A TRACTOR FOR USE IN A BORE

摘要

A subsurface apparatus in the form of a tractor is adapted for travel throug h a bore containing a moving fluid stream. The tractor comprises a body, a dri ve arrangement for moving the body in a desired direction, a member mounted on the body and adapted to be driven by the moving fluid, and a conversion arrangement for converting movement of the member to drive for the drive arrangement. The drive arrangement may include a contactless magnetic coupli ng and a harmonic drive.