Machine for cutting a cylindrical specimen of rocket propellant

Abstract

A machine provides in situ cutting of a specimen of elastomeric propellant rom a rocket motor wherein an undetached plug is formed by an annular opening cut through the motor casing and into the propellant. The machine has a length of resilient wire secured at its ends to a rod for forming a loop mounted on the rod. The rod is inserted into the opening at one side of the plug with the loop around the plug. The rod is then rotated to wind the wire onto the rod so as to contract the loop and sever the plug. A tray is pivotally mounted on the rod between the rod and the plug with the wire passing through slots in the tray. The tray is inserted into the opening beside the specimen so as to prevent engagement of the rod with the specimen during cutting and to receive the detached specimen for removal from the motor. The rod and tray extend from an assembly having an air motor rotating the rod through reduction gearing and through an overrunning clutch which drives in the loop contracting direction. This assembly is mounted so that a load cell measures the torque being applied to sever the plug. When the specimen is severed, the air motor is reversed allowing the resilient energy stored in the wire to dissipate as the wire unwinds. When the wire is fully unwound, the overrunning clutch prevents winding the wire in the reverse direction.