Spring door closer

[daccel]

I salvaged 4 door closers like this one at a jobsite where they were being replaced a while back and finally got around to opening one up to see how useful it is.

The only one I've seen on the site so far is in a springer cannon.

Definitely looks like it could be useful to make a pump, fueling component or chamber.

The tubing is welded, but smoothed out on the inside so the o-ring can seal.

The piston is interesting, it uses what looks like felt on one side in a floating o-ring set up.

Just thought I would post this up for reference for anyone else who might find a use. You can pick one up new for ~ $15. This was pulled out of a pretty old building, but I can't imagine they've changed much over the years.

[kenbo0422]

You could try gas springs. They work on a high pressure applied to both sides of the piston, with an equalization hole in the piston. The spring always goes toward the side with the rod since that side of the piston has a much smaller exposed area and has less force. The equalization hole keeps the movement restrained and allows the gas to continually equalize during movement. What a nifty idea. It only works with the higher pressures inside the tubes, though.

These, that you have would make a good recoil absorber (use at least 2), like the old WWI cannons had.

[twizi]

u could make a shock pump just a thought


i just noticed that this was a months old, blame the noob

[kenbo0422]

Yup, blame me. I read these things and see that nobody seems to want to answer the questions, or things are still pending, or the originator hasn't acknowledged anything. People can't get much help if nobody's talking, so, I'll do the unthinkable, I'll post on old subjects.

Help and collaboration are what these forums are for, right?

My join date is older than yours...

[jackssmirkingrevenge]

Help and collaboration are what these forums are for, right?

Precisely, I find no objection to old topics being kicked up if the one doing the kicking has something valuable to add to the discussion.

[inonickname]

My join date is older than yours

Twizi is indeed a very odd man. In fact, I'm the noobiest here..

[Hubb]

Yup, blame me. I read these things and see that nobody seems to want to answer the questions, or things are still pending, or the originator hasn't acknowledged anything. People can't get much help if nobody's talking, so, I'll do the unthinkable, I'll post on old subjects.

Help and collaboration are what these forums are for, right?

My join date is older than yours...

I've been reading all of the bumps you have and I have no objections. You seem to be knowledgeable (and know how to search) so I'm sure the Admin wouldn't mind either.

[kenbo0422]

My first cannon (1977) was duct taping several old coke cans together (tops and bottoms removed, and before the one piece w/ top crimp designs) with one on the end not hollowed except for the top was punched through several times. The bottom was punched with a small hole. You put lighter fluid in it, rolled it around, loaded a tennis ball and hoped it would work. It did.... Put a tennis ball about 200yds down the middle of a city street (ours). The duct tape held well, never did break. That was my first taste of homemade ballistics and I've been doing stuff on and off ever since.

The closers are great for absorbing recoil and even helping to 'pressurize' a chamber (the gas springs, in this case). With a detent or lock, it won't move during combustion.

You could use it as a piston rod: it plugs the end of a chamber cylinder. When the gun is fired the gas spring extends and pushes out the spent air with the help of a couple of valves. Refilling the chamber with a pressurized mix pushes the piston back. Venting becomes almost an automatic process, without a fan.

[POLAND_SPUD]

@kenbo
you don't really need a spring door opener to do that.. adn the idea has been mentioned a few times before... but IIRC no one has tested it yet so you can be first