DE562083C - Secondary radiation diaphragm for examination with X-rays - Google Patents

Description

Secondary radiation diaphragm for examination with X-rays The Grid of the secondary beam diaphragms used in X-ray exposures to achieve sharp images (Bucky screens) consist of lead lamellas that are sandwiched between narrow strips of wood (intermediate strips) are embedded.

The manufacture of this grid requires great care as there is this it depends on the utmost accuracy and uniformity. According to the known manufacturing process the lead strips are applied individually to the wooden strips using special devices glued and ironed. After the strips so processed have dried, they become smeared with glue again and glued together to form a grid with suitable auxiliary equipment. Although this known method is time-consuming and relatively labor-intensive requires a relatively large number of the grids produced in this way (due to unevenness in the version) cannot be used. This unevenness is especially created by shifting the cover strips when gluing onto the wooden strips and when gluing together the individual strips of wood covered with lead strips to form a grid. In the case of X-rays with a stationary bucky diaphragm, the uneven arrangement becomes apparent the lead strip in light strips of various widths. Sometimes it even happens before that a lead strip moved up close to the edge of the wooden strip and when peeling off the glue from the finished grids (with the scraper) pressed wide or dented. The strips of wood that are required because of the uniform X-ray permeability must not have a grain and therefore special are made of plywood. These plywood strips are not always completely plane-parallel, but sometimes have uneven spots. When a Strips of wood with an uneven point that is often barely noticeable during processing is, comes into the grid, the following strips are obtained when they are folded small bends, and this can also make the grids unusable. Because the lead strips, which are very thin, but a bit narrower than the wooden strips are placed on the middle of the wooden strips, are created when they are lined up of the individual lamellas covered with lead on both long sides with joints Fill with glue. The drying of this relatively thick layer of glue in the joints takes a long time; mechanical strength is also increased by such thick layers of glue. It is also used for the production of grids for Secondary radiation diaphragms use an adhesive that is disadvantageous for substances containing alcohol '(benzene containing alcohol, gasoline, alcohol, etc.) is dissolved, since when it is used such an adhesive spraying the grid with a spirit containing Varnish varnish (to achieve durability the grid in the tropical climate) is impossible, because in this case the glue spots would loosen again.

According to the invention, these disadvantages are avoided in that at least the strips (intermediate strips) of the lamellae that are transparent to X-rays Milled out on one side and in the milled grooves that are impermeable to X-rays (Lead) strips are inserted. The attachment of the lead strips in the intermediate strips can be done by glue.

The intermediate strips are obtained according to the invention on at least one Side and exactly coincident approximately in their middle millings (with a planing machine executed) on the width and depth of the lead strips. In this operation will be the surfaces of the wooden strips are planed plane-parallel and smooth at the same time. The lead strips are inserted into the grooves when gluing onto the wooden strips. A side Moving the lead strips when placing them on the wooden strips and when gluing them together of the individual lamellas to the grid cannot take place. Gluing the Wooden strips in which the lead strips are inserted goes relatively quickly in front of you, as there are no glue joints. The strength of the so produced The grid is increased because wood is glued to wood on the two long sides of the slats is. A glue is used as an adhesive in the new manufacturing process, which is not dissolved by substances containing alcohol, for example cellulose glue.

From Fig. Z it can be seen in which way the lead strip a is inserted into the milled recess b of the intermediate strip c. Fig. A shows a cross-section of a grid which is produced according to the known method and in which the lead strips a, when glued together, have slipped upwards or downwards from the central position in an irregular manner that is not useful for X-ray exposures. In Fig.3, a cross-section through a grid is shown, which is made according to the invention; the regular position of the lead strips a between the wooden strips c can be seen.

In the production of some, especially flat secondary beam diaphragms, in those as shown in fig. q. is shown schematically in section, the individual Lead strips must be strung together at different angles, according to the invention to compensate for the difference in inclination are proceeded in such a way that that the individual strips of wood except for the milling b (Fig. 5) on the one side also received a matching bevel d on the other side. Because the differences in the required bevel of adjacent slats are extreme are small, it can be dispensed with, each individual wooden strip with a to provide another bevel.

Claims (1)

PATENT CLAIMS: e.g. Secondary radiation diaphragm for the examination with X-rays, characterized in that they are transparent to X-rays Intermediate strips of the lamellas milled out on at least one side and into the milled openings the strips that are opaque to X-rays are inserted and, if necessary, through Glue, for example cellulose fibers or the like, are attached therein. z. Aperture after Claim r, characterized in that the millings in the middle of the intermediate strips are appropriate. 3. Aperture according to claim z or 2, characterized in that the Intermediate strips are beveled on at least one side. Supplementary sheet for Patent 562 083 Class 57a Group 7. From the patent seeker is considered the inventor given: Emil Kreul, Erlangen.