Pipe connector with variable angle for directional drilling - where hydraulically actuated valve is used to restrict flow of drilling liq. while connector angle is changed

摘要

This is the fourth addn. to 7822063, the others being 7908803, 7908804, 8021890, all of which describe a pipe connector with a variable angle, used for directional drilling. The novelty in the present invention is the use of a valve which reduces the force of the drilling liq. while the angle of the pipe connector is being changed, but which does not affect the flow of the drilling liq. during normal drilling operation. The valve consists of two radially-opposed pistons located in a drill rod, and normally kept in a retracted position by spring pressure. But hydraulic fluid can be used to drive the two pistons inwards to restrict the dia. of the bore of a drill rod while the angle of the connector is altered.