US Patent 7441993 Making connections to pipes under pressure

Methods and apparatus for making connections to pipes and pressure vessels while they are under pressure employs a first drive mechanism for delivering a cutting tool to the pipe or vessel wall and a second separate drive mechanism for powering the movement of the cutting tool through the wall. The long linear travel associated with the transit of the cutter to the wall is divorced from the short cutter travel required to perform the actual cuffing operation. This allows the two long and short travel systems to be designed independently of one another, and engineering compromises between them can be avoided.