Pop Up Warning Sign - Bikes on Roof

thingiverse

Tired of yanking your bike off its roof rack by crashing into your garage door? This design aims to put an end to mangled bikes everywhere. A sign mount clings to your car's hood with magnetic strips. As you speed along, airflow folds the sign shut. When slowing down or stopping, springs pop it open, reminding you that your bikes are still perched on top. Additional parts required (with links): (3) 7/8" long, 1/8" diameter dowel pins (http://www.mcmaster.com/#90145a474/=10ru635) (2) 90 degree torsion springs, .235" OD, .025" wire, left- or right-hand wound (http://www.mcmaster.com/#9287k67/=10ru6kf) (27") 1" wide, 1/8" thick, adhesive-backed, high-pull magnetic strip (http://www.mcmaster.com/#5769k82/=10ru84r) Model Notes: I've included parts with both tight tolerance dimensions and lower tolerance dimensions for the dowel pin holes (it was necessary to add a bit of slack to the holes to get the pins to fit smoothly). The same goes for the offset of the letters. If you want to play it safe, start with the tight tolerance models and carefully enlarge the holes or shave down the edges of the letters if needed. The top, base and letters are printed separately, then the letters are glued onto the top panel using crazy glue or ABS slurry. For those with dual extruders or wishing to hand-paint the letters, I've also included models with the letters already in place on the top panel. Printing Notes: I used ABS for my prints. The layer height was set at .2mm, and the infill was 25-40% (to add some weight to the panels). Letters were printed face down for a better cosmetic finish. Assembly notes: As mentioned above, the letters are glued into place on the top panel. Cut the magnetic strip into 9" sections and install them three-wide across the underside of the bottom panel. Use dowel pins to secure the panels together; install the springs on the two outer hinges, threading the dowel pin through the center of each. Print Settings Printer Brand: RepRap Printer: Makerfarm 12 Rafts: No Supports: No Resolution: Printed at .2mm height with a .4mm nozzle Infill: 25%, 1mm thick top and bottom layers Notes: I used a brim when printing the letters, which may or may not be necessary.