Patent ID: 8646240

Claim:
An apparatus for forming a mast assembly upon a floor of a drilling rig comprising: a support structure having a back surface and an opening; a first carriage assembly affixed to one side of said support structure, said first carriage assembly having a first carriage with a drive cylinder connected thereto so as to move said first carriage between a first lower position and a first upper position; and a second carriage assembly affixed to an opposite side of said support structure, said second carriage assembly having a second carriage with a drive cylinder connected thereto so as to move said second carriage between a second lower position and a second upper position, said first and second carriage assemblies suitable for a connection to a section of the mast assembly, each of said first and second carriage assembly comprising: an elongated beam assembly extended vertically so as to have an upper end positioned above said support structure and a lower end positioned in spaced relation above the floor, said elongated beam assembly comprising: a first I-beam having a channel formed longitudinally therein; and a second I-beam having a channel formed longitudinally therein, said first and second I-beams being affixed to said support structure such that the respective channels thereof face each other.