Blog 6 (Practical 4)

Operating principles & Mechanism desgins

I learnt that in order for devices, apparatus and equipments to work, they require working principles that are either mechanical, electrical, chemical or magnetism. 

Exanples of these everyday devices are:

-Steam traps operate on the principle of gravity

-Brewing coffee involving the leaching of coffee solubles

-Air-lift pump works on the principle of buoyancy

Engineering mechanism

In chemistry, mechanism is the fundamental chemical processes involved in or responsible for an action, reaction or other natural phenomenon.

In engineering, on the other hand, mechanism refers to the combination of rigid or resistant bodies, formed and conncected so that they move with definite relative motions with respect to one another. In other words, it is something that transforms forces and movement into a desired set of output forces and movement.

Essential mechanisms found in functional prototypes

-Actuators

-Cams

-Gears

-Lever

-Ratchets

-Springs

Ping pong ball launcher

Our ping pong ball launcher used the actuator mechanism to function as the propulsion principle. Here is what we wrote for the CA2 report part 4.

Ping Pong Ball Launcher

Propulsion Principle  An actuator will pull a pointed plastic backwards, storing energy in the actuator in the form of compressed air. When it moves forward it converts the stored energy into motion, thus propelling the ping pong ball forward. One can fix how far the ball travels by supplying the actuator with different amounts of compressed air.  Ball Loading Gears can be used for ball loading. A single gear can be attached to the front of the magazine so that it constantly moves the ball forward to be supplied to the ping pong ball launcher. This is to ensure that the balls do not get stuck in the magazine.

Sketch The rubber flap prevents the ball from dropping out of the launcher. The rubber flap prevents the ball from dropping out of the launcher. The launcher can be reloaded automatically.

Practical 4

In Practical 4, we were tasked to design and make a marble run machine out of cardboard in 2.5 hours. However, we were given about 4 extra days before the practical to make small preparations before coming for the practical.

The requirements for the practical are the following:

-The cardboard structure must incoporate one manally operated mechanism.

-The structure must be able to keep a marble in continuous motion for at least 30 seconds.

-The structure should not be more than 100cm x 100cm x 100cm

-Structure should be made predominantly out of corrugated cardboard.

After creating the marble run machine, each group needed to do a show and tell covering the different joineries used, the mechanism employed to move the marble and to have a live demonstration of the marble run in action.

Before starting making our marble run machine, our group took a long time to brainstorm of possible ideas to include into our marble run machine. We wanted to do something different from other groups, hence this took a while. This is our rough sketch of what we tried to include in our marble run machine.

However, we soon changed our mind on making these types of marble run machine. Instead, we decided to make a pinball machine as the marble run machine.

My group used slot and tab and brass fastener as the cardboard joinery methods and lever and spring as the operating mechanism.

The spring was used to launch the marble into the pinball machine.

The lever was used as the manually operated mechanism to keep the marble moving in the machine

The brass fastener was used to make the lever where we stacked many layers of cardboard over one another to make the lever thicker.

The slot and tab was used to make some of the obstacles as well.

Finished product

Hero shot of finished product

Video of our marble run machine

Reflection

This practical was not easy. With the little amount of time we had and the expectations we had to meet to make the marble run machine, I am sure everyone felt a lot of pressure. Looking at other group's marble run machine ideas made this challenge slighlty daunting and on the day of the practical, there were only two of us and it may have made things a bit worse, however, I am glad we decided to press on and come up with a great idea that met the requirements. Looking at so many different marble run machines has also shown me the so many different ways that cardboard can be used and it really inspired me to become good at making things with cardboard one day too. Overall, this final practical has allowed me to use the knowledge I have learnt from the past few practicals and lessons and I felt that it was really useful.