US Patent 7857042 Coiled tubing injector head

An improved coiled tubing injector head, comprising a plurality of powered chain loops, each having one practically straight side adjacent to the other chain loop(s) and biased against a tubing running in-between all the loops so as to grip the tubing and allow its transit into and out of a well. The chain loops are assembled from multifunctional links which both transmit drive and also form carriers for replaceable gripper blocks or are the carriers and gripper blocks combined, without need of a roller link chain or chains in addition to the multifunctional links. Three or more chain loops are provided, and the chain loops are driven by electric motors.