Roller for internal pipe welder

1. A pipeline unit for conducting a construction or inspection operation within a pipeline comprising:

a main frame;

a first low friction member for engaging the pipe interior and supporting a weight of the pipeline unit on an interior pipeline surface as the pipeline unit travels longitudinally within the pipeline;

a second low friction member for selectively engaging the pipe interior supporting a weight of the pipeline unit as the pipeline unit is rotated about the longitudinal axis of the pipeline;

a extension member including a first member connected to the main frame and a second member connected to the second low friction member;

a forcible extension mechanism;

wherein the forcible extension mechanism forcibly extends the first member relative to the second member to bring the wheel frame into contact with the pipeline interior and thereby raise the main frame and the pipeline unit off the pipeline interior to bear a portion of the weight of the pipeline unit; and

wherein during a rotational positioning, the pipeline unit rotates about a longitudinal axis of the pipeline.

2. The pipeline unit of claim 1 , wherein the first and second low friction members are wheels.

3. The pipeline unit of claim 1 , wherein the extension member includes a hydraulic or pneumatic piston and a cylinder.

4. The pipeline unit of claim 1 , wherein the first and second low friction members include a wheel and the wheel includes a wheel frame, the wheel frame includes two frame plates positioned on either side longitudinally of the wheel.

5. The pipeline unit of claim 4 , wherein a wheel is a plurality of wheels supported by the two frame plates and the plurality of wheels form an arcuate positioning to conform with a pipeline interior.

6. The pipeline unit of claim 1 , wherein the pipeline unit includes pipeline welding or pipeline inspection equipment.

7. The pipeline unit of claim 2 , wherein a wheel is a plurality of wheels.

8. The pipeline unit of claim 2 , wherein the wheel includes a rotational axis, the axis being generally parallel to a longitudinal center line of the unit.

9. In combination, a pipeline unit and a roller system for supporting the rotational repositioning of the pipeline unit within a pipeline against the weight of the pipeline unit, the pipeline unit including a main frame to which its components are secured, the combination comprising:

a pipeline unit, the pipeline unit including a clamp for engaging an interior surface of the pipeline;

a roller system including: a first longitudinal wheel for rollingly supporting longitudinal travel of the pipeline unit within the pipeline and a second rotational wheel including a rotational axis, the axis being generally parallel to a longitudinal center line of the unit; a wheel frame supporting the second rotational wheel and allowing the wheel to rotate about the axis;

an extension member including a first member connected to the main frame and a second member connected to the wheel frame;

a forcible extension mechanism;

wherein the forcible extension mechanism forcibly extends the first member relative to the second member to bring the wheel frame into contact with the pipeline interior and thereby raise the main frame and the pipeline unit off the pipeline interior to bear a portion of the weight of the pipeline unit.

10. The combination of claim 9 , wherein the extension member includes a piston and a cylinder.

11. The combination of claim 10 , wherein the wheel frame includes two frame plates positioned on either side longitudinally of the wheel.

12. The combination of claim 11 , wherein a wheel is a plurality of wheels supported by the two frame plates.

13. The combination of claim 12 , wherein the plurality of wheels forms an arcuate positioning to conform with a pipeline interior.

14. The combination of claim 12 , wherein a wheel is a plurality of wheels.

15. The combination of claim 10 , wherein the forcible extension mechanism is hydraulically or pneumatically driven.

16. The combination of claim 9 , further including a fluid supply and a fluid controller for selectively delivering fluid from the fluid supply to the extension member.

17. The pipeline unit of claim 2 , wherein the forcible extension mechanism is screw driven.

18. The combination of claim 9 , wherein the pipeline unit is one of an inspection unit, a welding unit, and a welding and inspection unit.

19. A method of rotationally repositioning a pipeline unit comprising the steps of:

providing a roller system for supporting the rotational repositioning of a pipeline unit against the weight of the pipeline unit, the pipeline unit including a main frame to which its components are secured;

providing a wheel including a rotational axis, the axis being generally parallel to a longitudinal center line of the unit;

providing a wheel frame supporting the wheel and allowing the wheel to rotate about the axis;

providing a extension member including a first member connected to the main frame and a second member connected to the wheel frame;

selectively extending the first member relative to the second member to cause the pipeline unit to be raised off the pipeline interior surface;

providing an elongate member that extends radially from the pipeline unit;

applying a rotational force to a lever until the pipeline unit rotates about the longitudinal centerline.

20. The method of claim 19 , further providing the step of providing an opening in the pipeline unit, and the step of securing a first end of the elongate member in the opening.