N95 Mask Strap Tensioner

thingiverse

Overview ==================== I spotted an appeal for something to assist tighten straps on N95 masks that were loosening from reuse in a [request](https://www.thingiverse.com/groups/HackThePandemic/forums/thingiverse-challenge-ideas/topic:43972#comment-3390378). Several quick responses popped up, but I believe there are some points they should be addressing. This tensioner is designed to tighten mask straps that go all the way behind the head, not for those with ear straps. It takes up slack by allowing the strap to be wound up as needed in order to get sufficient pressure to achieve a good seal. Design Criteria --------------------- The following are a few of the points I tried to keep in mind while designing the print. * Quick to print * Not prone to snapping (some post-based designs can fail here) * Easy to clean/sterilize * Simple * Avoid sharp edges * Avoid threads and screw-type mechanisms (more complex, harder to print accurately and hard to clean) * Easy to get on and off * Easy to adjust while wearing gloves * Easy to place and adjust while mask is worn Printing --------------------- The design was made for printing at 0.28 mm resolution, but should print fine with smaller values. Be sure to print with 100% infill to get the corner posts solid and strong. The rest of the tensioner will be solid due to being so thin. Post Printing --------------------- 1. Slip the strap behind the top flange. 2. Pull the strap tight. 3. Slip the strap between the posts on one side. 4. Slip the other end of the strap between the posts on the other side. 5. Instead of latching the strap, twist the tensioner to wrap the strap around it. 6. Feed the strap through the posts to gain a little more tension. 7. A single twist gives a bit more tension. 8. Additional twists give more tension.