Gripping jack system

The combination comprising a generally vertically extending tubular outer member, an inner support member extending upwardly through said outer member, and jacking mechanism for lifting said outer member relative to said inner member, said jacking mechanism comprising:

• a gripping unit extending about said inner member at a location above said tubular outer member and including a slip bowl structure, slips adapted to be cammed inwardly by said bowl structure to grip said inner member at a first diameter and thereby support the gripping unit from said inner member, and means for actuating said slips relative to said bowl structure between upper gripping positions and lower released positions;
• and
• power operated means supported by said gripping unit and connected to said tubular outer member for exertion of upward force thereagainst to jack said tubular member upwardly relative to the gripping unit and inner member;
• said tubular outer member extending upwardly to a location at which it can apply force to said slips in an upward grip tightening direction in response to upward movement of said tubular member relative to said inner member by said power operated means.

Jacking mechanism for lifting a generally vertically extending tubular outer member relative to an inner support member extending upwardly therethrough, comprising:

• a gripping unit adapted to extend about said inner member at a location above said tubular outer member and including a slip bowl structure, slips adapted to be cammed inwardly by said bowl structure to grip said inner member at a first diameter and thereby support the gripping unit from said inner member, and means for actuating said slips relative to said bowl structure between upper gripping positions and lower released positions;
• power operated means supported by said gripping unit and adapted to be connected to said tubular outer member for exertion of upward force thereagainst to jack said tubular member upwardly relative to the gripping unit and inner member;
• said jacking mechanism being open to extension of said tubular outer member upwardly, at a diameter greater than said first diameter, to a location at which said tubular outer member can apply force to said slips in an upward grip tightening direction in response to upward movement of said tubular member relative to the inner member by said power operated means;
• and
• a sleeve to be received about said members and having an internal diameter substantially greater than said first diameter at which said slips grip said inner member to allow extension of said tubular member upwardly radially between said sleeve and said inner member for tightening said slips.

Jacking mechanism for elevating a tubular outer member relative to an inner member extending upwardly therethrough, comprising:

• a first gripping unit to be received about said inner member at a location above said tubular outer member and including an upwardly tapering slip bowl structure, slips having gripping faces adapted to engage and grip said inner member at a first diameter and having upwardly tapering camming surfaces engageable with said bowl structure to cam the slips into gripping engagement with said inner member in response to application of downward force against said bowl structure, and means for actuating said slips relative to the slip bowl structure between upper gripping positions and lower released positions;
• a second gripping unit adapted to be received about said tubular outer member and including a downwardly tapering slip bowl structure, slips having gripping faces for engaging and gripping said tubular outer member at a second diameter greater than said first diameter and having downwardly tapering camming surfaces acting to urge the slips into tight gripping engagement with said tubular outer member in response to exertion of upward force against said slip bowl structure of the second gripping unit, and means for actuating said slips of the second gripping unit between lower gripping positions and upper retracted positions;
• power operated means for moving said second gripping unit upwardly relative to said first gripping unit to raise said tubular outer member relative to said inner member;
• said jacking mechanism being open to extension of said tubular outer member upwardly to a location at which said tubular outer member can apply upward force to said slips of the first gripping unit in a relation tightening the grip of said slips on said inner member in response to upward actuation of said tubular member by said power operated means;
• and
• a sleeve to be received about said outer tubular member at a location axially between said two gripping units and having an internal diameter great enough to pass said tubular member upwardly through the sleeve and to a position for exertion of upward grip tightening force against said slips of the first gripping unit.