Patent Number: 039768899
Section: description

DETAILED DESCRIPTION The X-ray diagnostic apparatus illustrated in the drawings comprises a single or unitary enclosure apparatus utilized for dental exposures. The apparatus according to FIG. 1 includes, in a known manner, a housing 1 filled with oil and which contains therein an X-ray tube, as well as an associated high-voltage generator. The housing 1 is adjustable into the exposure position by means of a suitable handgrip 2. The X-radiation exits through a tube 3 which focuses the X-rays. The X-ray diagnostic apparatus is connected, by means of a cable 20, with a timing switch 21, the latter of which possesses a push button 22. A cable 23 leads from the timing switch 21 to an electrical supply plug 24. From FIG. 2 it may be ascertained that the housing 1 includes an X-ray outlet aperture 4 for the X-radiation, and a filter arrangement 5 which is positioned intermediate the tube 3 and the X-radiation outlet aperture 4, the filter arrangement possessing a ray-impervious housing 6 within which there is supported a disc 7. The disc is rotatably supported proximate the X-ray outlet aperture 4 about an axis 8 which extends eccentrically to the main X-ray beam 16 (FIG. 3). The disc 7, in accordance with FIG. 3, includes three apertures, within which there are located three filters 9 through 11 for the X-radiation, and which have their center points located on a circle extending concentrically about axis 8. The radius of this circle is equal to the distance between the central or main X-ray beam 16 and the rotational axis 8. By effecting rotation of disc 7, which is serrated about its rim, one of the filters 9 through 11 may, respectively, be moved centrally below the X-ray outlet aperture 4. For this purpose, disc 3 includes three locking notches or recesses 12 through 17 spaced about its periphery into which a locking spring 15 is adapted to engagingly snap when respectively one of the filters 9 through 11 is centrally located below the X-ray outlet aperture 4. The filters 9 through 11 may, for example, consist of aluminum discs having varied thicknesses. The X-ray diagnostic apparatus possesses a fixedly set X-ray tube voltage and X-ray tube current of, for example, respectively, 60 kV and 7 mA, and a fixedly set exposure time of, for example, 1 second. The coordination with or matching to the particular exposure object, meaning, the particular tooth which is to be X-rayed, is carried out by positioning of the filter which is associated with that tooth below the X-ray outlet aperture 4. In practice, it is adequate to have coordination of the X-radiation to the types of teeth which are known as "molars, bicuspids and incisors". The upper surface of disc 7 has corresponding symbols designated thereon. Since the disc 7 has its rim project somewhat outwardly of housing 6 for enabling manual manipulation thereof, the particular tooth symbol on the projecting portion is visible, from above which is associated with the filter positioned below the X-ray outlet aperture 4. It has been indicated that two filters, which consist of aluminum discs having thicknesses of, respectively, 0.5 mm and 1 mm, as well as one aperture in the disc without a filter are suitable for coordinating with the particular exposure object in conformance with the three above-mentioned types of teeth. In the inventive X-ray diagnostic apparatus there is completely eliminated the need for a control panel for carrying out the setting of the exposure data. The coordination with the particular exposure object is effected by means of disc 7, which is directly located on the single-housing apparatus. The inventive object has, in comparision with the state of the technology, in addition to a simpler construction also the essential advantage that, notwithstanding a constant X-ray voltage, the X-ray penetration is changed by the filters in conformance with the exposure object, which meets the requirement of X-raying thin objects with a soft X-radiation in order to obtain a good contrast. In the inventive disclosure, a filter having a relatively strong absorption value for X-radiation must be employed for the X-raying of thin objects. Within the scope of the invention, the primary circuit which essentially incorporates the timing switch, may be constructed as a unitary entity with the single-housing generator, since no operative adjustments need be carried out in the primary circuit. From the circuit diagram illustrated in FIG. 4 it may be ascertained that the timing switch 21 includes a timer 25, the latter of which actuates contacts 26 connecting the power supply conduit 23 with the primary winding 27 of a high-voltage transformer 28. The timer 25 has a push button 22 associated therewith. The secondary winding of the high-voltage transformer 28 is divided into two portions. The winding portion 29 transmits the anode voltage for the X-ray tubes 30, and the winding portion 31 transmits the filament voltage. From FIG. 4 it may be ascertained that the anode voltage, as well as the filament voltage, and consequently the X-ray tube current, are each constant. A constant time is programmed into the timer 25. Upon depression of the push button 22 for commencing an X-ray exposure, the switches 26 are closed and the programmed time begins to run. After completion of this time, the timer 25 opens the switches 26 and terminates the exposure. From FIG. 4 it may thus be ascertained that the X-ray diagnostic apparatus is provided with only a single value for, respectively, the exposure time, high voltage for the X-ray tube, and X-ray tube current. While there has been shown what is considred to be the preferred embodiment of the invention, it will be obvious that modificaions may be made which come within the scope of the disclosure of the specification.