Re: [CAD_CAM_EDM_DRO] Z axis on the knee, how practical????

"Ian W. Wright" wrote:

> Air assist has been mentioned a couple of times but how practical are other
> methods of knee counterbalancing? I'm thinking of gas struts (because I saw
> a guy selling some new ones at a boot sale for 25 pence each - how do you
> determine the working strength of such things?) or weights and lines over a
> pulley.

Gas struts (maybe salvaged from cars, or better, overstock on new replacement
units) are basically the same as the air assist cylinders, except they don't need a
compressor. You need a scale and a press, or pulleys, or some similar scheme
to find the supplied force from the gas struts (called gas springs in the non-auto
industry in the US). Some of them are even marked with the force.

Be careful with these things, if the attachment ever gets loose, they can be deadly.
Someone mentioned quite a few years ago in R.C.M. that his wife was killed
by one when they were rear-ended, and the strut hit her in the back of the head.

Jon