rotary table and draw works are supported is on a separate framework supported on and attached to a structural frame or base for the drilling rig the floor structure is broken down into a plurality of parts for ease in transportation each of which have independent columns and cross bracing the central portion of the floor which supports the rotary table and which must support the full weight of the drill pipe has special heavy columns which are supported on a structural base in substantially the same position as the base connection of the mast when in a raised position therefore weight can be transferred from the rotary table to the crown block and vice versa and the weight is still applied to the base frame in substantially the same position application_number US 59363675 A description referring now to the drawings and in particular to fig1 there is shown by the numeral 10 a general view of the structural base of the drilling rig numeral 12 indicates generally the work table or the floor of the rig numeral 14 indicates generally the mast of the drilling rig and numeral 16 indicates generally the a frame the base 18 of the structural frame 10 rests on the ground surface 15 this frame as shown in fig3 is made up of four vertical box sections two on each side of the frame with a low central part 26 which provides a cross section roughly in the shape of a u this shape is a very important feature of the design it provides adequate longitudinal rigidity to the base and supports the mast at some distance above the ground it also makes provision for tilting the mast into a horizontal position wherein the mast.