Design Breif
Gantt Chart
Decision Matrix
Brainstorming List
Pre-Sketch
Final Sketch
Building Process, Testing Results, and Modifications
It was basically trial and error the whole time. We had the general idea in our head and then went on to implicate it by simply seeing what would work. We first thought to have the whole machine geared for speed, and then before testing it I changed some gears to provide torque. This slowed the weight down greatly so we were quick to go back to the old idea which almost worked flawlessly except for the fact that the weight either wasn't heavy enough, or wasn't being dropped from high enough, so we simply added more weight to the structure we would drop on the stapler and finally got our machine to work properly. As far as results go, the first test was a failiure because the weight was too slow, the second test, after fixing the gears, got varied results because the weight was too light and did not have enough inertia, and the third and final test showed a 100% success rate after we simply added more to the object we dropped. If I could go back I would probably find some way to make the crank easier to turn since it is a little difficult at the moment.
Final Design
Final Calculations
We found our machine consisted of five machines; two wheel and axles, one sprocket, one gear set, and one pulley. The IMA of our first wheel and axle was was 1 to 1, the IMA of our sprocket was 3/5, the IMA of our gear set was 3/7, the IMA of our second wheel and axle was 1/2, and finally, the IMA of our pulley was 1. This all multiplies to get the entire machine's IMA, 0.129. Our overall AMA was 0.279 after calculation, and the overall efficiency turned out to be 55.8%
Conclusion Questions
- For which mechanism was it the easiest to determine the mechanical advantage or drive ratio? Why was it the easiest? I found the pulley and the first wheel and axle to be the easiest because the pulley simply takes you counting strands and the wheel was the same diameter as the axle so they simply equaled one. Basically, both of them took no calculations.
- For which mechanism was it the most difficult to determine the mechanical advantage or drive ratio? Why was it the most difficult? I thought that the second wheel and axle was the most difficult because we had to measure their diameters ourselves since we couldn't find it online.
- What are your estimates the input and output force values of your compound machine? How did you arrive at your estimated values? We found our estimated input force to be 4.84lbs by using the force scale and attaching it to a chain that was connected to the crank before finally pulling it and recording what the computer told us the force was. Then we found the weight's force to be 1.35lbs by hooking the scale onto it and recording what the computer read the weight was.
- What modifications could you make to your compound machine to make it more mechanically efficient? Any modification other than to the crank(the first wheel and axle) would cause the machine to not function properly, so the only one I could think of is increasing the diameter of the crank/wheel you use to activate the entire device. This would mean it would take less force to run the machine because a big wheel is turning a smaller axle, instead of it being 1 to 1 like we currently have it.