Prof. J. Walter - Informationstechnik, Mikrocomputertechnik, Digitale Medien Mechanical
Hochschule Karlsruhe Logo Microcontroller Technology
Intelligent Crutch

4.8 Mechanical

The original inner 19 mm crutch tube is cut and extended by riveting a 22 mm aluminium tube onto it. This is done to provide more space inside the tube for accomodation of the electronic PCB in the final prototype. The 22 mm is closed on the bottom by a 3D-printed cap, made from PLA (polylactic acid). This part will be made from metal on a turning lathe for the final prototype.

test setup lower tube cut  test setup lower tube
Figure 4.8.1: CAD-Model of the linear bearing and lower assembly

All CAD-files as Creo Parametric files:

The 22 mm tube serves as one half of a linear bearing. The other moving half is made from another anodized aluminium tube with 25 mm outside diameter. Mounted on this tube is a 3D-printed foot made from TPU (thermoplastic polyurethane), a flexible type of plastic. In case of the test setup a 3D-printed box is mounted as well on this tube to house all electronics. A small opening on the side gives acccess to a USB micro port for charging the lithium battery and programming the ESP32 microcontroller. Both subassemblies are attached via one bolt. This one sits in a circular whole on the outer tube but in an elongated whole on the inner tube. This allows for axial movement of a few mm.

Test Setup lower Tube  Test Setup lower

electronics box  linear bearing

Test Setup Assembly
Figure 4.8.2: Assembly of the intelligent crutch

  With Support of Prof. J. Walter Summer Semester 2021