Patent Publication Number: US-7584941-B2

Title: Method and apparatus for operating an implement for a machine

Description:
CLAIM FOR PRIORITY 
   The present application claims priority from U.S. Provisional Application Ser. No. 60/882,978, filed Dec. 31, 2006, which is fully incorporated herein. 

   TECHNICAL FIELD 
   This disclosure relates generally to a method and apparatus for operating an implement for a machine, and more particularly, to a method and apparatus for operating a winch for a machine having a first and a second operator input. 
   BACKGROUND 
   Machines such as skid steer loaders, multi-terrain loaders, track-type tractors, tracked loaders, etc., generally have an engine powering some type of hydraulic system for propelling the machine or providing hydraulic power to linkages. These machines may also use the engine to power an auxiliary implement, such as a winch. Typically, the linkage and the auxiliary implement are controlled by an operator input, such as a joystick, lever, or switch positioned within an operator cab. The operator cab may include a rollover protective structure (ROPS) and/or a falling object protective structure (FOPS). 
   While the use of an operator input while in the operator cab is desired for most applications, some applications may necessitate some degree of remote control. For example, winches are frequently used for extracting tree stumps by means of a line secured around the trunk and attached to the winch. When an unassisted operator performs a tree extraction using a winch, the operator must frequently leave the cab to extend the winch and secure the line about a tree, then climb back up into the cab to retract the line. If the operator did not properly secure the line, or if the line was caught on an obstruction, the line may fall off the tree when the line is retracted, requiring the operator to leave the cab and repeat the process. 
   The present disclosure is directed to overcoming one or more of the problems as set forth above. 
   SUMMARY 
   In one aspect of the present disclosure, a machine is provided. The machine has a body, a pump, an implement, an operator station, a first operator input device, and a second operator input device. The pump is mounted to the body and has a first operating range. The implement is mounted to the body and coupled to the pump. The operator station is positioned on the body. The first operator input device is located within the operator station and operable to control the implement over the first operating range and the second operator input device is positioned external to the operator station and operable to control the implement over a second operating range. The second operating range is less than the first operating range. 
   In another aspect of the present disclosure, a method of operating an implement for a machine is provided. The machine has a body, a pump mounted to the body that powers the implement over a first operating range, an operator station positioned on the body, a first operator input device located within the operator station, and a second operator input device positioned external to the operator station. The method includes the step of operating the implement over the first operating range when a command from the first operator input device is received. The method also includes the step of operating the implement over a second operating range when a command from the second operator input device is received, wherein the second operating range is less than the first operating range. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagrammatic illustration of a machine suitable for use with the present disclosure; 
       FIG. 2  is a block diagram illustrating a control system for use with the present disclosure; and 
       FIG. 3  is a block diagram illustrating an exemplary method for operating an implement for a machine. 
   

   DETAILED DESCRIPTION 
   Referring to the drawings, a method and apparatus  100  for operating an implement  149  of a machine  102  is shown. 
   For example, as exemplified in  FIG. 1 , the machine  102  is depicted as a track-type tractor. The machine  102  has a body  105  having left and right tracks  104 . The machine also has an implement  149 , shown as a winch  150  having a line  151 , and a dozer blade  152  mounted on the body  105 . The machine  102  is suitable for use in a number of earth working operations, such as mining, construction, and the like. However, other types of machines could also be used with the present disclosure, such as, but not limited to, skid-steer loaders, tracked loaders, excavators, pipelayers, forestry machines, agricultural machines, and off-highway vehicles. 
   An operator station or cab  106  is positioned on the body  105 . The operator station  106  may include a rollover protective structure (ROPS) and/or a falling object protective structure (FOPS) enclosing an operator seat. A pair of posts and an overhead guard may frame an optional door (not shown). The operator station  106  has a first operator input device  108 , shown as a joystick, although other types of input devices may also be used. For example, control levers, buttons, switches, or any other input device known in the art may also be used. The first operator input device  108  is operable to control the implement  149 . 
   A second operator input device  109  is also operable to control the implement  149 . The second operator input device  109  is shown as a first and a second switch  109   a ,  109   b , respectively, although other configurations may also be used. The first switch  109   a  may be operable to retract or reel-in the line  151  of the winch  150 , while the second switch  109   b  may be operable to allow the line  151  to extend by free-spooling the winch  150 . The second operator input device  109  is positioned external to the operator station  106 . For example, the second operator input device  109  may be positioned behind or on an access panel or service door (not shown) on the body  105  of the machine  102 , although the second operator input device  109  may be positioned elsewhere on the machine  102  as well. Alternately, the second operator input device  109  may be a remote control-based unit physically separate from the machine  102 . 
   A control system for the machine  102  is shown in  FIG. 2 . In this example, an engine  110  provides power to an auxiliary implement pump  120 , which ultimately powers the implement  149 . A controller  160  receives signals from the first and second operator inputs  108 ,  109  and controls the implement  149 . The engine  110  also powers a pump (not shown) that supplies a source of pressure  148 . The engine  110  may be any power source such as, for example, a diesel engine, a gasoline engine, a gaseous fuel driven engine, or any other engine known in the art. It is contemplated that the engine  110  may alternately include another source of power such as a fuel cell, a power storage device, an electric or hydraulic motor, and/or another source of power known in the art. The engine  110  may include an engine speed sensor (not shown) that is adapted to sense the output speed of the engine  110  and direct an engine speed signal representative of the rotational speed of the engine  110  to the controller  160  over a communication line (not shown). 
   The pump  120  supplies pressurized hydraulic fluid to a winch motor  130  through a first and second hydraulic conduit  121 ,  122 . The pump  120  may be configured to produce a variable output of pressurized fluid and may include a swash plate pump and/or any type of variable displacement pump. A bidirectional pump actuator or solenoid  123  adjusts the swash plate angle of the pump  120 , upstroking or downstroking the pump to increase or decrease the pressure supplied to the motor  130 . A shuttle valve  124  is coupled to the first and second hydraulic conduits  121 ,  122 , and allows a pressure sensor  125  to read the greater of the pressures in the hydraulic conduits  121  and  122 . 
   The winch motor  130 , powered by the pump  120 , supplies torque to the implement  149 . The implement  149  includes a brake  134  rotationally coupled to the motor  130 , a free spool  140  rotationally coupled to the brake, and the winch  150  rotationally coupled to the free spool. The brake  134  may selectively slow down or stop the rotation of the output shaft (not shown) to the winch  150 . The free spool  140  serves as a clutch by which a driving connection between two rotatable members operatively couple the motor to the winch. The two halves of the free spool  140  may be selectively engaged or disengaged from each other by a free spool piston  142 . A free spool valve  144  controls the operation of the free spool piston  142 . The free spool valve  144  is a two-position solenoid valve that is spring biased to a first position. In the first position of the valve  144 , the flow through the valve  144  from the source of pressure  148  is blocked, which results in the two halves of the free spool  140  being operatively engaged and allowing torque from the motor  130  to be transmitted to the winch  150 . The valve  144  is movable to a second position in response to receipt of an electrical signal from the controller  160 . In the second position, the valve  144  allows pressure from the source of pressure  148  to move the free spool piston  142 , disengaging the two halves of the free spool  140  from each other and decoupling the winch  150  from the motor  130 . 
   The controller  160  may receive and deliver signals via one or more communication lines. For example, the controller  160  receives implement commands from the first operator interface  108  over a first communication line  161 . Similarly, the controller  160  receives implement commands from the second operator interface  109  over a second communication line  162 . The controller  160  senses the pressure supplied by the pump  120  in the hydraulic conduit  121 ,  122  having the higher pressure from pressure sensor  125 . The controller  160  controls the pump solenoid  123  via a fourth communication line  164 . In addition, the controller controls the free spool valve  144  via a fifth communication line  165 . It is contemplated that the received and delivered signals may be any known signal format, such as, for example, a current or a voltage level. The controller  160  may be positioned in the body  105  of the machine  102  and may be an electronic control module and may also include one or more microprocessors, a memory, a data storage device, a communications hub, and/or other components known in the art. It is contemplated that the controller  160  may be further configured to receive additional inputs (not shown) indicative of various operating parameters of the machine  102  and or additional components, such as, for example, temperature sensors, positions sensors, and/or any other parameter known in the art. It is also contemplated that the controller  160  may be preprogrammed with parameters and/or constants indicative of and/or relating to the machine  102 . 
   INDUSTRIAL APPLICABILITY 
     FIG. 3  is a flow diagram illustrating a method for operating the implement  149  of the machine  102  and is discussed below. 
   In a first control block  202 , the controller  160  receives an implement command. For example, an operator may engage the first operator input device  108  while in the operator station  106 , or may engage the second operator input device  109  while outside of the operator station  106 . In a second decision block  204 , the controller  160  determines whether the implement command came from the first operator input  108 . The controller  160  may use the status of communication lines  161 ,  162 , a seat position sensor (not shown), a timer, or other techniques known in the art to distinguish between commands between the first and the second operator input devices  108 ,  109 . Alternately, if conflicting or concurrent commands are sent by both the first and second operator input devices  108 ,  109 , the controller  160  may limit the implement to the lesser of the commands from the first and the second operator input devices  108 ,  109 . 
   If the controller  160  determines that the first operator input  108  sent the implement command, a third control block  206  sets the controller  160  to have the first operator input  108  control the implement  149 . In a fourth control block  208 , the controller operates the implement  149  over its full motor torque range, permitting the winch  150  or implement  149  to operate up to its maximum power. The controller  160  may apply a scaling factor, a function, a look-up table or map that is based on various machine parameters, or any other technique known in the art to the implement command. The controller  160  controls the winch  150  by supplying an electrical signal, such as a current, over the fourth communication line  164  to the pump solenoid  123 . The pump solenoid  123  adjusts the swash plate of the pump  120 , increasing or decreasing the pressure supplied to the motor  130 . The pump  120  may be bidirectional, capable of supplying pressurized hydraulic fluid over either hydraulic conduit  121  or  122  to the motor  130 . In a reel-in direction, pressurized fluid is supplied over hydraulic conduit  121  to the motor  130 , and returning to the pump over hydraulic conduit  122 . In the reel-in mode, the winch  150  will reel-in the line  151 , pulling a load  153  towards the winch  150 . In contrast, if hydraulic fluid is first supplied over hydraulic conduit  122 , the motor  130  will reverse direction, causing the winch  150  to reel-out the line  151 . 
   If the controller  160  determines that the second operator input  109  sent the implement command, a fifth control block  210  sets the controller to have the second operator input  109  control the implement  149 . A sixth control block  212  has the controller  160  operate the implement  149  over a reduced range. In one exemplary embodiment, this reduced range may be approximately one percent of the full range of motor torque or line pull available to the winch  150 , although the limit may be changed depending on the application, machine, and model. In addition, the controller  160  may also correct for the changing radius off of the drum (not shown) of the winch  150  with varying torques available depending on the diameter of the line  151 , the number of coils of the line  151 , etc. The implement  149  may be operated over a reduced range by controlling the pump  120 . A signal may be applied over the communication line  164  that limits the actuation of the pump solenoid  123 , which in turn limits the angle of the swash plate. This restricts the pressure supplied to the motor  130 , and limits the torque available to the winch  150 . 
   A seventh control block  214  senses the pump-motor loop pressure. As described above, the pressure sensor  125  reads the higher pressure in the first hydraulic conduit  121  and the second hydraulic conduit  122  through the shuttle valve  124 . The pressure sensor  125  communicates that pressure to the controller  160  via the third communication line  163 . 
   An eighth control block  216  determines whether the sensed loop pressure exceeds a threshold value. If the pressure in the loop exceeds the threshold value, the controller  160  reduces the loop pressure in a ninth control block  218 . The controller  160  sends a signal over the fourth communication line  164  to the pump solenoid  123  to downstroke the swash plate of the pump  120 , ultimately reducing the torque supplied by the motor  130  to the winch  150 . The loop pressure would again be sensed as in the seventh control block  214 . If the pressure in the loop is below the threshold value, the algorithm would end and wait for another implement command. 
   As an example of an application of the present disclosure, an operator may operate the winch  150  of the machine  102  at a desired line pull. If the operator uses the first operator input device  108  located within the operator station  106 , the controller  160  allows the implement  149  to be operated over its full range, with no reduction in capacity. 
   However, if the controller  160  detects that the first switch  109   a  of the second operator input device  109  is used, the controller  160  senses the pressure supplied by the pump  120 . The controller  160  then limits the available line pull to a reduced range. This reduction may allow an operator to pull the line  151  taught without having to repeatedly enter and exit the operator station  106 . 
   If the second switch  109   b  of the second operator input device  109  is used, the controller  160  sends a signal over the fifth communication line to the free spool valve  144 , shifting the valve  144  to the second position. This second position allows pressurized fluid to move the free spool piston  142  and disengage the two rotatable members of the free spool  140  from each other, rotatably disengaging the winch  150  from the motor  130 . 
   While the disclosure has been described with reference to details of the illustrated embodiments, these details are not intended to limit the scope of the disclosure as defined in the appended claims. For example, other hydraulic control systems known in the art may be used to control the winch  150 . Other aspects, objects, and features of the present disclosure can be obtained from a study of the drawings, the disclosure, and the appended claims.