Show-and-tell: Linkage Pictures
Announcements
Next week is our final class period before final project presentations! It will be a workshop. You MUST bring something physical, either part or all of your project, to work on in class. If you need more space you can go out in the shop but report to class 1st. I encourage you to share your project with your classmates, elicit feedback, and get some work done! I will speak with each of you individually.
Final Project Guidelines:
- Each presentation will be 10-15 minutes including questioning
- It must move! It doesn't have to be electromechanical, it can be hand actuated.
- There is more emphasis this time on a working final project, so please leave yourself time for design iterations and mechanical fix-ups. This part of every mechanical design process and brings the system full circle. Also, keep in mind that if you don't work at ITP, your project must survive the trip to ITP.
- Volunteers for 1st day?
Linkages in the real world of design: frog can crusher
Cams and followers
Cabaret Mechanical Movement pg 53
Basic Machines pgs 6-6, 11-12
Cam videos
A cam is basically any eccentric or non-circular shape that converts rotary motion into some other type of motion
Types of cams:
- Edge/disk/peripheral cams (most common) - circles with lobes: snail cam
- Cylindrical/barrel/drum cam
- Face/radial/plate cam
The part that the cam moves is called a follower. It can be
Flying pig cams
Automatons
- Early kinetic sculptures that explored movement through gears, springs, linkages, etc
- Powered by winding, water, gravity
- Music boxes and mechanical (wind up and pendulum) clocks were precursors to more toy-like machines
Leonardo's robot 1495
Jacques de Vaucanson
Jaquet-Droz
- 1774 Writer - arguably most perfect ever built video
Maillardet - 19th century Swiss mechanician, created an automaton capable of drawing four pictures and writing three poems Maillardet's Automaton
Japan adopted automata during the Edo period (1603-1867); they were known as Karakuri
Cabaret Mechanical Theatre
Flying Pig
Optical Toys
Ben Hopson: Investigation of Motion in Product Design
Fluids
- Fluids can be liquids OR gases, they take the shape of the container they're in
- Because of this, fluids exert pressure in all directions P=F/A (hydrostatic pressure)
- Pressure depends on the depth and weight of the fluid
- Pressure - depth x density
- Viscosity=stress/strain rate
- LOW=water, MEDIUM=syrup, HIGH=silly putty
- Newtonian Fluid - flows like water (linear viscosity)
- Non-Newtonian - viscosity changes, see walking on "water"
Hydraulics vs. Pneumatics
- Hydraulics - fluid driven (not compressible)
- Normally operated at high pressures (~1000psi)
- Backhoes and industrial machinery
- Heavy lifting jacks
- Pneumatics - gas driven (air is compressible)
- Pneumatics normally used at lower pressures (~100psi)
- Dentistry
- Used where electric motors dangerous (underground mines)
- Pneumatic drills, jackhammers - just need a compressor
- Cheap options:
- Air brush kits
- Bike tire pumps
- Car tire pumps
- Portable table top compressors
Design on a Dime
Robot Builder's Sourcebook
