Tilt-up door

A tilt-up door system for a building having an opening comprising:

• first and second juxtaposed members each comprising a web and first and second spaced flanges forming a generally U-shaped channel and having upper and lower portions extending substantially vertically along opposite sides of the opening with the generally U-shaped channels facing each other and the opening;
• first and second curved cam surfaces connected at one end to and extending generally laterally from respective ones of the first and second juxtaposed members at the upper portion thereof;
• a door sized to span the opening having;
• a top, a bottom and at least two vertical side members, the at least two side members each having a horizontally extending pivot shaft tube positioned vertically between the top and bottom of the door;
• and
• first and second cam followers connected to the door extending laterally from an upper portion of the door in register with respective ones of the first and second cam surfaces;
• first and second carriages each including a horizontally extending pivot shaft journal and at least two wheels, each of the carriages being positioned in one of the U-shaped channels for vertical movement in the respective U-shaped channels;
• a pair of horizontally extending pivot shafts, each pivot shaft pivotally connecting a pivot shaft tube to a pivot shaft journal;
• and
• at least one actuator connected to the first and second carriages operable to move the first and second carriages in the U-shaped channels;
• whereby when the door is placed in alignment with the opening in a closed, lowered position, the first and second carriages are positioned for vertical movement in respective ones of the U-shaped channels and the first and second cam followers are in register with respective ones of the first and second cam surfaces, when the at least one actuator is operated to move the first and second carriages vertically in respective ones of the U-shaped channels the first and second cam followers move along respective ones of the first and second cam surfaces to tilt the door to a generally horizontal position as the door is moved vertically upward by the carriages.