Abstract:
A backhoe control pattern selection arrangement is provided for a backhoe controlled by two control levers. The two levers are operatively connected to hydraulic systems that operate the boom and crowd hydraulic cylinders. An electrically operated valve block is electrically connected to a source of power and to a control switch, and hydraulically connected to the hydraulic systems. Changing the state of the control switch actuates the valve block and modifies the hydraulic systems to reverse the correspondence between the control levers and the boom and crowd functions.

Description:
TECHNICAL FIELD OF THE INVENTION  
       [0001]     The present invention relates to work vehicles having excavating buckets, such as backhoes and excavators. Particularly, the invention relates to work vehicles having excavating buckets that control movement of said excavating bucket through the use of two control levers or joysticks.  
       BACKGROUND OF THE INVENTION  
       [0002]     In operating a work vehicle, such as a backhoe, the operator controls a plurality of work operations through manipulating various control levers that control the positioning of hydraulic control valves. The hydraulic control valves in turn regulate the flow of hydraulic fluid to hydraulic cylinders that manipulate the work implement. When operating the backhoe, the operator turns his seat to face rearward. The operator uses control levers to manipulate the boom relative to the tractor, the dipperstick relative to the boom and the bucket relative to the dipperstick.  
         [0003]     On some backhoes the operator controls the backhoe by operating two control levers. Such a backhoe is disclosed in U.S. Pat. No. 6,481,950, herein incorporated by reference. The control levers extend upwardly through a control console located in the rear of the operators cab. The control levers are operatively coupled to a control linkage that manipulates hydraulic control valves in response to movement of the control lever. In the above described control configuration, each control lever controls two hydraulic control valves. Each hydraulic control lever controls one backhoe function by extending and retracting the appropriate hydraulic cylinder or cylinders.  
         [0004]     In one control configuration, fore-and-aft movement of the left hand control lever lowers and raises the boom. This movement is sometimes referred to as “boom.” Side-to-side movement of the left hand control lever moves the boom side-to-side. This movement is sometimes referred to as “swing.” Fore-and-aft movement of the right hand control lever pivots the dipperstick relative to the boom. These movements are sometimes referred to as “crowd.” Side-to-side movement of the right hand control lever curls and uncurls the bucket relative to the dipperstick. This movement is sometimes referred to as “curl” or “bucket.” This overall operating pattern is referred to as a “backhoe pattern” as shown in  FIG. 5 .  
         [0005]     On other backhoes, the operator controls the backhoe by operating two control levers, but the control functions corresponding to the fore and aft movements of the right and left control levers are reversed. In this control configuration, fore-and-aft movement of the right hand control lever lowers and raises the boom. Side-to-side movement of the right hand control lever remains the same, it curls and uncurls the bucket relative to the dipperstick. Fore-and-aft movement of the left hand control lever pivots the dipperstick relative to the boom. Side-to-side movement of the left hand control lever remains the same, it moves the boom side-to-side. This overall operating pattern is referred to as an “SAE pattern” or “excavator pattern” as shown in  FIG. 5 .  
         [0006]     Although it is possible to purchase a backhoe with the operating pattern of choice, the operating pattern cannot be easily changed in the field. Furthermore, some backhoe owners employ several operators who share the use of one backhoe and each operator may be accustomed to a different operating pattern.  
         [0007]     Some heretofore known backhoes have had the capability to switch between patterns. But such switching requires the operator to leave the vehicle cab and, using a wrench, loosening a retaining bolt, turning a switch lever and then retightening the retaining bolt, to switch patterns. The switch lever is located behind a rear tire in a location exposed to dirt and mud.  
         [0008]     The present inventors have recognized that to increase the utility of a work vehicle, it would be advantageous if different operators accustomed to different operating patterns of the work vehicle controls could select their preferred control pattern easily and quickly. The present inventors have recognized that it would be advantageous to provide a pattern switching arrangement that was more easily operable without requiring an operator to leave the operator&#39;s cab to make a pattern switch and without requiring the use of a tool to switch patterns.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention provides an electrical/hydraulic system on a work vehicle that is usable by an operator to easily change control patterns of dual control levers that manipulate a work implement.  
         [0010]     The present invention provides a control arrangement for controlling the operation of a work implement carried on a work vehicle. The arrangement includes a first control lever, a first hydraulic system, and a first hydraulic cylinder. The first control lever is operatively connected to the first hydraulic system. The first control lever is arranged to be moved by an operator alternately in a first direction or in a second direction, to control two-way movement of the first hydraulic cylinder by routing pressurized hydraulic fluid from the first hydraulic system to a respective extend or retract port of the first hydraulic cylinder.  
         [0011]     The arrangement also includes a second control lever, a second hydraulic system, and a second hydraulic cylinder. The second control lever is operatively connected to the second hydraulic system. The second control lever is arranged to be moved by an operator alternately in a third direction or in a fourth direction, to control two-way movement of the second hydraulic cylinder by routing pressurized hydraulic fluid from the second hydraulic system to a respective extend or retract port of the second hydraulic cylinder.  
         [0012]     The first and second hydraulic cylinders are configured and arranged to move or pivot different portions of a work implement of a work vehicle.  
         [0013]     The arrangement also includes a control switch, at least one electrically operated valve block, and third and fourth hydraulic systems. In the preferred embodiment, the third and fourth hydraulic systems are comprised of a reconfiguration of the components that comprise the first and second hydraulic systems. The electrically-operated valve block is electrically connected to a source of power and to the control switch, and hydraulically connected to the first and second hydraulic systems such that changing the state of the control switch charges the state of the electrically operated valve block to operatively connect the first and second control levers to the third and fourth hydraulic systems respectively.  
         [0014]     When the control switch changes the state of the electrically operated valve block, the first control lever is arranged to be moved by an operator alternately in the first direction or in the second direction, to control two-way movement of the second hydraulic cylinder by routing pressurized hydraulic fluid from the third hydraulic system to a respective extend or retract port of the second hydraulic cylinder. The second control lever is arranged to be moved by an operator alternately in the third direction or in the fourth direction, to control two-way movement of the first hydraulic cylinder by routing pressurized hydraulic fluid from the fourth hydraulic system to a respective extend or retract port of the first hydraulic cylinder.  
         [0015]     Preferably the first and second directions are opposite directions, and the third and fourth directions are opposite directions.  
         [0016]     The arrangement can include a third hydraulic cylinder arranged to move or pivot a third portion of the implement, and a fourth hydraulic cylinder arranged to move or pivot a fourth portion of the implement. The first control lever is operatively connected to either the first hydraulic system or the third hydraulic system. When the first control lever is operatively connected to either the first hydraulic system or the third hydraulic system, the first control lever is arranged to be moved by an operator alternately in a fourth direction or in a fifth direction that are different from the first and second directions, to control two-way movement of the third hydraulic cylinder by routing pressurized hydraulic fluid from either the first hydraulic system or the third hydraulic system to a respective extend or retract port of the third hydraulic cylinder. The second control lever is operatively connected to either the second or the fourth hydraulic system. When the second control lever is operatively connected to either the second hydraulic system or the fourth hydraulic system, the second control lever is arranged to be moved by an operator alternately in a seventh direction or in an eighth direction that are different from the third and fourth directions, to control two-way movement of the fourth hydraulic cylinder by routing pressurized hydraulic fluid from either the second hydraulic system or the fourth hydraulic system to a respective extend or retract port of the fourth hydraulic cylinder. The fifth and sixth directions are opposite directions and the seventh and eighth directions are opposite directions, and the fifth direction is perpendicular to the first direction and the seventh direction is perpendicular to the third direction.  
         [0017]     The control switch is located within an operator&#39;s cab of the work vehicle, preferably wherein an operator can actuate the switch while seated in the operator&#39;s cab.  
         [0018]     The electrically operated valve block comprises at least one solenoid valve, preferably two solenoid valves, each having a spool that is shifted by electrical power routed through the control switch.  
         [0019]     The first hydraulic system comprises at least one first pilot operated valve hydraulically connected to a first spool valve that is hydraulically connected to the extend and retract ports of the first hydraulic cylinder. The third hydraulic system comprises the at least one first pilot operated valve hydraulically connected to a second spool valve that is hydraulically connected to the extend and retract ports of the second hydraulic cylinder. The at least one first pilot operated valve is mechanically adjusted by the first control lever.  
         [0020]     The second hydraulic system comprises at least one second pilot operated valve hydraulically connected to the second spool valve that is hydraulically connected to the extend and retract ports of the second hydraulic cylinder. The fourth hydraulic system comprises the at least one second pilot operated valve hydraulically connected to the first spool valve that is hydraulically connected to the extend and retract ports of the first hydraulic cylinder. The at least one second pilot operated valve is mechanically adjusted by the second control lever.  
         [0021]     The invention is advantageously applied to a backhoe having a swing frame, a boom, a dipperstick and a bucket. The swing frame is pivotally mounted to a supporting structure of a backhoe about a vertical pivot axis. The boom is pivotally coupled to the swing frame about a horizontal pivot axis. The dipperstick is pivotally mounted to the boom about a horizontal axis. The bucket is pivotally mounted to the dipperstick about a horizontal axis. The first hydraulic cylinder is connected between the boom and the swing frame. The second hydraulic cylinder is connected between the dipperstick and the boom. The third hydraulic cylinder is connected between the supporting structure and the swing frame. The fourth hydraulic cylinder is connected between the bucket and the dipperstick.  
         [0022]     The present invention provides a control pattern selection arrangement for a work vehicle such as a backhoe loader employing two control levers. The arrangement permits an easy and quick control pattern change by an operator without leaving the operator&#39;s cab and without the use of a tool.  
         [0023]     Numerous other advantages and features of the present invention will be become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]      FIG. 1  is a rear perspective view of a backhoe loader having a cutaway rear window, illustrating left and right control levers on a control console;  
         [0025]      FIG. 2  is a fragmentary perspective view of inside an operator&#39;s cab of the work vehicle of  FIG. 1 ;  
         [0026]      FIG. 3  is a fragmentary, schematic sectional view of one control lever;  
         [0027]      FIG. 4  is a schematic view of the hydraulic control of the backhoe functions of the backhoe loader of  FIG. 1 ;  
         [0028]      FIG. 5  is a diagrammatic plan view showing the functions of movement of the left and right control levers;  
         [0029]      FIG. 6  is a schematic view of a portion of  FIG. 4  in a backhoe select configuration; and  
         [0030]      FIG. 7  is a schematic view of a portion of  FIG. 4  in an excavator select configuration. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0031]     While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.  
         [0032]     The work vehicle  10  illustrated in  FIG. 1  is a backhoe loader. The work vehicle  10  is provided with a supporting structure  12  and ground engaging means  14  comprising wheels which support and propel the supporting structure  12 . Although the ground engaging means  14  of the illustrated embodiment are wheels, the present invention could also be used on tracked work vehicles having steel or rubber tracks. The supporting structure  12  is provided with two work implements, a backhoe  16  and a loader  18 .  
         [0033]     The loader is mounted to the front of the supporting structure  12  and comprises lift arms  20 , only one shown, and a bucket  22 . The lift arms  20  are provided with lift arm hydraulic cylinders  24 , only one shown, for lifting the arms  20  relative to the supporting structure  12 . The bucket  22  is pivotally mounted to the end of the lift arms  20 . Bucket  22  is provided with a bucket-tilt hydraulic cylinder  26  for tilting the bucket  22  relative to the lift arms  20 .  
         [0034]     The backhoe  16  is mounted to the rear of the supporting structure  12  and comprises a swing frame  21 , a boom  23 , a dipperstick  25  and a bucket  27 . The swing frame  21  is pivotally mounted to the supporting structure  12  about a vertical pivot axis. Swing frame hydraulic cylinders  29 , one on each side, only one visible, swing the swing frame  21 . The boom  23  is pivotally coupled to the swing frame about a horizontal pivot and is raised and lowered by a hydraulic cylinder  30  (not visible in  FIG. 1 ) internally mounted in the boom  23 . The dipperstick  25  is pivotally mounted to the boom about a horizontal axis and is pivoted relative to the boom by dipperstick hydraulic cylinder  31 . The bucket  27  is curled and uncurled relative to the dipperstick by bucket hydraulic cylinder  33 .  
         [0035]     Hydraulic control spools control the extension and retraction of the hydraulic cylinders. The hydraulic control spools are opened and closed by pilot operated control mechanisms located inside operator&#39;s cab  35 . Left and right side consoles  32   a ,  32   b  are located in the operator&#39;s cab on opposite lateral sides of an operator&#39;s seat  32   c . The control mechanisms are provided with two control levers  34  and  36  extending upwardly from the consoles  32   a ,  32   b.    
         [0036]     Each control lever  34  and  36  controls two functions by selectively positioning two hydraulic control spools described below. The control levers  34  and  36  can be moved in two orthogonal directions or control arcs, fore-and-aft and side-to-side. For example, according to the “backhoe pattern”, moving the left-hand control lever  34  fore-and-aft lowers and raises the boom  23  by extending and retracting the internally mounted hydraulic cylinder  30 . Moving left-hand control lever  34  side-to-side pivots the swing frame  21  by extending and retracting swing frame hydraulic cylinders  29 .  
         [0037]      FIG. 2  illustrates the control lever  34  extending upwardly from the console  32   a . The lever  34  has a handle  34   a  mounted on a rod  34   b  and a flexible boot  34   c  surrounding the rod  34   b . The lever  36  is identically configured, extending from the console  32   b . To the left of the console  32   a  is a control panel  32   d . Two stabilizer control levers  38   a ,  38   b  extend upwardly from the panel  32   d . A pattern selector switch  39  is arranged on the panel  32   d . An operator can reach and change the state of the switch  39  while seated on the seat  32   c  in the operator&#39;s cab  35 . The switch is preferably a two position rocker switch marked with two indicia of selectable patterns.  FIG. 2  simply indicates “B” and “E”, as indicia for the backhoe and excavator patterns. A graphic pictorial of a backhoe and an excavator can be used as indicia for instant recognition by an operator.  
         [0038]     Two pilot control valve assemblies  40 ,  42  (valve assembly  40  shown schematically in  FIG. 2 ), corresponding to the control levers  34 ,  36  respectively, are used to control backhoe functions. The pilot control valve assemblies  40 ,  42  are located inside the respective boots  34   c  of the levers  34 ,  36  and partially inside the consoles  32   a ,  32   b.    
         [0039]      FIG. 3  illustrates the pilot control valve assembly  40 , the control valve assembly  42  being identically configured. Each control valve assembly includes four plunger assemblies  43 , one for each direction of each function. Each plunger assembly corresponds to one valve spool  232 ,  234 ,  236 ,  238  as described below.  
         [0040]     In neutral, with no other functions activated, return spring  44  holds the metering spool  49  closed. This blocks pressurized fluid from entering the work ports, allowing fluid to return to tank.  
         [0041]     During operation, pilot pressure fluid from the pilot control manifold valve enters the pilot control valve at pressure port  52 . Wobble plate  61  depresses plunger  62  contacting spring guide  63 . The spring guide compresses both return spring  44  and metering (pressure control) spring  65 . The compressed springs move metering spool  49  down to a metering position allowing fluid to flow out the connected workport. As workport pressure builds to meet spring force the metering spool moves between neutral and metered position maintaining commanded pressure. The pilot control valve assemblies  40 ,  42  are heretofore known as commercially available on the JOHN DEERE Models 310SG, 410G or 710G loader backhoes, available from Deere &amp; Company, of Moline, Ill., USA.  
         [0042]      FIG. 4  illustrates a hydraulic control system according to the invention. Except for the improvements set forth in the present invention, the hydraulic system is conventional and available on the JOHN DEERE Models 310SG, 410G or 710G loader backhoes. A more complete description of a like hydraulic system to control a hydraulic implement using pilot operated spool valves is described in U.S. Pat. No. 4,898,078, herein incorporated by reference.  
         [0043]     Pressurized hydraulic fluid is provided via a line  96  to a fluid pressure reduction system  100 . Hydraulic fluid having a reduced pressure is directed from pressure reduction system  100  to pilot control valve assemblies  40 ,  42  ( FIG. 3 ), through supply line  140 . Hydraulic fluid is returned from the pilot control assemblies  40 ,  42  to system  100  through return line  144 .  
         [0044]     Pressurized hydraulic fluid is directed to the working circuit through hydraulic line  150 . The backhoe circuit comprises backhoe control valve  204  having four pilot controlled directional control spools  206 ,  208 ,  210  and  212 . The directional control spools control the movement of the four hydraulic actuators, which include boom swing cylinders  29 , boom-lift cylinder  30 , dipperstick pivot cylinder  31  and bucket-tilt cylinder  33 . All the control spools are positioned by the pilot control valve assemblies  40 ,  42 .  
         [0045]     The pilot control valve assemblies  40 ,  42  are hydraulically connected to the cylinders  30  and  31  through a pattern select valve  220 . The pattern select valve is actuated to select either a “backhoe pattern” or an “excavator pattern” as described below.  FIG. 4  shows the valve  220  in a state corresponding to a backhoe pattern.  
         [0046]     The two pilot control valve assemblies  40 ,  42  hydraulically control the positioning of control spools  206 ,  208 ,  210 ,  212 . Control spools  206 ,  208 ,  210 ,  212  are four-way, three position directional control spools. The control system provides hydraulic inputs to the sides of the control spools  206 ,  208 ,  210 ,  212  for hydraulically shifting the control spools. Hydraulic fluid from the pressure reduction system  100  is directed to the pilot control system through line  228  and hydraulic fluid is returned to the system  100  through return line  144 .  
         [0047]     The left side pilot control valve assembly  40  is provided with four, two-position valve spools  232 ,  234 ,  236  and  238  that are arranged in two opposed pairs. In the backhoe pattern, the first opposed pair of valve spools  232 ,  234  controls the positioning of boom-lift control spool  208 , whereas the second opposed pair of valve spools  236 ,  238  control the positioning of the swing control spool  206 . Fluid from line  228  is a shared hydraulic supply line to which each of the four valve spools  232 ,  234 ,  236 ,  238  is fluidly coupled. In addition, each of the four valve spools is fluidly coupled to return line  144 .  
         [0048]     The positioning of the four valve spools is manually controlled by the operator through a joystick arrangement, the control lever  34 . As the control lever  34  is moved backward, spool  234  is positioned to direct hydraulic fluid from shared hydraulic line  228  to the right side of control valve spool  208 . At the same time, valve spool  232  fluidly couples the left side of control spool  208  to return line  144 . In this way, control spool  208  is moved to the left so that hydraulic fluid from supply line  96  retracts boom lift cylinder  30 , raising the boom. If the lever  34  is moved forward, the roles of the valve spools  232 ,  234  are reversed and the control spool  208  shifts to the right and the boom lift cylinder  30  extends, lowering the boom. The swing cylinders  29  are controlled in a similar manner, by the left and right movement of the control lever  34 . A left movement of the control lever  34  causes the valve spool  236  to direct hydraulic fluid from shared hydraulic line  228  to the right side of swing control spool  206  and at the same time the valve spool  238  fluidly couples the left side of the control spool  206  to the shared return line  144 . The cylinders  29  move in opposite directions to swing the boom to the left. If the lever  34  is instead moved to the right, the roles of the valve spools  236 ,  238  are reversed, and the swing control spool  206  is shifted to the right and the cylinders  29  move in opposite directions to swing the boom to the right.  
         [0049]     The right side pilot control valve assembly  42  is provided with four, two-position valve spools  242 ,  244 ,  246  and  248  that are arranged in two opposed pairs. In the backhoe pattern, the first opposed pair of valve spools  242 ,  244  controls the positioning of crowd control spool  212 , whereas the second opposed pair of valve spools  246 ,  248  control the positioning of the bucket or curl control spool  210 . Line  228  is a shared hydraulic supply line to which each of the four valve spools  242 ,  244 ,  246 ,  248  is fluidly coupled. In addition, each of the four valve spools  242 ,  244 ,  246 ,  248  is fluidly coupled to return line  144 .  
         [0050]     The positioning of the four valve spools  242 ,  244 ,  246 ,  248  is manually controlled by the operator through a joystick arrangement, the control lever  36 . As the control lever  36  is moved backward, spool  244  is positioned to direct hydraulic fluid from shared hydraulic line  228  to the right side of control valve spool  212 . At the same time, valve spool  242  fluidly couples the left side of control spool  212  to return line  144 . In this way, control spool  212  is moved to the left so that hydraulic fluid from supply line  96  retracts crowd cylinder  31 , raising the dipperstick  25 . If the lever  36  is moved forward, the roles of the valve spools  242 ,  244  are reversed and the control spool  212  shifts to the right and the crowd cylinder  31  extends, lowering the dipperstick  25 . The bucket cylinder  33  is controlled in a similar manner, by the left and right movement of the control lever  36 . A left movement of the control lever  36  causes the valve spool  246  to direct hydraulic fluid from shared hydraulic line  228  to the left side of bucket control spool  210  and at the same time the valve spool  248  fluidly couples the right side of the control spool  210  to the shared return line  144 . The cylinder  33  extends to curl in the bucket  27 . If the lever  36  is instead moved to the right, the roles of the valve spools  246 ,  248  are reversed, and the bucket control spool  210  is shifted to the left and the cylinder  33  retracts to curl out the bucket  27 .  
         [0051]     The pattern select valve  220  is used to switch from the backhoe pattern of  FIGS. 4 and 6  to the excavator pattern of  FIG. 7 . To accomplish the switch, the location of the backhoe boom and crowd functions as between the levers  34 ,  36 , are switched.  
         [0052]     The pattern select valve  220  can include two, two-position four-way solenoid operated valves  260 ,  262 . These valves are controlled by the two-position pattern select switch  39 . The switch  39  is connected to a source of electrical power  270  from the vehicle electrical system. The source of electrical powers is simplified in the schematic as a battery, but could utilize a relay, a fuse and/or other electronics as known for vehicle electrical switching.  
         [0053]     As shown in  FIG. 6 , with pattern select switch  39  in backhoe position “B”, both solenoid valves  260 ,  262  are de-energized and solenoid springs  272  shift the solenoid valves to the right. This configures the hydraulic system to control boom lift cylinder  30  with the left control lever  34  and crowd cylinder  31  with the right control lever  36 .  
         [0054]     As shown in  FIG. 7 , with pattern select switch  39  in excavator position “E”, both solenoid valves are energized and act to shift the solenoid valves  260 ,  262  to the left, overcoming force from the solenoid springs  272 . This directs oil to control the boom lift cylinder  30  with the right control lever  36  and the crowd cylinder  31  with the left control lever  34 .  
         [0055]     From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.