Abstract: A rocket motor is provided with a self-actuated nozzle throat control mechanism. The motor includes a casing that forms a combustion chamber and houses propellant. An exhaust nozzle extends from the motor casing and is fluidly coupled to the combustion chamber. A pintle assembly is provided to vary the throat area of the nozzle. The pintle assembly includes a pintle and a support member. The pintle is coupled to the support member for movement from a first position to a second position where the pintle extends farther into the throat than when in the first position. A locking member secures the pintle to the support member in the first position when the pressure in the combustion chamber is in a first range and releases the pintle from the support member when the pressure in the combustion chamber changes to a value in another range. With this construction, a multistep pintle, which moves in response to change in combustion chamber pressure, can be constructed without complex control instrumentation.

Abstract: Improved cutter elements for drill bits of the type having two to four conical-shaped cutters mounted in a supporting body for rotation about their respective axes with their apices inclined downwardly-inwardly toward the axis of rotation of the body; the cutter elements are spaced apart from one another both axially and circumferentially of the substantially conical exterior of each conical-shaped cutter and, usually, disposed in spaced circumferential rows, each cutter element including a pair of interacting chisel or wedge-shaped teeth intersecting each other--preferably at their medial portions in perpendicular relationship--coextensive from crest to root and having their respective crests extending approximately radially of the axis of rotation of said cutter and generally circumferentially of said cutter axis; the circumferentially--oriented teeth have coextensive cutting edges at their ends and are adapted to cut through ridges created in the formation by the radially-oriented teeth and laterally displ