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Figure 2: Back View of Exoskeleton
The last addition to Prototype 2 was the detailed and thought-out BOM and assembly plan. In the previous design, the linkages were secured with nut and screws. This was adequate for an initial prototype, but added far too much friction to allow for a small motor to actuate all of the mechanisms. In this SolidWorks design, every component of the mechanism was detailed before assembly. In particular, thought was placed with regards to friction reduction. As a result, the current SolidWorks model details predefined holes, shafts, bearings, retaining rings, and screws to ensure an easy assembly and relatively frictionless mechanism. The interface between bearings, shafts, retaining rings, and linkages are shown in Figure 3. In general, the shafts are press-fit into a linkage and the inside diameter of the bearing. The bearing is press fit into the other shaft. A spacer is placed over the shaft and between both linkages to ensure no contact. Finally, retaining rings are placed on both sides to ensure that the shaft and both linkages are secured axially.
Figure 3: Transparent View of Bearing Interface