How does a bifold door work?
If you're looking for doors for your closet or laundry area, you might want to consider bifold doors. Unlike sliding doors, bifold doors allow you to see the entire contents inside the closet all at once. They also have an advantage over pull-out or French doors because they take up half as much space.
Of course, bifold doors aren't just for closets. Many people use them to close off one room from another. Then there are the bifold doors used in agricultural buildings and aircraft hangars. They fold in a different way but are used because they put less stress on the building than the single swing-out door.
How the Household Bifold Door Works
Household bifold doors work by folding in half while they are being opened. There is a track installed at the top and the bottom of an opening. The door is hinged and attached to the outside wall and hinged in the centre to allow it to fold. There are pivot points that are placed into the top and bottom tracks that keep the doors running in the track and prevent them from opening up into the room. Some bifold doors don't use a bottom track. They use a floor bracket that keeps the door in place when it is shut. Most bifolds can be adjusted from the bottom or top pivot to make them run in the track correctly.
How the Agricultural or Aircraft Hangar Bifold Door Works
Commercial bifold doors open opposite the way that household doors do. As the door comes up like a garage door, it folds in half and is slightly angled to allow rain or snow to drain off the front of the door and not collect on top of it. Because these doors are so large, the fact that they fold in half instead of just pulling up all together takes much of the stress off the front of the building.
Some commercial bifold doors use a strap system and some use a cable system. The straps or cables are located close to both outside edges and in the centre of the door. As the door rises, the cable or strap pulls tight to keep the door at a certain level and hold the door in the upright position when fully opened. The top of the door is hinged to the building and the very bottom has pivots on the sides that go up and down in a track installed to the sides of the door frame.