Automatically adjusting swing legs for mounting and aligning and reorienting crawlers
A swing leg assembly for a paving machine having a main frame and crawler tracks. The main frame can include a center module and laterally movable bolsters. The swing leg for each crawler track supports an upright jacking column. Worm gear drive permits rotational movements of the crawler track relative the jacking column. A pivot hinge is interposed between each swing leg and frame to enable pivotal movements of the swing leg in relationship to the paving machine. The holder permits pivotal motions of the swing leg in its length-adjustable configuration and prevents substantially any motion of the swing leg in its fixed-length configuration. A feedback loop cooperates with transducers to keep the crawler tracks in position. The paving machine can be configured as a four-leg design or a three-leg design utilizing a telescopic or sliding mechanism for one or more crawler track with jacking column.
1 . A swing leg assembly configured to be coupled to a paving machine configured to move in a paving direction for spreading, leveling, and finishing concrete into a form having a generally upwardly exposed, finished concrete surface and terminating in lateral concrete sides, the swing leg assembly comprising:
a swing leg configured to be pivotally mounted to the paving machine by a pivot hinge and configured to pivot about a first axis of the pivot hinge to a first angular orientation relative to the paving machine;
a jacking column coupled to the swing leg, the jacking column comprising a telescoping inner tube within an outer tube extending along an upright axis;
a vertically oriented hydraulic actuator located along the upright axis, the hydraulic actuator comprising a cylinder and a piston operable within the outer and inner tubes; and
spaced apart axial bearings coupled to the outer tube and/or the inner tube;
a crawler track rotatably coupled to the jacking column, wherein the crawler track is configured to rotate about a second axis to a second angular orientation relative to the jacking column;
a slew drive coupled to the jacking column and the crawler track, wherein the slew drive is configured to cause rotation of the crawler track relative to the jacking column;
a first sensor configured to emit a first signal corresponding to the first angular orientation;
a second sensor configured to emit a second signal corresponding to the second angular orientation;
a telescopic bolster or sliding mechanism associated with each crawler track, wherein each telescopic bolster or sliding mechanism is hydraulically actuated to move the crawler track laterally, wherein a first lineal position transducer is disposed on the modular frame or sliding mechanism to measure a lineal position between the jacking column and the modular frame and further emit a first signal indicative of the measured lineal position to an onboard controller having a processor; and
wherein the processor is configured to:
receive the first signal from the first sensor, and the second signal from the second sensor;
determine a change of the first angular orientation based on the first signal;
in response to determining the change of the first angular orientation, determine a target second angular orientation based at least in part on the determined change of the first angular orientation and the second angular orientation based on the second signal; and
send a control signal to the slew drive in order to cause the second angular orientation of the crawler track to rotate to the target second angular orientation while the crawler track is under load during paving, walking or maneuvering around a job site.
2 . The swing leg assembly of claim 1 , wherein the axial spaced-apart bearings are configured to limit backlash between the inner and the outer tubes of the jacking column, while keeping the inner and outer tubes aligned and allowing the inner and outer tubes to slide against each other.
3 . The swing leg assembly of claim 2 , wherein rotational movement of the crawler track ranges between 180 degrees on either side of the upright axis.
4 . The swing leg assembly of claim 1 , wherein the slew gear drive is configured to steer and/or maintain the crawler track in a preset position under load.
5 . The swing leg assembly of claim 1 , wherein the slew gear drive is configured for precision movement between the jacking column and the crawler track while under load and without lifting the crawler track off the ground and to limit backlash to avoid adversely affecting steering accuracy of the crawler track.
6 . The swing leg assembly of claim 1 , wherein the swing leg is configured to relocate the jacking column with the crawler track while moving and under load.
7 . The swing leg assembly of claim 1 , wherein the processor of the controller is configured to:
receive the first and second signals;
determine a change of the first orientation based on the first signal;
in response to determining the change of the first orientation, determine a target second orientation based at least in part on the determined change of the first orientation and the second orientation based on the second signal; and
send a control signal to the slew drive in order to cause the second orientation of the crawler track to rotate to the target second orientation.
8 . The paving machine of claim 1 , wherein the slew drive is operably coupled to a motor configured to receive the power from a power supply, a ring gear driven by the slew drive and at least one bushing.
9 . The paving machine of claim 1 , wherein the processor is configured to operate according to a feedback loop in which the computer receives the angular position signal from first and/or second sensor and outputs operational commands in response.
10 . The paving machine of claim 9 , wherein the feedback loop is such that when the angular position of the swing leg changes, the output signal from the first and/or second sensor changes correspondingly.
11 . The paving machine of claim 1 , wherein the first sensor is located at the pivot hinge for the swing leg.
12 . The paving machine of claim 11 , wherein the second sensor is located between the jacking column and the crawler track.
13 . The paving machine of claim 1 , wherein the processor is further configured to:
compute angular offsets between first and second component positions based on first and second signals from the first and second sensors; and
determine coordinated actuator commands based on the angular offsets.
14 . The paving machine of claim 13 , wherein the processor configured to compute the angular offsets as a difference between an actual orientation and a desired orientation for each component and generates compensation commands to reduce the offsets over time.
15 . The paving machine of claim 1 , wherein the processor is configured with a closed loop feedback system that connects a hydraulic actuator for the swing leg, a rotary power drive for the crawler, and the onboard controller maintains the swing leg angle at a fixed, preset angle.
16 . The paving machine of claim 15 , wherein the processor is further configured such that if the swing leg migrates away from a preset angle, the hydraulic actuator is actuated to maintain the preset angle and at the same time the necessary adjustments to the crawler track orientation are made with the rotary power drive or steering cylinder.
17 . The paving machine of claim 1 , wherein the processor is configured with a closed loop feedback system that connects a hydraulic actuator for the swing leg, a rotary power drive for the crawler, and the onboard controller configured to allow the swing leg with crawler track to be repositioned under load while paving and maintaining the paving direction.
18 . A paving machine comprising to the swing leg assembly of claim 1 .
19 . The paving machine of claim 18 , wherein the paving machine includes four legs.
20 . The paving machine of claim 18 , wherein the paving machine is configured for transforming into a transport mode when the machine is stopped and further configured for a 90 degree steering mode from any swing leg angle where the machine can travel transversely and steer from the normal paving direction.
21 . The paving machine of claim 18 , wherein the paving machine includes three or more swing leg assemblies, wherein the paving machine and processor is configured to automatically reposition the three or more swing leg assemblies, including the jacking column and crawler track, along a tight radius curve while moving or paving.
22 . The paving machine of claim 21 , wherein the tight radius curves is at least 90 degrees and up to 180 degrees.
23 . The paving machine of claim 18 , wherein the slew drive between the crawler track and the jacking column allows the crawler track from any swing leg position to be turned 90° relative to a previous direction of travel while under load, thereby allowing lateral travel and steering of the paving machine.
24 . The paving machine of claim 18 , wherein the processor is configured to coordinate automatically or semi-automatically repositioning of the jacking column and/or crawler track positions on the fly to avoid obstacles or severe grade deviations in a path of the crawler tracks during paving.
25 . A swing leg assembly configured to be coupled to a paving machine configured to move in a paving direction for spreading, leveling, and finishing concrete into a form having a generally upwardly exposed, finished concrete surface and terminating in lateral concrete sides, the swing leg assembly comprising:
a frame;
a plurality of jacking columns;
a plurality of swing legs, each swing leg coupled to a jacking column, wherein each swing leg is coupled to the modular frame via a hinged bracket and hydraulically actuated to pivot the respective swing leg about a vertical axis,
a first angular position transducer for each of the plurality of swing legs, wherein each first angular position transducer is disposed on the respective swing leg or the frame adjacent the swing leg to measure an angular position between the respective swing leg and the frame and configured to emit a first signal indicative of the measured angular position to an onboard controller, the controller having a processor configured to control operation of the paving machine;
a crawler track associated with each respective jacking column, each crawler track coupled to a yoke which is rotatably coupled to the respective jacking column, wherein each crawler track is configured to rotate about a second axis to a second angular orientation relative to the jacking column, wherein the crawler track is repositionable while under load during paving, walking or maneuvering around a job site;
wherein each jacking column of the plurality of jacking column comprises: a telescoping inner tube within an outer tube extending along an upright axis of the jacking column, a vertically oriented hydraulic actuator located along the upright axis, the hydraulic actuator comprising a cylinder and a piston operable within the outer and inner tubes, and spaced apart axial bearings coupled to the outer tube and/or the inner tube;
one or more additional crawler tracks, each having a jacking column associated with a telescopic bolster or sliding mechanism, wherein each telescopic bolster or sliding mechanism is hydraulically actuated to move each additional crawler track with jacking column laterally, wherein a first lineal position transducer is disposed on the modular frame or sliding mechanism to measure a lineal position between the additional jacking column and the modular frame and further emit a first signal indicative of the measured lineal position to the controller;
a slew gear drive secured at a lower end of the jacking column inner tube and to a top of the yoke to translate relative rotational movements between each respective jacking column and crawler track about the upright axis; and
a second angular position transducer on each crawler track configured to measure an angular position of the respective crawler track and the yoke relative to the jacking column and further emit a second signal indicative of the measured angular position to the controller.
26 . The swing leg assembly of claim 25 , wherein the axial spaced-apart bearings are configured to limit backlash between the inner and the outer tubes of the jacking column, while keeping the tubes aligned and allowing the inner and outer tube to slide against each other.
27 . The swing leg assembly of claim 25 , wherein rotational movement of the crawler track ranges between 180 degrees on either side of the upright axis.
28 . The swing leg assembly of claim 25 , wherein the slew gear drive is configured to steer and/or maintain the crawler track in a preset position under load.
29 . The swing leg assembly of claim 25 , wherein the slew gear drive is configured for precision movement between the jacking column and the crawler track and to limit backlash to avoid adversely affecting steering accuracy of the crawler track.
30 . The swing leg assembly of claim 25 , wherein the swing leg is configured to relocate the jacking column with the crawler track while moving and under load.
31 . The swing leg assembly of claim 25 , wherein the processor is configured to:
receive the first and second signals;
determine a change of the first orientation based on the first signal;
in response to determining the change of the first orientation, determine a target second orientation based at least in part on the determined change of the first orientation and the second orientation based on the second signal; and
send a control signal to the slew drive in order to cause the second orientation of the crawler track to rotate to the target second orientation.