Abstract: Apparatus is provided for use attached to a pipe string in a well drilling, service or servicing operation to create a signal in a fluid stream flowing in the pipe string and in material of the pipe string in response to indications of down hole sensors. The signal created consists of brief pulses created down hole and detectable at the earth surface as pressure changes in fluid flowing in the pipe string. Alternately, periodic bursts of higher frequency stress variations in the pipe string walls are transmitted as pulses. The repetition rate of the pulses varies over a preselected range as the down hole sensor output changes over a preselected range. The transmitter, which may be lowered and recovered through the pipe string bore, derives its power from the fluid pressure differential used to create pressure pulses. The pulse repetition rate variation dictated by a sensor output is controlled without taking energy from the sensor.

Abstract: Method and apparatus to lift the rotor of an earth borehole downhole drilling motor with a resilient force that exceeds the rotor weight so that starting of the motor is more certain due to reduced drag on primary thrust bearings. Additionally the apparatus may be used to reduce imbalanced axial loads on rotor primary thrust bearings.

Abstract: A clutch is provided to grip a body having a smooth cylindrical surface such that if the body moves relative to the clutch it is urged to do so with a predetermined relationship between the axial movement and the rotational movement. By rotating the clutch relative to the cylindrical body, the body is urged to move in a direction of its cylindrical axis. Similarly, if the clutch is moved axially relative to the cylindrical body, the body is urged to rotate. The clutch contains rolling elements and performs much as the conventional anti-friction circulating ball lead screw found on automotive steering gear devices but no spiral groove is needed on the cylindrical body. In addition to the obvious advantages of dispensing with the spiral groove on the cylindrical body, the structure can readily be adapted to one-way clutching action. Alternately, the clutch is provided with means to selectively permit over-running in either, neither or both directions of axial and rotary motion of the cylindrical body.

Abstract: A device attached to a pipe string extending from the earth surface to subsurface locations, primarily for earth boring activities to transmit information from the subsurface location to the earth surface. The readings of subsurface sensors are converted to a message comprising a combination of pressure pulses in fluid in the pipe string and brief stress changes in the wall material of the pipe string detectable in the pipe string at the earth surface, the combination identifiable as representing at least part of the message and series of pulses collectively representing the content of the message being transmitted.

Abstract: A drilling assembly is equipped with apparatus that includes a device that periodically changes the resistance to the flow of drilling fluid through the drill pipe to create pressure pulses that can be detected at the earth surface and a sensor for controlling the pulse orienting device in response to the orientation of the drilling assembly relative to a preselected orientation relative to earth.

Abstract: A combination of means to detect rotation of a pipe string and means to detect flow of fluid through a pipe string is utilized to cause down hole apparatus to carry out preferred actions if the sequence of rotation rate change and flow rate change is of one character, other activities being carried out if different sequences occur. Alternately, a choice of several actions to be taken by down hole apparatus may be elected by sustaining a flow condition while rotational conditions are manipulated at the earth surface.

Abstract: A roller clutch is provided that is capable of transmitting rotational forces between a first and second machine member. The first member is a cylindrical member such as a shaft, having a smooth outer surface. The second member includes a housing through which the shaft extends. A plurality of rollers are located between the housing and the shaft to transmit rotational forces between the shaft and housing while allowing the shaft to move axially relative to the housing.