With recentlty enhanced stabilisation features, The Foremost Floating Cushion Sub has been designed specifically to fit all mid to large blast hole rotary drills designed to drill soft to medium hard rock formations. When mounted into the drive spindle of the gear box it will provide a minimum of two and one half inches of free travel between the top of the drill string and the rotary drive. The extended travel capacity built into the cushion sub enables the drill operators to quickly and easily make-up and breakout connections on the drill pipe with minimal thread damage. When the rotary drive is lowered to pick up on the threads of the drill pipe, the piston component in the cushion sub will move up into the housing of the sub when the threads come in contact which will considerably lessen the impact not only on the threads of the drill pipe but also the bearings and gears retained within the rotary drive.

The unique configuration of the housing assembly will not only provide direct drive forces from the rotary drive to the drill string but due to its design also absorb torsional vibration from the rotary bit or DTH hammer assembly through the use of polymers incorporated in the drive system. Whether using pull-down or holdback methods of drilling, urethane cushions located on both the top and bottom ends of the piston stroke as well as some hydraulic dampening from within the housing cavity, the shock and vibration from the rock face will be greatly reduced.