The difficult and often time consuming task of rigging power transmission lines has been made easier in recent years by the use of helicopters which raise the transmission cables and pull them between the transmission towers. A number of U.S. patents have been granted for equipment which allow aerial stringing of cables to be done and, of these, the following patents disclose the type of equipment which presently is available; U.S. Pat. No. 4,006,884 issued on Feb. 8, 1977 to Donald A. Lederhos, U.S. Pat. No. 3,868,089 issued on Feb. 25, 1975 to Keith E. Lindsey; U.S. Pat. No. 4,129,287 issued on Dec. 12, 1978 to Keity E. Lindsey; U.S. Pat. No. 3,586,256 issued on June 22, 1971 to Bertie William Wellman.
Only the patent granted to Lederhos addresses itself to the problem of placing a transmission cable on a portion of a tower which cannot be entered from above or from the side of the tower. This particular patent discloses a cable-catching device which must be secured to the towers and a disengageable connector employing a rather complex interconnecting parts. The operation of such a device demands a high degree of skill and a great deal of patience on the part of a helicopter pilot and these as well as other disadvantages inherent in the device may explain why it has not found greater acceptance.