Rockwell International Corporation

Other

Electric Power Research Institute Incorporated

The United States of America As Represented by the Administrator of the

Iowa State University Research Foundation, Inc.

Robert B Thompson

George A Alers

Carmine F Vasile

Christopher M Fortunko

William E Peterson

Leigh R Burns, Jr

Samuel J Wormley

Paul K Davidson

Roger B Houston

Marion A Tennison

An improved gas piston system for the automatic loading of a rifle, especially a rifle of the M-16/AR-15 type. The system employs a barrel nut, or an adaptor to a barrel nut, that has been modified to secure one end of a gas piston system. The other end of the gas piston system, namely the piston rod, engages, either directly or indirectly, the key on a bolt carrier group. This configuration positions the gas piston system at a point starting near the barrel nut and extending to the bolt carrier group of the rifle, while a gas tube extends from the gas block to the gas piston system a point near the barrel nut.

Hybrid gas-piston rifle and barrel nut

An improved gas piston system for the automatic loading of a rifle, especially a rifle of the M-16/AR-15 type. The system employs a nut, or an adaptor to a barrel nut, that has been modified to secure one end of a gas piston system. The other end of the gas piston system, namely the piston rod, engages, either directly or indirectly, the key on a bolt carrier group. This configuration positions the gas piston system at a point starting near the barrel nut and extending to the bolt carrier group of the rifle, while a gas tube extends from the gas block to the gas piston system a point near the barrel nut.

A condom includes a condom tubular side wall having a first side wall end and a second side wall end, the tubular side wall being rolled outwardly and over itself from the second side wall end toward the first side wall end to form a side wall roll; a condom end wall sealingly joined to the tubular side wall at the first side wall end; and at least one strip of flexible material having a gripping tab end segment with a touch distinctive tactile surface on one side thereof, the at least one strip being wound within the side wall roll so that the gripping tab end segment and touch distinctive tactile surface of the at least one strip protrudes from the side wall roll. A method of assembling the condom includes the step of winding the at least one strip together with the tubular side wall outwardly and over the tubular side wall toward the side wall second end to form a side wall roll, so that the gripping tab end segment protrudes from the side wall roll. A method of applying the condom to a penis includes the steps of grasping the tab end segment, touching the touch distinctive tactile surface thereon, orienting the condom so that the tubular side wall roll is directed away from the user, placing the condom end wall against the distal end of the penis, and pulling the tab end segment laterally outwardly from the tubular side wall, so that the side wall roll unrolls over and advances longitudinally along the penis.

Wound tab condom and method of application

Apparatus and method for nondestructive evaluation of butt welds. The present invention in its broadest form includes an apparatus and method for detecting flaws in butt welds in steel sheets using horizontal shear ultrasonic waves generated on the surface thereof. Observation of reflected waves having amplitude greater than a chosen value signals the presence of significant flaw. To achieve this objective, the present apparatus detects only reflected horizontal shear waves; other modes are electronically removed using bandpass filters, since they occur at different frequencies. The invention may therefore be used in the presence of surface structures such as clamps and the like, and in the presence of surface nonuniformities in the vicinity of the weld, thereby permitting on-line flaw detection steel mill environment without interfering with the line output. The ultrasonic waves are generated and received by a pair of electromagnetic acoustical transducers having magnetic fields which are oriented 40-65 degrees from the direction of the transmitted and received waves.

Apparatus and method for nondestructive evaluation of butt welds

The system for field measurement of texture, stress and related material properties such as formability parameters using ultrasonic velocity measurements through crystalline plate or sheet. Electromagnetic acoustic transducers are utilized to generate, transmit, and receive ultrasonic bursts through the plate at different angular orientations with respect to the plane of the plate. Two of the transducers are driven in series when generating the ultrasonic bursts. Time measurements between transmission and reception of the bursts are precisely derived and converted into velocities. Information regarding stress, texture, and other related material properties such as formability parameters can be derived from these velocity measurements. The system is adjustable to be used for both ferrous and nonferrous crystalline plate. Alteration of the types of ultrasonic waves utilized, and the methods of generating the waves allows different properties such as texture and stress to be derived.

Means and method for ultrasonic measurement of material properties

Disclosed is an electromagnetic acoustic transducer for use with electrically conductive objects. The transducer includes an electromagnet for establishing a static magnetic field directed into the object in a first region and directed out of the object in a second region. A meander coil for inducing eddy currents in the object when an alternating current is applied to the coil includes a first serpentine printed circuit on a first side of a printed circuit board and a second serpentine printed circuit on a second side of the board. The source and the coil are so oriented that the vector product of the field and the eddy currents produces an instantaneous force field in the object which is periodically alternately oriented.

Electromagnetic acoustic transducer

An electromagnetic transducer for exciting selected modes of ultrasonic vibration in a tubular body. The transducer includes a plurality of rows of permanent magnets of alternating polarity with a coil provided about the magnets whereby a current is conducted through the magnetic fields. The rows of magnets are provided in carriers which are yieldably biased towards the inner surface of a tubular body during inspection.

Electromagnetic acoustic transducer for tube inspection

Disclosed is a method for determining the thickness of an object, including the steps of generating a higher order mode ultrasonic wave at a first location on the object, varying the frequency of the generated wave, and measuring, at a second location on the object, the minimum frequency at which the generated wave will propagate in the object. Where the ultrasonic wave generated is a horizontally polarized shear wave, the thickness t may be calculated from the relationship

Ultrasonic apparatus and method for measuring wall thickness

Disclosed is a method for evaluating the structural integrity of an object, including the steps of generating a lowest order horizontal shear wave in the object, detecting the wave after it has propagated through the object, time gating the detected signal to reject nonuseful portions, Fourier transforming the time response of the detected signal into a frequency dependent response, and predicting the structural integrity of the object from the characteristics of the frequency response.

Ultrasonic non-destructive evaluation technique for structures of

Disclosed is an electromagnetic acoustic transducer, including an electrical conductor adapted to carry an alternating current in a current plane, the current being conveyed by the conductor in uniformly spaced, parallel, and alternate directions at any instant, and a source of magnetic flux positioned to direct a static magnetic field parallel to the alternate directions, the transducer thereby being adapted to generate or detect a horizontally polarized shear wave in a ferromagnetic material. The transducer may be made unidirectional by adding a second electrical conductor adapted to carry a second alternating current 90.degree. out of phase with respect to the first alternating current in a second current plane substantially coplanar with the first current plane, the second current being carried by the second conductor at any instant in parallel and alternate directions spaced by the same uniform amount, the second conductor being parallel to but staggered from the first conductor by half of the uniform amount.

Ultrasonic shear wave transducer

Disclosed is a nondestructive test device for detecting a flaw proximate to a welded seam in a pipe, including an electromagnetic acoustic transmitting transducer for generating a horizontally polarized shear wave in the wall of the pipe, a high frequency generator operatively connected to the transmitting transducer for energizing the transducer, an electromagnetic acoustic receiving transducer for responding to a horizontally polarized shear wave within the wall, an amplifier operatively connected to the receiving transducer for boosting the response signal of the transducer, and an indicating instrument for receiving and displaying the amplified response signal. In the test method disclosed, a horizontally polarized shear wave is generated in the wall, the pipe is monitored to detect a reflected horizontally polarized shear wave, and a time-dependent representation of the amplitude of the reflected wave is displayed. The wave generating, monitoring, and displaying steps are repeated along a length of the pipe to provide a comprehesive flaw inspection of that length of the pipe. The times of arrival of the generated and reflected waves are correlated to determine the circumferential position of the flaw.

Nondestructive testing utilizing horizontally polarized shear waves

Disclosed is a method for generating an ultrasonic wave in a material, utilizing a transducer adapted to induce a higher than fundamental mode wave in the material and a signal generator adapted to drive the transducer at a frequency above the cutoff frequency below which the higher mode wave will not propagate. For a horizontal shear wave, optimal transducer efficiency is obtained by selecting a driven frequency between a minimum cutoff frequency f.sub.c =v.sub.s n/2t and an upper frequency sufficiently close to f.sub.c to drive the transducer with at least a preselected increase in efficiency.

Method and apparatus for efficiently generating elastic waves with a

Disclosed is an electromagnetic acoustic transducer for generating and detecting an elliptically polarized ultrasonic wave in an electrically conductive material. The transducer includes a row of uniformly sized, adjacent, alternately oriented permanent magnets, which establish a periodic magnetic field. Coaxially wound around the row is a first coil for inducing an alternating current perpendicular to the field and perpendicular to the periodic direction, while a second coil is wound around the coil orthogonal to the first coil to induce an alternating current perpendicular to the field and parallel to the periodic direction. An ultrasonic ellipsometer includes such a dual coil transmitting transducer for generating an elliptically polarized wave and a dual coil receiving transducer for detecting the wave after it has propagated through an electrically conductive medium. By using the ellipsometer to generate an elliptically polarized wave in a material and detect the change in polarization of the wave after propagating through the material, the apparatus can be employed to examine surface properties of the material.

Ultrasonic ellipsometer

A method and an apparatus are provided for ultrasonically inspecting a cylindrical object. The object is placed between the poles of a magnet to create a circumferential magnetic field in the object. A group of electromagnetic transducers (EMAT's) are placed adjacent the material so that the transducers scan the entire object when it is rotated. When an RF signal is applied to the transducers, elastic waves are generated in the material. These elastic waves reflect from defects in the material and these reflections are received by the transducers.

Ultrasonic inspection of a cylindrical object

The transducer is constructed from individual transducer elements arranged in an array and configured to exhibit a predominant, longitudinal mode transversely to the array. The elements are interconnected through thin flexible sheets. Each element is individually damped, and the transducer as a whole is electrically damped through resonance with the clamped capacitance and dissipation. Electrical control permits in-phase operation of all transducer elements or control with preselected phase differences.

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Thousand Oaks, CA, United States of America

Robert B Thompson