Instructions on how to build part of the wheelchair lever arm in solidworks for this project:
Step 1: Sketch a Circle With Diameter 137mm and Extrude 25mm Upward Using "Extrude Boss"
Step 2: Sketch a 106mm and 120mm Diameter Circle on the Surface of the Cylinder and "Extrude Cut" Downward for 10mm
Step 3: Sketch a 106mm Diameter Circle on the Front Plane and "Extrude Cut" for 4mm Downward
Step 4: Sketch Three Circles of Diameters 92mm, 96mm, and 106mm on the Front Plane
Step 5: Create a Centerline Vertically From the Top of the Circle, Draw Half of a Tooth, and Use "Mirror Entities" to Mirror It Across the Centerline to Create a Tooth
Step 6: Use "Circular Pattern" to Copy the Tooth and Create 88 Identical Teeth Around the Inside of the Gear
Step 7: "Extrude Base" the Sketch by 4mm to Create the Gear Teeth
Step 8: Sketch a Circle With Diameter 48.76mm in the Center of the Front Plane and "Extrude Cut" Downward 4mm Into the Gear
Step 9: Sketch a Circle With Diameter 34.96mm at the Center of the Front Plane, "extrude Cut" All the Way Through the Gear
Step 10: Sketch Two Circles With Diameter 34.96mm and 35.76mm and "Extrude Base" the Space Between Them to Create a Barrier in the Center of the Gear
Step 11: Create the Spoke Pattern on the Back of the Annular Gear
Open up the wheel Solidworks file of the wheelchair in an assembly. Assemble the annular gear and wheel together using concentric mate, mating the inner circle of the gear to the cylindrical shape of the hub of the wheel. Be sure to face the gear side of the annular gear away from the wheel. Sketch on the flat side of the gear a circle just a little bigger than the hub. Exact dimensions are not required. Then sketch two sets of parallel lines from the outer edge of the gear using the spokes of the wheel as a reference. Be sure that the lines are big enough and angled in a way that the spokes lie inside the sketched lines. The sketched lines should resemble an isosceles triangle. Use circular pattern to create a total of 9 identical sketches. Re-adjust the position of the lines as needed to fit the spokes of the wheel.