Gripper assembly and lock/release method for a coiled tubing injector

Abstract

A gripper assembly for a coiled tubing injector, each assembly of a plurality of assemblies having a carrier adapted for mounting to the injector drive and a gripper block releasably connected to the carrier using a locking mechanism. In an embodiment a locking tab extending from one of the gripper block and carrier engages a slot of the other of the carrier or block. A locking shaft extends through the assembly to engage the locking tab and releaseably lock the block to the carrier. The locking shaft is rotatable between a locking position to engage the locking tab to prevent release from the slot and a release position to release the locking tab from the slot. The shaft is biased to the locking position.

The embodiments of the invention for which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A gripper assembly of a plurality of gripper assemblies driven by a coiled tubing injector, each gripper assembly comprising:
 a carrier driven by the coiled tubing injector, the carrier having a first locking part;   a gripper block having a second locking part; and   a locking shaft for releasable connection of the second locking part of the gripper block to the first locking part of the carrier, the locking shaft operable between a release position and a locking position,   wherein, upon actuation of the locking shaft to the locking position the locking shaft engages both the first locking part and the second locking part for connecting the gripper block and carrier and upon actuation of the locking shaft to the release position, the gripper block is released from carrier.   
     
     
         2 . The gripper assembly of  claim 1 , wherein the carrier has a front mounting surface and the gripping block has a back surface,
 the first locking part comprising locking slot in the front mounting surface and the carrier further supports the locking shaft aligned with the locking slot; and   the second locking part comprising a locking tab projecting rearwardly from the back surface,   wherein actuation of the locking shaft further comprises insertion of the locking tab into the locking slot and whereby the locking shaft engages the locking tab, retaining the locking tab to the carrier.   
     
     
         3 . The gripper assembly of  claim 2 , wherein the locking tab is inserted into the locking slot when the back surface of the gripping block seats against the front mounting surface of the carrier. 
     
     
         4 . The gripper assembly of  claim 2 , wherein the locking shaft extends parallel to and adjacent the locking slot and the locking tab has a locking profile formed therealong, in the locking position with the locking tab inserted into the locking slot, the locking shaft engages the locking profile for interfering with removal of the locking tab from the locking slot. 
     
     
         5 . The gripper assembly of  claim 2 , wherein the injector and gripping block have a coiled tubing inline axis, the locking slot and locking tab extending generally transverse to the inline axis. 
     
     
         6 . The gripper assembly of  claim 5 , wherein the locking tab and locking slot transfer inline forces therebetween. 
     
     
         7 . The gripper assembly of  claim 6 , further comprising:
 a positioning slot in the front mounting surface; and   a positioning tab projecting rearwardly from the back surface, the positioning slot and tab spaced from the locking slot and tab,   wherein the positioning tab is inserted into the positioning slot for transfer of inline forces therebetween.   
     
     
         8 . The gripper assembly of  claim 2 , wherein
 the locking shaft engages a locking profile of the locking tab;   the locking profile forms locking lip in along the locking tab; and   the locking shaft is positioned between the locking lip and the carrier's front mounting surface for retaining the gripper block to the carrier.   
     
     
         9 . The gripper assembly of  claim 8 , wherein the locking tab is an elongated body having a concave locking surface in the locking profile corresponding to a cylindrical locking shaft. 
     
     
         10 . The gripper assembly of  claim 8 , wherein
 the locking shaft is cylindrical, having a diameter and a chorded portion and a non-chorded locking portion formed therealong, a length of the chorded portion being at least as long as the locking tab;   the locking shaft resides within the locking profile and is rotatable between the locking and release position wherein upon rotating actuation of the locking shaft
 to the locking position the non-chorded locking portion is engaged with the locking tab; and 
 to the release position, the chorded portion is aligned with the locking tab for passing the locking lip thereby for releasing the locking tab from the carrier. 
   
     
     
         11 . The gripper assembly of  claim 10  wherein the chorded portion is located intermediate along the locking shaft. 
     
     
         12 . The gripper assembly of  claim 8 , further comprising a transverse shaft bore through the carrier for rotatably supporting the locking shaft therein and for positioning a locking shaft axis parallel thereto wherein the locking shaft partially overlaps the locking profile. 
     
     
         13 . The gripper assembly of  claim 1 , wherein the locking shaft is rotationally biased to the locking position. 
     
     
         14 . The gripper assembly of  claim 13 , further comprising a rotational actuating handle extending laterally from the locking shaft. 
     
     
         15 . The gripper assembly of  claim 14 , further comprising a handle groove in the front mounting surface of the carrier, the handle groove being in communication with the shaft for connection of the handle to the shaft therethrough. 
     
     
         16 . The gripper assembly of  claim 14  wherein the locking shaft is actuated from the locking to the release position by rotation along an angle between about 45 to about 90 degrees. 
     
     
         17 . The gripper assembly of  claim 9  wherein:
 the locking shaft is supported in a locking hole extending through the carrier, further comprising: 
 the locking shaft has a control end and retaining end, 
 the shaft's retaining end having an upset and a flat chorded edge formed thereon; 
 the locking hole has a counterbore for receiving the retaining end, the counterbore having a flat edge encroaching on the counterbore and corresponding to the flat chorded edge of the retaining end; 
 when retaining end's flat chorded edge is angularly aligned with the counterbore's flat edge, the locking shaft can shift axially to the locking position, engaging the flat chorded edge with the flat edge. 
 
     
     
         18 . The gripper assembly of  claim 17  wherein
 the control end of the locking shaft is biased to retain the retaining end axially in the carrier with the retaining end's flat chorded portion engaged with the counterbore's flat edge in the locking position. 
 
     
     
         19 . The gripper assembly of  claim 18  wherein
 the locking shaft is actuable to the released position by overcoming the biasing to temporarily disengage the retainer end flat edge from the counterbore's flat edge so as to enable rotation of the locking shaft. 
 
     
     
         20 . The gripper assembly of  claim 1 , wherein each carrier is supported upon an endless chain of the coiled tubing injector. 
     
     
         21 . A coiled tubing injector comprises:
 a pair of opposing endless chains;   a plurality of gripper assemblies driven by the pair of endless chain for running coiled tubing in or out of a well; wherein   each gripper assembly comprises:
 a carrier having a first locking part; 
 a gripper block having a second locking part; and 
 a locking shaft for releasable connection of the second locking part of the gripper block to the first locking part of the carrier, the locking shaft operable between a release position and a locking position, 
   wherein, upon actuation of the locking shaft to the locking position the locking shaft engages both the first locking part and the second locking part for connecting the gripper block and carrier and upon actuation of the locking shaft to the release position, the gripper block is released from carrier.   
     
     
         22 . A method for releaseably locking a gripper block to a carrier of a gripper assembly driven by a coiled tubing injector comprising:
 coupling a first locking part of one of the carrier and block and a second locking part of the other of the block and carrier;   locating a locking shaft between the first and second locking parts; and   actuating the locking shaft between a locking position and a release position, by
 rotating the locking shaft to the locking position to engage both of the first and second locking parts for connecting the gripper block and the carrier; 
 rotating the locking shaft to the release position to disengage the first locking part from the second locking parts for releasing the gripper block from the carrier. 
   
     
     
         23 . The method of  claim 22  wherein:
 the coupling of the first locking part and the second locking part of the other further comprises inserting a locking tab into a locking slot; 
 the locating of the locking shaft further comprises locating the locking shaft between the locking tab and locking slot; and 
 the actuating the locking shaft further comprises rotating the locking shaft to engage a non-chorded portion of the locking shaft with the locking tab in the locking position and rotating the locking shaft to align a chorded portion of the shaft with the with the locking tab in the release position. 
 
     
     
         24 . The method of  claim 22  wherein
 the rotating of the locking shaft to the release position further comprises overcoming a biasing of the locking shaft to the locking position.