Patent ID: 8701754

Claim:
A coiled tubing injector, comprising: a plurality of elongated gripper chains, each of which is comprised of continuous chain loop having mounted thereon a plurality of gripping elements, the plurality of gripper chains each having sections that are arranged to form between them a gripping zone for gripping tubing when placed between sections of the gripping chains, the gripping zone having a central axis aligned with the center axis of tubing passing through the gripping zone; a drive system coupled with at least one of the plurality of gripper chains; for each gripping chain in the plurality of gripping chains, at least one skate extending behind the sections of the gripping chains that form between them the gripping zone for causing gripping elements on the chain to apply to tubing, when passing through the gripping zone, a force normal to the surface of the tubing; wherein at least one of the at least one skate behind at least one of the plurality of gripper chains has formed thereon at least one strain relief region for dividing the gripping zone into a strain relief segment between two traction segments, the strain relief region reducing the amount of the force a gripping element applies when it moves into the strain relief segment as compared to what it applies when it is located within either of the two traction segments.