I have looked around and found very little about this concept. Basicly it's a vertical column mounted to the floor and wall with thrust bearings. There would be linear rail attached vertically to the column with a horizontal arm coming off. The column would be rotated in combination with moving the carriage in and out on the horizontal beam to achieve x and y movement. The whole horizontal arm will be raised and lowered for z travel. Have any of you seen anything like this. What do you think of it?
You're probably not finding much because it is not a very practical approach. Unless you keep the system extremely small, rotational inertia imposed on the main column by the swinging mass out on the jib would be too difficult to control. By the time you resolve the flexural and inertial issues of a larger system you will just wind up with something heavy and slow.
What Rick 2.0 said. Supporting somethin like a router on a single ended arm would be quite unstable. I've seen a plasma cutter similar to this, but with no Z, just X and Y. And, a plasma cutter has very low weight and inertia. MG
