Coupling means for sewer rod

Claim 1

In combination: a. first and second cylindrical metal rod sections, a-1. each rod section having its end portions flattened and spread to form shoulders at the junction of the end portion with the cylindrical portion of said rod section; a-2. each rod section having its flattened end portion inclined downwardly and upwardly along the center axis of the rod section, the flattened end portion of the second rod section being inverted relative to the flattened end portion of the first rod section and interfitted therewith in overlapping manner; b. coupling means for connecting said interfitted rod sections axially together in overlapping manner for transmitting axial and torsional forces from one rod section to an adjacent rod section without substantial loss, said coupling means comprising: b-1. first, second and third coupler elements; b-2. said first coupler element having an externally threaded shank having an internal recess, said shank having shoulders at its inward end for bearing against said shoulders of said first rod section; b-3. said second coupler element being internally threaded at both ends, and adapted at one end to be screwed onto the shank of said first coupler element, said second coupler element having a center recess having a cross-sectional dimension corresponding to that of the flattened and spread end portions of said rod sections; b-4. said third coupler element having an externally threaded shank adapted to be screwed into the other end of said second coupler element, said shank having an internal shoulder for abutting against the shoulders of said second rod section.