Cable seal unit for earth-boring drill strings

A cable seal unit for coupling a cable to an earth-boring drill string, said unit comprising a cylindrical shell having an axially oriented hollow interior, said shell having opposed, coaxially aligned end portions, one of which is internally threaded and the other of which is externally threaded, for fitting said shell intermediate two adjacent pipe sections in a drill string so that the shell forms a substantially continuous assembly with the string, a wall of said shell having an aperture inclined at an acute angle to the shell axis, through which aperture a cable may pass from the interior to the exterior of the shell, sealing means for sealing the aperture around the cable, said shell having an external recess communicating with said aperture, and means adjacent said recess for securing to said shell a cable clamp which may surround said cable and be disposed in said recess;

• and wherein the interior end of the aperture is of smaller diameter than the remainder, thus defining a shoulder at the interface, said unit further comprising an annular packing seat positioned against said shoulder, and wherein said sealing means comprises a packing material which is compressed against the packing seat;
• and further including a cable clamp which is attachable to the shell wall by said securing means.