Expandable mechanical structure for mobile living units

A recreational vehicle, comprising:

• a main body;
• and
• a rear expansion structure operable to extend from a rear of the main body, the rear expansion structure increasing the interior living area within the mobile living unit, wherein:
• side walls of the rear expansion structure fold to store perpendicular to a direction of travel of the mobile living unit;
• and
• a floor of the rear expansion structure is stored, in a collapsed state of the rear expansion structure, in an upright position generally orthogonal to a use position when the rear expansion structure is in an expanded state.

A recreational vehicle comprising:

• a main body;
• and
• a rear expansion structure operable to extend from a rear of the main body, the rear expansion structure increasing the interior living area within the mobile living unit, wherein the rear expansion structure includes:
• a roof slidable along a fixed rail system disposed in the main body;
• an I-beam extend mechanism operable to extend and retract an I-beam that supports and moves a frame of the rear expansion structure;
• and
• a motor operable to drive the I-beam, wherein
• side walls of the rear expansion structure fold to store perpendicular to a direction of travel of the mobile living unit.