Handle for car seat adjustment strap

This model has not undergone any safety testing and is provided for demonstration purposes only. Read and follow all instructions for your child's car seat. Contact the manufacturer of your car seat for guidance before adding any accessories. Do not use this with a child in the car seat unless specifically approved by your car seat manufacturer.

This handle attaches to the webbing loop on a car seat adjustment strap so that it's easier to tighten.

Design features

• Built for webbing that is 25mm wide.
• Screw goes into a “slider” piece that makes contact with the webbing, so it doesn't rub directly on it.

Hardware requirements

• One M3 socket head screw between 70mm and 80mm.
• Two M3 DIN 562 square thin nuts (see “Nut selection” below)
  • The distance between the nuts is calibrated for a standard 0.5 pitch.
  • If you are using a different thread and it doesn't fit, skip the far nut.

Printing

• Print the main handle piece in flex material for softness.
• Print the slider piece in a harder plastic for rigidity.
• Print each model as-oriented in the .stl file.
• Choose a material appropriate for your environment.
• No supports should be needed.

Installation

Nut insertion - for each nut

• Gently insert the nut into the rectangular opening on the handle.
• You can use a M3 screw to push it all the way in (it's going to stop halfway).
• You can push it out by inserting an M3 screw from the other end.
• Optionally, you can add a dab of glue from the rectangular insertion end to secure it in place permanently.

Attaching to webbing loop

• Feed the webbing through the small opening in the handle until the loop is fully through.
• Put the slider through the webbing loop.
• Pull the webbing back until it is stopped by the slider.
• Insert the M3 screw from the circular opening on the end of the handle, carefully pushing it through the slider, until you reach the nut.
• Tighten the screw carefully (stop once you meet a bit of resistance; this is tricky to feel with the handle printed in flex).

Safety notes

• This model has not undergone any safety testing and is provided for demonstration purposes only.
• Read and follow all instructions for your child's car seat.
• Contact the manufacturer of your car seat for guidance before adding any accessories.
• Do not use this with a child in the car seat unless specifically approved by your car seat manufacturer.

Other notes

• I've designed this with OpenSCAD in a parameterized way. If you'd like any modifications (e.g., the webbing width), please send me a message and I'll see what I can do.