Abstract: A washing tool (24) attached to the lower end of a pipe string (18) includes a mandrel (28) between upper and lower subs (30, 32). The mandrel (28) has opposed spaced end sections (54 56) connected with an intermediate section (58). Each end section (54, 56) has a fluid inflatable elastomeric packer (64) thereon inflatable at a relatively low fluid pressure, and intermediate section (58) has a leaf spring (86) over a port (84) which is opened by outward movement of the leaf spring (86) at a second higher predetermined fluid pressure within the pipe string (18).

Abstract: In a borer head for drilling boreholes in rock structures and including a drive shaft connected to a drive of a drilling machine, a central shaft coupled to the drive shaft, and a tool holder with cutters driven by a planetary gearing connected to the central shaft, supporting elements, engageable with a cylindrical wall of the borehole being drilled, are provided. The supporting elements are operatively connected to the central shaft and also to the tool holder so that the tool holder is driven into a slow rotation about the central shaft.