Abstract: Ultrasonic testing device with a test head which includes an electromechanical transducer, especially a piezoelectric oscillator, with an ultrasonic equipment and with a shielded cable which connects the test head to the ultrasonic equipment. The test head has two electrically conducting shields which surround the transducer in cup-fashion. The two shields are connected to the outer conductors of the triple coaxial cable. The outer conductor of the cable is connected to a metal housing of the ultrasonic equipment and is grounded.

Abstract: A method for the ultrasonic testing of bolts for incipient cracks emanating from a wall thickness discontinuity between thinner and thicker parts of the bolt, which includes placing an ultrasound transmitter and receiver in the form of a piezo-electric transducer on the periphery of the thicker part of the bolt with the discontinuity located in the near-field region, radiating longitudinal waves at an angle of 55.degree. to 70.degree. and transversal waves at an angle of 25.degree. to 35.degree. from the transducer in direction toward the discontinuity, and comparing the intensity of reflected transversal and longitudinal waves with an echo characteristic obtained from a test body corresponding to the bolt to be tested, having slots formed therein simulating incipient cracks of different depths, and an apparatus for carrying out the method.

Abstract: An electromechanical control device for displacing and positioning an object such as a marker on a cathode ray tube screen has at least one control column normally biased in a central rest position which is manually displaceable against the bias in directions corresponding to coordinate axes on the screen. Displacement of the column operates a slide potentiometer which supplies an input voltage to a voltage controlled oscillator which produces an output pulse train which controls movement of the object to be displaced. The object to be displaced moves to a final position with a velocity determined by the amount of displacement of the control column. The final position of the object is achieved by incremental step movements of the column, with column movement controlling velocity and direction of movement only, with magnitude being controlled by an operator.