| 摘要 |
The present invention relates to a cutting tool for widening the diameter of a borehole and method thereof, where the cutting tool comprises a housing defining an internal chamber in which a moveable activation element is arranged. The activation element is moved in an axial direction and is connected to one or more cutting blocks via a mechanical coupling. The mechanical coupling transfers the axial movement of the action element into a radial movement of the cutting blocks. As the differential pres- sure across the tool drops below the biasing spring force, the activation element is pushed back towards its starting position which in turn causes the cutting blocks to move back into the housing. The cutting blocks extend into one or more cavities formed in the activation element, thereby increasing the travel-to-expansion ratio. The cutting blocks can be replaced by stabilizer blades which are used to stabilize the drill- ing in the expanded borehole. |
