| 摘要 |
<p>In an x-ray examination apparatus comprising a frame (2) to which are connected an x-ray source (3) for emission of an x-ray beam and an x-ray detector (5) that is placed opposite the x-ray source, and filter means (31) that are placed between the x-ray source (3) and the x-ray detector (5), the filter means (31) comprising an x-ray absorbing filter body (33) and drive means for positioning the filter body in the x-ray beam, the drive means comprise two disk-shaped holding members (37,37') between which the filter body is placed. The filter body is in a pivot-point (43) pivotably fixed to one holding member (37) and is provided with a pawl (45) that engages a curved radial groove (47) in the second holding member (37'). By joint rotation of the holding members the filter body is translated in the x-ray beam whereas by rotation of one of the holding members only, the curved radial groove causes the filter body to rotate in the x-ray beam. A filter means of the above-mentioned kind is of relatively simple mechanical construction and takes up little of the space available in the x-ray apparatus. <IMAGE> <IMAGE></p> |
