Annular bit for the drilling a foundation, and a method for detaching an annular bit for drilling a foundation from a sunken tube

摘要

the invention relates to a required (1) to drill a workshop. the required (1) is a means to solve the intractable internal connection between the required (1) and a pipe (2).the invention concerns also a method to solve a required (1) to drill a workshop of a pipe (2) in abgeteuftem condition, whereby a connection between the required (1) and a pipe (2) solved in-house.