You may be wondering what a “Bowden Cable” is and why you would want one. A Bowden cable was purportedly invented to be used for bicycle brakes and is still used for this as well as for shifters. A wire is put inside of a semi-rigid tube allowing pulling forces to be transmitted over a distance. Besides bicycle use, these can be used for automation and animatronics.
While working on a larger project (more on this later), I came up with the idea to use 5/32 air line with fishing line (or very small cord) to make my own cables. Although not perfected by any means, here are the results:
As you can see from this video, the “jaws” can be moved up and down as well as opened and closed. When fully controlled and with something more rigid than the low-test fishing line that I had lying around, both actions should be able to operate independently. The key to this is that because of the airline “jacket” and fitting, the force on the jaws is applied directly where the fishing line exits it’s support. So the lower line pulls the jaws up and down as a unit, where the upper line simply pulls the jaws shut.
This setup is more of a proof-of concept than anything, but the plan is to link this with a more rigid support on the bottom of the airlines (it’s my hands in the video) and some servos. It should make a pretty nice “automated puppet platform” or maybe some sort of “reach extender.” We’ll see where this goes…
I also found this video on Youtube that was made for a plane apparently. This really illustrates a strength of these cables in that they are curved in a nice wide arc and still seem to work very well. You definitely don’t have the freedom to bend things to your liking with most linkages.