Gripper for coiled tubing injectors

A gripper assembly comprising:

• a carrier, said carrier having an upper surface with at least two channels;
• a gripping shoe positioned on said carrier;
• said gripping shoe having at least one downwardly extending leg, each leg carrying a tab and said gripping shoe has an upper surface configured to grip coiled tubing;
• wherein said downwardly extending leg and tab cooperate with said carrier to preclude lateral movement of said gripping shoe while permitting rotational movement of said gripping shoe on said carrier, wherein in the assembled configuration, said upper surface of said gripping shoe defines the central axis of said gripper;
• wherein in the assembled configuration, said inwardly projecting tabs cooperate with said carrier to retain said gripping shoe on said carrier.

A gripper assembly comprising:

• a carrier;
• said carrier having an upper surface, said upper surface having two recessed channels;
• a gripping shoe positioned on said carrier;
• said gripping shoe having two downwardly extending legs, each leg carrying a tab and said gripping shoe has an upper surface configured to grip coiled tubing;
• wherein said tabs cooperate with said carrier to preclude lateral and vertical movement of said gripping shoe while permitting rotational movement of said gripping shoe on said carrier, wherein in the assembled configuration, said upper surface of said gripping shoe defines the central axis of said gripper assembly;
• and,
• wherein in the assembled configuration, said tabs cooperate with said carrier to retain said gripping shoe on said carrier.

A method of assembling a coiled tubing gripper assembly comprising the steps of:

• securing a carrier to a coiled tubing injector chain, said coiled tubing injector chain defining a plane;
• positioning a gripping shoe over said carrier such that gripping shoe is in the plane of said coiled tubing injector tube, said gripping shoe has an upper concave surface configured to grip coiled tubing, the concave surface defining an axis;
• placing said gripping shoe on said carrier such that said axis is out of alignment with said plane of said chain;
• rotating said gripping shoe until the axis defined by said upper concave surface corresponds to the plane defined by said chain, thereby securing said gripping shoe to said carrier.

A method for replacing a coiled tubing injector gripping shoe in a coiled tubing injector assembly said injector assembly comprising a pair of parallel drive chains, each drive chain supporting a plurality of coiled tubing gripper assemblies wherein each assembly comprises a carrier and a gripping shoe, said drive chains defining a plane and said gripping shoe having an upper concave surface defining an axis such that said axis aligns with said plane when said gripping shoe is secured to said carrier, the method comprising the steps of:

• positioning a gripping assembly having the gripping shoe to be replaced on the back portion of a drive chain;
• rotating said gripping shoe thereby moving said upper concave surface out of alignment with said plane;
• lifting said gripping shoe off of said carrier within the plane defined by said parallel drive chains;
• positioning a replacement gripping shoe within the plane defined by said parallel drive chains with said upper concave surface out of alignment with said plane;
• placing said replacement gripping shoe on said carrier;
• rotating said gripping shoe until the axis defined by said upper concave surface aligns with the plane defined by said parallel drive chains.