and in turn the center section 22 rests upon the shelf accordingly the center section 22 is supported on the shelves of the driller and off driller side substructure sections 0053 fig8 is a top view of the connection shown in fig7 a set of pins 78 extends through the tube 74 and through the shelf 76 in order to secure the center section to the side sections while fig7 and 8 illustrate the connection between the center section and the off driller side subsection a similar arrangement is provided to connect the center section with the drillers side section 0054 fig9 illustrates an enlarged view of the pivotal connection between the base 30 of the drillers side section and the rear leg or legs 38 a stop 80 extending from the base 30 restricts the rear leg 38 from moving past the vertical position the rear legs 38 move about a hinge 82 between the upright position shown in fig9 and 11 and a lower position it will be observed that the pin does not carry any of the load of the substructure while in the upright use position 0055 fig1 shows an enlarged view of the pivotal connection between the base 30 of the drillers side subsection and the front.