Patent Number: 053965337
Section: summary

BACKGROUND OF THE INVENTION The present invention is directed to a primary radiation diaphragm for a radiation apparatus. The diaphragm comprises at least one diaphragm plate adjustable in a plane perpendicular relative to the axis of the central ray of the radiation transmitter or emitter. U.S. Pat. No. 4,691,335, whose disclosure is incorporated herein by reference thereto and which claims priority from German Application 84 36 281(U), as well as German Published Application 14 41 312, disclose primary radiation diaphragms wherein two diaphragm plate pairs are respectively oppositely adjustable relative to one another in two parallel planes so that a rectangular gating of the x-ray beam is possible. The adjustment of the diaphragm plates lying above one another must, therefore, occur in such a way that only the opening that defines the radiation field is left free. The diaphragm plates are adjustably seated by, respectively, two mounts provided on sides lying opposite one another. SUMMARY OF THE INVENTION An object of the present invention is to provide a primary radiation diaphragm having adjustable diaphragm plates which is smaller, assembly-friendlier, more surveyable and has a less complicated structure. This object is inventively achieved in that a single mount is provided for the diaphragm plate and this mount engages the diaphragm plate and is adjustable along a guideway. An advantage of the invention is that the second mount of the diaphragm plate can, thus, be eliminated so that the requirements of the stated object are satisfied. When the ray beam of the radiation transmitter is to be gated slot-shaped, then it is advantageous when two diaphragm plates are arranged parallel to one another in the plane and are oppositely adjustable relative to one another. It is advantageous for precise guidance of the diaphragm plates when the guideway comprises two guide rails that are mounted on the same side of the housing of the primary radiation diaphragm and when the mount of each diaphragm plate respectively engages on the first and second guide rails via guide parts. When the radiation field is so gated quadratically or rectangularly, then it is advantageous when two additional diaphragm plates are provided in a plane parallel to the first diaphragm plates and offset by 90.degree. relative to the first diaphragm plates. These two additional diaphragm plates are also oppositely adjusted to one another. Other advantages and features of the invention will be readily apparent from the following description of the preferred embodiments, the drawings and claims.