Gravity is always working against us, to pull that instrument down off your thumb.
I wanted to see if I could create a device that would prevent this from happening, yet still allow for freedom of movement while playing.
My earliest prototypes were "sling" or "hammock" style devices. They worked at preventing slippage.
These did hold the violin up at the correct height, and the supple nature of the sling conformed well to the contour of the neck. I thought I was on to something!
That excitement was short lived.
It only took a few minutes of playing to realize that to support the weight of the instrument with a sling like device required the thumb to pull back against the tension. This utilized muscles that are not up to the task, and it became uncomfortable in a very short period of time.
It was back to the drawing board!