How to make Mechanical Iris Diapraghms?

[Otto Von Pifka]

just a passing thought on the beer can iris....

if you were to make a second pin hole to the rear corner of the metal, the corner furthest from the center when its closed, and link each hole to the next iris along with a connecting shaft, you could move all the leaves at the same time by moving one.

do I make sense? it's pretty late here.

[stockton_joans]

on the subject of irisis onb goggles i was wondering if you fine fellowes (and ladies) could offer some advise on the construction of my gogles.

i want to have an iris over the left eye and a jewlers loup hinged above the right whith some sort or mechanicical doo-dad that would close the iris as the luop was lowered, any ideas f it could work and if so, how?

[elShoggotho]

If you manage to connect the loupe to the external (adjusting) ring of the iris, it could work, but the only way I can imagine would be a bulky pulley system. Better to adjust it manually.

[Affian]

I made a pair of goggles with an iris in the right eyepeice with a camera's apature iris. It's construction was the same as mentioned above, just smaller.

Lens

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You can see the arm and spring that controls the iris down the bottom

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[Lucian Lidgett]

Tremendous!

[Robo Von Bismark]

I do like the idea of variations on irises, such as animal eyes. I am working on a simplified version of this earlier one I made. Using only two shutters instead of the twelve, Im hoping it will look like an almond eye







Another simple variation could be this 4 door design I did as a mockup. Plan to make a bigger version eventually.

[JingleJoe]

Mr Bismark, would you happen to have any further information on the assembly of that iris? It's just the kind I was looking for

[stockton_joans]

there was a link posted in this topic but their prices are quite high, and they dont look that steamy, you'd probably be better off comisining one of the forum members to make one for you

[Robo Von Bismark]

Mr Bismark, would you happen to have any further information on the assembly of that iris? It's just the kind I was looking for

I really need to scale down those pictures. Sorry about that folks

JingleJoe most of the info is here:

http://brassgoggles.co.uk/bg-forum/index.php?PHPSESSID=4ec7d5220eb53a13750e0f9050ca5257&topic=5079.15

If you need the original template file I created I can email it to you. Its EPS vector format, so its easily scalable in Illustrator, Coreldraw or AutoCAD.

The most important thing to get right is the shutters. I cut them from steel and brass shim (about 0.35" i think). The studs were made from nails that i hammered through the shim. This ensued a tight fit and a bit of support along the nail shaft. I then cut the nails at both ends, leaving about 5mm sitting in the hole. The 5mm nail was the pushed flush against shim face and a blob of epoxy putty smeared over the surface to secure it. This has to be smooth to ensure that the shutter works well. Also helps if you sharpen the edges of the shutters for a smooth action (a dremel tool is good for this).

When I do my simple two shutter "eye" version I hope to explain this better with pictures.

[stockton_joans]

is there a specific ratio for the size of the blades in relation to the size or the rings?

[Robo Von Bismark]

is there a specific ratio for the size of the blades in relation to the size or the rings?

Was this a question to me? Depending on style the ring is usually one third the thickness of the iris. I have tried to find a design with a thinner ring.

[stockton_joans]

it was an open question to the board.

is that one third of the entire thing, as in the outer third being the ring and the inner two thirds being the iris or is it one third of the size of the iris itself?

i hope that makes sense to people who aren't me

[Robo Von Bismark]

it was an open question to the board.

is that one third of the entire thing, as in the outer third being the ring and the inner two thirds being the iris or is it one third of the size of the iris itself?

i hope that makes sense to people who aren't me

Its one third of the entire thing.

[stockton_joans]

woo-hoo, the rambalings in my head meat made sense, also how wide do the blades need to be in relation to the opening etc?

[Robo Von Bismark]

This is the diagram i used for my twelve blade monoggle. It was traced from photos from the internet.

[stockton_joans]

i take it on the cam wheel the lines are grooves in the ring

[Prof. Ichabod]

Hola, I have been scouring the aethernet for aeons, and have found this: http://yioryeosa.deviantart.com/art/Mechanical-Iris-43247470. I hope you can all make heads and tails of it, for I have managed to take only a little from it. But it does seem very good.

[nathe]

Hola, I have been scouring the aethernet for aeons, and have found this: http://yioryeosa.deviantart.com/art/Mechanical-Iris-43247470. I hope you can all make heads and tails of it, for I have managed to take only a little from it. But it does seem very good.

dosent look like it would work to me. the slots on the cam plates are equidistent from the point of rotation, so it actually wouldnt be able to turn at all, and the iris blades would be free moving and not actuated by the cam plate. if you were to offset the cam plate slightly, and reduce the distance between the rotation point and the point of contact with the cam plate, you could make it workable.

[roytheodd]

While Googling "brass 'iris diaphragm'" I found these exquisite brass camera lenses. Not a helpful link, but nice eye candy. 

[Professor Fzz]

Hola, I have been scouring the aethernet for aeons, and have found this: http://yioryeosa.deviantart.com/art/Mechanical-Iris-43247470. I hope you can all make heads and tails of it, for I have managed to take only a little from it. But it does seem very good.

dosent look like it would work to me. the slots on the cam plates are equidistent from the point of rotation, so it actually wouldnt be able to turn at all, and the iris blades would be free moving and not actuated by the cam plate. if you were to offset the cam plate slightly, and reduce the distance between the rotation point and the point of contact with the cam plate, you could make it workable.

I agree it wouldn't work.  With the curved track shown, you could move the blades without turning the cam plate.  Indeed the text accompanying the picture says:

"The Actuating Ring; is the part that is moved to open and close the iris. It has an elongated opening that functions as a guide rail to move the blades. NOTE!!!; I'm not sure if these openings should be straight or curved. But i've drawn both of them just for good mesure."

Then he follows up with:

"After some more contemplation on the subject of the shape of the rail in the actuation ring i think that the best shape is a straight line between the inner and outer position of the sliding axel.
The longer the sliding rail the longer it will take to close but also it will be more powerfull in its motion."

In fact you probably want it straight, but slanted the opposite way from the way shown.

[nathe]

yeah, as far as i can see, strait slots in the cam plates, running radially is the best design. slots slanted toward the pivot will cause a faster movement, however slots can only be slanted towards the pivot to the point that the mid-point of the slot is at a normal to the centre of the pivot, any more and it will lock up. slots slanted away will cause a slower movement.

"After some more contemplation on the subject of the shape of the rail in the actuation ring i think that the best shape is a straight line between the inner and outer position of the sliding axel."

this is actually the limit that you can get to. it will be very unstable and prone to locking up with this configuration. a less of a slant however will be workable

curved slots* would give you a variable speed, i have no idea what you would use that for.

*this would only work where the centrepoint of the curve is not on the same curcumfrence as pivot. any more or less then concentric would change the direction you have to move the cam

***btw. it looks to me that the slots are concentric with the pivots, i am working off this assumption

[rogue_designer]

curved slots* would give you a variable speed, i have no idea what you would use that for.

When used for photographic purposes, the variable rate allows you to have your f-stops on the control ring marked equidistantly, while the curves accommodate the change in rate required to get the actual aperture to the correct diameter (not a linear progression)

[Derranged-Gadgeteer]

I've just had the most spectacular of ideas and I need a piece of information...

Is there a design of mechanical iris in which the blades do not overlap at all?  i.e. where each edge of each blade is in contact with the two adjacent edges of the adjacent blades.  And if so, where may I find the requisite proportions?  It needn't close completely, just mostly.

[Judicator]

I want an iris so bad.....It can be for anything,goggles,a gatling gun,a door,a car.....

[Robo Von Bismark]

I've just had the most spectacular of ideas and I need a piece of information...

Is there a design of mechanical iris in which the blades do not overlap at all?  i.e. where each edge of each blade is in contact with the two adjacent edges of the adjacent blades.  And if so, where may I find the requisite proportions?  It needn't close completely, just mostly.

Do you mean like this?

http://brassgoggles.co.uk/forum/index.php?topic=15364.0