USA As Represented by Secretary of the Navy

Norman G Zweirzchowski

Robert Lynn Gerber

Herbert P Richter

Larry R Boyer

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.

Machine for cutting a cylindrical specimen of rocket propellant

A machine performs in situ excision of a specimen of tough and highly elac solid propellant from a fin of the propellant disposed within a cavity extending from the nozzle opening of a rocket motor. The machine is mounted at the opening and has a rod extended into and moved generally axially of the cavity by an actuator assembly. A knife is mounted at one side of the rod end within the chamber. A mounting assembly supports the actuator assembly on the rocket motor and provides selective positioning of the actuator assembly axially of the cavity, of the angle of rod movement to the cavity axis, and of the knife position rotationally within the cavity. The actuator assembly has a guide received in the mounting assembly. The rod extends through the guide which prevents rotation of the rod while guiding it axially. From the guide, the rod extends successively to and through an air cylinder and a hydraulic dampening cylinder to a rod end bearing an adjustable stop for selecting the axial movement of the rod. A valve selects the degree of hydraulic dampening. Preferably, the knife is stirrup-shaped with a cutting edge facing either direction axially of the rod, and the air cylinder is double acting. Cuts may be thus made by extending or retracting the rod with a force and rate selected by the pressure applied to the air cylinder and by the degree of hydraulic dampening.

Growing community of inventors

Ridgecrest, CA, United States of America

Norman G Zweirzchowski