CSM -- Manufacturing and Assembly

The materials used for our project include the following:

As was previously discussed, the initial prototypes were largely constructed out of 1/8" thick plywood that was laser cut for ease of construction. A 1:4 model wheelchair was 3D printed and used in all the developed prototypes while the wheels were also laser cut from plywood. Aluminum rotary shafts were used to pin the plywood links, and nuts and bolts were used to fasten the linkages and assemble the mechanism. 

For our final prototype, we decided to machine the links out of aluminum due to its machinability. The pushbar and guide slot components were cut out of a 1/4" thick aluminum plate with the water jet machine due to their unconventional geometries. While this was quick and straightforward, the resulting hole and slot tolerances were poor for press and slip fits, respectively. This required much sanding and finishing with files, sandpaper, and power drills for the desired fits. The cranks were constructed using the vertical mill from 1/4" thick aluminum bars, and the rotary shaft grooves and lengths were machined on the metal lathe. Due to the nature of our project, much finishing work with benchwork tools was necessary to achieve relatively unhindered motion between the linkage components. Bearings were used to facilitate smooth rotation of links, and retention rings fixed mutual link distances on the shafts. Nuts and bolts from the MakerSpace were used to create the final mechanism assembly.