Loader with telescopic lift arm

1. A power machine comprising:

a frame;

a cab mounted on the frame;

a lift arm structure having a boom pivotally mounted to a front of the frame at a pivot connection position substantially forward of the cab, the lift arm structure having a telescoping arm coupled to the boom and configured to extend from and retract into the boom;

an implement interface coupled to a distal end of the telescoping arm of the lift arm structure and configured to mount an implement to the lift arm structure;

a first actuator coupled between the boom and the frame and configured to raise and lower the boom;

a second actuator coupled between the telescoping arm and the boom and configured to extend and retract the telescoping arm relative to the boom;

a control system including a controller configured to control the first and second actuators during a lift operation such that the first actuator raises the boom and such that the second actuator extends and retracts the telescoping arm to maintain a substantially vertical path of the implement interface or the implement attached to the implement interface throughout the lift operation; and

a first sensor configured to provide an output indicative of a position of the boom relative to a reference and a second sensor configured to provide an output indicative of a position of the telescoping arm relative to the boom, and wherein the control system is configured to control the first and second actuators during the lift operation as a function of the outputs of the first and second sensors.

2. The power machine of claim 1 , wherein the control system is configured to control the first and second actuators during the lift operation such that as the first actuator raises the boom from a lowered position to an intermediate position the second actuator retracts the telescoping arm to maintain the substantially vertical path of the implement interface or the implement attached to the implement interface.

3. The power machine of claim 2 , wherein the control system is configured to control the first and second actuators during the lift operation such that as the first actuator raises the boom upward from the intermediate position the second actuator extends the telescoping arm to maintain the substantially vertical path of the implement interface or the implement attached to the implement interface.

4. The power machine of claim 3 , and further comprising at least one operator input device coupled to the control system and wherein the control system is configured to control the first and second actuators during the lift operation, responsive to input from the at least one operator input device, to maintain the substantially vertical path of the implement interface or the implement attached to the implement interface.

5. The power machine of claim 1 , wherein the control system is configured to control the first and second actuators during the lift operation such that the implement interface or the implement attached to the implement interface follows a preset path including the substantially vertical path.

6. The power machine of claim 5 , wherein the preset path extends beyond the substantially vertical path.

7. The power machine of claim 5 , wherein the preset path includes a path portion which is not parallel to the substantially vertical path.

8. The power machine of claim 1 , wherein the control system is configured to control the second actuator to move the implement interface or the implement attached to the implement interface both vertically and horizontally from a loading position to a carry position without movement of the boom by the first actuator.

9. A power machine comprising:

a frame;

a lift arm structure having a first arm pivotally mounted to the frame and a second arm coupled to the first arm and configured to extend from and retract into the first arm;

an implement interface coupled to a distal end of the second arm of the lift arm structure and configured to mount an implement to the lift arm structure;

a first actuator coupled between the first arm and the frame and configured to raise and lower the first arm by pivoting the first arm relative to the frame;

a second actuator coupled to the second arm and the first arm and configured to extend and retract the second arm relative to the first arm to control a position of the implement interface or the implement attached to the implement interface relative to the first arm;

at least one operator input device configured to provide an operator input;

a control system including a controller configured to control the first and second actuators, responsive to the operator input, to implement a lift operation, wherein during the lift operation the first actuator raises the first arm and the second actuator extends and retracts the second arm relative to the first arm to maintain a substantially linear path of the implement interface or the implement attached to the implement interface, wherein the control system is further configured to control the second actuator to move the implement interface or the implement attached to the implement interface both vertically upward away from a support surface and horizontally toward the frame from a loading position to a carry position, above a front axle of the power machine, without movement of the first arm by the first actuator.

10. The power machine of claim 9 , wherein the substantially linear path is substantially orthogonal to a support surface on which the power machine is positioned.

11. The power machine of claim 9 , wherein the substantially liner path is a substantially vertical path.

12. The power machine of claim 11 , wherein the substantially vertical path is a first portion of a preset path which includes a second path portion that is not parallel to the substantially vertical path.

13. The power machine of claim 9 , and further comprising a first sensor configured to provide an output indicative of a position of the first arm relative to a reference and a second sensor configured to provide an output indicative of a position of the second arm relative to the first arm, and wherein the control system is configured to control the first and second actuators during the lift operation as a function of the outputs of the first and second sensors.

14. The power machine of claim 13 , wherein the control system is configured to control the first and second actuators during the lift operation such that as the first actuator raises the first arm from a lowered position to an intermediate position the second actuator retracts the second arm to maintain the substantially linear path of the implement interface or the implement attached to the implement interface.

15. The power machine of claim 14 , wherein the control system is configured to control the first and second actuators during the lift operation such that as the first actuator raises the first arm upward from the intermediate position the second actuator extends the second arm to maintain the substantially linear path of the implement interface or the implement attached to the implement interface.

16. A power machine comprising:

a frame;

a lift arm structure having a boom pivotally mounted to the frame and a telescoping arm coupled to the boom and configured to extend and retract relative to the boom;

an implement interface coupled to a distal end of the telescoping arm of the lift arm structure and configured to mount an implement to the lift arm structure;

a first actuator coupled between the boom and the frame and configured to raise and lower the boom;

a second actuator coupled between the telescoping arm and the boom and configured to extend and retract the telescoping arm relative to the boom;

a control system including a controller configured to control the second actuator to move the implement interface or the implement attached to the implement interface both vertically upward away from a support surface and horizontally toward the frame from a loading position to a carry position that is vertically further from the support surface than the loading position, wherein in the loading position the boom is in a lowered position and the telescoping arm is in an extended position, and wherein in the carry position the boom remains in the lowered position and the telescoping arm is in a retracted position.

17. The power machine of claim 16 , and further comprising a third actuator coupled between the telescoping arm and the implement interface and configured to control rotation of the implement interface relative to the telescoping arm, wherein the controller is further configured to rotate the implement interface or the implement attached to the implement interface relative to the telescoping arm when moving the implement interface or the implement attached to the implement interface from the loading position to the carry position.

18. The power machine of claim 16 , wherein when the implement interface is in the loading position a bottom of the implement interface is positioned less than 20 centimeters above the ground, and wherein when the implement interface is in the carry position, the bottom of the implement interface is positioned at least 20 centimeters above the ground.

19. The power machine of claim 16 , wherein when the implement interface is in the loading position a bottom of the implement interface is positioned below a front axle of the power machine, and wherein when the implement interface is in the carry position, the bottom of the implement interface is positioned above the front axle of the power machine.

20. A power machine comprising:

a frame;

a lift arm structure having a boom pivotally mounted to the frame and a telescoping arm coupled to the boom and configured to extend from and retract into the boom;

an implement interface coupled to a distal end of the telescoping arm of the lift arm structure and configured to mount an implement to the lift arm structure;

a first actuator coupled between the boom and the frame and configured to raise and lower the boom;

a second actuator coupled between the telescoping arm and the boom and configured to extend and retract the telescoping arm relative to the boom;

at least one operator input device configured to generate an auto-carry command in an auto-carry mode of operation;

a control system coupled to the at least one operator input device and including a controller configured to control the first and second actuators during a lift operation such that the first actuator raises the boom and such that the second actuator extends and retracts the telescoping arm to maintain a substantially vertical path of the implement interface or the implement attached to the implement interface throughout the lift operation, wherein in the auto-carry mode of operation the control system is configured to control the second actuator, responsive to the auto-carry command, to automatically move the implement interface or the implement attached to the implement interface both vertically upward away from a support surface and horizontally toward the frame from a loading position to a carry position without movement of the boom by the first actuator; and

a first sensor configured to provide an output indicative of a position of the boom relative to a reference and a second sensor configured to provide an output indicative of a position of the telescoping arm relative to the boom, and wherein the control system is configured to control the first and second actuators during the lift operation as a function of the outputs of the first and second sensors.

21. The power machine of claim 20 , and further comprising a cab mounted on the frame, wherein the boom of the lift arm structure is pivotally mounted to the frame forward of the cab.