Toy OTF Switchblade (Double Action)

This is my improved toy OTF double action switchblade design. Double action means the blade ejects when the switch is pushed forward and retracts when the switch is pushed backwards with no manual reset required.

This design does not require any metal hardware like springs or screws and prints with minimal supports. Instead of springs to lock the blade this design uses printed latches to lock the blade in place. These latches pivot down when not in use meaning they are not under continuous tension. This is important because it allows the design to be made with PLA which permanently deforms under a continuous load. Instead of using screws the parts are pinned in place by 1.75mm filament.

To learn more about how this 3D printed mechanism works I suggest watching the animation and assembly video found below.

You can obtain a commercial license to sell prints of this here. Commercial seller tier club members have permission use this model for commercial purposes during active membership.

Printing

I suggest printing each part in the orientation show in the image below. I also suggest printing the tall parts with a brim. The only part that needs support is the bottom of the carriage (this support appears green in the image below).

Rubber bands

All the parts are printed except for the rubber bands. The number of rubber bands needed depends on the type of rubber bands used. I like to used two strong rubber bands linked here and two weak rubber bands linked here. You can also follow these links to find specifications about the dimensions of the rubber bands.

Assembly

To assemble the toy just follow the animation found below. I recommend applying a plastic lubricant to all moving parts.

Troubleshooting

If you have trouble getting the mechanism to work I suggest watching the assembly video. This is an uncut video showing the tricks I use to clean up my prints and troubleshoot the mechanism.