*The basic frame consists of gear case and cardan joint. The distance of hole will be easy to control and not to be restricted by gears.
The set up time is thus saved and it is mostly free of dead angles. It is very suitable for working of round holes and is the easiest to
operate among the adjustable type. To ensure the lifetime of the cardan joint, the moving range should be confined within 15 degrees,
which means within a distance of 30mm to the vertical status.
(We will design the structure of gear case, that is, the position of the boring hole as much as possible according to the coordinate of