Rear stepper assembly for a pipe handling vehicle

For use in a pipe transporting vehicle of the type which cradles a large pipe between supporting wheel sets at either end of the vehicle, a stepper assembly for stepping into and out of the pipe which comprises:

• a. a vertical stanchion;
• b. a support structure having a sleeve in receipt of the stanchion;
• c. vertical shock absorber and load transferring means between the support structure and the stanchion to vertically load couple the two together while permitting relative vertical movement between the two;
• d. slide bearing means between the stanchion and the support structure to transfer horizontal forces and moments from one of them to the other of them;
• e. a walking beam pivotally secured to the stanchion at the stanchion's lower end for pivotal movement about an axis transverse to the line of movement of the stepper assembly along a path, the walking beam extending in each fore-and-aft direction from the pivot to define fore-and-aft ends thereof spaced from the pivot;
• f. fore-and-aft trunnions on the fore-and-aft ends of the walking beams and extending along the fore-and-aft axis of the walking beams;
• g. fore-and-aft axle assemblies journaled on the trunnions for pivotal movement about the axis thereof, the axles extending transversely to the fore-and-aft axis;
• h. a wheel mounted on each end of each of the axle assemblies for rotation about axes transverse to the fore-and-aft direction and transport of the stepper assembly parallel to the fore-and-aft direction;
• and
• i. fore-and-aft power cylinders secured at one end to the stanchion and at the other end to the fore-and-aft ends of the walking beam such that actuation of individual of the cylinders will lift one end of the walking beam and enable the wheels thereat to step while the weight of the stepper assembly and its carried load are supported by the wheels at the other end of the walking beam.

In a pipe transporting vehicle of the type which cradles a large pipe between supporting wheels of supporting axle sets at either end of the vehicle, a stepper assembly for stepping into and out of pipe which comprises:

• a. a vertical stanchion;
• b. a weldment having a sleeve for receipt of the stanchion, a pair of arms extending forward of the sleeve, and means at the forward end of the arms for pivotally coupling about a vertical axis the weldment to a carriage of the transporting vehicle;
• c. vertical load transferring and shock absorber means between the sleeve and the stanchion for transferring vertical loads between the sleeve and the stanchion and for dissipating energy passing from them;
• d. a walking beam pivotally connected to the lower end of the stanchion about an axis transverse to the fore-and-aft direction of the vehicle such that the walking beam extends parallel to the fore-and-aft direction of the vehicle and presents fore-and-aft ends spaced from the pivot;
• e. fore-and-aft axle assemblies pivotally coupled to the walking beam at the fore-and-aft ends thereof, respectively, the pivotal coupling of each of the axle assemblies being about an axis extending in the fore-and-aft direction such that the axle assemblies are capable of tilting with respect to the vehicle;
• f. a wheel set for each of the axle assemblies, each wheel set having at least two wheels with the wheels of a set being rotatably mounted at either end of the axle assemblies;
• g. upper and lower, vertically spaced apart slide bearing arms between the sleeve and the stanchion to permit relative vertical movement of the sleeve with respect to the stanchion and to transfer horizontal forces and moments about all axes between the two;
• and
• h. forward and aft power cylinder means coupled between the stanchion and the fore-and-aft ends of the walking beam, respectively, each power cylinder being independently actuatable from the other to permit the lifting and lowering of the end of the walking beam to which it is attached while the wheels at the end of the walking beam attached to the other cylinder remain on the ground.