Terrain-adaptable support structure

A support structure for a mobile construction rig capable of adapting to uneven terrain comprising four support bearing members arranged at least approximately in a quadrilateral formation, said bearing members being arranged with bearing points which lie in a common reference plane when said structure is on flat terrain, said structure being configured to permit movement of said bearing members in a vertical direction relative to said reference plane and to couple said bearing members with each other in such a manner that when a first of said four bearing members is moved vertically relative to said reference plane, a second of said bearing members located diagonally opposite said first bearing member is deflected relative to said reference plane in the same direction and by approximately the same distance as said first bearing member, with the third and fourth bearing members of said four bearing members being both deflected relative to said reference plane in a direction opposite to the direction in which said first and second bearing members are deflected and by approximately the same distance.