RGB Trap Pedal

UPDATE

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24-Oct-2023

I was able to get a print made where the pedal actually worked with TPU. I increased my perimeter lines to 4 lines and kept the Concentric infill. This allowed me to get plenty of air to the trap and get the doors to fully open and close. Unfortunately, this only worked for about 5 cycles. The lip at the base of the depression between the body and cap eventually gave out and stopped sealing.

If you are going to try to use this for a functional replacement, I would suggest something more flexible, like nylon. Due to the abuse this thing will ultimately be taking, some kind of casting with a silicone-based material may be the only way to reproduce this part faithfully.

Since I recreated this from an intact part, most (if not all) draft angles are intact.

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This is the Trap Pedal off the 1989 Kenner, The Real Ghostbusters, Ghost Trap. The part is the blue rubber part at the end of the yellow hose attached to the Ghost Trap.

I have modeled this off an existing, intact, Trap Pedal. This will allow you to print off a replacement to restore the toy.

Design

The toy pedal is made of 4 pieces (not including the hose):

1. Pedal Body (Rubber) - Main body
2. Pedal Seal (Rubber) - Large ring on the bottom of the pedal, likely there for manufacturing purposes
3. Pedal Cap (Hard Plastic) - Cap that plugs the air hole in the middle of the seal
4. Pedal Nipple (Hard Plastic) - Nipple seals the air port on the front of the pedal and increases air pressure to the pump assembly

Body Models

There are 4 models here for the trap pedal body:

1. Solid Model - Entire body is one piece
2. Filled Model - Body is solid but there is a depression in the base for the cap and seal (for looks)
3. Hollow Model - Model is hollowed out with a custom support pillar that can be removed after the print
4. Hollow Model (Unsupported) - Model is hollowed out without any custom supports

Configurations

1. Solid Model + Nipple
2. Filled Model + Nipple + Cap
3. Hollow Model + Nipple + Cap + Seal
4. Hollow Model (Unsupported) + Nipple + Cap + Seal

Getting the Pedal to Work

I have printed off a bunch of different models with TPU and have not got one to work yet. I may have my layers too thin (allowing air to escape) or some of the geometry just may not be friendly to TPU. 

My best attempt was with the Solid Model. I printed it with an 8% Archimedean chord infill and an 8% concentric infill. This created air chambers while supporting the body enough to let it hold its shape. The chords seemed to do the best.

I was able to use a drill bit to pop a hole to the center and insert the tube. I was able to get the doors on the trap to lift halfway with this printing style. I may try to put artificial infill into one of the hollowed out models with a proper air channel going down the middle, or hope someone with a little more talent than myself can modify it to work. 

Archimedean Chords

Concentric