The original McKibben type pneumatic muscle can contract like muscles. We can also make an extensible McKibben muscle with same materials. A difference is using a braided sleeve with shorten state.
- Expandable braided cable sleeving (adaptive size from 6mm – 1/4″ to 13mm – 1/2″)
MacMaster-Carr, Expandable Polyester Sleeving, 9284K2
- Soft Latex rubber tubing (outer diameter: 6mm – 1/4″, inner diameter: 4mm – 5/32″)
McMaster-Carr, Super-Soft Latex Rubber Semi-Clear Tubing, 5234K962
- Barbed tube fittings
- Cable ties (zip ties) (width: 2.5mm)
Tools and Equipments
- Metal rod (diameter: 6mm, length: about 150mm)
- Air tube (outer diameter: 3.2mm – 1/8″, inner diameter: 2mm – 5/64″)
SMC, Polyurethane Tubing, TIUB01
- Cable tie gun (optional)
Cut the braided sleeve in the three times the length of the desired muscle length, for example 160mm (=80m x 2). Insert a metal rod into the braided sleeve. Tie up the end of the rod and sleeve together with a cable tie. Push the sleeve along the rod until no more shortening. Then tie up the other end of the sleeve.
2Bake the sleeving
Bake in an oven at 120°C (248°F) for 20 minutes to fix the shorten state.
3Prepare tube and sleeving
Put marks with tapes on the shortened sleeve with rod in the desired length, for example 80mm. Release the sleeve from the rod and cut the sleeve according to the marks.
Cut the rubber tube in the same length.
Insert the barbed plug into the end of rubber tube.
Insert the rubber tube into the braided sleeve. Tie up the end of the tube and sleeve together with a cable tie over the barbed plug. Tighten the cable tie to prevent air from leaking. Cut off the excess strap of the cable tie.
Insert the barbed connector into the other end of the rubber tube.
Tie up the end of tube and sleeve together with a cable tie over the barbed connector. Tighten the tie to prevent the tubes from slipping off. Cut off the excess strap of the cable tie.
Connect the air tube and syringe to inflate the rubber tube and contract the artificial muscle.
Bon Appétit! (but don’t eat)