Design Review 3 Group 28 – Rodrigo Bergamasco, Pranay Sharma, Eli Zauner
		Mechanism Our mechanism, “Old Faithful”, was built out of aluminum to raise and lower a cylindrical weight two inches. In order to accomplish this task, our team focused on constructing a strong base and a long truss to support our servo and its rotating arm. In order to minimize the moment that the weight of the cylinder applies on the servo, we decided to extend the long truss out near the weight, and then place the servo and its lever at a close proximity to the cylindrical weight. By capitalizing on this design we were able to avoid the necessity of a counterweight. Since the weight limit for this project was 20 ounces, we first built a bare skeleton of our mechanism’s structure and then dedicated the remaining weight available to the addition of support members. This resulted in a very simple, but strong structure that could withstand the forces of lifting a one pound weight.
Features	“Old Faithful” has several interesting features that aided in its success. Our project: · Does not use a counterweight · Weighs 20 oz. · Capitalizes on a very simple design · Uses a short servo lever arm that can “catch” the cylindrical weight
Calculations	We decided to use a 3-inch lever arm for our final design because it kept the theoretical torque required from the servo below the maximum of 72oz-in and provided us with a maximum lift that was significantly greater than the 2-inch minimum we needed to achieve. The calculations for these requirements are shown below: Since the lever arm starts off at an angle of exactly 45° below the horizontal and rotates through an angle of 90°, the arm ends up at an angle of 45° above the horizontal. Using these measured angles, we can show how our design is capable of a total lift of 4.24 inches: Although our design is theoretically capable of lifting the 1lb weight 4.24 inches vertically, this value is not achievable in reality because the calculations do not take into account the bending of our structure due to the additional load of the 1lb weight. However, a value close to the calculated value of 4.24 inches is achievable and therefore our design exceeded the theoretical requirements needed for this project.
Photographs