Abstract: The ignition of spark gaps for the production of shockwaves in the contactless comminution of concrements, using a capacitor discharge is improved by providing at least for some time prior to the ignition proper a voltage much smaller than the breakthrough voltage for producing a small current between the electrodes that prepares a channel in the discharge gap.

Abstract: A lithotripter has a source for focussed shockwaves and an X-ray device which is mounted for relative displacement and positioning in relation to that source of shockwaves; an improvement includes a device for aiming and sighting in cooperation with the X-ray equipment that includes a carrier element defining a first pair of X-ray contrasting aligned reference points and two additional X-ray contrasting reference points, on a second line and intersecting the first line at a point of intersection at about 15 to 45 degrees; and that aiming and sighting device is mounted in relation to said source of focussed shockwaves such that the point of intersection coincide with a focal point of the shockwave source.

Abstract: A detachable connection between a light-guide fiber and a laser suited particularly for medical purposes comprises two coupling elements. In the light exit opening of the first coupling element an optical coupling system is arranged which is connected to the former and can be adjusted parallel and/or perpendicularly to the optical axis. The first coupling element comprises a device for generating an axial force on the second coupling element. Between the first and second coupling elements, contact surfaces with high thermal conductvity are provided, by means of which heat is transferred in the coupled condition from the second coupling element to the first coupling element.