Helicopter threadable stringing block assembly for power conductors

Abstract From the Canadian patent

A converter yoke and stringing block assembly adapted to be threaded with a helicopter-dispensed conductor hauling line dropped thereonto from either side of a power line. The yoke sub-assembly can be used in lieu of a conventional stringing block yoke thereby to convert a manually threaded block for threading by helicopter, or the features of the invention can be embodied in a stringing block as initially manufactured. The separate yoke brackets are spaced apart to provide an open-ended threading passage and the exit end of the latter is initially extended by dislodgeable guide members shiftable to their normal retracted positions automatically as the advance end of the comductor running …