Abstract:
A three-point linkage system includes a frame, an upper lift arm assembly pivotally mounted to the frame and a lower lift arm assembly pivotally mounted to the frame. The lower lift arm assembly is linked to the upper lift arm assembly for movement therewith. An actuator is connected to the frame and the upper lift arm assembly to move the upper lift arm assembly and the lower lift arm assembly linked to the upper lift arm assembly relative to the frame. A top link arm is pivotally connected to the upper lift arm assembly such that the top link arm moves with the upper lift arm assembly as the upper lift arm assembly is moved by the actuator. The top link arm including connecting structure for connecting the top link arm to an implement.

Description:
TECHNICAL FIELD 
     The present specification generally relates to linkage systems for vehicles and, more particularly, to three-point linkages for attaching implements to the vehicles. 
     BACKGROUND 
     Three-point hitches are often used to attach implements to a work machine. The three point attachment is a reliable way of joining the implement to the work machine. Often, the three-point hitches include a hitch tube that can be received by a receiver hitch on the work machine, which causes the receiver hitch to be occupied. Other three-point hitch arrangements are desired. 
     SUMMARY 
     In one embodiment, a three-point linkage system includes a frame, an upper lift arm assembly pivotally mounted to the frame and a lower lift arm assembly pivotally mounted to the frame. The lower lift arm assembly is linked to the upper lift arm assembly for movement therewith. An actuator is connected to the frame and the upper lift arm assembly to move the upper lift arm assembly and the lower lift arm assembly linked to the upper lift arm assembly relative to the frame. A top link arm is pivotally connected to the upper lift arm assembly such that the top link arm moves with the upper lift arm assembly as the upper lift arm assembly is moved by the actuator. The top link arm including connecting structure for connecting the top link arm to an implement. 
     In another embodiment, a utility vehicle system includes a utility vehicle including a vehicle frame including upper support beams that extend from front to rear of the utility vehicle on opposite sides of the utility vehicle and an upper transverse support beam that extends between the upper support beams. A hitch receiver is connected to the vehicle frame. A three-point linkage system includes a linkage frame and a hitch tube connected to the linkage frame. The hitch tube is received by the hitch receiver. An attachment is connected to the linkage frame. The attachment includes a clamp that is connected to the upper transverse support beam of the utility vehicle. An upper lift arm assembly is pivotally mounted to the linkage frame. A lower lift arm assembly is pivotally mounted to the linkage frame. The lower lift arm assembly is linked to the upper lift arm assembly for movement therewith. An actuator is connected to the linkage frame and the upper lift arm assembly to move the upper lift arm assembly and the lower lift arm assembly linked to the upper lift arm assembly relative to the linkage frame. A top link arm is pivotally connected to the upper lift arm assembly such that the top link arm moves with the upper lift arm assembly as the upper lift arm assembly is moved by the actuator. The top link arm includes connecting structure for connecting the top link arm to an implement. 
     In another embodiment, a method of providing a three-point linkage for a utility vehicle includes mounting a three-point linkage system to the utility vehicle by inserting a hitch tube connected to a linkage frame of the three-point linkage system into a hitch receiver provided by the utility vehicle and clamping an attachment connected to the linkage frame of the three-point linkage system to a vehicle frame of the utility vehicle; connecting an upper lift arm assembly to an implement, the upper lift arm assembly pivotally mounted to the linkage frame; connecting a lower lift arm assembly to the implement, the lower lift arm assembly pivotally mounted to the linkage frame, the lower lift arm assembly being linked to the upper lift arm assembly for movement therewith; and connecting a top link arm to the implement, the top link arm pivotally connected to the upper lift arm assembly such that the top link arm moves with the upper lift arm assembly. 
     These and additional features provided by the embodiments described herein will be more fully understood in view of the following detailed description, in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which: 
         FIG. 1  is a top, perspective view of an utility vehicle system including a utility vehicle and a three-point linkage system connected thereto according to one or more embodiments described herein; 
         FIG. 2  is rear, perspective view of the utility vehicle system including the utility vehicle and the three-point linkage system connected thereto according to one or more embodiments described herein; 
         FIG. 3  is a top view of the three point linkage system of  FIG. 1  according to one or more embodiments described herein; 
         FIG. 4  is a side view of the three-point linkage system of  FIG. 3  according to one or more embodiments described herein; 
         FIG. 5  is a rear view of the three-point linkage system of  FIG. 3  according to one or more embodiments described herein; 
         FIG. 6  is a side view of the utility vehicle system of  FIG. 1  in operation according to one or more embodiments described herein; 
         FIG. 7  is a top view of the three-point linkage system of  FIG. 3  attached to a front end of the utility vehicle according to one or more embodiments described herein; and 
         FIG. 8  is a section view of the three-point linkage taken along lines  8 - 8  of  FIG. 7  according to one or more embodiments described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments described herein generally relate to three-point linkage systems that can be used to attach an implement to a work machine, such as an utility vehicle. The three-point linkage systems may have a relatively low profile to allow for continued use of devices in proximity to the three-point linkage systems, such as lifting and lowering of a cargo bed on the utility vehicle. 
     Referring to  FIG. 1 , a utility vehicle system  10  includes a utility vehicle  12  and a three-point linkage system  14 . The utility vehicle  12  includes a frame  16 , a body (not shown) and a hydraulic system with pressurized fluid source, generally indicated as element  15 . The frame  16  includes upper support beams  18  and  20  that extend from the rear to the front of the utility vehicle  12  and lower support beams  22  and  24  that also extend from the rear to the front of the utility vehicle  12 . Extending between the upper support beams  18  and  20  is an upper transverse support beam  26  that extends from one side to the other side at the rear of the utility vehicle  12 . Extending between the lower support beams  22  and  24  is a lower transverse support beam  28  that extends from one side to the other side at the rear of the utility vehicle  12 . A receiver hitch  30  is supported by the frame  16  and extends from the rear of the utility vehicle  12 . 
     The three-point linkage system  14  is connected to the utility vehicle  12  at the receiver hitch  30  and at the upper transverse support beam  26  using a pair of turnbuckle attachments  33  and  35 . Referring also to  FIG. 2 , the three-point linkage system  14  includes a stationary frame  32  that includes a top transverse frame bar  34 , a bottom transverse frame bar  36  and vertical side frame bars  38  and  40  that extend vertically between the top and bottom transverse frame bars  34  and  36 . Rigidly connected to the bottom transverse frame bar  36  is a hitch tube  42  ( FIG. 3 ). The hitch tube  42  extends horizontally from the frame  32  generally in the frontward direction. The turnbuckle attachments  33  and  35  are connected directly to the frame  32  (e.g., at the top transverse frame bar  34  and/or the vertical side frame bars  38  and  40 ) using rear mounts  37  and  39 . Pins  41  and  43  may be used to rotatably connect the turnbuckle attachments  33  and  35  to the frame  32 . The turnbuckle attachments  33  and  35  may include clamps  45  and  47  that are sized to fit about the upper transverse support beam  26  to connect the three-point linkage system  14  to the utility vehicle  12 . 
     An upper lift arm assembly  44  and a lower lift arm assembly  46  are pivotally connected to the frame  32  such that they can pivot up and down relative to the frame  32 . Referring to  FIGS. 3-5 , the upper lift arm assembly  44  includes an inner transverse beam  48  that is pivotally connected between the side frame bars  38  and  40  and between the top and bottom transverse frame bars  34  and  36 . A pair of upper lift arms  50  and  52  extend rearward from the inner transverse beam  48  and are rigidly connected thereto at their inner ends  54  and  56  such that they can pivot with the inner transverse beam  48  relative to the frame  32 . An outer transverse beam  58  is connected to outer ends  60  and  62  of the upper lift arms  50  and  52  thereby spanning a gap between the upper lift arms  50  and  52 . In some embodiments, such as shown, the outer transverse beam  58  may have a length that is greater than a distance between the upper lift arms  50  and  52  such that the outer transverse beam  58  extends outwardly beyond the upper lift arms  50  and  52  in the side-to-side direction. Extending rearward of the outer transverse beam  58  at its ends  64  and  66  are outer yoke members  68  and  70  and inner yoke members  72  and  74 . The inner and outer yoke members  72 ,  68  and  74 ,  70  cooperate to receive pins  76  and  78 . The pins  76  and  78  may be used to link the upper lift arm assembly  44  to the lower lift arm assembly  46  using adjustable link arms  80  and  82 . A central mount  84  is located between the inner yoke members  72  and  74 . The central mount  84  is connected directly to the outer transverse beam  58 . The central mount  84  is rigidly connected to the outer transverse beam  58  and may be used to connect both a top link arm  86  and a hydraulic actuator  88  directly to the outer transverse beam  58 . In some embodiments, there may be more than one central mount for connecting the top link arm  86  and the hydraulic actuator  88  directly to the outer transverse beam  58 . A pin  90  may be used to rotatably connect the top link arm  86  to the outer transverse beam  58  and pin  92  may be used to rotatably connect the hydraulic actuator  88  to the outer transverse beam  58 . 
     The lower lift arm assembly  46  includes a pair of lower lift arms  94  and  96  that are linked to both the outer transverse beam  58  and the frame  32 . At inner ends  98  and  100  of the lower lift arms  94  and  96 , the lower lift arms  94  and  96  are pivotally connected at outer surfaces  102  and  104  of the vertical side frame bars  38  and  40 . Rods  106  and  108  may be used to pivotally connect the lower lift arms  94  and  96  to the frame  32 . The lower lift arms  94  and  96  extend in a rearward direction to outer ends  110  and  112 . The lower lift arms  94  and  96  are linked to the outer transverse beam  58  of the upper lift arm assembly  44  using the adjustable link arms  80  and  82 . Referring particularly to  FIG. 5 , the adjustable link arms  80  and  82  may include yoke-type attachment structures  114  and  116  that are used to pivotally link the adjustable link arms  80  and  82  to the lower lift arms  94  and  96  at a location between the ends  98 ,  100  and  110 ,  112 . 
     Referring to  FIG. 5 , the hydraulic actuator  88  is connected directly to the outer transverse beam  58  and the bottom transverse frame bar  36 . In some embodiments, the hydraulic actuator  88  may be connected to the bottom transverse frame bar  36  by a cylinder mount assembly  118  that includes a pin  119  that pivotally connects the hydraulic actuator  88  to the bottom transverse frame bar  36 . While a hydraulic actuator  88  is referred to above, other suitable actuators may be employed such at pneumatic actuators or motor-driven actuators, as examples. A receiver hitch  120  extends rearwardly from the bottom transverse frame bar  36 . The receiver hitch  120  may be provided to receive an additional hitch tube so that the three-point linkage system  14  need not be removed to expose the receiver hitch  30  of the utility vehicle  12 . 
     Referring now to  FIG. 6 , the three-point linkage system  14  is illustrated connected to the utility vehicle  12  as if it was linked to an implement (omitted for clarity). As can be seen, the top link arm  86  and the lower lift arms  94  and  96  each include connection structures  122  and  124  (e.g., openings), respectively, that provide the three-point connection locations for connecting the three-point linkage system  14  to the implement. The implement may include rods or other connection structures that are received by the connection structures  122  and  124  for connection to the three-point linkage system  14 . The hydraulic actuator  88  includes connectors  126  and  128  that connect the hydraulic actuator  88  to the utility vehicle&#39;s hydraulic system  15 . Extending and retracting the rod  130  of the hydraulic actuator  88  lifts and lowers the upper lift arm assembly  44  and the lower lift arm assembly  46  in the direction of arrows  132  due to the linkage between the upper lift arm assembly  44  and the lower lift arm assembly  46 . The lower lift arms  94  and  96  may be used for primary lifting of the implement. The top link arm  86  is connected directly to the upper lift arm assembly  44  and is raised and lowered therewith. The top link arm  86  may also pivot in the direction of arrows  134  relative to the upper lift arm assembly  44 . 
     The three-point linkage system  14  provides a relatively lowered profile that can allow for operation of various utility vehicle systems, such as the cargo bed  136 .  FIG. 6  illustrates the three-point linkage system  14  in a raised position with the cargo bed  136  also in a raised position (e.g., having a raised angle α of greater than 15 degrees). In these raised positions, clearance  138  is provided between the upper lift arm assembly  44  and the lowest point  140  of the cargo bed  136  such that the upper lift arm assembly  44  does not interfere with operation of the cargo bed  136 . 
     Referring now to  FIGS. 7 and 8 , the three-point linkage system  14  may also be attached to a front end of the utility vehicle  12 . In this embodiment, a cross-support  142 , in addition to a receiver hitch  144 , are used to connect the three-point linkage system  14  to the front of the utility vehicle  12 . In particular, the utility vehicle  12  may include a front end connection plate  146  that is used to connect to the cross-support  142 , for example, using fastener bolts  148  or any other suitable connectors. The hitch tube  42  can be received by the receiver hitch  144 . Similar to the rear connection described above, the hydraulic actuator  88  may be connected to the hydraulic system  15  of the utility vehicle  12  for lifting and lowering of the upper lift arm assembly  44  and the lower lift arm assembly  46 . 
     The above-described three-point linkage systems can allow various utility vehicles the capability to operate a variety of implements, such as category 0-1 implements, while still allowing use to their cargo beds due to the low profile of the three-point linkage systems. Exemplary implements include fertilizer spreaders, box blades, boom poles, augers, graders, yard pluggers, aerators, carry alls, movers, etc. The three-point linkage systems may be used on a number of utility vehicles, such as those manufactured by Kubota, John Deere, Polaris, Toro and Kioti. 
     While particular embodiments have been illustrated and described herein, it should be understood that various other changes and modifications may be made without departing from the spirit and scope of the claimed subject matter. Moreover, although various aspects of the claimed subject matter have been described herein, such aspects need not be utilized in combination. It is therefore intended that the appended claims cover all such changes and modifications that are within the scope of the claimed subject matter.