Abstract: A shockwave source of the type wherein a shockwave is generated by rapid electromagnetic repulsion of a membrane by a rapidly energized coil has a central opening extending through the membrane and the coil. An ultrasound head of an ultrasound transmission and reception system is received in the opening. The ultrasound head is disposed in a mount which is rotatable around its longitudinal axis by a rotary drive. In one embodiment of the shockwave source, the shockwave source also has a focusing device disposed in front of the membrane, and in this embodiment the focusing device also has a central opening in which the ultrasound head is received. The ultrasound head has a distal end in contact with a liquid coupling agent for promoting transmission to, and reception from, a patient to which the shockwave source is coupled. The shockwave source is particularly suited for lithotripsy treatment of gallstones.

Abstract: A lithotripter for disintegrating a calculus in the body of a patient has a shock wave source which generates shock wave pulses which are focussed into coincidence with the calculus by an acoustic lens. The lithotripter has an ultrasound locating system integrated therewith, the locating system having a mechanically pivotable element for undertaking a sector scan of a portion of the patient to identify the position of the calculus therein. The pivotable element may be an ultrasound transducer, or may be an acoustic mirror which reflects ultrasound signals from a transducer disposed laterally of the mirror, as well as reflecting echo signals from the calculus back to the transducer. The rotational axis of the pivotable element is disposed perpendicularly on the central axis of the acoustic lens.

Abstract: A lithotripter for disintegrating a calculus in the body of a patient has a shock wave source which emits shock wave pulses which are focussed to the calculus by an acoustic lens. As seen in the propagation direction of the shock wave pulses, a semi-transmissive acoustic mirror is disposed in front of the acoustic lens at a fixed angle. An ultrasound transducer, which is part of an ultrasound locating system, such as an ultrasound sector scanner, is disposed laterally with respect to the acoustic mirror, so that ultrasound waves are transmitted by the transducer to the calculus, and the reflected waves are transmitted from the calculus to the transducer, reflected by the acoustic mirror. Shock wave pulses from the shock wave source are only minimally impeded by the mirror, so that the therapy is substantially uninfluenced by the presence of the mirror.

Abstract: A measuring cassette for checking magnetic head insertion distance and tape guide height in a magnetic tape cassette machine. A spring tongue in the cassette has at least one strain gauge on its surface to measure tongue bending, and is arranged to be deflected by insertion of the head into the cassette so as to sense the head surface or tape guide alignment with respect to the cassette.

Abstract: A diesel internal combustion engine in which during the starting and partial load operation, a number of the cylinders are operated as compressor cylinders and a number as engine cylinders. The supplied charging air of one compressor cylinder (26) is used as actuating medium for the valves (35 to 42) which are to be controlled corresponding to the operating condition of the internal combustion engine, in the connecting lines (27 to 34) between the compressor cylinders (19 to 26) and the engine cylinders (11 to 18) in the absence of a compressed air network. As a result thereof, auxiliary energy of the internal combustion engine (10) is needed only for the initiating control and a rapid shifting of the operating conditions is attained with minimum expenditures.

Abstract: A torque-measuring test cassette having at least one annular member arranged to engage a winding mandrel of a tape cassette apparatus. A resilient metal strip extending radially from each annular member has a far end arranged to be guided in a slot in the test cassette housing, so that a strip can bend as a result of torque imparted to the annular member by a winding mandrel. Each strip has a strain gauge attached to at least one side to permit remote electrical measurement of bending of the strip and thus the torque exerted by the mandrel.

Abstract: A helical scan recording and playback apparatus wherein magnetic video tape forms a helix about the peripheral surfaces of two coaxial drums which define an annular gap for magnetic heads which orbit in a chamber between the drums and engage inclined tracks at the inner side of the helix. The heads are mounted on a disk which is rotatable on a sleeve surrounding with clearance a shaft for the drums and having an internal protuberance which is tiltable with respect to the periphery of the shaft by a rod extending through an opening in the flange of one of the drums. The inclination of the plane of orbital movement of the heads relative to the central symmetry plane of the gap is changed when the speed of lengthwise movement of tape during playback deviates from the speed of lengthwise movement of tape during recording.