Non threaded drill pipe connection

A threadless connection for coupling segments of drill pipe longitudinally end to end, comprising:

• a pin end on each drill pipe segment having a groove for receiving therein a locking ring;
• a box end on each drill pipe segment having a groove for receiving the locking ring therein when the pin end is inserted into the box end;
• a compressible locking ring having an uncompressed diameter selected to at least partially engage the groove in the pin end and the box end when the pin end is inserted into the box end, the locking ring configured to enable sufficient change in diameter to disengage from the groove in either the pin end or the box end, the locking ring comprising at least one of a piezoelectric and a magnetic material;
• and
• a metal seal ring disposed in the box end prior to insertion of the pin end therein, the metal seal ring expandable by insertion of the pin end to substantially eliminate wobble;
• wherein the metal seal ring is concave on a radially outside edge thereof;
• wherein the metal seal ring is convex on a radially inside edge thereof;
• wherein the metal seal ring comprises an essentially planar sealing surface on each of a top end and a bottom end thereof, said planar sealing surfaces extending from said inside edge to said outside edge;
• wherein the metal seal ring is disposed in a shoulder formed in the terminal end of the box end;
• further comprising corresponding torque transmitting features on both the pin end and the box end to enable transmission of torque through the connection in either rotational direction;
• and
• wherein the torque transmitting features extend longitudinally along the respective pin and box ends, in a direction parallel to at least a portion of the central axis of the pin and box ends.