Attachment frame with pivoting loader arm
An articulating work vehicle with a radially-pivoting lift arm, attached to a radially-pivoting base. The vehicle has a wheeled back section, on which an operator may stand, and a front, tool-carrying section, connected to the back section by an articulation joint. The front section has a system of actuators. These actuators cause a base tower to pivot relative to a frame, and a loader arm to pivot relative to the base tower. A tool, carried by the loader arm, may be self-levelling, and a bell crank allows the loader arm actuator's reaction point to float relative to the base tower.
1 . A lift arm assembly comprising:
a frame;
a base, pivotally attached to the frame about a substantially horizontal axis;
a first actuator directly attached at a first end to the base and at a second end to the frame;
a loader arm pivotally attached to the base about a substantially horizontal axis;
a second actuator attached at a first end to the loader arm, configured to pivot the loader arm relative to the base; and
a bell crank attached at a center position to the base, and at a distal position to the second actuator at a second end of the second actuator.
2 . The lift arm assembly of claim 1 further comprising a linkage disposed between the bell crank and the frame.
3 . The lift arm assembly of claim 1 further comprising:
a tool disposed on the loader arm; and
a third actuator attached at a first end to the loader arm and at a second end to the tool.
4 . The lift arm assembly of claim 3 further comprising:
a tilt member, attached at a first end to the bell crank at the distal position; and
a leveling mechanism, pivotally attached to the loader arm and having a first end and a second end; wherein:
the first end is attached to the tilt member; and
the second end is attached to the third actuator.
5 . The lift arm assembly of claim 3 in which the tool comprises a bucket.
6 . An articulated vehicle, comprising:
a main frame comprising a first ground engaging member;
an articulation joint disposed on the main frame; and
the lift arm assembly of claim 1 , pivotally attached to the main frame through the articulation joint wherein the frame of the lift arm assembly comprises a second ground engaging member.
7 . The articulated vehicle of claim 6 in which the main frame is configured for a standing operator.
8 . A work vehicle, comprising:
a mainframe, configured for standing operation and having at least one ground-engaging wheel;
an articulation joint attached to the mainframe;
a front assembly pivotally attached to the mainframe by the articulation joint and comprising:
a frame having a plurality of ground-contacting drive members;
a base, pivotally attached to the frame about a first axis, wherein the first axis is substantially horizontal; and
a loader arm, pivotally attached to the base about a second axis, wherein the second axis is substantially horizontal; and
a bell crank having a first end, a second end, and a center attachment point, and wherein:
the bell crank is attached to the base at the center attachment point; and
the bell crank is attached to the second actuator at the first end.
9 . The work vehicle of claim 8 further comprising:
a first actuator disposed between the frame and the base and directly attached to the frame and to the base; and
a second actuator configured to pivot the loader arm about the second axis.
10 . The work vehicle of claim 9 in which the second actuator is disposed between the base and the loader arm.
11 . The work vehicle of claim 9 in which the second axis is disposed closer to the mainframe than the first axis.
12 . The work vehicle of claim 8 further comprising a linkage, in which the linkage is disposed between the frame and the second end of the bell crank.
13 . The work vehicle of claim 12 in which the first axis is positioned further from the articulation joint than a connection point between the linkage and the frame.
14 . An articulated work vehicle comprising:
a main frame;
a first frame pivotally connected to the main frame about a substantially vertical axis;
a base section pivotally connected to the first frame about a first substantially horizontal axis;
a loader arm pivotally connected to the base section about a second substantially horizontal axis;
a bucket pivotally connected to the loader arm about a third substantially horizontal axis;
a first actuator directly attached to the first frame and configured to rotate the base section about the first substantially horizontal axis;
a second actuator attached to the base section and configured to rotate the loader arm about the second substantially horizontal axis;
a bell crank, having a first connection point, a second connection point, and a third connection point, wherein the second connection point is disposed between the first connection point and the third connection point;
wherein:
the second connection point is directly attached to the base section; and
the third connection point is coaxial with an end of the second actuator; and
a third actuator configured to rotate the bucket about the third substantially horizontal axis.
15 . The articulated work vehicle of claim 14 , further comprising:
a linkage, attached at a first end to the frame about a fourth substantially horizontal axis, wherein the first connection point of the bell crank is attached to the linkage.
16 . The articulated work vehicle of claim 15 , further comprising:
a tilt mechanism having a first connection point, a second connection point, and a third connection point, wherein the second connection point is disposed between the first connection point and the third connection point, and wherein the tilt mechanism is pivotally attached to the loader arm about the second connection point of the tilt mechanism; and
a tilt linkage directly connected to the third connection point of the bell crank and the third connection point of the tilt mechanism;
wherein the third actuator is connected to the first connection point of the tilt mechanism.
17 . The articulated work vehicle of claim 14 , in which the first actuator and the second actuator are defined by an extended condition and a retracted condition, and wherein:
with both the first actuator and the second actuator in the extended condition, the third substantially horizontal axis is above and forward of both the first substantially horizontal axis and the second substantially horizontal axis; and
with both the first actuator and the second actuator in the retracted condition, the third substantially horizontal axis is below and forward of both the first substantially horizontal axis and the second substantially horizontal axis, and the second substantially horizontal axis is above and behind the first substantially horizontal axis.