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BUILDING THE HOME-MADE AIR MUSCLE
by christophe-masclet@noos.fr
Do you know LEGO used to sell some spare parts? The 48mm pneumatic cylinder is an example.

Wanting to built a pneumatic 6-legged walker">

Engine | Development | Primer | Supplies | Constructopedia | Control |Compressors | Tester | Build | Bibliography | Miscell
 

BUILDING THE HOME-MADE AIR MUSCLE
by christophe-masclet@noos.fr
Do you know LEGO used to sell some spare parts? The 48mm pneumatic cylinder is an example.

Wanting to built a pneumatic 6-legged walker, I was very worried about this subject : I had not enough pneumatic cylinders. So I decided to build my own ones with plastic tubes but it takes a way I wasn’t expecting for.

Surfing all day long on the net I was searching information about pneumatic and robotic when I discovered the « McKibben’s Air-muscle ». I was surprised by the air-muscle simplicity, 2 days later I’ve build my first prototype.

What you need :

Only cheap parts are needed to build the air muscle:

 

1. A balloon (the same children blow up for their birthday). Search for long ones in «everything for feast »shop -10 for 1 US$

2. Heat-retractable sheath (electric shop) -1meter for 2 US$

3. Aquarium tube or similar -1 meter for 0.5 US$

4. Plastic collar - (electric shop) 20 for 1US$

5. A 4 mm diameter LEGO tube (same in R.I.S box) or similar

6. Braided sheath, I don’t know exactly its price but you should find it in electric, audio or computer shop.

7. Modeling plastic is very helpful to build the LEGO compatible piece.
 


Modeling plastic
Note on braided sheath

Item 6, braided sheath, is called "expandable sleeving" in the US. A web search will give you many companies which sell this material. Many companies do not sell expandable sleeving in small quantities, but you can order a small quantity for less than US$10.00 (about 4 meters) from http://www.cableorganizer.com. 

Thanks to Joe Burney for the update.
 
WORK

1. First cut the balloon size you want and adjust it on the aquarium tube, add glue.
2. Place the heat-retractable sheath on the tube/balloon connection and heat it.

3. Then you can place the braided sheath and 2 collars.
4. It’s time to use the modeling plastic.
Use LEGO bricks to build a mould. Finalise the piece with knife.

5. On other side you could make a loop with braided sheath, place 2 collars.
Add the 4mm LEGO tube that will perfectly fit the aquarium tube and the pneumatic LEGO tube.
Don’ t expect to build a perfect air-muscle the first time. Test different possibilities.

Also by Christophe:  Home-made One-way Valve

 

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