The document describes the limitations of manually cleaning a blackboard and proposes a solution. The current method exposes cleaners to chalk dust which can cause respiratory issues. It also takes a long time and may leave stains. The proposed solution is a blackboard cleaning machine that moves a large vertical bar across the surface. This allows cleaners to avoid chalk dust and drastically reduces cleaning time by using a larger surface area. Possible modifications to the design include breaking up the cleaning bar into smaller pads that can individually lift off the surface to clean particular areas.

2. Content
I. Limitations of current method

3. Limitations of current method
1.1 Description of current method.
1.2 Hazards.
1.3 Limitation.

4. 1.1 Description of current method
Wipe small cleaning cloth
across the surface of the
blackboard.

5. 1.2 Hazards
Chalk dust
 Formula: CaCO3
 Physical attributes:
non-combustible,
odorless, white powder

6. 1.2 Hazards
Effects on animals:
Causes moderate to
severe irritation in
contact with tissues

7. 1.2 Hazards
Effects on human
Eyes nose Mucous membrane Respiratory system

8. 1.2 Hazards
Sneeze Inflamation Dry skin

9. 1.2 Hazards
With a near distance like this, cleaner has a high risk of falling ill with the
forementioned diseases

10. 1.3 Limitations

11. After
Before

12. Content
I. Limitations of current method
II. Solution

13. II. Solution
2.1 Theory To solve these problems
2.2 Concept
2.3 Limitations and possible modifications

14. 2.1 Theory To solve these problems
 Allow the cleaner to stay away from the board’s proximity,
effectively reduce the risks from chalk dust
 Increase the cleaning surface to reduce the amount of time and
work required to clean the board
 Optimize the quality of cleaning process, removing chalk dust
more effectively

15. 2.1 Theory To solve these problems

16. 2.1 Theory To solve these problems

17. 2.1 Theory To solve these problems
Avoid reduce exposure
to chalk dust

18. 2.2 Concept
2.2.1 Summary
2.2.2 Components
2.2.3 Working mechanism

19. • Cleaning the blackboard by moving
a large vertical bar across the
surface
2.2.1 Summary

20. 2.2.1 Summary
Blackboard cleaning
machine

21. • Stationary parts: vertical cylinder, horizontal
cylinder, pipe, upper rail, lower rail
• Moving parts: vertical piston, horizontal piston,
wheel, cleaning pad, connecting rod
2.2.2 Components

22. 2.2.3 Working mechanism
• As the vertical piston is pushed/pulled, the pressure in
the vertical cylinder will increase/decrease

23. 2.2.1 Working mechanism
• As the vertical piston is pushed/pulled, the pressure in
the vertical cylinder will increase/decrease
• The pressure change, combined with the non-
compressibility of the liquid inside, leads to the
displacement of liquid in the horizontal cylinder, moving
the horizontal piston accordingly

24. 2.2.1 Working mechanism
• As the vertical piston is pushed/pulled, the pressure in
the vertical cylinder will increase/decrease
• The pressure change, combined with the non-
compressibility of the liquid inside, leads to the
displacement of liquid in the horizontal cylinder, moving
the horizontal piston accordingly
• The cleaning pad, which is hard-connected to the end of
the horizontal piston by the connecting rod, sweeps
across the board and clean it in one go

25. 2.3 How it solves the problem of the old model
Dust?
Standing aside while operating
helps avoiding/reducing
contact with chalk dust.

26. 2.3 How it solves the problem of the old model
Time-consuming?
Larger contact surface and straight trajectory
drastically reduce the amount of time
required to clean the board.

27. 2.3 How it solves the problem of the old model
Visible stains?
without the repeated motion,
chalk dust is completely
swept away.

28. 2.3 Limitations and possible modifications
• The inability to clean a particular area
within the surface
Limitations

29. 2.2.1 Summary
March 25th 2014
Blackboard cleaning
machine
2.3 Limitations and possible modifications

30. 2.3 Limitations and possible modifications
• Vertically:
Separate the cleaning bar into multiple
adjacent cleaning pad.
• Horizontally:
Use a mechanism to make it possible to lift
each smaller cleaning pad off the surface.
Possible modifications

31. 2.2.1 Summary
March 25th 2014
Blackboard cleaning
machine
2.3 Limitations and possible modifications

32. 2.3 Limitations and possible modifications
•Your suggestions?
Limitations

33. Content
I. Limitations of current method
II. Solution