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October 2, 2014 / paulio10

Door Stops Done Right

Here are some needs that we all have, but nobody has solved it in the right way yet.

Need #1

You open the door of your house. Because of the way it was oriented when it was attached to the house, it’s a tiiiiiny bit off-axis, so the door always swings open to the maximum amount; you can never leave the door open half-way.  Or, it angles the other way, so it swings closed always – you can’t leave it open half-way, or all the way – it always closes on you.  If only there was some kind of hinge-goop you could add that would increase the friction within the hinge a tiny bit, like, the opposite of oil, whatever that could be. You want to avoid making the door hard to open and close, and you don’t want it to start squeaking; just something to counteract ghostly-swinging-door syndrome. You know, like how a laptop lid can be tilted at any angle and it stays there – successfully fighting gravity’s pull on the screen – how do they do that? The laptop lid doesn’t slam shut, it stays at any angle. And over time it never loosens too much, the hinge never squeaks, even after you’ve used it every day for the past 4-5 years. And it’s such a small device, it fits in a laptop hinge!

Need #2

You probably have a door-stop on your door so when you swing it open too strongly, the door hits the stop instead of smashing and denting the wall or crushing the baseboard. There are 5 types of door stops in popular use today, which I like to call:

* the small door twanger:


* the large door twanger:


* the solid metal door stopper:


* the hinge-pusher:

door-hinge-stop        hinge2-stop

* the doorknob wallplate:


At least where I live in the western United States, these are the only types of door stops I’ve seen, and I’ve looked inside probably a thousand houses or more in the past 10 years.

All of these have the same problem: they forcibly bounce the door back in the direction it came from!  That’s never what you want. If you flung the door open, you want the fucking door to be open, at least for now. Why would you want it to spring back in your face with near-equal force to the one you expended to propel it open in the first place?  That’s just ridiculous, and is a huge source of additional irritation when you’re already irritated after coming home from a long day of pointless meetings at a corporate job.  (OK, that’s me; maybe not you).

Look. You want the wall to absorb all the momentum of the door and throw it away, so the door doesn’t have any impetus to bounce back with – no matter how weakly or strongly the door is cast open. It turns out we’ve already invented this kind of device, in fact you have four of them on your car. Every car has them. They’re called shock-absorbers. There are two parts to a shock absorber: a spring, and a strut or dampener. The idea is that the spring counteracts the energy coming at it exponentially – the harder/faster the object is going that compresses the spring, the more the spring pushes back. And, if you put a LOT more energy into the spring, it only compresses a little more, not a lot. So the movement can be completely neutralized within a small distance.

Everybody knows what a spring is, a coiled bendable metal wire, that can be compressed (in this case); it retaliates by pushing back in an attempt to return to its former uncompressed shape and size.

The kind of strut or dampener I’m talking about is sometimes called a Dashpot (wikipedia article).  You don’t have to use a fluid for the medium in the dashpot, a lot of successful “gas springs” just use air for the medium, rushing around/between metal cylinders to provide the dampening action. Air-based struts are probably better than oil- or water-based ones, so that there’s nothing to leak out or evaporate away over time.


Now if all you use is a spring, you have the problem that all the energy stored into the spring will be pushed back onto the thing which compressed the spring to begin with! That’s the problem we have today, the problem we’re trying to solve.  The secret to solving this problem is to add a strut/dampener to the system. This thing slows down the momentum both when the spring is being compressed and when it’s extending back out again. If you choose the right spring & strut for the mass & speed of the moving object you want to dampen, like a front door swinging open, then it will be able to completely cancel out the energy of that swinging door no matter what speed is used to thrust it open.

You need both the spring and the strut, just like each of the 4 corners in your car, to solve this problem properly.

Failed Design of the Common Door Stop

If you carefully examine the two twanger-style door stops you’ll notice something interesting: the rings are already compressed as far as they can be without overlapping each other! This “spring” has no spring in it! It can’t compress, it has no where to go! That’s just a faulty design right there. As long as the door is not thrown open too hard it kind of absorbs some of the energy, and kind of throws the energy back into the door; at no time is the springiness of the metal wire being used properly.  If the door is thrown open harder, the entire thing bends at a 90 degree angle because there’s no guide controlling the direction of compression. Congratulations, it’s permanently damaged; it doesn’t spring back anymore. Time to blame yourself, as if it was your fault for opening your door too hard, and go buy a new one at the store.  That is so, so Lame!

We need a springy-spring, that’s able to absorb the right amount of momentum in a short distance (let’s say 1-2 inches). And, we need it wrapped around a dampener that can completely dampen all the energy of a solid wood door thrown open at the highest speed the human arm can swing it at.

How much fun would it be to come home from work, and SWING open that door as hard as you can, knowing you won’t be damaging your house?  Seeing/hearing the spring and dampener kicking in, protecting the house from your over-energetic arrival to your home?  It might feel good to do that.  Maybe we should also build in a sound-effect that’s louder/stronger the more momentum is applied to it – so you get a feeling of satisfaction from throwing open the door as hard as you can. Why not? It’s not hurting anything.

This kind of device should be fairly simply built with low-cost materials, so that it doesn’t cost too much when you buy one for every door in your house – inside doors and outside doors. I want Home Depot and Lowes to sell them for a nice low cost in a 4-pack perhaps.

I can tell you I’d buy at least two dozen of them, put them in my house, my rental houses, and give them away to my friends as holiday presents. Because, nice! Something actually improved in our world.

Today’s Shock Absorbers for Doors

The current shock absorber designs for doors are pretty lame. That old-looking 2-foot-long cylinder mounted across the top of the door/frame, with one metal rod bolted into the wall, the other end fastened onto the door, with pivoting hinges. It was designed in the 1960’s or earlier. You see it sometimes in industrial locations, offices and schools, when big-heavy doors are involved. Some of them work decently, pulling the door closed strongly without letting the door slam shut – the dampening occurs in the last few inches of the door being closed. But a lot of the time they don’t work right. They fight you if you want to prop the door open. Plus, they cost between $150-300 retail from what I’ve seen on the Internet. That’s too expensive.

I don’t want something big and obtrusive like that. It needs to be small and contained, and located down low, like where the twanger style door stops normally are mounted these days. Besides, it shouldn’t fight me opening the door; the goal is to stop it slamming open, who cares if the door slams shut?

Building A Better Door Stop

With a little more design and consideration of low-cost parts, a really good Door Shock Absorber should be doable without too much effort. The parts should be simple enough and small enough, and the cost should be low enough that people can afford to put them on every door in their house. I wish I had time to design and build a prototype. Whoever actually runs with this idea could make a lot of money.

Future View of Houses

Everything in our house should be able to be used for many purposes. Every towel-bar should be able to support the weight of the heaviest human being on the planet. Because every little kid wants to do pull-ups when they see them! The first time you try it you break it, and mommy or daddy yells at you. This is no way to live, decade after decade from when the problem is discovered! Understand the problem and fix the fucking issue once and for all. Because, why not! A house should be indestructible. You should be able to do anything you want with nearly everything in the house. Why not!

What else should be stronger than it is, today? Why are we still using breakable windows? There are many materials just as clear as glass, that don’t shatter and endanger your family and pets with sharp shards that can bleed you and send you to the hospital. Another totally ridiculous way to live.  Decades and decades later, we still haven’t yet done the first step to fixing the problem. Let’s fix that shit.


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