Recumbent trike accessory smartphone cradle.

The HP Velotechnik Scorpion recumbent trike doesn't have many options for mounting accessories. The vertical handlebars (with twist shifters) are open at the top of the tube and perfect for receiving an expanding accessory post. Other recumbent trikes, without thumb shifters, may also be compatible.

Leveraging my prior design for a T-Bar accessory post I created a standardized post assembly and interchangeable phone trays that slide onto the post assembly and affix with the tightening screw.

The 6mm x 110mm bolts used are for bunk beds, and the securing nut fits inside the tightening wedge. I printed both parts on an OPXL2H using input shaper and .32 structural. You need to print the handle upside down to better manage supports. I had to apply a enforced support as the auto-generated support was not durable enough. For the wedge use supports and a brim.

Bolts: https://www.amazon.com/dp/B07C61Q3P2

Simply slide the tray onto the post and place the securing nut inside the expanding wedge and then slide the assembly into the expanding fins on the handle. Thread the bolt down the handle and tighten slightly to secure the assembly. You can then slide the whole assembly into the handlebar tube and tighten securely.

The first tray is for an iPhone 15 Pro Max with Apple faux leather case (82mm wide). There are small retaining posts inside the tray to secure the phone/case. You might need to file them slightly depending upon filament shrinkage. In the future I will include several other tray sizes, ymmv.