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3D printed foot door pull

A project log for Hands-Free

hacks to avoid touching shared surfaces in public spaces

John OpsahlJohn Opsahl 03/17/2020 at 04:421 Comment

Doors are probably the biggest opportunity for reducing the number of shared surfaces in public spaces. It's simply not possible to open some doors without a firm grip around the handle or knob. An alternative solution has been to pull the door open with your foot rather than your hands. Several designs are commercially available at around $30 a piece so lets make a 3D printed one on the cheap.

The video below shows how to use a foot door pull. 

I imagine one major disadvantage with foot door pulls. If someone pushes through door from the other side at the same time that you are approaching the door, they might throw the foot door pull into your foot. I certainly wouldn't want to be wearing sandals when that happens.

The commercially available designs are made of aluminum and steel. I knew that I would need to add rib features to the 3D printed design to make up for the reduced material stiffness of PLA. Also, the "toe grab" features are a little larger for the same reason. 

Next as a quick check to ensure the ribs and sides were thick enough, I simulated a 450 lb downward force on the front "toe catch" section of the part. The simulation shows high stress that approaches the the tensile strength of PLA near the bottom inside corner of the ribs. I think my interpretation of the simulation results was conservative. The final print was much stronger that I anticipated. 

It took almost 10 hours to 3D print with 60% infill. I haven't installed in on a door yet but I did jump up and down on it a few times. I think there is opportunity to reduce the amount of material and still maintain all the functionality. The 60% infill is was overkill from a structural standpoint. A reduction in infill percentage will greatly reduce print time as well.

Discussions

Bertrand Girin wrote 05/01/2020 at 21:20 point

Hi John -- thank you for sharing your door opener. It gave me inspiration and I made a a variation of your model to pull a door and its latch at the same time: https://www.thingiverse.com/thing:4329328

Cheers!

Bertrand

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