Quote:
Originally Posted by Al Skierkiewicz
B,
There is nothing that prevents you from using two cylinders in series to obtain a three position mechanism. Apply air to one for the middle position and both for the fully extended.
|
If you make these cylinders of two different lengths, you would have four positions - both rectracted, short one extended, long one extended, both extended.
Stopping a cylinder in mid-stroke is fairly straightforward by using a 3-position solenoid valve. Center position is all ports blocked, so the cylinder is pseudo-locked in position, although with some spongyness. With the right position feedback, programming, and flow controls, you could move to any variable position.