I'm just wondering if anyone has actually tried to build this iris diaphragm from the NASA technical paper. If you read the paper, the idea is ingenious. There are five blades in front, and five blades behind, (there are, in fact, ten blades) and closure is complete, as is required for apertures in space. However, I've been trying to adapt this design to build in wood, and it is difficult to determine the source of the curves in the blades. Similarly, it is difficult to design, without these curves, an aperture that works, in wood. If anyone has similar drawings for this aperture that they were able to make work, I would be most appreciative. I'm attempting to design a ten bladed aperture, using a similar model of five blades behind and in front (to reduce friction) and my overall size is 24", or 609.6mm. I'm thinking that a practical sized full opening (maximum aperture) using this sliding ring mechanism would be about 14", or 355.6mm, to allow enough space for the blades to exit. The other advantage of this design that I like much better than many of the other sliding blade options is that very few degrees of turn are required on the actuating ring in order for complete opening or closure. The reduced friction by having less (or ideally no) overlap on the blades is also something I'd like to achieve.
I'm interested to hear others thoughts.
Cheers,
Lori
Oh, I just love mechanical irises. For a door though, you'd probably need one that could close completely - I don't think the design in that figure can close completely. Here's a slightly different design (from this article) that can close completely. The figure only shows five petals, but you obviously need ten.
I've been thinking for a while of making shutters for my study using an iris design - one of these days...
- Fzz
