Friday, July 13, 2007

The Four Way Door


A door that can open four different ways.

I wondered 10 years ago if it was possible to create a door that opens 4 different ways. We've of course seen doors that swing in or out on a double way hinge. I figured there should be a way to build a door that, regardless of whether you were inside or outside, you could push either the left or right side of the door and it would open. Not only that, but the door would swing open as a door should intuitively swing... not merely pivoting in the center.

This is the design that I came up with, and have done nothing with all that time. One of many ideas that I will eventually publish here.

There are many Rube Goldberg ways to accomplish an opening door based on pushing any one of 4 areas on it. This was the simple way that I came up with after chewing on the idea for a while.

At rest, the door's hinges are rods that jet out of the top-left, top-right, bottom-left and bottom-right, engaging into the frame so that the door is essentially "locked" in place. Consider this just as immobile as adding conventional hinges to both sides of the door.

The pedestrian (user) is expected to approach the door, then push on either the left or the right side. There are many doors with wide recessing "push panels" that disengage the door latch to open the door. This idea uses a panel that pivots in the center so that when pushed on either side, the mechanism behind that side engages.

When the right side of the door panel is pushed, the right-side mechanism retracts the right-side hinge rods, allowing it to swing on the remaining left-side hinge. The door must also be prevented from "falling out" of the frame due to a curious pedestrian then pushing the other side. The answer is to engage a lock on the opposing hinge. When the right-side mechanism retracts the right-side hinge, the left-side hinge rods are locked at the normal full extension until the door returns to the resting state, and all four hinge rods return to full extension.

Normally, some sort of automatic door closing mechanism would be added to the door to ensure that it returns to its closed state once a person walks away. The normal mechanisms mounted on left and right sides would seize a 4 way door. One solution involves a semi-attached version of the conventional slow swing hydraulic mechanism. As the door opens, an extension of the door pushes one of four hydraulic arms out, which slowly returns the door to its closed state.

Gravity could also be used as a simple mechanism for returning the door to a closed state. When the door is opened, the door's construction where the hinge meets the frame causes the door to slowly rise as the door is opened wider. With the door's weight working for us, the door wants to drop back into the hinge/frame groove, which causes the door to close.

When the door returns to the closed position, the springs in the retracted mechanism and tapers on the rods will cause the rods to re-engage back into the frame. The door would then be back in it's resting position, and ready for the next pedestrian to walk up and randomly push one of the door's 4 pressure points to open it again.


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