Abstract: A closed loop control system for a core drilling mechanism automatically controls the penetration rate, the weight on the drill bit, and the torque load applied to the drill string, and maintains all three at or below preselected maximum values. The closed loop control system incorporates a controller that receives sensed information and generates corresponding control signals to control the penetration rate and thus the weight on the drill bit and the torque load through a servo valve in a hydraulic drive circuit. One or more sensors are provided to sense the penetration rate of the drill bit, and are coupled with the controller. Similarly, sensors are provided to determine the weight on the drill bit and the torque load applied to the drill string.

Abstract: An oil field assembly for gathering data about or producing an oil well having a self regulating assembly for free movement by gravity or the differential pressure of fluids in the tubing string of a well from the surface of a well or to predetermined down hole positions for collecting data and or producing a well while freely moving between the surface of the well and predetermined positions comprising a self regulating traveling piston for free movement by gravity and or the differential pressure of the fluids of a well from the surface of a well and to predetermined positions for collecting data about a well between the surface and predetermined downhole positions, and having instrumentation connected to the traveling piston for gathering data about the well, and a landing housing located at the surface of a well for receiving the traveling piston, and a receiving station at the bottom of the tubing string for releasably receiving the traveling piston.