Mock Test (Practice question)

A design agency has designed a cartoon character to encourage students to wear goggles when using machines. A picture of the suggested character would be given out to you in the classroom by your teacher. The agency has developed a character called 'Safe Ed'. The design company intends to design a device that moves Ed's head up and down.

The suggested mechanism is contained within the box indicated in the handouts. When the handle is pressed, Ed's head moves upwards and then returns to its original position.

Complete the mechanism in Phun and submit your completed work in the shared folder. Name your file as:

209_TanAhSeng_SafeEd.phz

Pulley mechanical systems

What is a Pulley?

A pulley is a system consisting of usually a rotating wheel with a curved rim which is mounted on a hook or base for stability. A rope, belt, or chain can move along the wheel's rim to change the direction of a pulling force. Examples are a flagpole and a curtain rod.

A "single-fixed pulley" is a pulley that is attached to an object.

A "single-moveable pulley" is a pulley that is attached to a wire or rope so that it can move with the wire or rope.

A "single-fixed pulley" gains nothing in force, distance or speed, but it changes the direction of the force. A system of pulleys may be used to improve leverage in lifting weights, thereby reducing the force

required to move an object.

Engineers use pulleys in all sorts of applications. Here's your mechanical challenge for the day:

1. Design a pulley system that uses two pulleys to lift up a soda bottle vertically over a distance of 2 metres. Use your sketchbooks to sketch your ideas.
2. Draw a plan for using four pulleys instead to lift your soda bottle, and answer the following questions:

• Do you expect the force you will have to apply to move the bottle will be reduced? By how much?
• Do you think that adding ten more pulleys would make a difference? Why, or why not?
• Do you think the size of the pulley impacts how much force is needed to lift the bottle? Why, or why not?
• Do you think the smoothness of the rope or twine pulley impacts how much force is needed to lift the bottle? Why, or why not?
• Can you think of examples of three machines that incorporate pulley systems?
• Can you think of engineering problems that were solved through the use of a pulley or a pulley system?
• Can you find any examples of pulleys in your school, home, or community?

Using cams for an Automaton...

Automata is the plural form of automaton, a self-operating machine.
Source: http://en.wikipedia.org/wiki/Automata_(disambiguation)

Your assignment for today is to create a story idea based on a design taken from an automaton. To know more about automata and the mechanisms involved, you can Google or YouTube for it, or refer to the link HERE. For some inspiration, you can refer to this SITE. For some examples, you can refer to this GALLERY.

Please suggest your designs of the automata on one of the following media: PHUN, SKETCHUP, PAPER-BASED (in the form of sketches), and name the file as:

205_AutomataDesign_TanAhSeng

Note: If you are using PHUN or SKETCHUP, please include a text file that explains your design/s further.

Gears & gear systems

For your next assignment:

Challenge 1: Design a gear system that would allow one to turn a driver gear, and be able to turn a set of 3 different gears with different speeds, but in the SAME direction as the driver gear. The gear speeds should be:

• Driver Gear: 100 rpm
• Driven Gear A: 200 rpm
• Driven Gear B: 40 rpm
• Driven Gear C: 250 rpm

Use Phun, and tracers or other relevant attachments to the various gear systems, to visually indicate the rotation of each of these driven gears.

Challenge 2 (More challenging): Design a gear system that allows its users to move an object of mass = 5kg over a LINEAR distance of 1 metre, using the least number of gears that you can! You can show for both vertical and horizontal linear motions.

Submit your soft copies of your files (or take a screenshot/video screenshot of your designs), and submit them to the SUBMIT folder using the following 2 file names:

• GearsPhun1_209_TanAhSeng
• GearsPhun2_209_TanAhSeng

Basic Mechanisms, Levers and Linkages

From the lesson presentations done, answer the following 2 questions using Phun.

Question 1

Question 2

 Rename both your files as:

• ToyElephantPhun_209_TanAhSeng
• ToyBirdPhun_209_TanAhSeng

Introduction to Mechanisms...

As part of the requirements of the toy design project, your team would have to consider the inclusion of Simple Mechanisms, Simple Electronics and/or Structures into your designs. As a start, today's lesson would cover a basic introduction to simple mechanisms. We would be covering these 4 basic areas of mechanisms, and they are:

1. Levers
2. Cams
3. Pulleys
4. Gears

The class would be divided into 4 groups to uncover some of the content on the above 4 sub-groups. More instructions would be made known during lesson time.

For each of the group formed to tackle the above, these would be your roles:

• Team Leader (1 person): To lead the team in tackling the assigned mechanisms sub-group and assist in the presentation
• Recorder (2 persons): To be responsible in collating and recording observations by the other team members, and to ensure coherence in the delivery of the presented materials
• Researcher (3 persons): To be the key persons in charge conducting research for the assigned sub-topic on Mechanisms. They would also ensure that all media forms recorded are sourced appropriately and attributed correctly

You can use the following 2 sites as your initial references:

• Technology Student
• Systems & Control