Multiple blow percussion drill assembly with rapid field mainten

Offshore platforms

Oil well jar

One-piece drill bit with improved gage design

Optional up-blow, down-blow jar tool

Overburden drilling apparatus having a down-the-hole hammer...

Percussion boring machine for destructive replacement of buried

Percussion boring tool

Percussion drill string assembly

Percussion-rotary drilling tool

Percussive down-the-hole hammer and a drill bit therefor

Percussive down-the-hole hammer and a piston and drill bit...

Percussive down-the-hole hammer for rock drilling, a top sub...

Percussive down-the-hole hammer for rock drilling, and a...

Percussive drilling apparatus

Percussive drilling apparatus

Pile handing methods

Pile with a foot

Pilot-valve-controlled percussion drilling tool

Pipe delivery system