Well i have decided to share with the world my newly engineered version of an iris diaphragm in the attempts to win a laser cutter, because i have a lack of tools and or money :( i cant make and post a lot of my ideas, BUT i tried my hardest to make this one because i couldn't contain myself any more. so i made it out of easy to use materials i could easily cut with a knife. so if i do win the laser cutter i will be posting more instructables and i will make a better iris diaphragm instructable for you to clearly see how it works.
Basically my new design is similar to the design people all over the world have been using for years in the fact that you rotate either the top or bottom disk to make the iris open or close, also we will be in fact using blades but not even close to the kind of blades we have used before.
However mine is unlike any you have ever seen in the world before, in the fact that it can be any size and have anywhere from 3 blades to...... well how ever many you would need or want, and the over all design would stay the same no matter what. Mine also allows for you to open and then close it completely and when i say close completely i mean you can close it until there isn't any light allowed threw. and to top it all off the blades don't over lap thus creating no friction at all.
p.s. im sorry i couldn't post a video of it working because i just bought a camera i don't have a stand so i had to hold the camera in order to take the pictures but on the next step i will show it closing in each picture.
Step 1: Pictures of Iris Closing
ok well in this step, well its more like a page for you to see me closing the iris a little bit at a time.
Step 2: More Pictures and a Better Explanation
well on this page i will show you that the blades don't over lap. i also show you the different parts to the iris and the fact that it does in fact close completely. so basically this page should have been titled what the insides look like. i will explain how everything works and moves in the next page.
Step 3: How It All Works
OK so the way the whole iris works is that all the blades travel in a straight line back and forth, and the line they travel on is perpendicular to the blades angles bisector. look at the pictures below see how the iris is closed and then when it opened the blade highlighted only moved in a straight line to its right and so did all the other blades as well. these blades all travel in the grooves back and forth. the last picture show a better explanation of the key areas for plotting out how each blade moves angle A is found by first taking the number 360 and dividing it by how many blades you want so lets say 12 blades then that would make angle A 30, as in each blade will be an Isosceles triangle with angle A being the odd angle.
Step 4: Building It
well i don't think i can help much in building yours do to the fact that my design can be changed in size and blade quantity so i will give some pointers on how to build it, if you get stuck on your own just leave a comment and i will help you and or post an added update to show you how to go about doing whatever it is you have a question on. well making slides you can use a groove like i did or even a drawer roller would work to make for blades move nicely back and forth . when starting your build try to first figure out how big you would want the opening to be then figure out how many blades you want lets say you want 12 blades in your iris you want to make triangle with one angle being 30 degrees cause 360 divided by 12 blades equals 30 now you want to make your blades about as long as you opening is wide so for example you want to make an opening of 6in so make 12 Isosceles triangles with the odd angle being 30 and then use the bisector of this angle to measure out 6in like in picture below.
Step 5: Building It
To figure out where to place to slides or rails i simply drew out mine so that they wouldn't over lap each other to make it less likely to get stuck shown in the pic below when placing the slides i chose to put them at the ends of the blades just my preference but you can put them closer to the center of the blade and you could even shorten the blades if you want i'm just giving you a general guide line to building my iris. so if your opening to your iris is lets say 6in then the blade would only have to move 3in which is half the diameter of the opening so to add to this if you figure that your blade sits already 2in on a slide then your slide total would be 5in cause the slide would need to go the extra 3in look at my prototype to see what i'm saying. so once you figure out where the blade will be once it is opened all the way you can now figure out where the outside diameter of the discs will be.
The last thing would be making the pins for the top of each blade you want to put them on the bisector line i chose towards the middle of the blade you can move it either up or down the bisector line. to make the grooves for them it the same as the slides but depending on where you put the pins measure from the edge of the opening to your iris to where the pin is when both opened and closed and plot out a groove the measures the same. so lets say your first pin when the iris is closed measure .5in from the opening or 3.5in from the center of the opening you take this and times it by 2 to get a diameter of 7in you can draw out a circle with this diameter now do the same for when the iris would be open we would get lets say 1.5in from the opening or 4.5in from the center find your diameter by multiplying by 2 again to get 9in this is the distance where the pin will stop so draw out this circle too now you can easily draw out the grooves for your pins by draw out 12 lines 30 degrees off each other because we have 12 blades.
Step 6: Well Thats All for Now
well i think i explained it good enough but hey to me this was really easy to think up and design in my head before ever even building my prototype so i might not have explained something very well if that's the case please do not hesitate to comment i will reply or edit accordingly to help any one who needs it. i just ask that if you like my re-engineered iris please vote for me it would make me very happy and please leave a comment, i appreciate you taking your time to look at my instructables as this is my third one ever and if i can get some more tools to build my ideas i will post more instructables for the many! many! many! other things i have designed in my head.