1. Chair Design
8th grade project
Written by
Sony Gala

2. Problem
Students will use the engineering design process to design and build a cardboard chair. The teacher will sit in the chair for at least 90 seconds.
Final products:
Engineering design portfolio (need not be typed)
¼ scale chair
Cardboard chair

3. Requirements Students will work in groups of four
Assign each member a duty
Member Name - Design Engineer
Member Name - Document handler
Member Name - Researcher
Member Name - Material handler
Decide on a group name – relate to the project (ex: CardChairs R Us)

4. Requirements: Constraints: 2 sheets of cardboard ~ 7’ x 3.5’
Chair must have a back
Seat of chair must be at least 18” off the floor.
Constraints:
Students will not use any form of adhesives to build the cardboard chair
No glue, tape, staples, nails etc.

6. Center of Gravity
A structure remains standing only if its center of gravity is directly over the perimeter of its base.
Center of Gravity

7. Loads and Joints 1. What is a load? What is the load on a chair?
What is a static load?
What is the static load on a chair?
What is a dynamic load?
What is the dynamic load on a chair?
What are joints?
How can one take care of weak links?
Why do most chairs fail?
10. What does orthotropic mean?
11. Give an example of orthotropic material.
12. How would you cut cardboard?

8. Orthotropic Material What does orthotropic mean?
Give an example of orthotropic material.
How would you cut cardboard?

9. Research Go to the Cardboard chairs websites from Ms. Gala’s website.
Watch video
Read about cardboard chair designs
Google image search on cardboard chairs

10. Alternative Solutions
Each student in a group sketches three chairs you may have at home or school.
ex: dining chair, sofa chair, office chair, deck chair, lawn chair, etc.
Think about form, comfort, looks etc.
Sketch ideas for cardboard chair.
Use graph paper

11. (copy definition) Orthographic Drawing – sketches made in two dimensional views. Objects can be seen from the front, top, side and back.

12. Measure your classroom chair (inches)
Fill in the chart provided. This will give you an idea about chair dimensions.
Standard Classroom chair
Length
Height
Width
Back of chair
Chair seat
Legs or base

13. Plan on measurements for cardboard chair (inches) Fill in chart.
Convert all measurements to ¼ scale. Divide each number by 4. Write ¼ scale number in parenthesis.
Your Cardboard Chair
Length
Height
Width
Back of chair
Chair seat
Legs or base

14. Final Design Use graph paper, ruler and pencil
Orthographic drawings – front view, side view and top view
Show measurements
Scale 4” – 1”
18 inches

15. ¼ scale chairs Refer to the orthographic drawing
Use one sheet of poster paper
Draw and cut out patterns to build a ¼ scale chair.
Remember no adhesives or attachements of any type

16. Full Size Chairs First draw patterns on the cardboard sheets
Minimize use of material
Use gloves, base cardboard mats and box cutters
Score cardboard to make sharp folds
Cut slots that are straight and parallel to make tight joints