The late Dr. Brian Mar was fond of using “open the door” as a function exemplar. He’d usually measure it with “how fast?” and “how far?”. Years down the road, I still loose sleep over it. There are many more topics associated with the problem:
- What’s the maximum speed? Is there a maximum acceleration?
- Is there a limit on the inertial properties of the door?
- What’s the shape of the opening?
- What has to be precluded when the door is closed? Is it keeping things out, things in, or both? Is there a sealing requirement?
- What has to pass through when it’s open? Do the seals (if any) need protection?
- How long should the door stay open?
- How fast should the door close?
- If it opens against something, what should it do?
- If it closes on something, what should it do?
- When its closed, what loads should it resist?
- Is there a limit on the actuation load in either direction? How about the unlatching force, if any?
It turns out that doors are not near as simple as he led me to believe!