Hello all, I’ve been mulling over designs for a few days now trying to come up with something that could take what I learned from the first design but mitigate community concerns regarding size and general nuisance factor.
MANTA-STAY Pros:
- Very even distribution of pressure
- Easy to apply
- Mild compressive force
- Wide, rounded contact faces
MANTA-STAY Cons:
- Size
- Multiple Components = Assembly and Tolerances
Ultimately I wanted to move the design back into a the footprint of something like the Aculief crimp or chip clips from Pilgrimsmaster’s post without losing the pivoting faces.
My fiddling lead me to the idea of 3D printed springs, which I had considered before but disregarded because I believed resin to be too brittle to achieve any functional spring design within a reasonable size constraint. I decided to give it an honest attempt though, as the utilization of compliant mechanisms promised a single part at worst, and a smaller part at best.
My first attempt was done using a cross axis pivot similar to the top figure in this image;
Resin did prove to be too brittle for this application, and I instead came up with two designs using variations on living hinges instead. The resin is too brittle for these to function as actual hinges, but just flexible enough to provide some spring.
The video at the bottom of this post shows the first print of these two designs. Both seemed to function as intended, though still had obvious shortfalls, especially when placed on the hand.
The first design, using the horizontal, snaking hinge did not have sufficient depth, though it did maintain a nice spring. This is even with me overlooking an error in print orientation where the burn in layers caused the spring to fuse on one side.
The second design with the three slanted springs gave really nice motion, but was ultimately still too stiff, and I think can be shortened further.
I plan to continue with both of these designs until one proves superior (or I think of something better), likely whichever achieves functionality with the smallest footprint. You may also have noticed I did away with the opening tabs. This was a space reducing measure, the tabs proved themselves unnecessary as I fiddled with the crimps. There is an easy way to apply them without the tabs.
