Patent Application
20190316324
The present disclosure relates to a work vehicle which includes a work implement.
In some embodiments, the disclosure provides a work vehicle comprising a frame, a prime mover connected to the frame, an operator cab connected to the frame, a work implement moveable with respect to the frame, and a control circuit that can control movement of the work implement. The control circuit includes a pump, an actuator in fluid communication with the pump, a control valve fluidly positioned between the pump and the actuator, and a proportional relief valve fluidly positioned between the pump and the actuator. The proportional relief valve can permit flow of fluid from the actuator in response to an impact at a predetermined force, and the predetermined force is adjustable by a user.
In some embodiments, the disclosure provides a control system that controls movement of a work implement of a work vehicle. The control system includes a pump, a first actuator in fluid communication with the pump, a first control valve fluidly positioned between the pump and the first actuator, a first proportional relief valve fluidly positioned between the pump and the first actuator, a second actuator in fluid communication with the pump, a second control valve fluidly positioned between the pump and the second actuator, and a second proportional relief valve fluidly positioned between the pump and the second actuator. The first proportional relief valve permits flow of fluid from the first actuator upon an impact at a first set force. The first set force is adjusted by a user. The second proportional relief valve permits egress of fluid from the second actuator upon an impact at a second set force. The second set force is adjusted by a user.
In some embodiments the disclosure provides a method of moving a work implement of a work vehicle in response to an impact force. The method includes setting a pressure at which a proportional relief valve is configured to open via an operator positioned in the work vehicle, and monitoring an actuator to detect movement thereof from a first position. Upon movement of the actuator from the first position, the method includes determining if an operator commanded the actuator to move. If an operator commanded the actuator to move, the method includes detecting a second position of the actuator. If an operator did not command the actuator to move, the method includes moving the actuator back to the first actuator position.
Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways.
The grader 10 includes a circle 46 disposed in front of the operator cab 26 and suspended below the front frame 18 by a lifter bracket 50 and a drawbar 54. A work implement, which is a blade 58 or moldboard in the illustrated embodiment, extends laterally across the circle 46. The grader 10 includes a blade positioning assembly 62 that allows the position and orientation of the blade 58 to be adjusted. In the illustrated embodiment, a left lift actuator 66 and a right lift actuator 68 extend between the lifter bracket 50 and the circle 46 to tilt, raise, and lower the circle 46 and the blade 58. A shift actuator 70 is provided to shift the blade 58 laterally relative to the front frame 18, and a pitch actuator 74 (
The prime mover 30 is coupled to the rear wheels 42 via a suitable transmission (not shown) to drive the rear wheels 42 (
The front frame 18 of the grader 10 defines a first or front longitudinal axis 90, and the rear frame 22 of the grader 10 defines a second or rear longitudinal axis 94. An articulation joint 98 pivotally couples the front frame 18 and the rear frame 22 and defines a vertical pivot or articulation axis 102 (
As shown in
The right lift actuator 68 includes a rod side that is fluidly coupled to a first conduit 150 and a piston side that is fluidly coupled to a second conduit 154. The first conduit 150 is fluidly coupled to a right control valve 158 which selectively directs flow into and out of the piston side of the right lift actuator 68. A pump (not shown) provides a flow of pressurized fluid into the right control valve 158. The second conduit 154 is fluidly coupled to both the right control valve 158 and a right proportional relief valve 162. When the pressure in the right lift actuator 68 is above a set threshold pressure, the right proportional relief valve 162 opens to permit fluid to flow from the piston side of the right lift actuator 68 into a reservoir 166. In the illustrated embodiment, the right proportional relief valve 162 is separate from the right control valve 158. In some embodiments, the right proportional relief valve 162 is incorporated into the right control valve 158.
At step 212, the control system 128 determines if the movement of the one or both of the left and right lift actuators 66 and 68 was commanded by the operator. If the control system 128 determines that the movement of one or both of the left and right lift actuators 66 and 68 was commanded by the operator at step 212, operation returns to step 200. If the control system 128 determines that the movement of one or both of the left and right lift actuators 66 and 68 was not commanded by the operator at step 212, operation moves to step 216.
At step 216, the control system 128 sends a command to the one or both of the left and right lift actuators 66 and 68 to return to the captured cylinder position of step 200. Operation then returns to step 204 at which the control system 128 monitors the position of the left and right lift actuators 66 and 68. In some embodiments, step 216 can include notifying the operator to move the one or both of the left and right lift actuators 66 and 68 to the captured cylinder position. In some embodiments, step 216 includes requesting authorization from the operator to return the one or both of the left and right lift actuators 66 and 68 to the captured cylinder position. In some embodiments, step 216 includes automatically returning the one or both of the left and right lift actuators 66 and 68 to the captured cylinder position.
During operation, if the blade 58 impacts a hard object, such as a frozen object, rocks, clay, etc., a pressure in the piston side of one or both of the lift actuators 66 and 68 can increase rapidly. In response to the rapid pressure increase, one or both of the proportional relief valves 142 and 162 can open to permit fluid to exit the piston side of the respective lift actuator 66 and 68 to thereby lower the pressure on the piston side of the respective lift actuator 66 and 68. The respective one or both of the lift actuators 66 and 68 are then permitted to raise the blade 58 above the hard object to inhibit the hard object from damaging the blade 58 or any other portion of the grader 10.
In some embodiments, the lift actuators 66 and 68 are coupled such that if one of the proportional relief valves 142 or 162 exceeds a pre-determined pressure, both of the proportional relief valves 142 and 162 open to raise the blade 58. In other embodiments, the lift actuators 66 and 68 operate independently such that when one of the proportional relief valves 142 or 162 exceeds a pre-determined pressure, only the respective proportional relief valve 142, 162 opens while the other proportional relief valve 142, 162 remains closed.
The operator can set and change the pre-determined pressure at which the proportional relief valves 142, 162 open. In some embodiments, the operator can set and change the pre-determined pressure with the user-manipulable control 126 in the operator cab 26. In some embodiments, the operator can set and change the pre-determined pressure with one or more controls that are remote from the grader 10.
Thus, the disclosure provides, among other things, a work vehicle having an adjustable pressure at which one or more relief valves open to raise a work implement and in which the operator can adjust the pressure from the cab and/or from a location remote from the cab.
Various features and advantages of the disclosure are set forth in the following claims.
