Patent Publication Number: US-9410304-B2

Title: Lift assembly for a work vehicle

Description:
FIELD OF THE INVENTION 
     The present subject matter relates generally to work vehicles and, more particularly, to an improved lift assembly that allows for the loader arms of a work vehicle to be raised and/or lowered along a plurality of different travel paths. 
     BACKGROUND OF THE INVENTION 
     Work vehicles having loader arms, such as skid steer loaders, telescopic handlers, wheel loaders, backhoe loaders, forklifts, compact track loaders and the like, are a mainstay of construction work and industry. For example, skid steer loaders typically include a pair of loader arms pivotally coupled to the vehicle&#39;s chassis that can be raised and lowered at the operator&#39;s command. The loader arms typically have an implement attached to their end, thereby allowing the implement to be moved relative to the ground as the loader arms are raised and lowered. For example, a bucket is often coupled to the loader arm, which allows the skid steer loader to be used to carry supplies or particulate matter, such as gravel, sand, or dirt, around a worksite. 
     Typically, each lift arm is coupled to the loader chassis at a given pivot point and is configured to be raised and lowered by a corresponding lift cylinder. As such, when the lift cylinders are extended and retracted, the loader arms may be raised and lowered, respectively, along a radial or arced path centered at the pivot point defined between the loader arms and the chassis. Such a radial lift path is often adequate for many loader applications but may not be the most desirable in applications where there is a need to alter the lift path of the loader arms to optimize performance for various tasks. For instance, to increase the rated operating capacity of the loader, it is desirable to have a substantially vertical lift path for the loader arms. As a result, manufacturers currently provide loader configurations that include complex four-bar linkages for the loader arms that allow for a substantially vertical lift path to be achieved. However, these loader configurations are restricted to lifting the loader arms along their single, pre-defined vertical lift path and, thus, the ability to alter the lift path of the loader arms for various tasks is lost. 
     Accordingly, an improved lift assembly for a work vehicle that allows for the loader arms of such vehicle to be raised and/or lowered along a plurality of different travel paths to allow for variations in the rated operating capacity, horizontal reach and/or cycle times associated with the loader arms would be welcomed in the technology. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
     In one aspect, the present subject matter is directed to a lift assembly for a work vehicle. The lift assembly may generally include a loader arm extending between a forward end and a rear end and a control arm extending between a first end and a second end. The first end may be coupled to a chassis of the work vehicle at a first pivot point and the second end may be coupled to the rear end of the loader arm at a second pivot point. In addition, the lift assembly may include a lift cylinder coupled between the loader arm and the chassis and a control cylinder extending between an upper end and a lower end, with the upper end being coupled to the control arm and the lower end being coupled to the chassis at a third pivot point. Moreover, the first pivot point may be located rearward of the second pivot point when the control cylinder is at a fully retracted position. 
     In another aspect, the present subject matter is directed to a lift assembly for a work vehicle. The lift assembly may generally include a loader arm extending between a forward end and a rear end and a control arm extending between a first end and a second end. The first end may be coupled to a chassis of the work vehicle at a first pivot point and the second end may be coupled to the rear end of the loader arm at a second pivot point. In addition, the lift assembly may include a lift cylinder coupled between the loader arm and the chassis and a control cylinder extending between an upper end and a lower end, with the upper end being coupled to the control arm and the lower end being coupled to the chassis at a third pivot point. Moreover, the lift cylinder may be coupled to the chassis at a fourth pivot point that is positioned both vertically below and rearward of the third pivot point. 
     In a further aspect, the present subject matter is directed to a method for controlling a lift assembly of a work vehicle. The lift assembly may include a loader arm and a control arm, wherein the control arm extends between a first end coupled to a chassis of the work vehicle at a first pivot point and a second end coupled to the loader arm at a second pivot point. The method may generally include receiving an operator input associated with a selection of a desired travel path for the loader arm, receiving at least one sensor measurement associated with a position of at least one of the loader arm or the control arm and controlling an actuation of at least one of a lift cylinder or a control cylinder of the lift assembly based on the at least one sensor measurement such that a reference point defined on the loader arm is raised or lowered along the desired travel path, wherein the lift cylinder is coupled between the loader arm and the chassis and wherein the control cylinder extends between an upper end coupled to the control arm and a lower end coupled to the chassis at a third pivot point. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
         FIG. 1  illustrates a side view of one embodiment of a work vehicle in accordance with aspects of the present subject matter, particularly illustrating an implement of the work vehicle being located at its lowermost position relative to a driving surface of the vehicle; 
         FIG. 2  illustrates a rear perspective view of the work vehicle shown in  FIG. 1 ; 
         FIG. 3  illustrates a front perspective view of the work vehicle shown in  FIG. 1 , particularly illustrating the implement after it has been raised from its lowermost position via a lift assembly of the vehicle; 
         FIG. 4  illustrates a side view of the work vehicle shown in  FIG. 1  with the implement being raised relative to the vehicle&#39;s driving surface to a first location, particularly illustrating two suitable travel paths that may be used to raise the implement to the first location in accordance with aspects of the present subject matter; 
         FIG. 5  illustrates another side view of the work vehicle shown in  FIG. 1  with the implement being raised relative to the vehicle&#39;s driving surface to a second location, particularly illustrating two suitable travel paths that may be used to raise the implement to the second location in accordance with aspects of the present subject matter; 
         FIG. 6  illustrates a further side view of the work vehicle shown in  FIG. 1 , particularly illustrating one example of a straight vertical travel path along which the loader arms may be raised and lowered in accordance with aspects of the present subject matter; 
         FIG. 7  illustrates a schematic diagram of one embodiment of a control system for controlling a lift assembly of a work vehicle in accordance with aspects of the present subject matter; and 
         FIG. 8  illustrates a flow diagram of one embodiment of a method for controlling a lift assembly of a work vehicle in accordance with aspects of the present subject matter. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
     In general, the present subject matter is directed to an improved lift assembly for a work vehicle. Specifically, in several embodiments, the lift assembly may include a pair of loader arms pivotally coupled to a corresponding pair of control arms, with each control arm being pivotally coupled, in turn, to the chassis of the work vehicle. In addition, the lift assembly may include a pair of lift cylinders for raising and lowering the loader arms and a pair of control cylinders for adjusting the position of a dynamic pivot point defined between the control arms and the loader arms. Specifically, by retracting and/or extending the control cylinders, the control arms may be pivoted about a fixed pivot point defined between the control arms and the chassis, thereby adjusting the relative position of the dynamic pivot point. 
     Such adjustments of the dynamic pivot point may allow for the travel path of the loader arms to be varied as the arms are raised and/or lowered relative to the ground via the lift cylinders. Thus, by carefully controlling the actuation of the control cylinders and the lift cylinders, the loader arms may be raised and/or lowered along a plurality of different travel paths, thereby allowing specific travel paths to be selected and/or tailored to the requirements of the work being performed. For instance, if increased lift capacity is required, the actuation of the control cylinders and the lift cylinders may be controlled in a manner that provides for the forward end of the loader arms (i.e., the end coupled to a suitable implement, such as a bucket) to be raised and/or lowered along a substantially vertical travel path. Alternatively, if increased reach and/or increased lift speed is required, the actuation of the control cylinders and lift cylinders may be controlled in a manner that provides for the forward end of the loader arms to be raised and/or lowered along a more radial or arcuate travel path. Moreover, the use of the control cylinders may also allow for the forward end of the loader arms to be raised and/or lowered along an absolute straight vertical travel path along at least a portion of the vertical distance defined between the vehicle&#39;s driving surface and the maximum lift height for the loader arms. 
     Referring now to  FIGS. 1-3 , one embodiment of a work vehicle  10  is illustrated in accordance with aspects of the present subject matter. Specifically,  FIG. 1  illustrates a side view of the work vehicle  10 , particularly illustrating an implement  12  of the work vehicle  10  being located at its lowermost position relative to a driving surface  22  of the vehicle  10 . Additionally,  FIG. 2  illustrates a rear perspective view of the work vehicle  10  shown in  FIG. 1  and  FIG. 3  illustrates a front perspective of the work vehicle  10  after the implement  12  has been raised from its lowermost position. For purposes of description, the forward direction (indicated by arrow  14  in  FIG. 1 ) and the reverse direction (indicated by arrow  16  in  FIG. 1 ) will be referenced relative to a front end  18  and a rear end  20  of the work vehicle  10 . Thus, for example, a first location on the work vehicle  10  may be considered to be positioned rearward of a second location on the work vehicle  10  if the first location is positioned closer to the rear end  20  of the work vehicle  10  than the second location along a reference plane extending parallel to the driving surface  22 . 
     In the illustrated embodiment, the work vehicle  10  is configured as a skid steer loader. However, in other embodiments, the work vehicle  10  may be configured as any other suitable work vehicle known in the art, such as any other work vehicle including loader arms (e.g., telescopic handlers, wheel loaders, backhoe loaders, forklifts, compact track loaders and/or the like). 
     As shown, the work vehicle  10  includes a pair of front wheels  24 , a pair of rear wheels  26  and a chassis  28  coupled to and supported by the wheels  24 ,  26 . An operator&#39;s cab  30  may be supported by a portion of the chassis  28  and may house various input devices for permitting an operator to control the operation of the work vehicle  10 . In addition, the work vehicle  10  may include an engine (not shown) and a hydrostatic drive unit (not shown) coupled to or otherwise supported by the chassis  28 . 
     It should be appreciated that various components of the work vehicle  10  will be described herein as being coupled to the chassis  28 . As used herein, a component may be “coupled to” the chassis  28  by being directly coupled to a component of the chassis  28  or by being indirectly coupled to a component of the chassis  28  (e.g., via a secondary component). 
     Moreover, as shown in  FIGS. 1-3 , the work vehicle  10  may also include a lift assembly  36  for raising and lowering the implement  12  (e.g., a bucket, fork, blade and/or the like) relative to the driving surface  22  of the vehicle  10 . In several embodiments, the lift assembly  36  may include a pair of loader arms (e.g., a first loader arm  38  and a second loader arm  40 ) pivotally coupled to the implement  12  and a corresponding pair of control arms (e.g., a first control arm  42  and a second control arm  44 ) pivotally coupled between the loader arms  38 ,  40  and the chassis  28 . Specifically, as shown in  FIG. 1 , the loader arms  38 ,  40  may each be configured to extend lengthwise between a forward end  46  and an aft end  48 , with the forward end  46  of each loader arm  38 ,  40  being pivotally coupled to the implement  12  at a forward pivot point  50  and the aft end  48  of each loader arm  38 ,  40  being pivotally coupled to its corresponding control arm  42 ,  44  at a dynamic rear pivot point  52 . Similarly, each control arm  42 ,  44  may extend between a first end  54  and a second end  56 , with the first end  54  being pivotally coupled to the chassis  28  at a fixed pivot point  58  and the second end  56  being pivotally coupled to the aft end  48  of the corresponding loader arm  38 ,  40  at the dynamic pivot point  52 . 
     As particularly shown in  FIG. 2 , in several embodiments, a connector arm  60  may be configured to extend perpendicularly between the control arms  42 ,  44  in order to secure the control arms  42 ,  44  to one another. For example, in one embodiment, the connector arm  60  may have a tube-like configuration and may be configured to be inserted through corresponding openings (not shown) defined in the control arms  42 ,  44 . In such an embodiment, the connector arm  60  may be secured within the openings (e.g., by welding the portions of the connector arm  60  extending through the openings to the control arms  44 ,  44 ) in order to form a frame assembly comprised of the control arms  42 ,  44  and the connector arm  60 . By securing the control arms  42 ,  44  together via the connector arm  60 , it can be ensured that the control arms  42 ,  44  are pivoted simultaneously about the fixed pivot point  58  as the loader arms  38 ,  40  are being raised and/or lowered. 
     In addition, the lift assembly  36  may also include a pair of hydraulic lift cylinders  62  coupled between the chassis  28  and the loader arms  38 ,  40  and a pair of hydraulic tilt cylinders  64  coupled between the loader arms  38 ,  40  and the implement  12 . For example, as shown in the illustrated embodiment, each lift cylinder  62  may be pivotally coupled to the chassis at a lift pivot point  66  and may extend outwardly therefrom so to be coupled to its corresponding loader arm  38 ,  40  at an intermediate attachment location  68  defined between the forward and aft ends  46 ,  48  of each loader arm  38 ,  40 . Similarly, each tilt cylinder  68  may be coupled to its corresponding loader arm  38 ,  40  at a first attachment location  70  and may extend outwardly therefrom so as to be coupled to the implement  12  at a second attachment location  72 . 
     It should be readily understood by those of ordinary skill in the art that lift and tilt cylinders  62 ,  64  may be utilized to allow the implement  12  to be raised/lowered and/or pivoted relative to the driving surface  22  of the work vehicle  10 . For example, the lift cylinders  62  may be extended and retracted in order to pivot the loader arms  38 ,  40  upward and downwards, respectively, about the dynamic pivot point  52 , thereby at least partially controlling the vertical positioning of the implement  12  relative to the driving surface  22 . Similarly, the tilt cylinders  64  may be extended and retracted in order to pivot the implement  12  relative to the loader arms  38 ,  40  about the forward pivot point  50 , thereby controlling the tilt angle or orientation of the implement  12  relative to the driving surface  22 . 
     Moreover, in several embodiments, the lift assembly  36  may also include a pair of control cylinders  74  for adjusting the relative location of the dynamic pivot point  52 , thereby allowing for the travel path of the loader arms  38 ,  40  to be dynamically adjusted as the implement  12  is being raised and/or lowered relative to the drive surface  22 . Specifically, as shown in the illustrated embodiment, the control cylinders  74  may each be configured to extend between a top end  76  and a bottom end  78 , with the top end  76  of each control cylinder  74  being pivotally coupled to its corresponding control arm  42 ,  44  at the dynamic pivot point  52  and the bottom end  78  being pivotally coupled to the vehicle&#39;s chassis  28  at a control pivot point  80 . Alternatively, the top end  76  of each control cylinder  74  may be coupled to the corresponding control arm  42 ,  44  at any other suitable location along the arm&#39;s length, such as at a location between the dynamic pivot point  52  and the fixed pivot point  58 . Regardless, the control cylinders  74  may be extended and retracted in order to adjust the location of the dynamic pivot point  52  in a counter-clockwise direction or a clockwise direction, respectively, about the fixed pivot point  58 . Thus, by controlling the actuation or stroke length of the control cylinders  74 , the loader arms  38 ,  40  may be raised and/or lowered along any number of different travel paths as the lift cylinders  62  as are used to adjust the position of the implement  12  relative to the driving surface  22 . 
     For example,  FIG. 1  illustrates a bounded travel area  82  defining the potential area across which the forward pivot point  50  may be moved using the disclosed lift assembly  36 . Specifically, as shown in  FIG. 1 , the travel area  82  is defined by a first boundary line  83 , a second boundary line  84 , a third boundary line  85  and a fourth boundary line  86 . The first and third boundary lines  83 ,  85  generally define the range of movement for the loader arms  38 ,  40  at the forward pivot point  50  when the control cylinders  74  are being actuated while the lift cylinders  62  are maintained at either their fully retracted position or their fully extended position. For example, when the forward pivot point  50  is located at the lowermost position within the bounded travel area  82  (i.e., at point  87 ), the forward pivot point  50  may be moved along the first boundary line  83  to point  88  by simply actuating the control cylinders  74  from a fully retracted position (at point  87 ) to a fully extended position (at point  88 ) while maintaining the lift cylinders  62  at their fully retracted position. Similarly, the forward pivot point  50  may be moved along the third boundary line  85  from point  89  to point  90  by simply actuating the control cylinders  74  from a fully extended position (at point  89 ) to a fully retracted position (at point  90 ) while maintaining the lift cylinders  62  at their fully extended position. 
     Moreover, the second and fourth boundary lines  84 ,  86  generally define the range of movement for the loader arms  38 ,  40  at the forward pivot point  50  when the lift cylinders  62  are being actuated while the control cylinders  74  are maintained in either their fully extended position or their fully retracted position. For example, to move the forward pivot point  50  from point  88  to point  89 , the lift cylinders  62  may be actuated from a fully retracted position (at point  88 ) to a fully extended position (at point  89 ) while maintaining the control cylinders  74  at their fully extended position. Similarly, to move the forward pivot point  50  from point  87  to point  90 , the lift cylinders  62  may be actuated from a fully retracted position (at point  87 ) to a fully extended position (at point  90 ) while maintaining the control cylinders  74  at their fully retracted position. As such, it should be readily understood that, to move the forward pivot point  50  from the lowermost position defined within the bounded travel area  82  (i.e., at point  87 ) to any other location on or within such area  82 , each control cylinder  74  may be either initially maintained at its fully retracted position (e.g., to raise the forward pivot point  50  along the fourth boundary line  86 ) or initially extended outwardly from its fully retracted position (e.g., to initially move the forward pivot point  50  to any location rearward of the fourth boundary line  86 ). 
     It should be appreciated that, in several embodiments, the positioning of the control arms  42 ,  44  relative to the loader arms  38 ,  40  and/or the relative positioning of the various pivot points  52 ,  58 ,  66 ,  80  may be selected such that the desired travel area  82  is defined for the loader arms  38 ,  40  at the forward pivot point  50 . For example, as shown in the illustrated embodiment, the location of the fixed pivot point  58  may be selected such that the pivot point  58  is positioned rearward of and vertically below the dynamic pivot point  52  when the control cylinders  74  are at their fully retracted positions. As such, each control arm  42 ,  44  may be configured to be angled both forward and upward from its first end  54  to its second end  56  when the control cylinders  74  are at their fully retracted positions. Additionally, in one embodiment, the location of the fixed pivot point  58  may be selected such that the pivot point  58  is still positioned rearward of the dynamic pivot point  52  even when the control cylinders  74  are at their fully extended positions. Moreover, in several embodiments, the location of the control pivot point  80  for each control cylinder  74  may be selected such that the pivot point  80  is located both vertically above and forward of the lift pivot point  66  for each lift cylinder  62 . However, it should be appreciated that, in alternative embodiments, the positioning of the control arms  42 ,  44  relative to the loader arms  38 ,  40  and/or the relative positioning of the various pivot points  52 ,  58 ,  66 ,  80  may be adjusted to provide any other suitable configuration that allows for the loader arms  38 ,  40  to be raised and/or lowered along a plurality of different travel paths in a manner consistent with the disclosure provided herein. 
     Moreover, given the bounded travel area  82  shown in  FIG. 1 , one of ordinary skill in the art should readily appreciate that any number of different travel paths may be achieved within such area  82  by selectively actuating the lift cylinders  62  and the control cylinders  74  as the loader arms  38 ,  40  are being raised and/or lowered relative to the driving surface  22 . For example, as shown in  FIG. 4 , it may be desirable for the implement  12  to be raised to a given height  91  above the vehicle&#39;s driving surface  22  (e.g., such that the forward pivot point  50  is located at point  92 ). In such instance, the loader arms  38 ,  40  may be directed along various different travel paths as the forward pivot point  50  is moved between point  87  and point  92 . For example, as shown in  FIG. 4 , a substantially vertical travel path  93  may be defined between the points  87  and  92 , which may allow for the work vehicle  10  to have an increased lift capacity. Alternatively, a more radial or arced travel path  94  may be defined between the points  87  and  92 , which may allow for the implement  12  to be raised to the desired height  91  in a shorter amount of time than that required for the substantially vertical travel path  93 . 
     Another example of suitable travels paths that may be provided within the bounded travel area  82  is shown in  FIG. 5 . As shown, it may be desirable for the implement  12  to be raised to a certain vertical height  95  while also being capable of extending outwardly a given horizontal distance  96  in order to increase the overall reach of the implement  12  (e.g., to point  97 ). In such instance, similar to the example described above with reference to  FIG. 4 , various different travel paths may be defined between point  87  and point  97 . For instance, as shown, a substantially vertical travel path  98  may defined between the points  87  and  97 , which may allow for increased lift capacity. Alternatively, a more radial or arced travel path  88  may be defined between points  87  and  97 , which may allow for the loader arms  38 ,  40  to be raised and/or lowered in less time. 
     It should be appreciated that the various travel paths  93 ,  94 ,  98 ,  99  shown in  FIGS. 4 and 5  are simply illustrated to provide several examples of suitable travel paths that may be achieved using the disclosed lift assembly  36 . However, one of ordinary skill in the art should readily understand that any number of different travel paths may be defined within the bounded travel area  82  by altering the manner in which the control cylinders  74  and the lift cylinders  62  are actuated as the implement  12  is being raised and/or lowered relative to the driving surface  22 . In addition, it should be appreciated that, as an alternative to the forward pivot point  50 , the bounded travel area  82  for the loader arms  38 ,  40  may be defined relative to any other suitable reference point or location along each loader arm  38 ,  40 . 
     It should also be appreciated that, by adjusting one or more parameters associated with the lift cylinders  62  and/or the control cylinders  74  and/or by adjusting the relative positioning of the various pivot points  52 ,  58 ,  66 ,  80 , the shape and/or size of bounded travel area  82  may be varied significantly. For instance, in a particular embodiment, the bounded travel area  82  may be expanded or shifted rearward such that the forward pivot point  50  may be moved along an absolute straight vertical travel path from the lowermost position  87 . An example of such a lift path is illustrated in  FIG. 6 . As shown, the control cylinders  74  and the lift cylinders  62  may be controlled in a manner that allows the forward pivot point to be raised and lowered along a vertically straight path  300  extending between point  87  and point  302 . To achieve this vertical path  300 , the lift cylinders  62  may, in one embodiment, by configured such that each cylinder  62  is not in its fully retracted position when the forward pivot point  50  is located at the lowermost position  87  (i.e., such that the lift cylinders  62  may be further retracted at point  87 ). Such a configuration may generally allow for the aft boundary of the bounded travel area (e.g., defined by the first and second boundary lines  83 ,  84  shown in  FIGS. 4 and 5 ) to be shifted rearward, thereby accommodating the vertical travel path  300  shown in  FIG. 6 . In such an embodiment, to begin raising the forward pivot point  50  upward from point  87  along the vertical path  300 , the lift cylinders  62  may be initially retracted towards their fully retracted position while the control cylinders  74  are extended until the forward pivot point  50  has reached a given height  304 . Thereafter, the lift cylinders  62  may be extended as the control cylinders  74  are controlled in a manner that allows the forward pivot point  50  to be lifted along the remainder of the vertical path  300 . 
     Additionally, it should be appreciated that, although the work vehicle  10  shown in  FIGS. 1-6  has been described herein as including a pair of control cylinders  74  and a pair of lift cylinders  62 , the work vehicle  10  may, instead, include any number of control cylinders  74  and lift cylinders  62 . For instance, in one embodiment, the work vehicle  10  may only include a single control cylinder  74  and a single lift cylinder  62  for controlling the movement of the loader arms  38 ,  40 . Alternatively, the work vehicle  10  may include a single control cylinder  74  together with a pair of lift cylinders  62  for controlling the movement of the loader arms  38 ,  40  or vice versa. 
     Referring now to  FIG. 7 , a schematic diagram of one embodiment of a control system  100  for controlling the disclosed lift assembly  36  is illustrated in accordance with aspects of the present subject matter. In general, the system  100  will be described herein with reference to the work vehicle  10  and lift assembly  36  described above with reference to  FIGS. 1-6 . However, it should be appreciated by those of ordinary skill in the art that the disclosed system  100  may generally be utilized with work vehicles  10  having any another suitable vehicle configuration and/or any other suitable lift assembly configuration consistent with the disclosure provided herein. 
     As shown, the control system  100  may generally include a controller  102  configured to electronically control the operation of one or more components of the work vehicle  10 , such as the various hydraulic components of the work vehicle  10  (e.g., the lift cylinders  62 , the control cylinders  74  and/or the tilt cylinders  64 ). In general, the controller  102  may comprise any suitable processor-based device known in the art, such as a computing device or any suitable combination of computing devices. Thus, in several embodiments, the controller  102  may include one or more processor(s)  104  and associated memory device(s)  106  configured to perform a variety of computer-implemented functions. As used herein, the term “processor” refers not only to integrated circuits referred to in the art as being included in a computer, but also refers to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit, and other programmable circuits. Additionally, the memory device(s)  106  of the controller  102  may generally comprise memory element(s) including, but are not limited to, computer readable medium (e.g., random access memory (RAM)), computer readable non-volatile medium (e.g., a flash memory), a floppy disk, a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), a digital versatile disc (DVD) and/or other suitable memory elements. Such memory device(s)  106  may generally be configured to store suitable computer-readable instructions that, when implemented by the processor(s)  104 , configure the controller  102  to perform various computer-implemented functions, such as the method  200  described below with reference to  FIG. 8 . In addition, the controller  102  may also include various other suitable components, such as a communications circuit or module, one or more input/output channels, a data/control bus and/or the like. 
     It should be appreciated that the controller  102  may correspond to an existing controller of the work vehicle  10  or the controller  102  may correspond to a separate processing device. For instance, in one embodiment, the controller  102  may form all or part of a separate plug-in module that may be installed within the work vehicle  10  to allow for the disclosed system and method to be implemented without requiring additional software to be uploaded onto existing control devices of the vehicle  10 . 
     In several embodiments, the controller  102  may be configured to be coupled to suitable components for controlling the operation of the various cylinders  62 ,  64 ,  74  of the work vehicle  10 . For example, as shown in  FIG. 7 , the controller  102  may be communicatively coupled to suitable valves  108 ,  110  (e.g., solenoid-activated valves) configured to control the supply of hydraulic fluid to each lift cylinder  62  (only one of which is shown in  FIG. 7 ). Specifically, as shown in the illustrated embodiment, the system  100  may include a first lift valve  108  for regulating the supply of hydraulic fluid to a cap end  112  of each lift cylinder  62 . In addition, the system  100  may include a second lift valve  110  for regulating the supply of hydraulic fluid to a rod end  114  of each lift cylinder  62 . Moreover, the controller  102  may be communicatively coupled to suitable valves  116 ,  118  (e.g., solenoid-activated valves) configured to regulate the supply of hydraulic fluid to each control cylinder  74  (only one of which is shown in  FIG. 7 ). For example, as shown in the illustrated embodiment, the system  100  may include a first control valve  116  for regulating the supply of hydraulic fluid to a cap end  120  of each control cylinder  74  and a second control valve  118  for regulating the supply of hydraulic fluid to a rod end  122  of each control cylinder  74 . Although not shown, it should be appreciated that the controller  102  may be similarly coupled to suitable valves for controlling the supply of hydraulic fluid to each tilt cylinder  64 . 
     During operation, hydraulic fluid may be transmitted to the PRVs  108 ,  110 ,  116 ,  118  from a fluid tank  124  mounted on and/or within the work vehicle  10  (e.g., via a pump (not shown)). The controller  102  may then be configured to control the operation of each valve  108 ,  110 ,  116 ,  118  in order to control the flow of hydraulic fluid supplied to each of the cylinders  62 ,  74 . For instance, the controller  102  may be configured to transmit suitable control commands to the lift valves  108 ,  110  in order to regulate the flow of hydraulic fluid supplied to the cap and rod ends  112 ,  114  of each lift cylinder  62 , thereby allowing for control of a stroke length  126 ,  128  of the piston rod associated with each cylinder  62 . Of course, similar control commands may be transmitted from the controller  102  to the control valves  116 ,  118  in order to control a stroke length  128  of the control cylinders  74 . Thus, by carefully controlling the actuation or stroke length  126 ,  128  of the lift and control cylinders  62 ,  74 , the controller  102  may, in turn, be configured to automatically control the manner in which the loader arms  38 ,  40  are raised and lowered relative to the vehicle&#39;s driving surface  22 , thereby allowing the controller  102  to manipulate the travel path of the loader arms  38 ,  40  as desired. 
     Additionally, as shown in  FIG. 7 , the controller  102  may be communicatively coupled to one or more input devices  130  for providing operator inputs to the controller  102 . Such input device(s)  130  may generally correspond to any suitable input device(s) (e.g., a control panel, one or more buttons, levers and/or the like) housed within the operator&#39;s cab  30  that allows for operator inputs to be provided to the controller  102 . For example, in a particular embodiment, the input device(s)  130  may correspond to a lever(s) and/or any other input device(s) that allows for the operator to transmit suitable operator inputs for manually controlling the position of the loader arms  38 ,  40  and/or implement  12 . In response to such input, the controller  102  may transmit suitable control signals to the appropriate valves in order to control the actuation of the corresponding cylinders. Moreover, as will be described in greater detail below, in several embodiments, a plurality of pre-defined travel paths may be stored within the controller&#39;s memory  106 , such as the travel paths  93 ,  94 ,  98 ,  99  shown in  FIGS. 4-6 . In such embodiments, the input device(s)  130  may correspond to suitable buttons and/or any other input device(s) that allow for the operator to transmit a suitable operator input(s) corresponding to a selection of one of the pre-defined travel paths. Upon receipt of such input(s), the controller  102  may then transmit suitable control signals to the appropriate valves in order to control the corresponding cylinders in a manner that causes the loader arms  38 ,  40  to be raised and/or lowered along the selected travel path. 
     Moreover, as shown in  FIG. 7 , the controller  102  may be communicatively coupled to one or more position sensors  132  for monitoring the position(s) and/or orientation(s) of the loader arms  38 ,  40  and/or the control arms  42 ,  44 . In several embodiments, the position sensor(s)  132  may be configured to monitor the degree of actuation of the lift and/or control cylinders  62 ,  74 , which may provide an indication of the position and/or orientation of the corresponding loader arms  38 ,  40  and/or control arms  42 ,  44 . For instance, the position sensor(s)  132  may correspond to one or more rotary position sensors, linear position sensors and/or the like associated with and/or coupled to the piston rod(s) or other movable components of the cylinders  62 ,  74  in order to monitor the travel distance of such components. In another embodiment, the position sensor(s)  122  may correspond to one or more non-contact sensors, such as one or more proximity sensors, configured to monitor the change in position of such movable components of the cylinders  62 ,  74 . In a further embodiment, the position sensor(s) may correspond to one or more flow sensors configured to monitor the fluid into and/or out of each cylinder  62 ,  74 , thereby providing an indication of the degree of actuation of such cylinder  62 ,  74  and, thus, the location of the corresponding loader arms  38 ,  40  and/or control arms  42 ,  44 . 
     In other embodiments, the position sensor(s)  132  may correspond to any other suitable sensor(s) that is configured to provide a measurement signal associated with the position and/or orientation of the loader arms  38 ,  40  and/or control arms  42 ,  44 . For example, a transmitter(s) may be coupled to a portion of one or both of the loader arms  38 ,  40  and/or one or both of the control arms  42 ,  44  that transmits a signal indicative of the height/position and/or orientation of such arm(s)  38 ,  40 ,  42 ,  44  to a receiver disposed at another location on the vehicle  10 . 
     By monitoring the position and/or orientation of the loader arms  38 ,  40  and/or control arms  42 ,  44  using the measurement signals provided by the sensor(s)  132 , the controller  102  may be configured to regulate the operation of the lift and/or control cylinders  62 ,  74  in a manner that provides for extremely accurate control of the disclosed lift assembly  36 . This may be particularly advantageous in instances in which the operator has requested that the loader arms  38 ,  40  be raised and/or lowered along a selected travel path. For example, upon the receipt of an operator input selecting a given travel path, the controller  102  may verify the exact position of the loader arms  38 ,  40  and/or control arms  42 ,  44  using the sensor measurements. Thereafter, the controller  102  may automatically adjust the position of the loader arms  38 ,  40  and/or control arms  42 ,  44 , if necessary, in order to properly position the loader arms relative to the selected travel path (e.g., by moving the loader arms  38 ,  40  and/or control arms  42 ,  44  such that the forward pivot point  50  is positioned on the selected travel path). Moreover, the controller  102  may be configured to continuously monitor the position of the loader arms  38 ,  40  and/or control arms  42 ,  44  as the lift and/or control cylinders  62 ,  74  are being actuated in order to ensure that the actual travel path taken by the loader arms  38 ,  40  corresponds to the selected travel path. 
     It should be appreciated that the controller  102  may also be communicatively coupled to any other suitable sensors for monitoring one or more operating parameters of the work vehicle  10 . For example, in a particular embodiment, the controller  102  may be coupled to one or more load sensors  134  for monitoring the load weight of any external loads applied through the loader arms  38 ,  40  via the implement  12 . Such load monitoring may assist the controller  102  in determining whether an operator-selected travel path is appropriate given the current loading conditions of the work vehicle  10 . For example, if the operator selects a radial travel path for raising the implement  12  to a given height above the driving surface  22 , the controller  102  may be configured to utilize the load measurements provided by the sensor(s)  134  to determine whether the operator-selected path or a different travel path should be used to maintain stability of the work vehicle  10 . For instance, if the load weight exceeds a given threshold, the controller  102  may determine that a more vertical travel path should be used to raise the implement to the selected height in order to avoid vehicle tipping. In such instance, the controller  102  may be configured to automatically adjust the travel path used for the loader arms  38 ,  40  to the more appropriate travel path. In addition, or as an alternative thereto, the controller  102  may be configured to provide the operator with a notification (e.g., an audible or visual notification) that the selected travel path is not appropriate given the current operating conditions. 
     Referring now to  FIG. 8 , a flow diagram of one embodiment of a method  200  for controlling a lift assembly of a work vehicle is illustrated in accordance with aspects of the present subject matter. In general, the method  200  will be described with reference to the work vehicle  10 , lift assembly  36  and system  100  described above with reference to  FIGS. 1-8 . However, it should be appreciated by those of ordinary skill in the art that the disclosed method  200  may generally be utilized to control any suitable lift assembly included within a work vehicle having any suitable configuration and/or any suitable control system. In addition, although  FIG. 8  depicts steps performed in a particular order for purposes of illustration and discussion, the methods discussed herein are not limited to any particular order or arrangement. One skilled in the art, using the disclosures provided herein, will appreciate that various steps of the methods disclosed herein can be omitted, rearranged, combined, and/or adapted in various ways without deviating from the scope of the present disclosure. 
     As shown in  FIG. 8 , at ( 202 ), the method  200  includes receiving an operator input associated with a selection of a desired travel path for the loader arms of the work vehicle. For example, as indicated above, one or more pre-defined travel paths may be stored within the controller&#39;s memory  106 . In such an embodiment, the input device(s)  130  provided within the vehicle&#39;s cab  20  may be used to transmit a suitable operator input(s) to the controller  102  that is associated with the selection of one of the pre-defined travel paths. 
     In addition to such pre-defined travel paths, or as an alternative thereto, one or more customized travel paths may be created and stored within the controller&#39;s memory  106 . For example, in one embodiment, a control panel of the work vehicle  10  may provide a means (e.g., a display with a suitable operator interface) for allowing an operator to define a customized travel path for the loader arms  38 ,  40 , such as by creating any suitable travel path extending within the bounded travel area  82  associated with the disclosed lift assembly  36 . In such an embodiment, the customized travel path may be stored within the controller memory  106  and may be subsequently selected by the operator as the desired travel path to be executed by the controller  102 . 
     Additionally, at ( 204 ), the method  200  includes receiving at least one sensor measurement associated with a position of the loader arms and/or the control arms of the work vehicle. For example, as indicated above, the controller  102  may be communicatively coupled to one or more position sensors  132  for monitoring the position of the loader arms  38 ,  40  and/or the control arms  42 ,  44 . Thus, based on the signals provided by the sensor(s)  132 , the controller  132  may be configured to accurately determine the position of the loader arms  38 ,  40  and/or the control arms  42 ,  44 . 
     Moreover, at ( 206 ), the method  200  includes controlling an actuation of the lift cylinders and/or the control cylinders based on the sensor measurement(s) such that a reference point(s) defined on the loader arms is raised or lowered along the desired travel path selected by the operator. Specifically, as indicated above, the controller  102  may be configured to control the actuation or stroke length  126 ,  128  of the lift cylinders  38 ,  40  and/or the control cylinders  40 ,  42  in order to achieve a plurality of different travel paths within a given travel area  82  associated with the disclosed lift assembly  36 . Accordingly, upon receipt of the operator&#39;s selection, the controller  102  may control the actuation of the lift cylinders  38 ,  40  and/or the control cylinders  40 ,  42  in a manner that causes a given reference point on the loader arms (e.g., the forward pivot point  50 ) to be raised or lowered along the desired travel path. In doing so, the controller  102  may be configured to utilize the sensor measurements in order to move the reference point to a location on the desired travel path and/or to verify that the reference point is being moved along the desired travel path as it is being raised or lowered. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.