Picture of Counterweight Door Closer
Hi, everyone! Welcome to my first instructable! I hope it will be helpful to anyone who wants to make an automatic door closer with this design, using sheaves and internal counterweight. I'd like to apologize for any grammar or english errors, because i'm brazilian and i am also trying to learn english while publishing some few ideas that i was able to put in practice!

Well, let's go to the instructable:

Bill of Materials:

Well, I didn't take any picture of all the material that I used in this instructable, but here is a list of the most important that were used:

   -> 0,5m of " U" Beam (35x10mm) for office divider panels;
   -> Two 50A1 sheaves (Diameter 50, A1 channel);
   -> One 60A1 sheave (Diameter 60, A1 channel);
   -> 2 pieces of M8x50 DIN933 screws;
   -> 14 pieces of M8 DIN934 nuts;
   -> 2 pieces of M8 DIN125A washers;
   -> 1 piece of M8x95mm cut of threaded rod;
   -> 2m of wire/rope. I used clothes line rope, here;
   -> 6 sets of 6mm steel screws for concrete fixturing;
   -> One bottle for counterweight.
   -> 6 pieces of aluminium rivets 3,2x12,7mm

Materials left to get other level of finishing:
   -> 700mm of sewer PVC pipe of 75mm diameter;
   -> One cap of 75mm PVC sewer pipe.


Tools that I needed to make this instructable:

   -> Power Drill
   -> 8mm concrete drill bit
   -> 3,5mm HSS drill bit
   -> Angle grinder for cutting the "U" beams;
   -> Hand riveter for 3,2mm rivets;
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boardsmm1 year ago
Hi Fernando and thanks for this!
Here's a more rational design (I think):
Skip the Return sheave and simply twist the Couterweight sheave 90 degrees to the right and stick it to the other wall. And shorten the string of course.
Again, thank you!
vanwazltoff2 years ago
me and my brother built something similar a few years ago, we had to close the door the opposite way, used fishing line for a bungy effect so when the bottle reaches its lowest point the line flexes a little and doesnt send it crashing into the wall. we used a mountain dew bottle filled with pennies and drilled a hole through the top of the bottle instead of just tying it so it would come down straight, room air pressure [whether the window was open or not] was an obstacle because if the window was opened the door would slam so we had to have a small spring between the door and the jamb so it wouldnt slam
wgrube2 years ago
Good job! Just a suggestion, could you describe the inverting sheave a little bit more in detail?
3dfernando (author)  wgrube2 years ago
Thank you! Of course, here it is below:

Let's suppose that you didn't have put that sheave. Then the rope would have to connect directly to the "return sheave", and it would cause it to face towards the wall opposed to the door.
This way, when the weight falls down, it will generate a tension force on the rope that would, in the point where it is fixed in the door, point towards the inside of the room. Then it would open the door, not close it! And my mechanism would so be called "Automtic door opener", hehehe!

So I had to put that "inverting sheave", that will make the rope tension force point towards the outside of the room, in a way that it closes the door.

Let's say that you had put the mechanism on the other room, then it would not be necessary, because the tension force is already pointing towards the closing movement of the door.

Hope this explanation helped you!
HickLife2 years ago
i've done that with a few doors i built in Afghanistan, except waaaay simpler, just a couple of U nails and some 550 cord and some water bottles. is simple and it works, just dont get your hand caught in it it doesnt feel too great
Azzurro2 years ago
I did the same in my dorm room at university. Epic. :)
islandsolar2 years ago
Can you post another video. i cant see whats going on here.
Manny B2 years ago
Very nice. Simple and effective design.
Nice work...

Am i the only one who instantly thought of ferris bueller's day off?
giles26062 years ago
This is a nice complication, and very impressively executed (great instructable!! :-) would be simpler with the rope attached above the door, and a pulley/sheave on the top edge of the door, with the weight hanging down the back of the door.

This way does allow you to put the weight in the corner and more out of the way however.

Good work,

The weight next to the door means it will knock against it.
I know what you mean, however when I tried it, the weight rarely hit the back of the door. That does not seem to be intuitive (according to my level of physics anyway), but you had to push the door really hard/quickly in order to make the weight hit the door.

However I would agree that the solution here, although more complicated, is a much neater way of closing the door.
espdp22 years ago
We used to do that for all of our doors when I was in Iraq to keep our cool air in, but yours works and looks much nicer. We would just drive a nail halfway in, and then bend it into a hook. Also, I think we had our water bottles on the other side of the door so they would close all the way, but they tended to make the door bang shut. Good work!
AndyPipkin2 years ago
Cool, I use one of those stretchy curtain cables, it's like a long spring in a white sleeve, a screw hook in the door frame by the hinge and a screw eye in the door on the handle side, both at the top of the door it does close a bit quick and the girlfriends dog gets stressed when it's head gets stuck :/
Caspar2 years ago
I made a similar one years ago using fishing line, pulleys from an old radio (the tuning dial mechanism) and two "D" size batteries as the weight. Three would have worked better, and when someone commented that it did'nt work very well, I said it was because the batteries were flat. ;-)
leea92 years ago
From the photo it seems that it would work well until the last few cm because of the angle and does not hold the door firmly closed. How did you get that to work?
criggie leea92 years ago
I'd attach a short stub out from the door so that the string pulls at the same angle the whole time. Could do away with the left-most pulley too.
vincent75202 years ago
Great !…
A nice way to remember us that older easy mechanisms can replace sophisticated expensive engineering …
However, when the soda bottle has been drunken, what happens ?…
Very nice
bettoarias2 years ago
Bom trabalho! Exatamente o dia de hoje minha esposa estaba falando pra mim sobre como manter a porta da habitacao das minhas filhas fechada pra evitar o ingreso dos mosquitos, eu pensei en colocar um fecha-portas hidraulico que tenho por algum lugar da minha casa.. ha ha! pero agora vou fazer uso da sua ideia... Obrigado desde Asuncion, Paraguay, South America.

Good work! Just today my wife was talking to me, about keeping the door closed in my daughters' room to avoid mosquitoes, I thought putting an hydraulic door closer that I have somewhere in my house .. ha ha! But now I'll make use of your idea ... Thanks from Asuncion, Paraguay, South America.
ceanes2 years ago
Well done, i need one of this thing but it is hard to find .

Muito bom, tava querendo um aqui destes que se vê em escritório, nunca pensei que poderia ser feito assim, valeu.
antioch2 years ago
Looked lik a door opener to me until I watched the video ^^
bg_askins2 years ago
Very nice, I had a similar pulley system on my bedroom door growing up.
bertus52x112 years ago
Thanks for sharing this project. One question: where do you get the "sheaves". Is this some part of a machine or can you buy them "of the shelf"?
3dfernando (author)  bertus52x112 years ago
Thanks for the comment!
I bought them on a hardware store, here in brazil, it was very cheap (about $5 each). These are single channel pulleys for "V" belts, I think it is easier to get there in USA than here!
ghaom2 years ago
Would not the project work better if the door swung the other direction? However the demonstration of the theory is marvelous.
3dfernando (author)  ghaom2 years ago
Thanks for the comment! Surely it would be easier if it was on the other side, but in my case it was impossible because I couldn`t invert the door. Also, this way the counterweight stays hidden behind the door while it is being opened, preventing accidents while it`s moving.