US Patent 7819207 Mobile land drilling rig and method of installation

A mobile oil, gas and geothermal well drilling rig provides for the rapid placement, assembly, disassembly, and repositioning of various rig components of the drilling rig. The drilling rig includes a support base and working floor which is trailerable and which can be rapidly erected to a working height at the well site. A drawworks trailer transports both the drawworks and the rig derrick. Hydraulic cylinders on the drawworks trailer are used to move the derrick from a horizontal, transport position to a vertical, working position while the weight of the derrick is off-loaded from the drawworks trailer to the base support structure.