Why do door knobs still exist?
As far as I know, in US, grip-and-turn style door knobs are still the most popular, as opposed to lever-style handles, which dominate in the rest of the world.
Is there some UX advantage to door knobs that I am not aware of, which is the reason for keeping them around?
To clarify the difference, this is the grip-and-turn door knob:
And this is lever-handle style:
Do you have any source concerning the "dominate in the rest of the world" part? I'm pretty used to "grip-and-turn" door knobs in France too.
They make for excellent plot devices in low budget horror films since it is hard to open them with your hands covered in blood
@ArlaudPierre, Not, sorry. Just my subjective impression. I'd be very keen to see any statistics on the subject too.
Same [email protected], I am surprised to hear grip-and-turn door knobs are the norm anywhere to be honest. Only on front doors I have see them from time to time for aesthetic reasons.
You rarely see any grip-and-turn knobs in germany. And if you do, they even seem to be confused with knobs that you can't turn at all. Those unturnable knobs are quite frequently used on the outside of front doors or doors without a snap/latch lock.
In the US, grip and turn knobs are used in virtually all _homes_, while lever style are often seen in offices. So we are very familiar with both types.
I'm interested in hearing how levers have a better UX than knobs. I find that knobs are much easier to use because you can turn then very quickly without having to mount your hand in a specific way on a lever.
@Keavon: How do you open and close a door with a knob from both sides when you are carrying something with both hands?
@MichaelHampton, This is largely due to the Americans with Disabilities Act, which recommends against doorknobs in favor of lever handles, and applies to businesses but not to private residences.
FYI, I had to replace my lever style bedroom door knob with a grip and turn version because the cat figured out how to jump up, pull the lever and bust into the room. He liked to come in mostly at times when the door was closed for a reason.
Not a UX answer, but a practical one. When installing in some doors, especially those with large lock mechanisms (generally much older ones), it can be difficult to get a door knob screwed firmly enough to the thin wood (or whatever the door is made of) left either side. The larger plate associated with most lever-type handles easily 'bridges' this lock part and allows for screwing into the solid wood either side. Grub screws to hold the door knob to the spindle mitigate this only partially.
I wanted to mention that I can open a door with lever using my butt only. But I also wonder why in some doorknob cultures, they tend to put the knob in the *center* of the door? Of course that looks more symmetric, but this doubles the force nneded to open and sometimes you cannot even guess beforehand which way the dorr swings ...
There is also a compromise: an egg shaped knob that is still mostly round, but is easier to grip for people with lower grip strength. It has the huge advantage of not being easy for cats (or dogs, bears or velociraptors) to operate, and not being as prone to hooking clothing as a handle. (I had a door that ripped my pants clean off me once. I hate handles.)
@HagenvonEitzen: You can open an inward-opening (from your perspective) door with a lever using your butt only?
@benPearce: Exactly - or one that is somewhat stuck and thus requires some greater force.
When it comes to building/construction, it's usually just tradition. If it wasn't for inertia and tradition, we probably wouldn't see doorknobs as much as we do, just like we wouldn't see separate Hot/Cold taps in UK bathrooms (Not to mention cars driving on the left).
No-one has questioned the visual appeal of knobs vs doors? Maybe they just look better!?
It's all fun and games until the velociraptors learn to open your lever-handle doors.
I've hurt myself with a handle before. I've also had clothes get stuck on handles before. That's never happened with a knob.
I have never caught my sleeve on a traditional door handle, however it would seem my sleeve always catches on levers
What about child-safety? While the eyes of a child are at the same level as the lever, they are in serious danger. There are some very serious accidents where childs are losing one of their eyes from it.
@styu: Aren't the eyes of a child just as well on the same level as a door knob?
Door knobs are standard in US homes for the same reason that exterior doors open inwards* -- it's "always been done that way". People grow up used to knobs, and specify knobs on new work, and thus this inferior mechanism is perpetuated. For some buildings (not private homes), some building codes now require lever mechanisms so that the handicapped can operate them more easily. In most buildings with high occupancy (schools, commercial space), outward-opening doors with crash bars are required. These codes came after some tragic fires, where people piled up against inward-opening doors.
I don't see lever mechanisms and outward-opening doors becoming common in US homebuilding, unless codes are amended to require them. Considering how much pushback there has been over incandescent lightbulbs, I don't see that happening any time soon. Maybe if there is some sort of "handicap accessible" certification that would make a home easier to sell, that would encourage the change.
* originally in colonial homes, doors that opened inwards could be barricaded from the inside to prevent hostile attackers from breaking down the door. The tradition has continued to this day.
More on why doors open inward in homes here: http://home.howstuffworks.com/home-improvement/remodeling/question584.htm.
I'd be curious to see a citation on the last bit about colonial homes. It seems like it would have to do with any hostile person, not just Native Americans, and would go back further than colonial times.
Looking around for a citation, I saw suggestions that 1) in snowy areas an outward-opening door could trap you inside (and code thus requires inward-opening in some areas), 2) hinges on the outside can have their pins driven out by a burglar, 3) the wind can catch an outward-opening door and damage it. But I do remember being told long ago about being able to barricade an inward-opening door. I will try to find an acceptable citation.
In the US, lever handles are usually a _recommendation_ by the ADA. Crash bars (when present) are usually a _requirement_ by the OSHA.
Our home, in Minnesota USA and built in 1976, was originally equipped with levers (and still is).
The usefulness of lever knobs seems way overblown to me. They don't help "when your hands are full" except on doors that open inwards. And even then, only if the door does not require a key. Most levers are horizontal, which is mostly ergonomic when pulling, but not so much when pushing. There are advantages for levers if you have limited grip strength, though you're also more likely to be hooked by one. And most levers are not designed for safety or ergonomics but to look good.
I find levers to be the inferior mechanism for my usages. As mentioned above, levers are not helpful with hands full and can even be worse because the release points on the current lever sets are all too far down, making it harder to open than with a knob. Pulling doors closed with levers twists the mounting points (since the point the force is applied to is not centered, unlike knobs where it is), leading to loosening/early failure/breakage. Levers are great for snagging pockets/bagging clothing and tearing it.
to be fair, doors that open outwards are harder to break down since the entire frame around the door basically prevents the door from opening inward at all.
@Wayne: Can you turn a doorknob to open an outwards-opening door with your elbow, while your hands are full? And how many interior doors within your house do you actually ever lock so opening them would need a key? Also, can you elaborate why levers that are between horizontal and 45° turned are not ergonomic for pushing?
@BrianKnoblauch: Actually, levers *are* helpful with hands full. With hands full, a door with a door knob is impossible to open or close, but that's well possible with a lever, just using one's elbow, for example.
@DavidRicherby: You cannot close a door that opens "away from you" by "pushing". But, yes, exactly my point about how to open and close doors with levers with the elbow.
I always thought that part of the reason why residential home front exterior doors opened inwards was to allow for secondary screen/glass doors. This would be a more "modern" change (as compared to the barricading example), but it would still be awkward otherwise with an outward swinging main door.