation of the vehicle is accomplished by means of hydraulic cylinders each of which are connected at one end to the front frame of the vehicle and are connected at the opposite end to the coupling member between the front and rear frames of the vehicle. By extending and retracting the cylinders it is possible to cause the vehicle to be articulated about its vertical axis so as to permit the vehicle to turn. 
     One important feature of the present invention is the geometric arrangement of the front wheels with respect to the vertical pivotal axis of the vehicle and the rear wheels with respect to the vertical axis of the vehicle. The front and rear wheels are both equidistant from the vertical axis so that when the vehicle is articulated to turn a corner the rear wheels track in the same path as do the front wheels. This is a particularly helpful feature when the device is used for mowing because it is possible to steer the device closely adjacent to curbed surfaces with the rear wheels following exactly the same path as the front wheels. 
     Mower decks may be mounted on opposite sides of the vehicle and beneath the vehicle so as to provide a very wide cutting swath when the vehicle is used for mowing such as on a golf course. The mower decks are mounted on arms which are pivotal with respect to the vehicle and which are controlled by hydraulic cylinders which permit the raising and lowering of the arms. 
     The operator rides on a platform on the front frame of the vehicle and has at his disposal a plurality of controls which control the articulated movement of the vehicle, the rotation of the wheels of the vehicle, the rotation of the cutting blades on the mower decks, and the raising and lowering of the mower decks with respect to the vehicle. 
     The rear frame of the vehicle is used to support an internal combustion engine which drives a hydraulic pump. The hydraulic pump is connected in an extensive hydraulic circuit for controlling all the various power means in vehicle. Thus, the vehicle is powered entirely by hydraulics. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the vehicle of the present invention. 
     FIG. 2 is a top plan view of the vehicle showing the arrangement of the vehicle frame and wheel supports. 
     FIG. 3 is a top plan view similar to FIG. 2, but showing the arrangement of plurality of mowing decks on the vehicle. 
     FIG. 4 is a sectional view taken along line 4--4 of FIG. 2. 
     FIG. 5 is a plan view taken along line 5--5 of FIG. 4. 
     FIG. 6 is a top plan view similar to FIG. 2, and showing the path of the wheels when the vehicle is articulated. 
     FIG. 7 is a detail view taken along line 7--7 of FIG. 3. 
     FIG. 8 is a detail view taken along line 8--8 of FIG. 3. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, the numeral 10 generally designates the vehicle of the present invention. Vehicle 10 comprises a front vehicle frame 12 and a rear vehicle frame 14 which are supported by front wheels 16 and rear wheels 18, respectively. Referring to FIG. 2, front frame 12 comprises a front frame member 20, a v-shaped rear frame member 22, and two opposite side members 24, 26. Rear frame 14 comprises a front frame member 28, a rear frame member 30, and two opposite side frame members 32, 34. 
     Interconnecting front frame member 12 and rear frame member 14 is a universal connecting assembly 36 which is shown in detail in FIGS. 4 and 5. Connecting assembly 36 includes a cylindrical collar 38 having a clevis 40 welded or otherwise fixed thereto. Clevis 40 includes an upper clevis member 42 and a lower clevis member 44. A vertical pivot pin 46 extends through aligned openings 48, 50 in clevis members 42, 44 and also extends through an elongated cylindrical bore 52 in v-shaped rear frame member 22. A locking nut 54 is threaded over the lower end of pin 46. Pin 46 provides a vertical pivotal axis between the rear frame member 22 of front frame 12 and the connecting assembly 36. 
     Cylindrical collar 38 of connecting assembly 36 includes a cylindrical Teflon bushing 56 mounted therein. Extending through Teflon bushing 56 is a horizontal pivot pin 58 having a head 60 at one end thereof and having a threaded end 62 at the opposite end thereof. A metal washer 64 also surrounds pin 58 and includes a counter bore 66 in which is seated the head 60 of pin 58. As can be seen from FIG. 4, head 60 is recessed axially within counter bore 66. A Teflon washer 68 also surrounds pin 58 and is positioned between metal washer 64 and Teflon bushing 56 so as to permit metal washer 64 to rotate with respect to bushing 56. 
     Pin 58 extends through a pin receiving opening 70 in the forward frame member 28 of rear frame 14. On opposite sides of front frame member 28 and surrounding pin 58 are a pair of Teflon washers 72, 74. Washer 72 permits collar 38 to rotate with respect to front frame member 28, and Teflon washer 74 prevents a nut 76 from frictionally engaging the rearward face of frame member 28. This arrangement provides for a free floating support of pin 58 so that pin 58 is free to rotate with respect to collar 38 and frame member 28. Similarly, collar 38 itself is free to rotate with respect to frame member 28. This provides for free pivotal movement of rear frame 14 with respect to front frame 12 about the horizontal pivotal axis provided by pin 58. 
     Referring to FIG. 5, a pair of ears 78, 80 are welded or otherwise fixed to the outer surface of collar 38 on opposite sides thereof. A pair of hydraulic cylinders 82, 84 are each pivotally connected at one end to ears 78, 80, respectively, and at the opposite ends to ears 86, 88 on the v-shaped sides of front frame member 22 of front frame 12. Extension of piston 82 and retraction of piston 84 causes pivotal movement of front frame 12 with respect to universal connecting assembly 36 about the vertical axis provided by vertical pivot pin 46. This results in front frame 12 pivoting about axis 46 with respect to rear frame 14. As can be seen in FIG. 2, the distance r between the vertical pivot axis 46 and the rear wheels 18 is the same as the distance r between the pivot axis 46 and the front wheels 16. This is an important geometric relationship because when vehicle 10 turns as is illustrated in FIG. 6, the paths of the rear wheels 18 follow exactly the tracks made by front wheels 16. This prevents the rear wheels 18 from short cutting across any corner turned by the vehicle. 
     When the vehicle encounters irregular terrain it is also possible for front frame 12 to pivot about a horizontal axis with respect to rear frame 14, this horizontal axis being provided by the longitudinal axis of pin 60. Thus, a universal articulation of movement is permitted between front frame 12 and rear frame 14. 
     Referring to FIG. 3, the vehicle 10 can be used to support a plurality of mower decks 90 and a under carriage mower deck 92. FIG. 7 illustrates the support for the front mower decks 90 which are supported by arms 94 which are pivoted at 96 and which include a downwardly extending lever arm 98. Connected to the end of lever arm 98 and to the front frame member 20 of front frame 12 are hydraulic cylinders 100 which can be used to raise and lower the decks 90 about horizontal axis 96. 
     Referring to FIG. 8, the rear mower decks 90 are supported by horizontally extending arms 102 which are pivoted to a stub bar 104 about an axis 106. Stub bar 104 is welded or otherwise secured to side frame member 24 of front frame 12. Arms 102 include a lever portion 108 which is connected to a hydraulic cylinder 110 which in turn is connected to stub bar 104 for causing the raising and lowering of arms 102 and mower decks 90. 
     Each mower deck 90 includes a hydraulic motor 112 thereon and deck 92 includes a similar motor 112 thereon. Motors 112 are connected by belts 114 to mower blades (not shown) located on the under surfaces of decks 90. 
     Referring to FIG. 1, rear frame 14 supports an internal combustion engine 116, a hydraulic reservoir 118 and a fuel tank 120. A hydraulic pump (not shown) is driven by engine 116 and is connected by a plurality of hydraulic hoses 122 to a control station 124 on front frame 12. Also mounted on front frame 12 is an operator&#39;s seat 126. A control box 128 includes switches (not shown) for controlling the raising and lowering and the operating of mower decks 90. A foot pedal 130 controls hydraulic motors located at the two wheels 16 for driving them to move the vehicle. A steering control 132 operates the hydraulic cylinders 82, 84 for causing the pivotal movement of front frame 12 with respect to rear frame 14. Thus, it can be seen that all of the mower decks 90, the hydraulic motors 112 thereon, the front wheels 16, the hydraulic cylinders 82, 84, and the cylinders 100, 110, are all hydraulically operated and are driven by the hydraulic pump which in turn is driven by the engine 116. Thus, it can be seen that the device accomplishes at least all of its stated objectives.