Project 1.1.6 Compound Machine
Design Problem:
Our Compound machine must lift a weight of approximately 8 ounces a vertical distance of 6 inches in less than 3 minutes.
Objectives:
Students should understand how the elements of design can affect mechanical advantage. At the end of the project we should know how simple machines can work together to accomplish a task. Studen. Students should be able to compare the efficiency of different simple machines in a working situation. Finally, we will experience the capabilities of VEX components for future projects.
Design Constraints:
The force applied to work the compound machine should be applied by a single human input. The final design must also include a minimum of three different types of mechanisms. Two simple machines and a third mechanism; a gear system, a pulley and belt system, or a sprocket and chain system. Each required mechanism must have a mechanical advantage of greater than one and the final machine must have an overall mechanical advantage greater than one.
Brain Storm:
In my idea, there is a sprocket and chain system, a block and tackle system, and a second class lever. The sprocket and chain system is the input and applies its output force to the block and tackle system. The block and tackle has a fixed pulley attached the top of a box structure, and a movable pulley attached to the lever. The movable pulley pulls up on the second class lever and the lever lifts the weight.
Our Compound machine must lift a weight of approximately 8 ounces a vertical distance of 6 inches in less than 3 minutes.
Objectives:
Students should understand how the elements of design can affect mechanical advantage. At the end of the project we should know how simple machines can work together to accomplish a task. Studen. Students should be able to compare the efficiency of different simple machines in a working situation. Finally, we will experience the capabilities of VEX components for future projects.
Design Constraints:
The force applied to work the compound machine should be applied by a single human input. The final design must also include a minimum of three different types of mechanisms. Two simple machines and a third mechanism; a gear system, a pulley and belt system, or a sprocket and chain system. Each required mechanism must have a mechanical advantage of greater than one and the final machine must have an overall mechanical advantage greater than one.
Brain Storm:
In my idea, there is a sprocket and chain system, a block and tackle system, and a second class lever. The sprocket and chain system is the input and applies its output force to the block and tackle system. The block and tackle has a fixed pulley attached the top of a box structure, and a movable pulley attached to the lever. The movable pulley pulls up on the second class lever and the lever lifts the weight.
Final Design Proposal:
Our group used a decision matrix to decide whose design we should build. Each of us rated all of five categories (simplicity, reusability, build time, precision, and run time) for each of the compound machines. After adding all of the ratings together, we would build whichever design had the highest score. Luke’s design had the highest score so we chose his. Luke’s design has a chain and sprocket system, 2 wheel and axles, and a pulley system. The effort force is applied to the wheel and axle, which then transfers its force onto the chain and sprocket system through a plate. The chain and sprocket system transfers the force back through the plate and into the second wheel and axle system. The second wheel and axle system then rolls up the pulley system and the weight.
Our group used a decision matrix to decide whose design we should build. Each of us rated all of five categories (simplicity, reusability, build time, precision, and run time) for each of the compound machines. After adding all of the ratings together, we would build whichever design had the highest score. Luke’s design had the highest score so we chose his. Luke’s design has a chain and sprocket system, 2 wheel and axles, and a pulley system. The effort force is applied to the wheel and axle, which then transfers its force onto the chain and sprocket system through a plate. The chain and sprocket system transfers the force back through the plate and into the second wheel and axle system. The second wheel and axle system then rolls up the pulley system and the weight.
Final Design Presentation:
Our machine functioned smoothly in the final presentation. We were able to move our weight 6 inches in under 3 minutes. The compact design made the machine easy to operate and understand, which yielded good results.
Each system had an IMA of over one: the first wheel and axle system had an IMA of 2; the chain and sprocket system had an IMA of 1.5; the second wheel and axle system had an IMA of 4.3; the pulley system had an IMA of 2. The overall IMA of the system was 25.7 and the overall AMA was 8.3. After calculating the AMA and IMA the overall system efficiency is estimated at 32%.
Team Evaluation:
Lucas Gretta followed the group norms and was essential to the team’s success. Luke came up with the design for an extremely functional compound machine and worked hard throughout the entire project. Luke built the structure and did many of the calculations.
Madeline Farkus helped the group by suggesting ideas and helping build. She did her share of the work by following the group norms, doing calculations, and having quality ideas and builds on the machine.
Michael Friedmann followed the group norms and was also an important member of the team. Michael did his share of the work by scanning the documents, building, and doing calculations.
I was an important member of my team because I did a lot of building in the group for the structure of the machine. I followed the group norms and provided quality presentations and builds as well as calculations.
Post Mortem:
A.
It was easiest to determine the mechanical advantage for the pulley because all we had to do was count the number of load bearing strands.
B.
It was most difficult to determine the mechanical advantage of the second wheel and axle because we had to measure the diameter with calipers, and it was not a very rounded of number
C.
To make our compound machine more efficient I would change the structure that it was built on to avoid extra friction and collisions. I would also change the positioning of all the parts by switching sides. This would make it easier to put in the input and would make the machine look better from the front.
Our machine functioned smoothly in the final presentation. We were able to move our weight 6 inches in under 3 minutes. The compact design made the machine easy to operate and understand, which yielded good results.
Each system had an IMA of over one: the first wheel and axle system had an IMA of 2; the chain and sprocket system had an IMA of 1.5; the second wheel and axle system had an IMA of 4.3; the pulley system had an IMA of 2. The overall IMA of the system was 25.7 and the overall AMA was 8.3. After calculating the AMA and IMA the overall system efficiency is estimated at 32%.
Team Evaluation:
Lucas Gretta followed the group norms and was essential to the team’s success. Luke came up with the design for an extremely functional compound machine and worked hard throughout the entire project. Luke built the structure and did many of the calculations.
Madeline Farkus helped the group by suggesting ideas and helping build. She did her share of the work by following the group norms, doing calculations, and having quality ideas and builds on the machine.
Michael Friedmann followed the group norms and was also an important member of the team. Michael did his share of the work by scanning the documents, building, and doing calculations.
I was an important member of my team because I did a lot of building in the group for the structure of the machine. I followed the group norms and provided quality presentations and builds as well as calculations.
Post Mortem:
A.
It was easiest to determine the mechanical advantage for the pulley because all we had to do was count the number of load bearing strands.
B.
It was most difficult to determine the mechanical advantage of the second wheel and axle because we had to measure the diameter with calipers, and it was not a very rounded of number
C.
To make our compound machine more efficient I would change the structure that it was built on to avoid extra friction and collisions. I would also change the positioning of all the parts by switching sides. This would make it easier to put in the input and would make the machine look better from the front.