Transport mode conversion

1. A construction machine, comprising:

a machine frame;

first, second, third, and fourth swing legs pivotally connected to the machine frame;

first, second, third, and fourth ground engaging units steerably connected to the first, second, third, and fourth swing legs, respectively, the ground engaging units including drive motors configured such that the ground engaging units are driven across a ground surface by the drive motors;

first, second, third, and fourth steering sensors configured to detect steering angles of the first, second, third, and fourth ground engaging units relative to the first, second, third, and fourth swing legs, respectively;

first, second, third, and fourth pivot sensors configured to detect pivot angles of the first, second, third, and fourth swing legs, respectively, relative to the machine frame;

first, second, third, and fourth locks configured to selectively lock and unlock the first, second, third, and fourth swing legs, respectively, in pivotal position relative to the machine frame; and

a controller including a transport re-orientation mode configured to rotate the machine frame substantially in place on the ground through a re-orientation angle, and as the machine frame is rotating to pivot the swing legs from an operating orientation to a transport orientation relative to the machine frame.

2. The machine of claim 1 , wherein:

the transport re-orientation mode is configured to pivot each of the swing legs one at a time in sequence.

3. The machine of claim 1 , wherein:

the transport re-orientation mode is configured to pivot the swing legs two at a time in pairs, one pair being the left front and right rear swing legs, and another pair being the right front and left rear swing legs.

4. The machine of claim 1 , wherein:

the transport re-orientation mode is configured to pivot all four swing legs at the same time.

5. The machine of claim 1 , wherein the re-orientation angle is in a range of plus or minus 30° about an odd multiple of 90°.

6. The machine of claim 1 , wherein the re-orientation angle is in a range of plus or minus 10° about an odd multiple of 90°.

7. The machine of claim 1 , wherein the re-orientation angle is substantially an odd multiple of 90°.

8. The machine of claim 1 , wherein the transport re-orientation mode is configured such that the machine frame is rotated in only one rotational direction as the machine frame is rotated through the re-orientation angle.

9. The machine of claim 1 , wherein the transport re-orientation mode is configured such that the machine frame is rotated first in one rotational direction and then in an opposite rotational direction as the machine frame is rotated through the re-orientation angle.

10. The machine of claim 1 , wherein:

the transport re-orientation mode is configured to, prior to pivoting the swing legs, steer each of the ground engaging units such that a drive axis of each of the ground engaging units intersects at substantially a common point defining a center of rotation of the frame.

11. The machine of claim 10 , wherein:

the center of rotation lies substantially on a center line of the frame mid-way between left and right sides of the frame.

12. The machine of claim 10 , wherein:

the machine frame includes a front and a rear; and

the center of rotation lies substantially on a lateral center line of the frame, the lateral centerline being substantially mid-way between front and rear of the machine frame.

13. The machine of claim 10 , wherein:

the machine frame includes a front and a rear; and

the center of rotation lies substantially offset from a lateral centerline of the frame, the lateral centerline being substantially mid-way between front and rear of the machine frame.

14. The machine of claim 1 , wherein:

the transport re-orientation mode is configured to pivot the swing legs at least in part by controlling relative speeds of the ground engaging units relative to each other.

15. The machine of claim 1 , wherein:

the transport re-orientation mode is configured to pivot the swing legs at least in part by controlling the steering angles of the ground engaging units to steer the ground engaging units at different steering angles relative to each other.

16. The machine of claim 1 , wherein:

the transport re-orientation mode is configured to pivot the swing legs at least in part by controlling the locks to selectively unlock each swing leg to allow the swing leg to pivot.

17. The machine of claim 1 , wherein:

the locks each include a hydraulic control system connected between the machine frame and the respective swing leg, and configured to change in length as the respective swing leg pivots relative to the machine frame, the hydraulic control system having a hydraulically blocked position preventing pivoting of the respective swing leg and a hydraulically un-blocked position permitting pivoting of the respective swing leg.

18. The machine of claim 17 , wherein:

the transport re-orientation mode is configured such that the hydraulic control system associated with each swing leg to be pivoted is moved to the un-blocked position.

19. The machine of claim 17 , wherein the each hydraulic control system includes:

a hydraulic ram having a piston and a cylinder, the piston dividing the cylinder into first and second ends;

a three way valve having an extension position, a retraction position, and a blocked position;

a first line and a second line connecting the three way valve to the first and second ends of the cylinder; and

wherein in the hydraulically blocked position of the hydraulic control system, the three way valve is in its blocked position.

20. The machine of claim 19 , wherein:

the hydraulic control system further includes first and second bypass valves connected to the first and second lines, respectively, each bypass valve including a blocked position and a bypass position, the bypass position communicating the respective line to a fluid reservoir;

in the hydraulically blocked position of the hydraulic control system, the first and second bypass valves are in their respective blocked positions; and

in a first hydraulically un-blocked position of the first hydraulic control system, the three way valve is in its blocked position and the first and second bypass valves are in their bypass positions; and

in a second hydraulically un-blocked position of the hydraulic control system, the first and second bypass valves are in their blocked positions and the three way valve is in either its extension or retraction position, and the controller is configured such that the first hydraulic ram actively facilitates the pivoting of the respective swing leg.

21. The machine of claim 19 , wherein:

in the hydraulically un-blocked position of the hydraulic control system, the three way valve is in either its extension or retraction position, and the controller is configured such that the hydraulic ram actively facilitates the pivoting of the respective swing leg.

22. The machine of claim 21 , wherein:

the controller is further configured such that the controller determines a degree of active facilitation of the pivoting in accordance with an algorithm.

23. The machine of claim 21 , wherein:

the hydraulic control system further includes a supply line and a pressure control valve located in the supply line; and

the controller is further configured such that the active facilitation of the pivoting of the respective swing leg by the hydraulic ram is limited to providing a hydraulic pressure to the hydraulic ram controlled by the pressure control valve.

24. The machine of claim 17 , wherein hydraulic control system includes:

a hydraulic ram having a piston and a cylinder, the piston dividing the cylinder into first and second ends;

first and second hydraulic lines connecting a fluid reservoir to the first and second ends of the cylinder, respectively; and

first and second bypass valves connected to the first and second hydraulic lines, respectively, each bypass valve including a blocked position and a bypass position, the bypass position communicating the respective end of the hydraulic ram to the fluid reservoir; and

wherein in the hydraulically blocked position of the hydraulic control system the first and second bypass valves are in the blocked positions; and

wherein in the hydraulically un-blocked position of the hydraulic control system the first and second bypass valves are in their bypass positions.

25. The machine of claim 1 , wherein the machine is a slipform paving machine.

26. The machine of claim 1 , wherein the ground engaging units comprise crawler tracks.